Bake your PLA and have it outperform everything else!
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- Опубликовано: 28 окт 2016
- Turn your regular PLA into a performance plastic with this one weird trick!
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Thumbs up for going the scientific route, and including ordinary PLA in the heat treatment test. Unexpected results, that are usable indeed. #respect
A lot of the best results in science were by mistakes, but if you purposefully include testing everything, you sure make it much easier to make those "mistakes". Good going Bro!
that's the difference between legit enthusiasts and commercial hacks peddling a specific product (or every product willing to cut a check)
youtube has gotten quite infested with the latter
Jonathan D that is quite a tightrope to walk and an interesting subject. I am a commercial hack who is also a legit enthusiast, the crossroads are a startup. I want to be genuine, open, technical, and innovative. I am re-using techniques like this and many more to use FDM as a basis for molding and casting an entire wet line of parts for our products. What would be your main points for not making instructional videos too commercial, but made by someone like me who is (or should be) obviously selling something else? I want to make money on our products, not by monetizing our software and techniques, that should belong to the community. Thanks
This XY shrinkage could be an interesting property if you want to heat-shrink a part around a metal part for example. No glue needed and better strength.
Not a great idea. You might not want to mix materials with different thermal conductivity.
@@3dr14ng4 depends on the usecase.
In use cases where thermal conductivity may not matter such as mechanical devices or covers and sleeves for metallic devices, this isn't relevant and considering that most mechanically apt metals are not subject to warping or excessive expansion at such low temps just above boiling water, it's a fantastic idea you acquired there, good thinking!
Like shrinking the handle around the tang of a metal blade
I recently reprinted the broken handle of my espresso machine (witch gets around 90 °C) with PLA. At the beginning i thought this was a bad choice because it became very soft the first time the espresso machine got hot. But after a couple of times heating and cooling down the espresso machine the PLA stays hard even if the machine is on for hours and the handle feels stronger then ever.
That's interesting, maybe heat cycling changes it chemically?
How is it now, Tijn v?
Austin, I think that changing the "architecture" of a material inside it is already the chemistry. Or maybe I'm wrong and it's supposed to be called "physics" :)
P.S. yeah, it was enforced by coffee molecules :D
MoolahNasreddin as are the best things in life!
Tijn v Maybe heat changes the chemical structure of the filament and bonds the layers. Heat treating is an effective way to increase strength and heat capability’s but it will shrink.
@@hazoish7670 Molecular structure not the chemical structure.
Hey Tom, great video. We have been working with Proto-Pasta High temp filaments a lot, and testing them and the annealing process. We found the High Temp carbon fibre needs longer than one hour...up to 4hrs in larger more dense parts. You can tell if it has annealed correctly because you get zero softening at 120 degrees. This rule also applies to their HT PLA. WE make parts that are part of a kit that sits on a hot plate at 110 degrees for hours and has zero warp or soften. We anneal these parts at 75 degrees for 4 hours to get the best results. I wonder if the slower, lower temperatures we use actually increase the effectiveness. Interestingly we also get zero shrinkage in any axis.
I will continue to examine this, and will let you know when our results are online
We are still learning too :-) Keep experimenting and sharing! We will too!!!
Chemically, anytime a crystal is formed, slowing the process down will result in bigger crystals. Which properties PLA cured at lower temperatures exhibits is yet to be seen, but playing with temperature and other factors could produce many useful results. I'm curious about how various vaporized solvents might effect the process as well.
Any method of annealing will reduce induced stress within a material and affects its final dimension (shrinkage and expansion). We normally see this within the PET packaging industry. The most interesting part is the added strength, this would concur with the theory of crystalinity being promoted by the heating process. PLA was originally designed as a replacement resin for PET material (plastic water bottles) back in the late 90's (it failed miserably). The ability to injection mold and then blow stretch would require a fairly long molecular bond, and ability to crystallize. Now how far can it be crystalized? BTW. I left my Proto-Pasta CF parts on their raft on a heated bed up to 110 C. Simply made a small box to insulate them and left them for 2 hours. Reduced to 80C for one hour, and finally one last hour at 60C. This prevented the parts from wrapping.
give that info, can they also be heat treated, or tempered to a degree? With the extra strength gained is a little of that happening to some extent already?
landlockedviking i am not as familiar with Nylon's and their properties. but would i say definitely yes to PETG
now that is a great idea to use the heat bed and a raft. I could see that could exceptionally well
Thank you for the insight. This is something to add to my knowledge repertoire.
