Innovative Weld Design for a Plastic Pressure Vessel 2017-01-0468

A new weld design to form plastic hollow articles is conceived. Its design is T-shaped such that the joint loading under pressure is no longer in peel but in tension, vertically to the weld surface. This weld design can be easily achieved, overcoming the limitation of die lock in injection molding and by the hot plate weld design adopted for this welding. Test samples were built to evaluate the new weld design concept and hot plates designed to help perform this weld joint. Pull test on the conventional L-shaped and the new T- shaped welded samples show an improvement of about 50% weld strength for the new T-shaped weld design. Hence a weld joint stronger than the parent material, in forming plastic hollow articles, is possible.