This is funny. But also true. And it is actually true for a lot of engineering. At least it is my experience. I think it is a sign of a complex system.
That is so accurate and I am 100% guilty of it. 3D musketeers refers to it as chasing zeros. And I forget I think it was teaching tech. That said, when things get bad just start back over with a generic default profile
I love how you captured one of the most amusing things in 3d printing... how a print can fail, and then.... half recover and start making good layers again on top of the junk is spewed.
I run a small print farm and from my experience Zhop is a great peice in my reliability toolbox. Zhop, retraction, avoid printed pieces, mesh bed leveling and temperature all play a needed part in making sure that I have as few failed parts as possible while printing at 100+mm/s
@@GiovanniGiorgo I sell prints and run at 500 on my x1c. They aren't crazy detailed small models ofc but it's at 500-600mms in abs and is way better quality than my old printers
@@liam4686 sure if you've got an x1c or a highly tuned voron v2 but that's not reasonable for a print farm, I don't have $15k to drop on a new bank of gucci printers with untested reliability. I use ender 5+ base printers with btt mobo, bgm extruder and V6 volcano hotends and they are happyest around 150mm/s with 10k acc. I'm currently looking into upgrading to orbiter v2 with V6 heatsinks and sprite heatblocks with CHT nozzle which I hope will let me go to 200-300mm/s while still maintaining the quality I need. Which when you factor over 12 printers running near 24/7 is a massive throughput.
for me printing in ABS i've found that Z hop saves the print from being whacked over from the inevitable curling that happens on overhangs an arches but thats in air or in a enclosure
Interesting thoughts about Z hopping. Just to satisfy my own curiosity, I decided to try printing the circular Z hop test .STL, with and without Z hop turned on. The printer I used is one of the most underrated printers on the market and is my second cheapest printer, a Kingroon KP3S (US$150) that is totally stock except for the addition of a BL Touch sensor and a PEI flexible bed (smooth surface). The filament I used was a silk PLA made by Tttyt3D (I know, screwy name, but it prints really well). The slicer is Cura 5.4. The Z hopped model was done with 0.4 hop distance, 220C hot end, 60C bed, no supports, and no brim. Printed without problems in about 34 minutes with just a few very, very fine hairs of stringing, mostly on the first 10mm of the model. For the second print I turned off the Z hop and everything else remained the same. Again, the part printed with no issues in about 32 minutes, a two minute savings over having Z hop turned on. The major difference was a perfectly clean print, no stringing at all. Both prints came out flawless as far as surface finish. Another thing to note, the spool of PLA has been sitting on my printer for several months and shows no issues with moisture contamination. So the bottom line is printing WITHOUT Z hop turned on results in shorter print times and greatly reduced stringing. Lastly, it just goes to show that an expensive printer doesn't always guarantee quality prints. I've been using this printer for almost two years and the only thing it has needed was a new nozzle.
i use z-hop all the time, and it's quite useful.. from what you've shown so far (TS 00:02:48) Most of your z-hop woes are caused by improper use. you should always "wipe" before doing a z-hop, this lets the built up pressure in the nozzle to be aleviated BEFORE the z-hop, which greatly reduces the blobs and boogers. the scarring you're seeing on your ironing, probably has more to do with your ironing height &speed, than it does with z-hop. Also, you keep blaming z-hop for the stringing, when in fact, most of the stringing issues you're having are due to incorrect retraction settings. the whole point, is to reduce, or eliminate the "oozing" of filament due to back-pressure when you're traveling
Ozzing is made worse by z-hop. Once you retract and pressure decreases material will still flow out of the nozzle, especially if the nozzle instead of moving quickly to the next colum has to move up then over and then down it takes a longer time where the material can and will ooze out.
@@Penofhell It does because pressure can only be relieved but it does not disappear. Pressure advance tells you what kind of pressure there will be at that curve in advance but pressure will be there no matter what you do it is inherit in the FDM print process. You can decrease the pressure but you can not suck the material back into the nozzle. It will ooze the question is how much. That´s why fast movements are important.
thank you , wipe is the most useful tool in prusha slicer , it completely eliminate blobs and in combination with retraction can completely remove stringing , at that point Z hop is redundant, also wipe can forgive and actually prefers over-retraction
I have actually successfully printed a very similar part. It was a print in place roller bearing for filament spools. It worked actually pretty well, but i usually use PETG and an adhesive for the bed (and my parts usually stick really, really well). Since I use PETG, the viscosity is not the issue when knocking over parts. Molten PETG is more like thin honey consistency wise compared to the toothpaste like PLA. The issues were more with the outermost perimeter being pulled up by surface tension, making these areas higher than the innermost parts. This accumulates until the nozzle touches, then pushes down these areas. This leads to the nozzle slightly wiggling the part until it is ripped from the bed. There is a combination of ways to mitigate this, from extrusion multiplier to finding the optimal layer height - though this will highly depend on printer, filament and the model you want to print. As said, this seems to depend on printer too. My delta will tends to have issues like this, even with z-hop, while my i3 clone works with just the teeeeniest bit of z-hop and almost never knocks anything over. Levelling and bed flatness might also be a factor to consider. Advice though: Don't design parts like this, thin pillars just don't print well. If you absolutely need to then use adhesive, slightly under-extrude and use a raft.
This explanation deserves being included in the Bible of 3D Printing by however is to write it. I've been banging my head to understand this phenomenon that happens with certain filaments. Now I need to understand how to overcome it.
@@DeagleBingo yep. Tinkering fits certain personality types. RC planes, drones, reloading, 3D printers, woodworking, etc. There's a lot of overlap between these.
I've been using Z-Hop religously ever since my early printing days when I would hear the "grinding" my nozzle made scraping across my print due to over-extrusion. I hadn't thought about the time retraction takes. Thanks!
I agree with your points if you are printing slow. Once I started printing at 300+ mm/s, i needed it on with more complex prints otherwise it was knocking my tree supports off. I will continue to dial in the trees to help see if I can make them better, but for now this setting seems to correct that.
yeah my p1p thinks it's a lumberjack too the way it mows over trees. I ended up going back to regular supports, could never get it to stop mowing over trees and got tired of wasting so much time and filaments. While watching it, I noticed it seems like the slicer don't remember where trees are and avoid them while traveling. At high speeds, trees knock over so easily, even with giant brims. I seen a bunch of times it rips the tree right off the brim.
I went through the rabbit hole of this too and went back and forth between z-hop enabled and disabled for about 6 months now - and since I've got all my other setting dialed in, I ended up with leaving Z-Hop on. Z-Hop *can* harm your prints' quality, but from my experience *only if improperly used* - while it provides quite a few advantages. If used correctly however - particularly paired with fitting retraction and a well configured wipe move - I end up with much less problems and higher print quality overall. I tend to argue that it depends a lot on your particular printer model, and of course all the other variables like particularly the type of filament do play a role as well. As stated, with my Ender3 S1, after very long testing I found that it not only improves my print quality, but also avoids lots of issues some prints may cause. Particularly it avoids catastrophic print failures when having to deal with warpy filaments.
When I add z-hop when retracted on my ender 3 s1, stringing is absolutely terrible. I can't figure out how to get rid of the stringing when z-hop is on. Do you have any tips? Thanks.
Given the demonstration on when the print fails, I think a follow up video on techniques like linear (or pressure) advance might be interesting to see if that has anything to do with the failed prints. It probably doesn't have to be z-hop focused, since both settings failed in the same way. Also, even though I like video, it is not fair to say from this video that z-hop is ruining these prints. This printer/slicer setup is clearly not tuned for z-hop. I and many others get high quality prints and low failure rates with z-hop.
I probably should have been more clear on the process behind the video, which seems to be what's annoying people. I spend typically many days investigating a subject without filming. What makes the video is usually not nearly the amount of work done behind the scenes, it's actually mostly filmed afterwards. I have tried to work in other ways but it results in too much footage and a poor narrative. I think around three weeks of experimentation went into the findings here, overall.
@@LostInTech3D regardless i think its important to define the problem properly or at least try. in as much as that is what you are doing... that is why i watch. can't figure out a solution if we can't even describe whats happening right?
Actually in my opinion z-hop is a must to have on multi material prints. I often do manual filament changes at the 3 bottom layers to embed coloured text or graphics. As each colour is printed after each other, on small areas the nozzle can kick of already printed layers of the bed. For example if you print an "O" (like on the display case of an "Original Prusa") and print the text colour first, pinting the inside of the O with case colour the line of the O is very easaly touched and caried away. In oposite order (case colour first) the inside of the "o" can easaly be catched away. So here z-hop (and printing very slow) seems mandatory. But many thanks, I have not thought about turning z-hop on only for the layers I use colourchange before. I might try it on one of my next prints.
This is what I only use Z Hop for as well. When I do these type of multi-color prints I only enable the Z-Hop for the first three layers and then anything printed above those three layers Z-Hop gets disabled again.
Not sure if this video will stop me from using Z hop, but the info here is really useful and interesting. It could be filament, tuning and such, but I don't see any of the stringing that appears in the video. I'll definitely be looking for some of these situations, especially with smaller parts. One of the reasons I like z hop is when printing complex parts since it does eliminate the nozzle scraping over the part. Moves within complex parts are a different thing than traveling in the spaces between multiple parts. With complex sides, multiple holes, etc. it's not always possible to avoid moves over areas that have already been printed for that layer.
