Print Glass and all pushed off printer

[enchantedsord]

Hello everyone!

Well I have had my machine up and running since december and when printing small parts for the most part I have no issues and it looks good, but I have recently tried to print a part that about 8 inches square and up to about 4 inches high or so and somewhere between 12-24 hours into the 35 hour print it seems to catch somewhere and it has slid the entire glass piece and all off the printer. I have tried it in mattercontrol and cura and cura was able to get the furthest in the print ruffly 24 hours but both times the glass print and all was pushed off. Kinda scarey.

Luckily no damage but I can't seem to figure out the issue. I'm using the .35 nozzle and it seems like once it gets higher the nozzle is dragging and I think what is happening is it finally catches and gets stuck then pushes the part.

Any idea how I might go about correcting this? I have added some additional z hop but it seems like it's happening when it moves within the same layer and there is no z hop. Could it be over extruding, filament temp?

Anyway maybe I need to try some more calibration. What do you generally recommend besides the paper under the tip thing.

When I print smaller parts it doesn't seem to be an issue but I do definitely see drag over parts of the same layer when it crosses.

thanks
Larry

[Mac The Knife]

The diagonal of an 8 inch square, by my calculator, is 287.36 mm. That's a little ambitious, considering the print area is advertised at 280mm and that is pretty optimistic in itself. What speed are you printing at?

[enchantedsord]

I have it printing pretty slow and it printed out 1inch then it kicked it and plate off. I have it set to the following...

30 mm/s infill
30 mm/s inside perimeters
30 mm/s outside Perimeter
40 mm/s Support mat (no supports in this print though)
60 mm/s bridges (no bridges)
150mm/s non print moves
12mm/s First Layer

If it matters any this is what I was printing. I tried both trays and had the same issues with both at different heights.


http://www.thingiverse.com/thing:176679

[Polygonhell]

Most likely you are over extruding, eventually the build up of plastic is enough to catch the nozzle.
The nozzle should drag through the existing plastic.

print a single wall test piece and measure your extrusion width this is a piece I wrote on it a while back http://forum.seemecnc.com/viewtopic.php?f=54&t=1163

[bot]

I'm with Mac the knife on this one. Given the information you provided, I can only assume that you have very poor, if any, adhesion on the areas that extend way beyond the build volume of the printer. They will curl up, your nozzle will hit them and apparently move the glass. Do you have the glass clamped down? I've never had that happen personally.

[enchantedsord]

Yeah it's clamped down with 6 clips. I checked the adhesion but it was really good and took a bit to get the print off . I'm thinking over extrusion also. I'll try his print and sees what I get.

[hugepanic]

check the Z-lift!

I had issues with it on my larger prints. No i have a Z-lift of about 1.3 or 1.5mm and no problems.

see http://forum.seemecnc.com/viewtopic.php?f=62&t=7509

If you have no z-lift, the nozzle might catch a structure when moving fast. This is especially true wenn you get cracks in your parts. At one point the part cracks and the height of the residual part is higher than the nozzle. So when the printer moves, the nozzle will rip the part in half or from the plate.

[TFMike]

This had to be done with ABS right? Have you thought about trying a different material?

[Eaglezsoar]

Did you calibrate your cold extruder according to the manual?

[3D-Print]

This happened to me although I didn't catch hard enough to drive the glass off the printer. I found my X-axis belt adjuster slipped (didn't tighten it "Dan tight" as my kids call it) and the X-axis belt had too much slack. After 3 failed prints I watched until it happened. When the X-axis was at it lowest point and the print head was near the Z-axis the fail occurred when the X-axis began to raise and the Z-axis drop. When the print head changed directions the slack in the X-axis belt resulted in a slight delay in movement that in combination of the Z-axis downward movement resulted in the print head hitting the print so hard that the head jumped 3-4 inches away from the print line and gouged the printed surface.

I readjusted the tension on my belts and the problem resolved. I've printed some belt tensioners to keep them stable and tight. Installing them this weekend.

Dan
...............

[Eaglezsoar]

This happened to me although I didn't catch hard enough to drive the glass off the printer. I found my X-axis belt adjuster slipped (didn't tighten it "Dan tight" as my kids call it) and the X-axis belt had too much slack. After 3 failed prints I watched until it happened. When the X-axis was at it lowest point and the print head was near the Z-axis the fail occurred when the X-axis began to raise and the Z-axis drop. When the print head changed directions the slack in the X-axis belt resulted in a slight delay in movement that in combination of the Z-axis downward movement resulted in the print head hitting the print so hard that the head jumped 3-4 inches away from the print line and gouged the printed surface.

I readjusted the tension on my belts and the problem resolved. I've printed some belt tensioners to keep them stable and tight. Installing them this weekend.

Dan
...............

Dan, which belt tensioners did you decide to use?

[enchantedsord]

I would love to find out also.

[3D-Print]

Here is a link to the thread and files which "KAS" posted (http://forum.seemecnc.com/viewtopic.php ... 5&start=96)

Hope it helps!!

Dan

[Eaglezsoar]

Here is a link to the thread and files which "KAS" posted (http://forum.seemecnc.com/viewtopic.php ... 5&start=96)

Hope it helps!!

Dan

Thanks Dan, those look like they are strong and should work fine!

[3D-Print]

As well, I have wondered if there is a more accurate way to adjust the tension. I my "build thread" we have talked about a few ideas to do this but not sure how precise this really needs to be though (http://forum.seemecnc.com/viewtopic.php ... &start=104).

I can envision you could have trouble with loose belts if you are trying to printing a 0.2 mm thick layer whereas if your layer was 0.3 mm or 0.4 mm you would have no problems with drag or catching the hotend on the print. Moving the print glass or as with my problem is the extreme example of a loose belt.

[3D-Print]

I agree, I printed them with a 90% infill. The main concern I had was with the strength of the tension "tabs." I printed one of each then "cranked on them" with a pair of pliers and they are quite strong.