Corner of raft peeling off build platform during print

My latest Form 1+ print started to peel off the build platform in one corner:

This print was done with a fine tuning setting to lower the build platform 0.5mm. Should I be concerned, or is this just a simple matter of ratcheting down the build platform even further to compensate?

In fairness there are a few other factors that could very well be contributing to the issue:

  • The resin is rather aged

    But aside from that corner, the rest of the print seemed to come out reasonably well and didn’t exhibit much pitting (or any pervasive problems throughout the entire print) which I would expect if old resin were the main cause.

  • Old tank

    The tank is only lightly used, and there’s no ghosting. But it is a few years old and I’m wondering if maybe the PDMS has condensed or something in that corner…? Also there are some minor cracks near the top rim of the tank (but nothing lower down and I monitored the whole time to make sure it didn’t leak) - I wonder if that might affect structural integrity and maybe cause the bottom to “bend away” from the platform more than expected?

  • Uneven build platform?

    I have no experience with this and would appreciate someone letting me know if there are tweaks I can do to level things better or push that corner of the build platform out a little further.

    I should note this is the only platform I’ve ever used in that machine and I don’t recall having such a localized issue with it before.

  • Large print

    Maybe I shouldn’t be printing to such a big footprint in one go?

  • Z-Calibration

    I sent this printer in for service some months back and they had to completely replace the Z-Axis worm gear. This is probably the first print I’ve done since then which utilized all areas of the build platform. Is it possible things aren’t quite calibrated optimally? Anything I can adjust “in the field” if that’s the case?

  • MIrror

    I did clean the mirror immediately before printing (and the resin was recently filtered). While cleaning I was saddened to notice some marks on the mirror that wouldn’t buff out. I’m not sure where they came from or when (last time I cleaned it they weren’t there, and I think I’ve barely opened the machine since then). Although I’m quite careful, I suppose I have to admit the possibility that dust marred it (or worse metal shavings or something - I do see those collect toward the bottom of the Z-axis worm gear sometimes).

The base is already getting a bit thin, I’d probably need to thicken it if I move the platform down any further. Going the other direction (raising the platform) I had even worse luck getting prints to stick at all.

I know my next steps are to start eliminating all the things I listed one by one (e.g. try other, newer resins, a different tank, etc.) especially before attempting any adjustments. But I figured I’d check in here first to see if there’s something obvious I missed. Although I might sound dour aside from this corner lift thing I think the printer is performing quite well.

That’s the first thing that popped into my mind when I saw your image. The rafts to look very thin, are you using the standard height ? I would try with the standard height or try to increase the height in preform .5mm higher than default.

They were standard height (2mm). Now that I look more closely it does seem like more than 0.5mm was shaved off; hmm. I measured and the base that came out is around 1mm thick.

I’m not sure but that may be due to the Z tuning, I’m using a Form2 so I can’t help you much more than that unfortunately, I’m sure others or the Formlabs staff will in no time :wink:

How old is this resin? Expired resin can run into issues with curing which would decrease platform adhesion. You may be able to compensate with Z fine tuning and I’d second @JohnHue’s suggestion of thickening up the rafts a bit.

Embarrassingly old :-). I asked it and it told me “Don’t you know it’s impolite to ask a resin her age?”

I thickened my base to the max (3mm) and lowered the BP the rest of the way (to full 1mm). This time it came out looking good and without peeling, although the raft is still definitely a lot thinner than 3mm ;-).

As far as resin goes, age is a bit more than just a number :wink: If this is well over a year old, that could be causing issue here. Glad to hear that you’re able to compensate by experimenting with Z fine tuning and raft thicknesses a bit.

Thanks for the advice, @Frew. I tried a single coin with White v2 resin dated Feb 14, 2016, in a different tray. Nothing stuck even at the lowest Z offset. Oddly in one of the tests the base of the coin was “skewed” across the PDMS (along the direction of the peel operation). i.e. Where I expected an oval shape about 2cm x 3xm, I instead got one about 1.5cm x 5cm. Haven’t seen that one before. It only happened on one of the tests.

I drained the same tray and filled it with brand new White V3 (dated May 22). That one printed fine, even at 0mm offset.

Looks like your intuition about it being a resin issue was spot on.

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.