Stronger 3D prints with Vapor Smoothing?
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- Опубліковано 4 жов 2024
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Does vapor smoothing increase the strength of your 3D prints? I've tested this with acetone smoothed ABS and Isopropyl alcohol smoothed Polysmooth/PVB. I printed test samples smoothed half of them and analyzed how the smoothed surface influences the mechanical properties of the parts!
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CNC Kitchen okay
Please test what happens to the strength of the parts when you rotate them sideways (along the Y Axis) at difrent angles (im thinking of something like 10,20,30,40,50°)
I would test it my self but i dont have that much money to spent for filaments
MFG my german friend :D
What about leaving the top and bottom exposed so more surface area could be smoothed I.e. have the infill smoothed as well. I know that what you did is how the smoothing would normally be used.
@@hustlezockt663 _888
Similar to what John was saying, use a gyroid infill and open the top and bottom of the part so the entire interior and infill can be smoothed. Then you might (might) see something slightly more significant.
I know a few people already said it but it's great to have someone using a genuine scientific approach to testing rather than just giving opinions. Keep up the great work!
Stefan is far from alone in being scientific about his Tests but he does apply reliable methods which make his Results & Derived Conclusions very valid & 'watertight'.
If you like this kind of content, ProjectFarm does somewhat similar testing, although for a different audience. He does scientific testing of tape, epoxy, gas alternatives, oil alternatives, all kinds of neat stuff.
Yeah it’s a lot better than reading someone pushing the same Bs myths in the forums and comment section
He is a credit to the stereotype of German attention to detail.
Damn, Stefan is always answering those questions you didn't know you wanted to know the answer for
Good job as always
He's so good you don't even get to think something to ask
His videos only last 20 years but yeah sure pretty good.
ZecoRho it’s 11 minutes and you can skip
@@MarkButQuestion if you can't handle a 10 minute video then go back to UA-cam kids
@@vincentgarcia6630 cry more
Oh man was waiting for such a video for ages for clearing the doubts. Hats off to you Stefan
how about vapor smoothing and then bake them in a relative low temperature to recrystallize the plastic structure and evaporate the deeply penetrated acetone
I think you could achieve the same thing by leaving them in the sun on a high UV day.
@@mortarriding3913 UV breaks down all plastics.
That may work on metals but not for thermoplastics. Their properties decrease when you heat cycle them. A good example is SLS printed polyamide which can only be heat cycled a couple of times before the entire build chamber has to be replaced.
@@ChrisCross97 this isn't true. Cooking PLA makes it substantially stronger.
@@ChrisCross97 it's well proven that annealing PLA prints makes them stronger and more temperature resistant (just search "anneal pla" and see yourself)
I don't even own a 3D printer (yet), but I love your thoroughness and the scientific approach that you apply 😁
Same
Ditto. Clarity backed by the confidence that a Test has been properly done with as many non Test variables removed or accounted for makes for great Credibility.
If you like this kind of content, ProjectFarm does somewhat similar testing, although for a different audience. He does scientific testing of tape, epoxy, rust removal methods... all sorts of potentially useful testing.
From my experience: YES, there still is very tiny amounts of acetone left in the part, right below the skin. If you put the ABS in boiling water the acetone will try to escape the part and form a bubble-like texture, pushing aside and stretching the smoothed skin but without being able to break it. Once it's in there there's no way to get it out, even after leaving parts in a vacuum chamber for 24h.
Edit: putting the smoothed ABS parts in luke-warm water and slowly raising the water temperature does seem to remove most of the acetone stench, and if done slowly enough avoids getting the parts bubble up with escaping acetone vapours. Haven't tested the effects on strength. Noticed slight shrinkage of the parts after boiling.
Even if you were able to remove all of the acetone, his results did show that the treatment effects are only at the surface. While visually, it looks like your strength should go up, the area you are affecting is negligible and any strengthening you do achieve will be small at best.
Should be pinned.
For the weakening of your horizontally printed samples - Extruding creates polymer "fibers" chains that are aligned along the path of extrusion, creating strength in these directions similar to the thread on your shirt. By allowing the ABS chains to redistribute themselves by dissolution and reforming from acetone, you've weakened/removed the structure that was providing the extra strength.