I enabled Z-hop in Cura a while ago because I found the nozzle scraping when moving over infill or solid layers, haven't noticed a decrease in quality but then again my Ender 3 is far from stock anymore. I do notice the Z stepper gets pretty toasty... For mods I have the dual lead screw belted together with a single Z stepper. I also added thrust bearings at the top of the leadscrew so they turn smoothly even when pulled down. Edit: I did notice the fluff too, the very light stuff is easy to clear with a lighter thankfully. I might try it without for some prints to see if it makes a difference.
Add some cooling to your steppers. Some people here on RUclips have had success using even PLA to print stepper heatsinks if you don't want to buy one, or you can bend some tubing around them for liquid or compressed air cooling. (Not strippers, DYAC! There's no paint or poles here!)
when my print slightly cools it expands a little causing the scrapes. it gets worst when the surface is a large surface area causing excessive drag on the head resulting in layer shifting.
@@Shinobubu i don't know the real solution but you're hitting on the thing thats become the obvious elephant in the room to me. its plastic. literally in the definition of the word. no matter what kind... its still changing shape slightly even after its been printed. and no matter what we have to acknowledge that we are asking this plastic to do two things at once and it can only do one thing at once. heat up and stick to yourself... no wait cool down immediately and don't move! nope. theres a balance there somewhere. only thing i've been able to do to get around this kind of thing is watch closely for when what you are describing is happening and baby step ? is that what its called... the z up a couple thousandths. maybe thats already something that is in a setting somewhere. i don't think its the same as z fade at all. and now that ive said this i'm considering simply adding something into the g code every 5 layers or something that moves the z up just a tiny bit more than what it would normally. if i'm dumb and this is already something i can enable please tell me and i will.
I once had a use case where I had to turn on Z-hop: I was printing TPU patterns onto some fabric on my V-Core 3 500 and the only way to avoid the hot TPU staining the fabric where I did not want it to was 2mm high Z-hop. With the large heavy bed this made for very impressive sounds and visuals 🙂.
Thank you! Thank you! I have wasted so much time and plastic trying to get a model to print without ripping parts loose. After turning off Z hop, prints are successful, not on the ones that worked part of the time, but even the one that never worked no matter what settings I changed.
When printing BIG parts with 1mm layer height, no perimiters and top layers, the Z-hop come very much in handy. As there are hundreds of places with no or very little bond to the previous layer, the filament curls up and make the steppers skip
I always use z-hop, and I rarely have ANY stringing. Any stringing issue can generally be dealt with through adjustment in print temp, retraction distance, retraction speed, wipe distance, and combing.
Isn't your model a great use case for a raft? The small base area of each pin doesn't give a lot of adhesion with the bed, and as the model gets wider as you travel up the Z axis, it becomes unable to stay stuck. Certainly I'd be looking at using a raft if I didn't have much surface area on my model in direct contact with the build plate and had a comparatively large height to print
Actually it would be only if it were not a test print. The whole reason for such a test is to find out if you actually can avoid the towers been kicked by using z-hop. If you use a raft, it wouldnt be kicked in both szenarios, so no use in the test. But of course, being kicked in both szenarios also proves nothing. In my opinion the test simply has to be scaled down in z. If there is a hight there with z-hop the towers do not fall but without they do, than you prove an advantage of z-hop for this case. If not, this proves z-hop being useless here too.
Thanks for the video. Newer to 3D printing, and went down the path of using Z Hop. It didn't help so much and added stringing every time. The best solution I found was to turn up bed temps during initial layer. For me, this seems to work, and I have fewer failures overall.
Good job finding the cause. Ways to cut viscous drag (shear force) in half: 1) Raise nozzle temperature by some amount, which you already tried. 2) Double height of Z-hop. 3) Half the travel speed. 4) Double the layer height. 5) Without reducing layer height, select a 0.3mm nozzle instead of a 0.4mm nozzle. Also, the tip should be narrow and pointy, without a large flat surface for ironing. Of course, the problem with most of these solutions is that they increase the time and/or tendency for filament to ooze from the nozzle during the travel move.
I was very surprised to successfully print this on the first go with no issues... Ender 5-S1, out of the box... No z-hop, 0.4 nozzle, 0.2 layer height, 120mmps, no raft or brim, single skirt, 3D-LAC spray on the bed (as always). 35min print time. Minor wispy stringing was the only issue... I posted my make on your printables... Cool video and certainly got me thinking about my printer's capabilities. I also printed Angus's @MakersMuse Clearance Castle and the torture toaster with perfect results and all clearances are free moving. I feel like the 5-S1 has taken the skill out of 3D Printing as this was surprisingly straight forward.
I discovered such stringing myself with z hop as well. And took me days to figure it out, by literally staring at the print as it was being done to see that that little hop carries the smallest amount of already laid down plastic with it. Luckily, in the end it got me to realize my belts were too loose anyway.
This is a brilliant video! I think the kind of " sticky " nature of molten plastic is like really overlooked and is such an important concept that in some cases it even prevents some prints to finish!
i feel like he's found why this happens for this model. at these settings... at this nozzle size... and with this filament. and imho this naturally should lead us to consider the physics of the plastic itself as it cools (which i am NOT saying i understand at all btw). which i think is what pro level 3d printer mfrs sellling 10k+ units to engineers have done more of. the fact that as the print cools down or does whatever it does in whatever specific circumstances... changes the way it reacts to the "drag" of the viscous molten material pulling as the nozzle moves... imo there's no getting around the fact that no matter the glue or bed surface that the bed adhesion itself changes over the course of the print time. its something i keep noticing no matter what i do. none of the printers we use as consumers ... and maybe none of them in existence even... can completely control all the variables. and a different astute commenter made the great point that these variables we try to alter all seem to overlap each other to a certain extent too... obviously enclosing the area is better, having it stick down harder to start with helps... etc etc etc.. even then my understanding is that all plastic still warps or contracts/changes shape as it changes temperature. so until we can have some way of like... i dunno.. printing a ledge that then gets clamped down to the bed, or theoretically screwing the print down to the bed from the underside or having some ideal situation where the stuff is a heated liquid only when it needs to be but then is immediately cooled to room temp solid once its put where it needs to be that we're always going to be fighting adhesion or subtle changes in the shape or size especially with any models that have small contact patches like this one that he made.
Most of my prints are small parts, 6mm diameter cylinders and up, and others of various sizes. The filament varies depending on the end use. The range of plastics is Nylon (Taulman 910), CF-Nylon(Different manufacturers depending on what nylon content.), PCTPE (Taulman), 75D TPU (NinjaTek), 95A ( NinjaTek, Sainsmart), 95A (Overture - a little softer than the other 95As), PETG (Oveture - over 200k used), PLA (Rarely used). The key element to successfully printing small parts like you were testing is to print them sequentially. I have been using this strategy for close to five years with a very high success rate, close to 100%. Granted, you don't get as many parts per build but the fit and finish, and the strength are near perfect. Oh, and your stringing between parts is close to zero. I also keep my prints under 3 hours. Prusa Slicer 2.6.1. No Z hop and very low retraction. Avoid crossing perimeters: setting. I also use Garolite to print almost all of these filaments. I use gluestick for the nylons and Aquanet hairspray for the TPUs and PETG, More as a release agent than for bed adhesion. I hardly ever need a bring on the smallest of parts. I'm using Prusa MK3S and Prusa MK2s.
I use Z-Hop when printing thin multi colour parts, such as earrings. Enables me to leave each part on the plate and fill in the gaps. Z-Hop at about 1mm for 0.5 - 0.9mm parts.
I had a print that was consistently giving me severe layer shifts at one point in the print. This was after switching to flashprint from flashcloud for slicing. This piece had an overhang edge the slicer was moving past and hitting with the head. I have a textured build plate with truely awesome adhesion. Rather than dislodge the part it was shifting the build plate a bit and/or making the stepper motor skip steps. This was fixed by turning on z-hop "when crossing part edges". In retrospect perhaps the default 109% extrusion rate was also contributing. Calibration tests since then suggest this is excessive for part dimensioning, but definitely helps with layer adhesion.
I was doing a print that had a fair amount of tower supports. Afraid the print head would knock over a support, I turned Z-Hop. Every time, the print failed. When I was re-slicing, I accidentally turned Z-hop off and that print was successful. Two other settings I found useful for the quality of the print is Z-Seam Alignment and Infill Start Point both set to Random. This prevents a single seam line to be visible on the piece because of the print layer starting in the same place every layer. Same goes for the infill start point. "Random" is your friend!
In my experience, my parts were failing. When I was new to printing, I switched from Z hop OFF to Z hop ON. I never had a problem since, nor have I changed the setting. Good results, clean ironing. I set my printer to print at 60mm/s. Biqu B1, stock. No catastrophic failures. I'll experiment. But as for those pins not sticking, I'd use a raft. If nozzle hits, have to reassess. I need functional parts.
I usually print initially without it, and if there are problems I give it a try and use the version that works better. There were maker videos here about 2 years ago that were fairly thorough as well showing specific cases and printers that Z-hop fixed the problems they were having, particularly with stringing iirc and ironically enough. Combining the 2 thoughts together I would imagine that improvements in slicers and printers and print surfaces have changed the playing field. Ive learned over time that when changing some variable of printing there are almost always at least 2 other variables that need to be considered, its almost always a 3 way problem or more. So with each modernization we'll have different settings that need to be adjusted.
In my experience, filament is not viscose enough to overcome bed or layer adhesion. When filament viscosity causes a part to fail, that is usually because the part has already partially failed earlier, e.g. the printhead already bumped into the part in an earlier layer causing the part to break, it just didn't fall over yet.
