Layer Height and Total Z Distance

[printguy 0]

I want to print a 20x20x20 cube. .28 initial layer, .2 layer height. X & Y are perfect but, Cura always gives me ;MAXZ:19.88 and my cube ends up short at 19.88.

Using .28 initial layer and .16 layer height I get MAXZ:19.96.

Is this standard and will I have to adjust my layer height to get the correct Z height on every part?

[GregValiant 1,276]

Cura won't slice when it runs out of part.  99 layers at .20 + 1 layer at .28 = 20.08.  There is no part there to slice and so your block is short by 1 layer from the 20.08 theoretical height number.  (what a coincidence ~ 20.08 - .20 = 19.88).

 

You can adjust the Initial Layer Height (in this case a .2 initial layer works perfect), or use a layer height that is an exact divisor of the "part height - initial layer height".

So if you want to keep your .28 Initial Layer Height then 20-0.28 = 19.72 and that will be the other 99 layers at .199 layer height.  99*.199 = 19.7 + .28 = 19.98.  You would want the Initial Layer Height to be .30.

 

If there is an intermediate surface that is at say 15.25 from the bottom, you can see that it won't come out exact on a model that uses the numbers above.