That's great info, Fred! Thanks for sharing that, I was actually wondering about staged cooling. Doing on the bed is brilliant! :-)
tried baking PLA few weeks back, parts were definitely stronger but it really only suitable for use on simple shapes, brackets etc..
Shrinkage XY and expansion Z could be due to memory effects relating to each line of deposited filament attempting to return to a more circular cross section as it was in the nozzle. Great work Tom.
Interesting hypothesis! I'd like to see heat treating under a microscope :-)
If you can see molecular chain alignment under a scope, go for it! ;) Just a kind of laymen's explanation here: When the material is melted, whether in a blog on your table or in the extruder chamber and they are not pressurized, the molecular chains can relax and situate themselves however they like....think unorganized like of a plate of spaghetti. Once pressure is applied and it's forced thru the nozzle, they have to all line up while being pushed out and they go with the flow - north, south, east, or west of the orifice....because the resulting layer is thinner than the nozzle opening and cooling happens so quickly, they freeze in the direction they were pushed (or laid out, if you will)...and they always desire to get back to the relaxed state.....it's stressful work staying rigid like that... Once heat is applied again, the closer they get to the glass transition point (not quite melting), they have freedom to relax and that's what they do as best they can.
some things to try:
buy an oven thermometer that sits on the rack. Built- in thermometers are notoriously inaccurate.
fill a tray with corn starch, lay the pieces on that to bake them. It should even out the heat distribution. The uneven surface of the plate used in the video would play havoc with this. You could go further and continue by also covering the parts with more corn starch. I'd try at least 1 cm deep above and below.
I'll use powdered salt.
Awesome video! I absolutely love the whole idea, it has certainly increased the amount of information on the market for filaments by far and is sure to be a handy tool to makers everywhere! Thanks again Thomas!
Cant say how SUPER GREAT your videos are! *Quality* is just great, dont know where to start.
Awesome video. I'm going to try this with my PLA parts. Having the extra strength would be fantastic since PLA is my favorite material to print with. I would also like to see what different lengths of time do, and different methods of cooling, like tempering used for metals.
Brilliant Thomas, always fun to see a theory proven, I love your investigative approach
Just baked a sample of Prusa PLA as supplied with the MK2 @ 110C for 15 minutes on a perfectly flat glass tile (preheated). The part was scrap because of design changes. The test was to determine what level of warp it would get and if there was a progressive effect over time in 15 min steps. After the first 15 minutes the warping affected the geometry so much that further steps were not needed. Z change was +11% over 8mm and in the other planes it was -10.6% over 10mm and -8% over 70mm. One long side had a central protrusion with an 8mm hole with its centre line on the side face, it suffered -11.4% reduction. The part was complex having four other holes in it so it could be expected to warp in an irregular and unpredictable way. The only thing to take away from the test is that longer stretches of parallel filament seem too shrink less than shorter stretches where the proportion of parallel to perpendicular runs is smaller.
Bake it in packed sand, significantly less warping as it is essentially fully supported.
Awesome share Tom... thanks for thinking out the box that's what helps lead to new discoveries
any plastics that have seen some kind of warm passing through a nozzle (extruded parts, water bottle is prolly best example) will show this kind of behavior.
crystallisation and recrystallisation mainly cause the shrinkage. the problem with fillers can be, that they suffer from bad adhesion to the matrix due to shrinkage and then basically act as crack starting points rather than reinforcing the matrix and often have not much use. adding special linking-agents (particle-matrix), e.g. silanisation can compensate for this.
I gotta say I've been LOVING eSun's PLA Pro/PLA+ lately. For its relatively cheap price I've been astounded by its performance and layer bonding....and even if it's not "stronger" you can tell it's many times less brittle. Pieces that would ordinarily suddenly fail with breakage instead bend a tad. And it's a few bucks cheaper than regular hatchbox PLA on amazon. I've gone through two fulls spools of each and I like the eSun PLA+!
First ever video I have seen from you, I am blown away. The depth of testing and production quality is amazing!
I love these short really easy to digest fialment reviews
Awesome Thomas, thanks for sharing. Great idea and very well introduced.
I can say that the PLA parts i printed think it was back in 2012 on my first printer The Printrbot Simple and the parts are still going strong. with the pressure of the pool wall i thought it would break but it proved to be just the opposite. Even a year ago i printed parts to fix my wifes bumper on her SUV and they are still going strong. Gotta love PLA.
awesome! who'd have thought that PLA would perform so well when annealed, thanks Tom! that's an awesome tip, I'm going to do a few tests and possibly stop printing in Abs altogether.
