Metal Stamping Die
Metal stamping dies have various applications, and each industry also has many types of products. Different products correspond to different stamping molds made of different materials, which are usually used for small batch products.
Progressive Stamping Die Design
The progressive stamping die design is complex. progressive stamping die are manufactured using a punching machine, with main designs including punching design, bending design, forming design, and deep drawing design. The advantage of stamping is that it can produce a large number of identical workpieces in a short period. Reasonable design of dies is beneficial for improving the quality of custom stamping die. If the design is unreasonable, it will cause unnecessary problems to the die.
Material Requirement for Progressive Stamping Die Design
The selection of materials for progressive metal stamping die requires consideration of various factors, such as application environment, workpiece requirements, die structure, and die performance. Choosing suitable materials can help increase the die’s usage time and product quality, further improve production efficiency, and reduce the waste of materials. The materials used in stamping and stamping design have a mutual influence, and their properties directly affect stamping process design, stamping part quality, and product usage time.
Due to different usage requirements, the selection of stamping materials also varies. However, from the perspective of stamping technology, to ensure that the stamping process can be completed with high quality, the stamping material should also meet the requirements of the stamping process. When selecting stamping materials, the first thing to consider is the product’s usage requirements. In general, for the main stamping parts on the machine, the selected materials need to have high strength and stiffness characteristics; Materials with high conductivity and magnetic properties will be used to make some stamped workpieces on electrical appliances; High-strength materials will be used to make stamping parts for cars and airplanes, and the application of this material is to minimize weight as much as possible; Materials with extremely high corrosion resistance will be used to make stamped parts on chemical containers.
The requirements for materials used in progressive stamping die design are as follows:
- The Thickness Tolerance Meets the Requirements
The different thicknesses of various materials determine the gap between the stamping punch and the die, so the material thickness tolerance range must comply with the national standards. The smaller the thickness tolerance, the higher the precision of the product. If the thickness tolerance is too large, it will have some impact on the quality of the workpiece. In severe cases, it may cause damage to dies and equipment.
- Has a Good Stamping Performance
Stamping performance refers to the adaptability of sheet metal to various stamping processing methods. Stamping processing is a metal plastic processing method, therefore, it requires materials to have good plasticity. For sheet metal formed by deep drawing, high plasticity, low yield limit, and large plate thickness directionality coefficient are required, while materials with high hardness are difficult to deep draw. The smaller the yield strength of the sheet metal, the better the stamping performance, and the greater the limit degree of one-time deformation.
- Good Surface Quality
Generally, materials with good surface quality are chosen because the parts are less prone to breakage during stamping and there is less waste. Moreover, if the quality is too poor, it can cause cracking. The good surface quality of the parts helps to improve the lifespan of the die and is less prone to scratches. So it is generally required that the surface of stamping materials should not be rough, achieve a smooth and flat effect, and also meet the problems of oxygen-free skin, rust spots, cracks, scratches, etc.
Steps for Progressive Stamping Die Design
1.Design Task Book
The design task book serves as the main basis for progressive stamping die design. Before designing the task book, designers should receive some important materials as part drawings, which mainly include the annual output of the product, product performance, manufacturing materials, and technical requirements for using the press. From the product design drawings, designers are proficient in mastering the shape, structure, dimensions, tolerance accuracy, manufacturing materials, and some related technical conditions of the workpiece.
2.Product Process Analysis
Before processing, technicians choose a suitable press and can choose the equipment based on the existing machine situation, product, and workpiece quantity. Based on the existing manufacturing level and machine conditions, provide a basis for die structure design. Analyze the dimensions, shape, accuracy requirements, cross-sectional quality, and assembly-matching relationship of the workpiece based on the provided product drawings. Due to different production batches of products, the structural form of the die and the materials used are also different. The selected materials must meet the requirements of the stamping process, and the use of strip, sheet, coil, or corner waste materials for stamping should be determined based on the process requirements.
