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Which 3D Printed Gear is Best?
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- Published on Mar 28, 2023 veröffentlicht
- 3D Printing is incredible, but can you use it to make functional gears and mechanical parts? In this video I test #3DPrinted gears to destruction to find out which filament is best.
Join the Maker's Muse Community - www.makersmuse.com/maker-s-mu...
Tested filaments and suppliers:
eSun PLA+ , PLA-ST and BASF Ultrafuse PLA Pro 1 - www.cubictech.com.au/
Monocure PETG - monocure3d.com.au/
Fiberlogy - fiberlogy.com/en/fiberlogy-fi...
Polyalchemy Elixir PLA - www.polyalchemy.com/
Compositum ABS ST - www.corotechnology.com/englis...
Grab a torque wrench! amzn.to/3reUPOS
TIMESTAMPS:
Intro: 0:00
PLA: 3:49
ABS: 9:15
PETG/PCTG: 10:39
PA/Nylon: 12:32
Conclusion and future testing: 15:2
50 3D Printing Tips and Tricks - gumroad.com/l/QWAh
3D Printing Essentials - www.amazon.com/shop/makersmuse 
Science & Technology
Late to the party, but as an engineer, I feel the need to comment. Gears need 100% infill. Yes, in general, material stresses run higher on the surface, but effectively having a hollow part creates surfaces on the inside as well. The sharp inside corner that the slicer will leave under each tooth combined with the inside corner created by the inside surface of the face will create sharp junction of three surfaces on the inside. This will be a huge stress concentrator. If you watch carefully, this is the first point where the plastic turns white. (Crazing) The second place is the root fillet of the tooth. This stress concentration is inherent in any gear tooth. Try again with 100% infill. Also try setting the top/bottom surface thickness to the full thickness of the gear. I would expect that the diagonalized print lines of the top/bottom layer will act to brace the teeth. Also, I would experiment with the shell thickness. I would expect that would allow the diagonal lines to extend into the tooth somewhat, preventing the delamination/crazing at the root of the tooth. Interesting, but the 20% infill is definitely more of a problem than the material.
A few minutes in and I was also scratching my head wondering why 20% infill was being used for this testing. I'm still a relative 3D Printing newbie, but from what I've seen so far in my own experiments low infill levels work better for large objects and apart from speeding up print times and reducing filament use I've found it can help prevent warping of the base layer during printing if you're trying to print something large and flat. (Like an upside down toy table)
But anything small that needs to be strong and has high force concentration on a small area like teeth on a gear needs to be 100% infill for sure. Hardly a fair comparison against an injection moulded gear which by definition is "100% infill"... While I haven't tested them with a torque wrench I've printed a few small gears with PLA with 100% infill and they seem surprisingly strong if you print them in the right orientation - probably comparable to cheap injection moulded gears.
I'd like to see these tests re-done with 100% infill and no other changes.
also. apply force to the same tooth, many times, gives you differents results of real stregth. good video anyway.
For sure, even at first test with PLA you can see that teeth are just separate from poor infill amount in center
Grineer?
my first impression....was what you said....why 25 % infill...not good....But here is the catch....if your motor is for 20 N-M...then you want that the gear fail first....otherwise you will burn your motor...👀
Infill patterns will probably make a huge difference. Next up, take that BASF filament and try different patterns at a fixed density. Would be very interesting!
A digital torque adapter would be more convenient for tests like this, they are not too expensive either - may be a handy addition! Especially with how useful these tests are!
@LandMarker That was the purpose of the second gear, which was tested to failure at the torque found for the first gear. Not perfect, but a good check on the result.
True. Moreover, using this adapter will give more accurate results. During the test the specimen was loaded then unloaded several times in order to adjust the torque wrench. While a proper test should be carried out in a linear manner as possible until failure. The cycled load can harden the material, through minor plastic deformations, thus getting higher false result.
I’m not surprised by the PLA results. I’ve seen great durability results with many of them. As you found the hex shape is a weakness as it has less surface area for direct force than the gears. But that may give you the slip you want before failing a motor. Great summary and look forward to the other testing you plan.
@enlightendbel Ever looked into PC-ABS or PC-PETG? Both are not as hard to print as PC itself using some kind of improvized chamber and carefully printed on a somewhat warm buildtak style surface. Printed rather tough gears with it before but can't say I have tested them to the breaking point.
