Soft fabric inlaying mold-closing normal-pressure injection molding method

Abstract

The invention discloses a soft fabric inlaying mold closing normal-pressure injection molding method, belongs to the technical field of normal-pressure injection molding, and breaks through a traditional coating technology, a low-pressure injection molding technology, a PC3S technology and other interior soft product forming technologies. A pre-cut soft fabric is adopted and matched with special injection mold design and process design, the pre-cut fabric is placed in an injection mold, a normal-pressure injection molding method is adopted, and a coating type interior product which is low in odor, environmentally friendly, few in manufacturing procedure, low in cost and soft in product surface quality is obtained through one-step injection molding. Compared with the traditional PC3S technology which can only realize the assembly of the B surface of the product, the invention can realize the arrangement of the edge position of the product on the visual surface, greatly increases the degree of freedom of product design, and can replace the traditional automobile soft interior manufacturing technology.

Description

Technical Field

[0001] The invention belongs to the technical field of normal pressure injection molding, in particular to a normal pressure injection molding method for soft fabric inlaying and mold closing. Background Art

[0002] Currently, the soft interior technology used for automotive interior products at home and abroad includes the following three aspects.

[0003] Coating technology: The coating process must be glued, usually with low-cost solvent glue, which has a strong odor. The glue spraying process has high requirements for the ambient temperature and pollutes the environment, and the volatile substances in the glue continue to emit during use; the product is prone to debonding after long-term use; the process is complicated, requiring multiple steps from injection molding skeleton production, fabric cutting, glue spraying, activation to pressing, punching, trimming, etc., with many steps, long process time, and large area occupied.

[0004] Low-pressure injection molding technology: Large fabrics that exceed the product size are placed in the injection mold in advance, the fabric utilization rate is low, and this process requires the equipment to have low-pressure function. The process adjustment process is complicated and the scrap rate is high. After injection molding, trimming, punching and flanging processes are also required, and the soft effect cannot reach the coating level.

[0005] PC3S technology: While the product has the advantages of no need for glue, one-step molding, no need for post-processing and high production efficiency, it is impossible to place the edge of the product on the visible surface, and the feasibility of application needs to be based on product design.

[0006] Application number 2011101979951, the patent name discloses a method for combined mold injection molding of pre-cut soft small fabrics. This method has very high requirements for product design. Due to the mold parting and sealing glue indentation on the edge of the fabric, the product must be assembled on the B side, which cannot meet the current customer's product design trend of mostly A-side assembly. Summary of the invention

[0007] In view of the above problems, the present invention provides a soft fabric inlay mold closing normal pressure injection molding method.

[0008] The technical solution of the present invention is as follows: a method for soft fabric inlay mold closing normal pressure injection molding, comprising the following steps:

[0009] S1 Product Design: When designing a product, a process supplement area is reserved on the edges around the product to design hanging holes for the fabric. The diameter of the hanging holes is 6mm. The distribution of the hanging holes requires that one is arranged near each corner area of ​​the product. The product is designed for A-side assembly or B-side assembly.

[0010] S2 mold design: The thickness of the mold cavity is processed according to the thickness of the plastic skeleton plus the thickness after the skin is compressed. The gate of the mold is designed on the rib position on the back of the product. The mold is inverted and the fixed mold is designed with two sets of hanging pins for subsequent hanging of fabrics. The mold design needs to separate the injection molding sealing surface from the mold parting surface, and move the mold closing mark to the edge of the fabric.

[0011] S3 fabric selection: The outer surface of the fabric is made of PVC and fabric, the inner surface uses non-woven fabric as the heat-resistant layer, the material is polyethylene terephthalate, the thickness is 1.2mm, and the thickness of the middle foam layer is 3.5mm;

[0012] S4 Fabric cutting: Fabric cutting should be carried out according to the visible surface contour of the product, and the edge of the fabric should be 5mm-8mm longer than the corresponding visible surface edge;

[0013] S5 skeleton material selection: The skeleton material is polypropylene, and the melt index requirement of the material is 25g / 10min;

[0014] S6 injection molding production: hang the fabric on the mold hanging needle, close the mold and inject it at normal pressure;

[0015] S7 Pressing and flanging: Pressing and flanging the edge of the product to achieve A-side or B-side assembly of the product.

[0016] Further, step S6 is specifically as follows: the injection speed is set in the range of 55mm / s-60mm / s, the injection pressure is 70bar-80bar, the holding time is set to 4-6 seconds, the injection molding machine barrel temperature is between 180℃-200℃, and the mold hot runner temperature is set to 210℃.

[0017] The beneficial effects of the present invention are:

[0018] The present invention breaks through the limitation that automobile covering products must be made by gluing and trimming, or low-pressure injection molding, and realizes independent innovation of key manufacturing technologies for automobile interior covering products. It is a technology with excellent appearance quality, high production efficiency, cost advantages, low scrap rate, and can be used for mass production of products. This technology covers technical innovations in raw material solutions, injection mold solutions, process solutions, etc. This project complies with the national automobile industry policy and is of great significance for promoting enterprise technological progress and meeting the strategic needs of national technological innovation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The process flow chart of the present invention is DETAILED DESCRIPTION

[0020] It should be noted that in the description of the present invention, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect" and the like should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral connection; the connection can be a mechanical connection or an electrical connection; the connection can be a direct connection or an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Automotive interior door covering products are key automotive interior parts, and are also the mainstream manufacturing process for current automotive interiors, and are also key components for realizing the concept of automotive comfort and environmental protection. This project breaks through the limitation that automotive covering products must be made using multiple processes such as gluing and trimming, or low-pressure injection molding, and realizes independent innovation of key manufacturing technologies for automotive interior covering products. It is a technology with excellent appearance quality, high production efficiency, cost advantages, low scrap rate, and can be used for mass production of products. This technology covers technical innovations in raw material solutions, injection mold solutions, process solutions, and other aspects. This project is in line with the national automotive industry policy and is of great significance for promoting corporate technological progress and meeting the strategic needs of national technological innovation.