The polysmooth looks to be made of PVB, but I can't glean too many other things from it without really digging through the datasheets.
Great analysis.
I have done a lot of acetone ABS. A few note to consider if you re-visit this.
* 3 weeks is not nearly long enough. In some cases it takes more than 12-24 months!
*The parts shrink. In some cases I've had crazy cracking all over part 20 months later. This can be repaired with a coat of ABS+acetone juice from the same roll of filament. It seem to last much longer, with some prints now 5 years after cracks repaired. This makes me think better smoothing or chemical annealing possible with some plastic in the vapor!!
*temp and time are huge variables. High temps for low times seems best for smoothing, and does not crazy crack later. I like 60c boiling acetone bath and suspend part over boiling fluid less than 10-20 seconds. This needs 8 - 24 weeks to dry halfway.
For more strength the colder slow method is better. It smooths much less but acts more like annealing. Cool room temps, Paper towel, less than 1ml acetone per gram abs. Add more acetone daily for 2-3 days. Much less time for not solid parts. Maybe 3-4 hours for a 3 wall Stanford bunny 10% infill, too long and parts sag. Less acetone can also get you more time with delicate parts if you not getting good penetration. These parts take weeks to firm up and years to fully harden, they love to crazy crack but they are strong like injection molded part. I think multiple treatments over period of months might prevent the crazy cracking. The surface dries so much faster than the middle... Need to cure more evenly...
*I have used a brush to work acetone or ABS juice/paste into cracks and gaps on many parts. It usually dries a bit frosted looking. This is easily fixed with a few seconds of high temp vapor as a second treatment. I get best results waiting at least a week between acetone treatments. Otherwise you can accumulate too much in the part and it shrinks violently and dies unexpectedly sometime later. Or just stays soft and saggy for days. If done well, these parts can be incredibly strong. Although sometimes more brittle, I think the plastic is altered by removal of plasticizes. Less acetone and longer times helps here.
*I've not done much of it for a few years due to discovering how long the parts take to cure, I'm still observing some and want to more sometime.
*Some of the very deeply treated parts I still have are crazy strong. They seem lighter. I wish I had measured the weight more!! Could help identify cure times!!
*I think some of my parts are still shrinking 5-8 years later! Some good quality controlled environment long term tests would be very interesting.
I also do a hot vapor bath over boiling acetone and noticed the finished parts are much stronger without the layer line weak points.
I haven't done the slower smoothing process, so I'm not sure what you mean by the crazy cracking, but I agree that deeper acetone penetration and drying faster on the outsides is the culprit. It makes sense that the acetone absorption would act like annealing too, but hard to control the process of removing the acetone in a reasonable amount of time.
I wish he would repeat these tests with the hot vapor and waiting longer for curing afterwards
Hallo Stephan! Greetings from America! To boil out the acetone you’re must raise the temperature of the hook samples to at least 56.08 °C at 760 mm Hg for perhaps an 8 hours then allow them to cool. Same goes for the isopropyl smoothing: 82.3 °C at 760 mm Hg are your values. This should ensure the solvents have been evacuated. Unless you think the temperatures could affect tempering of the substrate. Then maybe try both at the higher temp. Thanks for your pioneering efforts in your videos! Looking forward to the next one and your thoughts. Cheers from Nashville, USA.
Since it only seems to affect the outside layer, I think a good test would be to print the models in vase mode. Single wall, no infill, would narrow down what you're actually testing now that we know it doesn't extend any deeper into the parts. Thanks for the video.
Thanks for clearly demonstrating how smoothing is just good for aesthetics.
And hiding (smoothing)a point of rupture doesn't change a bit. It is still a point of rupture
For people looking at printing with polysmooth, you dont have to use IPA for smoothing but can also use ethanol which is easy to find in any supermarket.
Congratulations on 100k. You are not just sharing your conclusions, you are sharing the whole process. Your method is scientific and many of us share to your videos as references. Thank you for your devotion
Stephan thanks for testing this and congratulations for 100k because you deserve it very well 💟
Super cool man. I'm impressed with your analytical ability.
Again a great video!
Nicely tested and analyzed!