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@ItsDane my issue with Nylon is rarely how long it lasts, but the fact it's so mailable that the parts deform in ways that makes your system fail to function while the part itself has no actual damage. For gears especially, Nylons tendency to flex and flex even more with higher temperature, introduces a lot of play and failure states you can't even predict.
But for housings, it's fantastic.
I've found the same printing mechanical parts in PLA, PLA+, PETG and Nylon.
Straight up basic PLA and PLA+ are often stronger, especially if you take the extra time and care to anneal them well. At that point, their hardness is something to behold.
With PETG, the air moisture levels while printing are one thingm but the air moisture level while operation as a functional part also plays a ludicrously large role in performance. I seriously hope someone makes a PET variant that stabilizes it as well, but better maintains PET characteristics, because PET plastic normally is both flexible and tough as nails even when literally functioning as a water container. PETG on the other hand can get ludicrously brittle when moisture is introduced.
PETG does better if you salt re-melt them, but that only lasts until they suck up moisture again.
And with Nylon, for rigid parts, it straight up just sucks balls. It's tough because of its flexibility, not because of its rigidity and it gets even more mailable at higher temperatures.
Nylon parts for me often bent their way out of their intended location long before sustaining permanent damage.
Re-enforced nylon with glass or carbon fiber is tough as nails and fantastic for housings and the like but also not great for mechanical parts. The fibers increase wear to themselves and the housings, bearings, axels and the like considerably.
Key thing I learned however is it's not always the material itself that matters for mechanical operations, but how you treat and post process them.
For strong parts, you're always better doing one or more annealing cycles, remelting and whatever other techniques exist for specific plastics.
Because you are putting stress on the part, it is extremely important, just like with metal mechanical parts, to destress them before using them through one or more post processing cycles.
By having the internal stresses from being melted, printed and cooled, their mechanical properties are far lower than they are when properly post processed and destressed.
Annealing and remelting can also slightly or vastly increase layer bonding which also increases mechanical strength.
@UncompetentTV please keep posting
Taulman makes some amazingly strong Nylon. I have used them for gears in an industrial lathe that was out of production and we couldnt get replacement parts. What was one of the best parts was how quiet it made the machine with nylon gears versus metal. I admit the gears only lasted a few years but considering we could print them for a couple bucks each, we just made an inventory of replacements.
100% infill would be interesting with a decent amount of wall overlap.
@У Егорыча very true. I make competition robots for my university to compete in the VexU robotics competition and we 3d print all our gears and lots of parts. I cannot tell you how my jaw dropped when I saw he was only using 3 walls. His gear teeth weren’t even full infill. I love this guys channel but this is horrible test video because of how little walls he used. He was just asking the gears to break
@DB I mean perimeters count. In PrusaSlicer it is "Perimeters" in "Layers and Perimeters." I don't know how it called in Cura. "Wall thickness" I guess.
@BLDJLN if walls delaminate - it is bad print. Check your printer and print settings.
@У Егорыча hi what do you mean by increase perimeters? what setting is that
@У Егорыча Not necessarily. Walls can easily delaminate.
That's a pretty interesting lineup!
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What ur doing here, nah im kiding, yep this Is actually use full
It's probably also important to test at the speed they will spin at in production for a reasonable work time. They can work great at first but then start to melt.
I really like this video, and the practical setup of your test. I'd love to see a remake of this for a few of the fillaments where they've been soaked in water overnight. Apparently PLA is stronger when it is humid.
I'd also be interested to see how the gears stand up to wear. I understand that your use is mostly for prototypes. However as a hobbyist a lot of the time I'm looking to make a functional (remakeable) part.
What a cool episode! It really makes me wonder if the gear shape we have arrived at for metal is really ideal for plastics like this as well. Maybe a different tooth profile will be way better for FDM printed parts!
Very interesting results! I've been keeping an eye on any updates for your RC platform. Cool to see you do a deep dive on one aspect of it. - Perry
hey ood
@Mizai not just any popular channel, but a 3d printer related channel, which makes sense to be on this channel.
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What filement do u use to print ur 3D printed parts
I have a story for you...
