Last year, I got access to a galvo fiber laser, and had a ton of fun etching designs into metal (you can check out my laser-tattoo’d coffee pot & video here: Coffee Maker).
I’m wondering, are metal-etching lasers available in CNC form vs galvo scanner? The Galvo scanners are quite expensive here in Colombia - and possibly difficult to repair/service, so I was thinking that CNC may be simpler.
My goals are to etch interesting designs into metals like steel. I have a CNC router, and am building out a community makerspace / entrepreneur lab.
Can someone help educate me on this, and perhaps share useful links / product recommendations? Looking to understand the underlying tech (example: CO2 vs Fiber - what does it really mean under the hood, why does one wavength affect materials so differently, and then products/tools - why CNC vs Galvo scanner? I saw that my CNC can support a laser instead of a spindle - what’s the benefits/drawbacks of that. I’m impressed by Galvo speed!)
The galvo is not the expensive part, as I understand it.
A fiber laser is one where the fiber is an active part of the laser system in which the light is amplified by the stimulated emission of radiation (thus “laser”); it doesn’t just guide the laser beam from one point to another. They typically dope the fiber with rare earth elements to control the wavelength.
It’s a compact way to get relatively high power at certain convenient/useful wavelengths. Like CO2 lasers, they are infrared, but at much higher frequency. Something like 700-2000 nm, and commonly just over 1000nm (e.g. 1064nm I think is common).
CO2 lasers primarily lase at 10,400nm and secondary at 9,400. Closed systems that are electronically plasma excited (what hobbyists use) are limited to power that can only cut or mark very thin metal directly. They use a special gas mix including helium to keep from forming CO that permanently poisons the tube. Much more expensive RF excited lasers can have higher instantaneous power which can better mark or cut metal. For cutting thick steel, they use open systems that keep flowing in fresh CO2; those can be many thousands of watts.
I’m not qualified to describe the physics for what causes materials to transmit, refract, absorb, or reflect different wavelengths.
Generally when we think of CNC machines, they are the large milling type or something, however the same thing happens with any of what we call gantry type lasers. Mine is similar to this one.
Depends on if the material absorbs the beam and how much of it is absorbed or reflected.
Most fiber machines have three basic components. The control board, the laser source and the power supply(ies). This controls the basic laser and will interface to a galvo.
Most interesting is the laser source… Fiber lasers, in simple terms, work like this.
The fiber is the amplification medium. Usually there are pump diodes that pump the fiber up and some way to let it out, such as a Q-Switch (just like Q in a radio) and a trigger type.
