by Dr_Radium » 2017-May-Tue-22-May
Moose lake said :" If you aren't going to increase the max z speed then the power off drifting might offset any improvement."
And the power off drifting is brutal. At least it was for me. Granted I am using a modified printhead with a E3D chimera, but there is not a lot of extra weight given everything is aluminum and I built specifically to limit extra weight. we are talking a few extra grams, not a huge amount. If this was the problem, there is no way the Z 4 start lead screw upgrade will work for anyone with significant extra weight at the end of the Y arm. For a unit which is supposed to be user mod friendly, such a thin margin of error for the Z level not holding due to weight seems a poor engineering choice.
In any case, when I would jog up, I would loose from 3-15mm of Z height at the end of the jog due to drifting down. In theory, provided auto leveling is used, the Z stepper motor is supposed to be on all the time while printing, but it isn't. I would have periodic movement failure on the Z arm. This was so bad, I seriously scratched my print bed trying to troubleshoot the drift as suggested by PB tech services. Ended up trying a lot of things including replacing the Z stepper motor and all it did was improve things enough that rather than have the print head crash into my bed, I just had everything print poorly at about 3/4 of the height it was supposed to be. I went back to the 1/4" lead screw wiser if slightly less rich. I was thinking about posting a request for ideas and to see if anyone else had this problem and was able to solve it. Came across this tread doing pre-post searches and figured I should say something here before posting a new thread. If anyone has this upgrade and had similar problems, or if someone with extra weight on the Y arm installed the kit without problems, I 'd like to hear about it. Especially if you had problems and solved it.
Regardless, I'd advise being very cautious about getting this upgrade if you have any increased weight on the Y arm, even a tiny amount.
And if anyone wants to see what I am talking about and what the print results were, I have photos and video available if requested.
Mike