Headphone jack connector molding design
Time：2020-02-20 14:49:06 / Popularity： / Source：
1 Plastic parts analysis
Figure 1 Headphone jack connectorFigure 1 shows structure of a mobile phone headphone jack connector, external dimensions are 15mm*φ5.7mm, dimensional accuracy requirements are high, most of dimensional accuracy is ±0.02mm, material is PA46 + 30% GF, shrinkage rate is 0.3% . Plastic part has a complicated structure, shape has many undercut and convex structures, inside is a cylindrical structure, so it is necessary to consider placement of molded plastic part in mold to facilitate parting and demolding.
2 Parting and molded parts design
2.1 Classification designSince shape of plastic parts has more concave and convex structures, size is small, melt filling is difficult, easy to trap and lack of material, mating surface is easy to generate flash, and precision of plastic part is high, so parting surface design is difficulty in molding design. Conventional parting surface design is shown in Fig. 2. This design requires a large space for placement, flashing of plastic parts on parting surface is difficult to control, core forming of concave and convex structures of outer shape is also difficult to achieve, as shown in Figure 3.
Figure 2 Conventional parting surface design
Figure 3 Problems with conventional parting surface design
Figure 4 Plastic parts placement
Figure 5 main parting surface designIn order to make rational use of mold space and better shape, plastic parts to be molded are changed to be placed horizontally, main parting surface is divided from the largest projected area of plastic parts (see horizontal line of Fig. 4), middle cylinder is formed by lateral core pulling, side concave and convex structures are formed by fixed mold oblique core pulling. Due to small size of plastic parts, mold adopts a 8-cavity structure, main parting surface is shown in Fig. 5.
2.2 molded parts design
Figure 6 cavity plate
Figure 7 coreMolded parts are main parts of shape and size for molded parts inside and outside. Cavity plate is shown in Figure 6, and core is shown in Figure 7. Since shape of plastic part is more concave and convex, integral core design cannot be adopted, core needs to be divided into a plurality of small core inserts, which is convenient for demoulding and processing. Cavity plate needs to adopt a fixed-die oblique core, so cavity plate is also divided into a plurality of inserts, including one large insert and two oblique cores.
3 Core design
Figure 8 fixed mold oblique slider core
Figure 9 Fixed mold slider core distanceIn order to rationally utilize space and better control molding quality of plastic parts, according to above analysis, position of plastic parts is designed, fixed part of plastic part is cored by oblique core pulling mechanism, as shown in Fig. 8, oblique core angle is 60°. Outer surface structure of plastic parts is shallow, and distance between oblique cores is about 0.02mm. Therefore, it is only necessary to use spring to open 2mm (2/sin60°≈2.31mm, core distance meets requirements) when mold is opened, so that fixed mold is inclined. Pull out buckle to core pulling mechanism, as shown in Figure 9. Fixed mold oblique core pulling is design difficulty of mold. This design can make rational use of overall space of mold, so that mold structure is more compact, and at the same time meet requirements of fixed mold oblique core pulling.
Figure 10 Dynamic mold slider coreInner hole of earphone jack connector is formed by a side core, and inclined guide column core pulling mechanism is designed in movable mold, as shown in FIG. Mold is a 8-cavity structure, and one large slider is used for core pulling at the same time. In order to ensure sufficient core pulling force and core balancing, a double inclined column is used for core pulling, wherein oblique guide column has an inclination angle of 25°, diameter is φ12mm, length of inclined guide post is 65mm, and distance from plastic core to core is 10.75mm. It has been verified that 65×sin25°≈27.5mm, 27.5mm>10.75mm, inclined guide column core meets core distance requirements of plastic parts.
4 Gating system design
Figure 11 Gating system design
Figure 12 Filling Mold flow AnalysisGating system is mainly composed of main runner, sub runner, gate and cold hole. Mold is a 8-cavity structure. In order to ensure balanced feeding, a flip flow passage structure is adopted, as shown in Fig. 11, wherein split flow passage adopts a trapezoidal and semi-circular combined structure with a radius of R1.5 mm. Mold flow analysis shows that casting system can meet injection molding requirements, as shown in Figure 12.
5 Cooling system design
Figure 13 Cooling line arrangementIn order to ensure production efficiency and cooling effect, a cooling pipe is designed on movable plate, fixed plate and support plate of mold, diameter is φ8 mm, as shown in FIG.
6 Mold working principle
Figure 14 mold structure1. Movable seat plate 2. Support plate 3. Push plate 4. Push rod fixing plate 5. Backing plate 6. Guide bush 7. Fixed mold seat plate 8. Guide post 9. Fixed mold fixing plate 10. Fixed template 11. Slanting guide column 12. Slider core 13. Moving plate 14. Reset rod 15. Draw button 16. Push plate guide post 17. Push plate guide sleeve 18. Limit screw 19. Spring 20. Fixed mold core block 21 Fixed mold core insert 22. Push rod 23. Pull rod
Figure 15 mold working classification principleMold structure is shown in Figure 14. Working principle of mold is as follows: first, injection molding machine is opened, main parting surface 2 of movable template and fixed template are locked by pull lock, but parting surface 1 between fixed mold plate and fixed template is bounced 2mm under action of spring (see Figure 15(a)), fixed-die oblique core pulling mechanism pulls out buckle; when fixed mold touches limit nail, die buckle is pulled open, parting surface 2 is opened (see figure 15(b)), movable mold side slider is finished by fixed mold inclined guide column. After slider of injection molding machine moves to a specified distance, pusher of injection molding machine pushes push rod to push out aggregate in plastic part and runner; push rod is reset under action of spring, and next injection is closed.
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