Sharing of design of injection mold for car window trim
Time:2025-04-23 07:52:25 / Popularity: 53 / Source:
1 Plastic part structure
Inner surface of automobile glass window decorative panel has 4 buckles, and opening direction is shown by arrow in Figure 1. Structure of plastic part is shown in Figure 2. Outer dimensions are 411mmx203mmx37mm, wall thickness is 4mm, and outer surface is slightly arched. In order to increase sealing of glass window and prevent water leakage, a reinforcing rib is set inside buckle position ①, and height of reinforcing rib is 1mm; in order to prevent outer surface corresponding to root of buckle position ① from shrinking, a material reduction groove is set at root of buckle position ①, wall thickness of buckle position root is only 1mm, angle between side and bottom of material reduction groove is 50°. Distance between reinforcing rib and material reduction groove is relatively close. Due to obstruction of reinforcing rib, slider cannot be demolded along V1 direction, and due to obstruction of side wall of material reduction groove, it cannot be demolded along V2 direction, can only be demolded along opening direction of material reduction groove (V3 direction). Due to small size of buckle position, cross-sectional size is only 28mmx18mm, and it is impossible to design two independently running slider demoulding. For this structure, a slider linkage demoulding mechanism is designed in which large slider drives small slider to move.

2. Mold structure
2.1 Linkage slider mechanism
Linkage slider mechanism is mainly composed of a large slider, a small slider, an inclined wedge, a slider seat, a spring, a blocking block, a blocking bar, a T-shaped guide rail, a limiting column, a guide block, etc. Structure is shown in Figure 3.
1. Locking block 2. Angle wedge 3. Slider seat 4. Block block 5. Spring 6. Block bar 7. Fixed mold plate 8. Fixed mold insert 9. Small slider 10. Limiting column 11. Large slider 12. Moving mold insert 13. Moving mold plate 14. T-shaped guide rail 15. Guide block
Upper surface of large slider is an inclined surface. When mold is opened, small slider 9 slides on upper surface of large slider 11. Two mechanisms are set inside linkage slider mechanism: ① A spring 5 is set between slider seat 3 and small slider 9, and small slider 9 is pushed away from slider seat 3 by elastic force of spring 5; ② A blocking block 4 is set on fixed mold plate 7, and a blocking bar 6 is set on small slider 9. Blocking bar 6 and small slider 9 are fixed with screws. Contact surface between blocking block 4 and blocking bar 6 is a vertical surface. In initial stage of mold opening, inclined wedge 2 drives large slider 11 to move laterally, and blocking block 4 moves upward with fixed mold plate 7. Blocking block 4 will prevent small slider 9 from moving laterally and push small slider 9 away from slider seat 3. Above two mechanisms can make small slider 9 slide on upper surface of large slider 11. Upper surface of large slider 11 is an inclined surface, and an inclined T-shaped guide rail 14 is set on upper surface of large slider 11. When small slider slides along upper surface of large slider, T-shaped guide rail will cause small slider to move in vertical direction.
In order to make small slider move along opening direction of material reduction groove, a guide block is set at each end of small slider. Guide block structure is shown in Figure 4, and buckle position of end face of small slider is shown in Figure 4(c).
Upper surface of large slider is an inclined surface. When mold is opened, small slider 9 slides on upper surface of large slider 11. Two mechanisms are set inside linkage slider mechanism: ① A spring 5 is set between slider seat 3 and small slider 9, and small slider 9 is pushed away from slider seat 3 by elastic force of spring 5; ② A blocking block 4 is set on fixed mold plate 7, and a blocking bar 6 is set on small slider 9. Blocking bar 6 and small slider 9 are fixed with screws. Contact surface between blocking block 4 and blocking bar 6 is a vertical surface. In initial stage of mold opening, inclined wedge 2 drives large slider 11 to move laterally, and blocking block 4 moves upward with fixed mold plate 7. Blocking block 4 will prevent small slider 9 from moving laterally and push small slider 9 away from slider seat 3. Above two mechanisms can make small slider 9 slide on upper surface of large slider 11. Upper surface of large slider 11 is an inclined surface, and an inclined T-shaped guide rail 14 is set on upper surface of large slider 11. When small slider slides along upper surface of large slider, T-shaped guide rail will cause small slider to move in vertical direction.
In order to make small slider move along opening direction of material reduction groove, a guide block is set at each end of small slider. Guide block structure is shown in Figure 4, and buckle position of end face of small slider is shown in Figure 4(c).
