Drywall Anchor

There are many types of commercially available drywall anchor. However, most of those designs don't perform well when 3d printed. So rather than recreating a design optimized for injection molding and adapting it to 3d printing I decided to design a drywall anchor that utilizes the advantages of 3d printing by incorporating design elements unavailable to traditional manufacturing. This design uses crossing compliant hinges that translate linear pressure from the bolt end to rotate the braces against the back of the drywall. 

Printing:

PETG or another material with similar strength and flexibility should be used to print this model. PLA is too brittle and will break during installation. Print the model on it's side as it is oriented with no supports or brims. Layers should be 0.2mm as the dimensions of the model were carefully chosen for this layer height. At least 3, but preferably 4 perimeters are recommended. Infill percentage doesn't matter much because almost all of the stresses are on the perimeters. 

Installation:

This model is designed for ½" (12.7mm) gypsum drywall. It may work on 5/8" or 3/8" drywall but this has not been tested. There are two models, one threaded for 8-32 machine screw and the other threaded for M4 bolts. The bolt must be inserted ¾" (19mm) into the anchor to fully extend the braces. Make sure your bolts are long enough to pass through whatever object you are securing to the wall plus ¾". 

To install, first drill a ½" (13mm) hole in the location where you need an anchor. Then gently tap the anchor through the hole with a hammer. The square corners of the anchor will cut into the drywall and prevent the anchor from spinning. Be careful that the anchor is centered in the hole and perpendicular to the wall so that the anchor goes in straight and doesn't tear out the paper on the back of the drywall. Then put the bolt though the object to be mounted to the wall and screw the bolt into the anchor until it is tight or it has reached 19mm past the front of the anchor. 

I tested an anchor printed with Polymaker PolyMax PETG and installed into ½" drywall mounted vertically (like a wall) and it held over 75 pounds (34 kg). I would not recommend putting anywhere near that amount of weight on a single drywall anchor. Installed in a ceiling where the force is directed straight away from the drywall the anchor will support even less weight. Use your best judgement about where and when is appropriate to use drywall anchors. 

Please let me know if you found this model useful or if you have any suggested improvements. Remixes are welcome.