Metal stamping continuous dies can be used to establish low-cost and high-efficiency automated stamping production lines. Since continuous dies require precision and complex components, the issues that need to be paid attention to during design are more sophisticated than those for general stamping dies.

1. When punching more holes, the length of the small punch should not be too large. For multi-punch stamping dies, punches of different heights can be made according to the size of the punches to form a stepped type. It can avoid the maximum punching pressure of each punch being generated at the same time, which can effectively reduce the punching pressure of the mold and reduce the load of the punching machine. However, it should be noted that for stepped punches, in order to ensure that the punches have sufficient rigidity, the small punches should be made shorter and the large ones longer, with a height difference of the sheet thickness). In this way, the large holes are punched first and the small holes are punched later. Otherwise, when punching the large hole, the material will squeeze the small punch, and the small punch will break due to insufficient rigidity.

2. Try to add stoppers, side blades and other step positioning devices to the continuous die.

When punching workpieces with a continuous die, the problem of accurate positioning of the strip must be solved to ensure that the step of the continuous die is consistent, so that qualified parts can be punched out. In the continuous die, the commonly used positioning devices include fixed stopper pins, guide pins, guide plates, side blades and other forms. When punching, use the fixed stopper pins for preliminary positioning, and use the guide pins installed in the die to ensure the correct positioning of the strip when blanking. The side blade is used to control the distance of each step of the strip feeding. The length of the side blade should be equal to the step length plus 0.05-0.5mm, depending on the thickness of the material.

3. The guide pin (guide needle) of the continuous die should not be too long

In order to control the feeding step, the continuous die must have a better positioning device. Common positioning devices include guide pins, initial stop pins, side blades, guide pins, etc. Among them, the guide pin is a widely used precision positioning method in the continuous die. It can also alarm and stop the machine when used with the misfeed detection sensor to protect the mold. Therefore, it is often used in continuous stamping dies. In high-precision continuous stamping dies, pre-punching is often used, and then the guide pin is used to guide the coil in each step. At this time, the diameter of the guide pin used is usually ∮1.2~6mm. It must be noted that the length of the guide pin cannot be too large, and the length entering the guide hole cannot be too large, otherwise it will cause poor feeding of the mold, carrying of materials, etc. For this reason, the straight length of the guide pin of the continuous stamping die should be: the thickness of the guide pin fixed template + 1 material thickness.

4. It is not suitable to use PU or polyurethane rubber as unloading components in automatic punching dies such as continuous dies

For high-efficiency production dies such as continuous dies, their lifespan is often more than 500,000 to 5 million strokes, and the punching speed is more than 40 times/min. If elastic components such as PU and polyurethane are used for unloading, on the one hand, the unloading force may be insufficient and the unloading may be unreliable. On the other hand, their lifespan is also limited. In order to ensure the reliable and normal operation of the continuous die and reduce maintenance, springs with long lifespan should generally be used as unloading components.

5. Complex or slender shapes in continuous stamping dies should not be punched out at one time: Complex and slender shapes in continuous dies should not be punched out at one time. If the process allows, they should be split into several punches and stamped in steps. This will make the die hole easier to process and extend its service life, and facilitate die repair and improve production efficiency.

6. Design reserved empty steps to facilitate debugging and mold modification: When designing continuous deep drawing parts or products with unstable forming dimensions, the design of empty stations cannot be ignored. For such molds, when designing the layout diagram, one or two empty stations are often left after the first deep drawing and forming, leaving some room so that appropriate changes and adjustments can be made after the mold trial. For the cover parts, there are empty stations between the first deep drawing and the second deep drawing. In addition, when the distance between the punch or die openings is too close, in order to protect the punch, die insert, small die frame, carbide insert and other structures, empty stations should also be left on the layout diagram. Leaving an empty station between the shaping step and the final blanking step is convenient for the installation of the die and the stripper plate, and improves the strength of the die.

7. Anti-chip jumping design: The continuous die is a process of continuous stamping of a product, especially when there are many punching holes and cutting edges. In order to avoid product crushing and the stability of the die during the stamping process, an anti-chip jumping structure is usually required. The following points are mainly considered: 1. The punch is made into a special shape to increase the adhesion of the waste on the blade; 2. The punch is equipped with a blowing hole; 3. The blade is made into a V-shaped or dovetail clamping form; 4. Reasonable blanking and cutting gaps are placed to reduce chip jumping; 5. In-mold waste suction device.

8. The carrier of the continuous die cannot be deformed: the workpieces of each process in the continuous die are transferred by the overlapped surplus material of the strip, and the workpiece is generally separated from the strip in the final blanking process. This overlap is called the carrier of the continuous die. Since the continuous die has high requirements for step accuracy, in order to ensure the dimensional accuracy of the step and improve the stability of the continuous die, the carrier cannot be deformed. Therefore, the design of the carrier is an important aspect of the continuous die design. In order to ensure that the carrier has sufficient strength and rigidity, it is often adopted to appropriately increase the overlap size; when the strength of a single-sided carrier is insufficient, a double-sided carrier and an intermediate carrier can be designed; a process cut is punched out between the carrier and the workpiece to separate the carrier and the workpiece, and the deformation of the workpiece will not affect the deformation of the carrier.

9. Quick disassembly and parts foolproofing: In the design of continuous molds, quick disassembly of parts and foolproofing of parts/standard parts are particularly important. Because the purpose of rapid mold repair is to achieve, the entire mold is rarely removed from the machine during continuous mold repair. Instead, the parts and templates that need to be repaired are removed separately when the machine is shut down, so a quick disassembly structure needs to be designed. When removing parts and templates and replacing them with new parts, it is often easy to misinstall parts and get the template direction wrong, resulting in damage to the mold, so it is necessary to pay attention to the foolproofing of parts and templates.