Fascinating to see and hear some of the ideas from metal such as crystallization and annealing, being applied to plastic. Going to have to try this.
Thank you for including the shrinkage and expansion percentages.
It would be interesting to see if printing/annealing with an inert shield gas would increase bond strength.
you must be a welder? Nice idea... argon print cooling... hmmm
It might be a good idea to anneal the pla at a lower temperature to give it slightly improved thermal properties than do a second round of annealing at a higher temperature. Maybe it will warp less?
110 C is 230 F for us dumb Americans.
The shrinking makes sense if you know anything about pizza making or hat making.
In pizza crust, the dough is full of gluten, which is like a whole bunch of elastic bands. If you try to stretch it in a particular direction, the gluten strands will line up and then all retract, making it even worse then when you pulled it. Similarly, the felt for a hat will shrink in the direction you try to pull it out because the fiber line up and retract like rubber bands. In both cases, you have to coax the shape outward by pulling it in circles around the center. You can't really do this with a printed part, but it helps you understand what is going on.
Think of the 3D print as a bunch of fibers stacked on top of each other. These fibers are largely lined up, layer by layer, and will shrink back into itself when heated, but they will also become thicker. So the X and Y shrinkage should be consistent if the shape is consistent. but if the lines are more aligned with, say, the Y then it will shrink a bit more in that direction.
I work in a plastic manufacturer and we do anneal one part and how we keep a consistent shape is we have a metal form the part goes on to keep it to a specific size. So if you wish to do this for your printed parts, you can but you might want to design and cast a form to fit you part onto to keep them from shrinking in ways you do not want, such as moving screw holes too much in a two-part case. This will be a bit easier and more consistent than trying to calculate the amount of shrinkage
Being a 3d printer newbie I was gobsmacked by how strong just plain PLA prints were. Now this!
Different strokes for different folks, I suppose. I get my best results printing in ABS and exposing the parts to a room temperature vapor chamber (fancy name for a polypropylene box - or a box of other materials impervious to acetone (HDPE, glass, etc.)) with a small Acetone reservoir. Just keep in mind to not expose the part for too long; if the vapor penetrates too far the part will deform as it releases the acetone (in my experience, depending on the size and anatomy of the part,
Other people have done testing which reveals that acetone treatment weakens parts. The acetone is incorporated into the plastic, and leaves air bubbles when it evaporates. The outermost shell may seem tougher and uniform, but the interior is more spongy and weaker than before.
That is a valid concern, the physics of it seems plausible. As stated I don't have empiric evidence for my claim, but my limited testing seem to indicate strengthening. I suppose both exposure time and vapor method (hot vs. cold) could be a factor; I find that parts I "over-expose" seem structurally weaker and prone to warping. I also suspect that adding temperature (hot vaporizing) would make the acetone penetrate deeper by virtue of the plastic being hotter, thereby potentially creating complications upon evaporation.
It should also be said that I could be entirely wrong, this has been the case once or twice before. :P
Ultimately, for parts where strength is of the utmost importance I generally make a silicone mold using the 3D printed part and cast the final piece in polyurethane. This of course has its own set of limitations, chief of which is the anatomy of the part.
TheMrBeaton There's definitely going to be a sweet spot for that. Also, the many variables like wall thickness and in-fill will vary things massively!
Makes sense... time/temperature treatment post-production results in greater cross-linking. Which generally yields better mechanical properties. Unless you cook it so much that you degrade it, that is. Covered in Materials 1 in my 2nd year of Engineering, and that was in another Century, in world where I earned my degree in the age when we all moved from the slide rule to those amazing 8-function hand calculators.
How about annealing the parts in boiling water? Seems easier than putting them in the oven, just pour boiling water into a bowl, put your parts in the water and wait for the water to cool down? Should give a very even cooling too, right?
Also your part would only experience around 20% of the gravitational stresses it would in the oven (Assuming you don't have large pockets of air making your part float). This would be great for intricate parts which might deform in the oven. Getting rid of air pockets might be difficult though, but probably not necessary since you can probably weigh them down without damaging them.
As part of an experimental rocket fuel tank, I once tried this process. I have to agree with you, it is definitely a better way to anneal. You can achieve higher and more controlled temperatures as well. Doing it in water also allows you to come down from annealing temperature really slowly and in a very controlled manner; this can increase the strength even more if done properly.
