Curing Tips and Tricks

General Discussion
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Hi - I’m Jonathan, a Product Manager at Formlabs. One thing we’re always on the lookout for ways to improve my post-processing, especially when it comes to curing.

What are some of your go-to tips or tricks for achieving a great cure? Do you have any preferred methods or settings that consistently give you top-notch results? I’d love to hear what works best for you, whether it’s about timing, UV exposure, jigs/fixtures, or any other factors you’ve found important.

Happy printing!

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Indeed I do have some thoughts and way more experience than I should regarding this. I would encourage you to start with this thread: My experience with the Form 4(B) so far/ Semi-Review from a Semi-Industrial User Perspective - #8 by eaglechen Pay especial attention to my comment at the #8 position and my comments about medium term improvements I think are necessary, in reality this is applicable to the entire Formlabs SLA line and not just Form 4. I would also encourage you to read the entire thread.

I think the fact that you are here asking us how to best achieve curing with your products and whether we have any black magic tricks beyond Formlab’s own guidelines is very telling… I think testing of curing and how to actually get a good accurate final part in hand is unfortunately minimal from Formlabs. Unfortunately, I do not believe any tuning, UV exposing, and building fixtures no one ultimately have the time for will be helpful; I think a fundamental overhaul of this process or some serious engineering and testing is necessary. This will at least involve a cure redesign and possibly material changes in the future. If you want to sell your printers as an “industrial system” this process NEEDS to be better controlled and this work should have already be done ahead of time by Formlabs for the price of your curing systems. Of course, it feels really bad to throw away a perfectly good looking green part off the printer that failed to cure, I have certainly wasted a lot of time and money over this.

I will give you a brief summary: essentially, the Formlabs post-processing process, especially curing, currently SIGNIFICANTLY lacks behind competition in the industrial realm. This process is so inconsistent, it’s much more artistic and seemingly random than even baking a cake. I frequently have to print, reorient, and reprint just to get a usable part. I have had significant trouble getting engineering materials to cure reliably without warping on Form 4, and I basically tell people to avoid the 3L because getting anything to cure with a semblance of accuracy is pretty much impossible. Curing is anything but the “easily cure after the print, if you like” that Formlabs advertises.

Also do keep in mind the wash + cure + basic sanding of supports is already far longer than it is to print an average part on the Form 4.

Some root causes leading to common pain points that I am sure everyone has experienced:

  1. The curing temperature required for especially engineering materials (any tough or rigid 4000) is significantly higher than the heat deflection temperature of green materials; even general purpose materials suffer from this issue. Basically, this means that green parts will collapse under their own weight, bend, or even cause the support structure to collapse under the weight and warp the part from the material softening before the LEDs turn on. This is a significant issue on Form 4, and an even larger one on Form 3L.
  2. Due to the issue above, curing after support removal without warping is pretty much impossible, especially with engineering materials. I have resorted to further anchoring down parts with dense supports and orienting some large flat things that can probably be printed directly on platform upwards to try to get a successful cure.
  3. Because tough materials are tough, and durable is durable, a successful post-cure means that often the supports become welded on the part and removal is impossible. Feel really, really bad when I finally have almost the product in hand and i break the part trying to take it off supports.

Some ways I would go about solving this:

  1. I think base Cure and CureL needs redesign (perfect opportunity as most things no longer fit in Cure from Form 4). I would encourage a system like: https://support.3dsystems.com/s/article/figure-4-modular-figure-4-uv-curing-unit-350?language=en_US allowing you to hand the part straight off the build plate during cure like Form wash. The support materials are designed for tension forces, this along with the part attached to the build plate probably can pull the part together into a better cure.
  2. Current support touch point size and removal sucks. Curing then remove support is very far removed from a “light touch” experience. I am tearing chunks of the part off instead of the support points often. I think Form 4 has a long way to go and is capable of huge support material optimizations.
  3. I think Formlabs needs to move towards the direction of investigating if strong LED with much higher energy intensity can be substituted for high temperature. For example, would it be possible to cure like tough 1500 at ambient just with strong LED blasting and no heat? I am not a material scientist, but this obviously would eliminate the huge pain point of parts warping in the cure. The Fast Cure exists as a product (which does not use heat from what I understand) so there may be more credit to this idea.

All of your competitors in industrial DLP are moving towards open or semi-open systems with validated setting for like the Loctite or BASF line of photopolymers. Those resins are price and performance competitive (sometimes a lot better) than the Formlabs engineering materials. ALL of them utilize a room temperature curing process or curing below the heat deflection temp of the green material, Allowing for easy support removal before curing and reliable cure performance. Large top down SLA machines have utilized this process of just UV baking the part with no active heating and allowing very large and heavy parts to cure accurately for years. I believe Formlabs has some serious catching up to do in this regard as well and the next generation of Formlabs materials NEED to do this to remain competitive.

edit: Basically all the issues I described above are hugely amplified on 3L due to larger part sizes. I believe Formlabs needs to do some serious homework and rethink this process if the 4L (if that ever exists) to be a usable printer.

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Thanks for the note @eaglechen. I appreciated your detailed feedback in the other thread and here; as you know, we’re continuously working on product improvements which includes addressing the things you brought up. Our goal here is to make sure aren’t blind to alternative curing approaches our customers are taking, as we want to make sure our products support the many different goals of the printing, washing, and curing process.

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