New to Laser engravers

[Mohammed Hasham]

Hi, I'm new to this board but have read alot on this board. I just bought a laser engraver from china (big mistake I think) and now I'm having problems. I'm trying to engrave on glass and the letters seem they are bitmap format. The image is really vector. I don't know how to focus my engraver because it's not auto focus.
Anyone have any ideas?

Thanks
Mohammed

[Joe Pelonio]

I have never seen one of the Chinese lasers, but I can tell you how it's done on my laser. There is a focus button. When you press it the head moves to a point over the material. Then there's a knob that raises and lowers the bed that the material sits on. I have a metal focus tool that mounts on the head, and is held on magnetically. I raise or lower the bed until the tip of that tool just touches the material. Then press enter button, and reset button.

[Mike Null]

It's probable that you have a 2" lens in your machine. (It could be a 1.5", 2.5" or even a 4") But for purposes of trying this experiment we'll assume it's 2".

Take a ruler and measure 2" from the bottom of your lens (be sure it's the lens and not the bottom of the lens holder) to the top of the surface you're engraving and see what result that gives you. Move your table from there to adjust the focus. When you find the correct focal length make a small tool that you can use as a focusing device with all jobs.

If you're using CorelDraw your letters will be rastered unless you're doing outline only with a hairline outline.

[Mike Mackenzie]

The other method to determine focus is to use anodized aluminum. If you can get a continuous on beam then just fire the laser adjust the Z up and down to get the spot on the aluminum until it is the smallest and brightest.

At that point measure the distance from the bottom of the lens to the pc of material it should be somewhere around 1.995 (2.0).

This is how most laser companies calibrate the focus tools.