Gravity is a force, not a stress. ;) stress is typically measured as psi or mpa. Anytime you heat and cool parts you're physically altering the parts on a molecular level so you will get some sort of deformation regardless. Boiling in water would be fine if you kept it at a low boil and were able to suspend the part. A turbulent rolling boil would add variant stresses and strain on the part that could cause micro deformations as well as the fact that you're introducing a variant head pressure on the part from the water. I'm not saying it wont work, just saying by removing moving water it simplifies the experiment. The fewer variables, the easier it is to control an experiment. Typically we (engineers) anneal parts in an oven that's computer controlled so they can be in there for long periods of time with a steady temperature change. Definitely changes depending on the material and of course your end goal though and what material properties you're trying to achieve such as ductility, yield strength, elasticity.. etc.
or maybe oil if higher temperature is required
There's actually a guy who made a video, who recommends annealing parts in boiling water then soaking them in COLD water right after for best results. His method is less than scientific, but he claims it works just as well as oven annealing and much less shrinkage. The parts will be filled with water though in small holes and parts of the infill. Probably can dry it with silica.
How about trying vacuum sealing your component in a Foodsaver freezer bag.and annealing in a water bath? Like Sous Vides cooking. the parts will not be in contact with or be affected by the water. A slow cooker springs to mind. Mine can be adjusted for temperature. would the vacuum environment (circa 15psi) help retain the original shape I wonder. Alex Kemmis, I think was the guy you mentioned and the vacuum bag trick would allow you to quench in cold water quite easily. He mentioned ziploc bags which got me thinking about vacuum sealing with a Foodsaver system bag sealer.
I tested normal PLA and petg for a quad build and wasn't happy with either then heard or the tempered/ annealed PLA I gave that a try and is far superior. To get round the warping, when it's cooling a place a heavy object on the top and it flattens it back to normal so in the end it's only a little smaller than the original piece and the minor shrinkage is accounted for. End result is a far stronger and heat resistant quadcopter especially the arms
Wow! I didn't see that coming, but to be fair, I'd never thought about it either :-)
Awesome video and insight Tom ... You really do know how to get our grey matter working.
Hey Thomas!
I'm an undergraduate researcher with Mississippi State University who's currently studying the effects of annealing on standard PLA printed parts. The purpose for this is, as you likely know, to increase viability of additively manufactured parts that are to be put under moderate levels of stress, since the additive method of manufacturing is, without a doubt, the least wasteful manufacturing method. I wanted to thank you for taking a scientific approach to this. While putting together my research literature I have found very few sources that actually include scientific data in their observations and findings on the particular topic of additive PLA annealing. I would also like to ask if you would mind letting me reference this video in my final report and presentation.
Thanks!
Ryan
I am currently interested in moving from ABS to PLA but need the temperature range offer by ABS, so your video was of great interest to me. Based on your input, I baked a PLA box, which is 86x95 mm and with a print height of 41 mm. Wall thickness is 3 mm. Unfortunately, the annealing process caused the box walls to warp and blister with the outer shell separating from the inner fill. However, by encapsulating the box in plaster of paris and annealing below the boiling point of water, to avoid the moist plaster from cracking, I was able to get a usable PLA box, with virtually no warping or blistering. It's dimensions were also very close to that specified in the design.
Given the lid is a flat 3 mm surface, all I had to do to avoid an warping was to cook it while still attached to my hair spray coated glass print plate. There was, however, a 0.6% shrinkage along the print surface x and y axis. Print height increased by 3%.
If you made a cast of the printed part with material that retains its shape under high temps.
Then place the printed part inside the cast as its being annealed, then maybe that would help maintain its original shape. 🤔
This might explain why my PLA Hurricane cooling duct and E3D V6 mount have not failed on my CR-10. I initially printed these out of PLA just to see how well they fit. That was last year and I can tell the material has changed because I can feel the material is noticably harder and denser. I am printing another one out of PETG just to see how well it holds up on my other CR-10.
I'm a 3D printing n00b but was very pleased to hear this. Very informative, thank you.
Maybe you could try baking a regular PLA coil before printing and see if that adds any extra data. I sometimes have used baking on PLA to remove extra moisture. I have noticed that it seems to look differently, but I never tried a strength test to the parts afterwards. If it adds some strength it might be a better option then this because the part won't have shrinkage.
Dry filament definitely gives the best printing result, but don't be misled, heat treating your filament beforehand will not give it high temperature resistance. Melting during printing "resets" the material structure to amorphous and it still needs to be baked to afterwards to crystallize and get that high temperature resistance!
