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Mirror coating repair

  • 9 February 2023
  • 3 replies
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Userlevel 7
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Hi everyone,

 

My question doesn’t relate to OpticStudio, but I’m hoping to find someone who can help me here so I hope you don’t mind.

I have a 2-axis galvanometer scanner, and one of the mirrors seems badly oxidized. The reflection of the defective mirror is just above 0.6 (while the other one is around .94). We can still use this scanner but we are a bit on the edge with our light source power. The company who sold the scanner has discontinued this product and doesn’t want to repair a single unit. Ideally, we don’t want to buy another scanner. Do you know someone who would be willing to repair our mirror? It had a broadband visible coating.

Thanks for your help and take care,

 

David

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Best answer by Mark.Nicholson 9 February 2023, 19:07

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Userlevel 7
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Try Ty Guernsey at Guernsey Coating Labs https://www.linkedin.com/in/ty-guernsey-45001329/

Userlevel 7
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Thanks a lot @Mark.Nicholson. I’ll soon send them the mirror and they’ll try to redo the coating. *fingers crossed*

Userlevel 7
Badge +2

Guernsey Coating Lab stripped the original coating and made a new one. I think I’ll write a small article about the repair of the galvo, but just some words of caution for anyone trying something similar:

  • I had to send the mirror only to Guernsey Coating Lab, meaning I had to detach the mirror from the motor. The manufacturer recommended a soldering iron at 300 deg C to soften the epoxy and remove the mirror, this didn’t work for me. I tried to burn the epoxy raising the soldering iron temperature to 400 deg C but the epoxy didn’t burn well and I felt that if I kept the galvo at this temperature for too long it would damage the motor. Eventually I made a jig with a 15 mL falcon tube and dipped the epoxy bond in dichloromethane (I used the reagent out of the bottle, its close to 99% dichloromethane) for roughly 48 hours. Don’t dip the whole motor, only the mirror and the bond! I checked if I could remove the mirror before, but only some bits of epoxy came off. It was only after the 48 hours that without much force, the mirror detached from the galvo
  • Guernsey Coating Lab were able to redo the coating because our mirror had a silicon substrate, they might not be able to do it if the substrate is different, such as beryllium, check with your mirror substrate and with Guernsey Coating Lab

Take care everyone,


David

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