Method for overmolding an insert made of prepreg and its use

Abstract

The invention relates to a method of overmolding an insert made of prepreg for the manufacture of automotive parts, comprising the steps of: heating the insert; placing the heated insert in an injection mold comprising a first part and a second part at a temperature; closing the mold by compacting the insert; cooling only the first part of the mold until the first part reaches a second temperature, while maintaining the second part of the mold at the first temperature, said first part The second temperature is lower relative to said first temperature; the insert is separated from the first part of the mold by means of at least one jet of air, whereupon the insert is attached to the second part of the mold; the insert is overmolded with sprayed thermoplastic material . Due to the relatively high temperature of the insert during overmolding, a good bond with the overmolding thermoplastic is ensured. At the same time, because the temperature of one part of the mold is appropriately lowered, the effect of the compaction process of the insert can be largely preserved.

Description

technical field [0001] The present invention relates to the field of manufacture of motor vehicle components, and more particularly to a method of overmoulding an insert made of prepreg and its use. Background technique [0002] In the field of automotive parts manufacturing, inserts made of composite materials are widely used in various automotive parts due to their complex and varied shapes and excellent mechanical properties, such as bumper beams and tailgate boxes. , Side door reinforcements, roof arches, front pillars / center pillars / rear pillars, etc. The insert is usually molded from a composite material overmolded ("Overmolding" in English) thermoplastic made of prepreg. [0003] The term "prepreg" ("PREPREG" in English)" is a commonly used intermediate material for the manufacture of composite materials, usually consisting of a plastic matrix and reinforcements (such as fibers or fabrics) impregnated in the matrix. Due to the inclusion of reinforcements, prepregs h...

AI Technical Summary

Problems solved by technology

In the prior art, the compacted prepreg insert needs to be cooled and removed from the mold before overmolding. However, the temperature of the prepreg insert is relatively low at this time, which cannot ensure the thermoplasticity between the injected thermoplastic and the prepreg matrix. The plastic is well bonded, which can lead to defective inserts and reduced mechanical properties

Moreover, if the plug-in after cooling and demoulding is reheated, it is easy to regenerate air holes in the compacted prepreg plug-in, or damage the bond formed between the prepreg matrix and the fiber reinforcement, thus detracting from the compaction process. effect, resulting in possible defective inserts, or reduced mechanical properties

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