Additional Resin Layers on Bottom side of print (opposite supported side)

Form 3, Clear Resin v4, 50 um print height, IPA bath for 20+ mins.

Sometimes I get what looks like ‘pooling’ (for want of a better word) on flat, horizontal surfaces on the bottom of a print- the opposite side to the supports. It sometimes creates a smooth, very transparent finish, like the resin has been painted on and cured (photo 1). On some parts, it will clog up fine features on the bottom of parts, or collect in corners (photo 2). Usually I can scrape off limited build ups before I post cure it, but the end result looks pretty bad. It’s very inconsistent on the part itself and between days. Mostly I don’t get this at all.

With angled surfaces this generally doesn’t happen, but I can’t always do this because of other important dimensions on the part.

Any ideas what could be causing this, and ways of mitigating it, other than changing the orientation of the part?


Hello @kiben17 -

Thank you for the question you have on clear resin. The challenge here is minimizing laser bleed. Clear resin, well, is clear - it stops the laser less from curing around later layers on a part.

The Support team may be able to help in more detail with this part, as well.

Kind regards,

Thanks @Jennifer_K ! I remade the part in white resin and did not have the same issue.

For projects where I need to use clear resin, do you have any advice for minimising the laser bleed that you mentioned? Things I wondered about were:

  • position on the platform bed
  • number of parts on the platform
  • different heights of parts on the platform
  • ambient temperature swings
  • layer thickness (which layer thickness minimises laser bleed?)
  • would mixing the resin more between Z steps help?

The photos I posted previously were from a crowded printer platform, lots of different parts. The parts on the mixer side of the platform had less of an issue than parts on the opposite side of the platform, but that might just be coincidence.

I wondered whether making a little ‘laser shield’ ring around sensitive parts would help? Like an extra surrounding part that blocks out laser light from other parts.

That extra layer sometimes looks really good on parts where I don’t care about dimensions but want it as transparent as possible. Would be grand if that was a print option. You can have that idea for free :slight_smile:

Good morning, @kiben17

Looking at how we reduce skirting and laser bleed on Clear parts, there’s two major things.

Lower layer heights will reduce the amount of bleed just because there’s less resin to be cured.
Orientation is very important - the laser bleeds in the xy plane on all prints but bleeds in the z-axis on Clear resin, as well. Orienting it so that the parts that you don’t want to have the little bit of extra cured resin oriented downwards can help, but you have to be aware of where your supports are, as well, so you don’t complicate finishing.

Kind regards,

is there a good example video for this particular resin and its difficulties?
It would be great to have videos for each of the resins. and to know some of their special requirements and issues a customer can encounter. …

Hi @illuminatedRS,

We do have a Guide to Transparent 3D Printing covering some processes for printing with clear resins. With that said, it doesn’t necessarily cover this particular issue. This type of laser bleed with clear resins is a fairly niche limitation affecting small, detailed parts. We generally address this on a case-by-case basis to see how parts can be adjusted to minimize this effect.

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