In the traditional die, ram of the press gets fastened to punch holder. We fasten die shoe to the bolster plate. After fastening punch holder to the punch, opening in the die block is aligned to the opening in die block using guide pins. Scrap strip is held by stripper so that punch may pull out of hole.
Working of the die punch
In case we use inverted dies, the position of die and punch is interchanged. The reason may be that bolster plate opening is too small for the finished part to pass through. Die block remains fastened to punch holder and punch is fastened to die shoe. Ram descends and the blank is sheared from the strip. You can get the best one available from the Die Punches Manufacturers.
Types of die punches
We use a variety of die punches. The different types of die punches include the following:
In an inverted die the punch forces its way through the scrap strip and punches on a spring attached to the stripper. This causes it to compress and load. On the upstroke, the shredder pushes blank out of die hole. Stripper forces the scrap strip off the punch.
In compound dies, we see a combination of conventional dies with inverted dies in one station. Workpiece gets pierced and blanked in one action. The piercing is loked to the punch holder in conventional position. For piercing we need the die opening. This is machined into the blanking punch. The blanking die and blanking punch are mounted in an inverted position. The blanking punch is fastened to the die shoe. The blanking die opening is fastened to the holder. .
Progressive die working
The makers of packaging for pharmaceutical medicines make use of a Tablet Press Mould. The Mould comes in many shapes and sizes depending on the tablet and amount to be packed. Next is the progressive dies. Here we see two or more operations being performed each time the ram descends. The stock strip goes through a series of stations with a series of operations being done at each step. Here we must make sure the distance between successive stations remains same. The workpiece progresses from first to the last station.
Each operation starts when previous one completes. If there are four stations, you will see four operations completed at the end of the cycle. The various operations include drawing, forming, blanking, piercing, and so on. The next is combination dies. In these types of dies, a cutting operation is combined with a non-cutting operation. The cutting operations include trimming, piercing, blanking, and so on. The non-cutting operations might include forming, bending, extruding, and so on.
The design must make sure that the can withstand the maximum piercing or blanking pressure. They must not deflect during operation. You can avoid deflection by making the diameter of the body bigger than the cutting diameter. Small punches may need support otherwise they will break. Our punch is held in position and strengthened by the punch plates. Piercing punches must remain bigger than stock thickness. Do not design punches that are more than 4 inches in length.