How to Replace the Polarizing Filter on a Resin 3D Printer

Many resin 3D printers utilize an LCD screen topped with a polarizing filter to selectively cure resin during printing. If this delicate polarizing film becomes scratched or damaged, it can cause print failures and errors. Thankfully, the polarizer can be replaced in most resin printers without needing to swap out the entire LCD screen assembly. Here is a general guide on how to properly replace the polarizing filter film.

Step 1: Purchase Replacement Polarizing Film

You will need new polarizing film to replace the damaged filter. Check the specifications for your printer model and LCD screen size to determine the required dimensions. Many brands sell replacement LCDs, but you can likely find inexpensive generic polarizing film sold in packs on sites like Amazon and AliExpress. Ensure any film you purchase has adhesive already applied. Get your polarizing film here:

Step 2: Remove the Existing Film

Carefully detach and scrape off any remnants of the old polarizing film from the LCD screen using a plastic scraper. Be very gentle to avoid scratching the screen. Thoroughly clean all adhesive residue off the display using high % isopropyl alcohol and a lint-free cloth.

Step 3: Test Orientations with an Exposure Screen

This is the most crucial step to get right. The new film must be precisely aligned in the correct orientation to properly filter light from the LCD. If your printer has an “exposure test” mode, use this to find the optimal angle. Rotate and orient the new film while observing the test pattern until it appears dark and crisply defined.

If your printer lacks this mode, you may need to do test prints to dial in alignment. Mark the correct orientation once found.

Step 4: Cut the Film to Size

With the right alignment marked, carefully measure and cut the new film to size so it can cover the entire LCD screen surface. Leave a small margin of extra film on the edges. Double check measurements to ensure proper fit.

Step 5: Apply the New Polarizing Film

Gently lower the new film onto the screen using your alignment guides. Slowly press down while avoiding bubbles and debris under the surface. If any bubbles appear, gently press them out towards the edges with a soft tool.

Step 6: Test for Successful Installation

Run an exposure test or do a test print if available. The pattern or print should come out crisp and clean when the film is aligned correctly. If issues persist, try re-aligning the film or replacing it if defective.

With care and patience, the polarizing filter can be replaced successfully, avoiding the cost of a whole new LCD screen. Your resin printer should be ready to resume printing!

See this video for reference:

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