Lightobject.com Support Forum

I just completed building my laser table with a 4'x5' footprint. It has a 100w reci laser tube on it. I set up the bottom right corner as the home position, because thats what I am used to working with on CNC routers. Unfortunately I'm not getting the power that I should on the laser. When trying to cut 1/4" acrylic at 5mm per second, it maybe goes 1/16" deep. The alignment looks good. Does it make sense that a beam traveling approximately 8 feet to the laser head would lose that much power???

Specs:
100w Reci Tube laser
150w power supply
Water temp is maintained at about 66 degrees
PWM is 20000

Any ideas would be appreciated...
Thanks..
Chris

Have you tried cutting at the closest possible position and made a continuous line moving away from that nearest point? That would confirm/deny your idea of whether or not the distance is making that big of a difference.

I did move the gantry up the table where the distance from the laser to the focus lens was probably 4 feet and it didn't seem to make any difference.

powerfade wrote:I did move the gantry up the table where the distance from the laser to the focus lens was probably 4 feet and it didn't seem to make any difference.

Yeah, but did you try at Top-Left (assuming that's closest to the laser) and try cutting separate lines on each axis from there? Does the strength diminish along either line? It could be that you're just a hair off which just puts you further off the farther out you go. Given the size of the materials you'd need for that test, you could always sub a piece of masking tape on the air-assist head (again, assuming you have one.) Test fire on low power at two positions: Top Left Limit and Bottom Right Limit.

I suspect you'll see something similar to this:
That's my crappy approximation of a piece of masking tape. The white hole represents the hole on the air assist. The red dot is Top-Left-limit (or closest to laser), the purple Bottom-Right-limit (furthest.)

I had enough problems with a small table, I couldn't imagine trying to align a table that large.

-Tod

Edit: Another note -- make sure that your table and cutting bed are perfectly level. If there's any slope away to the extremities, you could be de-focusing just enough to diminish power.

Hey Tod.. Thanks for that. I had my buddy come over with his thermal camera last night and we were able to get it lined up and cutting nicely . It was mostly an alignment issue. So you were right. We used that method of the masking tape over the lenses and firing at low power. Worked like a charm.

I haven't put a beam expander on it yet, but I think that might be next.

Thanks.
Chris

Excellent news! I'm glad that you're up and cutting!

-Tod