Apparatus and method for the production of bimaterial hollow bodies by means of injection overmoulding

Abstract

The invention relates to an apparatus and method for the production of bimaterial hollow bodies by means of injection overmoulding. The apparatus includes: a number (n) of basic mould cavities (1) or groups of basic mould cavities (1) inserted between a number (n+1) of overmould cavities (2a, 2b) or groups of overmould cavities (2a, 2b) or vice versa; and a number (2n) of punches (3) or groups of punches (3) which are fixed to a punch holder plate (32) that is mounted such that it can move transversely (DT) on a base plate (30) that is actuated to move longitudinally (DL) in order alternately to insert each punch (3) into one of the basic mould cavities (1), so as to mould a first layer, and into one of the overmould cavities (2a, 2b), so as to overmould a second layer. The apparatus also includes release means for releasing the finished bimaterial hollow bodies (P) and valve means (21) for alternately distributing the moulding material to one or other of the outer cavities.

Description

Technical field [0001] The present invention generally relates to an equipment and method for producing bi-material hollow bodies by injection overmolding, and more specifically, for producing bi-material preforms by injection overmolding. Background technique [0002] The production of bi-material plastic parts has been a widely used technology for many years. The application field is very wide, including various technical parts, such as used in automobiles, electronic equipment, household appliances, etc., but also used in cosmetics, perfumes, and personal care products. Similarly, there are many types of raw materials, namely plastic resins, and the purpose of using this technology is for aesthetics, such as providing parts in several colors; for technology, such as providing different technical properties for different areas of the parts; or For the sake of economy, for example, the basic area of ​​the part is made of economical materials, and other areas are made of high-qua...

AI Technical Summary

Problems solved by technology

For this, the dimensions of the press must be large or the number of cavities is very limited

Furthermore, molds in dual-material injection techniques necessitate large volumes of coolant fluid that must pass through rotating joints that otherwise limit system throughput

In addition, the preform must be ejected in a displacement manner, and since the necessary force is important, the ejection system tends to cause misalignment

[0016] In the co-injection technique widely used today, the overmolded material layers are not well defined, whereby the final geometries of the base and cover layers formed of different materials cannot be precisely controlled

Even if this technology is allowed to be used to apply barrier layers, this limitation makes it neither suitable for the use of recycled materials combined with high-quality materials, nor for aesthetic bi-colors by molding and overmolding two different colored materials keynote

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