Injection molding method for in-mold decoration

Abstract

The invention discloses an injection molding method for in-mold decoration, which comprises the following steps of: a. providing a film vacuum molding mould or a high pressure molding mould to make a film; b. forming a decoration pattern on the film: c. heating the film evenly which is in tension, and making the softened film into a film shell matching with a part shape through the vacuum molding mould or the high pressure molding mould; d. putting the film shell obtained from the step c in a trimming punching machine so as to die cut redundant film boundaries; and e. putting the film shell obtained in the step d in a moulding chamber of an injection mould so as to carry out clamping and injection molding. The method is characterized in that in the step e. the injection mould comprises a male mould and a female mould which form the injection mould when folded; a parting line is arranged in the folding place of the male mould and the female mould, the die cutting to the film in the step d causes the film to cover the parting line when the film is put in the injection mould. The method can improve the boundary appearance of the part greatly and product qualification rate without increasing energy consumption and processing time.

Description

technical field [0001] The invention relates to an injection molding method for in-mold decoration. Background technique [0002] IN-Moulding Decoration (IMD) is currently mostly used in mobile phones and notebook computers. Usually IMD parts are relatively flat in shape and simple in structure, and the decorative surface can only cover above the parting line. Usually this process includes the following steps: [0003] a. Provide a film vacuum forming mold or a high pressure forming mold to make a film; [0004] b, forming a decorative pattern on the film; [0005] c. The film is evenly heated under tension, and then the softened film is made into a shell that matches the shape of the part through a vacuum forming mold or a high pressure forming mold; [0006] d, place the completed film shell of c in an edge trimming punching machine to complete the punching of excess film borders. [0007] e. Provide an injection mold suitable for the IMD process, place the film shell...

AI Technical Summary

Problems solved by technology

[0008] However, the problem existing in the existing process is that the IMD coating film cannot be coated to the parting line, because there is a negative angle in the area below the parting line.

For the film coating of the parting negative angle area, there are two problems in the existing process: 1. The boundary design of the film coated to the negative angle cannot be demolded in the film vacuum forming process; 2. The film coated to the negative angle cannot It is easy to touch the film when the concave-convex mold is closed, causing damage and offset

In addition, the boundary of the IMD-coated film is often rough and has white edges, which makes the appearance quality of the parting line area of ​​the auto parts exposed to the parting line poor.

In this case, the IMD process is often limited, which affects the application of IMD parts in the automotive industry, or brings limitations to the design of automotive styling structures

For example, the die-cut film in the step d process must be smaller than or close to the parting line area, so that the film in the f process can be completely placed in the decorative surface of the injection mold, otherwise the film with unreasonable trimming will be in the injection mold. The mold clamping movement interferes, and the positioning of the film in the mold will move, resulting in appearance defects such as escape and wrinkles

In this way, there will be no decorative film surface above the parting line of the part, which will affect the appearance

The boundary of the decorative film is relatively rough, and the parting line of the part is generally the visible area, resulting in poor appearance quality of the part boundary

It brings great limitations to the shape design of parts and the structural design of parts

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