Cylindricity of the holes

Support & Troubleshooting Form 3/3+
1

Hello,

When I’m printing (resin High Temp), the holes are perfect circles only if the holes are parallel to the Z axis.
Other wise, the holes are always oval (0,2mm !)
I’m not sure what I’m doing wrong.
It’s not proportionnal to the size, it’s always more or less 0,2 / 0,3 for prints with diameter between 10 and 50.
Any ideas ?

Thank you

2

Good morning @l_roch ,

Thank you for your question on printing channels in parts. This is caused from the laser not being infinitely small - partially cured resin will be in the channel if it isn’t perfectly vertical, and if not cleaned immediately can cause those channels to be slightly oval instead of circular.

I would recommend orienting as close to vertical to minimize the issue, and clean parts immediately or as close as possible immediately with a syringe or squeeze bottle of solvent to get partially cured resin out of the channel.

Kind regards,
Jen

3

Thank you, it was definitively what I was thinking about…
I try to do my best to print parts vertically, but in for this specific part I have surfaces perpendicular to those holes. If I want perfectly round holes, I will have planeity issues on the other surfaces.

Do you know if there is a way to diminue the phenomena ?

  • Printing with a less fine resolution ?
  • Changing to other resins ?
  • I understand that it’s necessary to remove and clean the parts as soon as possible : is it possible to delay the start of a print ? (to avoid finishing the print in the middle of the night)

Thank you

4

Good morning,

Dropping to 25um is certainly an option for resolution. Other resins shouldn’t change much with channels in parts.
If your printer is connected to the Internet, using Automated Printer Readying and Remote Printing can let you send a print to the printer when you need; there’s no way to timer-delay a print but you can set up the printer to print remotely.

Kind regards,
-Jen

5

Our holes, even vertical, are almost always undersized. If possible I usually plan to drill or ream to size.

6

I totally agree,
holes in our prints are almost always slightly oval, so in practice (where hole size is critical) we undersize the hole by approx .25mm and drill or ream to size.
when using Hi-Temp resin I will drill the holes by hand since Hi-Temp is brittle once cured.

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7

Thank you,
Drilling is not always an option since I’m searching for something with a very good accuracy.
In this case, the high temps resin is indeed very brittle, I’m unable to do anything after curing.

The solution I’ve finally choosen is to put the holes perfectcly perpendicular. I’ve changed the design in order to be able to evacuate the excess resin in the horizontal surfaces.
Now at least I understand that it’s not a problem from our printer, it’s a typical behavior of all SLA printer (we have a low cost Creality printer with exactly the same issue).

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