Glossary · Setting

3D printing

Exposure time

How long each layer is illuminated in resin printing. Too short, and the layer does not solidify. Too long, and fine details fill in.

Explained in more detail

Exposure time is the most important setting in resin printing and depends on the resin, colour, layer thickness, printer and temperature. On current mono LCD printers, normal layers often need only a few seconds. The first bottom layers are exposed many times longer so that the part sticks firmly to the build plate. Underexposure shows as supports snapping off, missing details or parts that stick to the film, overexposure as filled-in holes, swollen edges and oversized dimensions. You can find the right value with an exposure test from the slicer or from the resin manufacturer.

Where does the term come from?

Exposure comes from photography: a light-sensitive material is exposed to light for a certain time. The setting is called exposure time, and that of the bottom layers bottom exposure.

In practice

• Start with the resin manufacturer's profile for your printer, not with values from another device.
• Change the exposure in small steps and only one value at a time.
• Phrozen recommends increasing the exposure by 20% at a room temperature of 18 to 24 °C, and below 20 °C prints start to fail.
• Resin colour affects the time needed, and profiles often give longer values for dark resins.
• If parts do not stick to the platform, the cause is often a bottom exposure that is too short, cold resin or a platform that has not been levelled properly.

Not to be confused

The exposure time in a resin printer has nothing to do with the exposure of a camera or a 3D scanner. Post-curing after washing is also a separate step outside the printer.

Frequently asked questions

What is bottom exposure?

The first few layers are exposed much longer than the rest so that the part sticks firmly to the build plate. Too short, and the part comes off the plate. Too long, and it is hard to remove.

How can I tell overexposure?

Fine holes fill in, edges look swollen, textures blur, and parts come out slightly larger than designed. In that case reduce the normal exposure step by step.