Molded-in hinge

Fig. 3-38 A molded living hinge in the as-molded position (a) and a flexed position (b).

The rigid urethane foam concept with integral skins has also found considerable interest in the automotive industry for exterior body parts, such as engine or trunk compartment lids, fenders and even full roofs. These parts can be reinforced with metal inserts where necessary or hinges and fasteners can be molded in for ready mounting. 

Polyallomer lightweight cases can be molded entirely in one piece. Back, front, hinges, handles, and snap clasps can be molded in at the same time in a wide range of colors. Polyallomer is thus used in such injection molded items as fishing tackle boxes, typewriter cases, gas-mask cases, and bowling-ball bags. 

There are three techniques used to fabricate integral hinges molded-in (by injection or blow molding), cold worked, extruded, and coining. 

HoUow mol ding as the name implies is a molded product with a hoUow center such as Easter eggs, bunny rabbits, and Santa Claus. The molds used in hoUow mol ding are divided in two halves and connected by a hinge. Chocolate is deposited into one half of the mold. The mold is then closed and rotated so that the Uquid chocolate completely coats the inside surface of the mold. After cooling the molds are opened and the piece removed. 

Consolidation Even though blow molding provides the capability of providing multiple products combined into one, by including hinges the designer has an added feature. The ability to produce many articulated products in one shot has always opened new design... 

Composition 57% copper, 40% zinc, and 3% lead. It is used in decorative molding, hinges, locks, and industrial forgings. 

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