Lightobject.com Support Forum

Hi Marco,

As you know, I'm developing a model ship kit and have been cutting out billets of parts with the 80 watt reci laser I built. A few times I've run into some erratic cutting that happens every once in a while and is unpredictable when it will happen next.

Here is a photo of some parts I cut out.
The parts were cut from the same file on both billets. The lower billet was cut last week. The upper billet was cut today. As you can see the parts in the upper billet are all messed up. As a matter of fact, that last part on the right hand side didn't finish. The laser suddenly started cutting erratically and then it just stopped cutting and shut off with the axis not moving. I had to actually turn the machine off to get it to reset.

What is causing this? Is it a bug in the controller or something else? Has anyone else encountered this sort of erratic cutting behavior? I put an AC filter into the incoming AC line to filter out noise.

The most recent modification I've done to the machine was to add a second exhaust fan. The second fan is attached to the left upper side of the machine near the cutting table as shown in this photo:
I currently have this exhaust fan plugged into an extension cord drawing the 110 volts AC directly from the wall socket. The other fan is in the back and it is a 12 volt fan drawing power from a 12 volt power supply inside the machine. Here's a photo of the complete machine:
Any help you can give me or anyone else can give me would be greatly appreciated.

Thanks,

Bob

It shouldn't be bug on the DSP. It seems like that there was some "interference". Make sure the "PWM" or "TTL" control wires on the DSP card stay away from the "HV", the high voltage cable. You may do some test on paper with lower power and check whether the issue happened to the exact location. If it does, it could be the graphics file issue.

Use lower power and test again. What we need to do is trying to eliminate parts that are not subject to the issue. If problem keep happening, the most possible suspect I'll think of is the laser power supply.

You may send me the files and let me test


Marco

Hi Marco,

I just sent the file to you. I don't think it is the file because I've cut the parts several times from the file after the problem occurred by turning the machine off and back on again. I'll check the wires but I don't think thats the problem because I've done 17 different files that cut perfectly after the problem occurred and this morning I did some etching and that went fine.

It appears to happen if I've done some firing of the laser to align mirrors and then try to cut something without turning the machine off and back on.

Thanks,

Bob

Could be static built-up somewhere in the machine and caused the issue. Or, it could be hardware issue like bad power supply or DSP card(less likely chance). Follow my email to check proper grounding first. Then we moved to next step

Marco

Nope, it's none of that Marco, I've checked and double checked. Yesterday I simply turned the machine on, uploaded a file and started cutting. I cut 6 files, no problem. Then I test fired the laser a few times, loaded a new file, started cutting, and the erratic cutting happened. I'm sure it's related to the firing of the laser prior to loading a file and cutting. Why, I don't know, but it's easy to work around. Simply turn the machine off and back on after doing any test firing of the laser and it works just fine without any problems at all.

Thanks,

Bob