FYI: wood shrinks in the opposite way, more or less, when drying. it's different in all three dimensions. wood hardly shrinks at all in the main axis of the fibers. but here's the kicker: wood shrinks more perpendicular to the tree rings than it does parallel to the rings. that's why plainsawn (when rings tend to run the breadth of the board) tends to warp into a half-moon cross section, as the rings are circular. I know it's not relevant, but I think it's cool.
You should try with several steps in the annealing process : start with a 70C cession, then 85, then 100, and you may even try 110C after that. The shrinkage will still be quite present, but you should avoid any major deformations.
Also, annealing plastic, especially when machining injection molded parts to exact dimensions, seems common enough (at least for industries that do such things) that there is quite a lot of material on the topic. When annealed for this purpose, there seem to be temperature, ramp up, and ramp down cycles for different types of plastics. For example: www.boedeker.com/anneal.htm
It's likely that both PETG and ABS parts would also benefit from annealing, although with different temperature and ramp schedules. There's enough material on plastics from other industries that would lead me to believe that all of these techniques should also apply to 3D FDM printed parts, but I can find very little rigorous experimentation.
I'd like a torsional test and crush, esp as a wrench or bolt head, test. If you could perform those tests It'd be appreciated
Carbon is like wood where it has a grain structure. Especially when printing it vertically. If you printed this part horizontally the carbon should out preform the other plastics. Of couse this is for regular carbon fiber. Idk if the same applies to printed parts. But having your grain aligned with your forces properly should add strength in the dimensions you need while it will be weaker in the other dimensions.
Pack it in the sand to add compression force to allow filament to bond. This is common post processing techniques done on metal SLA printing. I am assuming same practice can be done on FDM plastic parts.
I will have to try this myself. Thanks for the idea!
Just did my own tests with Makergeeks' HTPLA and some generic PLAs, and I can confirm, normal PLA sees huge improvements. I was worried about making a coffee cup out of PLA for obvious reasons, which is why I went for HTPLA, but after annealing the regular PLA in my tests I am seeing that it could handle near boiling temperatures just fine with no warpage or softening.
wow good to know all round info . great vid man.
Very interesting! I'll try this technique on some 3d printed hair sticks. I break my regular 3d printed ones too easily and the shrinkage doesn't affect the function whatsoever.
This would be a great use for a PCB reflow oven made from a toaster oven. The ability to expiriment and dial in different profiles for different materials would be great.
Thank you Thomas.... That was a great contribution
An idea that I have to do annealing, do not test yet, is to put for several seconds in boiling water, remove it and put it in cold water, put it in hot water for several seconds, take it out and put it in cold water. Repeating the process many times, it is that the interior of the object does not acquire temperature, and only do it much after the outer walls and if they are consistent and endure more temperature. A way to do the annealling step by step without deformation, "this is theory by now".
That is really interesting. Cool discovery! Appreciate the testing rigor as well. Will definitely try this out.
Personally i do not think that annealing will have any bad influences apart from possibly some degradation of the polymer. (Should not be noticeable if the annealing is done carefully, but it probably does influence recycleability of the PLA) Apart from that, i actually expect the PLA to be more resistant to moisture, as crystalline molecular structures are stabilized.
Hi Tom,
I am a 3D printing enthusiast from the USA who just bought himself a Prusa i3 MK2 (courtesy of your video, actually). I have a fairly large list of filament manufactures I want to test and show. I also thought your test system was easily the best. I just wanted to ask your permission to see if making videos in the the same format was OK because I don't want to look like I'm copying you and not giving you any credit or anything.
All the best,
Daniel.
Guess you never pursued that
The carbon fiber reinforced parts did not actually anneal at 110C, the fact that they are black means that they actually end up somewhere between the temperature of the air and the temperature of the heater elements., as a result of their high emissivity. This may also have made the green part get hotter as well. In order to fix this issue, I have wrapped parts in aluminum foil to ensure that they are not being directly hit by the radiation from the heating coils.
I think I know what you're doing wrong with the CF parts. Any fiber reinforced material needs to be loaded in tension parallel to the direction of the fibers (i.e., the layers). I think if you printed the first part in the weighted strength test with the largest face parallel to the bed you would see the benefits.
To be more detailed, the fiber reinforcement only does any good in tension. (just as a steel cable only does well in tension). When a beam (such as the first weighted test part) bends, there is tension at the top and compression at the bottom. However, due to the printing orientation, no fibers are actually bearing the load, only the adhesion between the layers is. Even after annealing this wouldn't change anything because the direction of the fibers is still orthogonal to the stress.
Feel free to inbox me if you've got any other questions! Hope this helps...
