Hello everyone!
I want to print a huge gear set of about 240mm of diameter with a module of 5 (big teeth) on Form 3L. Load is negligible in this application but it would go at 160 RPM. I would rater not go in metal to avoid needing an oil pan.
The flimsiness of the Durable scares me while I’m questioning the wear of the Though 2000 in long terme use. And yes planning to use Super lube, thanks to this wonderful community.
There is a post on this from 2017 but I’m curious to see if someone has newer experience or advice.
Thanks for your time!
Durable, as the name suggests, is indeed incredibly durable. Not knowing how your gears are designed, the key with durable is wall thickness. Thin walls will be ‘flimsy’, which is great if you’re looking for parts with living hinges. If you want parts to be rigid, increase wall thickness. Or better yet, make the part solid. Wall thickness 5mm or greater will be fairly rigid.
Tough 2000 is definitely very rigid (though not as rigid as tough 1500). It performs more like ABS or Nylon more than Tough 1500. Being more rigid, you will need to add radii to all hard edges else they will chip.
Dimensionally, Tough 2000 is more stable than Durable, which tends to swell a little. In both cases, the wash is very, very important. Use fresh 99% IPA.
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Durable is great for gears or parts that need to repeatedly interface with itself since it’s self-lubricating. I’ve found that you lose a bit of surface detail and thinner parts are more difficult to print because it’s slightly softer than Tough 2000, but it works great for chunky parts, like @SteamFactoryLLC mentioned. Tough 2000 should also get the job done, but for the self lubricating properties, I would personally choose Durable.
*Slight correction to @SteamFactoryLLC’s message—Rigidity typically refers to the stiffness of a material, which is directly related to its tensile modulus. The “2000” and “1500” are the tensile moduli, so Tough 2000 is more rigid than Tough 1500. The higher the tensile modulus, the stiffer or more rigid the material is. If we were to describe Durable Resin with the same naming convention of Tough 2000 and Tough 1500, it would be called something like Tough 1000, if that makes sense. Hope this clears things up.
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thanks for clarifying.
It’s interesting, however, as we have seen that 1500 “feels” stiffer than 2000. Or, perhaps stiffness is not the right word to use. For instance, ABS does not “feel” as stiff as PLA. Consequently, ABS is more forgiving (compliant) than PLA. ABS has a much higher tensile modulus than PLA. A higher tensile modulus just means it can take more elongation than a lower tensile modulus. Elastic modulus is a better measure of stiffness.
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also, regarding detail and thinner parts in durable, the latest Durable material on the Form 4 prints parts with thin walls and detail much, much better than Form 3. We have a part we print for a customer that takes advantage of this to create parts with living hinges. Durable is great for this. The biggest factor here is to make sure you clean with fresh IPA and use air to dry the parts if there are small cavities.
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Elastic modulus is the broader concept of the amount of stress required to achieve a given amount of deformation within the elastic region of the material. In plastics, we typically measure this in a tension test (called tensile modulus) and in a 3-point bending test (called flexural modulus). We specify the two values because plastics sometimes behave a bit differently under the two different load conditions, but both are measures of elastic modulus.
PLA generally has a higher modulus than ABS, but ABS usually has better impact strength and elongation at break. If you look at Bambu’s property chart, you can see that their PLA has a flexural modulus that is ~1000 MPa higher than that of their ABS filament.
Glad that you’re having success printing thinner features in Durable Resin on Form 4. You’re also totally right about thickness being the biggest factor—the stiffness of a part depends both on the material and the geometry. However, doubling the modulus of the material increases the stiffness by a factor of two, while doubling the thickness increases it by a factor of 8 (for a rectangular cross-section in a beam-bending load case).
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Thank you all for all these advices.
From your experience, It is still worth it to add Super Lub with the Durable resin?
Thanks!
Thanks for the info @efisher. No doubt you guys have spent way more time exploring these properties than I have.
Big picture, I am absolutely astonished at the advancements made in SLA materials. I’m old enough to remember that you didn’t handle SLA parts much after printing else they’d fall apart if you looked at them wrong.
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