Elegoo Mars 2 Pro Calibration XY and Z

[cliffyk]

I have never, with my plain ol' Mars, experienced height deviations of that magnitude..

I left this message at the fellow's site:

Have you experimented with exposure times as well?

I ask because fundamentally we are building object by creating mushy tiny little, partially cured 0.05 x 0.05 x (selected layer thickness) mm “bricks” of partially cured photo sensitive polymer resin (curing has been initiated but is not complete, hence the need for additional “post-process” curing) . The machine produces these bricks from beneath the final product and then alternately compresses and stretches them during the remainder of the print job.

That it works at all is somewhat of a wonder. It seems intuitive to me (and intuition is often incorrect) that some optimal initial exposure would render those “bricks” as dimensionally stable as is possible–which would have t produce a better dimensioned object.

As i have stated here in a number of threads now, to me the weak links in this technology are the "mushy little bricks" we are sticking together--which on my Mars can be no smaller than 0.0469 x 0.0472 x 0.01 mm (I have never printed with 10 micron layers--not sure I'd live long enough); also I f we assume these mushy little bricks are inherently dimensionally flawed, and that in such processes flaws tend to be consistent in their vector (I.e. not random, but rather either under- or over- sized by some magnitude), all adding layers does is magnify the error.

Stack up 10 "2 inch" thick bricks that are really 1-3/4" and you'll have a 17.5' stack--2.5" short; stack up 20 "1 inch" bricks that are really 3/4" and the stack will be 15"--5.0" short.

[mrmarsmensch]

"
And now we came to my problem...
I have a simple part like a round gear for simplest without tooths.. like a flat wheel diameter 45mm with only a thickness or z-Height of 3,1mm.
On this flat wheel i have a cylinder with diameter 16mm and z-height of 8,5mm.

And now erverbody can draw it and export it and print it - it is very simple part.
If i print it with default factory settings i have a thickness or z-height of the flatwheel of 3,08 to 3,12mm - looks not so bad but the z-height of the cylinder is not 8,5mm is only 8,07 to 8,09.

And if you make a 6mm diameter hole in the middle on the cylinder with a depth of 2,5mm it has exact 2,5mm depth.. so this is so confusing...

I have a picture of this simple part - i can also upload the stl - but the jumping point is - make your own and print it with your Elegoo Mars 2 Pro and give me your results... tell me you can print 8,5mm height cylinder on a flatwheel with 3,1mm height with a hole of 2,5mm depth or minus z-Height.

For me it looks like there are some bugs in calculations - chitubox slice the layer on 0,05mm layer-height only 0,043 and 0,083 and then 0,122mm and so on - i dont understand why this happen.

All calibrating-ideas are useless then if i start to calibrate M8010 then the hole of 2,5mm depth goes also deeper... maybe 2,6-2,7mm dependig from my changes --- thats frustating.
If i use the M8084 only the flatwheel on the bottom is affected."

I have had the same problem for the past Week. I tried so many things.

My test object was a 10mmx14mmx20mm(z) cube with a horizontal half-cylindrical hole with a radius of 4mm. (Pictures)
But the whole cube came out exacty 10,00mmx14,00mm but the height was only 19,6mm.

I am using chitubox V1.9.1 with the correct firmware of my elegoo mars 2 pro

I have tried different setting:

layer height= 0,01mm or 0,02mm
curing time = 1,6 - 2,5 seconds
first layer curing time = 28s
first layers = 5
first layer x/y compensation (new tool) = -0,24 mm

I am using the Elegoo standard photopolymere Resin
but i mix that with 20% of Monocure FLEX100.

No matter what I did the object always came out wrong.
for example with settings:
curing time = 1.6s
layer height = 0,01mm
...the object came out: size a = 3,7 and size b = m15,7

instead of the a = 4 and b = 16 what I wanted.

So my whole Z axis is sort of scaled down by a few % and even if I tried to compensate that by using a elliptical instead of a circular hole the result somehow came out even worse the hole was still "squished" on the Z scale. I also scaled the whole object in the Z axis to 20,4 mm and the printed object then was perfectly 20 mm high but the hole in it still was too small in the Z scale.....?

Has anybody a solution for that?