LaserUser.com Forum (formerly RDWorksLab)

I'm a new laser owner. I've had mine about two weeks. No experience whatsoever with lasers, or CAD or CNC. I'm retired. No business. I just have the laser for fun in my woodshop.
I tried yesterday to do some power test with some 3/4" acrylic sheet cut 1 1/2" wide. I stood it on edge, so I'd have plenty of depth. I unhooked the x axis plug (where you plug in the rotary device). I did the same program Russ did. 10mm no output, 6mm cut, 10 mm no output. I did it at 1mms. So I'd have a 6 second burn. I did 20% power up to 90% power burns with the nozzle in place. The depth of cut stepped up with each increase in power. I measured it very carefully through the 3/4" acrylic. I didn't see the expected drop off around 70%.

Any way, I initially tried to do the test as Russ did it with the nozzle off. What I found out was the nozzle tube is in a collet. I can set the nozzle any random height I want.

Where is it supposed to be? I pushed it all the way into the collet and tightened the ring nut. So it is as short as possible.

What is the effect of making the distance longer?

I got my amp meter yesterday and will be installing it today. I know that will help me answer my questions on power tests.
Thanks for your help.

RP

The length of the tube does not matter- some people loosen it and use that up and down position to set the focus- as you would have to if your bed is not movable/motorized. I have a remote control that can be set for two different speeds so I set the focus that way. If you have a pass-thru or a rotary device you may have to lengthen/shorten the tube to suit.

The other use depends on the construction of your cabinet. In my case, a longer lens tube allows me to feed material in through the lower door so I can use longer pieces eliminating some waste. Others have cabinets that allow the same thing with the tube all the way up coming in the main door. Basically it just gives you options.

Robert Edington wrote: Tue Mar 03, 2020What I found out was the nozzle tube is in a collet. I can set the nozzle any random height I want.

Where is it supposed to be? I pushed it all the way into the collet and tightened the ring nut. So it is as short as possible.

What is the effect of making the distance longer?

I've discovered that if I make the nozzle tube too short I can't get the 6mm gap above any thin material I'm trying to cut on the machine's original bed (even with the bed raised to the very top). The smallest I can get is about 10mm.

Just a bit of a nuisance when you're chopping and changing what you're cutting.

The farther the lens is from Mirror 3 (i.e. longer lens tube), the more accuracy is required to get the beam vertical (centered on the lens).

If the beam coming from Mirror 3 is perfectly vertical, you can have a lens tube 50' long, and the beam will still hit the center of the lens. But if it's off by a fraction of a degree, you'll have more problems at greater distances.