Yes! Keep making these 10 minute detailed build guides. So helpful when understanding what all is needed and how the process of each build step should go. Great job.
Yes 100%. I enjoy the live streams, but they can be very hard to find specific information. If I am looking for how to make the build plate, or assemble a specific part it sucks scrubbing through 2 or 3 hours to find info. These concise videos are great.
When you attach the ground wire it’s a good idea to put a shake proof washer between the ring and the plate. The teeth on the washer bite through the thin oxide layer on the aluminium to make a better contact.
@@joshua43214 I dunno. The plate is for a Voron, where it won't be moving at all. If the plate was moving along y or z, then yes, then protection is mandatory. But in a Voron, the cables will not see any movement what-so-ever.
Nice video, thank you. I'd like to mention (albeit 3 years late,) that the thermal expansion coefficient of aluminum is unaffected by its manufacturing method. Aluminum has around a 24x10^-10 TE coefficient. So the claim that it doesn't expand is not true. Other than that though, great video. Ty
Small correction in terminology: In electronics, when something "fails open" it means it fails open circuit. I.E non-conducting. The two fail states are described as failing open and failing short. Failing open is the safe one. Your use of "fail open" is the one applied to water valves etc, in that when they fail open, they fail with the valve open.
Hey fellow Canadian! Because you are making an electrical connection to aluminum (the ground connection), best practice is to use electrical joint compound between the crimp and the bed to prevent possible future corrosion. Aluminum is highly susceptible to oxidization, especially when in contact with dissimilar metals. We call it Penetrox, but there are other brands available. To be clear, it is not dielectric grease. Love your videos, by the way. I credit a lot of my success with my current build to you, haha
Oh that's a good point. I have some no alox stuff I use when I have aluminum wires landed in an electrical panel, I should put a little on my printer bed ground!
Just for clarity, are you sugesting to apply some compond inside the crimp? and would this apply for all crimps and ferrules that would be used with the copper wire inside a printer build? you suggestion has raised some alarm bells in my head....
One thing to mention about connecting the fuse: Solder joints work perfectly well at mains voltage, and even voltages above that. However, they are low temperature welds, and heat cycling at the 100°C that some filaments require would cause problems long term. I disagree with your usage of automotive crimp connectors, as manufacturers frequently don't certify them above 24V DC, and even lower voltages AC. I'd suggest instead using what electricians use: Mains insulated screw connectors, or Wago-style snap connectors, along with ferrules. They are intended for use in house wiring, and thus support both the voltage and currents you need. They also have the added benefit of being simple to disconnect if needed. If you were working in a factory, waffle iron and coffee maker manufacturers frequently use solid core wire (as well as thermal insulation you wouldn't need for this application), and spot-weld it to their in-line fuses.
It would be good to see a thermal camera view of the bed when in operation, especially at higher operating temperatures to emphasize any gradient. I would expect that a major effect in warping would be differential heating and thus expansion of the middle of the bed compared to the periphery. The middle would expand but yet be constrained by a less-expanding outer ring, inducing a bow up or down perhaps. For this reason, I think it would make sense to insulate the exposed peripheral inch or so of underside, so that at least that outer area loses less heat and would come up to a temperature more similar to the middle. If in practice a bow is not seen, then it would still be informative to see the heat map to learn what amount of temperature drop-off at the edges failed to produce a bow. Of course, these considerations are not particular to the bed discussed here, but as long as we're getting all sciencey on this one, it would be great to see how these variables play out!
There a photo of my bed plate (8mm cast tooling plate, 300x300mm) here: 2.bp.blogspot.com/-PASdLoJVJes/WZO-mOZF3-I/AAAAAAAAGpY/xY3oYLw1KM4gSspIzeLgnmpytTdFPzeIwCPcBGAYYCw/s1600/UMMD%2B105C%2BFLIR.PNG The heater is 300x300 mm. I would not recommend using a plate that bigger than the heater (like this video) because the edges will be cooler than the center which will lead to warping when heated.
For a cast aluminum plate, that's right: Any warping would probably be a consequence of uneven heating. For an extruded or otherwise formed plate all bets are off - those can have residual stresses that cause them to warp even when uniformly heated.
One thing you *REALLY* *NEED* is to protect those wires from the edge of the plate. Use properly rated heatshrink you get from a reputable supplier (the local big box store is fine). You want the stuff that is used in mains wiring. It will be expensive, and really thick. Do not not imported stuff unless you know for a fact the certification has not been forged (all the inexpensive stuff on Ebay and Amazon are probably forged certificates). A single layer of Kapton tape should be under on the bed that comes up over the edge under wires is secondary protect.
It's not ideal, but it'll still reach a steady state not much lower than the heater. At least with some insulation if the heater overshoots on heat up by a bit it won't trip the fuse unless that overshoot persists a decent amount of time.
I love the Voron plate! Is this the first Voron-themed plate you've used? Also, is there any particular reason the PEI sheet isn't yellow? Is this a special high-temp thing for Toasty Boi?
Oh boy I didn't know I had such an amazing store as Fermio labs so close here in the EU. Absolute chads. Thank you again Nero for sharing all this awesome knowledge. Makes too much sense that such a thicc plate is super stable thermal wise!
Me neither! I was already happy to find out that Filafarm was selling thick plates and they are also based in Germany. Great to have both options available.
Take from a person that did this 5 years ago with a MIC6 Plate.... I highly recommend mounting it on springs so it can expand/retract and still maintain Z = 0.. even with tight PID heating, you'll get artifacts as that large plate expands and retracts with heating/cooling. With BLTouch and mesh bed leveling becoming a thing, it got rid of the need to have a high tolerance flat print bed these days
I run mine mounted on both my v2s with a basic 3 point fixed mount. And even after years of use im still able to get by without a mesh as the surface is still flat enough
@@CanuckCreator thats not what i am saying. Fixed mount will cause what looks like z wobble artifacts because your fixed plate is expanding and contracting. It is made worse because of how thick your plate is. Springs allow the plate to expand downwards and maintain z=0. The mention of mesh leveling is that flat tolerance of MIC6 is not even needed anymore and hasnt been for years. Hence why no one bothers with cast plate anymore.
@@ShadowRam242 To be clear, if the build plate expands downwards, should we infer that the mounting consists of flat-head bolts countersunk into the surface of the build plate, with springs pushing up from the bottom? So your confidence in the build plate fixed Z height is because the top surface is "held down" at a fixed Z height by the bolts, right? This assumes (a) that the bottom of the bolts' countersunk heads are close enough to the surface of the plate that the height of aluminum above them is negligible, and (b) that the bolts themselves do not expand and contract with heat. Both of these may be valid assumptions, but I just wanted to see it spelled out.
