Dimensional Accuracy Best Practices

[hillaryan]

Hello,

I have been playing around with a new printer and reading through Jan's fantastic blog. He makes a suite of suggestions around improving the accuracy of prints, especially those that are printed directly on the build plate. Here is my understanding of how to implement his suggestions in UVTools. Please let me know if this makes sense:

There are four major sources of dimensional errors:

Blooming

• Caused by beginning exposure before z motion has stopped and the resin squeeze has completed. Possibly other causes as well.
• Addressed by increasing wait times via "Wait time before cure" suggestion

Bleeding:

• Caused by optical effects
• I am curious how this is best addressed. Jan's calculator [https://yaqwsx.github.io/printer-calculator/#/shrinkage] spits out a constant number: say 50um. In Lychee, I would plug this number into the Compensation field under the resin settings. Can I affect this compensation in UVTools?

Shrinkage:

• Caused by the physics of resins
• Addressed by using XYZ Calibration followed by Resize, or using the shrinkage values from Jan's calculator directly with resize.

Elephant's foot:

• Caused by a combination of blooming and increased exposure time in the first layers
• Jan seems to address this through wait time and exposure control, which has been implemented into the "Wait time before cure" suggestion
• There is also an elephant foot calibration which seems to work by calibrating erosion. Is it recommended to use this tool in light of Jan's work?