This guy is so nice and friendly. I'd let him babysit my turtle!
Yay, the first person to finally state what "dangerous" substance is used to smooth PLA.
points to Stefan and many negative points to all other Edit* 'Outlets of information' that have danced around that information.
I've also heard of people suggesting dichloromethane as potentially being able to do it, as it's able to "weld" PLA just like acetone with ABS, but it's fumes are INCREDIBLY dangerous; it's really good at causing you to pass out, and if it doesn't make you die on the spot, it'll give you cancer later.
I also heard that you could do it with MEK just like you would with acetone. Never tried it though...
Both DCM and MEK are pretty fucking dangerous, no need for the quotes. Usable, but you *need* to know how to handle them and be far more careful, even just using it to weld parts, let alone vapor smoothing. Acetone on the other hand isnt dangerous within reason, and anyone could do it safely with a quick youtube video
OsmeOxys "pretty fucking dangerous, no need for the quotes" He was using the quote because he's quoting someone. He says that everyone says it's "dangerous" without stating what substance it actually is. I use quotes to because I am quoting something, not because I don't believe it.
@@LoganDark4357 Correct!
I'm going a little further to clarify my point, yes these chemicals are very dangerous, but when one simply tells people something without explaining why, they usually try to go out and do it, like "Don't look down."
It's more responsible to say, "Chloroform can smooth PLA, but the risk is very high as inhalation of chloroform vapors can kill your liver and kidneys; and short term mishandling also presents many obvious, serious, risks, _especially_ if you are alone."
It's sad, but there will _always_ be people who do stupid things, but it's better for information to be freely available for people to make educated decisions on their own.
I love these videos, I've watched about an hour of them in a row by accident!
Wieder mal ein klasse Video Stefan und herzlichen Glückwunsch zu den 100k :-).
Vielen Dank und Dir auch noch herzlichen Glückwunsch zu den 10k!
CNC Kitchen Danke :-).
Super interesting! Thanks for all these tests! Congrats on 100K it is well deserved. Mahalo! : )
Welcome Hawaii, waiting for next season of 50
Congratulations for 100K!
Thanks for testing. Love it when "common knowledge" is shown to be a misconception.
This fascinated me in my mechanical engineering study.
Polished shafts are stronger than rough ones, as the small grooves on the surface act like predetermined breaking points.
This definitely is true for metallic parts, but with plastic, there is a lot more chemistry going on.
Also, this effect should be more considerable with brittle materials, instead of ductile ones.
I know it’s 4 years old, but still a useful and informative video. Thanks!
Awesome. I just bought a spool of the PVB filament through your affiliate link to smooth models with IPA instead of acetone. The strength looks good, too. 👍
smoothing looks nice anyway and is a step closer to getting a usable mold from a printed part. Thanks for this great vide
Thanks for doing this :) I have yet to try acetone smoothing ABS for the surface finish, but I'm glad I know more about the functional properties that change now :) !
You are amazing dude! Good job. We all appreciate you.
Execellent study. I love the addition of the standard deviation on the graphs!
I believe that the best way to achieve proper penetration with any of your smoothing chemicals is in a vacuum chamber not sure what pressure or what time limit.
But after significant drying time to ventilate most all the chemicals, may vary.
Then followed by oven drying till all chemicals are finally removed.
All 3 processes will be needed to achieve significant penetration and removal of secondary chemicals.
apreciate the Tests
really expected smoothing to increase the strength of the parts
guess that shows how little i actually know about what goes on inside plastics
Could you do a video where you use everything you have learned to print the "ultimate test hook"
me and my friend just fixed his dad's cnc. he printed a panel for motor/endswitch connectors. ABS 100% infill vapor smoothed it is indestructable and we had to buy new connectors
I recently saw an experimental HDPE filament available on a Canadian 3D printing website. You should test it out, the reviews said that it was hard to figure out bed adhesion but that it had superior layer adhesion, and while it is a hard material it bends rather than breaking.
I haven't used ABS in a few years now, but when I would hot or cold acetone vapor smooth parts I would notice some pieces would form white fracture lines along the layers. Almost as if the softer outer shell was under stress from the infill of the parts that were not affected by the acetone. I'm not sure what the real reason for it was, but i definitely noticed different brands of ABS did behave differently in this regard.
