Injection molded cover with a grid structure for automobile loudspeakers and air vents in automobiles is molded in a PA-ABS compound

摘要

A mixture of polyamide (PA) and acrylonitrile butadiene styrene (ABS) is injection molded at not 280[deg]C into a molding tool to form at least the grid structure (2) of the cover (1). The plastic mixture is plasticized and injected by a conventional screw (9) into a tool (12,16) with cavities having flow paths of not less than180 mm. Oxygen is excluded during plasticization. Inert gas such as nitrogen or argon is fed into the machine feed hopper to purge air from between granules. Molding cavities are also supplied with inert gas and air in cavities is sucked out by vacuum. The injection tool or parts of it are made from a gas permeable material. A multi-component injection method may be used to produce the complete cover (1) in which a grid structure (2) is premolded and in a second stage another component (3) is injected to combine with the grid and form a single cover unit. Outer lying hot runner nozzles of the tool are controlled individually. Independent claims are made for: a) a cover (1) with grid-like structures for loudspeakers or vents in which at least the grid structure (2) is injection molded in a PA-ABS compound; b) use of a PA-ABS compound for injection molding of a cover (1) with grid structures (2) for covering loudspeakers and air vents; c) an injection molding tool for molding the product which has gas injectors for venting cavities in the region of the grid structure in one and/or both sides of the injection tool.