A 50° inclined surface is set on guide block, and inclined surface is consistent with inclination of material reduction groove. A buckle position is set at each end of small slider, and buckle position matches guide block. When opening mold, small slider slides along T-shaped guide rail on upper surface of large slider toward opening direction of material reduction groove under action of inclined surface of guide block, so that buckle position and material reduction groove are demolded. When closing mold, buckle position of guide block can fix position of small slider in mold to prevent small slider from moving closer to center of mold. Movement process of linkage slider: Since height of vertical surface of blocking block 4 is 45mm, when mold opening distance is 0~45mm, inclined wedge 2 leads slider seat 3 and large slider 11 to move in horizontal direction, blocking block 4 and spring 5 push small slider 9 away from slider seat, so that small slider 9 slides on upper surface of large slider 11. Upper surface of large slider 11 is an inclined surface. A T-shaped guide rail 14 is provided on upper surface of large slider 11. Under action of T-shaped guide rail 14, small slider 9 will move vertically downward. Under guidance of guide block 15, small slider 9 moves along 50° inclined surface of guide block to demold reinforcing ribs and material reduction groove. When mold separation distance is 45mm, blocking block 4 is out of contact with blocking bar 6. At this time, reinforcing ribs and material reduction groove have been completely demolded. Driven by limit column 10 on upper surface of large slider, small slider 9 follows large slider 11 to perform demolding movement in horizontal direction until buckle position ① is completely demolded. When mold is closed, movement process of linkage slider is just opposite.
2.2 Combined oblique push mechanism
Opening of buckle position ② faces inside of plastic part, and an oblique push mechanism is used for demoulding. Since size of buckle position ② is 10mmx7mmx331mm, cross-section is small, and its length is long. In order to strengthen rigidity of oblique push block and prevent deformation, cross-section of oblique push block needs to be enlarged, and cross-section of oblique push block is designed to be 46mmx63mm, as shown in Figure 5(a). Oblique push mechanism adopts a combined structure, which consists of an oblique push block, an oblique push sleeve, an oblique push rod, a reinforcing rod, and an oblique push seat, as shown in Figures 5(b) and (c). Oblique push block is large in size and is supported by two oblique push rods to keep oblique push block balanced during movement. Interior of oblique push rod is a hollow tube that can be connected to waterway. In order to prevent oblique push rod from being deformed due to excessive force, a reinforcing rod is set next to oblique push rod, and reinforcing rod bears twisting force during pushing out. In order to set up a cooling water circuit inside push mechanism, push rod is connected to inlet and outlet water pipes, and a push sleeve is installed on push rod to prevent wear.
1. Push block 2. Push sleeve 3. Push rod 4. Push seat 5. Inlet and outlet water pipes 6. Reinforcement rod
2.3 Rack-type inclined push mechanism
Inclined push mechanism is used to demould buckle position ③. Since demoulding angle of buckle position is large (70°), it is easy to get stuck if inclined push rod is directly pushed by inclined push seat. A rack-type inclined push mechanism driven by a spur rack is used, as shown in Figure 6(a). An inclined rack is designed on inclined push rod and spur rack is fixed on push plate. Inclined push seat has two guide grooves, as shown in Figure 6(b), one of which is a vertical groove to guide movement of vertical rack; the other is an oblique groove to guide movement of oblique push rod. When opening mold, push plate pushes spur rack upward, and then spur rack pushes oblique rack upward to demould buckle position ③.
2.4 Parting surface design
Contour of plastic part is relatively neat, and corresponding parting surface is relatively smooth. Parting surface of mold is a straight surface created by parting lines of two plastic parts. There are no sharp corners or corners on parting surface. One mold and two cavities are used to simultaneously mold left and right glass window decorative panels of car. Without affecting strength of mold parts, movable and fixed mold cores adopt an insert structure. Insert size is 570mm*490mm*84mm, which is large in size and relatively thin in thickness. In order to increase strength and rigidity of insert, prevent deformation of movable and fixed mold inserts, movable and fixed mold inserts are divided into two pieces. Matching degree of parting surface is designed to be 30mm, and remaining parts are designed with a mold clearance of 0.3mm. Volume of plastic part is large, and several exhaust grooves are opened on parting surface to allow air in cavity to be discharged smoothly. Positioning bosses and positioning grooves with a side slope of 5° are set on movable and fixed mold inserts to increase mold closing accuracy of movable and fixed molds, prevent misalignment, as shown in Figure 7.
2.5 Casting system
Automotive glass window decorative panel is an appearance part, and outer surface is required to be free of defects such as gate marks, shrinkage, burning, and weld lines. In order to overcome defects of direct casting with ordinary runners, hot runner is converted to ordinary runners and then side gate is used for feeding. According to manufacturing experience of similar molds, two gates are set at both ends of plastic part to be molded, as shown in Figure 8. After plastic part is assembled on car, two ends are covered by other parts, and gate marks will not affect appearance. In order to facilitate trimming of gate condensate, a fan-shaped gate is used for feeding.
2.6 Cooling system
Different cooling water channels are used according to structure of movable and fixed molds. Fixed mold is suitable for straight-through cooling water channels. Since temperature of hot runner is relatively high, in order to reduce temperature of this area, cooling water channels are arranged densely near hot runner. Fixed mold is divided into 6 groups of independent water channels, represented by A~F, as shown in Figure 9(a).