Several years back I went on a tour at a local industry location that creates thread and string. They have a set of all-mechanical machines created about 100 years ago. They are not electronic at all. They all have precision custom parts made of metal except for one essential gear that is made of wood. This was deliberate so that the wooden gear would wear down and break before damaging the other parts. This thin gear is cheap and easy to replace by stamping out a new gear from a thin wooden board. Nobody knows who built the machine but the design is very smart. Take inspiration from it.
@SpinStar1956The problem with these companies now make things so you can't repair them, I don't know about kitchen aid, but a lot of my tools you can't buy parts anymore. they just want to sell you a new one. One of the biggest reasons I got a 3d printer.
@namAehT Things that seem as trivial as vertical reflectors on an airport runway use that technique to avoid damaging the planes if they were to hit one. I like knowing stuff like that since I'm a mechanical engineer, too.
Sometimes a plastic gear is used on the motor that mesh with metal gears to help prevent metal to metal radio wave spikes. RC servos are like that.
@CambridgeMart Some shafts in certain applications are titanium. Good for extreme heat and will not bend. They will snap with enough force. The key in small engine shafts is aluminum or zinc so it will shear to protect the engine.
@blatantmisconception I have kitchen set and several component you can swap have these parts. Like meat grinder, blender and so on - there is plastic link (in otherwise metal part) with clearly weakened part to snap if too much force is required to operate. it is even declared in User manual.
I guess in machine industry once they went from belt to gear driven machines that there is no natural slip if it is overloaded so they added these parts - if they were smart enough.
Awesome video! Look forward to seeing how PC holds up and how going solid will help. BASF is pronounces "B" "A" "S" "F". I had a family member work there, they make several chemical components and are starting to get into filament and resin material.
This was a really interesting watch, thanks Angus. I've been messing with a gear reduction for my Big Mixer project and have been trying to figure out how to deal with the increased torque. I was surprised to see some of my PETG parts fail before PLA, in particular I noticed a significant difference between eSun and Zyltech PETG rigidity.
Most of my failures seem to be at the attachment to the axle, rather than the gear teeth. Your approach with a 12mm hex head might be a better idea than using the axle detent and a 2.5mm screw that I have been using previously. Thanks for the idea!
A big advantage of 3D printing is that you can put one of each material on every wheel and see which one fails or wears out first :) People more knowledgeable than us have already solved this problem IMO, almost every injection molded gear is made from nylon (lubricity and toughness). I've also seen acetal (aka POM aka Derlin), but that's a nightmare to print. I would stick with nylon, and I would avoid the fiber filled varieties, both due to lower lubricity and potential health reasons if it liberates carbon fibers (glass fibers may be safer).
Love this type and level of real-world application testing. This is far more useful than just some numbers on a spec sheet or anecdotal evidence. Thank you for putting in the time and effort!
I would love to see how the different gears handle after running for a day, seems like an important factor in its use
Great insight! Very surprised that you didn't use 100% infill, since your gears are so small. I would print, at least, the top 3 contenders, solid, and retest.
Really interesting! I did not expect that Elixir would perform so good. Also the BASF (Spoken B-A-S-F, it stands for "Badische Anilin und Sodafabrik") seem like a really good underdog filament for structural parts which doesn't break the bank like oder BASF filaments
Interesting! Something else to consider is that nylon is lower friction than most of the others, which could impact actual use. Also, I would love to see some Taulman filaments tested. They have some very helpful charts on their website that show strength and stiffness for their filaments, which could be helpful when selecting some for gears.
Thanks for making this video! I was looking for a good comparison of 3D printed gears all over youtube. If you intend to do further experiments in this direction you could test different gear designs like herringbone gears :D
The pla results are very impressive given the myth behind pla being weak is pretty intresting to me and makes me wonder how pla+ or the eSUN Super Tough PLA for a ant weight combat robot chassis would hold up compared to other 3d printed materials out there like abs, nylon, onyx etc
I've been using a fair bit of Polymaker PC-ABS and more recently PC-PBT (which has been a real paint to print, but it's certainly tough and the temp resistance is very impressive) and both would possibly be really good options.
Can you test annealed PLA? I think the results would be pretty interesting
@enlightendbel Hi！Could you tell me how to anneal PLA? I really want to know
I'd bet it'll be a serious step up in strength.
