[laserchick87]

Hey all (again)....

After my company bought a laser cutter from China 10 months ago, would you believe it.... I still can't get it going. After being a newbie to lasering, after 10 months of fixing it and trying to get it going, I'm learning more than enough! More than I should know about lasers to begin with before even being able to use it properly! We even had one of their technicians from China come out 2 months ago and not even he could fix my laser in the week he was here. Now it's back to email communication and them trying to figure out (still) what is wrong with it. We are getting no where and they are asking me to do the same things over and over again, but none of what they are telling me to do is the problem (no matter how many times I try). The problems are completely random, which make no logical sense.

Anyway.... to the problem. I have one main problem at the moment, which not even China can diagnose (from another continent). The cutting head randomly comes crashing down into the sheet on the bed (not softly either)... It dives straight down makes a huge dent in the sheet. It happens sometimes when it's not cutting, sometimes when it is about to cut, sometimes just after it pierces the sheet, and other times, in the middle of cutting. Completely randomised, which gives no hints as to what the cause is.

I have tested the height sensor on the nozzle. It appears to be working. The "z control" drive has no errors. The "z control" box has been completely changed and the wiring changed. I have changed nozzles, adjusted the laser path a million times, cut at different heights (from 1mm - 3mm above the sheet).... yet nothing stops it from violently crashing at random, which can't be doing the head unit any favours.

I can cut one part perfectly, and then as soon as I start the next one, it will crash. Again, completely random.

Sometimes when the head doesn't crash, the head won't retract when traversing between pierces. When I test the height before cutting when it does this, you can see the motor trying to retract the head, but happens incredibly slowly... maybe a few mm a minute. So to get back to the normal height it should retract to, it could take 5 minutes.

To me, with the random crashing and the random head not retracting, I think it could have something to do with the motor being jammed or faulty. If it gets stuck retracting it, what's stopping it from letting the head go altogether to make it crash??? That's my theory... Or - there's faulty wiring somewhere in the system.

Anyone have any ideas that could help me? I've run out of options and would love some advice!! Getting no where with the email correspondence with Chinese company. I seriously think they have no idea what is wrong, and they wont send anyone else out.

Anyone on here got any thoughts or suggestions? Or who may know what the problem could be? Would be much appreciated!!

Thanks

[Ch_Irawan]

What kind of laser machine is that CO2, YAG, or Fiber?

I interested to see the pictures of the problematic laser head and controller.

-ichan

[18111]

Something might be loose. Have you checked all screws are tight and belt tensions are correct?
I don't have a laser yet but it's my thought.

[grawley]

Could be one of a number of different problems.

1. Re-seat your cables.
2. On the Z axis driver, check the grounding wire. Make sure that it is grounded to earth ground. Using your multimeter, set to AC voltage and measure between the machine and earth ground (it may not be grounded properly and show a changing AC voltage). You can read the manual from the manufacturer of the Z axis motor and driver and they will discuss grounding and AC line interference and various strategies to deal with or prevent problems.
3. If 1&2 do not work then you may have an AC interference problem with your Z axis encoder line. In other words, the AC line is disrupting the servo motor control signal line. Try separating the encoder wire (that goes from the driver to the motor encoder) from the AC lines. Check the control box. You can put a piece of sheet metal between the AC power line and the encoder wire to test. If this solves it, then change your AC line from wires to a shielded AC power line to the Z axis driver. I had this same issue where the homing would home in a different place every time. After grabbing a piece of sheet metal off the shelf and sticking it between the AC line and the encoder line then there was no problem. Adding the shielded AC cable and re-routing the AC lines solved the issue.

[laserchick87]

What kind of laser machine is that CO2, YAG, or Fiber?

I interested to see the pictures of the problematic laser head and controller.

-ichan

We have it on CO2 at the moment. Model is a Perfect Laser.

I can get photos if you like?

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[laserchick87]

Something might be loose. Have you checked all screws are tight and belt tensions are correct?
I don't have a laser yet but it's my thought.

Myself and China have checked all the wiring visually and with a multimeter...

I'll check again. Thanks!

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[laserchick87]

Could be one of a number of different problems.

1. Re-seat your cables.
2. On the Z axis driver, check the grounding wire. Make sure that it is grounded to earth ground. Using your multimeter, set to AC voltage and measure between the machine and earth ground (it may not be grounded properly and show a changing AC voltage). You can read the manual from the manufacturer of the Z axis motor and driver and they will discuss grounding and AC line interference and various strategies to deal with or prevent problems.
3. If 1&2 do not work then you may have an AC interference problem with your Z axis encoder line. In other words, the AC line is disrupting the servo motor control signal line. Try separating the encoder wire (that goes from the driver to the motor encoder) from the AC lines. Check the control box. You can put a piece of sheet metal between the AC power line and the encoder wire to test. If this solves it, then change your AC line from wires to a shielded AC power line to the Z axis driver. I had this same issue where the homing would home in a different place every time. After grabbing a piece of sheet metal off the shelf and sticking it between the AC line and the encoder line then there was no problem. Adding the shielded AC cable and re-routing the AC lines solved the issue.

Interesting points!!

I'll have a look at the manual and see where those lines are and give it a go!

Thanks heaps! It does seem like there is an interference somewhere

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