Laser gantry derailed during passthrough print

We have again run in to a problem like stated before on the forum. That is that during the passthrough print the laser arm derails itself during the line up proces.

This is now the third time this has happend. There is nothing elevated there is no debris on the sides I did not bump into anything and everything is clean belts are tight etc.

What I did notice is that the arm moves really fast to where to take the picture for the line up. And that is when it miss align its self. Than it moves back really quick and bumps and aligns itself again because of the speed I guess.

After that happend I re tried the allignment and than it did not derail but pusses the alignment about 1 inch lower than where it should be. This happend printing a giraffe I could not finish.

Why does the laser sometimes move so fast and other times really slower ?

Maybe my English is not 100 ok that is because I am dutch so you know.

This is my third machine and when it working ok I really like the machine but this has taken so much of my time and money and material that I seriously like stated before and before apricate to be compensated for al my trouble and this time for real !

And have the decency the respond to the request because gf always ignore this.

In the attachment is a film where you see that the same thing happend like stated above.

But here i thought maybe the inch lower alignment was only on the screen an maybe it was aligned in the machine. But as you can see it wants to go the inch lower like on the screen.

My guess the stepper motor is not ok. I have been making lots more passthrough prints whit previous gf and never had this problem this machine is not ok.

Also when moving the laser arm when its turn of it isn’t a smooth ride.

I would appreciate a solution as soon as possible.

this was send by email and have had no response!

Thank you for your effort !!

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There is something you need to check.

1. Turn off the machine.

2. Lower the front door, use a flashlight and get down so that you can see underneath the gantry on the left side.

There is a red cable that runs the length of the gantry, you can see it through the tube if it is clean…locate that cable, keep your eyes on it and slowly push the gantry back to the rear. If you see the cable catch on the fins of the heat sink or feel any resistance, stop.


If you see that happening, you can CAREFULLY adjust that cable following the instructions at the link below.


Hi Jules, thank you for the response!
The red cable does hit the heat sink. But I am doubting this is the issue. Because it derailed when moving forward and than it’s not obstructed bij the red cable.
Does that make sense !?

If the red cable hits the heat sink it most definitely is part of the issue. That cable catches on the heat sink and bounces the gantry forward, causing it to jump the track on the right side. And it can damage that high voltage cable if you keep trying to use the machine without shifting the cable back into the correct position.

This only happens on Pro model machines, and it usually happens because at some point the head got pulled too far forward and that shifted the cable in the first place.

  1. Turn the machine OFF and UNPLUG IT before slowly easing the cable to the right to take up the slack.

  2. You will gently pull that cable from the RIGHT side of the laser arm, to ease it through the channel underneath the glass tube.

  3. It will hopefully resolve the problem. And when you clean the machine, be careful not to pull the head too far forward…it needs to stay over the gridded area of the tray, which is as far as it can normally reach.

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Thanks Jules! I hope that your Wright about this. I moved the red kord to the right side and will try some pass trough cuts this week.
Why does it only happen during the line up proces?

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It happens when the head moves to the Home position at a higher speed. (Inertia, I guess.)

It’s not an issue unless that cable has enough slack in it to catch on the heat sink.

So we take the slack out. No more problem.

I always love it when someone from another country whose native language does a masterful job such as you describing their issues. I hope they can get this sorted. @jules is one of the best troubleshoots among forum regulars.

Just so you know, as soon as the pandemic fades and I can resume international travel, the Netherlands is first on the list to visit. The Dutch on this forum have always been super in their contributions!


Unfortunately, it looks like your unit is experiencing an issue that we can’t resolve remotely. I want you to have a reliable unit, so I’m recommending we replace this one. I’ll be in touch via email to sort out the details. I’m so sorry about the bad news.