@@ShadowRam242 It's not that it hasn't been needed for years rather it was more expensive to get plate and have it machined and chinese 3dp companies did not want to eat that cost. I did the same thing with the CR-10 in 2017 and the Wanhao D6 came with a cast plate. There are people that were building cast plate beds prior to 2014 and they used 3 point leveling.
Does anyone ever apply magnetic sheets or any of these adhesive items like window tint or automotive decals where they use windex or a soap solution to lube the sheet to allow for moving it around and removing bubbles and then when it all drys it is all flat?
So, I did this install about 2 years ago. Last night I rewatched the video - after noticing my bed was bowing and i coudl press it inwards around the center (kind of like my own stomach) - turns out the adhesive was failing, and the RTV held the edges quite solidly. THANK YOU. I don't know how close to a house fire I came (if at all) but I'm incredibly grateful for the RTV tip. As I now await my new heater.
That was exactly the video I needed as I have a similar thick precision print bed kit from Filafarm (based in Germany) sitting here waiting for installation. Various print projects keep me from finally starting with the installation and I'm also no electrician so I was slowly gathering all the knowledge needed to do this safely. Your video nicely summed up all the bits and pieces I found across the web including some tips I didn't see elsewhere (like the extra heat resistant silicone around the heater mat). Btw. my heat protection fuse is not a cased variant like yours but instead looks more like a basic transistor. Are there advantages to the one you use?
I was interested if the gasket glue is could also release a kin to the 3M adhesive which is holding the fuse. So a possible overkill could I run 2 fuses in series. One attached to aluminum and screwed that other stuck via gasket adhesive to the heater mat. Or is that really overkill.
Couldnt find tooling plates, so I do mines with 3/4in (20mm) plates. Nice thing is I can drill and insert the heater core in the plate so I can add more if needed. Thermal fuse is really important, I had a relay sticking and the bed when up to 280c the whole night. Came back to look at a pool of petg and 75$ of wasted magnets.
something to maybe consider.... if your thermal fuse falls off as heat rises and then it loses the protection it was designed for..... There is usually nothing under where you mounted it to catch it... Maybe best to use Both a bolt on one And one as you have? being mindful that many follow you and print when not home and overnight? cheap insurance? NOT being the fire chief just a observation... Rock on man your doing a great job!
I find the discussion about "cast" aluminium plates very funny. I worked in a aluminium factory as a young engineer. Every aluminum plate starts as a cast block of alu. That is then rolled into flat shape. It is then heated up to 460 - 560 °C to homogenize the crystal structure in the metal. So actually if you buy a rolled piece of aluminum that was homogenized it is more stable for bending when heating up or cooling down as a not heat treated piece of really casted aluminum.
@@vinnycordeiro I don't work in that area for over 25 years now, but it would not make sense to me to use a complicated process like extrusion for a simple flat slab of aluminum. Especially as cutting a generally available slab of aluminium is much easier with minimal waste. Extrusion is a complicated process that requires complex machineries and therefore commonly used for profiles that cannot be produces in another simple way. To me that hole "casted bed" just sounds like a new buzzword to rip off people. But that is my opinion.
@@Empusas1Goto Alibaba and look at how the factories are making their beds and you will see why there are so many problems with cheap rolled aluminum beds.
@@Deneteus Lot to unpack here. First the properties of aluminum depend mainly on the alloy used. There are many alloys used today for different purpose. I doubt that you can find a 99,9% aluminum plate. For rolled plates, foils etc often used alloys are AlCuMg, AlCuSiMn, AlMgSi, AlZnMg and AlZnMgCu. The same type of alloys is used for aluminium that is rolled, extruded or cold forged. Every time you mechanically change the shape of a metal object you get tensions in the object and distort the natural crystalline metal structure. To remove those tensions there is the process of homogenizing that I described before. In additional those alloys can be hardened by heating them up to 120 -175°C for 1-2 days and let them cool down in a controlled curve. You may look up duralumin for more. For castings different alloys are used like AlSiMg, AlSiCu, AlMg, AlMgSi, AlCuTi, AlCuTiMg. Those are not suitable for any extrusion or other mechanical reshaping as they have a natural hardness that would let the parts break or crack. Those either casted into the final shape or a blocks of aluminum that are cut into slabs and/or milled into shape. So the alloy defines how the block of aluminum can the processed into the final shape. It is true that there are companies that sell slabs of casted aluminum for special purpose like the company "Gleich" in Germany for example. They also heat treat the aluminum block to homogenize them before the cut them into pieces. There is video about the process shown here: ruclips.net/video/HBvVleIO75A/видео.html different
@@Empusas1 I like how you went on a tangent when i never said anything about alloys or 100% aluminum plate. I said the word cheap. I am already aware of everything you just said. That doesn't change the fact they are cheap and typically attempt to return back to their original shape over time when heated.
Great video! I'm currently building a V-Minion and I just did the bed based on this tutorial. I'm just missing the silicone gasket seal. Any tips of what to get in Germany?
Very nice video. No need to insist on cast alluminum tho.your printers frame tolerances are way higher then difference in warping between cast and rolled alluminum plate.i bet if you could scan frame and compare diagonalls othey would be off by 2 mm for shure. Also you glue on top magnetic sticker and put up spring steel sheet. So ...
What is the difference in heatingtime at 12v, 24v, 48v, 110v & 220v silicon heater? I want a silicon heated bed but i am a bit hasitant to put 22v on my printerbed. I was thinking about a 48v silicon heater. So can anyone tell me what the heatingtimes are of theese heaters?
I believe my SSR failed, the light no longer lights, I am getting the ADC out of range shutdown error in mainsail. I have disconnected the SSR and bed heater from the MCU. I cannot find any Information on How to test the bed heater with a Multimeter, I have continuity between the wires that power the bed, but the "red" wires that connect the pad to the MCU do Not have continuity, Is my heat pad ruined?
You don't want to use solder on mains power but solder is how ever mains device in your house is connected. TV power cable in to socket on TV that is SOLDERED to the main board. Shit now adays even toaster are soldered power cords as most of them and a circuit board in them. That being said I would feel safer with something that mechanically would not come apart under any loads so solder it because 110V mains charged base plate sounds like no fun.
Looking to do this with my Ender 5 plus. Now, what kinda wattag should o be looking for? Dont need overkill, but average to good. Similar to original would be ok.
Good work , but not sure about sticking that self adhesive magnet to the top of a high end flat surface , that Sticker magnet will not be flat adhesive is laid uneven
You need room for the screws/fuse etc. So either a stock off the shelf heater thats undersized or a custom, higher cost heater with cutouts. Thick aluminum is very good at heat transfee so the top is pretty uniform
Thank you very much for your fast reply! Last question: you are putting the magnet foil on both bed and spring steel sheet. Is only on the bed not enough?
