In the production of auto parts, dashboards are one of the most common auto parts requirements. Nowadays, the design of automobile dashboards is mostly produced by plastic manufacturing. With the development of automobiles in terms of safety and environmental protection, people’s requirements for safety and environmental protection of automobile trims are also increasing; at the same time, more and more dashboards of car dashboard manufacturing company adopt the appearance design of seamless airbag doors, which puts forward higher and higher requirements on the manufacturing process of the dashboard.
What are car dashboards made of? Take Chevrolet’s dashboard as an example. The total weight of the dashboard system is about 17KG. Its component structures mainly include: dashboard body, airbag frame, dashboard lower body, sub-instrument panel body, interior trim panel, decorative panel, wind pipe, mobile ashtray; main car dashboard material: general-purpose plastic PP+EPDM-T20, PP-T20, ABS, PC+ABS, HDPE; engineering plastic PA+30GF%, POM, etc., based on a rough calculation, the amount of modified PP accounts for 80% of the plastic used in the dashboard. If you want to improve the product quality of the car dashboard, you must pay attention to the car dashboard manufacturing process of small volume manufacturing in automotive industry.
The dried plastic particles are cut in the injection molding machine through the screw and the barrel is heated and melted and then injected into the instrument panel mold to cool to obtain the finished product. Used to manufacture rigid plastic instrument panel body, blister and soft instrument panel skeleton and most other related parts. Hard plastic instrument panel materials mostly use PP, and the materials of instrument panel skeleton mainly include modified materials such as PC/ABS, PP, PPO (PPE). For other parts, ABS, PVC, PC, PA and other materials that what car dashboard made of are selected according to different functions, structures and appearance requirements.
The injection molding processing of the instrument panel can be further divided into: gas-assisted injection molding, sequence valve injection molding, compound injection molding, insert injection molding, two-color injection molding, two-shot injection molding, etc.
- Gas-assisted injection molding
Gas-assisted injection molding is an injection molding process in which molten plastic particles are injected into the mold while a certain amount of inert gas is injected, and a specific area of the part is formed into a hollow structure through the design of the gas path, structure and process control. The hollow structure not only enhances the mechanical properties of the parts, but also reduces the wall thickness of the parts, improves the appearance of the parts, and reduces the material cost and forming cycle.
- Sequence valve injection
Through the valve interlocked with the equipment, the opening and closing of different gates of the mold hot runner are controlled to control the injection molding process of the material flow. This process is suitable for thin-walled and long-process products, reduces the requirements for the clamping force of the equipment, optimizes the surface quality, and shortens the forming cycle.
- Composite injection
Place a sheet that matches the shape of the mold or a shapeless sheet on the side of the movable mold of the injection mold, and then injection molding, so that the product has a two-layer structure while using the mold to give the shape. The advantage of sheet metal fabrication services is that the processing procedures are reduced, the product appearance is good, and the adhesion between parts is strong.
- Instrument panel insert injection molding
It is more popular in the home appliance industry, and this process is used in the manufacture of electrical switches in the production of instrument panels. It is to place the metal parts that need to be embedded in the injection molded parts in the mold before injection molding, and the molten plastic after injection molding partially wraps them into parts.
- Two-color injection molding for dashboard
On the two-color injection molding machine, different colors/types of raw materials are injected into the special injection mold at the same time/sequentially in the same production cycle, so that the product has different appearance/performance, but it is gradually being repaced by the two-shot molding because of the huge investment in equipment and molds.
- Double injection of instrument panel
Over-injection is an insert injection where the injection part is an insert. It is mainly used for parts with high mechanical performance and appearance requirements. Injection molding materials selection is the key to this process.
With the continuous exploration of the automotive industry in the research and development of vacuum casting applications, instrument panel materials and process improvement, automotive instrument panels will gain more and more beautiful and ergonomic appearance and experience design.
Car Dashboard Mold Design Highlight
Due to the large size of the plastic part, the cavity is arranged one out and one eccentrically. The mold block is the standard mold block CH5565. The front and rear of the mold cores are positioned and locked by extrusion blocks. Positioning pins are added between the B plate of the moving mold, square iron, and bottom plate to maintain the rigidity of the mold.
The area of plastic parts is large and the molten plastic process is long, so the design of the gating system is very essential. Considering that there are many bones and holes in plastic parts, there are many factors affecting the flow of molten plastic and large filling resistance. Therefore, the gating system is designed with a 3-point latent gate, which is located on the same side of the plastic part. The runner pull pin is designed with a tapered pull pin to facilitate the manipulator to grasp the material at the water intake.
The ejector system of plastic parts adopts an ejector pin and cylinder ejector. In order to make the ejection system smooth, some innovative designs have been made. The middle support guide pin is designed, which is guided by graphite middle support. The top of the middle support guide pin is fixed on the back of plate B with locating pins, and the bottom is fixed on the moving mold plate with screws. The design of the middle support guide pin has the best guiding performance and overcomes the disadvantage of the poor verticality between the traditional middle support guide pin and the thimble plate.
At the same time, the middle support guide pin can also act as a support head. For the convenience of mold installation, M10 threaded holes are designed on the end face of the return needle to tighten the thimble plate. At the same time, limit screws are designed on the thimble plate, and positioning pins are designed on the top of the support heads. All thimbles adopt Japanese Misumi high-speed steel thimble SKH51.