I purchased a Prusa i3 Rework DIY kit, and am experiencing the following final calibration issues. I'm hoping someone here can help me out!
1. I've had a lot of issues with the z-axis not moving high enough up on prints, resulting in the nozzle colliding with layers. I think I have everything fine tuned perfectly now, and should have every mechanical setting in the firmware correct (steps per unit, feedrate), extruder calibrated, voltages set, and am measuring filament diameter regularly - these things improved it greatly. I have had a couple random instances where the z-axis just simply didn't move upwards during print (but did move just fine manually commanded) though that are puzzling to me, and I'm not sure if they were related to the Vref of the steppers. Another puzzle was during extruder calibration, I would command 100 and get 80, then command 100 and get 100. It was very odd, but seems to have somehow worked itself out - I turned off the thermal runaway option in my firmware, as I think that may have been triggering an off command before extrusion was complete.
Anyhow, the nozzle still seems to be dragging somewhat though (but no longer colliding, at least lately) which is predominantly noticeable when it does the honeycomb infill patterns. It sounds aggressively loud to me and like it is scraping; is this normal? Perimeters look and sound fine. Does everybody else's nozzle touch the previous layer?
2. An unfortunate side effect of this is that now my hotend is very loose and will probably cause poor prints, and there are bulges/cracks where the screws hold it in. Every retract command actually jolts the nozzle back about half an inch in the y-direction, and then it returns to center position just in time to start extruding as the gear moves back forward. I had one print earlier with terrible shifting of layers in the x-direction and wasn't sure why, as prints before and after it were lined up great vertically. I'm sure it was related to the loose hotend now. I'm afraid to even drill the screws up to a 4mm size now to tighten up the hotend due to the weakened body and minimal edge distance. Any other ideas? All I can think of is to maybe wrap the hotend in some kapton tape and still use the 3mm screws?
3. Should the fan mounted near my extruder be pointed directly at the hotend, or angled toward the print? I currently have it connected to D9 (motherboard 33), and have to manually start it during prints as I can't figure out how to get it to automatically start. I also have it angled toward the print, as I figured it was for cooling of PLA, but am now thinking it should be pointing directly at the hotend after looking at the prusa i3 rework pictures on the wiki. Any guidance here?
4. Can someone point me to a primer on EEPROM? I can't seem to find much good info on it for someone new to this.
Edited 1 time(s). Last edit at 01/20/2015 07:18PM by Jonny Five.
