#110 Terminology and Surroundings (4) Bridge and Carrier
Blanking operation is a typical one among press forming operations. In such a forming operation, a frame is created around the blank as is shown in Fig. 1. The part of this frame in the width direction of the material is called the "edge bridge" and the part in the direction of feeding is called the "feed bridge". These are necessary for forming the contour shape of the blank in blanking. Since these bridges become scrap, making them large wastes the material. Therefore, they are made as small as possible. The limit would be the smallest dimensions that cause no abnormalities in blanking.
Fig. 2 shows the progressive blanking operation. In progressive blanking, the blanking is done successively while moving the material which is kept connected by the bridge part. The "bridge" in this case is not important for the blanking operation but is mainly intended to hold the blank in a stable manner, and to feed the blank to the next process. Therefore, in order to distinguish this from the blanking bridges, most often such "bridges" are called "carriers" in progressive blanking. The three types of carriers shown in Fig. 2 are the double side carrier, the single side carrier, and the center carrier. The double side carrier holds the blank in a stable manner. Depending on the method of using, the instability remains in the cases of the single side carrier and the center carrier.
Although in general the part of the material that connects the blanks is called a "bridge", depending on the application, if the method of using is mistaken, there will be abnormalities in the product quality. Do not make simple judgments merely based on the way it is called.


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