Could you do a video about best infills, filaments, and printing method for part flexibility instead? I am dealing with orthotics and would like to print insoles with SLA (resin), but I am struggling with creating infill patterns in SLA slicers (trying to design my own metamaterials in CAD instead)
i printed my part cooling fan in pla, i heat cycled it, started at glass transition temp or just under for 5 mins and let it cool,then raised the temp 15 degrees and did same till i reached 110 its been fine for months now i little shrinkage but not as bad if you just hit it at 110 straight away
To prevent sticking, use a powder coating product called pre-release. Also unless you are trying to apply a texture to the part, use a smooth flat surface.
What material do you recommend for powder coating?
@@RyanR3STL3SS Material to coat or material for coating? You can coat any material that withstands 350° in an oven, and for coating there are powers available in many colors.
Eastwood and Amazon have a wide selection of powders.
If we anneal the parts still stuck to the build plate, the xy shrinkage should decrease and limit warpage. I will test and let you guys know.
Hesitate to draw any firm conclusions. From my experimentation it seems like different companies use different source materials/formulations for PLA. Even when I was trying to smooth them different brands gave drastically different results from treatment with different chemicals like ethyl acetate, M.E.K. substitute, tetrahydrofuran, acrylic cement, pipe cleaner, dimethyl carbonate, etc etc. Doesn't help that even the chemical manufacturers add different things in their products.
230 F for 1hr (i might try 40-45 mins) (also might want to start with a cold oven- so they evenly get up to temp)
Thank you for the video, this was an interesting watch.
I'm Sure that every material needs its own temperature and bake time and possibly several cycles of annealing and you could achieve stronger parts without shrinkage. Pick your favorite material to print with then experiment away. Share your results with others and help advance the 3d printing community.
I wonder if the gain in strength is due to the fact that it increased in size along Z-axis which is where you are applying force to break it? (shrinking in size is also making it more dense)... Good video as usual!!
Which Brand was the standard PLA? dasFilament?
I'd love it if you did more on this. Tests for how consistent the shrinkage is would be a great start, and testing a variety of temperatures and times would be good too. I'm curious whether short cycles of heating to the glass transition temperature, then cooling, then heating again might reduce the amount of shrinkage seen or whether it would just worsen overall results.
I'd do this myself, but I don't have a toaster oven that goes to low enough temperatures, and my printer has problems I'm still working out.
interesting... In the hobby world... we used to "boil" and "Dye" parts to make RC car suspension pieces stronger. Essentially you would take your part and boil at 100c for near 30m or so with fabric dye mixed in water. It made the suspension pieces stronger but essentially they were annealing them like with what you are talking about.
thats good to know.. as i prefer pla above all.. pla is the cleanest and easiest to print... for perfect engineering parts with out the strength.. until now.. a perfect overall filament... the only problem i see.. for exact measurements.. after heated might not be exact to specifications even if altered on software.
Is the shrinking factor a constant? (IE: does it always shrink X & Y by 3% no matter the shape or size of the printed object?) Or does it depend from the printed shape &/or it's size?... that would be interesting to find out with some tests... If it's constant then it should be possible to adopt universal values of pre-scaling the model prior to printing to get the desired dimensions after baking it... just my 2c
Pick your favorite PLA, make different parts of different shapes, bake it and measure. There's no other way to know :)
FranckR I...
...
I don't have a printer... :(
But I plan on getting one eventually.. probably a Prusa. I can make custom models easily though... so yeah :3
Great question, I don't believe that it is. There is an inherent flow of material and therefore alignment of the molecule as they are extruded even under low pressure. A higher speed of extrusion should increase that level of alignment. Therefore its possible to assume that the direction of the extrusion (or flow, say from North to South) of the material will have a greater amount of shrinkage than from East to West. All to be validated and tested. But again, great question.
Fred Pinczuk Yeah that sounds plausible... other factors can be involved as well I think.. like how fast it cools down after the extrusion... that can affect how the molecules settle down..
This was my question too. If you're printing a one piece toy for the kids shrinkage is a moot point, but strength would be a big plus. If, however, you have a multi-part assembly, quantifying shrinkage for model adjustment becomes crucial.
The problem I see is that "doing tests to find out" would be a nightmare. Too bloody many variables! +Fred Pinczuk was on the right track.
What temp and speed was the filament extruded at when made? Cooldown time? Same Q when printed. Was there a fan? How much air flowed while layers were laid down? What was the room temp? (As +Advection357 pointed out - How fast a cooldown?) Bed Temp? Extrusion speed? Nozzle size? Etc, etc, etc. All could affect the results.
