Issue with dimensional accuracy on the z axis

I have a model that is 171.45 mm tall, I printed it out of NylonX and after measuring it came out to 167.85 mm. I'm trying to understand, what could cause this? I'm not sure I've ever had dimensional issues on the z axis. I did recently switch to RatOS v2.1.0-RC2 on my V-Core 3.1 400; I can't imagine that is the issue. Open to ideas.
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5 Replies
CrashTestCharlie / VC4 400h
In Orca, idk about the others, there's a precise Z option. You could reslice using that, then show layer height visualization, see how much difference it makes compared to not using it. 4mm is a lot, but it's the first thing I'd check, as it's fastest Also the holes lined up so it's not a whole part problem. Does the plate to first hole match the cad? Just to be sure the problem is on the Zmax end?
TonyStyles
TonyStylesOP3mo ago
I drilled end holes out. 8 bolts is excessive, 4 will work, so I just made things look visually correct. The holes are 50 mm apart, with one lined up, a second one lines up enough to put a bolt through, but the other two end up way off. I'm using PrusaSlicer. I'll see if I can do what you described when I'm in front of my computer next. Thanks for the help.
Yathani
Yathani3mo ago
Could it be part shrinkage? 2% is within that range
TonyStyles
TonyStylesOP3mo ago
Maybe? Since the print pictured, I did adjust my slicer to account for that; but I haven't tested. Looks like it comes out to just over 2%. I guess I'm not sure what is normal. Was there a range documented somewhere?
Yathani
Yathani3mo ago
I know for ABS/ASA we compensate for shrinkage by increasing of 2%. I would assume its the same thing for Nylon not sure though. Usually shrinkage happens on X and Y but yours printer vertical. Other thing is to check for skew, you might had skew issue before moving to 2.1

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