Awesome, thorough work as always Stefan!
I read somewhere, that it is assumed, that acetone takes water into the ABS, that aligns between the molecules and therefore reduces the bonding of the polymer strings, basically like an additive. If you have a precise scale you should notice a few % weight gain after drying off the acetone. I'll ask my coworker next week, if he remembers the paper.
9:42 Ahhh... I can see you actually did your statistics. That's appreciated.
Thanks stefan !
I think to be sure that the solvent is 100% removed, the only solution is to create a vacuum chamber... This technics is used in the space industry for composite materials (to remove solvant but also gases, moisture etc..)
I was wondering what dangers to the vacuum pump seals there are from these airborne chemicals?
Thing also to remember is that as the air pressure goes down so does a chemical's boiling point.
You could maybe just have a open container filled with the smoothing agent at the bottom of the chamber, vacuum out the air, let sit for a time, release the vacuum, remove from smoothing chamber and repeat the vacuum in a chamber with no smoothing chemicals present except for those on the 3D printed item.
That should remove any remaining active chemicals.
I like the idea of the lowering mechanism, just make a easily removable plate so the items can be moved from chamber to chamber without having to remove the items from the plate.
With a large enough set of chambers maybe you could just place the printing plate from the 3D printer right into the chambers directly from the printer.
I would have to figure out some sort of venting system as I live in a retirement building. I maybe old but I'm still Evil.
Thats a real research project, thanks a lot, this confirm what I thought, my smoothed abs parts are easily broken than others
You have taught me soo much about printing thank you! 🤝
OMG, I'm not crazy! TY CNC Kitchen! I've been saying for a while that acetone smoothing makes ABS weaker, but to no avail! Stefan, I can absolutely confirm all of your results, and your conclusions, from my own experimentation (w/ABS). If you want it pretty, smooth it, but if you want it _strong,_ don't!
Congratulations on the additional 29K subscribers since June.
Not what I'd have expected, but this is great to know!
I'm still going through your back list, so this may have been covered. It's a bit off-topic from THIS video, but please bear with me.
What if you print alternating lines of X at two different heights, so that the first layer came out looking corrugated, then continued this pattern with subsequent layers, only smoothing out the top-most layer?
Like a plain-laid brick wall laid on its side.
I'm not talking about texturing the surface, but rather the layers. I'm talking about increasing the number of neighboring lines to any line, from effectively 4 (corner neighbors presumably don't count much for strength), to 6. Creating a cross-section of lines that resembles a honeycomb rather than a rectangular array of rods.
I understand it would play havoc with overhangs and bridges, making support structures necessary in some places where they hadn't been.
I have some experience on Polypropylene (PP) material compatibility testing with organic solvents. You might still have Acetone in your parts. If you weigh your parts with a laboratory grade scale you will probably see that the parts are still more heavy after 3 weeks of curing, than before the Acetone treatment. It might irreversible diffuse in the material and almost never leave them. Also curing them in an oven at relative low temperatures will likely not drive out the Acetone completely. It is also not uncommon for plastics to lose some of their mechanical stability permanently after being in contact with solvents (especially really strong solvents like Acetone). This is also true if you are able to drive out all of the solvent that you had in the plastic.
Hi Stefan great work , I've Primary used the smoothing process on 3d prints that are used in flow testing( Manifolds and ports). The smoothing process as you said reduces roughness for friction factors, more importantly it reduces porosity of prints considerably, hencerework to make them airtight is almost eliminated
I know this is an old video, but I have worked with solvents and from what I've seen and experienced once you introduce a chemical that has a chemical reaction that chemical either changes the actual chemistry of the material, or it resides in the material for a very long time. Things that interact on a chemical level tend to bond very well. You can't un-bake a cake.
I use Dichloromethane (DCM or methylene chloride) for smoothing pla, it's easy to get but need some precaution when using such as a well ventilated area and gloves, it gives amazing result though
Great Video. I think it would be interesting to see how objects printed in vase mode would be effected by vapor smooting, because they have a lot of surface area relative to their volume.
Thank you for the hardcoded ad!
