10.1 INTRODUCTION

Punch plates hold and support piercing, notching, and cut-off punches. They are usually made of machine steel, but can also be made of tool steel that has been left soft for high grade dies. Punch plates range from small simple blocks for holding single piercing punches to large, precision- machined plates for holding hundreds of perforators. Important design considerations include:

1. Adequate thickness for proper punch support.

2. Good doweling practice to insure accurate location.

3. Sufficient screws to overcome stripping load.

Numerous methods of designing punch plates and applying them to various types of dies are described in the remainder of this chapter. These methods further explain Step 5 in Chapter 5 Fourteen Steps to Design a Die.

10.2 METHODS OF DESIGNING AND APPLYING PUNCH PLATES

10.2.1 Design Conception

a Punch Plates for Single Punches

A punch plate for holding a single punch (Figure 10.1) is made square and with sufficient thickness for good punch support. Two socket cap screws, applied at the corners, resist stripping pressure, while dowels at the other two corners provide accurate location. Minimum distance from plate edges to screw centers A is 1 1/2 times screw diameter B.

Figure 10.1: Punch plate for a single punch.

Stripping force. When center distances are small, a single punch plate can hold a number of piercing punches. When a large number of punches are retained, the stripping force should be calculated to insure that sufficient screws are used to fasten the punch plate to the die...