I am thinking about laser safety on my L7X.
Let me know what you think and/or alternate ideas…
Some thoughts on laser diode module exposure modes [plan to test these]:
- The laser focus is 10mm off the surface and it’s not likely that a beam is reflected upward to a user?
- The laser is low power therefore it’s unlikely a reflection will penetrate a clear acrylic cover above and a couple of inches away from the laser head.
The design concept I am thinking of is:
- The side frames are solid material (colored acrylic) the top is clear acrylic with a hinge and interlock switch. A shield above the laser module may be effective protection.
- There is a plate above the laser module shielding light from reflecting upward.
- Put NO microswitches on the bottom edge of the frame of the unit. They shut down the lasers 12V when the frame is lifted off the surface or tilted.
- I am thinking of a 12V relay whose contacts are in series with the lasers 12V and also indicate with a flashing light when the laser is enabled. [not as fail-safe as inline switches but good enough?]
- An Estop switch on the main 120V input. [not really an Estop, do not directly stop steppers, but good enough since everything in this machine is very low mass?]
- Tilt switches [never had good luck with these at low voltage]
- Arduino-managed accelerometer and 12V relay (complex & not really fail-safe?).
Here is a simple method some use to shield the laser module on CNC units. I cannot see any glaring practical flaws using this on a portable machine if it is combined with the interlocks above. Do you see any use cases where this could be unsafe??
I could use filter material on the entire enclosure but that would not meet my goal of low cost.
This material is expensive: 250nm to 520nm Laser Shielding | J Tech Photonics, Inc.
I plan on an enclosed cabinet with an evacuation port that connects to a fume filter box that is about the size of a small vacuum cleaner.