Looking for spare parts for your K40 laser machine? Check out Cloudray Laser!

A lot of questions lately has been around machines stopping mid job, before the end or right away when starting a job.
This is a issue no matter of your setup, controller type and/or other solutions.

I will go through most common issues with communication for this problems in this article.

1: USB cable and setup
– Most users have a laptop connected to their machine. Make sure all power saving programs/schemes are set to off. See guide here
– If you are using a usb-hub, make sure its powered.
– Change the stock USB cable to a higher quality, shielded USB cable. Keep it as short as possible. You do not need USB3, USB2 is good enough.

2: Interference from the machine and other machines in your house
Several users has reported their machines turning, stopping or losing the connection completely random.
In some cases i could watch it IRL, and we found out that other machines in the house affected the laser. In one case it was a water heater, when it turned on the laser stopped, even as it was in the basement of the house and not close to the machine.
In this case, a EMI-filter will solve this issue. The K40 and the electronics are very sensitive for slightest disturbance in your local wiring, also it sends out a “noise” that can affect other stuff.
In my home my security cameras flip the image 180 degrees and turn on/off randomly with the machine running without a EMI-filter.
Grab a 10-16A EMI-filter made for 250V and install between the internal connector in the machine and the PSU.
emifilter k40

3: Other machinery on the same phase
If you run other heavy machine, like vacuums, compressors and similar machines pulling a lot of power, these can disturb your laser.
For some users it´s enough with moving the machine to it´s own phase in the house, others needs a EMI-filter if there is only one phase where you have the laser machine.

4: Grounding the host computer and the laser together.
Some users has reported making a ground connection between the laptop/computer and the laser machine USB ground has solved their issues.

And as always, make sure your ground is 100% perfect. Do not ground it both on the ground bolt and from the wall outlet, this will cause ground potential differences and might be a source to problems like this.


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We checked Y-axis-stepper on x-output of controller, same problem.
Adjusted gantry more parallel, bit oil, moves easier, same problem.
Now we look for Nema 17HA512H22P2 double shaft <1A.
Do you know where to get?


my new K40 works well, but has problems on y-axis movement on speed higher as 60 mm/sec.
Stepper motor gets very loud, laser moves not to right position.
Anyone with same problem?
Because motor works at lower speed, i think it´s a problem of driver or controller.
Controller is 6C689-Laser-M2, motor 17HA512H-22P2.
Do you think this can solve my problem:
Thank you for help, regards,
Tom from Berlin



we tried to supply the controler with an external PSU (with max. 5A) but the problem remained the same. I think about if the problem may come from the fact that the stepper is to weak to move the mechanics fast or the controller has malfunction at higher speed.
Any idea? Thx

Alonso Cambronero

I have been suffering from disconnections (the PC plays the USB disconnect sound) whenever my active chiller would kick in. This would also happen if I turned on/off a small fan on my table, or the air extractor on the ceiling.
I have to use a long (2.4 meter) USB extension to plug my laser to the computer.
Yesterday, I decided to connect the laser using a powered USB 2.0 hub and the problem seems to be solved. If the probloem comes back again, I will order the EMI filter.