Adjusting layer exposure time for different layer thicknesses

Question

I purchased a bottle of Siraya-Tech Simple Clear and Siraya-Tech has good documents on their resins with printing guidelines like for the simple clear (see their Simple User Guide).

This gives good curing times for different types of resin printers, but they are all listed for 50 microns layer height. If I wanted to print at different layer heights, I am assuming the curing times would need to be adjusted, but I don't have a good feel for how much they would need to change.

My first print was the Make: Rook Resin Printer Torture Piece, and given how short it was, I thought I would try pushing things to the limit and printed it at a 10-micron layer height, but I used the curing times in the guide above for the Elegoo Mars (figured it was the most similar to my actual printer the Halot-One), and as soon as I started the print I realized that I probably should have changed the layer exposure times. I was shocked how well it turned out for using the times for a 50-micron print, but there were parts of the print that looked like there may have been a little bit of light bleed because of the longer exposures for the thickness, and the print definitely took a long time for how small of a print it was.

So, my question is, if I have good times for a 50-micron print, are there rules of thumb out there, or have experiments been done, for how much to adjust the exposure times if you want to do a 10-micron print, or say a 100-micron print? I would imagine it's not as simple as reducing it by 5x for a 10-micron print or doubling it for a 100-micron print.

Key parameters that would need to be adjusted:

1. Exposure for initial layers
2. Number of initial layers
3. Layer exposure time

Answer 1

Based on my experience, cure-time and thickness increase or decrease is not linear and it is mostly curve. For example resin rated for 50 micron 5 s cure time. You should expect:

• 25 micron - 3.2 s
• 50 micron - 5 s
• 100 micron - 12 s

If a resin manufacturer do not provide specific cure time for thickness you want, you should always print calibration objects.

You can cure specific range of thickness depend on resins chemical properties (eg. uv blocker and photoinitiators), usually for non-specialized resins, you may print 1/2 or 2x of the suggested thickness. So you cannot print 10 micron for resins which designed for 50 micron thickness. For some specialized resins you can only print with the rated thickness and nothing else.