Design of Die Casting Mould for Folding Hinge Ring

Time：2020-11-24 11:35:52 / Popularity： / Source：

Essence of pressure casting (referred to as die casting) is to fill cavity of die casting mode with liquid or semi-liquid metal at a higher speed under action of high pressure, obtain castings after forming and solidifying under pressure. It is mainly high-pressure and high-speed filling of die-casting cavity, formed castings have advantages of good quality, high production efficiency, and excellent economic effects. In the end, die-casting parts are no longer in automobile industry and instrument industry, but gradually expanded to machine tool industry, electronics industry, daily hardware and other industries. Special door is fitted on rotating support frame through folding hinge ring. In order to reduce mass production cost, die-casting method is used for molding during production.

1 Introduction of Folding Hinge Ring Parts

Die Casting Mould for Folding Hinge Ring

(A) Front side (b) Back side
Figure 1 Folding hinge ring parts
Shape of folding hinge ring casting is shown in Figure 1. It is mainly composed of a main ring and two rotating support handles. Middle hole of main ring is provided with a polyhedral slot, which is installed in cooperation with rotating shaft. Die-casting material is planned to use YZA1Sil2 alloy. YZA1Sil2 alloy is a typical hard aluminum alloy in aluminum-copper-magnesium series. Its composition is reasonable and overall performance is the best. Alloy is characterized by high strength, certain heat resistance, strict heat treatment process requirements, poor dimensionality, but it can be effectively protected by doping with pure aluminum; it is prone to cracks during welding, and special processes can be used for welding or riveting. .

2 Molding scheme

01 Casting structure characteristics

Figure 2 Casting structure
Structure of casting is shown in Figure 2. Its external dimension is 54mm* 53mm*23mm. During production, cavity layout is set to 2 cavities according to production dimension requirements specified by customer. Maximum outer diameter of main ring is ϕ48mm, outer wall is demolded in two layers, demolding slopes are 3° and 20°respectively. Demolding slopes of upper and lower inner walls are 4° and 3° respectively. In the features of outside of ring, there are two rotating support handles on the left and right, one support handle in the shape of a conical elbow, and one straight rod handle in the shape of a pointed tip. Center of straight shank is perpendicular to center of main ring, and is coaxial with center line of elbow-shaped shank; lower end hole is a counterbore. Upper counterbore has a diameter of 5mm, a depth of 13mm, and a sinker diameter of ϕ3mm, 6mm deep.

02 Mold cavity plate insert layout

Figure 3 Mold cavity plate insert design
1. Compression chamber 2. Diversion cone 3. Moving model core C1, C2. Waterway number
Before designing die-casting mold, cavity plate insert of mold must be designed first, then mold base structure is designed. Design of cavity plate insert is shown in Figure 3. First determine feed position. Two rotating support handles of this part need to be designed with slider molding. When designing runner, first consider position of slider to prevent avoiding slider, so gating position is selected from front without slider. After determining flow direction of melt, use center of the largest outer circle ϕ48mm of part as reference point, and divide feed runner into 3 sections. Inlet of first section of main runner is 18mm wide and 9mm deep; middle section is 8mm wide and 7mm depth; width of runner at the front end of gate is 45mm and 14mm depth, feeds with a slope of 3°. Length of feed channel is divided into 3 sections. Length of runner at the front end of gate is 15mm, middle section of runner is 20mm, and total length of main runner is 30mm.
Size of overflow groove is 10mm*8mm, depth is 13~15mm, demolding slope is 8°~10°, and bottom R3~R5mm transition. In size setting of outer edge of mold cavity plate insert, overflow groove length is 10mm, overflow groove inlet edge is 10mm, exhaust groove length is 15mm, and part center to outer edge of cavity plate insert is set to 65mm to ensure strength of cavity plate insert. Sliders must be installed on the sides of cavity plate inserts, and margin on both sides of slide block is set to 45mm on one side. In cooling of cavity plate insert, distance between C1 and C2 water pipes is 25mm from molded part, remaining space under water pipe is 30mm. Then, based on parting surface as fixed point reference, total thickness of cavity plate insert is 65mm . Because total thickness of cavity plate inserts is not large, and there is no hole in the middle, It adopts straight-through and surrounding point cooling to be set at cavity plate insert, alignment place, and heat gathering place. Depth is 25mm from the deepest surface of cavity, which can be machined by cavity plate inserts, and hardness is high, which can slow down occurrence of thermal cracks at molded parts of two rotating support handles and extend mold insertion.

