What causes unevenly adhesion to the build platform?
Hello,
I have this problem, that my parts do not stick evenly to the build platform. I tried to increase the exposure time base and the base layers. What has happened is that the parts have adhered very tightly in some places but have still been loose in others.
Now I think it's because of how I clean my build platforms. Here my current work flow. After I removed all parts I leave the build platform in a bath of IPA for about 30 min. After that i wipe off the remaining undissolved resin with wipes. Then I rinse the build platform again with IPA and do not touch the down facing side. Finally, I remove the excess IPA with compressed air and let the build platform dry for an hour until I use it again. What could or should I do differently? How is your approach?
Otherwise, could it be because I'm not changing the IPA bath early enough? After a few washes, a thin layer of resin forms at the bottom of the IPA bath. To avoid putting the platform in the resin layer, I use two small pieces of wood. Nevertheless, I wonder if the IPA is possibly too saturated. Can I measure this somehow? When is the point reached to change it?
What could be other causes that could lead to uneven adhesion to the build platform?
Does the light engine or the Z-axis need to be recalibrated?
Regards
Cem
Comments
3 comments
Brent my friend I am waiting for your answer :D
Build plate adhesion can become a complex topic very quickly.
Primary factor is the first layer thickness. This depends on flatness of the build plate, flatness of the light engine, alignment of the build plate, resin viscosity, and which printer you are using (each model has a different homing method). To find your first layer thickness, try printing a 0.5mm tall object at all four corners and the center of the build area, then measure actual thickness of each one. Variation of 0.3mm is normal on XiP and XiP Pro, and some NXE printers may have variation up to 0.6mm. Most of this is first layer variation and depending on the working curve of the resin (exposure time vs cure depth), the base layer may provide very different adhesion from areas with large vs small first layer gap.
Next you can look at surface finish of the build plate. Roughening to 150Ra gives best adhesion (too much for some materials to come off easily), but will probably not stay rough more than a few hard scrapes when cleaning off the plate. Roughness of 60-90 Ra is historically our standard with most materials and aluminum build plates.
I think it is a good idea to store build plates in IPA or xCLEAN when not used, so it will soften any cured material. You must wipe clean and scrape any cured material from the build surface and remove any cured particles from the other surfaces or slots to not contaminate the bath. Make sure the build plate doesn't have IPA residue that could prevent first layer adhesion. Adhesion seems to be a little lower on a new build plate, likely because trace resin residue in the low spots of the surface act to promote adhesion (a bit like ABS-Juice for the FDM users out there).
I've had similar issues - if it adheres tightly in one localized area (left/right or front/back), the simple fix might be to realign the build plate.
The new build plate is a huge improvement for cleaning, but I've recently been having issues where the outside edges of the build plate have good adhesion, but parts in the middle tend to peel off and fail. I'm not sure whether this is due to the new build plate, but I don't remember having this issue with the old one. Any ideas why the middle of the plate would have poor adhesion? I've mainly been avoiding parts in the center to avoid this, but it would be great to have that useable space again.
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