I'd love to see a video that summarizes and demonstrates the strengths and weaknesses of different materials. It seems like a lot of people don't understand how weak materials like petg are to impact and shouldn't be used in some applications.
Great video!
Generally the strength of smooth parts is reduced as the smoothing process uses a solvent to dissolve one of the chains in the plastic, this is the styrene in abs. Once dissolved it is no longer part of the ABS chain which is why the stiffness goes down along with the strength, without significant heat the bond won't establish itself again and is also why the surface of the part smoothed never becomes properly hard to the touch again. A small amount of the dissolved plastic will also evaporate with the solvent and if acetone wasn't dangerous enough to be breathing in, the new compound evaporating is much worse.
For vapor smoothing the pla, you can use ethyl-acetate (Tom sanlader talked about it in his nozzle video) that ils easy to use like acetone
There's quite a bit of conflicting information about ethyl acetate out there. Some claim it works well while others claim it doesn't work at all. I guess the jury is still out there on this option.
Have you already tested the effect on strength or layer adhesion when printing parts layer by layer instead of completely consecutively? If you print 6 parts in a row, the previous layer on the first part has already cooled down a lot more than when you print just 1 part at a time.
Waw What a surprise. There is clearly more surface adhesion and reduced stress risers. I wonder what happens. Maybe moisture and alcohol/acetone gets locked in as the surface drys. Hum more test! Thanks Stefan!
Congrats on the subs! I love your videos! This was really interesting!
Acetone is known for removing softeners in any kind of plastics, making it brittle. One of the reasons, why we were always very cautious to use it in yacht maintenance. You really, really do not want that with the hull of plastic boats... ;-) So, the loss of strength comes as no surprise. If you just want a smooth surface, a short exposure time (like a dip or spray) would be likely to help against a loss of strength. Acetone is a beast and healthwise, I would not consider it particularly safe to handle. But handled correctly and avoiding the fumes, it sure does a thorough job.
I think you ought to try vaccum drying smoothed parts.
Yeah, and maybe some baking too?
Intensive tests, pleased you have 100,000. Great Channel
Congrats on 100K!
Congratulations Stefan on the 100K !
Good test, and I am looking forward for repeating Your tests with "smoother brush applications".
This is not the same as "Vapour smoothing", as You may already have guessed, mostly because the brush application - is not even, and more than that - it is unevenly useful for some 3d-printed partd.
Acetone has a boiling point of 56 °C and isopropanol has 82 °C, so it is to be expected that there is still a bit of this substance bound in the material, unless it is backed above the boiling points for some hours.
Try this! After letting them offgass for 72 hours anneal them in the oven for 2 hours (around the glass transition temperature). Furthermore let them cool to room temp in the oven or a drying kiln! Otherwise it takes 6+ months to really offgass and the resultant plastic still behaves reminiscent of wet filament.
I haven't been able to formally validate it, but my working theory and experiences suggest that the solvent gets readily replaced by moisture and/or results in fractured bonds. Forcing whatever solvent that remains out at a higher temperature and encouraging the material to reform it's bonds results in significant structural improvement.
0:14 he finally said hes name right ..GLORY !!
You should try vapor smoothing of ABS in a pressure pot, to see if you can get the acetone to infuse and join the layers.
The results on the acetone smoothed ABS make sense since acetone eats ABS and ASA. It seems as it evaporates it leaves behind deterioriated plastic to solidify again. I can't imagine something getting stronger from being eaten and deteriorated.
Very cool experiments.
I think it could be cool to run some of the procedures in a vacuum - get all the air out of the part, then bring in the acetone vapours in a closed chamber. The atmospheric pressure would force the gasses further into the part. After the smoothing is complete, then store the parts in a vacuum to help the parts offgas.
Nice work Stefan. If you have a very accurate scale it will be nice to measure the weight of the parts before and after smoothing. It seems there is penetration of the acetone in the walls which although it improves the fusion it seems to weaken the whole structure, hence the gain is not as much as many expected.
ABS and SBS parts are significantly strengthened after treatment with acetone, but it takes some time to dry.
