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So on 3 occasions, always while I have stepped out, my rostock loses position and then knocks the print out the build platform. I can see evidence of the side of nozzle hitting and meting the plastic near the top edge. I am running slow speeds 30 mm/s print/infill 150 mm/sec travel. No evidence of warping or lifting. What could cause this? I haven't seen it happen cuz I don't have the luxury of sitting and watching my prints Anyone encounter a similar problem?

Short version is no I haven't seen it happen.
Does it always happen at a similar height above the bed?
It could just be poor adhesion to the bed.
It could be you're losing steps on one axis, or have a lose gear on a stepper, what this does is tilt the plane of the print.
You really need to see it happen.

I was going to add that I am running off the SD card. It has happened on different prints at different heights. I don't think it's an adhesion problem because I haven't seen any curling or lifting yet.

But I will run the last print again and watch it, see if it happens the same way twice. I guess I have my weekend planned

Polygonhell wrote:Short version is no I haven't seen it happen.
Does it always happen at a similar height above the bed?
It could just be poor adhesion to the bed.
It could be you're losing steps on one axis, or have a lose gear on a stepper, what this does is tilt the plane of the print.
You really need to see it happen.

Where can we purchase new gears at? I think mine are failing. Can you include site and part # please?

Check your belt tension and motor timing pulleys. Belts have to be tight! Motor pulleys could be getting stripped.

elqisqeyano wrote:

Polygonhell wrote:Short version is no I haven't seen it happen.
Does it always happen at a similar height above the bed?
It could just be poor adhesion to the bed.
It could be you're losing steps on one axis, or have a lose gear on a stepper, what this does is tilt the plane of the print.
You really need to see it happen.

Where can we purchase new gears at? I think mine are failing. Can you include site and part # please?

Seemecnc sells them, they are they are the newer 20 tooth gears that they are now shipping.
Under accessories, belts and pulleys, 3 for $20

Eaglezsoar wrote:

elqisqeyano wrote:

Polygonhell wrote:Short version is no I haven't seen it happen.
Does it always happen at a similar height above the bed?
It could just be poor adhesion to the bed.
It could be you're losing steps on one axis, or have a lose gear on a stepper, what this does is tilt the plane of the print.
You really need to see it happen.

Where can we purchase new gears at? I think mine are failing. Can you include site and part # please?

Seemecnc sells them, they are they are the newer 20 tooth gears that they are now shipping.
Under accessories, belts and pulleys, 3 for $20

thanks

My gut instinct tells me to go for the technical advice; however, I've got to ask:

Do you have a cat?

Hahaha, that is funny. I wish it were that easy. No cats.
I stripping down the arms for more sanding and checking the belts and pullies.