Most of the time Z-hop isn't necessary. I think the time I've needed it most is when I don't have adequate cooling in combination with thin, steep overhangs; that's when the most extreme curling will occur. (You should have seen the prints on my first kit printer that had NO cooling. Curling was a huge struggle, as was warping on long parts on the non-heated bed. I'm having PTSD thinking about that.) Generally, speaking, however, you are right about it just causing unnecessary stringing. Being that I forget to turn it off, it's probably why some of my modified PLA (so-called PLA+) filaments will string like heck.
I agree on this. Z-hop seemed fine, but in all my prints I had issues with it - and it does add a bit of time to each print, every up/down time adds up over the hours of printing after all. there were some attempts to turn Z-hop into a V shape, so it retracts, moves both over and up at the same time, then back down while still moving over, and then begins to print again as well - which seems better for the time loss, but still can leave unwanted melted spots, and the issue of vicious melted filament sticking and instantly connecting and being cooled to harden - then causes 'grabbing' and can move/destroy parts. better part cooling exists now too - which helps that curling effect go away.
Hello, I've been using Z-hop since I started with the Sidewinder X1 and it has definitely solved the problem you mentioned. I've never removed this setting again because, after checking, it doesn't save me any printing time or very little, which, compared to having to start a print again, isn't worth the risk. On the other hand, I don't notice any deterioration in my prints, they come out clean and without the stringing you have on the prints you show us, perhaps a setting on your own printer is to blame for these filaments because on the X1 I don't have this phenomenon. I've downloaded your model, and I'll be testing it soon (if I don't forget) with and without the Z-hop, whose height I've set at 0.125mm so that the nozzle no longer touches other parts of the part being printed. So if I don't forget to do the test, I'll come back and report what I find with and without the Z-hop in your file.
Seriously man you're over thinking this way too much. Z hop is not the issue here, barely sufficient bed adhesion is. If you have no oozing, good pressure advance and a very fast printer (including Z), z hop basically has no disadvantages and it solves a few unlikely failure modes, namely hitting a small corner area that curled up and is thus sticking out.
I was just going to say the same thing. The test is flawed. ZHop is not the issue, the bed adhesion is the bigger issue with the pin ZHop torture test. Also the claim that ZHop doesn't prevent scarring is not true either. With it turned on and also combing for me in Cura set to off I don't get scaring of the top layer anymore. And the fine whisps of stringing, that could honestly be retraction settings or depending on the material being used may need to be put in a filament dryer box. Point being, putting all blame on one thing is wrong. It's more likely several other things could lead someone to believe it's only one issue when they're not looking at the entire scope.
So I simply _had_ to turn on z-hop while using prusaslicer because every time it would move over the tree supports (i haven’t had a single print get knocked over due to nozzle travel since, though I have run into that viscosity issue you mentioned), it would knock them over and fail the print. I honestly don’t care about the stringing because a heat gun easily takes care of anything like that and produces a perfect print.
Great video! Personally i will be leaving Z hop ON when printing multiple parts(with collision avoidance aswell jic). In Cura, using it with COMBING MODE "not on outer surface" gives me amazing results with good top surface finishes. Zhop has to be configured correctly to get nice results, i have it raise 0.7mm and 40mm/s - faster means minimal stringing and it never hits printed parts off the bed or misses steps because of a collision... Finally one more thing to concider is filament ooze - could it create high spots while moving over parts (with z hop)? Most likely yes - in my case tuning in Linear Advance to eliminate ooze helped A LOT with parts getting knocked off.
My biggest issue in Prusaslicer was that the 'equivalent' settings, 'avoid crossing perimeters' and 'avoid curled overhangs', decidedly did NOT avoid crossing supports. This cause me big issues during the 2.6 alpha, because all those shiny new organic supports had a tendency to get sideslammed and that amount of torque on either very tall or very thin branches would very quickly cause them to fail, and I'd be lucky if the failed support didn't take the rest of the print with it. I'd be curious if the higher temperature idea would work in my case, but zhop was a simple fix to the problem at the time. Honestly, I wish there was a was to identify a surface or object (like supports), and specifically enable zhop when entering that specific area.
V400 here...bed adhesion is essential when printing high at high speed. Make sure your print can't get knocked over. Hotter extrusion, better cooling all helps. A hotter nozzle will also just go through the old layer instead of hitting it.
z hop helps mitigate the nozzle dragging across infill, since cura overlaps infill lines at crossing points giving them virtually 200-300% extrusion right at the crossing, which causes it to get raised a bit and without 1 layer of lift it usually drags. the fix would actually be to not overlap those infills but ultimaker couldn't care less (it's the only reason ive gone from cubic subdivided to gyroid, its worse but when going at 250mm/s cubic tends to grab the nozzle so hard it skips steps and ruins your print)
I remember the community post with the question! Thanks for the great research, it's much needed. It's really hard to convince people that what they're observing might be affected by concurrent causes when discussing any parameter.
I never use Z hop. I use thick layers of purple glue for adhesion, then remove with ultra thin artist pallette knife if it sticks too well. They pop off effortlessly with those. I think those are essentials for any printing enthusiast!!
Tried to make that model of yours. Printed fine with or without the Z-hot. Though of course, Z-hop had a lot more stringing. For reference: Creality Ender 3 V2 Neo Modified with hardened glass bed and direct drive for Ender 3 Steel grey PETG from C-tech 0.12 mm layer height standard 0.4 mm nozzle 50mm/s printing speed Full infill no supports 230 C nozzle temp 80 C bed temp
I've never used z hop ever. I print articulated figures that requires printing multiple small parts. I've dealt with issues mentioned above and for me the biggest game changer is part cooling. It'll help with dialing in your retraction, tempreture, and help prevent stringing and curling of overhangs. Some useful slicer features to further help with these problems is the per model settings in cura. I could set a slower printing speed independently for some tall, norrow parts that are prone to failure. Stay away from z hop specially if you have an old ender 3 style printer with a single lead screw.
ABS is shrinking more than PLA or PETG and it will curl up. Z-hop of 0.4 mm definitely helps printing ABS, when your toolhead whizzes at 160 mm/s speed and 300 mm/s travel moves. You have v0, you can easily tune it to those speeds, load up ABS and try yourself 🙂 If you think Z hops are slowing you down, you can do Z on belts - CoreXZ, flying gantry, belted Z mods.
printed the pins in circle n ABS no brim without any problems, took about 24 minutes. printed with 0.1 mm z-hop. came out fine. Machine: Voron V2.4 R2 stealthburner with LGX-lite extruder, klipper
Yup, Z-hop was a massive issue for me. I turned it on in the beginning when I had some other issues, causing filament to curl up, which the nozzle then ran into, ripping the print off. Z-hop fixed that issue, but caused SO many other issues. With more experience, the other issues I experienced were fixed with better designs, better bed adhesion, better leveling, etc., so Z-hop did nothing but hurt my prints. It also massively increased stringing in my case.
Tried the "unprintable" on my ender 3 pro, the surface was a bit rough but it printed succesfully the first time, ASA filament, no Z hop, sliced with CURA with skirt, no brim, printer is a bit modified, V6 all metal hotend, print bed is coropad on a spring steel plate, SKR board running marlin, linear advance, ABL, and a closed enclosure (heats up to about 35-40C from the 90C bed temp)
Also, you're using silk filament for those pins, which is WAY more viscous than regular non-silk PLA. I'd be curious to see a comparison video about THAT
yeah I was hitting it hard with my worst filaments, to try to cause extreme issues. It definitely would be a good video, but if this one is anything to go by, it will be....uncooperative
I use Z hop for tall, narrow pieces where any nozzle bump may cause a failed print. Strangely, and seemingly counter intuitively, when printing with materials that have poor bed adhesion, the "pulling" effect causes it to unstick from the bed and makes it more likely to fail. When I /do/ use Z hop, I tend to use a pretty high hop, enough to make sure to break any ooze, usually 2mm.
Man, Z hop was disabled by default on my printer. After one particularly difficult print kept failing I found that and enabled it, and solved a TON of other issues as well! SO MANY problems are caused by the nozzle just barely grazing the edge of a print as it moves around and throwing off the alignment and Z hop completely removes that issue. (With Cura and a Ender 3 Max Neo) But all of these settings interact...and unless you're spending half your time on just calibration prints you're not going to get everything perfect. Maybe Z-hop is easier for you; maybe you'd rather spend a couple hours dialing everything in to hundredths of millimeters of precision...all depends on what you're printing and why. For my own use case, z hop is excellent.
Setting up z-hop correctly with the right height and retract values has done nothing but improve the success and quality of my prints. I highly recommend giving it a shot!
Interesting. You could see thru the brims on some of your prints, like gaps between the layer lines. Maybe more squish would help. Otherwise you should have used a RAFT.
On certain printers like Voron 2.4 that have belt driven Z for the exact reason of having extremely fast z-hops I think it does not apply as much. I may need to do some testing but from the printing done so far it looks like with a very fast Z move it actually helps break the plastic string and works reasonably.
Interesting video, but completely opposite to my experience. On my Biqu B1, Z-Hop eliminated the nozzle knocking over curled up PLA overhangs. On my Bambu Lab X1 Carbon, Z-Hop is on by default and has never been an issue (temperatures are set a bit higher than normal though). I also never saw any additional stringing in PLA with Z-Hop enabled (to me, stringing is more indicative of wrong temperature or retraction settings).
Thanks for your info. I wasnt sure z hop really helped any way. but with printers going faster the knocking over is going to be alot more common. i think a reall indepth analysis on thhis is sorely needed, to find whats going on. very informative video, great job.
