Kind Regards.

In regards to overheating, we see this as more of an intermittent problem than a constant chronic problem. To be honest we've never seen much of it in the shop. We may add a spot on the FAQ about it, but it hasn't come up in a very long time.

It's problem that affects ALL prints for me that take longer than 1 hour.  It's an intermittent problem for prints that take 10 minutes or so.

Meaning that it jumps several times an hour and sometimes I get lucky on short prints.

The fan fixed that, but you have still never replied to my email regarding the rear bar tight in the bushings.

The other problem is that the bushings in the back for the y axle are being pulled two different directions, and it's just a tight fit in general.  They also never responded to my email about it.

I would check to make sure your head moves freely with the power off, if it feels too tight that can cause the jumping as well.

I had to take mine apart and sand down the y axle ends with emery cloth to reduce their size every so slightly.  I still haven't replaced these bushings with bearings, but I plan to at some point.

Successive layers shift in the X or Y direction during a print

This can be caused by a few things:
The filament spool doesn't rotate freely during a print, putting too much force on the motors.
The part is too large for the build surface and/or improperly positioned. In this case the extruder may bump into the end of the axis during a print, causing the layers to shift over.
The flow rate is too high, causing blobs of plastic to build up on the part, eventually causing the extruder to get caught.
An improperly set trimpot on a Stepper Motor Driver. The trimpot, which control motor current, could be set too high or too low. The four stepper motor drivers (X, Y, Z and E) are located on the motherboard and can be adjusted with a small screwdriver. This is a tricky problem to diagnose, so we recommend you contact us first so we can walk you through it. Here are some general guidelines: If the current is too low there may be no indication except layers shifting in the X or Y direction. If the current is too high: in addition to layer shift you you may notice an slow, audible click when the printer is powered up and the motors are enabled but not moving. Gently turn the trimpot clockwise to increase current or counterclockwise to decrease current.

I had to make this adjustment for my z axis because of the same problem you are having. It was debatable if cooling the board or adjusting the trimpot solved the problem. You can also measure the overall height of your print compared to what it is supposed to be. If it is too short, it is likely you are having some sort of overheating issue.

This is what I am printing: 'http://www.thingiverse.com/thing:4155'.  It printed fine all the way to that top cube like structure at the top.  Then it started to print that, and I noticed, about half way through printing it, that the nozzle was dragging through the plastic (of the layer before the one being printed).  Now, I suppose that means the nozzle is too close to the platform, but it printed fine up to that point... although here it was printing solid lines for all the layers, so there was a lot more plastic.

What do you think, should raising the nozzle a bit (via the z screw) help here?  Otherwise it seems to print really well.  The first layer sticks really well and the corners don't curl, so I am somewhat hesitant to break that.

Dan

Dan

mine jump only with a certain type of model .. so i think it depend of the speed movement..

thanks
dan