How much do you know about the manufacturing process of car interiors?

Slush molding

1, what is slush molding?

Slush molding, also known as rotary molding, is mainly used to make the skin of soft instrument panels and door guards. This technology originated in Japan and was not introduced to China until the early 21st century. At first, it was only used in a few joint ventures, and in recent years it has been gradually applied to domestic independent brands.

2. Advantages and disadvantages

Advantages: a wide range of raw materials, low prices, design and production experience. The leather pattern is not only clear and beautiful, but also consistent. The product has good elasticity and low shrinkage, and can be designed with complex modeling features.

Disadvantages: high mold investment cost and short service life (general mold quality assurance is only 20000~30000); high equipment investment cost; molds need to be cleaned continuously, resulting in long auxiliary working hours.

PU spraying (polyurethane)

PU spraying technology is a new type of skin forming technology that has developed rapidly in recent years, which is mainly used for the skin of the instrument panel and the skin of the guard plate.

1. Molding process

PU spraying refers to spraying mold release agent on the surface of the skin forming mold, then spraying mold paint (different colors of mold paint can be sprayed according to product needs), then spraying liquid PU raw materials (skin thickness can be controlled by spraying manipulator), and finally cooling the mold.

2, relative to the advantages of slush molding process.

The first part of slush molding process and PU spraying process is the main manufacturing process of soft instrument panel skin, but compared with slush molding process, PU spraying has many advantages, such as can realize double color instrument panel surface and make modeling design more flexible; The equipment is also relatively simple, which can greatly reduce energy consumption, especially the price reduction of PU powder raw materials in recent years, which makes the price of PU skin conducive to recycling may compete with traditional PVC skin.

In-mold transfer (IMD)

1. The concept and application of in-mold transfer

In-mold transfer is a process that is synchronized with the decoration during the molding process. By decorating plastic parts during the molding process, traditional molding decoration, online production inventory and additional operation steps can be reduced, and production costs can be greatly reduced. Mainly used for: instrument panel, air conditioning panel, interior parts, headlight shell, logo, etc.

The film thickness is generally 0.5mm, and its composition structure is shown in the figure below. The patterns on the film can be made into different effects, such as wood grain, metal wire drawing, aluminum, carbon fiber, brightness and matte. Due to the protection of the PET layer, the film has good scratch resistance and corrosion resistance, and the pattern will not be damaged after long-term use.

2. Molding process

Before the mold is closed, the film of different patterns is adsorbed to the cavity surface of the injection mold, and then the molten plastic (usually PC). ABS) is injected into the mold to integrate the diaphragm with the plastic.

3. Advantages and disadvantages

Advantages:

1. Integrate molding, simplify the process, reduce production/inventory costs and working time, shorten the product production cycle, and improve production efficiency;

2. All kinds of reliability tests are the highest level in the industry to ensure the stability and durability of the product;

3. High automation production, to ensure high yield and stable production;

4. The use of automatic printing and environmental protection ink, in line with environmental requirements;

5. Multi-color printing, such as wood grain, carbon fiber, metallic color, etc. The surface texture and pits of the product can be colored at the same time. For transparent parts, a translucent effect can be produced. With stereo texture.

6. Surface hardening (HardCoat) treatment (pencil hardness up to 3H) has abrasion resistance and aesthetics.

Disadvantages:

On the surface of the product, the thickness of the printed pattern layer is only a few microns. After the product is used for a period of time, the printed pattern layer is easy to wear and fade, resulting in an unsightly surface. In addition, the weakness that IMR technology cannot overcome is that the new product development cycle is long, the development cost is high, and the pattern color cannot be flexibly changed in small batches.

In-mold embedded film (INS)

1, mold embedded film forming process principle

The film is adsorbed in the molding mold by high pressure in advance to form the shape of the outer surface of the product, then the edge is cut, placed in the injection mold of the product, and then injected with molten plastic.

