Explanation on Laser lens sizes?

[Trent Sprenkle]

Hi guys! I new to the world of laser etching. My company bought a ULS 40 watt C02 last year and i've been the guy running it. It's awesome!! My question is laser lens sizes. We have a 2.0. I know there are other sizes but what's the difference? I come from a photography background and know about Depth of Field and from what I gather the lens number has something to do with how much "in focus area" the lens has. We do a lot of vinyl (no PVC) so our 2.0 is fine for a flat surface, but we're getting into mugs and pens,etc. On some items I have to do two passes and move the table up or down to get a proper etch. We don't have a rotary attachment. So, wouldn't a 4.0 lens give me more focus area and eliminate the need for doing another pass?

Thanks,

Trent Sprenkle

[Kev Williams]

Here's a link to a page on laser lenses, it's kind of a long read but mostly easy to understand--

http://www.parallax-tech.com/faq.htm

[Mike Null]

The 2.0" lens is the best all-around lens for engraving. I would not recommend a 4.0" lens for your machine as I doubt that you have enough power to use it effectively. While a 4.0 has a larger focus area I believe you will distort your image by using it on a cylindrical object. You would be better served by buying a rotary attachment for your machine.