All my experiments with what's strongest for moving mechanical parts has always brought forward annealed PLA/PLA+ and remelted PETG.
PLA retaining its strength longer while PETG gets more brittle over time as it reabsorbs moisture.
Ofcourse, if your application doesn't have your part in an environment with moisture, PETG will do better.
@Michel I have annealed prints at 100 C with 5% infill and it works just fine, as long as there is no stress on the print as it anneals. It is much stronger and more temperature resistant after. I recommend it for all practical mechanical applications.
@CambridgeMart yeah that is a really good point. Does that mean that PETG is worth it for the long run?
@nhozdien Indeed, James Bruton has had a number of failures where the motors in his robots are directly attached to 3D printed PLA brackets through the PLA softening.
This may have been mentioned already, but it would also be great to see results from an injection moulded or machined plastic gear - to see how much impact the printing process/settings actually have on the strength.
With every new filament I was left with more & more questions. Not only do I want to see 100% infill, I'm also curious to see what happens if you turn to a different gear with each additional amount of force.
You should use double helical gears. You are printing so you can do the double helix in a single gear. (Kinda looks like a tractor wheel.)this gear type is great for high load applications.
I really like these "real world" tests. When it comes to PLA, there are so many varieties and blends, that I really like the vendors that let you know the base filaments. If you can find some PLA based on NatureWorks 3D870 Ingeo PLA, you'll have a modified PLA that can be anneals very well for extra strength and temperature resistance. I'd also like to see CF-PETG and CF-PC (or an easier to print PC+ Blend).
Nice work! I'd say the PA12 (nylon) is a better choice since it doesn't damage the gear at all when it fails. Meaning you can keep resuming the use of it, long as the load goes back down and stay under. It's like a fail-safe damage prevention. Ideal for any sudden force/stop situation in RC cars.
Angus, the amazing thing about 3d printing gears is being able to make herringbone and double helix gears, they are far more efficient, resistant to torque, and quieter. For your requirements I would definitely look at Polymaker CoPA-CF, quite pricy but definitely worth it, my second favourite is their normal CoPA, but they aren't as rigid.
@Christian They were also lubricated with slugs lol
RCTestflights made a few different style gearboxes for his autonomous solar rovers, much better durability than standard gears.
@Bordpie I agree with the part you are saying on single helixes but double helix and herringbone don't have this downside. Yes herringbone is stronger due to the lack of a gap, but double helix is ideal for when the gear might get dirt or grease stuck in it, since it doesn't build up in a double helix due to the gap but in a herringbone it does.
Helical gears are not as efficient as standard spur gears due to the higher contact load and sliding friction for a given torque, although for most applications the difference is not significant considering the other advantages. Helical gears are stronger though due to the tooth effectively being longer. It would be interesting if he repeated the experiment with helical and herringbone and double helix (slight gap between the helixes) gears to test the strength increase. Herringbone gears are a bit stiffer in the centre where the helixes meet.
Would also be interesting to see the difference between spur, helical, and herringbone gears!
I'd love to see a full video series about the strength of these plastics in rotational strength (like this one), crush resistance (for use in hydraulic presses), shear resistance, and tension strength. I mean, if you don't do it I will, but you're actually skilled at this stuff.
One of the things I heard from one of the Voron devs is that white filament has a lot of TiO2 in it which weakens it. This might be something to consider for the White PLA ST test or maybe for a future video.
Very interesting results. It looks like it reflects a measure of accumulated material stress, as every torque step increases the material damage level also.
You might see how each material wears as well. I know nylon is known as being self lubricating and slides against other gears well. I printed a couple large gears in bridge nylon for and R2D2 that weighed 50+ pounds and they held up incredibly well. Printing in nylon was a real pain though due to warping and shrinkage
PLA was used for gears and linear slides on hobby 3d pritners because it powderizes as it wears, effectively becoming a dry lube for itself. I've actually been thinking of using it as a linear slide on aluminum extrusions (8020 sells these made from POM) for a project I have in mind where linear rails would be overkill.
One of the most important things on a gear is that it's designed correctly. If you do it with the correct tooth profile for a gear (and correct distance for meshing), they don't slide at all, they just roll. That reduces a lot the wear on gears. Now it does make sense to lubricate them anyway, specially the shaft and sides as those will be sliding over something.
