In a fastening method and fastening apparatus, workpieces are fastened using a fastener made of a thermoplastic polymer comprising carbon fibers. The method and apparatus involve induction heating of the carbon fibers to soften the thermoplastic polymer and then plastically deforming axial ends of the fastener using a die or dies to form first and second heads while a shaft body or a shaft part of the thermoplastic polymer comprising the carbon fibers is inserted through respective through holes formed in the workpieces.

A fastening apparatus includes a fastening device (1, 3) that heats in a non-contacting state, and then applies pressure to, a shaft part (11b) or shaft body (111) while it is inserted through the through holes (W10, W20) of workpieces (W1, W2), thereby forming at least a second head part (11c) of a fastener (11). The fastening device (1, 3) includes: a fastening die (15) that forms the second head part (11c); and a shaft-part pressure-applying device (9) that applies the pressure to the fastening die (15). A determining device (5) determines whether the fastener (11) is defective or not by calculating a load curve defined by the time and the load during which the pressure was applied and then determining whether an amount of change per unit of time in the load curve after a reference load has been exceeded is within a range of a predetermined reference value.

A heat sink for use in induction welding includes a number of tiles, wherein the tiles are electrically non-conductive and have a thermal diffusivity of greater than about 25 mm2/sec. A joint flexibly joins the tiles together.

A method to prepare a composite laminate object containing an extrusion grade 7xxx Al substrate and a fiber-reinforced polypropylene layer adhesively laminated to the substrate; is provided. The process includes shaping and cutting an extruded 7xxx aluminum to a profile, assembling a layered arrangement of the 7xxx Al profile as substrate, an adhesive film and a fiber reinforced polypropylene preform, heating the layered arrangement to a temperature of 160-175 C. to melt the polypropylene and activate the adhesive film, applying pressure to at least a surface of the fiber reinforced polypropylene preform to mold the preform to the shape of the extruded 7xxxAl substrate and obtain a semi-finished laminate object, cooling the semi-finished laminate object to 90 C., optionally, cooling the semi-finished laminate object to room temperature for inventory storage; heat treating the semi-finished laminate object at 90 C. for 2 to 8 hours; and then heat treating the semi-finished laminate object at 130 C. to 150 C. for 8 to 16 hours; and cooling the heat treated object to obtain the composite laminate object.

A method of induction welding a first thermoplastic composite (TPC) to a second thermoplastic composite (TPC) using an induction coil includes forming a weld interface area between the first TPC and the second TPC, cooling the first TPC with a cooling apparatus before heating by the induction coil, and inductively heating the weld interface area with the induction coil after cooling the first TPC.

A method of joining workpieces includes the steps of bringing a first workpiece and a second workpiece together, induction heating a susceptor material, and pressing the workpieces together. Each workpiece may include a thermoplastic material, and the workpieces are brought together at a joint interface so that a protrusion of the first workpiece is aligned with a receptacle of the second workpiece. The susceptor material is in contact with the thermoplastic material of the first workpiece during heating such that the thermoplastic material of the first workpiece softens. The step of pressing is performed while the thermoplastic material of the first workpiece is softened, thereby reshaping the first workpiece where the susceptor material is in contact with the thermoplastic material of the first workpiece. The protrusion is deformed to form an interlock with the receptacle at the joint interface.

A heat sink for use in induction welding includes a flexible backing and a number of tiles disposed on the flexible backing in a single layer, wherein the tiles are electrically non-conductive and thermally conductive.

A heat sink for use in induction welding includes a number of tiles, where the tiles are electrically non-conductive and thermally conductive, a joint flexibly joining the tiles together, and a fluid path formed through the heat sink for communicating a coolant therethrough.

A method of dissipating heat from a surface of a first thermoplastic composite (TPC) being inductively welded with a second thermoplastic composite (TPC) includes flexing a heat sink during placement to conform to the surface of the first TPC, cooling the heat sink, applying inductive heat to a weld interface area between the first TPC and the second TPC, and drawing off heat via the heat sink from the surface of the first TPC.

A method of induction welding a first carbon fiber thermoplastic composite (TPC) to a second carbon fiber thermoplastic composite (TPC) using an induction coil includes aligning the first TPC with the second TPC to form a weld interface area, flexing a heat sink onto a surface of the first TPC between the weld interface area and the induction coil, and inductively heating the weld interface area with the induction coil.