Should I use 2 thermal fuses, one for each of the AC wires? I am interested in doing that because I am unsure which of the wires coming out the wall is the live and which is the neutral (as there is no standardised way where I live in Europe). If the answer is yes, should I use 2 ssrs too? One for each cable, like with the fuses? Im thinking: wall > ssr 1 > fuse 1 > 1st wire of silicon pad, then the 2nd wire of silicone pad > fuse 2 > ssr 2 > back to wall I would be driving the first ssr with pmw signal from motherboard, however Im unsure how the 2nd ssr would be driven. A silly question, probably, but I thought whats the harm in asking...
Is a thermal fuse necessary for DC heated beds? I am using a robust MOSFET to control current for a 200W 12V Keenovo heater on an old printer. I am having a hard time finding any information about thermal fuses other than in the case of mains powered installations.
SSR Failure modes are.... 'Fail Open... Output can no longer be switched closed. Fail Closed.. Output can no longer be switched open. Catches Fire.. Device continues to operate but gets too hot and ignites. Will be followed by either mode 1 or mode 2 if there is anything left once you put the fire out. Which particular mode will occur is application and device specific and is a matter of probability. Operating the device outside it's specified ratings will significantly increase the probability of failure, however, operating it well within those limits will not prevent it's eventual failure. Generally fail open or fail closed is hard to be sure about. The best you can state is the device is more likely to fail one way or the other under normal or extraordinary load conditions. But both modes will have a finite probability of occurring for that particular device. As such, when designing critical systems where you need to be sure the output enters a certain state when a failure occurs, additional circuits and methods are required.'
Do you happen to have the 3d cad file for this plate? Or know where i can download it? Specifically, I'd like the 350 x 350 plate cad file. Thanks for your content, I'll be watching more!
Perhaps you could arrange a demonstration showing the difference in heating times between the AC heated thick aluminum bed and a DC heated thick aluminum bed?
If the heaters are the same wattage then sure, they will heat up the same. But Watts = Volts x Amps. So if you have a 500 Watt heater running off of 120V then it only needs power from the wall to supply about 4 amps. If you have a 500 Watt heater running off of 24V then it needs a PSU than can supply 20 Amps. High Amperage PSUs get expensive pretty quick.
5 mm should be enough for 250x250 mm. And I don't like the PEI-sheets. Better go with coated spring steel plates. They usually have two sides and a much better surface and the surface doesn't come off so easily like with the PEI sheet. Also the print usually sticks much much better and more homogeneous to the coated sheet.
Did a similar build using 1/4 inch Cast Aluminum Tooling Plate...Guarantied flatness.... I routed the square edges to quarter round edges. Looks very nice. Scuffed the entire surface using some quick change sanding pads. The mistake I made was rounding the edges. That changed the overall tension on the top side. And after a few cycles of heating and cooling it warped up over the heating pad. Now have a higher middle by .0035. Leave the edges square.
Because with excessive heat the solder may melt/soften and you will have a mains powered bare wire just dangling around. Crimps are supposed to hold onto the wire mechanically, and are much less prone to heat related failures (to a certain extent, of course).
@@havenview assets.nexperia.com/documents/application-note/AN11243.pdf "Typically the consequence of [Electrical Overstress] is the short circuiting of at least 2 of the 3 MOSFET terminals (gate, drain, source)."
@@Graham_Wideman a MOSFET short melts the die and opens the circuit. You've discovered the fault but not considered the consequences - I suppose though you can find any answer you want on the internet !
Verify with a meter. Mine shows open due to the coating on the aluminum extrusion. The inside aluminum that is bolted together with the blind joints have continuity, but if I place a probe on the black part of the extrusion there is no continuity. I would advise to place a ground directly on the plate for redundancy if nothing else.
How does the fuse move from the edge to the middle? Woosh.... :) Also I was thinking about adding two fuses. One on the mat and one on the bed. But that's probably overkill.
RTV is removable - start by mechanically removing most of it and then one can use a 'silicone remover' (available from the hardware store) to clean up the rest. The heat mat adhesive will usually come off with acetone.
My friend took one of the build plates from one of my Ender 3 printers to work and faced the surface on the milling machine, it was super level with a mirror tile build surface, for a while, but then I noticed the odd very small inconsistency here and there, I am guessing this is down to thermal expansion. Do you think it worthwhile to have the cast plate faced or would the difference be unnoticeable?
@@CanuckCreator thanks for the info. My bed is warped even with a glass bed...I want to get the whambam with PEX build plate but I'm not sure the best way to go about doing it without a level bed surface. I do have an EZABL installed but I'm still afraid to purchase anything without knowing the best way...any thoughts? TIA
@@jrodbrown58 I have a CR-10S, and the best two upgrades have been the BLtouch and the AC silicon heater. I then also added a magnetic flexible plate, that is too a nice to have, and even gave me an unexpected benefit of reducing ringing as the spring steel is lighter than glass (and also not to risk my life with metal clips directly clamping on the silicon heater!). Anyway the bed still warps like crazy, but the mesh leveling keeps everything under control, no problem whatsoever even with the first layer.
I don’t know If I’m in quite the right context here. But when sourcing a build plate for a large format printer, has cast Iron ever been seriously considered as potential material from which to have one made?
This is great info and am following it for the most part. I'm curious as to why you would take a known flat surface like a cast aluminum tooling plate and add a sheet magnet to it? I can't imagine that the magnet's production quality is anywhere the same as the plate when it comes to consistency across the surface. Do you have a source for sheet magnets that are as consistently flat as cast aluminum tooling plate?
I have not used an AC-powered heater bed. Is there a significant difference in time to temp over say a 24V DC heating bed when heating to ABS / Polycarbonate temps, i.e. 100 to 130 C?
It is generally quicker, but the main reason is that it's simply a smarter design: you need a smaller PSU (cheaper and less noisy) and probably better power consumption, while requiring smaller wiring and being faster too!
I moved mine from 24v to 240v and ABS heat up time is like 3mins instead of 7-8mins for my 300x300x6mm plate. For PLA low temps it's not that big of a deal but for ASA/ABS/PETG I think it's a must have.
