That is exactly what I would expect from a print orientated vertically like that. It can be improved by either using a lot of very small touchpoints along the edges you want to be sharp or by reorienting the part so that most of the support are on one outer rim. The divots where the supports have removed suggest to me that the touchpoint sizes can be reduced.
Hi @billb, thanks for joining in the discussion.
Just a couple of quick points:
- All of my ring designs print in the same vertical orientation on my Form 2 without problem.
- Increasing the number of touchpoints has no effect on this kind of overcuring, which seems to have been eliminated for other resins through changes to the Preform software and/or firmware updates.
- These touchpoints are the new, super-small ‘light-touch supports’ especially created for Castable Wax resin.
- If you’re interested in the analysis of this problem to-date, take a look at @lmlloyd and @larsenstephen posts on the following thread: Bad prints out of brand New Form 3
I had seen similar issues when printing thin shells with white resin - on the side facing to the build platform is appearing a layer of semi-cured resin which is covering the object small details. I call this issue “parasitic curing of resin” - in the places where the resin can’t flow away and stays for longer in one place, it becomes semi-cured and hardens. This is well visible around the supports because of the capillary effect (attracting the rubber to stay around the supports). The effect is very strong when the supports are touching horizontal surface - the residual resin can’t flow away and stays much longer on the surface and gets exposed by the laser beam.
FormLabs never mentioned about this problem but it’s there.
The solution is to avoid supports on horizontal surfaces - tilt the detail to 40-70 deg, try to think how the resin can flow out when the build platform is lifting up.
After knowing when the resin parasitic curing effect is stronger I managed to print the same failed details with great precision and excellent surface finish. Sometime you have to “sacrifice” some surfaces in order to get good details on others surfaces.
As parasitic resin curing depends on the time the resin is exposed to reflected laser light, it’s stronger for high resolution prints (like 25um) than low resolution (100um) prints. If you’re not aware of this effect sometimes you can get better quality prints on 100um resolution than on 25um.
Another possible reason to get such ugly resin deposits is when you take the part out from the printer and you start washing it in IPA - if the washing tank is close the windows or under direct sunlight the resin which is surrounding the supports (due to capillary effects) can cure in seconds. Try to wash the details in darker room, away from windows and sunlight, try to minimise the time from taking the detail out of the printer to placing it inside IPA.
Thanks for commenting.
Your photos of parasitic resin curing on the support tread, “Bad prints out of brand New Form 3” helped me greatly when troubleshooting my own Form 3.
I am awaiting a new printer, after RMA’ing the faulty one. Since many commenters on the other thread seemed to find improved quality for various resins after several releases of new firmware and Preform software, I will be interested to see if the same problem occurs with a new machine, while still printing Castable Wax resin @ 25 microns.