Abstract: As having characteristics of high strength, low weight and vibration reducing, metal-polymer composite parts have been widely used in the aerospace, automotive manufacturing, energy etc. Exploring convenient technology to produce composite parts with high efficiency, good interface bonding strength, and easily complex features forming is pursued by the industrial field. A method producing steel-thermoplastic polyurethane (TPU) composite parts by using injection molding process was proposed. Firstly, the steel surface was sandblasted, oxidized and silanized to change its microstructure and composition. Then, the surface-modified sample was placed in the mold cavity, and TPU melt was directly injecting onto the metal surface to form the steel-TPU composite parts. Annealing treatment was also used to eliminate the residual stress and promote the interaction between amino functional groups and TPU functional groups, which further improving the interface bonding strength of the composite parts. The results show that when the interfacial bonding strength of the composite components reaches 17.8 MPa, the TPU material was damaged, while the bonding interface did not fail. Lastly, a kind of steel-TPU flexible composite fixture was successfully fabricated by using the presenting method. The working pieces with different diameters can be clamped by applying radial force, thus the versatility of the fixture can be expanded.

Key words: integrated molding technology, bonding strength, injection molding process, composite components