@Aidan Gillett Nylon in and of itself is not self-lubricating, but there are some grades of it that you can buy as bar stock which have been oil-impregnated. These are intended for use as bushings / plain bearings or for sliding contact surfaces. I don't think you could make those into filament, though- the oil content would most likely cause some fairly important problems when heated.
I wouldn't call Nylon self-lubricating, its partly flexible which helps. eSun PLA+ I would call self lubricating as it literally leaves a slight oily film if you rub it with your fingers
Yes, and so any of the filaments cause nozzle wear in your printer? That concern, along with needing to run at higher temperatures and fewer color choices are what keep me away from filaments more exotic than PLA and PETG.
I would love to see the tests with 100% infill, but in two ways. I saw the perimeters separating from the infill. So i'd love a test with 3 perimeters and 100% infill, but also a test were its lets say 100 perimeters with 100%, so that basically the whole thing is a perimeter that doesn't get to cool down and then have a string from the infill just touching it briefly... or heck. Even a test with 1 or even 0 perimeters and just solid infill.
exactly this - the failure points are visible - they're the always infill bond to perimeters. Gears in this scenario are not hollow. This oversight is super weird. Any metal gear with an internal structure like the test prints would be considered defective
I think some have tested that more than 50% infill does not provide any significant increase in strength.
I recently printed a PETG spindle holder. It straight up snapped in two while I was deburring it and removing supports.
Reprinted the part in a different orientation so the layers ran the length of the part, made it stronger, but then it snapped when I tightened it.
Then I printed it in that length orientation, with 100% perimeters and the same part was unbreakable by hand.
And then I reprinted a second one with 100% infill but at 250C instead of 230. It was already far stronger and although I did break it by hand, it was with more force than a spool hanging from it could ever put on it.
For these mechanical parts, layer adhesion is a huge factor, which you can get in a variety of ways while printing.
But post treatment of the parts with annealing or remelting is the easiest and real key to getting them very strong.
Or tighter infill, there is alot of air in his gear, also extra layers between the infill would strenghten.
Very interesting. I would have expected the nylon to be quite a bit better than PLA.
I'd really like to see some kind of wear test on the various gears.
Perhaps set them up skewed or poorly meshed to a driven steel gear and see which lasts the longest before chopping out. Next video Angus? 😊
I print almost all ABS and Esun makes the best I've tried. I'd love to see a POM material tested for gears since it's kind of the go to for injection molded or even machined plastic gears.
Very interesting results, I would have expected a wider range of failure strengths. Is there an .stl available for this gear? I'd like to try out some of the engineering-grade filaments we have at work. We often use Essentium's HTN-CF25 in place of machined aluminum, it'd be really interesting to see how it does.
The 'mechanical fuse' concept is an interesting one. As seen in the comments, there are many instances of them. But one that comes to mind, are called shear pins and often used in lawn and garden equipment, they connect something like an auger to a shaft and will shear if you hit a rock, etc.
I think you should try wear resistance too! :D Like... spinning 2 meshed gears at max rpm for a period of time
In my experience, the best gears are made from Polymaker Polymide and hardened for 2 hourse at 80C. Also, finer teeth tend to be stronger.
I also would fill the gearbox housing with a mixture of mineraloil (babyoil) and vaseline, that reduces friction and cools the teeth, otherwise PLA gears bind up really fast.
Larger teeth are stronger, but not as smooth. Yeah, heat (and UV) kills PLA! Nylon can absorb water. Lube is good!
would be interesting to see how the infill might affect your tests. It looks like some times the infill allowed for deformation which lead to failure. Also wonder how resin gears would fair
Late to the party but if you ever plan on doing similar teasing in the future (speaking specifically to gathering torque data) I'd recommend a torque wrench adapter than a regular torque wrench. You can just keep cranking on it till the part fails and the digital adapter will tell you the peak torque. I first learned about using this method from ProjectFarm who does this in his videos when testing torque numbers. You can get an idea of what I'm describing if you check out his video on Anti Seize compounds, around the 4:30 mark! Or, really, most of his videos on small tools and such but that was the first one that came to mind
yes, the temperature resistance should be something you'd want to look into next, that'll really make a difference when the gears are continuously running.
