Thermoplastic filament winding process

A method for continuously forming cylindrical articles, such as pipe, from one or more continuous strands of thermoplastic material which comprises the steps of guiding the strand to a rotating mandrel, heating the strand prior to the strand reaching said mandrel to a sufficient temperature to make the thermoplastic material of the strand sticky, wrapping the hot strand on the mandrel at a preselected rate using a reciprocatory motion to form a crossed helical wrap thereon, internally chilling said mandrel thereby to chill the inner surface of the formed pipe to a temperature at which the thermoplastic material adjacent to the mandrel becomes rigid, and sequentially and incrementally removing the pipe from the mandrel while the pipe is being continuously formed with a rotating gripper means turning at subtantially the same speed as the mandrel.

A method for continuously winding a substantially cylindrical article from one or more fiberglass strands saturated with hot sticky thermoplastic material, guiding with devices having means to partially cool the surface of each strand to temporarily case harden the surface of each strand sufficiently to obtain handling capabilities, reciprocating said guiding devices in close proximity to a cooling mandrel to form a cross helical wrap thereon, rotating and reciprocating the cooling mandrel, controlling the rotating and reciprocating speeds of the cooling mandrel in coordination with the reciprocatory speed of the guide devices, and sequentially and incrementally removing the pipe from the mandrel while the article is being continuously formed with a rotating gripper means turning at substantially the same speed as the mandrel.

A method for continuously forming a cylindrical article from a thermoplastic article, which comprises the steps of guiding one or more stretch oriented strands of material to a cooling rotating mandrel, reciprocating the guiding of the stretch oriented strands in close proximity to the cooling mandrel to form a cross helical wrap thereon, heating the strand in close proximity to and at its line of intersection with the cooling mandrel to at least the temperature at which the surface of the material becomes semi-molten and winding the strands to form a cylindrical article, and sequentially and incrementally removing the article from the mandrel while the article is being continuously formed with a rotating gripper means turning at substantially the same speed as the mandrel.