Patent ID: 6726790
Filing Date: 2004-04-27
Classification: B29C,B29K,B29L,Y10T

Abstract:
A method of frictional welding a first thermo-plastic workpiece to a second thermoplastic workpiece, comprising the steps of:a. pressing the first and second workpieces together under a compressive clamping pressure; b. moving the first workpiece relative to the second workpiece in a plane parallel to their interface sufficient to frictionally heat the interface; c. melting the interfacial surfaces of the first and second workpieces creating a melt down region; d. providing a means to restricting the lateral flow of molten material out of the gap between said interfacial surfaces; and e. retaining a molten pool of substantial depth between the workpieces from the beginning of melting to the onset of solidification, and wherein at least one of said first and second workpieces is comprised of a fiber reinforced thermoplastic;wherein said restricting means is a substantially rectangular projection along each lateral edge of said first workpiece and the thickness of each of said projections is between about 5% and about 35% of the thickness of said first workpiece, and wherein the height of each of said projections, relative to the lowest point on the initial mating surface, is at least about 25% of the dimension of the melt down region.