Like others in the comments have said, poor retraction is the cause of the stringing. I had Z-hop woes when I started 3D printing where having it enabled would cause missing outer walls and other weird problems. It can also exacerbate stringing and branching if retraction isn't tuned right. Turns out, Z-hop causes that if it lifts up too fast, too far. Generally it should be equal to or less than your layer height. I find Z-hop very useful when printing delicate bridges and overhangs, like on E3D's Spider's Web stress test. The print almost always fails without Z-hop.
I have Z hop on almost all the time if the print needs supports, because no mater what i did i would hear scraping on the infill and i would often come back to a printer 10 or more hours later to find that one or more of the supports had been pushed over and the print failed, however if all you are printing is a flat object or something that does not need supports then it is not needed. There is no real disadvantage yo having Z hop on as it completely removes the possibility of the nozzle striking the print or support material, people often say it considerably increases print time which is false because if you like my set up have it set to twice the layer height so 0.4 but then dial up the speed of the Z hop it actually adds a very small amount of time ( about 22min on my last 12 hour print ) as for the stringing you experienced looks like a profile issue ether you are running to hot or your retraction is not set correctly or a common error people make is not turning on retraction during zhop
If hop is off, the nozzle may wipe itself on the print as it moves. When hop is on, you should wipe before the lift to eliminate the stringing. I have wipe+hop in the profile I use.
Z-hop is exactly a safety feature that's turn on by default as it slightly increases the chance of success of prints. It may result in worse quality, but it eliminates the knock-over concern. If you have a fine tuned file and printer it's not necessary to have Z-hop, but manufacturers keep it on as it lowers frustration in general for most people.
No matter what I did I couldn't stop the nozzle from catching on the infill and making that noise so I opted out to use z-hop. That 'grinding' isn't really problematic most the time but sometimes it can move a part slightly or knock it off. I really did try so many things to change that and I mitigated that grinding but I couldn't get rid of it. Maybe it's related to the manufacturing of my printer, who knows. My Ender 3 V2 came with a faulty board as well, so that was fun... I thought changing it would fix everything but that particular thing wasn't fixed. I guess this is mostly per-printer or per-user preference since z-hop has its upsides and downsides. If you can't help it you use it, if nothing works use it.
I have not found any reason to use it as long as my machine profiles are dialed in properly. I will occasionally run z-hop on tricky TPU prints... But, I pretty much agree with everything said. Lost In Tech, thanks for another great video.
I just sliced and printed your impossible file and it printed fine. Bambu lab x1carbon, bambu studio slicer, default pla settings and there is a z-hop. 1 wisp of stringing and some minor droop of filament on the 90 degree top/curve.
I won't use Z-hop very soon, for the parts I print (rotors, bigger pieces) it's useless. I was also wondering and blaming filament for the "cotton fluff" stringing. Useful video! Thanks! Later edit: I just did disabled z-hop and it was the missing piece that caused imperfect prints. The differences in my tests were more obvious than shown in this video.
Materials that collect on the nozzle when travelling, like PETG, will accumulate, cause blobs to forum, and fail the print when crashing into the blobs. "wiping" the nozzle (with out Zhop) increases this issue. if any portion of the print has over extruded( like sections of solid infill), this will be even more important to avoid. In a perfect print, where you never over extrude even a tiny bit, then you don't need Zhop. The more solid the print, the more needed zhop is.
oh boy glad yt algorythm showed me your video. I was struggling with printing things and now I changed the slicer but maybe its zhop. I will test it with what I was printing and your torture test.
IF using Z hop to prevent gouging, I've found it a good idea to engage 'wipe' function in Simplify3D. This combines with the retraction to clean the nozzle and prevents stringing.
I never use zhop, mostly because I believe that the issues that cause prints being knocked over are indicators that there is a problem with the machines tuning, and I can usually fix the issue and have good prints again with a little troubleshooting. Any setting that doesn't make the fact that there are issues with the print obvious is a complete no-go in my book. Not everybody wants to deal with every problem if they don't absolutely have to, but I would suggest eventually dealing with all printer problems if you want a better long term prints.
disabling Z hop except for first and last layer in Orca Slicer completely fixed my horrible stringing issue. It went from a string connecting every layer on a tower test to absolutely zero strings.
I agree Z hop is not always a good thing. but I can say that if you have a model / structure that has a 45° or lower angle (from the print bed) the last layer will have a small amout of it with no support and this will curl up and when the nozzle comes back from and other area if it aporaches direcly twoards the little curling up lip from the edge you will get a collision and this may knock the part off or cause some astifacts in the layers.
I just printed the test on an FLsun QQS Pro, using cheap PLA and default settings in Cura 5.3.0, without any problems, just a tiny bit of stringing between the pins.
Bedslingers: On Corexy: Off (since bed does not move back and forth) Your print might have failed on z-hop since the base had little support. The nozzle basically picked it up on the way.
I don’t understand why people struggle with build adhesion. 1. Make sure your nozzle is set to a height that the first layer is correct, it should be smooth, not spider web looking. 2. Glue stick every time, period. 3. Keep the bed at 60 degrees (or whatever your filament recommends). Use a skirt to prime the nozzle. 1.5 years of printing and I’ve had exactly one print fail build adhesion and it’s because I forgot glue and it was a 15mm scale apartment building so eventually it got in the mood to dance on the build plate.
I bet the hot end shifting on the roller bearings is what actually happens. When the filament sticks, it's enough to shift the hot end to the extent of it's backlash. Then the nozzle collides with the part. It would be interesting to see this in super slow motion and macro.
I see in your example of the Zhop stl that you are using Cura Try these 2 changes Uncheck avoid printed parts while traveling Cut your travel avoid distance in half (0.312) It's not always about more clearance when traveling I've found regardless of which slicer I'm using (Cura, Prusa slicer, Bambu Slicer, Orca slicer) that sometimes slowing things down and adding more travel clearance to avoid things like stringing, blobs, lines on outer walls, and general adhesion issues causes the Slicer engine to add extra or certain unnecessary moves which makes things worse and can be very frustrating Not to mention, there is no single group of settings that will give the best consistent results for every model Z hop and retractions are excellent tools but must be kept at a minimum rather than a maximum For 99% of my prints infill combination is selected and my line width for the infill is the exact value of the nozzle size I'm using where as my walls and top surface on say a 0.4mm nozzle are 0.42mm to 0.45mm depending on the size of the model with a layer hight between 0.12mm to 0.25mm That's only one example using Orca which I'm now using on my 3 clapped out bed slingers and my X1C I'm still on Orca 1.6.2 but will update once the latest version comes out of Beta
something to consider is that as 3d printer technology advances and printers have gotten more precise. Settings that once solved problem, are now causing problems, because the problems they once solved have disappeared with more precise 3d printers.
i have a glass bed and for some reason the part sticks so good , i actually struggle to remove the parts ,sometimes the glass will chip and not give up the part , the reason is i use low quality glass from the top of normal 2D paper printers , its so cheap, mass produced and the surface is so bad that 3D prints just stick to it im confident i can print your model probably without a brim , i will try it tomorrow
From what I've found you don't need z hop if you actually level your bed then use the your auto leveling probe, but if you just let the probe do all the work or are not good at leveling your bed you will crash
The failure at 11:12 does not appear to be caused by the nozzle knocking into the printed piece. Rather it appears that the piece falls over while the nozzle is partway through printing the next layer of material there. To me this looks like an either a print speed issue, temperature issue, retraction issue, bed adhesion issue, or some combination of those. But clearly the part wasn’t knocked over by the nozzle during the travel move.
I will be leaving Z-Hop on as it worked fine so far (it's pretty fast and non-stringy on my X1C). I will also be feeling a lot better now, knowing that there's no way to actually solve knocked-over supports and thin parts and will stop trying to solve it in any other way but beefing up the part or support structure :-D
I like the takeaway that if you're trying to use bedhop you probably have other problems (in the design or with the printer) that need to be addressed or better solutions lol.
usefull when you have high areas around edge of some build plates as the X axis sags in the middle, making it possible to hit the sides of the high areas when it comes up from the middle. My printer has a removable plate, that means the bed isnt fixed either, so pressing on to at the edges imparts more force due to lever action, which affects that actual z position on tall pieces.
The bane of 3d printing is the extensive overlap between solutions and problems. It is what it is, but … did you make sure your bed was level?
lol
This is funny. But also true. And it is actually true for a lot of engineering. At least it is my experience. I think it is a sign of a complex system.
@@davidosterberg Definitely! But I don't think a lot of people realize that what they are buying is an engineering problem.
Best problem I've ever bought tho hahaha @@ScottHess
That is so accurate and I am 100% guilty of it. 3D musketeers refers to it as chasing zeros. And I forget I think it was teaching tech. That said, when things get bad just start back over with a generic default profile
I love how you captured one of the most amusing things in 3d printing... how a print can fail, and then.... half recover and start making good layers again on top of the junk is spewed.
I run a small print farm and from my experience Zhop is a great peice in my reliability toolbox. Zhop, retraction, avoid printed pieces, mesh bed leveling and temperature all play a needed part in making sure that I have as few failed parts as possible while printing at 100+mm/s
@@liam4686 not with stock ender 3s.
@@liam4686 you think you could reliably print at 500 and have consistently good quality results?
@@GiovanniGiorgo I sell prints and run at 500 on my x1c. They aren't crazy detailed small models ofc but it's at 500-600mms in abs and is way better quality than my old printers
i print at 350mm/s at 35k without it perfectly
@@liam4686 sure if you've got an x1c or a highly tuned voron v2 but that's not reasonable for a print farm, I don't have $15k to drop on a new bank of gucci printers with untested reliability. I use ender 5+ base printers with btt mobo, bgm extruder and V6 volcano hotends and they are happyest around 150mm/s with 10k acc.
