Hi, I’ve started printing with 4N alumina on a Form 4 and I’m having problems with inconsistent adhesion to the build plate. Sometimes the print peels off “easily”, other times it’s impossible to remove it without destroying it. I suspect it’s due to the roughness of the build plate. It’s an almost new Flex Platform, but it does have a few scratches. I’d like a reproducible process. Is there a way to coat the build plate? Would glass bead blasting help? Or should I smooth the build plate, for example, by polishing it? The parts either seemed to be stuck way too strongly, extremely so, or couldn’t be removed without damaging them. We were miles away from normal adhesion, let alone the possibility of the parts detaching on their own, in all our attempts.
Another issue is creating support structures. With every parameter I’ve tried, it’s impossible to create practical structures for this material. Would it be possible to build more flexibility into the software here? Manually drawing the support structures for each part is very tedious.
Thanks for posting! It looks like you are asking about prints not adhering to the build platform. As a first step, we recommend checking out this Formlabs support article: Diagnosing a print failure (SLA) | Formlabs
Once your issue is resolved, please mark the topic as Solved.
Sometimes I have trouble with adhesion on things towards the front or back of the flex build plate, where parts placed more in the middle have no issues
You may have better luck with the non-flex plate, which is a lot smoother. But you may have to rely on chamfering in that case
Thanks for the info. I’ve already noticed that the parts in the middle didn’t adhere as well. I’ll get the regular build plate to try it out. The release mechanism of the flexible build plate doesn’t work with the N4 at all.
Is there anyone here who has experience with the N4?
No experience with alumina but a few things you could try based on a lot of experience with other resins.
Redo your build plate alignment. It might be making adhesion high in some areas and less in others.
Do z fine tuning and increase the distance to the bottom of the tank to make adhesion less
Lower the first layer exposure values in the print settings
Purposely wipe some oil on your build plate to make adhesion worse (not really recommended but I’ve done the opposite of using acetone to wipe and clean contaminants off when adhesion was bad and it would reset adhesion back to good levels)
Hi @TobiOneKenobi, the system reply came from our keyword-based auto-responder - and you’re right that it completely missed the mark here! We’re looking into improving its functionality and have turned it off for now. Thanks for flagging!
As for your question: We also recommend aligning the build platform as a first step like @leonhart88 has suggested.
Regarding the supports, please make sure you follow the specific Design Guidelines for Alumina 4N Resin. These recommend 0.4–0.8 mm touchpoints, with 0.5 mm preferred, avoiding touchpoints on critical surfaces, and orienting parts to be as self-supporting as possible. Where supports are required, it’s recommended to orient the model parallel to the build platform.
Because Alumina 4N has specific ceramic-processing requirements, some manual support adjustment may still be necessary for complex geometries. The Alumina 4N Quick Start Guide also provides an overview of the recommended workflow.
I hope this helps - if you keep encountering issues, please don’t hesitate to reach out to our Support team.
I have no problem with the support, and the overhangs work perfectly. I also have no problems with the orientation. Everything works great. Only the adhesion to the build plate is way way way too strong. I have an explanation for this. Every time I clean the build plate, I’m sanding the stainless steel surface with the aluminum oxide powder. This results in a freshly sanded surface each time. I tried coating the surface with silicone once, and that helped. Unfortunately, I can’t do that because of my process. Do you have any recommendations for what I could try? Or have you tried anything like this before?
It seems to me that the software/the whole package isn’t really designed for this material. Every time I start a print, the mixer detects debris. If I stir it manually a few times, the print starts. Could you add the “stir a few times” function as a default before starting a print?
Would it be possible to enable scaling depending on the axis? That would be very practical for 4N.
Generally, strong adhesion between Alumina 4N parts/rafts and the build platform is a known behavior. Currently, we don’t have a validated recommendation for reducing adhesion by modifying or coating the build platform surface. Please note that while reducing adhesion could make part removal easier, it could also increase the risk of the print detaching during the print.
For this reason, our current guidance focuses on safely removing strongly adhered rafts rather than reducing their adhesion - please refer to the Rafts strongly adhered to build platform section of our Alumina 4N troubleshooting guide. Media blasting the platform surface (as suggested above) is an option that’s only recommended when using the Stainless Steel Build Platform.
Regarding the debris detection error, I’m afraid there is currently no option to have the mixer simply stir the resin before starting a print. If you start a print after the resin has been sitting in the tank for a while, manually mixing the resin with a non-marring tool is a good practice - please check the section “Particulate setting in the resin tank” in the Alumina 4N guide for more details.
Axis-specific scaling is currently not available, but has been requested previously and we’ve let the responsible team know about the demand - thank you for flagging, as this helps us see which feature requests are most popular!
The section only covery "Rafts strongly adhered to build platform" but not “impossible to remove without destruction”. My problem is not addressed in your documents.
From your reply, I gather that you’re no longer working with the material or developing recipes for optimal printing results. Is this material that you’re no longer pursuing?
I’m sorry to hear the general guidelines we shared were not sufficient in your case.
Our team recommends the following additional steps you can try:
decrease the early layer exposure in Print Settings Editor to make the bottom of the part slightly softer
place the build plate in an oven at 60-80°C for a few hours so the part shrinks a bit, which can make removal easier
alternatively, freeze the part to make it stronger, making it less likely to break during removal
Our Material Development team would also love to hop on a quick call with you to look into your specific results with the material. Let me know if you’d like to be connected with them!
Thank you very much for the info! Would be great to talk to your material development team. I already optimized the sinter procedure and I will do TGA sinter optimization soon too. Maybe after the test I have new data to discuss this topic too.