Metal Presswork, Stamping and Deep Drawing Expertise

Deep drawing explained

The process of deep drawing a component begins with the sheet metal, in the form of coil strip or lengths, being fed into the press either automatically or manually. Part of the press tool called a die, is used to cut a piece out of the material into the required outline. This outline is called a blank, which is then formed into the deep drawn component shape following a series of stages.

When the punch of the drawing tool forces a portion of the blank through the bore of the die, different forces come into action to cause a somewhat complicated flow of the material. The material is bent and wrapped around the punch nose, whilst the outer portion of the blank simultaneously moves radially towards the centre of the blank.

The volume elements decrease in circumferential length and correspondingly increase in radial length until they reach the bore of the draw ring. After becoming part of the shell wall, the elements are straight.

This results in the formation of a deep drawn cup shaped component. The volume and the thickness of the metal remain essentially constant throughout the process, with the final shape of the cup being consistent with the contour of the drawing punch.

In general the metal flow during the cupping process is as follows:

• Little or no metal deformation takes place in the blank area which forms the bottom of the cup.
• The metal flow taking place during the forming of the cup wall uniformly increases with the cup height.
• The metal flow of the volume elements at the periphery of the blank is extensive and involves an increase in metal thickness caused by circumferential compression. This increases the wall thickness at the open end of the cup wall. This increase is usually slight because it is restricted by the clearance between the punch and die.

Deep drawing to size

If the desired size cannot be achieved after the first reduction, the component can be taken through a number of further reduction stages to achieve the size required.

Most types of material can be deep drawn from a flat blank into a cup. However, due to the level of stress which the material is subjected to during this process, some types of material which are less malleable, may require an annealing operation before being taken through any further reductions after the initial stages.

Deep drawn metal applications

Typical end uses for deep drawn metal pressings include a variety of canisters, caps and casings for a wide range of applications. The automotive, food processing and medical industries are just some of the sectors which have requirements for metal components that have been deep drawn.

Deep drawing calls for highly skilled workmanship

The process of deep drawing a metal component is a highly specialised skill within the presswork field, which not all pressing manufacturers can provide.

HT Brigham is proud to include deep drawing within its presswork services, and uses this know-how to assist our customers throughout the manufacturing process – right from the initial design stages, so that we can advise on the size of the radius and shell heights which can be achieved.

Our abilities in this field enable us to competitively supply deep drawn metal pressings on a global scale into a wide range of product sectors.