I'm currently looking into upgrading to orbiter v2 with V6 heatsinks and sprite heatblocks with CHT nozzle which I hope will let me go to 200-300mm/s while still maintaining the quality I need. Which when you factor over 12 printers running near 24/7 is a massive throughput.
for me printing in ABS i've found that Z hop saves the print from being whacked over from the inevitable curling that happens on overhangs an arches but thats in air or in a enclosure
Interesting thoughts about Z hopping. Just to satisfy my own curiosity, I decided to try printing the circular Z hop test .STL, with and without Z hop turned on. The printer I used is one of the most underrated printers on the market and is my second cheapest printer, a Kingroon KP3S (US$150) that is totally stock except for the addition of a BL Touch sensor and a PEI flexible bed (smooth surface). The filament I used was a silk PLA made by Tttyt3D (I know, screwy name, but it prints really well). The slicer is Cura 5.4. The Z hopped model was done with 0.4 hop distance, 220C hot end, 60C bed, no supports, and no brim. Printed without problems in about 34 minutes with just a few very, very fine hairs of stringing, mostly on the first 10mm of the model. For the second print I turned off the Z hop and everything else remained the same. Again, the part printed with no issues in about 32 minutes, a two minute savings over having Z hop turned on. The major difference was a perfectly clean print, no stringing at all. Both prints came out flawless as far as surface finish. Another thing to note, the spool of PLA has been sitting on my printer for several months and shows no issues with moisture contamination.
So the bottom line is printing WITHOUT Z hop turned on results in shorter print times and greatly reduced stringing.
Lastly, it just goes to show that an expensive printer doesn't always guarantee quality prints. I've been using this printer for almost two years and the only thing it has needed was a new nozzle.
i use z-hop all the time, and it's quite useful.. from what you've shown so far (TS 00:02:48) Most of your z-hop woes are caused by improper use. you should always "wipe" before doing a z-hop, this lets the built up pressure in the nozzle to be aleviated BEFORE the z-hop, which greatly reduces the blobs and boogers. the scarring you're seeing on your ironing, probably has more to do with your ironing height &speed, than it does with z-hop. Also, you keep blaming z-hop for the stringing, when in fact, most of the stringing issues you're having are due to incorrect retraction settings. the whole point, is to reduce, or eliminate the "oozing" of filament due to back-pressure when you're traveling
agreed
Ozzing is made worse by z-hop. Once you retract and pressure decreases material will still flow out of the nozzle, especially if the nozzle instead of moving quickly to the next colum has to move up then over and then down it takes a longer time where the material can and will ooze out.
@@sierraecho884 That does not happen with proper pressure advance tuning, especially with direct extruders.
@@Penofhell It does because pressure can only be relieved but it does not disappear. Pressure advance tells you what kind of pressure there will be at that curve in advance but pressure will be there no matter what you do it is inherit in the FDM print process. You can decrease the pressure but you can not suck the material back into the nozzle. It will ooze the question is how much. That´s why fast movements are important.
thank you , wipe is the most useful tool in prusha slicer , it completely eliminate blobs and in combination with retraction can completely remove stringing , at that point Z hop is redundant, also wipe can forgive and actually prefers over-retraction
I have actually successfully printed a very similar part. It was a print in place roller bearing for filament spools. It worked actually pretty well, but i usually use PETG and an adhesive for the bed (and my parts usually stick really, really well). Since I use PETG, the viscosity is not the issue when knocking over parts. Molten PETG is more like thin honey consistency wise compared to the toothpaste like PLA. The issues were more with the outermost perimeter being pulled up by surface tension, making these areas higher than the innermost parts. This accumulates until the nozzle touches, then pushes down these areas. This leads to the nozzle slightly wiggling the part until it is ripped from the bed. There is a combination of ways to mitigate this, from extrusion multiplier to finding the optimal layer height - though this will highly depend on printer, filament and the model you want to print.
As said, this seems to depend on printer too. My delta will tends to have issues like this, even with z-hop, while my i3 clone works with just the teeeeniest bit of z-hop and almost never knocks anything over. Levelling and bed flatness might also be a factor to consider.
Advice though: Don't design parts like this, thin pillars just don't print well. If you absolutely need to then use adhesive, slightly under-extrude and use a raft.
This explanation deserves being included in the Bible of 3D Printing by however is to write it. I've been banging my head to understand this phenomenon that happens with certain filaments. Now I need to understand how to overcome it.
Yes an over analyzation video. My favorite!
Channel name fits, doesn't it?
@@novicereloader oh.. reloading and this kind of video fit together perfectly. chasing zeros as another person said.
@@DeagleBingo yep. Tinkering fits certain personality types. RC planes, drones, reloading, 3D printers, woodworking, etc. There's a lot of overlap between these.
I've been using Z-Hop religously ever since my early printing days when I would hear the "grinding" my nozzle made scraping across my print due to over-extrusion. I hadn't thought about the time retraction takes. Thanks!
I agree with your points if you are printing slow. Once I started printing at 300+ mm/s, i needed it on with more complex prints otherwise it was knocking my tree supports off. I will continue to dial in the trees to help see if I can make them better, but for now this setting seems to correct that.
yeah my p1p thinks it's a lumberjack too the way it mows over trees. I ended up going back to regular supports, could never get it to stop mowing over trees and got tired of wasting so much time and filaments. While watching it, I noticed it seems like the slicer don't remember where trees are and avoid them while traveling. At high speeds, trees knock over so easily, even with giant brims. I seen a bunch of times it rips the tree right off the brim.
I went through the rabbit hole of this too and went back and forth between z-hop enabled and disabled for about 6 months now - and since I've got all my other setting dialed in, I ended up with leaving Z-Hop on. Z-Hop *can* harm your prints' quality, but from my experience *only if improperly used* - while it provides quite a few advantages.
If used correctly however - particularly paired with fitting retraction and a well configured wipe move - I end up with much less problems and higher print quality overall.
I tend to argue that it depends a lot on your particular printer model, and of course all the other variables like particularly the type of filament do play a role as well. As stated, with my Ender3 S1, after very long testing I found that it not only improves my print quality, but also avoids lots of issues some prints may cause. Particularly it avoids catastrophic print failures when having to deal with warpy filaments.
When I add z-hop when retracted on my ender 3 s1, stringing is absolutely terrible. I can't figure out how to get rid of the stringing when z-hop is on. Do you have any tips? Thanks.
@@SouthernVaRidin the main variable that causes stringing is the retraction. you'll want to calibrate that to get rid of it.
Given the demonstration on when the print fails, I think a follow up video on techniques like linear (or pressure) advance might be interesting to see if that has anything to do with the failed prints. It probably doesn't have to be z-hop focused, since both settings failed in the same way.
Also, even though I like video, it is not fair to say from this video that z-hop is ruining these prints. This printer/slicer setup is clearly not tuned for z-hop. I and many others get high quality prints and low failure rates with z-hop.
I probably should have been more clear on the process behind the video, which seems to be what's annoying people. I spend typically many days investigating a subject without filming. What makes the video is usually not nearly the amount of work done behind the scenes, it's actually mostly filmed afterwards.
I have tried to work in other ways but it results in too much footage and a poor narrative. I think around three weeks of experimentation went into the findings here, overall.
@@LostInTech3D regardless i think its important to define the problem properly or at least try. in as much as that is what you are doing... that is why i watch. can't figure out a solution if we can't even describe whats happening right?
Actually in my opinion z-hop is a must to have on multi material prints. I often do manual filament changes at the 3 bottom layers to embed coloured text or graphics. As each colour is printed after each other, on small areas the nozzle can kick of already printed layers of the bed. For example if you print an "O" (like on the display case of an "Original Prusa") and print the text colour first, pinting the inside of the O with case colour the line of the O is very easaly touched and caried away. In oposite order (case colour first) the inside of the "o" can easaly be catched away.
So here z-hop (and printing very slow) seems mandatory.
But many thanks, I have not thought about turning z-hop on only for the layers I use colourchange before. I might try it on one of my next prints.
This is what I only use Z Hop for as well. When I do these type of multi-color prints I only enable the Z-Hop for the first three layers and then anything printed above those three layers Z-Hop gets disabled again.
Not sure if this video will stop me from using Z hop, but the info here is really useful and interesting. It could be filament, tuning and such, but I don't see any of the stringing that appears in the video. I'll definitely be looking for some of these situations, especially with smaller parts. One of the reasons I like z hop is when printing complex parts since it does eliminate the nozzle scraping over the part. Moves within complex parts are a different thing than traveling in the spaces between multiple parts. With complex sides, multiple holes, etc. it's not always possible to avoid moves over areas that have already been printed for that layer.
I enabled Z-hop in Cura a while ago because I found the nozzle scraping when moving over infill or solid layers, haven't noticed a decrease in quality but then again my Ender 3 is far from stock anymore. I do notice the Z stepper gets pretty toasty...
For mods I have the dual lead screw belted together with a single Z stepper. I also added thrust bearings at the top of the leadscrew so they turn smoothly even when pulled down.
Edit: I did notice the fluff too, the very light stuff is easy to clear with a lighter thankfully. I might try it without for some prints to see if it makes a difference.
Add some cooling to your steppers. Some people here on RUclips have had success using even PLA to print stepper heatsinks if you don't want to buy one, or you can bend some tubing around them for liquid or compressed air cooling.
(Not strippers, DYAC! There's no paint or poles here!)
@@claws61821 PLA heatsinks! That's the first time hearing that, I guess for low power applications it could help some.
when my print slightly cools it expands a little causing the scrapes. it gets worst when the surface is a large surface area causing excessive drag on the head resulting in layer shifting.
