I’ve had my Vertex up and running for a couple of weeks now, and apart from a few initial problems with X/Y shifts which turned out to be from excessive belt tension, it’s working really well and I’m very happy with the quality of prints. I have a minor issue with one part of my build plate which is too low but I have a new alu plate on the way from Velleman (thanks again for the great support) which will hopefully fix that.
The one remaining problem I have is really intermittent. Every now and then the print bed will move too far down during a print (by sometimes 1cm or so) so that the print head is printing in mid-air. It has only happened maybe 3 times in total and there doesn’t seem to be a pattern of it happening at a particular Z height. My Z axis has always been quite noisy and felt rough even when assembling, but it seems to move well enough. I did install the Z axis stabiliser mod because I had a lot of noise and vibration from the loose end of the threaded rod. I’ve made sure the rods and the threaded rod are well lubricated. Does anyone have any suggestions for what could be the cause?
Are you certain it’s z-axis shift and not simply a blocked nozzle that restarts to print after a few minutes? That can give the same impression - i.e. mid-air printing.
Hmm, good question. I’d have to watch it exactly when it happens to be sure, if I could get it to happen consistently I could film a print to check. From the way the filament was being extruded after the ‘skip’ it didn’t look as though it had missed out part of the print, but again I can’t be absolutely 100% sure. I haven’t had any problems with nozzle clogging or blockage so far though.
I’ll have to set up something to record a few prints to try to get to the bottom of it. It’s probably worth disassembling the Z stage to see if I can get it any smoother as well as it has always been quite rough and scratchy even before connecting it to the motor. I’m not sure what else I can try with it other than perhaps to replace the linear bearings. The bearings themselves seem to slide smoothly but as soon as I mount the bearing clamps it all gets noisy and stiff, I wonder if there is a bit of play in the bearings which allows them to bind as soon as there is any additional weight on them.