There are 2 combined oblique push mechanisms, 2 rack oblique push mechanisms and several push rods on movable mold, which are suitable for water-parallel cooling water channels, and water wells are connected by straight-through water channels, which are divided into 4 groups of independent water channels, represented by a~d, as shown in Figure 9(b). In order to make temperature of each part of mold uniform, distance between water channel and cavity is about 15~20mm, and interval between water channels is uniform, about 25~30mm. Due to large size of linkage slider and combined oblique push mechanism, a separate cooling water channel needs to be set.
There are 2 combined oblique push mechanisms, 2 rack oblique push mechanisms and several push rods on movable mold, which are suitable for water-parallel cooling water channels, and water wells are connected by straight-through water channels, which are divided into 4 groups of independent water channels, represented by a~d, as shown in Figure 9(b). In order to make temperature of each part of mold uniform, distance between water channel and cavity is about 15~20mm, and interval between water channels is uniform, about 25~30mm. Due to large size of linkage slider and combined oblique push mechanism, a separate cooling water channel needs to be set.
3 Mold structure
Mold is designed as a 2-cavity layout, with 2 plastic parts placed opposite to each other. 2 large slider mechanisms are installed on both sides of mold, and 2 oblique push mechanisms are arranged opposite to each other. Both oblique push mechanism and slider mechanism adopt a combined structure. When mold is opened, forces of 2 slider mechanisms and 2 oblique push mechanisms are balanced with each other. Mold structure is shown in Figure 10.
Among them, locking block 7, slider seat 8, blocking block 9, blocking bar 10, small slider 18, large slider 19, and oblique wedge 20 form a linkage slider mechanism, slider 30 and oblique guide column 31 form an oblique guide column + slider demoulding mechanism of buckle position ④. Large oblique push rod 23, small oblique push rod 25, pull rod 32 and all push rods 22 are ejection mechanism of mold. After injection is completed, movable mold and fixed mold part are separated at contact surface of movable mold plate 6 and fixed mold plate 11. When movable mold is separated from fixed mold, following two mold opening actions are performed simultaneously: one is that inclined guide column 31 guides slider 30 to perform lateral demolding movement; the other is that inclined wedge 20 guides linkage slider mechanism to perform demolding movement. When injection molding machine ejector leads movable mold part to move to limit position, injection molding machine ejector pushes ejection mechanism to perform demolding movement. After plastic part is ejected, injection molding machine ejector drives the mold ejection mechanism to reset together. When reset is completed, injection molding machine ejector pushes mold to start mold closing, and following three actions are performed simultaneously: ① Tightening block 29 and inclined guide column 31 guide slider 30 to reset; ② Inclined wedge 20 guides linkage slider mechanism to reset; ③ Reset rod 24 guides ejection mechanism to reset. When mold is completely reset, next production cycle begins.
Among them, locking block 7, slider seat 8, blocking block 9, blocking bar 10, small slider 18, large slider 19, and oblique wedge 20 form a linkage slider mechanism, slider 30 and oblique guide column 31 form an oblique guide column + slider demoulding mechanism of buckle position ④. Large oblique push rod 23, small oblique push rod 25, pull rod 32 and all push rods 22 are ejection mechanism of mold. After injection is completed, movable mold and fixed mold part are separated at contact surface of movable mold plate 6 and fixed mold plate 11. When movable mold is separated from fixed mold, following two mold opening actions are performed simultaneously: one is that inclined guide column 31 guides slider 30 to perform lateral demolding movement; the other is that inclined wedge 20 guides linkage slider mechanism to perform demolding movement. When injection molding machine ejector leads movable mold part to move to limit position, injection molding machine ejector pushes ejection mechanism to perform demolding movement. After plastic part is ejected, injection molding machine ejector drives the mold ejection mechanism to reset together. When reset is completed, injection molding machine ejector pushes mold to start mold closing, and following three actions are performed simultaneously: ① Tightening block 29 and inclined guide column 31 guide slider 30 to reset; ② Inclined wedge 20 guides linkage slider mechanism to reset; ③ Reset rod 24 guides ejection mechanism to reset. When mold is completely reset, next production cycle begins.
1. Moving mold base plate 2. Pad 3. Push plate limit column 4, Push plate 5. Push rod fixing plate 6. Moving mold plate 7. Locking block 8. Slider seat 9, Block block 10. Yang block 11. Fixed mold plate 12. Hot runner plate 13. Fixed mold base plate 14. Insulation plate 15. Hot runner electrical components 16. Positioning ring 17. Fixed mold insert 18. Small slider 19. Large slider 20. Wedge 21. Moving mold insert 22. Push rod 23. Large inclined push rod 24, Reset rod 25, Small inclined push rod 26. Moving mold insert inclined wedge 27. Fixed mold insert inclined wedge 28. Hot runner nozzle 29. Wedge block 30. Slider -31. Oblique guide column 32, Pull oblique rod 33. Push plate
Recommended
Related
- Introduction to two-color injection molding technology and mold features05-14
- Learn about commonly used plastic additives in one article!05-13
- Design of automatic demoulding mechanism for external thread of automobile dashboard05-12
- What are key points for checking mold drawings?05-09
- Influence of injection mold temperature on process05-08