Glad you got you hands on BASFs Pro1 filament, I've pumped through dozens of kgs of it for fixtures/tooling for my work. It is also advertised as being able to print at a blazing 150 mm/s, but not something I've had success achieving (maybe with a voron build it would be.) Great video!
Just want to say that I'm really enjoying your presentations and demonstrations. Excellent and engaging dialogue and cut-away work.
would love to see you try the engineering grade PLAs like the anneallable ones, Formfutura Volcano PLA etc
I replaced all the gears on my old craftsman 6 inch lathe with 3d printed gears made out of Taulman Alloy 910. Been using it on and off for years now. Works great. Plus it has two added benefits: 1st, they are self lubricating, so no need to oil them, and 2nd, they are much much quieter.
Could be interesting if you updated construction of each gear according to most probable break line
Great video. One point that is missing though is friction. For low speed, it probably doesn’t matter but i think nylon will perform much better than most in this regard. I would love to see them tested at a few different speeds meshing to see which fails first. Might be time consuming experiment though.
I was hoping you would try carbon fiber nylon and very happy you used PCTG. I like PCTG (from Essentium) and thanks to this video I know why the stringing starts to happen. I've got a drier so I have the solution.
I have been using eSun Filaments for some time now and I do like the results. I have printed some puzzles and toys with eSilk PLA and the finish is great. Thanks for your videos Angus. PS I have a Prusa MK3S.
Before watching the video I'm going to go ahead and say that my personal favorite is PETG. I'm very curious to see what your results are!! Update: Okay, how could I have been so wrong haha. However, to note, the quality depends so much on producer that I think it's impossible to say which material is the worst.
I have been designing some machines lately and the PETG that I used for the parts worked better than any other material I tried to print with. I've never had a failed part with this PETG I'm printing with, and it's lasting much longer than any other PLA I've printed with. Most PLA's would start to crack after one year of use. They say that PETG has worse UV resistance, but I think that in the end the PETG I have holds up better than the PLA I had.
On top of that this PETG prints really nice with an E3D hotend with a titanium filament path, so no PTFE tube inside this hotend. I was expecting problems, but my prints never looked this good.
One more thing I miss in the comparison is a comparison of the friction coefficient, which greatly impacts how long a gear survives, and how hard it is to turn. Some plastics just really aren't that frictionless. PLA in my experience performs the best as a common filament, but Nylon should have an even lower friction. And eventually PTFE has the best of all of these, but I sincerely recommend against using PTFE in a 3D printer as it's a super dangerous plastic. If you have pet birds, stay away from printing with PTFE as your birds will definitely pass away from even the tiniest amount of fumes.
I don't think you're wrong, PETG would still be my choice under the circumstances. I had some loaded PLA prints and there's some chemical degradation happening, they all shattered after 1-3 years, it doesn't even feel the same. PETG is pretty well behaved, low surface friction, good abrasion resistance. UV resistance? Depends on additives and colour, but i wouldn't say PLA is anyhow remarkably good in this regard, not from the tests i have seen.
Nylon could be worthwhile, maybe HIPS, SAN, ASA, worth testing, but PETG is so cheap and doesn't cause much headache...
I'd be interested to set the fatigue properties of 3d printed gears. A lot of these gears flexed back and forth, and that likely causes premature failure much earlier than these tests would indicate.
It would be interesting to test annealed pla (of course compensating for annealing deformation)
A wear test would also be nice. But a lot more difficult, depends on speed, load, heat.
So, another potential testing setup (that will probably not result in different results for the torque but might for failure mode) is holding the printed gear static and driving the metal one (which would closer simulate the gear being driven instead of the gear driving). Also, I'm very interested in the fact that most of the PLA failures seem to have been from two parallel perimeters coming apart. I wonder what might change if the base was slightly different, perhaps seeing a variety of gear diameters, which might be useful to know if you need gear ratios.
Nice set of tests. I am looking at a number of printed gear applications in robotics. Three things worth mentioning. (1) Infill - as many said, a sold gear would be interesting to try. (2) But I think the clearance on the hex is also important for those where the hex rotated. The clearance might seem an insignificant figure when compared with the A/F dimension but, in reality, the clearance should be compared with the difference between the A/F and A/C. This is a much bigger percentage. We drive a lot of 3D printed mechanisms with 1/2" hex rod and always ensure the fit on the hex is as close as possible. (3) It's probably also worth extending the length of the hex socket on the printed gear and perhaps making it thicker to ensure it is not the first point of failure. Then we can see what the teeth will really do with the Nylons. Great work and I always enjoy your clear and concise delivery - one of the best!
