Prints being scaled up by Mars 2

[elegoop]

Hello, I've recently purchased the mars 2. Coming from my old printers the quality on this thing is stunning. And the speed. But for some reason my prints are being scaled up. When using chitubox, the measure approx 69mm (just under 2-3/4"). This is the correct diameter, and matches what I have printed before on other printers. But when I start printing, the part comes out over 3" diameter (about 78mm). The files are the same I've used in the past. In chitubox and in Cura they show the same dimensions. But when I print, they're much bigger. I can probably work out specifically how much bigger they are and scale my print down accordingly, but it sure would be easier if I could just enter the dimensions and have the part come out reasonably close. 

Anyone have a similar issue? Any ideas?

[cliffyk]

Are you 100% certain you are using the proper printer configuration in the slicing applications?


I ask because the resolution of the plain il' MARS is 2560 x 1440 (X, Y); and the MARS 2 is 2560 x 1620. 

• 1620/1440 = 1.125;
  
• 1.125 * 69 = 77.62 (or, "about 78");
  

I do not know why they would grow evenly in all axes  X, Y and Z as you have described (you cite an increase in "diameter" implying such)--however it is curious that the increase proportion is the same as the Y-axis ratios.

Did you re-slice the .stl files, or are you literally attempting to print the same sliced (.ctb) files?  If the latter that may somehow explain what you are observing--though that the increase in in all axes is still baffling?

[elegoop]

I think you nailed it. When I first set up the machine and tried to print something it threw a 1440 error and would not let me print. I looked up the settings for the mars, and changed it to the 1620, resliced, and then the part came out 1.125% bigger than expected, (and although I didn't realize it at the time, it was Only on the xy). 

I measured the oversized print yesterday, and it came out to 8% bigger. So I scaled the entire print down 8%, and although the x/y came out perfect, the z came out at (no surprise now...) 8% under. 

So if I just scale down x/y only, my print should work fine. I'm going to try it when I go home for lunch. In the meantime, is there a more obvious solution then scaling down the x/y? Is there a way to tell it to print to the 1440 without it throwing an error? 

Thanks for your reply, it's very helpful.

[cliffyk]

Did you go back to the original .stl file or did you loasd and resllice a .ctb file?  If the former I would think it would work properly--if the latter (loading and re-slicing a print file) I can understand how things weent wrong.

How is you machine defined in the Chitubox [Settings] window?

I.e. this window (these are he settings for my modified MARS):

[nighteagle]

See default Setting of Mars 2 - i have the 2 Pro
Looks like your setting is incorrect?

[sardaclan]

See default Setting of Mars 2 - i have the 2 Pro
Looks like your setting is incorrect?

I know this is way old but I wanted to say that these settings worked absolutely perfect...Thanks