I'm using an energetic double sided PEI flex sheet for my flashforge creator pro from AliExpress and it's been great based on that I've order a 350 on to use on my Voron 2.4 because the one that came with the formbot kit quite frankly looks crappy
good video nero. personally i would add the following steps: be sure to get multiple thermal fuses ffrom same vendor / batch. so then you can double check for yourself and test one or two of them by blowing it at the rated temperature. i think that is important step to give yourself a confidence in the product. 2nd to that i would be attaching a 2nd thermal fuse in series, on to the bed itself. that way if the 1st thermal fuse were to fail for any reason... there is a backup one that will then blow instead. now for ssr stuck on issue. the bed SSR (and for any ssrs for that matter). should be in series with an active closed safety relay. and that safety relay should be wired up to an mcu. so if the ssr is stuck on then there will be a way to shut it off. perhaps klipper can be smart enough to detect this situation. simply be monitoring the bed temp in response to commands. anyhow the point is to have another alternative safety cut out. which operates independantly be an entirely different mechanism. you want it so that if power is cut to the safety relay (or the mcu driving it)... then it de energises as its failure mode now the shorting to ground. you do want a regular fuse. but also an rcd (or whatever you call them)... specifically for all of the printer circuits too is not a bad idea either. so that if it does trip you dont have to go all the way to your control box. and just an extra rcd breaker for that printer is just extra layer of safety i dont think you can be too safe so its always good to think of extra independent ways to provide an alternate safety cut out mechanism. i would also suggest installing multiple smoke alarms above the printers. at least from 2 different brands. and actually hack at least one of the smoke alarms to provide an alarm signal to the safety cut out circuits for the whole printer. however you also need to make sure the smoke alarm wont be triggered accidentally by abs fumes etc. safety circuits are not meant to be a substitute for fundamentally safe design to begin with. but having a safe design is not an excuse for forgoing safety cut outs either! both should be implemented especially in circumstances where you want to leave equipment running unattested finally.... the ultimate safety 'luxury' as it were is to have a shed or outhouse. that is not in the main building. but is instead erected a safe distance away from all other buildings and structures. that might be a lot more or less convenient for some people. but if you have the option to do so.... then by all means it is probably the best and most worthwhile single safety upgrade out of anything else hopefully those tips might be helpful to somebody else out there. but regardless i do think you made an excellent video here nero3dp for showing regular people the very best practices and methods for assembling a high quality printer bed. really thank you for taking the trouble to explain things so well and make easy for others to follow
ironically the easiest way to make the SSR redundant is to add another SSR :D daisy chain them and you're golden, risk is significantly lowered. To be honest however, I think that the thermal fuse is good enough considering the plate is hard mounted to aluminium extrusions and not really a fire hazard. The keenovo heater can run flat out at it's rated power like an enclosure heater until the fuse pops. Placing two fuses in series does make sense like you mention and I agree - testing that they work is very important. Have you installed an RCD in your printer? What's the easiest way to achieve this? - A recommendation could be made to the voron dev team?
@@justindelpero there are drawbacks of doing it that way. for a start decent SSRs cost money (up to $50 even). which is pretty expensive. and 2nd to that, if your control board does not detect a failed stuck on SSR.... then it keeps going for some weeks. Then you could end up with the redundant SSR then failing later on in the same fashion. When you already have 1 SSR to PID control the bed temp. Then you don't need a 2nd SSR for any rational reason. You should instead use a regular on/off relay in series. As I have already mentioned above here. Since those are much more reliable, can be active-on (safer way if signal is cut). And if they fail they usually fail open circuit. The cost? about $2 vs $50 for a good one. And safer too. But you would have extra SSRs for multiple individual other heating circuits. For example PTC heaters, filament driers, etc. In each case you should series a regular relay with the SSR (and have that relay being controlled by an mcu that monitors the SSR and can detect if it has failed).
![KAYTRANADA - Witchy (feat. Childish Gambino) [Official Video]](http://i.ytimg.com/vi/jGK3YVmGZ3Y/mqdefault.jpg)
Yes! Keep making these 10 minute detailed build guides. So helpful when understanding what all is needed and how the process of each build step should go. Great job.
Yes 100%. I enjoy the live streams, but they can be very hard to find specific information. If I am looking for how to make the build plate, or assemble a specific part it sucks scrubbing through 2 or 3 hours to find info. These concise videos are great.
When you attach the ground wire it’s a good idea to put a shake proof washer between the ring and the plate. The teeth on the washer bite through the thin oxide layer on the aluminium to make a better contact.
Good work Nero !! very well made video. keep them coming
Dude, eeeevery f***n detail. Even grounding the plate, which 90% miss out on. You got every single detail! Great video & content!
Nope, he missed protecting the wires from the abrading on the edge of the plate. strain relief is not a substitute.
@@joshua43214 I dunno. The plate is for a Voron, where it won't be moving at all.
If the plate was moving along y or z, then yes, then protection is mandatory. But in a Voron, the cables will not see any movement what-so-ever.
@@docpayce1 The bed of the Voron 1.8 does move on the Z axis, the static bed is on the 2.4
That will be covered during installation
@@vinnycordeiro Aaah, I See. Ok, ty for clearing that up!
I previously applied a keenovo and a thermal fuse and thought I "knew all this" - I actually learned quite a bit from this - THANK YOU!
Minor correction: SSRs fail 'closed' not 'open' (IE. the switch is closed and conducting). Excellent video - thanks!!
Flubbed a line. Good catch
Rumour correction: SSR's CAN fail closed. They can also fail open as well.
@@Fuckoff-1 yep just it's more common for them to fail closed
Did anyone else think they heard, “In The Air Tonight”? When this video first started? Great video!
Nice video, thank you. I'd like to mention (albeit 3 years late,) that the thermal expansion coefficient of aluminum is unaffected by its manufacturing method. Aluminum has around a 24x10^-10 TE coefficient. So the claim that it doesn't expand is not true. Other than that though, great video. Ty
Now that (cast, milled aluminium bed) information is pure gold. Finding quality components is a nightmare.
Small correction in terminology: In electronics, when something "fails open" it means it fails open circuit. I.E non-conducting. The two fail states are described as failing open and failing short. Failing open is the safe one. Your use of "fail open" is the one applied to water valves etc, in that when they fail open, they fail with the valve open.
Hey fellow Canadian! Because you are making an electrical connection to aluminum (the ground connection), best practice is to use electrical joint compound between the crimp and the bed to prevent possible future corrosion. Aluminum is highly susceptible to oxidization, especially when in contact with dissimilar metals. We call it Penetrox, but there are other brands available. To be clear, it is not dielectric grease. Love your videos, by the way. I credit a lot of my success with my current build to you, haha
Oh that's a good point. I have some no alox stuff I use when I have aluminum wires landed in an electrical panel, I should put a little on my printer bed ground!
Just for clarity, are you sugesting to apply some compond inside the crimp? and would this apply for all crimps and ferrules that would be used with the copper wire inside a printer build? you suggestion has raised some alarm bells in my head....
@@richk6216 no, those pins are plated copper pins. They don't need anything. This is just for the ring terminal to the aluminum plate.
@@hondaguy9153 ah that makes sense, thanks for the clarification 👍
One thing to mention about connecting the fuse: Solder joints work perfectly well at mains voltage, and even voltages above that. However, they are low temperature welds, and heat cycling at the 100°C that some filaments require would cause problems long term. I disagree with your usage of automotive crimp connectors, as manufacturers frequently don't certify them above 24V DC, and even lower voltages AC. I'd suggest instead using what electricians use: Mains insulated screw connectors, or Wago-style snap connectors, along with ferrules. They are intended for use in house wiring, and thus support both the voltage and currents you need. They also have the added benefit of being simple to disconnect if needed.
