Why is z height off by so much

[engr 1]

I am printing a bracket (shaped like a wide V or sort of batwing), dimensions about 7 inches long and .75 inches high (180 mm x 19 mm). Using Ultimaker PLA with Ultimaker PVA support with 0.1mm layer height using (latest Cura and UM3+.

The final print is only .69 inches (17.5 mm) instead of .75 inches, so the Z is off by a lot. I measured before dissolving the support, so it's not warping.

I can't show the whole part because it's a corporate design, but here are some images which I think show enough.

The only idea I have is PVA shrinkage during print (maybe water content, material pops a little during print, but doesn't seem soft or sticky and it adheres fine)

Any suggestions what is the cause? Thanks.

[fbrc8-erin 181]

Is your active leveling on? Is the wrong height the same all the way across the print?

 

Active leveling makes corrections through the first 20mm of Z-height (if I remember correctly), so if your bed isn't manually leveled well enough, you could end up with it the height being wrong on one end or the other.

[SandervG 1,135]

What about the X and Y dimensions, are they correct or off as well?

[engr 1]

7 hours ago, SandervG said:

What about the X and Y dimensions, are they correct or off as well?

X & Y dimensions are as good as usual (within .010").

[engr 1]

14 hours ago, fbrc8-erin said:

Is your active leveling on? Is the wrong height the same all the way across the print?

 

Active leveling makes corrections through the first 20mm of Z-height (if I remember correctly), so if your bed isn't manually leveled well enough, you could end up with it the height being wrong on one end or the other.

Active leveling is on. The part is shaped like this when printed:
¯\__/¯
And the dimensional discrepancy is between the build plate and the ends on both ends. So, yes, it's the wrong height at both ends of the part.