Process method for hole punching of multi-station progressive die

Abstract

The invention discloses a process method for hole punching of a multi-station progressive die. The multi-station progressive die comprises puncher pins, a material pressing device and the lower die plate, the lower die plate is provided with a concave die and is not provided with a concave die corresponding to the puncher pins and the material pressing device respectively, and when processing materials carries out progressive operations along the lower die plate in the multi-station progressive die, the process method comprises the steps that 1, the first puncher pin punches the processing materials with a thickness t, the depth s of the puncher pin enables the processing materials to form an upper concave portion and a lower convex portion, and the puncher pin withdraws; 2, the convex portion is pressed back to the processing materials through the material pressing device and the lower die plate; 3, the second puncher pin punches the concave position of the processing materials in the first step again, and the convex portion is punched, and a small hole is formed. The process method has the advantages that punching is carried out on the small hole twice or more times, the maximum length enabling a convex die to be bent and to be steady is increased, the hole size limit of conventional hole punching is indirectly reduced, that is, a convex die with a small section can be adopted when holes with identical sizes are punched, and breakage does not easily occur.

Description

Technical field [0001] The invention belongs to a die punching method, and specifically relates to a process method for punching small holes in a multi-station progressive die. Background technique [0002] Punching small holes in cold stamping dies refers to punching where the hole diameter is smaller or close to the thickness of the material. In engineering, the types of small holes are like figure 1 Shown are (a), (b), (c), (d) four. When punching small holes, the punch is very easy to break. After analysis, the failure trend of the punch for punching small holes belongs to the instability of the pressure rod. In order to obtain the normal service life of the punching mold, protective measures are not taken according to the compressive stress check. The hole size limit for conventional punching is shown in Table 1. That is, as long as the size of the small hole in the product is smaller than the size listed in the table, it cannot be obtained directly by the punching method. ...

AI Technical Summary

Problems solved by technology

[0005] In order to meet the needs of processing small holes smaller than the limit listed in Table 1, two methods are usually used in engineering at present: first, the structure of adding a protective cover to the punch, such as figure 2 As shown, the structure of adding a protective cover 2 to the punch 1, due to the increase of the cross-sectional moment of inertia of the punch, the small punch almost loses the possibility of instability, deformation or even breaking, so that the same length of the punch can be obtained as compared to Table 1. Smaller-sized punching holes, however, the small hole size obtained by this method is still limited, because the reduction in punching diameter is ultimately limited by the limit of the compressive strength of the punch material

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