If you were working in a factory, waffle iron and coffee maker manufacturers frequently use solid core wire (as well as thermal insulation you wouldn't need for this application), and spot-weld it to their in-line fuses.
It would be good to see a thermal camera view of the bed when in operation, especially at higher operating temperatures to emphasize any gradient. I would expect that a major effect in warping would be differential heating and thus expansion of the middle of the bed compared to the periphery. The middle would expand but yet be constrained by a less-expanding outer ring, inducing a bow up or down perhaps. For this reason, I think it would make sense to insulate the exposed peripheral inch or so of underside, so that at least that outer area loses less heat and would come up to a temperature more similar to the middle. If in practice a bow is not seen, then it would still be informative to see the heat map to learn what amount of temperature drop-off at the edges failed to produce a bow. Of course, these considerations are not particular to the bed discussed here, but as long as we're getting all sciencey on this one, it would be great to see how these variables play out!
There a photo of my bed plate (8mm cast tooling plate, 300x300mm) here: 2.bp.blogspot.com/-PASdLoJVJes/WZO-mOZF3-I/AAAAAAAAGpY/xY3oYLw1KM4gSspIzeLgnmpytTdFPzeIwCPcBGAYYCw/s1600/UMMD%2B105C%2BFLIR.PNG
The heater is 300x300 mm.
I would not recommend using a plate that bigger than the heater (like this video) because the edges will be cooler than the center which will lead to warping when heated.
@@MarkRehorst Thanks for that interesting IR image, quite informative!
@@MarkRehorst neat
For a cast aluminum plate, that's right: Any warping would probably be a consequence of uneven heating. For an extruded or otherwise formed plate all bets are off - those can have residual stresses that cause them to warp even when uniformly heated.
Was looking for exactly that. Thanks for covering this topic!
One thing you *REALLY* *NEED* is to protect those wires from the edge of the plate.
Use properly rated heatshrink you get from a reputable supplier (the local big box store is fine). You want the stuff that is used in mains wiring. It will be expensive, and really thick. Do not not imported stuff unless you know for a fact the certification has not been forged (all the inexpensive stuff on Ebay and Amazon are probably forged certificates).
A single layer of Kapton tape should be under on the bed that comes up over the edge under wires is secondary protect.
That sort of thing along with mounting the bed will be covered during the install.
What's the reason you wouldn't recommend soldering the mains voltage wires?
Does the silicone you use to mount the thermal fuse insulate it from the heating mat in any meaningful way?
It's not ideal, but it'll still reach a steady state not much lower than the heater. At least with some insulation if the heater overshoots on heat up by a bit it won't trip the fuse unless that overshoot persists a decent amount of time.
I love the Voron plate! Is this the first Voron-themed plate you've used? Also, is there any particular reason the PEI sheet isn't yellow? Is this a special high-temp thing for Toasty Boi?
The black pei and flexpate is from Fermio.xyz. black cus it looks cool
Oh boy I didn't know I had such an amazing store as Fermio labs so close here in the EU. Absolute chads. Thank you again Nero for sharing all this awesome knowledge. Makes too much sense that such a thicc plate is super stable thermal wise!
Me neither! I was already happy to find out that Filafarm was selling thick plates and they are also based in Germany. Great to have both options available.
Take from a person that did this 5 years ago with a MIC6 Plate.... I highly recommend mounting it on springs so it can expand/retract and still maintain Z = 0.. even with tight PID heating, you'll get artifacts as that large plate expands and retracts with heating/cooling. With BLTouch and mesh bed leveling becoming a thing, it got rid of the need to have a high tolerance flat print bed these days
I run mine mounted on both my v2s with a basic 3 point fixed mount. And even after years of use im still able to get by without a mesh as the surface is still flat enough
@@CanuckCreator thats not what i am saying. Fixed mount will cause what looks like z wobble artifacts because your fixed plate is expanding and contracting. It is made worse because of how thick your plate is. Springs allow the plate to expand downwards and maintain z=0. The mention of mesh leveling is that flat tolerance of MIC6 is not even needed anymore and hasnt been for years. Hence why no one bothers with cast plate anymore.
@@ShadowRam242 To be clear, if the build plate expands downwards, should we infer that the mounting consists of flat-head bolts countersunk into the surface of the build plate, with springs pushing up from the bottom? So your confidence in the build plate fixed Z height is because the top surface is "held down" at a fixed Z height by the bolts, right? This assumes (a) that the bottom of the bolts' countersunk heads are close enough to the surface of the plate that the height of aluminum above them is negligible, and (b) that the bolts themselves do not expand and contract with heat. Both of these may be valid assumptions, but I just wanted to see it spelled out.
@@ShadowRam242 It's not that it hasn't been needed for years rather it was more expensive to get plate and have it machined and chinese 3dp companies did not want to eat that cost. I did the same thing with the CR-10 in 2017 and the Wanhao D6 came with a cast plate. There are people that were building cast plate beds prior to 2014 and they used 3 point leveling.
Like some other comments, I think you are adding insulation on your runaway fuse. Probably should test one.
Does anyone ever apply magnetic sheets or any of these adhesive items like window tint or automotive decals where they use windex or a soap solution to lube the sheet to allow for moving it around and removing bubbles and then when it all drys it is all flat?
So, I did this install about 2 years ago. Last night I rewatched the video - after noticing my bed was bowing and i coudl press it inwards around the center (kind of like my own stomach) - turns out the adhesive was failing, and the RTV held the edges quite solidly. THANK YOU. I don't know how close to a house fire I came (if at all) but I'm incredibly grateful for the RTV tip. As I now await my new heater.
0:43 - do you mean Blanchard ground? I'm gonna assume you meant Blanchard. :o)
Perfect and complete tutorial (including what not to do 😁). Thank you. 👍👍😎👍👍
That was exactly the video I needed as I have a similar thick precision print bed kit from Filafarm (based in Germany) sitting here waiting for installation. Various print projects keep me from finally starting with the installation and I'm also no electrician so I was slowly gathering all the knowledge needed to do this safely. Your video nicely summed up all the bits and pieces I found across the web including some tips I didn't see elsewhere (like the extra heat resistant silicone around the heater mat).
Btw. my heat protection fuse is not a cased variant like yours but instead looks more like a basic transistor. Are there advantages to the one you use?
Good video - maybe just test that the matt actually works before you stick it down and add silicone sealant :P
Great Job ! Much Thanks, loved the Format !
Keep up the good work.
I was interested if the gasket glue is could also release a kin to the 3M adhesive which is holding the fuse. So a possible overkill could I run 2 fuses in series. One attached to aluminum and screwed that other stuck via gasket adhesive to the heater mat. Or is that really overkill.
