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aroth

Buildplate moved during print?!

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I started a print of a https://www.youmagine.com/designs/25-item-display-case last night. Checked on it after the first layer was done, and everything looked good (consistent thickness, good adhesion to the buildplate, etc.).

Went to sleep (it's a 30 hour print), and then woke up to this in the morning:

DSC00567 crop

Quite a mess. It looks like at some point, the buildplate forced its way through the retaining clips, and was nearly pushed out of the printer. How does something like this happen?

And more importantly, how do I fix it so it doesn't happen again?

 

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How tight is the glass? It takes quite a bit of force to open and close the clips. I usually have to use a screw driver to get them open. Maybe you can tighten the screws that each hold a clip in place.

 

Yes, it does take a good amount of force to open those clips. I haven't had to resort to using a screwdriver, but I have cut my hand on them when pulling them open.

If I tighten the clips, will that have any impact on my buildplate level? Currently I have it leveled almost perfectly (when it's not being ejected from the printer).

 

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Yes, it does take a good amount of force to open those clips. I haven't had to resort to using a screwdriver, but I have cut my hand on them when pulling them open.

If I tighten the clips, will that have any impact on my buildplate level? Currently I have it leveled almost perfectly (when it's not being ejected from the printer).

 

If it were me, I'd be more concerned with my freaking plate coming off in the middle of the night than whether or not I had to recalibrate the bed ;)

 

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Yes.

Though without working out how it happened, it may be the case that tightening the clips won't fix the problem and could introduce a second (though much smaller) one.

Based upon the photo and the geometries involved, it seems like the glass plate would have first had to have been displaced laterally towards the left of the printer before being pushed forwards towards the front. Otherwise it would be pushing straight into the screw that holds the clip in place, which should stop it from moving forward no matter how tight/loose the clip is?

 

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I had a case once that a huge blob of XT formed around the nozzle and the heating block. I had to remove everything and clean the entire head. What a mess.

The head could have stick to the model and pushed the plate out of the way because it was sticking so well.

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could it be that the extruder seriously dug into the already printed plastic and had enough force to push the plate out of position, popping the clips open? could be a problem with your z-axis? or plate height?

 

I think it was probably the first scenario. The part that was printing appears to have lost adhesion with the buildplate in the rear-right corner (when facing the printer head-on). It was curled up a fair bit, and there's a mark on the print in that area that looks like it could have been caused by the nozzle ramming into the curled-up portion of the part. So:

 

  1. Bottom layer stops sticking to the buildplate and curls upwards and inwards.

  2. Eventually it curls enough that there's space for the nozzle to slip off the far side of the print.

  3. The nozzle slips off the print on its way out, and the part curls back upwards behind it.

  4. The printhead reverses direction, as it tends to do, and gets caught on the print on the way back (probably traveling at a 45 degree angle across the buildplate).

And then it's just a question of the friction between the rest of the print and the glass versus the friction between the retaining clips and the glass. One or the other wins, and then something comes loose.

I wonder if it would be hard to update the printer's firmware so that the motors stop if they encounter an unexpectedly high amount of resistance? As opposed to pushing against it and possibly damaging the buildplate, the printer, or whatever happened to get into the way of the printhead.

 

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