2. Advantages relative to in-mold transfer

Compared with IMD technology, the biggest advantage of INS technology is that it can generate larger surface stretch decoration. Although vacuum adsorption and cutting tools are added, the process is complicated and the single-piece production cost is higher, but INS technology can be directly used in ordinary injection molding machines to save film transfer positioning devices. The following figure shows two processes that can compare different surface effects.

The emergence of in-mold transfer printing and in-mold film embedding technology is a leap in the design of color texture for automotive interiors and exteriors. They completely break through the traditional water transfer technology on the product color texture restrictions. The combination of different colors and textures on the surface of the product can meet the individual needs of different customer groups, just switch different films. Compared with the traditional process, the production efficiency is greatly improved, the process is more environmentally friendly, and the product has higher corrosion resistance.

Water assisted injection molding

Auxiliary injection molding (WIT or) WAIM) originated in Germany at the beginning of the 21st century and has been gradually applied all over the world. It is a kind of gas-assisted injection molding (GIT). With the continuous maturity of technology, the application of new injection molding technology will be more and more extensive. Now, there are many successful application cases in automobile door handle.

1. The basic principle of water-assisted injection molding process

The basic principle is to inject the polymer melt into the mold cavity; introduce water into the melt, and the water flows to the low-pressure area of the part in the direction of least resistance; when the running water flows in the part, it empties the thick-walled section by replacing the material to form a hollow Part, and the replaced material is used to fill the rest of the part; after the filling process is completed, the water continues to provide holding pressure to solve the problem of the volume shrinkage of the part during the cooling; after the mold is cooled, the water is drained and the part is removed.

2. Compared with gas-assisted injection molding,

Compared with gas-assisted injection molding, WAIM technology can not only reduce or eliminate warpage, but also can be used to produce products with thinner wall thickness, more uniform, and smoother inner surface to avoid shrinking marks, save materials and reduce product internal stress. In addition, since the thermal conductivity of water is 40 times that of N2, in addition to ordinary cooling molds, water injection will also cause internal cooling of plastic products. Therefore, compared with gas, the cooling time can be shortened by 70% after using water, and the time for the product to reach the demolding temperature is much shorter. At the same time, water is much cheaper than N2.

Disadvantages: Need for precise control. If too little melt is initially injected, water may penetrate the melt into the mold cavity. The pressure of the water injection must be higher than the pressure of the melt to push the melt to the end of the cavity. Injection molding is not feasible and requires high surface quality.

low pressure injection molding

1. What is low pressure injection molding?

Low pressure injection molding technology is a packaging technology that uses very low injection molding pressure to inject hot melt materials into the mold and quickly solidify. It has the functions of insulation, temperature resistance, impact resistance, vibration reduction, moisture-proof, waterproof, dust-proof, and chemical corrosion resistance., It has excellent sealing performance and excellent physical and chemical properties of hot melt materials, and has a good protective effect on electronic components.

2. Molding process and application

The skin is put into the mold in advance, and then the molten plastic is injected into the closed mold cavity by the thrust of the screw, and then cured to obtain the product.

The material used for low-pressure injection skin can be fabric or polyvinyl chloride fabric. At present, this technology has been widely used in the production of automobile door guards, column guards and parcel frame guards.

3, compared with the traditional process, the advantage lies in

Compared with the traditional coating process, low pressure injection molding process has the following advantages:

1. Low pressure injection molding is the integration of skin material and plastic substrate, there is no possibility of falling off;

2. Low pressure injection molding process because there is no coating process required for the coating process, more environmentally friendly;

3. The internal structure of the low-pressure double-layer injection molding parts can be designed at will, the degree of freedom of the surface modeling is greater than the coating process, and the modeling characteristics are more clear and tough;

4. High production efficiency of low pressure injection molding

In view of the above-mentioned characteristics of low-pressure injection molding, this process has been widely used in the production of automobile door guards, column guards, package frame guards and other products.