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#141 Design of Hole Punching Dies (1) Structure of Hole Punching Dies

Category : Shear Forming
January18, 2013

Hole punching dies can be said to be the dies that are used most frequently next only to blanking dies.

Fig. 1 shows a hole punching die having a fixed stripper structure. Since the structure of the die is simple, preparing the die is easy.
Since a die of this structure does not keep the work pressed, the flatness tends to become poor in the periphery of the hole. This type of die is used frequently when wanting to punch a hole at the end of a long shape.
In the example shown in the figure, although the guiding along the width direction of the work material is being done by a pin, it is also possible to use a plate.
The work material is processed while pushing it towards the deep end of the fixed stripper.


Fig. 2 shows a hole punching die with a movable stripper structure. This can be said to be the standard of a hole punching structure.
The work material is pressed by the movable stripper thereby aiming to prevent deformations such as warping, etc.
Since the work material is pressed between the die plate and the stripper plate, there is the drawback that it is easy for scratches such as dent marks to be made on the product.


Fig. 3 shows the structure used when there are holes to be machined at the two ends of a large product.
When the entire unit is made from one plate, there will be a lot of waste and the weight will also be more. In addition, when a single process machining is assumed, there will be a feeling of pressure and the ease of press operation may be decreased. This is a structure in which only the necessary parts are prepared and placed which simplifies the die.
In the case of long products, if there are forming units at both ends, the middle part may sag. In such situations, it is stabilized by providing support at suitable parts.


The above are hole punching dies assuming that the work is a flat plate. It is also possible to punch holes on the sides of a drawn product, or to punch holes in a bent product.
The operation is done by making suitable alternations in the placement of the product, or else, it is also possible to punch holes from the side using cams.

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