[SimonArthur]

I have a brand new problem with my Artsign JSM40 (very similar to the Rabbit and all the other Chinese lasers).

The machine has been working fine for a while now, though I haven't used it much. When I use the "Laser Test" buttons, the laser fires just fine. Revently, however, when I try to engrave using NewlyDraw, the carriages move, but the laser never fires.

I've tried power cycling both the laser cutter and the computer, as well as re-installing NewlyDraw, and reseating the parallel cable on both ends. None of these solutions helped.

Has anyone ever seen this problem before? Any ideas on what might be wrong?

[grzegorz1965]

I had similar problem.
check the conection of PWM signal in terminal of high voltage power supply.
It must be well attached by screw.
sorry for my english

[SimonArthur]

Very interesting! Can you tell me exactly which wire to check? Can you post a photo or diagram?

I cannot figure out how the control board (the one with the parallel port from the computer) tells the laser to turn on.

[lamicron]

Try to reinstall the software, this chinese softwares have to be installed at least 5 times to get it complete!!!
Luis

[grzegorz1965]

I realized my laser (LC1280) is different type to yours.And powe supply is diferent too.
so first try reinstal software .
Maybe Lamicron is right.
then we try to find soution.
Sorry.
Grzegorz

[SimonArthur]

The latest info:
I decided to swap out the control board for a Xylotex stepper driver. I'm using EMC to control the machine. This gives me a lot more flexibility, including allowing me to control the cutting speed accurately, something that I haven't been able to do before. My inspiration was found on the following web pages from people who have done the same thing:
http://www.synthfool.com/laser/
http://www.routoutcnc.co.uk/Forum/index.php?topic=17.0
http://alastair.d-silva.org/[catpath]/working-with-cheap-chinese-laser-engravers

I'm controlling turning the laser on and off via a relay board from CNC4PC. I can control the laser's power from software via the spindle speed PWM, something that I couldn't do before.

However, as I was in the process of calibrating the laser, one of the mirrors cracked! I found a couple suppliers for new mirrors. One is ebay user "pkunlimited", item number 360059437707. The other is Anchor Optics:
http://www.anchoroptics.com/catalog/product.cfm?id=361

I found these silver mirrors, which might be more efficient, but cost a lot more, too:
http://www.newport.com/store/product...1089&lang=1033

I suspect that my mirror problem may have been due to incorrect cleaning. Here are a few links I found about cleaning laser optics:
http://www.repairfaq.org/sam/laseratr.htm#atrcln
http://www.coherent.com/Service/inde...page&PageID=40
http://www.coherent.com/Service/inde...page&PageID=38
http://www.lbp.co.uk/Technical/PDF files/cleanoptic.PDF

From now on, I'm going to place some aluminum foil between the laser and the target disk when aligning the beam in order to protect the mirror from contamination.

Other miscellaneous notes:
I had major problems with realtime latency in EMC until I applied the SMI fix:
http://wiki.linuxcnc.org/cgi-bin/emc...ixingSMIIssues

The steppers required the lowest current setting on the Xylotex in order to function correctly. The left-to-right axis required me to move the controller into half-step mode.

Artsign does not respond to e-mails.

SheetCAM is currently my leading choice for generating G-Code from DXF files. The fact that it can generate lead-in and lead-out as well as the fact that it runs on Linux are both very helpful. And the beta version is free to use.
http://www.sheetcam.com/

[SimonArthur]

By the way, does anyone want to buy either of the following:
1. My old control board.
2. A copy of NewlyDraw with dongle.