@@Shinobubu i don't know the real solution but you're hitting on the thing thats become the obvious elephant in the room to me. its plastic. literally in the definition of the word. no matter what kind... its still changing shape slightly even after its been printed. and no matter what we have to acknowledge that we are asking this plastic to do two things at once and it can only do one thing at once. heat up and stick to yourself... no wait cool down immediately and don't move! nope. theres a balance there somewhere. only thing i've been able to do to get around this kind of thing is watch closely for when what you are describing is happening and baby step ? is that what its called... the z up a couple thousandths. maybe thats already something that is in a setting somewhere. i don't think its the same as z fade at all. and now that ive said this i'm considering simply adding something into the g code every 5 layers or something that moves the z up just a tiny bit more than what it would normally. if i'm dumb and this is already something i can enable please tell me and i will.
I once had a use case where I had to turn on Z-hop: I was printing TPU patterns onto some fabric on my V-Core 3 500 and the only way to avoid the hot TPU staining the fabric where I did not want it to was 2mm high Z-hop. With the large heavy bed this made for very impressive sounds and visuals 🙂.
Thank you! Thank you! I have wasted so much time and plastic trying to get a model to print without ripping parts loose. After turning off Z hop, prints are successful, not on the ones that worked part of the time, but even the one that never worked no matter what settings I changed.
When printing BIG parts with 1mm layer height, no perimiters and top layers, the Z-hop come very much in handy.
As there are hundreds of places with no or very little bond to the previous layer, the filament curls up and make the steppers skip
I always use z-hop, and I rarely have ANY stringing. Any stringing issue can generally be dealt with through adjustment in print temp, retraction distance, retraction speed, wipe distance, and combing.
why would you use Z hop unless you need it? It adds print time even if you're not stringing
@@user-co6ww2cm9k For me it's the noise, can't sleep with z hop off on big piece
With the FLsun V400, you acctually need Zhop on. Otherwise a lot of prints fail.
The same with the SR
Isn't your model a great use case for a raft? The small base area of each pin doesn't give a lot of adhesion with the bed, and as the model gets wider as you travel up the Z axis, it becomes unable to stay stuck.
Certainly I'd be looking at using a raft if I didn't have much surface area on my model in direct contact with the build plate and had a comparatively large height to print
Actually it would be only if it were not a test print. The whole reason for such a test is to find out if you actually can avoid the towers been kicked by using z-hop. If you use a raft, it wouldnt be kicked in both szenarios, so no use in the test. But of course, being kicked in both szenarios also proves nothing.
In my opinion the test simply has to be scaled down in z. If there is a hight there with z-hop the towers do not fall but without they do, than you prove an advantage of z-hop for this case. If not, this proves z-hop being useless here too.
Thanks for the video. Newer to 3D printing, and went down the path of using Z Hop. It didn't help so much and added stringing every time. The best solution I found was to turn up bed temps during initial layer. For me, this seems to work, and I have fewer failures overall.
Good job finding the cause.
Ways to cut viscous drag (shear force) in half:
1) Raise nozzle temperature by some amount, which you already tried.
2) Double height of Z-hop.
3) Half the travel speed.
4) Double the layer height.
5) Without reducing layer height, select a 0.3mm nozzle instead of a 0.4mm nozzle. Also, the tip should be narrow and pointy, without a large flat surface for ironing.
Of course, the problem with most of these solutions is that they increase the time and/or tendency for filament to ooze from the nozzle during the travel move.
I was very surprised to successfully print this on the first go with no issues... Ender 5-S1, out of the box... No z-hop, 0.4 nozzle, 0.2 layer height, 120mmps, no raft or brim, single skirt, 3D-LAC spray on the bed (as always). 35min print time.
Minor wispy stringing was the only issue... I posted my make on your printables...
Cool video and certainly got me thinking about my printer's capabilities.
I also printed Angus's @MakersMuse Clearance Castle and the torture toaster with perfect results and all clearances are free moving.
I feel like the 5-S1 has taken the skill out of 3D Printing as this was surprisingly straight forward.
I discovered such stringing myself with z hop as well. And took me days to figure it out, by literally staring at the print as it was being done to see that that little hop carries the smallest amount of already laid down plastic with it. Luckily, in the end it got me to realize my belts were too loose anyway.
This is a brilliant video! I think the kind of " sticky " nature of molten plastic is like really overlooked and is such an important concept that in some cases it even prevents some prints to finish!
i feel like he's found why this happens for this model. at these settings... at this nozzle size... and with this filament. and imho this naturally should lead us to consider the physics of the plastic itself as it cools (which i am NOT saying i understand at all btw). which i think is what pro level 3d printer mfrs sellling 10k+ units to engineers have done more of. the fact that as the print cools down or does whatever it does in whatever specific circumstances... changes the way it reacts to the "drag" of the viscous molten material pulling as the nozzle moves... imo there's no getting around the fact that no matter the glue or bed surface that the bed adhesion itself changes over the course of the print time. its something i keep noticing no matter what i do. none of the printers we use as consumers ... and maybe none of them in existence even... can completely control all the variables. and a different astute commenter made the great point that these variables we try to alter all seem to overlap each other to a certain extent too... obviously enclosing the area is better, having it stick down harder to start with helps... etc etc etc.. even then my understanding is that all plastic still warps or contracts/changes shape as it changes temperature. so until we can have some way of like... i dunno.. printing a ledge that then gets clamped down to the bed, or theoretically screwing the print down to the bed from the underside or having some ideal situation where the stuff is a heated liquid only when it needs to be but then is immediately cooled to room temp solid once its put where it needs to be that we're always going to be fighting adhesion or subtle changes in the shape or size especially with any models that have small contact patches like this one that he made.
Most of my prints are small parts, 6mm diameter cylinders and up, and others of various sizes. The filament varies depending on the end use. The range of plastics is Nylon (Taulman 910), CF-Nylon(Different manufacturers depending on what nylon content.), PCTPE (Taulman), 75D TPU (NinjaTek), 95A ( NinjaTek, Sainsmart), 95A (Overture - a little softer than the other 95As), PETG (Oveture - over 200k used), PLA (Rarely used).
The key element to successfully printing small parts like you were testing is to print them sequentially. I have been using this strategy for close to five years with a very high success rate, close to 100%. Granted, you don't get as many parts per build but the fit and finish, and the strength are near perfect. Oh, and your stringing between parts is close to zero. I also keep my prints under 3 hours.
Prusa Slicer 2.6.1. No Z hop and very low retraction. Avoid crossing perimeters: setting.
I also use Garolite to print almost all of these filaments. I use gluestick for the nylons and Aquanet hairspray for the TPUs and PETG, More as a release agent than for bed adhesion.
I hardly ever need a bring on the smallest of parts.
I'm using Prusa MK3S and Prusa MK2s.
I use Z-Hop when printing thin multi colour parts, such as earrings. Enables me to leave each part on the plate and fill in the gaps. Z-Hop at about 1mm for 0.5 - 0.9mm parts.
I had a print that was consistently giving me severe layer shifts at one point in the print. This was after switching to flashprint from flashcloud for slicing. This piece had an overhang edge the slicer was moving past and hitting with the head. I have a textured build plate with truely awesome adhesion. Rather than dislodge the part it was shifting the build plate a bit and/or making the stepper motor skip steps.
This was fixed by turning on z-hop "when crossing part edges".
In retrospect perhaps the default 109% extrusion rate was also contributing. Calibration tests since then suggest this is excessive for part dimensioning, but definitely helps with layer adhesion.
I was doing a print that had a fair amount of tower supports. Afraid the print head would knock over a support, I turned Z-Hop. Every time, the print failed. When I was re-slicing, I accidentally turned Z-hop off and that print was successful. Two other settings I found useful for the quality of the print is Z-Seam Alignment and Infill Start Point both set to Random. This prevents a single seam line to be visible on the piece because of the print layer starting in the same place every layer. Same goes for the infill start point. "Random" is your friend!
In my experience, my parts were failing. When I was new to printing, I switched from Z hop OFF to Z hop ON. I never had a problem since, nor have I changed the setting. Good results, clean ironing. I set my printer to print at 60mm/s. Biqu B1, stock. No catastrophic failures. I'll experiment. But as for those pins not sticking, I'd use a raft. If nozzle hits, have to reassess. I need functional parts.
I usually print initially without it, and if there are problems I give it a try and use the version that works better. There were maker videos here about 2 years ago that were fairly thorough as well showing specific cases and printers that Z-hop fixed the problems they were having, particularly with stringing iirc and ironically enough. Combining the 2 thoughts together I would imagine that improvements in slicers and printers and print surfaces have changed the playing field. Ive learned over time that when changing some variable of printing there are almost always at least 2 other variables that need to be considered, its almost always a 3 way problem or more. So with each modernization we'll have different settings that need to be adjusted.
In my experience, filament is not viscose enough to overcome bed or layer adhesion. When filament viscosity causes a part to fail, that is usually because the part has already partially failed earlier, e.g. the printhead already bumped into the part in an earlier layer causing the part to break, it just didn't fall over yet.
Most of the time Z-hop isn't necessary. I think the time I've needed it most is when I don't have adequate cooling in combination with thin, steep overhangs; that's when the most extreme curling will occur. (You should have seen the prints on my first kit printer that had NO cooling. Curling was a huge struggle, as was warping on long parts on the non-heated bed. I'm having PTSD thinking about that.)
Generally, speaking, however, you are right about it just causing unnecessary stringing. Being that I forget to turn it off, it's probably why some of my modified PLA (so-called PLA+) filaments will string like heck.
