A living hinge or integral hinge is a thin flexible
hinge (
flexure bearing) made from the same material as the two rigid pieces it connects.
Description
A living hinge or integral hinge is a thin flexible
hinge (
flexure bearing). It is made from the same material as the two rigid pieces it connects. It is typically thinned or cut to allow the rigid pieces to bend along the line of the hinge. The minimal
friction and very little
wear in such a hinge makes it useful in the design of
microelectromechanical systems, and the low cost and ease of manufacturing makes them quite common in
clamshell containers and other
disposable,
recyclablepackaging.[1]
Plastic
Plastic living hinges are typically manufactured in an
injection molding operation[2][3] that creates all three parts at one time as a single piece, and if correctly designed and constructed, it can remain functional over the life of the part.
Thermoforming can also produce hinged products.
Polyethylene and
polypropylene are considered to be the best
resins for living hinges, due to their excellent
fatigue resistance.[4][5]Acrylonitrile butadiene styrene (ABS) is also common.
[6]
Wood
A variant on the
kerf bend can be used to create living hinges in laser cut wood. The technique is popular for making light-duty hinges with large radii.[7] It is also possible to create a living wood joint by hand, but the result is less accurate.[8]