Fixing Misprints and Print Defects Caused by a Dirty Optical Light Path

Overview

Extra cured material or surface defects on your prints are often caused by light scattering, which happens when the printer’s optical light path is dirty or obstructed. A dirty glass or mirror can scatter the curing light, resulting in unwanted resin being hardened in unintended areas.

This article explains how to identify, clean, and resolve these issues.

1. Identify the Cause

If you notice cured material appearing where it shouldn’t, it’s likely due to light scattering in the printer’s optical system. This usually indicates:

• Smudges or fingerprints on the optical glass
• Dust or residue on the mirror beneath the resin tray
• Debris or floating skins in the resin

2. Inspect and Clean the Glass

You can check for smudges or dirt by shining a light onto the glass:

1. Use a torch or your smartphone flashlight.
2. Shine the light at the glass from different angles.
3. Look for any streaks, spots, or cloudy areas that indicate dirt or residue.

Once you’ve located any marks:

• Clean the glass using IPA (isopropyl alcohol) and a soft, lint-free or optical cloth.
• After cleaning, give it a final wipe with window cleaner to remove any remaining streaks.
• Recheck the surface with your light source to ensure it’s spotless.

3. Check the Mirror and Resin Tray

If the issue persists after cleaning the glass:

• Inspect the mirror below the glass. Shine light straight down through the glass to look for any layer of dust or dirt.
• Make sure no debris or cured resin is floating in the resin tray. Clean or replace the resin if necessary.

4. Prevent Future Issues

To keep your prints consistent and defect-free:

• Clean optical components regularly.
• Cover the printer when not in use to prevent dust buildup.
• Handle glass and mirrors carefully to avoid smudges.

Summary

Related topics:

Print defects, Cleaning, Maintenance