Mechanical Crash

Prior to the mechanical crash described below, there was a misalignment printed job. The design was placed using the GFUI at the extreme front edge of the 1/8 inch material. It showed Score and cut operations normally on the GFUI. When I clicked on Print, there was a delay in getting a completion of the time to process, so I walked to the next room where the Glowforge is located. The White light was blinking normally indication ready to process. I press the button and noted the design was misaligned from the GFUI: it was about ½ inch forward of where the GFUI showed it. This meant that part of the job missed the wood edge.

After this finished, I moved the position of the job on the GFUI to the right repositioning the job for a second cut attempt. This time I waited for the user interface to present the time for the job, 1:15, and walked to the machine to press the white light button.
The mechanical crash then happened.

After but close to 7:40PM Eastern time my Glowforge head crashed into the front-left side of the external frame. I raised the lid immediately cancelling the job. The gantry was cattywampus with right side at least an inch forward from the left side where laser head was stopped. Yikes!

Turned off power and tried to align the gantry by moving right side to apparently align with left side.

Machine was then powered up and did its normal invocation protocol. It then correctly processed the job with alignment agreeing with the GFUI image.

Question: Does the invocation protocol, when power is turned on and head is centered and then is homed, align the left and right positions of the gantry?

What could have caused this crash when the white light was blinking before starting the job?

The carriage arm wheels could have encountered debris on one of the rails or there could have been a piece of material extending into the wheel path. When the machine is turned off and back on, it goes through the centering and homing process and the software locates the printhead in its proper/current position.


In my case this could have required different number of y-movement steps for left belt from right belt, unless I was just lucky and my eye-balled alignment was correct. Just glad it seems to be working.

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With the machine turned all the way off, you need to push the gantry all the way to align against the back wall. If you do not do that it will stay misaligned. then you need to understand why it got misaligned in the first place moving the gantry forward and back feeling for the resistance. If in moving forward the head hit something over a half inch tall (like a pin) that could do it as well so you want to make sure that nothing like that is happening also.

As soon as anything moves the head not done by the machine it will be always off until you align the gantry to the back wall and let it go through the starting routine.

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Thank you. Will do.
Hold-down pins were used so nothing was close to 1/2 inch tall. The initial misalignment where the work was cut about 1/2 inch more forward than showed on the GFUI is a puzzle.

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I figure the answer is no, as you probably would have realized that pretty quickly, but …

Were you using oversized materials that hung off the edge of the tray? You don’t have much room on the edges before the vertical gantry supports will hit it. Long shot, but I’ve had that happen to me before.

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Material was 12 X 18 inches positioned with front edge exposing 1/2 inch y-direction of honeycomb tray. Other cuts went OK with this piece in same position.
Somehow the system lost it’s location between finishing one job, opening lid, and trying another repeat of job. First time it has happened to me.
This is a robust machine! It is performing well since the realignment.

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I sometimes get a confused Glowforge if I start the machine up with previously-cut materials on the bed. I think it interprets dark rectangular areas as “oh that looks like the print head” and things go really wrong.

Glad you got it sorted!


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