I agree on this. Z-hop seemed fine, but in all my prints I had issues with it - and it does add a bit of time to each print, every up/down time adds up over the hours of printing after all.
there were some attempts to turn Z-hop into a V shape, so it retracts, moves both over and up at the same time, then back down while still moving over, and then begins to print again as well - which seems better for the time loss, but still can leave unwanted melted spots, and the issue of vicious melted filament sticking and instantly connecting and being cooled to harden - then causes 'grabbing' and can move/destroy parts.
better part cooling exists now too - which helps that curling effect go away.
Hello, I've been using Z-hop since I started with the Sidewinder X1 and it has definitely solved the problem you mentioned. I've never removed this setting again because, after checking, it doesn't save me any printing time or very little, which, compared to having to start a print again, isn't worth the risk. On the other hand, I don't notice any deterioration in my prints, they come out clean and without the stringing you have on the prints you show us, perhaps a setting on your own printer is to blame for these filaments because on the X1 I don't have this phenomenon. I've downloaded your model, and I'll be testing it soon (if I don't forget) with and without the Z-hop, whose height I've set at 0.125mm so that the nozzle no longer touches other parts of the part being printed. So if I don't forget to do the test, I'll come back and report what I find with and without the Z-hop in your file.
Your channel has helped me more with troubleshooting 3D print issues than any other. Thank you.
Slow motion wobbling of bed slingers rocking up & down definitely shows where a lot of high-speed contact can occur when the bed have large travels.
Seriously man you're over thinking this way too much. Z hop is not the issue here, barely sufficient bed adhesion is. If you have no oozing, good pressure advance and a very fast printer (including Z), z hop basically has no disadvantages and it solves a few unlikely failure modes, namely hitting a small corner area that curled up and is thus sticking out.
I was just going to say the same thing. The test is flawed. ZHop is not the issue, the bed adhesion is the bigger issue with the pin ZHop torture test.
Also the claim that ZHop doesn't prevent scarring is not true either. With it turned on and also combing for me in Cura set to off I don't get scaring of the top layer anymore.
And the fine whisps of stringing, that could honestly be retraction settings or depending on the material being used may need to be put in a filament dryer box.
Point being, putting all blame on one thing is wrong. It's more likely several other things could lead someone to believe it's only one issue when they're not looking at the entire scope.
So I simply _had_ to turn on z-hop while using prusaslicer because every time it would move over the tree supports (i haven’t had a single print get knocked over due to nozzle travel since, though I have run into that viscosity issue you mentioned), it would knock them over and fail the print. I honestly don’t care about the stringing because a heat gun easily takes care of anything like that and produces a perfect print.
Great video! Personally i will be leaving Z hop ON when printing multiple parts(with collision avoidance aswell jic). In Cura, using it with COMBING MODE "not on outer surface" gives me amazing results with good top surface finishes. Zhop has to be configured correctly to get nice results, i have it raise 0.7mm and 40mm/s - faster means minimal stringing and it never hits printed parts off the bed or misses steps because of a collision...
Finally one more thing to concider is filament ooze - could it create high spots while moving over parts (with z hop)? Most likely yes - in my case tuning in Linear Advance to eliminate ooze helped A LOT with parts getting knocked off.
My biggest issue in Prusaslicer was that the 'equivalent' settings, 'avoid crossing perimeters' and 'avoid curled overhangs', decidedly did NOT avoid crossing supports. This cause me big issues during the 2.6 alpha, because all those shiny new organic supports had a tendency to get sideslammed and that amount of torque on either very tall or very thin branches would very quickly cause them to fail, and I'd be lucky if the failed support didn't take the rest of the print with it. I'd be curious if the higher temperature idea would work in my case, but zhop was a simple fix to the problem at the time. Honestly, I wish there was a was to identify a surface or object (like supports), and specifically enable zhop when entering that specific area.
Love this vid and recommend it fairly frequently. Would be cool if you added chapters.
noted!
V400 here...bed adhesion is essential when printing high at high speed. Make sure your print can't get knocked over. Hotter extrusion, better cooling all helps. A hotter nozzle will also just go through the old layer instead of hitting it.
when i discovered combing i turned off z hop "not in skin" being important for the quality finish.
I need to cover combing....good call
z hop helps mitigate the nozzle dragging across infill, since cura overlaps infill lines at crossing points giving them virtually 200-300% extrusion right at the crossing, which causes it to get raised a bit and without 1 layer of lift it usually drags. the fix would actually be to not overlap those infills but ultimaker couldn't care less (it's the only reason ive gone from cubic subdivided to gyroid, its worse but when going at 250mm/s cubic tends to grab the nozzle so hard it skips steps and ruins your print)
Ohhh...that makes sense!
I need some infill lore- why is gyroid worse?
I remember the community post with the question! Thanks for the great research, it's much needed. It's really hard to convince people that what they're observing might be affected by concurrent causes when discussing any parameter.
I never use Z hop. I use thick layers of purple glue for adhesion, then remove with ultra thin artist pallette knife if it sticks too well. They pop off effortlessly with those. I think those are essentials for any printing enthusiast!!
Tried to make that model of yours. Printed fine with or without the Z-hot. Though of course, Z-hop had a lot more stringing.
For reference:
Creality Ender 3 V2 Neo
Modified with hardened glass bed and direct drive for Ender 3
Steel grey PETG from C-tech
0.12 mm layer height
standard 0.4 mm nozzle
50mm/s printing speed
Full infill
no supports
230 C nozzle temp
80 C bed temp
I've never used z hop ever.
I print articulated figures that requires printing multiple small parts.
I've dealt with issues mentioned above and for me the biggest game changer is part cooling. It'll help with dialing in your retraction, tempreture, and help prevent stringing and curling of overhangs. Some useful slicer features to further help with these problems is the per model settings in cura. I could set a slower printing speed independently for some tall, norrow parts that are prone to failure.
Stay away from z hop specially if you have an old ender 3 style printer with a single lead screw.
Try printing a larger print with a lot of infill - that's where zhop has saved me.
I only have z hop enabled for the first two layers as that's where my bed adhesion tends to fail if it's gonna fail
ABS is shrinking more than PLA or PETG and it will curl up. Z-hop of 0.4 mm definitely helps printing ABS, when your toolhead whizzes at 160 mm/s speed and 300 mm/s travel moves. You have v0, you can easily tune it to those speeds, load up ABS and try yourself 🙂 If you think Z hops are slowing you down, you can do Z on belts - CoreXZ, flying gantry, belted Z mods.
printed the pins in circle n ABS no brim without any problems, took about 24 minutes.
printed with 0.1 mm z-hop.
came out fine.
Machine: Voron V2.4 R2 stealthburner with LGX-lite extruder, klipper
Yup, Z-hop was a massive issue for me. I turned it on in the beginning when I had some other issues, causing filament to curl up, which the nozzle then ran into, ripping the print off. Z-hop fixed that issue, but caused SO many other issues. With more experience, the other issues I experienced were fixed with better designs, better bed adhesion, better leveling, etc., so Z-hop did nothing but hurt my prints. It also massively increased stringing in my case.
Tried the "unprintable" on my ender 3 pro, the surface was a bit rough but it printed succesfully the first time, ASA filament, no Z hop, sliced with CURA with skirt, no brim, printer is a bit modified, V6 all metal hotend, print bed is coropad on a spring steel plate, SKR board running marlin, linear advance, ABL, and a closed enclosure (heats up to about 35-40C from the 90C bed temp)
Also, you're using silk filament for those pins, which is WAY more viscous than regular non-silk PLA. I'd be curious to see a comparison video about THAT
yeah I was hitting it hard with my worst filaments, to try to cause extreme issues. It definitely would be a good video, but if this one is anything to go by, it will be....uncooperative
I use Z hop for tall, narrow pieces where any nozzle bump may cause a failed print. Strangely, and seemingly counter intuitively, when printing with materials that have poor bed adhesion, the "pulling" effect causes it to unstick from the bed and makes it more likely to fail. When I /do/ use Z hop, I tend to use a pretty high hop, enough to make sure to break any ooze, usually 2mm.
Man, Z hop was disabled by default on my printer. After one particularly difficult print kept failing I found that and enabled it, and solved a TON of other issues as well! SO MANY problems are caused by the nozzle just barely grazing the edge of a print as it moves around and throwing off the alignment and Z hop completely removes that issue. (With Cura and a Ender 3 Max Neo)
But all of these settings interact...and unless you're spending half your time on just calibration prints you're not going to get everything perfect. Maybe Z-hop is easier for you; maybe you'd rather spend a couple hours dialing everything in to hundredths of millimeters of precision...all depends on what you're printing and why. For my own use case, z hop is excellent.
Setting up z-hop correctly with the right height and retract values has done nothing but improve the success and quality of my prints. I highly recommend giving it a shot!
Grrr... twitter banter bedamned, I had to give you a thumbs up for this video. Well researched. Thanks for this one.
Hahaha thanks
Checked last night if you had a new vid out and I'm starting a print as I see this notification. 😂
Interesting. You could see thru the brims on some of your prints, like gaps between the layer lines. Maybe more squish would help. Otherwise you should have used a RAFT.
On certain printers like Voron 2.4 that have belt driven Z for the exact reason of having extremely fast z-hops I think it does not apply as much. I may need to do some testing but from the printing done so far it looks like with a very fast Z move it actually helps break the plastic string and works reasonably.
Interesting video, but completely opposite to my experience. On my Biqu B1, Z-Hop eliminated the nozzle knocking over curled up PLA overhangs. On my Bambu Lab X1 Carbon, Z-Hop is on by default and has never been an issue (temperatures are set a bit higher than normal though). I also never saw any additional stringing in PLA with Z-Hop enabled (to me, stringing is more indicative of wrong temperature or retraction settings).
