[brad3378]

It seems like it would be easier to mount the laser to the gantry so you don't have to worry about keeping the mirrors in your optical path aligned - not to mention the added cost of the mirrors.

What is the advantage of using mirrors?

[Exsecratio]

Smaller motors due to the lighter gantry.

A big tube full of water weighs quite a lot. Changing direction is a product of force over time, the heavier the gantry the more force is required. The big flatbeds don't run very quickly even with high power tubes, much over 60mm per second and corners become wobbles.

cheers

Dave

[keebler303]

It also keeps you from having to route water lines through your gantry as well as the high voltage/high frequency laser power wire.

As Dave mentioned though, the primary reason is machine dynamics (acceleration) and the cost of beefier motors, drives, screws, etc.

[tejaswood]

Plus your machine would have to be almost twice as long.. Imagine trying to move a tube that is almost 2 foot long back and forth (depending on the machine).

[rayscott]

I had a customer once that had a cnc router. sometimes they would use the router head for making chips... other times they would use the laser head for making smoke. They mounted an RF laser head to the gantry. The electrical interface wasn't really easy, but it worked. They found that the cutting was ok, because they didn't need to change direction quickly. .. Engraving was nearly impossible. Just TOO much mass to swing back and forth.

The Chinese laser machines present a few problems and solutions. The laser source is a BIG glass tube. This makes it all but impossible to mount the laser on the moving head. The solution is to mount the laser tube inside the back of the laser and use mirrors o bounce the laser beam around the work table. If you keep the mirrors clean, then there isn't much loss during reflections. It is extremely important to ensure a nearly perfect laser beam alignment. If the mirrors don't direct the laser beam correctly, then the laser does not work properly at various sections of the work area.

Ray Scott
Rabbit Laser USA