Perfect Gridfinity Holes

TL;DR

This STL is meant to be used as a Negative Volume modifier to fix Zack's messy, sloppy holes found in the bottom of (nearly) all Gridfinity parts.

1. In your slicer, add this STL to your Gridfinity part(s) as a negative volume. 
   1. UPDATE: Or use the Fusion360 file to generate your own, see Customization below.
2. Place the negative volume on the bed and align it in the X/Y with the holes in the bottom of your part(s). 
3. Repeat for each set of holes, offset by multiples of 42mm in the X and/or Y. 
4. Hit slice and marvel at the properly bridged holes in the bottom of your Gridfinity parts.
   • NOTE: Some Gridfinity parts have magnet holes that are set slightly deeper than the standard model. Raise the negative volume one layer height and try again, repeating until it works.

About

The magnet holes in the bottom of Gridfinity accessories are printed into thin air. While this may not be an issue inside of Voidstar Labs, those of us without access to prototype E3D high-flow/low-gravity hotends are stuck doing lots of post-print cleanup, or adding supports to every single print and then doing lots of post-print cleanup. If only there were a better way…

Turns out, there is! But who has the time and editable document quota to remix every single Gridfinity part to add bridged holes? Instead, just add this model as a Negative Volume in your slicer and it'll cut the bridging fix for you.

Customization

Use the attached parametric Fusion 360 file to generate your own negative volume models for whatever bin dimension and layer heights you want. You can also use it to generate bins with the bridgeable holes already in them.

The relevant parameters are layerHeight, slotsDeep, and slotsWide. 

Note that due to a bug in Zack's original F360 file, you may have to edit the storage bin extrude feature named storage-bin- EDIT AND ”OK" THIS TO FIX PATTERN and then click OK. You don't need to change anything about the extrude, just opening the feature settings and clicking OK is enough. This forces Fusion to recalculate some things that it needs to make the repeating pattern work.

The Fusion 360 project file has added cutouts for proper hole bridging on Gridfinity bins, and that is used to generate the parametric negative volume models parametrically. ixing Zack's messy, sloppy holes.