Any attempts to quantify shrinkage rate would require many prints, altering many conditions, and the end result would only be totally true for ONE filament from ONE maker, and might even vary by batch. Even just time / temp baking, ignoring all the other possibilities, would require many runs. We're talking microscopic crystallization here folks. Not one plus one.
This test is very intriguing, but certainly not something someone could do at home... perhaps some MIT undergrad team for their thesis ... But a most interesting idea. A home test would be a colossal waste of time and $$ and would not be conclusive, IMHO. :-)
Big shoutout to Thomas Sanladerer for the test, tho. Nice to know your can get a bit more strength, great for certain projects where shrinkage is a minor issue.
2:30 The CF, You printed it Vertically instead of Horizontal. Layer on layers are tend to break on that direction and are on the weakest point. If you print it Horizontally where your test are based upon, you will see the modulus strength difference. CF are known by directional strength.
One thing, CF are isolated by on its own layers, even if you anneal them. it will not migrate to a different layer.
This makes me wonder if other plastics could be annealed too... Like abs and nylon
Yes and no. This is essentially what heated build chambers do for ABS. It "anneals" in the sense that it allows the ABS to relax and remove the excess stress in its layers as it cools uniformly and that will improve its strength. However, ABS is highly amorphous (the reason why it doesn't really have a true melting point) and annealing it won't cause super large crystalline grains either like it would in polylactic acid (PLA). Its chemistry doesn't favor it.
I feel like this is something that needs to be tested lol
for metals there are different methods to improve their properties(these methods developed through time), so it's a matter of time for plastics especially now since it will be used by everyone capable to afford a 3d printer.
You need to be able to control the temperature and cooling cycles to anneal properly. It'd be horribly inefficient to do it in a microwave. On top of that, Microwaves operate on a 2.5 ghz frequency which is the resonance frequency of water and it also interacts well with fats, and sugars, vibrating it and causing heat. Your prints (ideally should be dry) wouldn't work as well as a temperature controlled heated/cooling chamber.
The other problem is that you actually can't set the power level of a microwave, it's either fully on or fully off and controls power by cycling the magnetron. The part could be wrapped with a damp paper towel to heat it, but I doubt you'd be able to control the heat well enough. Considering the size of most printed parts, it would likely be best to use a toaster oven
Very interesting. My gears are now going to get some "special" treatment (well, the next lot I print and size accordingly).
Thanks for sharing the info.
That was a cool video Tom! I will try it.
That's really interesting. I'm going to try annealing some generic PLA and ESUN PLA PRO right now!
Oven is set 250 F. Heat gun says its from 130 C to 100 C.
Test Results: ESUN PLA PRO was stronger. WAY stronger.
Generic PLA was WEAKER.
I'm going to test with ESUN PLA asap
what is "PLA Pro?" Do you mean PLA+?
Richard Dagenais yes, sorry about that. the amazon store when I bought it listed it as PLA PRO and PLA+, they are the same
PLA+ is definitely way stronger. It has 25% deflection vs PLA's 5%.
I wonder if there are any volatile components to the filament. For example, maybe some plasticizer that might evaporate during the baking process? Or even possibly baking out moisture?
It would be pretty interesting if you can find a difference in weight before and after annealing. Might require a scale with high resolution, though.
I guess I would try to find the composition of various filaments, although they might be secret. Possibly talk to a plastics engineer, see what they think.
Try acetone vapor on ABS parts to see if the improvement could be compared with this baking PLA method :D
Thomas Sanladerer try then baking ABS :)
Hi, I`m quoting another post: PLA chemistry favour the annealing process. Unlike ABS which is highly amorphous and annealing won`t cause large crystalline grains, so maybe is not worth doing with ABS.
Maybe it's due to the carbon fibers suspended in the PLA that still promote many smaller crystals to form. Where plain PLA would benefit more from annealing as it would have larger and fewer crystals on average.
Generally speaking most of the advertised high temperature PLAs that mention annealing are using Natureworks 3D850 - the benefits being FASTER crystallization rate (so it doesn't need to be in the oven as long as other resins), and therefore hopefully less warping/dimensional change. It's also one of the first plastic resins that was specifically designed for 3D printing (whereas before a lot of stuff was just 'hey, we make this resin already, maybe it'll work for that 3D printing thing you want to do'). Most of the other types of PLA on the market are Natureworks 4043D. I think it's the carbon fiber content making the prints more brittle, and hiding a lot of the benefits to 3D850 - Thomas should try testing some of their HTPLA without carbon fiber.
