Sometimes you come up with 3D printer models that are just too hard to print. This is where cutting 3D models digitally comes in handy.

At the top left is a custom plastic part designed for my receiving loop project. The part is a guide for winding 12 turns of small gauge wire as my loop antenna. One of these guides is meant to fit onto each of the four ends of the dowels making up the cross pieces of the loop. The wires fit into the grooves and be held in place as I wind the loop. The hole in the base is around 10 millimeters in diameter to fit onto the 3/8 inch dowel rods. Each notch in the top part is around 3 millimeters across.

The problem with this part is that it is hard to print, even with supports. There is no single side that will fit flat on the 3D printer bed. However, I noticed that if I cut the part in half along the long axis, I would have two parts that would print easily. And these could be attached back together to re-create the single model.

Cutting 3D Models Digitally

Tools like Meshmixer make cutting 3D models easy. Just import the STL file, and use the “plane cut” edit feature. If the model is not symmetrical (most are not) you need to make sure that you have mirror images so they will fit back together. You can create the two mirror image pieces by making two cuts on your model in Meshmixer. Or, you can use the mirror image feature in your 3D printer software to create it.

After printing the two component pieces (see top right picture) it is just a matter of gluing them back together. The parts are printed in PLA. Gluing PLA with Superglue (or any type of Cyanoacrylate) works well. The final product is shown in the lower picture.

Just make sure to trim off any scraps, and sand down the sides that glue together. Superglue will leave some (white) residual smudges. Use it sparingly, Compress and hold the model together for a few minutes after applying the adhesive.