Couldnt find tooling plates, so I do mines with 3/4in (20mm) plates. Nice thing is I can drill and insert the heater core in the plate so I can add more if needed.
Thermal fuse is really important, I had a relay sticking and the bed when up to 280c the whole night. Came back to look at a pool of petg and 75$ of wasted magnets.
nit: test the wiring and components are working before glue it down.
That weight won’t do anything. Keenovo say to apply 2kg/cm3. That is 1800kg!! For a 300x300 bed. A paint silicon roller will do the work for you.
I wondered about that too!
Great video
Do any of your printers have that death stink from the 3M adhesive? Mine didn't for months but has developed it. Woof.
something to maybe consider.... if your thermal fuse falls off as heat rises and then it loses the protection it was designed for..... There is usually nothing under where you mounted it to catch it... Maybe best to use Both a bolt on one And one as you have? being mindful that many follow you and print when not home and overnight? cheap insurance? NOT being the fire chief just a observation... Rock on man your doing a great job!
Doesn’t the Silicon adhesive act as a heatbreak resulting in a higher than rated temperatur for the fuse to break?
I find the discussion about "cast" aluminium plates very funny. I worked in a aluminium factory as a young engineer. Every aluminum plate starts as a cast block of alu. That is then rolled into flat shape. It is then heated up to 460 - 560 °C to homogenize the crystal structure in the metal. So actually if you buy a rolled piece of aluminum that was homogenized it is more stable for bending when heating up or cooling down as a not heat treated piece of really casted aluminum.
Many printer beds are made by extrusion, which you may know better than me that it induces a lot of stress in the metal crystalline structure.
@@vinnycordeiro I don't work in that area for over 25 years now, but it would not make sense to me to use a complicated process like extrusion for a simple flat slab of aluminum. Especially as cutting a generally available slab of aluminium is much easier with minimal waste. Extrusion is a complicated process that requires complex machineries and therefore commonly used for profiles that cannot be produces in another simple way. To me that hole "casted bed" just sounds like a new buzzword to rip off people. But that is my opinion.
@@Empusas1Goto Alibaba and look at how the factories are making their beds and you will see why there are so many problems with cheap rolled aluminum beds.
@@Deneteus Lot to unpack here.
First the properties of aluminum depend mainly on the alloy used. There are many alloys used today for different purpose. I doubt that you can find a 99,9% aluminum plate. For rolled plates, foils etc often used alloys are AlCuMg, AlCuSiMn, AlMgSi, AlZnMg and AlZnMgCu. The same type of alloys is used for aluminium that is rolled, extruded or cold forged. Every time you mechanically change the shape of a metal object you get tensions in the object and distort the natural crystalline metal structure. To remove those tensions there is the process of homogenizing that I described before. In additional those alloys can be hardened by heating them up to 120 -175°C for 1-2 days and let them cool down in a controlled curve. You may look up duralumin for more.
For castings different alloys are used like AlSiMg, AlSiCu, AlMg, AlMgSi, AlCuTi, AlCuTiMg. Those are not suitable for any extrusion or other mechanical reshaping as they have a natural hardness that would let the parts break or crack. Those either casted into the final shape or a blocks of aluminum that are cut into slabs and/or milled into shape.
So the alloy defines how the block of aluminum can the processed into the final shape.
It is true that there are companies that sell slabs of casted aluminum for special purpose like the company "Gleich" in Germany for example. They also heat treat the aluminum block to homogenize them before the cut them into pieces. There is video about the process shown here: ruclips.net/video/HBvVleIO75A/видео.html
different
@@Empusas1 I like how you went on a tangent when i never said anything about alloys or 100% aluminum plate. I said the word cheap. I am already aware of everything you just said. That doesn't change the fact they are cheap and typically attempt to return back to their original shape over time when heated.
Great video! I'm currently building a V-Minion and I just did the bed based on this tutorial. I'm just missing the silicone gasket seal. Any tips of what to get in Germany?
The problem is a SSR failing *close*, not open. Other than that, I just had a mind-blown moment on how to break the seal on the RTV. 🤯
The high temp rtv comes in black. Is there a difference between red and black high temp rtv?
Very nice video. No need to insist on cast alluminum tho.your printers frame tolerances are way higher then difference in warping between cast and rolled alluminum plate.i bet if you could scan frame and compare diagonalls othey would be off by 2 mm for shure. Also you glue on top magnetic sticker and put up spring steel sheet. So ...
Problem with rolled alluminium is that it warps after heating many times.
What is the difference in heatingtime at 12v, 24v, 48v, 110v & 220v silicon heater?
I want a silicon heated bed but i am a bit hasitant to put 22v on my printerbed.
I was thinking about a 48v silicon heater.
So can anyone tell me what the heatingtimes are of theese heaters?
I believe my SSR failed, the light no longer lights, I am getting the ADC out of range shutdown error in mainsail. I have disconnected the SSR and bed heater from the MCU. I cannot find any Information on How to test the bed heater with a Multimeter, I have continuity between the wires that power the bed, but the "red" wires that connect the pad to the MCU do Not have continuity, Is my heat pad ruined?
You don't want to use solder on mains power but solder is how ever mains device in your house is connected. TV power cable in to socket on TV that is SOLDERED to the main board. Shit now adays even toaster are soldered power cords as most of them and a circuit board in them. That being said I would feel safer with something that mechanically would not come apart under any loads so solder it because 110V mains charged base plate sounds like no fun.
@6:07 you say your V2.6 printer are you saying there are upgrades inbound?
That was his Voron 2.4 serial number. V.026. Yeah it did sound like he said V.6
@@danny8739 I'm getting all excited when I hear upgrades lately, lol.
Looking to do this with my Ender 5 plus.
Now, what kinda wattag should o be looking for? Dont need overkill, but average to good. Similar to original would be ok.
Hey .. I'm making my own bed but i want able to get MIC 6 OR ATP 5...but can I use 7075 sheet ??
Ha! My Keenovo turned up this morning for my Voron 1.8 build.
Mine must have been on the same slow boat as yours.
@@fwiffo To be fair, two weeks door to door.
@@Kosh42EFG Mine was on a much slower boat then...
Just order one that fits, you have uneven temperatures.
🤔 I think i can make LARGE FORMAT HEATPRESS for this 😁
Good work , but not sure about sticking that self adhesive magnet to the top of a high end flat surface , that Sticker magnet will not be flat adhesive is laid uneven
What kind of mat is that you are able to cut on? That green one?
Sir which aluminum grade is best for custom 3d printer bed
The seller is asking about grade which you need
At 4:09 maybe a tip would be to align the non sticky end first since you can align a longer part before the glue sticks.
Why is the heater pad smaller than the bed itself? How is the thermal uniformity at the top side of the bed?
You need room for the screws/fuse etc. So either a stock off the shelf heater thats undersized or a custom, higher cost heater with cutouts.
