Boss Design |
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Bosses are used for the purpose of registration of mating parts or for attaching fasteners such as screws or accepting threaded inserts (molded-in, press-fitted, ultrasonically or thermally inserted).
The wall thicknesses should be less than 60 % of nominal wall to minimize sinking. However, if the boss is not in a visible area, then the wall thickness can be increased to allow for increased stresses imposed by self-tapping screws. The base radius should be a minimum of 0.25 x thickness ![]() The boss can be strengthened by gussets at the base, and by attaching it to nearby walls with connecting ribs. ![]() Hoop stresses are imposed on the boss walls by press fitting or otherwise inserting inserts. ![]() The maximum insertion (or withdrawl) force Fmaxand the maximum hoop stress, ocurring at the inner diameter of the boss, smax is given by ![]() Failures of a boss are usually attributable to:
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