Laser engravers

[Chris Cramer]

I decided to replace the spindle on my homemade milling machine with a 7.5w laser module to create a laser engraver. the Laser isn't as powerful as I thought it would be, I expected it to able to engrave metal but the claim of it being a 30w laser pointed to the electrical power where the optical power is only 7.5w. It can still engrave wood, plastic, coated metals, etc; but it can only cut certain materials yp to 4mm thick.

 

[Johnwa]

The diode power ratings are a real gong show. I have one that is rated 5.5W output, at least I hope it is.
Even a 40w CO2 laser won’t directly engrave metals. though. There are some chemical processes where the metal is coated with “Cermark” or dry moly lube prior to lazering. CO2 lasers were used but they seemed to work at low power levels. A diode laser might work.
It’s on my list of things to try, but I’m no longer allowed to use my laser in the house until I rig up a better ventilation system.

 

[6.5 Fan]

Was just watching a utube video of a guy called Eric Cortana with his new laser engraver doing metal. Looked impressive but i didn't check to see if he said what equipment he bought.

 

[Chris Cramer]

There are some more high quality modules manufactured in America, like endurance lasers that are up to 8 - 10w; but they cost a great deal more. Diode lasers are better for engraving metals, because the wavelength also makes a big difference. CO2 lasers don't work well on metal because of the wavelength, thats why fiber lasers are used more often for cutting metal.

 

[Janger]

What happens if you just go really slow? Can you then mark metals? What happens if you use an acid etch pen and evenly cover the surface then laser it?

 

[Janger]

https://www.spilasers.com/industrial-fiber-lasers/how-fiber-lasers-work/

fiber laser explanation

 

[Chris Cramer]

Bare metal cant be engraved even if you go very slow. Unless it is treated or coated with engraving compound or paper, then a high percentage of the light is reflected of the surface of most metals before it delivers enough heat to engrave the metal. copper and aluminum are especially difficult to engrave, not just because of their high reflectivity, but also their high heat conductance. high powered fiber lasers work well for cutting and engraving metal, because they deliver enough heat upon contact. Other materials that aren't as reflective or conductive but are still hard, can be engraved by traveling slow, and running multiple passes. I might try engraving a tile, as that was on the list of things they claimed this module could engrave.

 

[Chris Cramer]

I dont know if there is any substance that would etch the surface as soon as the heat from the laser is delivered, but the laser can be used to cut the design out of some laser tape which protects the rest of the metal from the acid.