Has anyone any tips about reducing the ‘elephant’s foot’ when printing on the build platform?
I’m using Tough 2000 on a Form 3.
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Good morning, @billb -
Thank you for reaching out about your prints on the build platform. The flaring at the bottom of a print directly on the build platform is normal due to the laser power needed to get a print to adhere to the build platform.
That said, our Advanced Settings in Preform has an option to adjust the z-compression on a model. This can reduce the early layer flaring but reducing it too much can introduce issues with adherence.
Regards,
-Jen
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Thanks for your input. However, I was hoping for some practical experience. I know about and use the z-compression setting, but note that while I get a ‘flange’ up to 1 mm wide, the same thing on the T2000 sample is less than 0.1 mm. Is this due to some magic internal Formlabs setting, or is it something that us ordinary folk can achieve?
Best way is to account for it in your models, but beware (I learnt this the hard way) it changes depending on resin and even layer height.
Also you have an elevated risk for prints to detach and convert your resin tank into bowl of half cured resin flakes which are NOT fun to clean up.
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The only way I’ve managed to reduce the “flange” was to make a correction in the CAD model, and even then it did not completely solve the issue
Indeed… not fun, also Cleaning Mesh is not supported with Tough2K or Durable
I do a lot of my printing direct-on-base and am passionate about eliminating the flaring aka “elephant’s foot”. I wrote about the topic here (and if you click the first link in that post it takes you to a diagram illustrating the effect).
Tweaking the Z-tuning as Jennifer described (raising the build platform up until it’s “just low enough” for your print to stick) can definitely help. I’ve done extensive tuning on my Form 2 and substantially reduced (but not completely eliminated) the flaring.
Haven’t played with that knob yet on my Form 3. It was only introduced for that printer in a more recent firmware, but really glad to see it there.
If you want to get more exotic… one user applied a black coating onto the surface of his build platform and reported it completely eliminated the problem (presumably by reducing reflections):
There’s also a good suggestion in that thread which Formlabs could explore to improve the situation via software, eg:
Instead of applying the burn-in layer to the entire perimeter, PreForm could offset the perimeter of the first layer inside about 0.3 to 0.5 mm for the primary burn-in time … and then apply less laser power/time to the true perimeter
@Jennifer_K Has that suggestion ever been raised with your engineers?
@Terry_Miller I’d love to buy a coated build platform from you to play with if you ever decide to sell 'em!
Finally, I think I read somewhere the Form 3+ (note the “plus”) tweaked the laser power of the initial layers to also help reduce it. I’d love to hear from a Form 3+ user who’s printing directly on the build platform as to whether that’s true and they notice a difference compared to earlier models.
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Hello @rkagerer -
Thanks for the suggestion; I don’t know if something like that has been offered as feedback so I’ll put that in as user feedback on prints on the build platform.
Regards, Jen
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The issue of defects at the base of a part has been the single most disappointing thing about the Form 3 platform for me. Some resins like Rigid 4K and Draft print beautifully with no defects on the base layer. Standard resins, however, appear to expand the first layer or two by a millimeter or more with a thin and uneven layer of material that cannot be mitigated by software settings or adjustments to the CAD model:
As @rkagerer mentioned, I did experiments with different PET films (even Kapton tape works) and powder coatings. I hypothesize that these reduced the problem by either reducing reflections and/or absorbing some of the laser energy. These experiments were done prior to the new flexible build platforms and they suffered from poor durability, so I discontinued their use. Prior to the flexible build platforms, I made my own flexible platform with very thin magnetic material and then ultra-thin shim stock. Not nearly as good as the new Formlabs ones, but it worked relatively well. Now, I am using Formlabs’ flexible build platforms.
@Jennifer_K, we really need a way to fine-tune the power settings for the first layer. Also, your explanation of Z-compression adjustments doesn’t really make sense to me. My understanding based on using Preform and reading the description on Formlabs’ help page is that it simply works to expand the z-height of the model. On a Form 3 machine, it does not affect how far the build plate is from the normal starting position during first-layer printing, which is what I understood from reading your reply. The help page linked above even goes on to advise against adjusting this setting on LFS printers (like the Form 3), explaining that it will negatively affect dimensional accuracy.
Here is a standard model on the left, and one with 3 mm of Z-Compression Correction on the right. As you can see, it appears to just extend the model’s first layer by 3 mm.
Maybe with the Form 2 or earlier there was an option to offset the distance from the build platform for the first layer, but that does not appear to be the case with the Form 3. Am I mistaken? Is this confusion the reason why this issue is still apparent years later?
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Hi @Terry_Miller,
There is now an option to offset the build platform height with Form 3 printers as well - see Fine Tuning Formlabs LFS printers. As you noted, this option is different from the Z-Compression Correction setting in PreForm, which adds height to the base of models as you described. I’ll also pass along your feedback regarding being able to control laser power settings for early print layers.
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