Living Hinges

PolyJet 3D Printing materials, including Rubber–like Digital Materials, have excellent elongation–to–break characteristics and superior tear resistance that makes them ideal for flexible hinges that can be used over and over without breaking. Create long–lasting, functional prototypes of products that include flexible hinges in a single build by using rigid materials for the body of the part, and Digital Materials with the requisite shore value for the living hinge.

PolyJet 3D Printed Living Hinges

A living hinge is a thin flexible hinge (flexure bearing) made from plastic, as opposed to cloth, leather, or some other substance, that joins two rigid plastic parts. The hinge allows the plastic parts to bend along the line of the hinge. It is typically manufactured in an injection molding process that creates all three parts at one time as a single entity. A thinned section of the plastic part bends to allow movement.

The hinge’s minimal friction and little wear make it useful in the design of micro electromechanical systems. If correctly designed and constructed, living hinges remain functional throughout a product’s lifetime as these hinges can flex more than a million cycles without failure.

Polyethylene and polypropylene are considered to be the best resins for living hinges due to their excellent fatigue resistance. The low cost and ease of manufacturing makes them quite common in disposable packaging.

Why Connex 3D printing?

Connex printing systems can print parts with living hinges easily and quickly. This is possible thanks to the excellent elongation–to–break properties and very good tear resistance of Digital Materials. These two traits allow for the generation of living hinges that withstand repeated bending and flexing. Living hinges with Connex–driven parts can be used for:

  • Caps and packaging
  • Clips
  • Left and right clamp shells

Tips for Great 3D Printed Living Hinge Prototypes

When working on you CAD design, assign a specified shell to each element in your design. When converting that file to an STL, convert the file while defining each STL as a part of your assembly. This will allow you to then clearly define the area related to the living hinges.