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Inspecting the Backlight Unit and LPU (Form Studio 1)

Inspecting the Backlight Unit and LPU (Form Studio 1)

If you experience print defects when using your Form Studio 1 printer, inspect the Backlight Unit and Light Processing Unit (LPU) to ensure they are functioning normally. Start by testing the Backlight Unit, then test the Backlight Unit and LPU together.

Warning:

Do not look directly at the UV backlight while inspecting the printer optics.

Testing the Backlight Unit

To test the Backlight Unit in isolation:

  1. Dim the lights in your workspace. This will make it easier to see the light from the Backlight Unit and determine if it is working properly.
  2. On the touchscreen, go to Settings > Tools > Inspect optics.
Starting the Form Studio 1 optics inspection
  1. The touchscreen walks you through the process of removing consumables. Remove the consumables and tap Next.
Removing consumables to inspect the Form Studio 1 optics
  1. Place a sheet of paper on the LPU to protect your eyes from UV damage. Leave the printer cover open after placing the sheet of paper on the LPU.
  2. Tap Next when the LPU is fully covered.
Covering the LPU before inspecting the Form Studio 1 optics
  1. With the paper in place, tap Backlight only. The Backlight Unit turns on while the LPU remains off.
  2. Inspect the paper. If the Backlight Unit and LPU are functioning normally, the paper should be uniformly dimly lit. If the paper does not appear to light up at all, the environment may be too bright. Turn down the lights or use thinner paper, then inspect the backlight again.
Turning the Form Studio 1 Backlight Unit on to test it

Identifying issues by testing the Backlight Unit

  • One or more isolated dark regions may indicate failed LEDs in the Backlight Unit.
  • Larger bands of darkness or the backlight not turning on at all may indicate an issue with the printer’s power supply. 
  • Small bright spots or pinpoints of light may indicate failed pixels in the LPU. 
  • The LED light may appear yellow. This is normal and not indicative of a problem with the BLU.

Contact Formlabs Support for assistance.

A Form Studio 1 printer showing signs of a failed Backlight Unit
Large region of failed LEDs

Testing the Backlight Unit with the LPU

To test the Backlight Unit and LPU together:

  1. After testing the Backlight Unit alone, tap Backlight and LPU. The Backlight Unit and LPU both turn on.
  2. Inspect the paper. If the Backlight Unit and LPU are functioning normally, the paper should be uniformly lit, but brighter than before.
Testing the Backlight Unit and LPU together on a Form Studio 1 printer

Identifying issues by testing the Backlight Unit and LPU

  • If the light is no brighter than during the previous test, the LPU may have failed.
  • If the light is flickering or a section of the LPU does not light up, the LPU may have failed.
  • Small dark spots, typically near the edges, indicate failed areas in the LPU.
  • Localized regions where the light is darker may be due to dust settling under the LPU. Remove the LPU, then clean the underside of the LPU with a non-abrasive wipe lightly wetted with IPA. Clean any other visible dust in the printer cavity, then reinstall the LPU. Also clean or replace the LPU fan filter and ensure the printer is located away from machinery that generates dust.

Contact Formlabs Support for assistance.

Small dark spots near the edge of a Form 4 LPU
Dark regions on a Form 4L LPU

If the sheet of paper does not appear uniformly lit or completely unlit during this test or you have questions about the results of these tests, contact Formlabs Support for assistance.