Surface defects (Bubbles/Voids)
Hello,
I am struggling with printing parts over and over again. It is everytime the same issue: My prints suffer from surface defects, that look like bubbles. I need to say, that to save weight and material I hollw my prints to about 1.5mm wall thickness, but I make sure, the part can "breathe" by making holes close to the print platform. I fill the vat to between 70 and 100% prior to a new job and I use Prusa resins only so far. I filtered my resin, cleaned the screen, but nothing helps. The problem occurs with all different colors, the parts I am showing here were printed in transparent resind and got a grey spray primer afterwards.
I looked carefully at the slices , but the job is ok without any layer defects or voids. You can also see, how the voids appear at slightly different locations, which speaks against file or screens issues. Except for this problem the part quality is phantastic and allows me to airbrush my parts right away without any sanding. But the need to fill and sand these holes is something I definitely need to overcome. Next thing, I would try is to generally lower the tilting speed to avoid potential cavitation issues.
Any thoughts?
kind regards, Ralf
Update
I was able to track down part of the problem. My FEP film had a tiny hole. I drained and washed it, then filled it with water. No problem. Next I lowered the surface tension of the water with soap and it started leaking close to the center. I installed a new film as the old one already has done quite some prints. The bubbles as shown in the pictures are gone, but I still have surface defects. I have taken some macro shots. To me it looks like there are tiny delaminations, which sometimes develop into a bigger problem, looking like rough streaks. Most of the time the problems occur at exposed/convex areas. The angle of these areas at printing is nearly upright. Again it was the transparent material I primered the parts to make the problem visible.
This print was done with 8sec instead of 5sec tilt time, did not improve it.
kind regards, Ralf
