Structural Optimization of Progressive Die for Upper Hinge Screw Mounting Plate_Hinge Knowledge_Tall

Fig. 1 showcases the upper hinge screw mounting plate made of DCOI, a material with 10% carbon content, a tensile strength of 270 MPa, a yield strength range of 130-260 MPa, and 28% elongation after fracture. The original forming process had several issues such as operational hazards, low work efficiency, high machine tool occupancy rate, and unstable part quality. In order to address these problems, an optimized forming process was developed, utilizing a three-position progressive die design to ensure safe production, improve efficiency, and reduce costs. This article will provide an expanded analysis of the parts forming process, layout design, mold structure, and key mold part design in detail.

Parts Forming Process Analysis:

The upper hinge screw mounting plate has a simple and symmetrical shape, involving three processes: blanking, punching, and bending. The tolerance grades of the 90.15mm holes and center distance of 2 holes (820.12mm) are ITIO and IT12 respectively, while the rest of the dimensions do not require specific tolerances and can be achieved through ordinary stamping. The material's thickness of 3mm ensures better plasticity, and the height of the straight edge to be bent is 9mm. Controlling springback during bending is crucial. To achieve this, the mold design must ensure the bending line is perpendicular to the fiber direction, with the burr surface on the inner edge of the bending compression.

Layout Design:

The expanded dimensions of the part are 110mm x 48mm, with the longitudinal dimension being relatively large. To simplify mold manufacturing and reduce costs, a single-row method is employed. Several factors were considered during the layout design:

1. Accurate and reliable positioning: Two 90.15mm holes are utilized as the second and third positioning and guiding process holes to minimize cumulative errors.

2. Simplification of mold structure: The part's shape is punched out in two steps to facilitate manufacturing and enhance mold service life.

3. Sturdy material feeding: A double-sided carrier layout design with sufficient strength and rigidity ensures safe and stable feeding of parts during the manufacturing process.

4. Reduction of cumulative error: The number of stations is minimized while maintaining die strength. Only three necessary stations for punching, forming cutting, and bending are arranged to enhance precision.

Based on the analysis, a compact single-row arrangement with a double-sided carrier is adopted, as shown in Fig. 3. The strip width is 126mm, with a 7mm edge. The step distance is set at 55mm. The process includes punching two 90.15mm holes, die-cutting shape waste, and bending and punching both sides of the carrier.

Mold Structure Design:

The mold structure, as depicted in Fig. 4, possesses several key features:

1. Sliding intermediate guide post precision formwork: The mold operates under dual guidance, improving accuracy, relative position, and facilitating assembly and maintenance.

2. Use of limit columns: These columns ensure consistent positioning of the upper die, maintaining stability, and parallelism between the unloading plate and upper and lower die bases.

3. Feeding guide: A single-side material guide plate and material guide block facilitate safe feeding of process parts, with precise positioning using rear straight edge and positioning pins.

4. Simplified structure and reduced material usage: Bending-forming and cutting carriers are designed at the same station, with rounded and sharp edge structures separating the carrier.

5. Integration of elastic unloading and top piece devices: These devices allow for compressed state separation and formation of strips, controlling springback, and ensuring part quality.

Design and Manufacture of Key Mold Parts:

The mold's key parts, including the die, punching punch, shape punching punch, bending-separating punch, and other templates, have high precision requirements. The die adopts an integral structure with Cr12moV material and HRC hardness between 60-64. Wire cutting is employed to achieve dimensional tolerance, and the unilateral matching gap between the punch and die is controlled at 0.12mm. The punching punch employs a step fixing form, while the shape punching punch and bending-separating punch adopt straight-through structures. High precision is maintained in all parts.

After more than a year of practice, the optimized progressive die for the upper hinge screw mounting plate has proven to be effective in ensuring stable part quality, simple and safe operation, high production efficiency, and convenient maintenance. The mold structure exhibits high accuracy and repeated assembly precision, meeting the requirements of mass production. Tallsen's manufacturing process incorporates advanced production concepts and fine technology, ensuring excellent performance, durability, safety, and convenience in their products.