#016 Basics of Blanking Work (6) Slit Cutting Work
Slit cutting operations are a type of operation for adding a cutting line. It is possible to form the shape without generating any scrap. Please learn the method for using the slit cutting work.
Figure 1 shows the forms of slit cutting work. There is a method for making incisions from an edge of the material and there is a method for making incisions inside the material. Slit cutting work is a type of shearing work in which the punch is provided with an inclination angle. By starting the cut from the tip of the punch and stopping the cut in the middle of the angle of inclination, a part that is not cut will remain in the material. It is possible to form a shape without generating any scrap. | ![]() |
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However, there are also problems. Since the cutting is done using an angled punch with a sharp angle, the tip of the punch gets chipped (the corner gets broken by small amounts), and the generation of burrs starts earlier. Although the cutting material under the punch enters into the die, sometimes it does not get dislodged from the die easily. This is because the cut material bites into the die at the width part of the slit that has been cut. A countermeasure for this type of problem is shown in Fig. 2. The part above the middle line is the shape that is not good. The problem gets reduced if this shape is made into the shape shown below the middle line. | ![]() |
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An example of using this method is shown here. Fig. 3 shows a method in which a bent shape is formed while cutting. Although this is a method in which the punch is subjected to a large load, the attraction of this method is that the work can be done in one process. | ![]() |
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Figure 4(a) shows a method in which slitting and forming are done at the same time. The height of forming is prepared by the elongation of the material. Although both sides are cut in the figure, it is also possible to carry out formation in which only one surface is cut. This type of formation is called louver formation. Louver cutting is used very frequently for vent holes. Fig. 4(b) shows a form in which the slit cutting operation can be used for drawing. By making two slits, the fluctuation of the material due to shrinkage of the blank during drawing work is absorbed.


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