I've not worked much with ABS, but I know that acetone can cause problems with acrylates which is why it isn't commonly used for solvent welding. The joints tend to be brittle and break easily when compared to other solvents such as dichloromethane(DCM). Unfortunately, DCM is a bit harder to come by than acetone but methyl ethyl ketone(MEK) can be found pretty easily where I live so it might make for an interesting comparison. You could also try paint thinner or any 'plastic cement' that flows freely like water. Don't know if any of this has been tried, but they should all work on ABS and possibly a lot of other polymer types so long as it is PE/PP based.
And if you are feeling really adventurous, you could try the polishing in a vacuum chamber (think walled glass of metal only). Place the parts in, evacuate as much air as possible and then backfill with warm solvent vapor to see if you get better penetration. Once smoothing is complete, heat the chamber @ 60°C under vacuum for a few hours and you shouldn't have much of a problem with residual solvent.
I love the production quality and thoroughness of your videos! Why are you not bigger?
Acetone entrains water which could remain in the plastic with residual acetone. You should distill the acetone to achieve pure acetone (~100%), and then desiccate the smoothing chamber, at an elevated temperature (~30-40C), to remove all the humidity. Then, store the part in a desiccated, convection chamber (a fan in a cardboard box/plywood box with silica/alumina powder packets) for 3-weeks to remove most of the acetone in the part. Finally, bake the parts (35-40C) for a week to flash off the residual acetone in the plastic. If you flash off the acetone right away in a thermal chamber the surface of the plastic parts will bubble and ripple. Make two controls for comparison.
If you get the same results, then it could be that the acetone has messed with the polymer orientation/morphology. If not, then it could be that the water, or spome other contaminant, has embrittled the plastic.
You add holes so acetone can smooth infill. Or print without top and bottom layer then smoothen. if you consider it matters to strength to 3d print.😇
I guess it would be a nightmare to dry the acetone inside the prints, but maybe it's worth to try!
@@rizalardiansyah4486 may be infill structure and infill persentage also matters such as qubic infill, groyrod infill or many mores for drying out acetone.
I think it would be interesting to see the impact on strength if the infill patterns weren't lined up which creates fracture line weakness. Has anyone done that??
sounds like we need a slicer that generates a 3D labyrinthine infill pattern with just 2 ports to exterior for passing vapor, smoothing the whole support structure!
How would you control solvent effect on unseen internal structure when you've varying strength of parts beneath Infill Surface Areas? Eroding 0.01mm from around a 0.4mm extrusion line has much higher impact on it than removing the same amount from a 1.4mm bit due to PiRSq. In seconds you could irrecoverably destroy internal structure. How would you judge how long to leave the Infill Structure exposed to Gaseous Solvent when every model is different and when excessive erosion of already weak parts could break connections rather than 'plastic weld' strengthen them?
hmm.. I'm not sure on that one, probably needs experimentation. maybe plug the ports while smoothing the exterior then pump a controlled concentration of vapor through the support structure for varying amounts of time and strength-testing to get it dialed in. as long as no material from the structure is lost and it just temporarily re-softens to strengthen the bonds?
Hey Stefan. Would really appreciate a few more videos on PETG. I think it make sense since it is one of the best and most accessible engineering material where the mechanical properties matter. I have found that PLA and ABS can warp or shrink, however I am getting superb dimensional accuracy with PETG, that is why I am asking
PLA Warping? looool
@@alejandroperez5368 not really ... PLA warps a surprisingly large amount.
@@Anonymouspock It warps if you're doing it really wrong. Like setting a different bed temperature for the initial layer, which only noobs would do.
The infill densities change orientation depending on what axis you print on. You need to use a 3D infill pattern that is symmetrical on every axis in order to have a fair test result, or even better do smaller hooks with 100% infill.
Great video. I expected having the layers melted into each other with vapor would have made them stronger. Your results show that either the vapor is still inside the plastic making them soft or its changed the structure of the plastic and it will never be strong. It would be good to test the following:
1) Retest these parts with vapor smoothing but maybe bake them in an oven at low heat for many hours helping remove the vapor from the plastic or let them sit for 6 months and see if the results are the same!
