I am about to start designing a CO2 laser cutting/engraving machine (size +- 2,5x1,5 meters), but before I can start I have a question regarding the Z axis of a laser machine.
I see many people constructing a complete movable bed as a Z axis which can go up and down. My question is: isn't it easier to make a Z-construction for the Lens? So the lens could move up and down (closer and further away from the material)? Or is there another reason behind the fact that people are using the bed as a Z-axis and not the lens?
It would depend on the purpose of the Z axis. The dynamic focus heads are typically used for cutting sheets that are not perfectly flat. The adjustable bed is used for setting the focal distance before the cutting/engraving operation.
You could adjust the lens up and down. That adjustment is limited but probably well within the thickness variation you can cut. Engraving thick materials is another story. If you don’t have macro Z adjustment you need to have an alternate way to remove the bed so you can clean it.
I would like to make a CNC Laser with these measurements. The problem is that not much knowledge and I look for a tutorial (DIY), to be able to guide me.