An injection molding process method of a plastic part on a metal shell to form a high-strength combination comprises: forming a molding cavity which is inwardly concave from the outer surface and extending through flanges at periphery of the metal shell to area beneath bridges protruding from flanges, the bridges being removed after the injection molding. A plastic part with slight deformation is in the molding cavity and is tightly combined with the metal shell due to the bridges. The protruding bridges can be removed from the flanges by milling or cutting without damaging the plastic part, thus the plastic part does not require to be remachined, and the appearance of the metal shell is not affected.

An ultra-high molecular weight, ultra-fine particle size polyethylene has a viscosity average molecular weight (Mv) greater than 1×10.sup.6. The polyethylene is spherical or are sphere-like particles having a mean particle size of 10-100 μm, having a standard deviation of 2-15 μm and a bulk density of 0.1-0.3 g/mL. Using the polyethylene as a basic polyethylene, a grafted polyethylene can be obtained by means of a solid-phase grafting method; and a glass fiber-reinforced polyethylene composition comprising the polyethylene and glass fibers, and a sheet or pipe prepared therefrom; a solubilized ultra-high molecular weight, ultra-fine particle size polyethylene; and a fiber and a film prepared from the solubilized ultra-high molecular weight, ultra-fine particle size polyethylene may also be obtained. The method has simple steps, is easy to control, has a relatively low cost and a high repeatability, and can realize industrialisation.

A method of bonding a first object to a second object includes the steps of: providing the first object including thermoplastic material in a solid state, providing the second object including a proximal surface, applying a mechanical pressing force and a mechanical excitation capable to liquefy the thermoplastic material until a flow portion of the thermoplastic material is flowable and penetrates into structures of the second object, and stopping the mechanical excitation and letting the thermoplastic material resolidify to yield a positive-fit connection between the first and the second object. The second object has a region of low density, wherein the protrusion penetrates the region of low density at least partly before the thermoplastic material is made flowable, and wherein the first object includes a protruding portion after the step of letting the thermoplastic material resolidify, the protruding portion at least partly penetrates the region of low density.

A method of bonding a first object to a second object includes the steps of: providing the first object including thermoplastic material in a solid state, providing the second object including a proximal surface, applying a mechanical pressing force and a mechanical excitation capable to liquefy the thermoplastic material until a flow portion of the thermoplastic material is flowable and penetrates into structures of the second object, and stopping the mechanical excitation and letting the thermoplastic material resolidify to yield a positive-fit connection between the first and the second object. The second object has a region of low density, wherein the protrusion penetrates the region of low density at least partly before the thermoplastic material is made flowable, and wherein the first object includes a protruding portion after the step of letting the thermoplastic material resolidify, the protruding portion at least partly penetrates the region of low density.

The present specification relates to a joint body of different materials, and a method of manufacturing the same. The joint body includes a metal layer; and a resin layer provided on and in contact with one surface of the metal layer. The metal layer comprises two or more etching grooves and two or more burrs provided on a surface of the metal layer adjacent to the etching grooves.

The present specification relates to a joint body of different materials, and a method of manufacturing the same. The joint body includes a metal layer; and a resin layer provided on and in contact with one surface of the metal layer. The metal layer comprises two or more etching grooves and two or more burrs provided on a surface of the metal layer adjacent to the etching grooves.

A composite assembly with a laminate of fibre plies impregnated with a laminate matrix material is disclosed having pad of fibre plies impregnated with a pad matrix material, and a part with a body with protrusions which extend from the body and penetrate at least some of the fibre plies of the pad. The pad is bonded to the laminate by a stepped lap joint or a scarf joint. The assembly is manufactured by pressing the protrusions into the pad, and after the protrusions have been pressed into the pad, curing a pad matrix material impregnating the pad, and bonding the pad to the laminate.

A composite assembly with a laminate of fibre plies impregnated with a laminate matrix material is disclosed having pad of fibre plies impregnated with a pad matrix material, and a part with a body with protrusions which extend from the body and penetrate at least some of the fibre plies of the pad. The pad is bonded to the laminate by a stepped lap joint or a scarf joint. The assembly is manufactured by pressing the protrusions into the pad, and after the protrusions have been pressed into the pad, curing a pad matrix material impregnating the pad, and bonding the pad to the laminate.

A portable welding device comprising: a base facing a work surface, designed to receive tapes in electrically conductive composite materials to be joined or defined by at least one already positioned tape; an operating head receiving one tape at a time and movable with respect to the base along at least a first movement line parallel to the work surface; a motorized arm connecting the operating head to the base and selectively activatable to impart movements to the operating head; and feeding means selectively activatable to feed one tape at a time to the operating head and connected to the operating head; the operating head comprises a positioning roller receiving a tape at a time; a pressure roller spaced from and aligned with the positioning roller along the first movement line; and an inductor interposed between the positioning roller and the pressure roller with reference to the first movement line.

A portable welding device comprising: a base facing a work surface, designed to receive tapes in electrically conductive composite materials to be joined or defined by at least one already positioned tape; an operating head receiving one tape at a time and movable with respect to the base along at least a first movement line parallel to the work surface; a motorized arm connecting the operating head to the base and selectively activatable to impart movements to the operating head; and feeding means selectively activatable to feed one tape at a time to the operating head and connected to the operating head; the operating head comprises a positioning roller receiving a tape at a time; a pressure roller spaced from and aligned with the positioning roller along the first movement line; and an inductor interposed between the positioning roller and the pressure roller with reference to the first movement line.