40W CO2 Laser Engraving/cutting Machine Training

[JimSC]

I am new to laser cutting and right off have some issues.  I would like to get some training. Any ideas? I have a $400 chinese laser ( 40W CO2 Laser Engraving Machine). I have no illusions that this machine will do what I would like to do but I thought this was a good way to learn without laying out a bunch of money.

I live in the Fort Mill, South Carolina/Charlotte, North Carolina area and would be willing to travel. Any online classes? 

Jim

[Domagoj T]

I have that thing and could answer your questions.

I opted for the 20x30cm work area, which is usually enough for my purposes, but results in more scrap material than necessary and some limitations.
It does cut 3 mm plywood easily and cleanly (not any plywood, it must be special kind for laser cutting), acrylic and card stock.

A big limitation is the fixed height of bed in my machine (no z axis adjustment). It limits you to thin sheet material.
Air assist seems to be important, as well as proper air evacuation.
Water cooling pump that came with the machine seems to be ok.

One thing I will say is that I use it much less than I expected to, and given the experience I have now would not buy it again. Don't get me wrong, the machine does everything I expected it to do, but the controller is locked to the crappy software that is very fiddly and not intuitive. I did buy a replacement one, but never got around to installing it. The reason I don't use it much is primarily due to general lack of time and plenty of other projects I have on hand.

Edit:
Oh, I've just read your post again and realized that you already have the machine. Before writing all this I was mistakenly under impression that you want to buy one.

[JimSC]

You want another one? LOL

Thanks for the reply. The Big issue is the machine lights up, meter works, but the laser doesn't come on. I read that the computer does not have to be hooked up in for the mirrors to be adjusted. Do you know if this is so? I have some one who can help with the software but I don't want him to do that if the machine doesn't work!

Thanks again,

Jim

[Domagoj T]

Well, there are more models of the 40W laser than there are units, so this may not apply to yours but mine will fire up the laser no problem without the computer. It has two buttons, one toggle and one temporary. The toggle one is enable/disable so you can do a "dry run" (run the program without powering the laser). The temporary push button overrides computer control and turns on the laser. The power is adjusted with a potentiometer.
Even if the mirrors are misaligned you can test the tube itself by looking at it (wear UV blocking glasses). Open the cover and when you manually power the tube via the push button, the tube should have a visible light beam in the middle along the entire length. The beam should be about 10 mm wide and light pink/violet in color, definitely not red/orange). If you put a piece of paper at the business end of it and fire a short pulse, it should burn a hole in the paper. I keep my laser at below 15mA and at that power it takes maybe a tenth of a second for the unfocused beam to punch through the paper.

If that works fine you should check mirror alignment. Start with the first one (right next to the tube and work your way towards the lens. The first mirror should reflect the beam at the middle of the second mirror and the spot should stay in the middle no matter where you move the Y axis. X axis is not important at this time.
When you have that aligned, check the second mirror (on one on the Y axis). Again it should reflect to the middle of the next mirror and the spot shouldn't move regardless of where the X axis is.
When I was first aligning them my beam was hitting the edge of the mirror and I thought it was fine, but overall result wasn't really good. I went back and redid the alignment which made a big improvement on the overall cutting capability. I also used that opportunity to replace the mirrors, since the ones that arrived with the machine had some discoloration and I was installing a new lens anyway. Clean mirrors are incredibly important and even a tiny speck of dust can have dramatic influence on the performance.

For alignment I use paper for thermal printers, they seem to give a better idea where the beam is hitting, but regular office paper will do.

[Old Printer]

Did you get the alignment procedure with the machine? As Domagoj said you first need to be sure the tube is firing. Suspending a piece of paper in the path of the beam from the tube to the first mirror should tell you that pretty quick. Rig something up to hold the paper in place with the top closed so you don't need to defeat the interlock. If you have a beam fire command available from the control panel that is best, but if working from a computer be sure you are in vector mode by selecting it in the driver and also be sure the line width in your drawing software is set to hairline or .001 or the driver will see it as raster and you will only get minimal power. Bouncing around a container from China it is not hard to imagine the optics are miss-aligned.

[CJay]

I got one of the K40 lasers last year, a Christmas present to myself, the story is elsewhere on these forums but:

First things first, you *MUST* inspect the internal wiring of the unit, mine was shocking (could have been literally).

 (this is not an attack on you, you're dealing with thousands of volts and it's not a job for a beginner)

These things can be dreadfully assembled with no earth connectivity, badly crimped wiring, shoddy assembly.

If you're not confident in your abilities/competency then find someone who is competent.

Once you've got that sorted out and ensured the casing is earthed properly then you can begin.

[beanflying]

In case you haven't found it my non K40 40W Chinese Laser is here. Adjustable height bed is a great improvement if you can engineer it. 

https://www.eevblog.com/forum/reviews/40w-300x200mm-laser-cutter-engraver-vollerun/msg1665956/#msg1665956

[beanflying]

Re the Software either of these two help out with or Eliminate Laserdraw 

Inkscape Plugin http://www.scorchworks.com/LaserDRW_extension/laserdrw_extension.html (still uses Laserdraw for the output)

No Laserdraw needed http://www.scorchworks.com/K40whisperer/k40whisperer.html (does not work with all control boards used in some K40's)

What both of these do for you in give you a way to bring in SVG or DXF files from 'proper' Cad or Drawing software. This guy deserves