[0023] The method and process of the present invention breaks through the traditional coating technology, low-pressure injection molding technology, PC3S technology and other soft interior product molding processes. The pre-cut soft fabric is matched with the special injection mold design and process design, and the pre-cut fabric is placed in the injection mold. The normal pressure injection molding method is used to inject a low-odor, environmentally friendly, less manufacturing process, low cost and soft surface quality coated interior product in one step. Compared with the disadvantage that the traditional PC3S technology can only realize the B-side assembly of the product, this invention can realize the edge position of the product on the visible surface, greatly increasing the freedom of product design, and can replace the traditional automobile soft interior manufacturing technology.

[0024] A soft fabric inlay mold-jointing normal pressure injection molding method comprises the following steps:

[0025] (1) Product design: When designing a product, a process supplement area is reserved on the edges around the product to design hanging holes for the fabric. The diameter of the hanging holes is 6 mm. The distribution requirement for the hanging holes is to arrange one near each corner area of ​​the product. The product design can be designed for A-side assembly or B-side assembly;

[0026] (2) Mold design: The thickness of the mold cavity is processed according to the thickness of the plastic skeleton plus the thickness after the skin is compressed. The gate of the mold is designed on the rib position on the back of the product. This structure can effectively prevent the melt from directly burning the visible surface of the product. Compared with conventional injection molds, the mold needs to be inverted, and the fixed mold is designed with two sets of hanging pins for subsequent hanging of fabrics. The mold design needs to separate the injection molding sealing surface from the mold parting surface to ensure the edge sealing of the injection molding. At the same time, the mold closing mark is moved to the edge of the fabric to prevent the A-side assembly from leaking out after coating.

[0027] (3) Fabric selection: The outer surface material of the fabric is suitable for PVC and fabric. The inner surface requires non-woven fabric as the heat-resistant layer. The material is polyethylene terephthalate (PET), with a thickness of 1.2mm, and the thickness of the middle foam layer is 3.5mm;

[0028] (4) Fabric cutting: Fabric cutting should be carried out according to the visible surface contour of the product, and the edge of the fabric should be 5mm-8mm longer than the corresponding visible surface edge;

[0029] (5) Skeleton material selection: The skeleton material is polypropylene, and the melt index requirement of the material is 25g / 10min;

[0030] (6) Injection molding: hang the fabric on the mold hanging needle, close the mold and perform normal pressure injection molding;

[0031] (7) The injection process parameters follow the following control method: the injection speed setting range is 55 mm / s-60 mm / s, the injection pressure is 70 bar-80 bar, the holding time is set to 4-6 seconds, the injection molding machine barrel temperature is between 180 °C and 200 °C, and the mold hot runner temperature is set to 210 °C.

[0032] (8) Pressing and flanging: Pressing and flanging the edge of the product can realize the assembly of the A side of the product.

[0033] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. A soft fabric inlay mold closing normal pressure injection molding method, characterized in that: include: S1 Product Design: When designing a product, a process supplement area is reserved on the edges around the product to design hanging holes for the fabric. The diameter of the hanging holes is 6mm. The distribution of the hanging holes requires that one is arranged near each corner area of ​​the product. The product is designed for A-side assembly or B-side assembly. S2 mold design: The thickness of the mold cavity is processed according to the thickness of the plastic skeleton plus the thickness after the skin is compressed. The gate of the mold is designed on the rib position on the back of the product. The fixed mold is designed with two sets of hanging pins for subsequent hanging of fabrics. The mold design needs to separate the injection molding sealing surface from the mold parting surface, and move the mold closing mark to the edge of the fabric; S3 fabric selection: The outer surface of the fabric is made of PVC and fabric, the inner surface uses non-woven fabric as the heat-resistant layer, the material is polyethylene terephthalate, the thickness is 1.2mm, and the thickness of the middle foam layer is 3.5mm; S4 Fabric cutting: Fabric cutting should be carried out according to the visible surface contour of the product, and the edge of the fabric should be 5mm-8mm longer than the corresponding visible surface edge; S5 skeleton material selection: the skeleton material is polypropylene, and the melt index requirement of the material is 25g / 10min; S6 injection molding production: hang the fabric on the mold hanging needle, close the mold and inject it at normal pressure; S7 Pressing and flanging: Pressing and flanging the edge of the product to achieve A or B side assembly of the product.

2. A soft fabric inlay mold closing normal pressure injection molding method according to claim 1, characterized in that: Step S6 is specifically as follows: the injection speed is set in the range of 55mm / s-60mm / s, the injection pressure is 70bar-80bar, the holding time is set to 4-6 seconds, the injection molding machine barrel temperature is between 180℃-200℃, and the mold hot runner temperature is set to 210℃.

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