3 Mould structure

01 Fixed mold design

Figure 4 Fixed mold design
1. Compression chamber 2. Fixed template 3. Fixed mold cavity plate insert 4. Inclined guide column 5. Locking block 6. Protection column
When designing, first calculate side width of pressure chamber 1. Diameter of pressure chamber 1 is ϕ130mm, center offset distance is 45mm, and side margin is 40mm. At that time, width of unilateral template of pressure chamber 1 is initially set to 175mm. Separation of pressure chamber 1 requires layout of two side slide mechanisms. Core pulling distance of side slide mechanism is 45mm, cavity is a 2-cavity layout, and other side length of fixed mold is 210mm to ensure 2-cavity Layout. When designing thickness of final shape, consider: ①Depth of pressure chamber 1, which is set to depth of press ring of 20mm, and second step of pressure chamber ring thickness is 25mm; ②Water pipe of fixed mold cavity plate insert is connected from fixed mold plate, groove depth of fixed mold frame is 50mm, and bottom margin is 40mm, so thickness of fixed mold plate is 90mm. Diameter of 4 guide posts is ϕ35mm, and final dimension of mold plate is 420mm*350mm*90mm.

02 Moving mold design

Figure 5 Design of moving mold push plate
1. Movable mold plate 2. Movable cavity plate insert 3. Push plate 4. Spacer 5. Slider molding insert 6. Slider 7. Slider back seat 8. Protective column 9. Diverter cone S1. The first slider mechanism S2. Second slider mechanism S3. Third slider mechanism S4. Fourth slider mechanism
Overall structure of movable mold is shown in Figure 5. Design of thickness of movable mold 1 is calculated as follows: first, thickness of mold cavity plate insert 2 is 65mm, and then according to strength requirements, at the bottom of movable mold plate frame, bottom thickness is set to be twice thickness of movable mold cavity plate insert 2. After taking integral, total thickness of movable mold plate 1 is 200mm. Setting height and width of cushion block 4: width of mold frame on movable mold plate is 125mm, cushion block 4 should be wider than mold frame side, so that force of movable mold cavity plate insert 2 can be dispersed on cushion block 4. Setting of moving distance of movable mold: casting distance is 53mm, thickness of push plate 3 is 40mm, covering thickness is 30mm, bottom gusset is 15mm, margin is 10mm, and total movement distance is 150mm.
Distance between two ends of push plate 3 and cushion block is 5 mm, two push plate support columns are provided. Part of material in the middle of cushion block 4 is removed by machining, and weight is reduced by digging. Final template size is 420mm*350mm*90mm, and size of movable mold plate is 420mm*350m*200mm. Mold plate materials are all made of #45 steel.
Mold has a structure of 2 cavities, and 4 slider mechanisms are required. In the design of slider 6. Since slider molding inserts of two rotating support handles of part are not large, width dimension of slider back seat 10 is set to be 5mm larger on one side than support handle slider forming insert, and then they are made into one body. When designing height of slider 6, it is necessary to consider core-pulling stroke and set it to 45mm.

Figure 6 Mold installation
1. Compression chamber 2. Diverter cone 3. Moving model core 4. Moving model cavity plate insert 5. Fixed template 6. Inclined guide column 7. Locking block 8. Slider 9. Slider molding insert 10. Slider Rear seat 11. Movable template 12. Push rod fixed plate 13. Push plate 14. Support column 15. Reset rod 16. Push rod 17. Limit block 18. Spacer 19. Protection column
Other accessories such as layering, wear-resistant plates, etc., need to be quenched. Length of slider 6 is designed to be 135mm, oblique guide post has an oblique guide angle of 20°, and slider mechanism with a 23° inclination of locking surface of locking block is installed on both sides of mold, as shown in Figure 6.

4 Precautions for die casting mold installation

During use of mold, following points should be noted.
(1) Check whether length of putter used is appropriate, whether length is same, number of putters used is more than 4, and they are placed in regular putter holes.
(2) Mold must be installed with a reset rod. Push rod must be returned after it is pushed out, otherwise mold cavity plate will be damaged. Correctly connect oil pipe and control switch circuit, confirm that metal of conductive part is not exposed, and select control program to operate.
Folding hinge casting has a complex shape, with 3 side holes on both sides, combined with molding needs of casting, a two-plate die-casting mold with 2 cavities is designed for die-casting. When pouring, melt enters cavity from one side. Molding of 3 side holes on casting uses 2 inclined guide column side core-pulling sliders for core-pulling and demolding, fixed mold side is provided with a slider locking block to lock slider to prevent slider mold from opening during die casting. After mold, casting is left on movable mold core, and push rod is used to realize automatic demoulding of casting. Actual production shows that mold structure design is reasonable and quality of formed castings is good. It is feasible to provide a reference for mold design of similar castings.

Gud Mould Industry Co., Ltd