Converting existing Diode Laser Frame to CO2

Hello friends! Firstly - thanks for such awesome community, I have studied a lot from this forum! Currently, I’m in a process of building DIY CO2 laser on my Neje 3 max frame. In general the process looks to me more-less understandable, but there are some specific moments which I kindly ask you to help me to clarify, it is related to safely, hardware and electronics. I will start from the safety:

  1. as far as I know any acrylic will block CO2 laser reflections, I also know that opaque orange acrylic will block blue diode laser, my question is - would transparent orange acrylic block blue diode laser reflections as well? Maybe someone with blue diode had experience on cutting transparent orange acrylic, does the laser just goes through or does it actually cut?
  2. what would be the best and simplest way to implement interlock to enclosure?
  3. how to handle the high voltage power supply in a correct way, should I isolate it with some rubber pads while mounting, or it will have no safety effect? Should I do additional grounding, or the one which has regular power cable with 3 pin plug is enough, and it is grounded by default?

Many thanks for your replies!

For your first question:

So while Plexiglas 2422 doesn’t come with a certificate, it is our understanding that it has the same dye that is in the certified plastic. It is possible, of course, to buy plastic that is tested and certified for blocking 455nm laser light.

I’ll leave the other questions to others.

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many thanks for your reply, does it also mean that any safety googles designed to protect from blue diode laser will protect from CO2 ?

There’s a link in Why orange plastic for CO2 lasers? - #9 by mcdanlj to a post that goes into a lot more detail on acrylic transmittance. Apparently thickness really is important! I am not an expert here, I’m just a collector of links using them to make my own decisions for my own laser…

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Note: Safety glasses are not a way to avoid nor do they replace interlocks.

  • what would be the best and simplest way to implement interlock to the enclosure?
    Generally, add microswitches on all accessible areas and connect in serial to the WP pin on the LPS. The exact circuit will depend on what supply you are using.

Post a picture of the LPS you are using.**

  • how to handle the high voltage power supply in a correct way,
    should I isolate it with some rubber pads while mounting,
    You definitely do not want any electronic enclosure floating from the ground. You want the LPS and the cathode of the tube tied electrically to the frame.
    The mounting screws and the FG pin usually provide adeuate connections. Depends on exact supply.
    or it will have no safety effect?

Should I do additional grounding,
The frame and the FG pin on the mains connector should be enough. I use a stud in the frame and star pashers on the ring tounge.

or the one which has a regular power cable with 3 pin plug is enough, and it is grounded by default?
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It should be. Thoroughly check that the ground pins and cases on all electronic elements are electrically at ground. There are lots of posts on this forum about grounding design for minimal noise. Don's Laser Things: Search results for grounding

Other things to consider.

  • Keep control electronics wiring as far away from motors and the LPS as possible.
  • Use single point, not daisy-chained grounding designs.
  • Keep sensor and control wiring as short as possible
  • Use as large as practical ground wiring
  • In sure all metal and operator-accessible surfaces are at safety ground.
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