There are a few gotchas when it comes to 3D printing upgrades and/or fixes for the Monoprice Mini Delta (MPMD) 3D Printer.
- The stock dimensional accuracy is pretty terrible. Simply correcting the M92 values is not always enough.
- Not everyone's MPMD is off by the same amount, so generic advice for scaling does not always work.
- Sometimes, MPMD owners design their parts to be printed on their dimensionally inaccurate MPMD.
This part is an example of a repair part that is sized too large in the STL file in order to compensate for the designer's printer's inaccuracy. If you were to print this on a dimensionally accurate printer, such as an Ender 3 (or AM8 like I tried), then the part would be too large.
In order to solve this, you will need to scale the xy and z dimensions in your slicer to get the appropriate dimensions, as shown in the images:
Outer Diameter: 9.0 mm
Cylindrical Height: 2.0 mm
new_scale_factor = (old_scale_factor) * (desired_size / measured_size)
For example, I improved the dimensional accuracy on the MPMD by following this video, and as a result, had to scale the part as follows:
x scale = 92%
y scale = 92%
z scale = 100%
Just to be clear, the values above are what you would probably need to use on a dimensionally accurate machine (e.g. Ender 3, CR-10, Anet A8, Prusa i3, etc.). See the comments for another example.
Make sure you apply the same scale factors to both parts.
Used tree supports with touching build plate only.
Oriented the coupler so that the round part sat at the bottom and the threaded part was sticking up in the air.
I used the stock 0.4 mm nozzle and increased the line width to 0.48 to improve the part strength.
I had to re-scale the part to get the appropriate dimensions, as shown in the images.