Diecutting Punches – Types

General

Punches come in a variety of heights – the most common being .937″ and each can be altered to meet your specific application. Punch life is effected by the material being cut, the application for which the punch was designed and operator error.
Tube

Tube punches are the most economical of all the punches and are used for the widest range of applications. Slugs cut by a tube punch do not feet thru the punch, but are left in the product being cut with help of die ejection. A standard tubular punch by definition is a piece of 16-gauge tubing that has a bevel machined on one end to specific size. Tube punch cut sizes span the decimal chart in both millimeter and inch measurements and can be machined into virtually any custom size. A quality tubular punch should have a chamfer on the bottom on the bottom on both the inside and outside to aid in ease of insertion into the dieboard. The base size should have a .000″ to .003″ tolerance, the cut edge bevel should be virtually free of tool marks and the cut edges should be razor sharp. Springs are available in tube punches to alleviate the need for die ejection. These springs should protrude approximately 1/16″ from the cutting edge. A quality tube punch will also be clean of scale, free of burs, have a case depth of .003″ to .005″ and a surface hardness of 58-60 Rockwell.
Straight Wall

Straight wall punches are used for applications with minimum punch space allotment where the base size of a standard tubular punch would be too great. Straight wall punches cause less distortion of cut size in thicker materials. The slugs cut by this punch are left in the product through the use of ejection or springs share the tubular punches tolerances and quality guidelines.
Feed-Thru

In a feed thru punch, the slug exists punch through the bottom rather than the side as the in side outlets. Feeds thru punches are used when an application calls for the scrap to be removed from the product rather than being hand stripped at a later time in the manufacturing process. Feed thru’s must run on a bolster plate which supports the die while at the same time allowing the slugs of feed thru where they are vacuumed, blown away, or otherwise disposed of. Feed thru’s are constructed from thin wall tubing which is spun or sized then re-machined to your specific cut size. This method assures the proper relief for slug ejection. Feed thru specs and sizes offered are much the same as a tube and straight wall, except that the feed thru’s inside the chamfer is minimal, the cut edges have a slight support bevel on the inside for the strength, and they do not come with springs.
Side Outlet

The slug of a side outlet punch feeds through the exhaust chute machined into the side of the punch. Side outlet punches are used when your application calls for scrap to be ejected – as in feed thru – but this punch does not require the use of a bolster plate. Other than the location of the exhaust hole for the slugs, differences between the feed thru punch and the side outlet are that the side outlet is machined out of a solid piece of steel, and it’s use of a shoulder. A side outlet shoulder is defined as the machined area of the punch from the top to the cut edge to just above the exhaust chute.

The most common type of side outlets is standard and heavy duty. The heavy-duty side outlet is used for thicker, heavier, abrasive materials, has an elongated shoulder often includes a “knurl”. A knurl is raised portion located at the bottom of the punch similar to the texture to a ratchet handle. It is approximately .005″ to .010″ larger than the base size of the punch and is 1/4″ wide. The knurl is used to prevent the punch form spinning or becoming misaligned in the dieboard. The standard side outlet is used for easier to cut, medium to thin materials. It has a shorter shoulder than does the heavy duty and does not include a knurl unless specified. A quality side outlet should be razor sharp, free of tool marks, scale and burrs. It should include a slight support bevel on the inside for strength as well as the undercut, which prevents the slug from jamming the punch before it enters the exhaust chute.
Cup

Cup punches are strong, solid steel punches that use a spherical shape to cut, compress and remove the slug. They are often used in place of a tube with spring combination and offer accurate concentricity from the cut to base. Standard cup punch sizes range from 1/32 to 31/64.
Custom

Custom punches are seamless and can be manufactured to virtually any shape or size. They are used when high tolerance, accurate cuts are required and where rule would fail. Custom punches can be used to produce everything from high tolerance flex circuits, to components used in military aircraft, to the gasket in your car.