2) Trying printing with hotter settings and smaller layer height. If you managed 10 degrees hotter and layed the layers flatter with smaller layer height maybe compensate by increasing the cooling fan speed if needed, this could help layer bonding. If you work with a filament and maximize the heat this should give the strongest parts.
It is possible that the issue for the ABS parts was the 20% infill. Acetone may have infiltrated the internal voids and did not fully escape.
Congratulations! Well deserved
For the extra brittleness after the smoothing; maybe weighing the part, smoothing, then weighing again.
May need more dehydrator time.
If after that is solved, I wonder if having a mister by the print bed, that sprays lightly each layer as it prints, would make better layers.
A slower print speed and the heat should evaporate most of the solvents, but the print would need a curing time probably much longer than smoothing to get it all.
Could’ve printed the hook in 2 pieces and put it together using acetone to meld the peaces together to test how strong it bonds. would be an extreme example to see if it helps or hurts by seeing if it breaks at that bonding point or elsewhere
Kinda cool to see that welding plastics involves heat and force, if force (like in FDM printers) is missing, layers wont adhere properly.
When I am welding PE or PP (Warmgasziehschweißen) at work the welds will almost be as strong as the base material.
If someone is too lazy to watch, here => 9:55
What if you were to not print the top and bottom layers, allowing the vapor to flow through the infill?
Being that the smoothing only affects the outer layer, I wonder what having fewer perimeters (so that the smoothed layer provides a greater percentage of the support) or giving the parts a section like an I-Beam (to increase the surface area smoothed, while reducing the amount of infill) would have on the part.
I wonder if some time in a food dehydrator might help. Some residual acetone or alcohol might have remained in the prints. Another option would be: 1) dehydrator for several hours 2) vapor smooth 3) Dehydrator I am a newb but learning
Make them hollow or expose the inner structure in some way so that the inside gets smoothed as well, and vapors can evaporate faster.
Very interesting! I thought maybe I was the one doing vapor smoothing wrong that it made the parts a bit weaker and a little gummy...
Most interesting is that acetone on abs most effectively reduced anisotropy - strength is more similar in all directions. This might be a valuable trade-off for some functional parts, though I suspect many functional parts are now printed with resin or SLS anyway.
Very useful and practical knowledge.
would be interesting. Heat treated, then smoothed. See if removing the external stress risers has an effect when the plastic is better bonded
pla can be smoothed with ethyl. acetate. it's a wonderful solvent for pla, acting not too quickly, great for gluing pla parts together with pla-pla bond (ethyl acetate vaporizes out and leaves pure pla), works for smoothing, is relatively safe and widely available at online chemistry stores.
This makes me curious to see the impact of other solvent smoothing methods.
I've found ethyl acetate to work well for smoothing both PETG and ABS. PETG is noticeably weaker, and almost rubbery for the first few weeks after smoothing so I would give the parts at least a month to air out. I doubt the parts will be stronger, but I am curious to see how part strength is affected.
You've only tested tensile strength. I'm curious about compression, shear, and impact resilience as well!
You should see if you can blow the vapour inside the parts somehow during the smoothing, to melt together the infill.
I've seen videos about fire polishing cut edges of PETG sheets, I wonder if you can do the some thing with PETG printed parts and achieve better layer adhesion.
I know I have read that Little Tikes plastic toys that have any sharp edges and seams are smoothed with torches before shipping out. I don't remember where, but I read that many years ago.
In the industry they debur injection molded platic parts with heat from IR irradiators, but only the seams.
I think smoothing 3D printed parts with fire, isnt that good of an idea.
Because the melting point is much higher than the glass transision point, so the part will get soft and wobbly, before you smooth anything significant like layer lines.
It only removes stringing, but that works really good
Congratulations! Your videos are great.
It would have been interesting to see if acetone or propanol applied during the printing process would affect the material strength. This would actually glue the material together not just by heat but also by adhesion.
In my model building times I created an ABS glue with acetone to fix the keel of my sailboat to the body. The material never fully hardened ever since than. And now my boat is like 30 years later, still the material on the glueline is soft.
I guess the material does change it's attributes. While the hardness and stiffness goes down (which you tested) some other attributes like sheer resistance and viscosity goes up. The stress-test for pulling with slight rotation that you tested is not what is enhanced, I think.