Depends if you want max strength or min shrinkage...what about parts where you need accuracy and HT with no load? Depends on application. There is always a trade off and fibers reduce shrinkage :-)
Tom, can you do a video on Sainsmart PVA, recommended settings on your printer and any preparations we should be making for the material (e.g. baking it, etc.)
I dont have the time to try this. But if you do:
I'd be interested to see if I took PLA, and layered it with fiberglass like Plywood, interlocking the fiberglass, how much on a measurable scaale I could increase the strength of the material.
So taking several layers of PLA, and sandwiching Fiberglass in between, and heat treating the material to bond them all together. Also if you got that far in the process, seeing how much strength in the material could be achieved, and calculating the strength gained in the layers proportionate to quantity of the layers..
Cool! I've been needing some thin, mass-produced plastic parts that can hold about 26 kilograms for upwards of 5 minutes over and over and I think this will help.
My concern would be dimensional stability of precision parts, the extra toughness is great but if the part doesn’t fit a tight tolerance situation anymore, it’s useless
Useful information, but I would try to change the hot water test so that it is more consistent. Maybe put it in a device that gives it a consistent torque to see how much it actually twists, or in some sort of clamp that gives a consistent pressure to see how much it actually squishes. Also in regards to the shrinking and expanding on the Z and X/Y coordinates, I would have to guess that this is slightly subjective to layer heights, as those are what helped impose those stresses.
I wish you would have added "before and after" strength tests, perhaps some time in the future?
Very nice! Ypou need to put this new part in your #Filaween series! This video make me think about knife making process , where you firstly quench your knife and then temper it for some hours in oven! Just need to speriment other temperatures and times.
Your parts stiffness increased, but the Yield point stayed the same. This is a great result! I point at the example of ductile steel vs plain carbon steel. why would I want a weaker steel aka ductile then a stronger steel plain carbon steel. well ductile will reach its weaker yield point without deforming, or bending, at that point it breaks. where plain carbon steel will deform/bend and keep that shape without yielding. this is problematic as clearances in mechanical parts change, and don't bring rise to the deformation. If i was making a gear/bearing in PLA. I would opt for the stiffness vs the flexibility. If i was making a snap cover plate, I would want the flexibility for my clips. Thanks for the video!
This comment comes from completely outside the 3d printing world. But crystalization can be improved by slow cooling slower the stronger
You sir, have finalized a decision for me.....thank you
only streching under heat makes the stretch direction stronger and the other direction weaker. hdpe will be stronger
I think for more simple things that don't have to fit together or be tight in tolerance this is great! But I feel like in most cases a different filament choice would be better. When are we going to see some nylon and the like Tom?
hello, this is a pretty interesting video. i would suggest that you try different cooling speeds after annealing. the crystalline structure of materials change drastically if they are slow cooled (like you probably did letting them just cool down) vs a fast cooling submerging them in cold water or something like that. you can also try cool them even more slowly letting them in the oven while it cools. the slower the cooling the crystalline areas get bigger while if you cool them fast you are 'freezing' the high temperature amorphous state.
this is the same thing that is done with glass and metal, never knew it would work with plastic. pretty cool.
Try annealing in got water with different temps. It might prevent gravity effects.
I manufacture a part that needs dimensional accuracy. This part is often left in hot cars which causes them to shrink and become useless. Do you know what material will not shrink at all? Perhaps you can do another test with carbon fiber, nylon, abs, or polycarbonate. You’re the only person on the internet who has done a test even close to what I’m looking for.
I anealed an irregular shaped part in a pan full of white rice to support it to reduce warping and it seemed to work rather well
great video Tom. I am sure it's going to get many comments. good work
might want to try a Sous Vide system. print on some supports and stick it straight in the water after printing. If it works anything like metal or glass, flash at high heat for a few minutes and let it cool off slowly over a few hours. should smooth it out as well.
Also to add strength, try printing with a core of different material.
My Hypothesis on CF (never tried however):
Carbon fiber can give strength advantages if oriented and the the fibers are long enough.
Two things easily obtained with injection molding, stamping or real continue extrusion.
To 3d print you need very small fibers and orientation is along the extrusion direction of the film... son exactly opposite to link between layers that is the weak spot of the print. I'm not expecting a good effect.
Maybe a better effect on impact resistance, or crack propagation slow down.
Hi Thomas. I attempted to anneal standard value PLA in a toaster oven, and the heat may have been set too high. I did this before watching this video. The result was a severely warped part. I did not retry it at a lower temperature, but plan to sometime in the future.
You could do threaded insert during annealing and it should hold it much tighter