Thick aluminum is very good at heat transfee so the top is pretty uniform
Thank you very much for your fast reply!
Last question: you are putting the magnet foil on both bed and spring steel sheet. Is only on the bed not enough?
@@simontillema5599 its not magnetic foil, but a black PEI sheet.
Thanks for sharing your experience with all of us 👍😀
Great timing. My V0 bed heater finally, *finally* came in today.
This stuff costs a fortune to source in my country 😔
Would you install a thermal fuse to an MK52 style bed?
Should I use 2 thermal fuses, one for each of the AC wires? I am interested in doing that because I am unsure which of the wires coming out the wall is the live and which is the neutral (as there is no standardised way where I live in Europe). If the answer is yes, should I use 2 ssrs too? One for each cable, like with the fuses?
Im thinking:
wall > ssr 1 > fuse 1 > 1st wire of silicon pad, then
the 2nd wire of silicone pad > fuse 2 > ssr 2 > back to wall
I would be driving the first ssr with pmw signal from motherboard, however Im unsure how the 2nd ssr would be driven.
A silly question, probably, but I thought whats the harm in asking...
Is a thermal fuse necessary for DC heated beds? I am using a robust MOSFET to control current for a 200W 12V Keenovo heater on an old printer. I am having a hard time finding any information about thermal fuses other than in the case of mains powered installations.
SSR Failure modes are....
'Fail Open... Output can no longer be switched closed.
Fail Closed.. Output can no longer be switched open.
Catches Fire.. Device continues to operate but gets too hot and ignites. Will be followed by either mode 1 or mode 2 if there is anything left once you put the fire out.
Which particular mode will occur is application and device specific and is a matter of probability. Operating the device outside it's specified ratings will significantly increase the probability of failure, however, operating it well within those limits will not prevent it's eventual failure.
Generally fail open or fail closed is hard to be sure about. The best you can state is the device is more likely to fail one way or the other under normal or extraordinary load conditions. But both modes will have a finite probability of occurring for that particular device.
As such, when designing critical systems where you need to be sure the output enters a certain state when a failure occurs, additional circuits and methods are required.'
Your channel is so bad Ass dude!
Do you happen to have the 3d cad file for this plate? Or know where i can download it? Specifically, I'd like the 350 x 350 plate cad file.
Thanks for your content, I'll be watching more!
The .DXF is on the voron github
I did this but I am concerned because Gardner-Bender heat-shrink Butt Splice connectors say they are only rated for 105°C on the back of the package.
Perhaps you could arrange a demonstration showing the difference in heating times between the AC heated thick aluminum bed and a DC heated thick aluminum bed?
If the heaters have same power there is no difference.
If the heaters are the same wattage then sure, they will heat up the same.
But Watts = Volts x Amps.
So if you have a 500 Watt heater running off of 120V then it only needs power from the wall to supply about 4 amps.
If you have a 500 Watt heater running off of 24V then it needs a PSU than can supply 20 Amps.
High Amperage PSUs get expensive pretty quick.
What aluminum alloy is it? 6061?
Hey @Nero 3D what r the connections from fuse 2 cable called? and they r able to go 120-130 celsius?
Thanks Ive been meaning to get my red RTV on.
5 mm should be enough for 250x250 mm. And I don't like the PEI-sheets. Better go with coated spring steel plates. They usually have two sides and a much better surface and the surface doesn't come off so easily like with the PEI sheet. Also the print usually sticks much much better and more homogeneous to the coated sheet.
Did a similar build using 1/4 inch Cast Aluminum Tooling Plate...Guarantied flatness....
I routed the square edges to quarter round edges. Looks very nice.
Scuffed the entire surface using some quick change sanding pads.
The mistake I made was rounding the edges. That changed the overall tension on the top side. And after a few cycles of heating and cooling it warped up over the heating pad. Now have a higher middle by .0035.
Leave the edges square.
Hi thanks for share, where could I buy the aluminum plate? Where did you get it?
Best regards
why not soldering thermal fuse?
Because with excessive heat the solder may melt/soften and you will have a mains powered bare wire just dangling around. Crimps are supposed to hold onto the wire mechanically, and are much less prone to heat related failures (to a certain extent, of course).
Is this heater capable of reaching higher temperatures like 200 or 300 degree Celsius?
Heater yes but the adhesive will fail well before that. This is not meant to be a high temperature heater
Is the thermal fuse also required with MOSFET-controlled DC-beds?
Yes, it's a safety measure related to the temperature itself, not on how the bed is fed energy.
@@vinnycordeiro Its a safety measure related to the tendancy for SSRs to "fail on" - MOSFETs don't tend to do that
@@havenview assets.nexperia.com/documents/application-note/AN11243.pdf "Typically the consequence of [Electrical Overstress] is the short circuiting of at least 2 of the 3 MOSFET terminals (gate, drain, source)."
@@Graham_Wideman a MOSFET short melts the die and opens the circuit.
You've discovered the fault but not considered the consequences - I suppose though you can find any answer you want on the internet !
Can the the plate be connected to ground via the aluminium extrusions it's mounted to?
Yes
Verify with a meter. Mine shows open due to the coating on the aluminum extrusion. The inside aluminum that is bolted together with the blind joints have continuity, but if I place a probe on the black part of the extrusion there is no continuity. I would advise to place a ground directly on the plate for redundancy if nothing else.
How does the fuse move from the edge to the middle? Woosh.... :) Also I was thinking about adding two fuses. One on the mat and one on the bed. But that's probably overkill.
Is red RTV removable? If I were to swap heaters down the line, would I need to buy a new build plate?
RTV is removable - start by mechanically removing most of it and then one can use a 'silicone remover' (available from the hardware store) to clean up the rest. The heat mat adhesive will usually come off with acetone.
@@CDN_Torsten Thank you very much!
Great info Thank You 👍
It seems there is no problem replacing the fuses if they break? I take it you just removed the misplaced fuse after it dried?
Good to know. Heat from silicon heatbed broke my 4 mm glass at a temperature of 120 C lol
So I can stick the fuse on the heated bed instead of drilling the plate ??
I think it’s Blanchard ground not blanch(e). But the video is super useful
My friend took one of the build plates from one of my Ender 3 printers to work and faced the surface on the milling machine, it was super level with a mirror tile build surface, for a while, but then I noticed the odd very small inconsistency here and there, I am guessing this is down to thermal expansion.
Do you think it worthwhile to have the cast plate faced or would the difference be unnoticeable?
Your real name is on the heatgun in case you care
It's only his daytime name. At night he becomes Nero 3dp!
Can this be done to the ender 3? Or is there any aftermarket ones for the ender 3?
