3.2 Shearing

※  THE TYPEOF BLANKING DIES

Simple Die

The die that only one process is carried out in one press stroke iscalled simple die (Fig.3-7). Its structure is simple, so it can be easilymanufactured. It is applicable to small batch production.

1-Punchholder; 2-Spring plug for stripper bolt (or coil spring); 3-Stripper bolt;4-Cap screw; 5-Shank; 6-Stop pin; 7-Pin (or dowel pin); 8-Backing plate;9-Punch plate; 10-Punch; 11-Stripper plate; 12-Die; 13-Ejector; 14-Die holder;15-Eject pin; 16-Plate; 17-Bolt; 18-locating pin; 19-Guide post; 20-Guide bush;21-nut; 22-rubber

FIGURE 3-7 Simple blanking die

※ Compound Die

The die that several processes are carried out at the same dieoperation in one press stroke is called compound die. The main characteristicof the compound die is that the certain part is both the punch and the die. Theoutside circle of the punch-die is the cutting edge of the blanking punch, whilethe inside hole is a punching die.

Compound dies are highly efficient tools. For example, compound diescan perform operations on both sides and the perimeter of a cardsimultaneously, while also creating the desired hole or perforations. Theupfront costs of compound dies are higher, typically 125 to 130 percent that ofa progressive die. But especially in more complicated applications, thecompound die is the only method of creating a card with the desired quality.The key advantage of compound dies is their unsurpassed mechanical accuracythat derives from all operations occurring with one press stroke.

※ ProgressiveDie

The die that several blanking proesses are carried out at differentpositions of the die in one press stroke is called progressive die, as shown inFig.3-9. In the operation, the locating pin aims at the locating holes punchedpreviously, and the punch moves downwards to punch by one punch and to blank byanother punch, thus the workpiece is produced. When the punch returns, thestripper scrapes the blank from the punch, the blank moves forward one step andthen the second blanking begins. Above steps are repeated continually. The stepdistance of the blank is controlled by a stop pin.cardsimultaneously, while also creating the desired hole or perforations. Theupfront costs of compound dies are higher, typically 125 to 130 percent that ofa progressive die. But especially in more complicated applications, thecompound die is the only method of creating a card with the desired quality.The key advantage of compound dies is their unsurpassed mechanical accuracythat derives from all operations occurring with one press stroke.

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