Thanks for your info. I wasnt sure z hop really helped any way. but with printers going faster the knocking over is going to be alot more common. i think a reall indepth analysis on thhis is sorely needed, to find whats going on. very informative video, great job.
Like others in the comments have said, poor retraction is the cause of the stringing. I had Z-hop woes when I started 3D printing where having it enabled would cause missing outer walls and other weird problems. It can also exacerbate stringing and branching if retraction isn't tuned right.
Turns out, Z-hop causes that if it lifts up too fast, too far. Generally it should be equal to or less than your layer height.
I find Z-hop very useful when printing delicate bridges and overhangs, like on E3D's Spider's Web stress test. The print almost always fails without Z-hop.
I have Z hop on almost all the time if the print needs supports, because no mater what i did i would hear scraping on the infill and i would often come back to a printer 10 or more hours later to find that one or more of the supports had been pushed over and the print failed, however if all you are printing is a flat object or something that does not need supports then it is not needed. There is no real disadvantage yo having Z hop on as it completely removes the possibility of the nozzle striking the print or support material, people often say it considerably increases print time which is false because if you like my set up have it set to twice the layer height so 0.4 but then dial up the speed of the Z hop it actually adds a very small amount of time ( about 22min on my last 12 hour print ) as for the stringing you experienced looks like a profile issue ether you are running to hot or your retraction is not set correctly or a common error people make is not turning on retraction during zhop
I 3d print for architecture and zhop is pure gold. Many Overhang cause curl edge which zhop prevent nozzle from hitting them and fail the print.
If hop is off, the nozzle may wipe itself on the print as it moves. When hop is on, you should wipe before the lift to eliminate the stringing. I have wipe+hop in the profile I use.
Agree, I mostly gave up on Z-hop, even small hops cause stringing, which is not a big problem actually, but Z-hop doesn't bring much to the table
Z-hop is exactly a safety feature that's turn on by default as it slightly increases the chance of success of prints. It may result in worse quality, but it eliminates the knock-over concern. If you have a fine tuned file and printer it's not necessary to have Z-hop, but manufacturers keep it on as it lowers frustration in general for most people.
No matter what I did I couldn't stop the nozzle from catching on the infill and making that noise so I opted out to use z-hop. That 'grinding' isn't really problematic most the time but sometimes it can move a part slightly or knock it off. I really did try so many things to change that and I mitigated that grinding but I couldn't get rid of it. Maybe it's related to the manufacturing of my printer, who knows.
My Ender 3 V2 came with a faulty board as well, so that was fun... I thought changing it would fix everything but that particular thing wasn't fixed.
I guess this is mostly per-printer or per-user preference since z-hop has its upsides and downsides. If you can't help it you use it, if nothing works use it.
I have not found any reason to use it as long as my machine profiles are dialed in properly. I will occasionally run z-hop on tricky TPU prints... But, I pretty much agree with everything said. Lost In Tech, thanks for another great video.
I just sliced and printed your impossible file and it printed fine.
Bambu lab x1carbon, bambu studio slicer, default pla settings and there is a z-hop.
1 wisp of stringing and some minor droop of filament on the 90 degree top/curve.
I won't use Z-hop very soon, for the parts I print (rotors, bigger pieces) it's useless. I was also wondering and blaming filament for the "cotton fluff" stringing. Useful video! Thanks!
Later edit: I just did disabled z-hop and it was the missing piece that caused imperfect prints. The differences in my tests were more obvious than shown in this video.
I miss the tests done with PETG. Since the viscosity is a lot lower with PETG, it might have a usecase there.
Doesn't PETG have a higher viscosity?
Z hop helped stop my prints being moved by the nozzle hitting the prints, since then I’ve had success with every print.
Materials that collect on the nozzle when travelling, like PETG, will accumulate, cause blobs to forum, and fail the print when crashing into the blobs. "wiping" the nozzle (with out Zhop) increases this issue. if any portion of the print has over extruded( like sections of solid infill), this will be even more important to avoid. In a perfect print, where you never over extrude even a tiny bit, then you don't need Zhop. The more solid the print, the more needed zhop is.
I turned on this feature as it is in Prusaslicer and it solved a lot of issues I was having with prints getting knocked over or nudged
oh boy glad yt algorythm showed me your video. I was struggling with printing things and now I changed the slicer but maybe its zhop. I will test it with what I was printing and your torture test.
IF using Z hop to prevent gouging, I've found it a good idea to engage 'wipe' function in Simplify3D.
This combines with the retraction to clean the nozzle and prevents stringing.
I never use zhop, mostly because I believe that the issues that cause prints being knocked over are indicators that there is a problem with the machines tuning, and I can usually fix the issue and have good prints again with a little troubleshooting. Any setting that doesn't make the fact that there are issues with the print obvious is a complete no-go in my book. Not everybody wants to deal with every problem if they don't absolutely have to, but I would suggest eventually dealing with all printer problems if you want a better long term prints.
disabling Z hop except for first and last layer in Orca Slicer completely fixed my horrible stringing issue. It went from a string connecting every layer on a tower test to absolutely zero strings.
I agree Z hop is not always a good thing. but I can say that if you have a model / structure that has a 45° or lower angle (from the print bed) the last layer will have a small amout of it with no support and this will curl up and when the nozzle comes back from and other area if it aporaches direcly twoards the little curling up lip from the edge you will get a collision and this may knock the part off or cause some astifacts in the layers.
I just printed the test on an FLsun QQS Pro, using cheap PLA and default settings in Cura 5.3.0, without any problems, just a tiny bit of stringing between the pins.
Bedslingers: On
Corexy: Off (since bed does not move back and forth)
Your print might have failed on z-hop since the base had little support. The nozzle basically picked it up on the way.
I don’t understand why people struggle with build adhesion. 1. Make sure your nozzle is set to a height that the first layer is correct, it should be smooth, not spider web looking. 2. Glue stick every time, period. 3. Keep the bed at 60 degrees (or whatever your filament recommends). Use a skirt to prime the nozzle.
1.5 years of printing and I’ve had exactly one print fail build adhesion and it’s because I forgot glue and it was a 15mm scale apartment building so eventually it got in the mood to dance on the build plate.
just came here by chance. you nailed this. this took me a month to figure out a few years ago lol
I bet the hot end shifting on the roller bearings is what actually happens. When the filament sticks, it's enough to shift the hot end to the extent of it's backlash. Then the nozzle collides with the part. It would be interesting to see this in super slow motion and macro.
that thing will certainly be one of the things i print once my printer is rebuilt
I see in your example of the Zhop stl that you are using Cura
Try these 2 changes
Uncheck avoid printed parts while traveling
Cut your travel avoid distance in half (0.312)
It's not always about more clearance when traveling
I've found regardless of which slicer I'm using (Cura, Prusa slicer, Bambu Slicer, Orca slicer) that sometimes slowing things down and adding more travel clearance to avoid things like stringing, blobs, lines on outer walls, and general adhesion issues causes the Slicer engine to add extra or certain unnecessary moves which makes things worse and can be very frustrating
Not to mention, there is no single group of settings that will give the best consistent results for every model
Z hop and retractions are excellent tools but must be kept at a minimum rather than a maximum
For 99% of my prints infill combination is selected and my line width for the infill is the exact value of the nozzle size I'm using where as my walls and top surface on say a 0.4mm nozzle are 0.42mm to 0.45mm depending on the size of the model with a layer hight between 0.12mm to 0.25mm
That's only one example using Orca which I'm now using on my 3 clapped out bed slingers and my X1C
I'm still on Orca 1.6.2 but will update once the latest version comes out of Beta
something to consider is that as 3d printer technology advances and printers have gotten more precise.
Settings that once solved problem, are now causing problems, because the problems they once solved have disappeared with more precise 3d printers.
i have a glass bed and for some reason the part sticks so good , i actually struggle to remove the parts ,sometimes the glass will chip and not give up the part ,
the reason is i use low quality glass from the top of normal 2D paper printers , its so cheap, mass produced and the surface is so bad that 3D prints just stick to it
im confident i can print your model probably without a brim , i will try it tomorrow
If you're printing in PETG, it actually does stick spectacularly to glass, as if they were one and the same.
From what I've found you don't need z hop if you actually level your bed then use the your auto leveling probe, but if you just let the probe do all the work or are not good at leveling your bed you will crash
The failure at 11:12 does not appear to be caused by the nozzle knocking into the printed piece. Rather it appears that the piece falls over while the nozzle is partway through printing the next layer of material there. To me this looks like an either a print speed issue, temperature issue, retraction issue, bed adhesion issue, or some combination of those. But clearly the part wasn’t knocked over by the nozzle during the travel move.
My Craftbot + printed both perfectly. Mirror bed, 3D Lac and Zhop on. Was no problem at all.
I will be leaving Z-Hop on as it worked fine so far (it's pretty fast and non-stringy on my X1C).
I will also be feeling a lot better now, knowing that there's no way to actually solve knocked-over supports and thin parts and will stop trying to solve it in any other way but beefing up the part or support structure :-D
I like the takeaway that if you're trying to use bedhop you probably have other problems (in the design or with the printer) that need to be addressed or better solutions lol.
usefull when you have high areas around edge of some build plates as the X axis sags in the middle, making it possible to hit the sides of the high areas when it comes up from the middle. My printer has a removable plate, that means the bed isnt fixed either, so pressing on to at the edges imparts more force due to lever action, which affects that actual z position on tall pieces.