The weight of this style bed. And mains voltage wires. Means this style of bed is best user when it can be fixed in place or z travel only imo
@@CanuckCreator thanks for the info. My bed is warped even with a glass bed...I want to get the whambam with PEX build plate but I'm not sure the best way to go about doing it without a level bed surface. I do have an EZABL installed but I'm still afraid to purchase anything without knowing the best way...any thoughts? TIA
@@jrodbrown58 personally im a fan of spring steel flex magnetic plates and a cheap inductive probe
@@jrodbrown58 I have a CR-10S, and the best two upgrades have been the BLtouch and the AC silicon heater. I then also added a magnetic flexible plate, that is too a nice to have, and even gave me an unexpected benefit of reducing ringing as the spring steel is lighter than glass (and also not to risk my life with metal clips directly clamping on the silicon heater!). Anyway the bed still warps like crazy, but the mesh leveling keeps everything under control, no problem whatsoever even with the first layer.
@@jrodbrown58 Are you sure your bed is warped? Maybe it is your gantry...
Thanks for the video and the extra time spent peeling off that painter's tape. So satisfying!
Soooo what do you do for your mounting holes after you cover them up with the magnet
Cut a hole in the magnet
@@CanuckCreator Well obviously! 🤪 But what’s the best way without it looking like a 5th grader did it? Can I drill the magnet and get a nice finish?
Would a cast aluminum bronze alloy work for the bed?
I don’t know If I’m in quite the right context here. But when sourcing a build plate for a large format printer, has cast Iron ever been seriously considered as potential material from which to have one made?
Usually not considered to size/weight/cost considerations for a flat enough peice
nice
should you insulate the bed for better thermal absorbtion?
I did learn something new. That thermal fuse is a great idea. Thank you!
This is a great one! I'll be linking this one to folks for a long time, I think. Thanks!
Great safty points. I'll be making a cast 240v heated bed soon so I'll be adding a thermal fuse and ground strap!
This is great info and am following it for the most part. I'm curious as to why you would take a known flat surface like a cast aluminum tooling plate and add a sheet magnet to it? I can't imagine that the magnet's production quality is anywhere the same as the plate when it comes to consistency across the surface. Do you have a source for sheet magnets that are as consistently flat as cast aluminum tooling plate?
Ive used both generic cheap magnets from energetic on aliexpress to graviflex magnets and neither have impacted flatness to the point its an issue
will there be a thermal camera pictures?
I have not used an AC-powered heater bed. Is there a significant difference in time to temp over say a 24V DC heating bed when heating to ABS / Polycarbonate temps, i.e. 100 to 130 C?
It is generally quicker, but the main reason is that it's simply a smarter design: you need a smaller PSU (cheaper and less noisy) and probably better power consumption, while requiring smaller wiring and being faster too!
I moved mine from 24v to 240v and ABS heat up time is like 3mins instead of 7-8mins for my 300x300x6mm plate. For PLA low temps it's not that big of a deal but for ASA/ABS/PETG I think it's a must have.
Are energetic pei magnetic flex sheets good for high temp, I know you used them on your V2.4 but do the magnets hold while printing ABS
Ive had zero issues with my energetic plates so far
I'm using an energetic double sided PEI flex sheet for my flashforge creator pro from AliExpress and it's been great based on that I've order a 350 on to use on my Voron 2.4 because the one that came with the formbot kit quite frankly looks crappy
good video nero. personally i would add the following steps: be sure to get multiple thermal fuses ffrom same vendor / batch. so then you can double check for yourself and test one or two of them by blowing it at the rated temperature. i think that is important step to give yourself a confidence in the product. 2nd to that i would be attaching a 2nd thermal fuse in series, on to the bed itself. that way if the 1st thermal fuse were to fail for any reason... there is a backup one that will then blow instead.
now for ssr stuck on issue. the bed SSR (and for any ssrs for that matter). should be in series with an active closed safety relay. and that safety relay should be wired up to an mcu. so if the ssr is stuck on then there will be a way to shut it off. perhaps klipper can be smart enough to detect this situation. simply be monitoring the bed temp in response to commands. anyhow the point is to have another alternative safety cut out. which operates independantly be an entirely different mechanism. you want it so that if power is cut to the safety relay (or the mcu driving it)... then it de energises as its failure mode
now the shorting to ground. you do want a regular fuse. but also an rcd (or whatever you call them)... specifically for all of the printer circuits too is not a bad idea either. so that if it does trip you dont have to go all the way to your control box. and just an extra rcd breaker for that printer is just extra layer of safety
i dont think you can be too safe so its always good to think of extra independent ways to provide an alternate safety cut out mechanism. i would also suggest installing multiple smoke alarms above the printers. at least from 2 different brands. and actually hack at least one of the smoke alarms to provide an alarm signal to the safety cut out circuits for the whole printer. however you also need to make sure the smoke alarm wont be triggered accidentally by abs fumes etc.
safety circuits are not meant to be a substitute for fundamentally safe design to begin with. but having a safe design is not an excuse for forgoing safety cut outs either! both should be implemented especially in circumstances where you want to leave equipment running unattested
finally.... the ultimate safety 'luxury' as it were is to have a shed or outhouse. that is not in the main building. but is instead erected a safe distance away from all other buildings and structures. that might be a lot more or less convenient for some people. but if you have the option to do so.... then by all means it is probably the best and most worthwhile single safety upgrade out of anything else
hopefully those tips might be helpful to somebody else out there. but regardless i do think you made an excellent video here nero3dp for showing regular people the very best practices and methods for assembling a high quality printer bed. really thank you for taking the trouble to explain things so well and make easy for others to follow
ironically the easiest way to make the SSR redundant is to add another SSR :D daisy chain them and you're golden, risk is significantly lowered. To be honest however, I think that the thermal fuse is good enough considering the plate is hard mounted to aluminium extrusions and not really a fire hazard. The keenovo heater can run flat out at it's rated power like an enclosure heater until the fuse pops. Placing two fuses in series does make sense like you mention and I agree - testing that they work is very important. Have you installed an RCD in your printer? What's the easiest way to achieve this? - A recommendation could be made to the voron dev team?
@@justindelpero there are drawbacks of doing it that way. for a start decent SSRs cost money (up to $50 even). which is pretty expensive. and 2nd to that, if your control board does not detect a failed stuck on SSR.... then it keeps going for some weeks. Then you could end up with the redundant SSR then failing later on in the same fashion. When you already have 1 SSR to PID control the bed temp. Then you don't need a 2nd SSR for any rational reason. You should instead use a regular on/off relay in series. As I have already mentioned above here. Since those are much more reliable, can be active-on (safer way if signal is cut). And if they fail they usually fail open circuit. The cost? about $2 vs $50 for a good one. And safer too. But you would have extra SSRs for multiple individual other heating circuits. For example PTC heaters, filament driers, etc. In each case you should series a regular relay with the SSR (and have that relay being controlled by an mcu that monitors the SSR and can detect if it has failed).