how to Select correct laser engraving machines according the materials

You can check the differents of the 3 type laser machine, 

co2 laser engraving machine, fiber laser marking machine, and UV laser marking machine, as follow:

1. CO2 Laser Source: This is probably the most commonly used laser source for engraving. It works with organic

 materials, minerals and some plastics. It does not engrave metals, however it is possible to use coatings that when

 heated react with the metal to leave a mark. CO2 laser sources tend to be the cheapest option. Available in CNC style

 and Galvo laser systems.

2. Fiber Laser Source: This is a more expensive option compared to a CO2 laser source but it is able to mark and engrave metals.

 It can also give good marking capabilities on certain plastics. It doesn’t tend to be as good as CO2 for marking organic materials.

 As the laser beam is about 5 times or more smaller than the CO2 laser beam, it can give finer detail at the cost of speed. This is why

 it is more common to find this laser source in a galvo based delivery system for engraving.

3. UV Laser Source: This can mark most objects and would be my choice for marking glass or crystal. However the beam is smaller than

 that of the fiber laser so job time is increased. This is why it is more common to find this laser source in a galvo based delivery system 

for engraving. It’s also significantly more expensive than a fiber system.