Selection of the specifications of the punch is mainly based on these technical parameters

The selection of punch specifications After the type of punch is selected, the specifications of the equipment must also be determined. This work is determined by coordinating the size of the mold and the equipment parameters according to the process plan and the calculation results of the art during the mold design. The selection of the specifications of the stamping equipment is mainly based on the following technical parameters. (1) The impact force that the nominal pressure punch slide block can produce during the downward process is the pressure of the punch press. The pressure of the mechanical punch press varies with the downward position of the slide block (for crank punch presses, it can also be regarded as the angle of crank rotation). However, the nominal pressure refers to the maximum impact force that the slider can withstand when the slider slides to a certain distance before the bottom dead center, or the crank rotates to a certain angle before the bottom dead center. This specific distance is called the nominal pressure stroke, and the corresponding crank angle is the nominal pressure angle. The nominal pressure reflects the impact force that the punch itself can withstand. Nominal pressure is an important technical parameter for selecting punch specifications. In order to ensure the safety of punching production, the process force required for punching must be immediately lower than the allowable pressure of the punch. In the stamping process, different types of stamping processing have different changes in the punching force. At the same time, the maximum impact force of the punch slider is also changing. Therefore, it should be based on the allowable pressure curve of the punch and the actual force curve of the specific punching type. Select the nominal pressure so that the actual pressing pressure curve is completely below the allowable pressure curve of the punch. (2) Closing height and mold loading height When the punch slider is at the bottom dead center, the distance between the lower end surface and the upper surface of the worktable is called the closing height of the punch. The difference between the closing height of the punch minus the thickness of the mattress board is the height of the mold. If an inorganic mattress board is used, the closed height is equal to the height of the mold. The adjustment screw in the adjustment connecting rod can realize the adjustment of the height of the mold assembly within a certain range. When the slider is adjusted to the upper limit position, the height of the mold assembly reaches the maximum value, which is the maximum mold height; on the contrary, when the slider is adjusted to the lower limit position, the mold assembly height is the minimum mold height. The difference between the two is the amount of adjustment of the mold height. (3) Slider stroke Slider stroke refers to the distance that the slider travels from the top dead center to the bottom dead center. For crank punch presses, the slider stroke is equal to twice the crank radius. Its size reflects the working range of the punching machine, and long strokes can punch parts with higher heights. The determination of the stroke of the punch slider mainly considers the smooth placement of the stamping blanks into the mold and the smooth removal of the stamping parts. The stroke of the punch slider should be twice the height of the stamping parts. (4) The number of strokes The number of strokes refers to the number of times that the punch slider reciprocates between the upper and lower dead points per minute. The number of strokes has a greater impact on productivity, which is mainly determined according to the productivity requirements, the allowable deformation speed of the material and the feasibility of continuous operation. (5) Work table size The size of the punch work table (or backing plate plane) should be larger than the horizontal size of the lower mold, generally 50-70mm larger on each side to facilitate mold installation; at the same time, the plane size of the lower mold must also be larger than the work table The size of the face generally needs to be 45-50mm larger on each side, and the size of the worktable hole must be larger than the size of the possible missing material. (6) Die shank hole size There is a die shank hole at the center of the lower end of the small and medium-sized punch slide block to facilitate the installation of the upper die. The diameter of the die handle of the die should be the same as the diameter of the punch die shank hole, and the length of the clamping part of the die handle should be slightly less than the depth of the punch die shank hole. When selecting stamping equipment, the actual conditions of the cattle production site should also be considered. If there is no more ideal equipment to choose from, you should try to use existing equipment to realize stamping production; if there is more than one equipment that meets the requirements, you should comprehensively consider the production requirements of other products and the rational use of equipment resources. Previous post: How to simply press the guide post into the guide sleeve during the assembling of the mold base