Great testing. One thing instead of a torque wrench, a ratchet adapter with torque readout might have been better
It would also be interesting to test different types of gears like helical and herringbone ones
Would be interesting to perform same tests on 45 degrees printed gears.
Just for reference, BASF (an acronym of "Badische Anilin- und SodaFabrik") is one of Germany's largest chemical producers. I didn't know they made 3D printing filament, but honestly I shouldn't be surprised xD
Absolutely love this comparison, and if I could add a suggestion: when you do the "100% infill" comparisons, I think it might be interesting to know whether the infill pattern (specifically "lines/zig-zag" versus "concentric/spiral") makes a difference, especially since this experiment is focused on rotational strain.
Great video! I wonder if herringbone / double helix gears would handle more torque with the stronger filaments you tested. Any particular benefit to using a spur gear instead?
Awesome, I'd print them individually instead of simultaneously just to see if it's any better
Amazing work
The ST play is super tough. Toughness is an engineering term where it will deform before fracture. The tougher it is the more deformation before fracture
This was super cool, dude! I'd be curious to see what a chopped carbon PLA would do, if you try this again.
Thanks for the very interesting video. I've impressed with CF PLA and CF PETG stiffness, but I'm not sure how a CF filled gear would wear. The surface of CF parts seems fairly abrasive. Maybe a slippery surface is more important than outright stiffness for gears.
Nylon is often used for plastic gears, I think because of reduced friction, not for increased strength. That said, good PLA is a huge improvement over what it was like in the early days of home 3d printing. I could actually crush in my hands the parts delivered for my old threaded rod Prusa printer, it reminded me of pasta. The new high quality PLA is much improved, and hasn't caused me problems yet. I think if I were trying to protect an expensive motor, I would add a part designed to break first, probably attached at the motor shaft, say a coupler with a groove of smaller diameter to be an intentional weak area with an experimentally determined size.
I've been using "generic" wanhao PLA to print change gears for my metal lathe, an old Southbend Clone, and they've been able to take some pretty heavy cuts with no failures yet. I agree that a sudden shearing or stripping of the teeth is definitely preferable so I like the brittleness of PLA for gears. Rather have them let go all at once and get out the way
PLA is very much underrated!
Tough or strong filaments usually only means more impact resistance and less stiffness.
Buddy of mine sent me a hard-to-find drive gear from his Wurlitzer jukebox. I measured and modeled it in Fusion 360 and printed him 6 sets in Nylon on a nearly stock Ender 3. Two years later, and he's still on the first gear.
I love 3D printing.
I would love to see a dual material print with the best performing rigid material and best performing material with higher flexibly!
I'd like to see the tests performed again for Nylon or anything else that fails with a hex drive. But do it with a different drive, like a cross pin or other similar mechanism that won't fail to simple minor flex.
Nice video. With the way the teeth failed along the perimeters vs infill, I would like to see you do some of this testing with more top and bottom layers and a larger overlap into the perimeters. ALso would be interesting to see if actually less perimeters and denser infill so there is more of a connection to the mass of the gear at the point of repeated failure (the base of the tooth).
I would be interested in seeing results from something like Prusament PC Blend in your test. This stuff is strong as hell.
Would like to see a spin test between each torque setting, since even if the gear doesn't "fail", it could be deformed enough to not mesh properly anymore.
For PLA lubrication would be nice. That lowers the heat generated due to friction thus allowing for a hotter enviroment before the gears melt.
Well I was very surprised, I was expecting nylon to be the best! Great to see many other materials tested.
You could also try to get a range of the expected torque transmitted per application of those gears, i.e whether it's used to drive a fan or drive an industrial shredder, and everything in between
I think PETG salt annealed gears would be really cool to test since they might actually work
Materials engineer here. "Tough" and "strong" mean different things. Tough materials are able to withstand damage... which is why they tend to be a bit soft. I bet the ST PLA is really great for impact resistance while other generic PLAs can be rather brittle! Your gear test was evaluating strength!
