Thanks @Jules! As always, I appreciate your quick and thoughtful responses.
This very well might be the case. I just didn’t remember the first one having the head in resting position being actually over the honeycomb. I admit that I may be remembering incorrectly, though.
I can assure you that the materials were very flat. I check them before putting them in the machine, use some serious magnets to keep them in place, and then tap test them around to check for anything sticking out. Any bend would not have been enough to justify this type of skewing.
The files are definitely clean and exact. I’m a graphic designer by trade for many a year, so this is one area that I’m confident in. My guess is that the rectangles didn’t show skew because of the normal give inherent in MDF and would have had the same issue had a cut a wider sample.
I’m very happy to hear this. I just hope mine is not the exception. I’ve done lots of work on it and generally it’s amazing. For most projects, though, if something is just slightly off then it’s not noticeable. When exact precision is needed, though, I keep running into things like this.
My fingers are crossed for you. There are so few user-serviceable adjustments, I predict you’ll end up with a replacement. The only things I’ve seen suggested here are to turn off the power and push the gantry all the way back and even on both sides, and to ensure the rails are clean of any debris. If that’s been done and it skips steps or goes out of square on its own, I don’t think they’re going to send you in with a screwdriver.
I’m not sure on that, when it does its calibration the head first moves under the camera to get its world position, then the head moves to the far left and the camera takes a couple pics and it sounds like the steppers move sometimes, I always assumed it was looking at the y gantry and squaring it by moving only one of the steppers. But this is pure speculation…
Oh, you’ve got to try the pins! I used everything from magnets that were so strong I couldn’t lift them off, to Gorilla tape, to practically nailing it down…the only thing so far that has removed both warping and twisting were those pins. I won’t cut without them now. They even keep partially cut up sheets as flat as the topography around here.
I don’t think it does because a) people have solved this problem by manually squaring the gantry, b) support even recommend that sometimes, and c) the motion plan only has one step and direction bit for Y, so to move them independently (which the electronics is capable of) would need some other mechanism.
Also anything the camera does is has not proved accurate enough to detect a small skew in the gantry when each end of it could be 1/4" off.
Not saying that it does it, but seems like one would be able to pick up rotation in the bug. The calibration seems to be right on/repeatable every time for me (in that I can power down and back on, and use old jigs and have perfect runs).
I think if the gantry happens to start square it stays square but it doesn’t actively compensate, so if it starts skewed it stays skewed.
To some extent the wheels will try to pull it square but you can’t rely on that. I have a Shapoko 2 that uses the same axis mechanism and that naturally runs a bit skewed due to the plastic wheels not being perfect. It needs two limit switches and independent Y axis homing to pull it straight. After that both Y axes can step together.
If you are feeling brave you can skew your own axis and see if calibration fixes it by moving the ends independently somehow.
If the source code they released is the same as that which is currently generating the outputs for the steppers (and all indications are that it is), then the Glowforge is not currently capable of driving the Y axis steppers independently.
The code (specifically lines 32-38 for direction, and lines 55-59 for the step) sets both Y stepper motors based only on a single Y step/dir instruction.
Also, the current puls file format they send to the device doesn’t support independent Y-axis direction/steps.
This isn’t to say it can’t be done. It just can’t be done with the existing firmware.
I extracted the logs to investigate the laser arm positioning, and I can confirm that your Glowforge is calibrating properly.
I’m sorry your prints aren’t turning out the way you expect.I have a method you can use to reset your laser arm. All you’ll need are your own two hands and large square layout tool with a foot. You’ll find the instructions here.
Yes if they can ever make the lid camera accurate to 10 thou the machine will meet its specification for accuracy but at this late stage I doubt they will ever get it that accurate. Not having limit switches (and two on Y) is probably their biggest design mistake.
@jaz I gave the squaring thing a try and I think it worked a bit. I recut one of the circles and it hit 3 o’clock before locking up. I only had a 6" square, though, so maybe it wasn’t quite there yet. I’ll keep at it.