3.Design a Reasonable Stamping Plan
Based on the analysis of the product’s process, the designer designs basic process properties, such as deep drawing, cutting, bending, and punching processes. To determine the number of processes, calculate the number of deep drawing times through process calculations. Determine process combinations based on product manufacturing quantity, product materials, equipment, and product quality. The order of process arrangement may vary, and the sequence of process arrangement is determined based on the deformation properties and size requirements of each process. If the requirements are different, the order used is to bend first and then punch, and another situation may be to punch first and then bend.
4.Process Calculation
When designing progressive die stamping, calculate the dimensions of the working parts of the convex and concave molds and determine the clearance between them. The designer calculates the size of the blank, arranges the sample correctly, and draws a layout diagram to calculate the quantity of materials used. Calculating the punching force mainly includes unloading force, forming force, drawing force, punching force, pushing force, edge holding force, and bending force, which helps to choose which type of press. Calculate and determine the external dimensions of the main components of the die, including convex dies, concave dies, convex die fixing plates, and cushion plates, as well as the size of elastic components. Determine the drawing die pressing edge ring, drawing frequency, size allocation for each process, and size calculation for semi-finished products. Select the type and process of the press that meets the requirements. Calculate the pressure center to improve the service life of the die and prevent it from being affected by eccentric loads.
5.The Overall Design of Progressive Stamping Die
The types and standards of design-oriented components. Consider whether to use guide parts and which form of guide part to use. The most commonly used guide parts in design include guide sleeve guide, guide sleeve and ball guide, sliding guide, and generally choose professional manufactured standard specifications. Stamping die structure design to ensure that the form and standards of the structural components meet the requirements. Punching, forming parts, and determining standards. Choose the structural form of the convex die, progressive stamping die design, and convex-concave die, such as combination, whole, or inlay, and what fixing method to choose.
There are two forms of unloading, such as elastic unloading and rigid unloading. Elastic unloading generally uses elastic components, such as springs, rubber or nitrogen springs, etc; Another form is rigid discharge, which usually uses a fixed discharge plate as its structural form. Choose the appropriate type and specification of the die seat. Select the positioning component. If using positioning plates or stopper plates, guide pins, etc., for progressive dies, it is also necessary to consider whether to use the starting side blade, guide pins, and stopper pins. Design the unloading and pushing mechanism properly.
Problems and Measures in the Progressive Stamping Die Design
Design reserved empty steps to assist technicians in debugging and die modification.
When designing continuous deep drawing parts or products with unstable forming dimensions, it is important to pay attention to the design of empty workstations, as the design of empty workstations plays a very important role. For these stamping dies, when designing the layout diagram, leave a few empty workstations after the first deep drawing and forming, leaving some room for adjustment. The purpose is to make appropriate changes and adjustments if necessary after the trial die. Regarding the capping parts, there is an empty workstation left between the first and second deep drawings.
In addition, if there is a situation where the distance between the punching convex or concave die holes is too close, the designer should leave space on the layout diagram to protect the needs of hard alloy inserts, concave die inserts, small die bases, convex dies, and other structures. Leave an empty workstation between the shaping step and the final feeding step to ensure the smooth progress of the production process, avoid possible changes and problems, improve product quality and production efficiency, facilitate the installation of concave dies and discharge plates, and enhance the strength of the concave dies.
With many punching holes, the length of the small punch should not be too large.
For progressive stamping die design, due to the inconsistent size of the punch, different heights of the punch can be made, forming a stepped pattern. Its advantage is that it can avoid the maximum punching pressure of each punch occurring simultaneously, effectively reduce the punching pressure of the die, and ensure that the accuracy and quality of the punching meet the specified requirements. However, it should be noted that for stepped dies, to ensure sufficient rigidity, smaller dies should be made shorter, while larger dies should be made longer. The difference in height between the two is the thickness of the sheet metal. When stamping in this way, first punch the large hole and then punch the small hole. Otherwise, it will result in the material squeezing the small punch when punching large holes, which can easily cause deformation of the workpiece or damage to the small punch. The small punch will break due to insufficient rigidity.
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