Results of Polycarbonate (PC) would be interesting too. Teeth and area of contact of the teeth to the radius of the gear should be printed with 100% infill and the center with infill, therefore the teeth have more absolute strength but can bend relative to the center of the gear . That avoids too brittle breakage behavior. Additionally, the infill can be designed to correspond to the inner stress introduced into the radius (But therefore has to be manually constructed in the CAD itself and not to be used with the automatic function of the slicer software) Cubic infill f.e. is not suitable because the stress is mainly "in plain" , and therefore the 3-D part of the infill does not have any beneficial effect to the strength of the structure.
i had a BASF ABS and man this was amazing this filament. no warp on a open 3d printer.
I'd be curious of the results if you were to 3d print a mould directly and cast them in resin what they'd be like. Could them compare adding in different fibres (glass, carbon, flax etc).
Yeah it's a 2 step process but could unlock a whole new level?
I've been very impressed with PLA. I had PLA rack mounts for my trucks roofrack. They deformed, but held up to some serious offroad abuse for nearly a year before they deformed too much to hold the rack in place.
I would really love to see some ABS blends like fiberlogys ABS plus, Esuns ABS plus or 3DJakes niceABS. And I would really appreciate if those materials were printed in a heated chamber, even if the manufacturer states they "can" be printed without one, because based on my own testing layer adhesion without one is really terrible, even if the print doesn't outright warp.
I'm surprised that you didn't think nylon was the best gear option because of the failure mode. To me slipping without long-lasting damage seems like the best way to protect everything else. Presumably with a bit of experimentation, it'd be possible to design at what torque the slippage would happen as well.
Nice video 🙏. BASF ultrafuse used to be innofill until they where aquired by BASF. We print solely ultrafuse PLA and ABS and the properties are indeed very good.
The only thing I wonder is, does age influence the strength? I mean, it printed nice, but that is not necessarily the same thing. Did you test anything that is not +5 years old?
Hey Angus, super curious if you had the chance to test Poly Carbonate? From what I know that would have been the ideal material in terms of rigidity and temperature resistance.
Very nice video and great data. I would love to see the highest ranked with a solid infill and see how those stand up to the torture. Also like to see similar video with the other filiments you have on the way.
As for drivetrain failure. I did some RC short course racing and learned alot about different ways things break. Lol like for the steering servos for example. There was a common upgrade called a servo saver. It was basically a spring inside a 2 piece housing and the spring would take the abuse so the servo didn't. I learned in the steering system and the drive train there are always going to be at least 1 part meant to fail in order to reduce the chance of other things breaking. The spur gear that was attached to the gearbox and meshed with the pinion gear on the high speed motors. Those were designed to fail. There was also a tension clutch on some that had 2 disks squeeze the spur gear with a abrasive ring of what felt like grip tape. The clutch tension would save the spur from taking those jolts from high impact and the spur would shear off teeth if the motor continued to spin.
For your application I would say use a material that shears off teeth for your bigger gear at roughly 75-90% max torture of the motors depending on the safety margin you are going for. For the gear on your motor I would think an aluminum gear would be better.
Does the positional orientation of the hex hub versus the tooth engaged with the stationary one have any effect on gear failure? Would be interesting to model the gear with the 3 outer perimeters and infill and perfrom a FEA analysis to see if orientation has an adverse effect. Still, a very good set of tests.
I think it would've been better to use a dial or beam type torque wrench that would record the max torque you hit for these tests so they could be done in a single load cycle.
I’d like to see CPE filament tested. Also does the age of the filament make a difference to its strength?
This brought to mind an idea. Could you possibly print with metal (washers) imbedded in the material for added strength, perhaps allowing you to control how the gear fails.
that would actually make it weaker unless you make a way for the plastic to grip on to the metal.
Hello! I'll throw in an idea: a gear wear test. You fasten a series of gears in pairs and through the drive you make them spin for a certain time. And then measure their size. It will be interesting to see. PS: I also want to say that the video is gorgeous. Thank you! (:
surprised you did not do 100% fill, would be interested to see those results, great vids! cheers
It seems that PLA would have worked much better with thicker wall thickness. It seems that you mentioned later that you would test with solid gears but I think you should try different wall thicknesses, too.
Considering that BASH Pro PLA seemed to be the best you could try different wall thickess tests / solid gears only with that to get idea how much that matters.