Support diameter calibration

This file helps you figure out what size supports to use, and quickly check for any problems your supports may have with a specific exposure. Before printing this file, first find your desired exposure using one of the many fast, flat exposure tests that are available. After you've found an exposure that gives you great details, print this file to see which diameter supports will succeed with that exposure setting.

The support diameter is printed above each support. Some common diameters used by slicers:

• 0.3mm: Lychee light
• 0.5mm: Chitubox light
• 0.6mm: Lychee medium
• 0.8mm: Chitubox medium

If a support diameter cannot hold the full weight attached to it, then you need to use a larger diameter when slicing your files. For presupported models that you can't change the diameters on, you'll need to increase your exposure time instead to compensate.

The weight that each support holds is marked by serrations, each serration indicating 1mm^3 of resin. This can be used as a rough estimate of the pressure exerted on the support due to gravity and FEP adherence. Most resins have a tensile strength of 30MPa+, which is well above the pressure exerted on the supports in this test model. If you're fully curing the resin, all supports should be able to hold the full weight. However, since 3d printers aren't perfect, it's common to undercure the print to avoid light bleed ("overexposure") and give better details; after printing, a post-cure brings it up to its fully cured state. Being only partially cured during printing means the smaller support diameters may remain soft or shrunken in size. Their strength is reduced, much less than 30MPa, and that means these smaller supports will fail in the test. If you need a specific support diameter to succeed, you'll need to increase your exposure to cure the resin closer to its rated 30MPa+ strength.

On the backside of the test model is a skewed checkerboard pattern. The length of each square matches the diameter of the corresponding support. You can use this pattern to see what size mark the support will make on your model once removed. It can also be used to double check your exposure settings to see if the exposure is washing out details. High exposure will cause the checkerboard squares to “dilate” or “grow” due to light bleed in the printer's screen and light scattering in the resin. The checkerboard is shown on 5 different angles, so you can see how the dilation varies at different X/Y/Z angles. The closer the area of the positive squares matches the negative ones, the less dilation you have.

This model is open source and made in Blender, so feel free to follow the source URL and modify it for your needs.