this is an automotive door trim panel injection mould for our European customers which is made at 2019 years. our clients are professinal automotive plastic injection molding companies with 14 plants for the interior and exterior car trim part with global presence included China. we had worked together for more than one year, and Asia Billion already send them more than 10 sets big moulds which looks like this one.
automotive injection mold
Core surface finish:
600# sandpaper polishing
Cavity surface finish:
No of Cavities:
1 x 1
Type of gating:
SVG Valve gate and edge gate
ejector pin+ejector block +lifter
Slider and lifter material:
H13 with heat treatment
Lead time for T1
Mold base steel:
300 000 cycles
Place of Origin
1) large size mold up to 1.5 meters
2) 11 lifters with slider for the click features
3) Hight technology SVG hot runner for the injection molding
4) Mold trial is done at the 1000 tons injection molding machine
Here Asia Biilion would like to tell you our experience and insights for this project as a story for your reference.
Automobile door panels are an important part of automobile interior parts. They are located on the inner side of automobile doors. This case is a car's left rear door panel, which is used to illustrate the design points and experience of automobile door panel injection molds.
The material of automobile door panels is PP + EPDM, and the shrinkage rate is generally 1.011. EPDM rubber has excellent resistance to ozone, heat and weathering, and can improve the elasticity of door panels. The external dimensions of the door panel are: 880 × 670.4 × 105.6mm.
Mold gating system:
The 3-point SVG hot nozzle is used to turn the cold runner gating. The 3 SVG hot nozzles are not filled at the same time for injection molding, but they are controlled by sequential valves. The filling effect is opened sequentially according to the mold flow analysis and real production molding status.
Product surface requirements:
Pattern finishing. The appearance of the surface should be at least 5 degrees, and there should be no defects such as gate marks, welding line and shrinkage.
Mold flow analysis:
The door panel of the car is an exterior part. Welding lines are not allowed. When injection molding, we need to drive the welding line to the non-appearing area or eliminate the welding line. By using a 3-point SVG hot runner system, the oil cylinder or air cylinder is used to control the 3 hot nozzle Open and close to achieve the effect of injection molding without welding lines.
The mold parting line lock position is designed on the fixed moving mold. The fixed moving mold is surrounded by four sides with draft angle of 5 °, and the four sides are made of wear-resistant blocks. This four-sided design method is used on automobile door panels and fenders. First, add 50mm space from the largest edge of the plastic part. In the design principles of automobile molds, 30mm space for small molds (within 5050), 40mm space for medium molds (5050-1010), and 50mm space for large molds (over 1010). Add 50-70mm extra space (In the design of automotive molds, only the sealing position cooperates, and the rest are completely avoided to reduce the workload of the mold fit. The avoidance space is also an area to ensure the strength of the mold.) In this way, it is designed to meet customer mold Strength requires cost-saving molds at the same time. Due to the large injection pressure, the movable mold needs to be thickened accordingly to ensure the strength of the mold. In short in the daily design, according to different customer requirements and flexible use of the factory, design molds that meet customer needs and save costs.
Mold structure design:
The side core lifting is the core mechanism of the automotive door trim panel injection mould. There are 11 side core lifting mechanisms in this mold, which are S1 to S11. Among these 11 lateral core-pulling mechanisms, S11 adopts the structure of angle pin + slider, and the limit of the slider adopts a structure in which a limit clamp and a stopper are used in combination, which is safe and reliable. S1 to S10 all adopt the lifter structure.
In the structural design of the lifter, the lifter angle pin push rod should not exceed 12 °. The design of the lifter should prevent the plastic part sticking when demolding, which will cause the plastic part to deform and crack.
Mold positioning and guidance design:
The periphery of the mold base is positioned with a square guide block instead of a round guide pin. The reason is that the size of the mold blank can be made smaller, and the structure is more compact. If round guide pins are added at the four corner positions of the mold, the current mold size is not enough, and the size will be increased, which will inevitably increase costs. In addition, the square guide block need to be positioned by pins, and the wear surface is designed for the matching surface, which is convenient for machining and fitting.
Mold ejection design:
The mold ejector plate is ejected with 4 powerful nitrogen springs, and the product is ejected with ejector pin + ejector block + lifter ejector. The maximum diameter of the ejector pin is 16mm and the minimum is 8mm.
Design of mold cooling system:
The design of the temperature control system has a great impact on the molding cycle time of the mold and the quality of the product. It is especially important for injection molds for automotive door panels with high appearance requirements. One of the design principles of the cooling water channel is that the distance from the cavity surface should be approximately equal, so that the temperature of the mold cavity is roughly balanced. The temperature control system of this mold adopts the combination form of "straight-through water line + lifter water line + water well". This combined form is preferred to use straight-through water line, supplemented by lifter water lines, and water wells must be used as a last solution. Its advantages are uniform cooling of plastic parts, short molding cycle and high molding quality, which are suitable for molds with high requirements and high appearance performance requirements.
Automotive door trim panel injection mould belongs to large injection mold. The square guide block, precise positioning, and four-sided surrounding positioning design are the characteristics of automobile door panel injection molds. In the early stage of the mold design of Asia Billion, mold flow analysis software was used to assist the design. It successfully analyzed the filling, temperature, time, shrinkage, deformation, weld marks, cavitation, etc. of the plastic parts, and we reference many previous similar project design and manufacturing experience. Many problems were avoided when designing the mold. The successful mold trial to mass production proves that it is reasonable in design.
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