I just got my Original Prusa I3 mk2s and are just starting to model my own creations with Blender. My first hurdle seem to be scale when creating objects that will fit something real life.
I created a template box in blender of height 10mm, width 35mm and depth 24mm. I exported this to Slic3r, and by just eye balling the grid, the size seem to be correct after import.
After print, the result are as follows
Height 10mm in model is printed as 7,1mm in real life (70% of original size)
Width 35 mm in model is printed as 32mm in real life (91% of original size)
Depth 25 mm in model is printed as 22mm in real life (88% of original size)
Im a 3d Print beginner so I have no idea if these numbers are within the “bounds of normality” for modeling and printing. Is there anything I can do with Slic3r perhaps? Its troubeling that the Z axis is more off than X / Y. A simple quick fix, like a 10% scale increase will not work.
Super happy for help on this. Modeling things that will fit something IRL is a huge part of this for me.
I may be wrong, however that to me just sounds like the tolerances of your prints being quite large. Messing around with the temperature of both the bed and the hot end, as well as changing the extrusion speed can impact this. I would do a number of test prints (probably of a semi small cube) to refine the print setting for your machine and environment.
Also, when you export to STL, scale is not included. It is easiest to not set any scales in Blender. Blender start up defaults to “Blender Units” with no scale. Just assume that this is mm and you are good to go.
Take the starting cube and change it to be 10 x 35 x 25 and you will get an STL file with those exact dimensions in mm.
And you should calibrate your printer. My Mk2 printed perfect height, but X was off (if I asked for 12mm, I got 11) and Y was a little off (a 100mm bar printed as 98mm). These are adjustable in the firmware (look up calibration to see how to adjust it). Make sure you are using a model with exact dimensions - there are many you can download. I prefer to print square cross-section bars that are 5, 10, 20 mm long in multiple orientations to correlate any size discrepancies.
