How does Deep drawing work

It has long been well-known that pressing or stamping is an economical method for manufacturing metal parts. Although there's a relatively high initial cost to build tooling, deep drawn stamping is usually cheaper and always faster than alternative processes such as machining, fabrication and injection molding. Why is deep drawing often the preferred method of metal forming especially when the depth of item matches or exceeds its radius? Deep drawing takes this a further step in that it is possible to produce metal parts that are longer or deeper than can be achieved through conventional stamping processes.

What Is Deep Drawing?

Deep drawing is a form of metal stamping where a sheet metal blank is progressively formed into a three dimensional shape by the mechanical action of a punch drawing the material into a forming die. In practice, it is possible to produce cylindrical, square, rectangular or irregular shape, with straight or tapered sides or a combination of straight, tapered and curved sides.This process is considered more efficient than machining because there is significantly less wastage of metal.

The Deep Drawn Process

Deep drawing is performed in several stages, It all begins with the ubiquitous metal blank. During the first stage, the blank will be forced into a cup shape with a larger diameter than the final part diameter. During following stages, the part diameter is gradually reduced as its depth increased.

The design and construction of deep drawn tooling is crucial. Tooling is usually ganged together with some form of part transfer so that all operations take place on one press.Using these techniques it is possible to use deep drawn methodology to produce a part that's more than ten times longer than its outside diameter.

Special care needs to be taken to ensure that excessive stretching does not take place, and for this reason the initial die and punch radii need to be carefully calculated. If the die radius is too small, material will not flow properly, and if it's too great, wrinkling will occur. All tooling should be highly polished to aid material flow and high-strength tool steel used for the radius at the die entrance.

The clearance between the cup and tool is also critical to ensure the correct final ratios between stretch, flow and work hardening. The press speed is important, because if it's too high, corner cracking will occur, but if too low, material flow will be affected.

To learn more about deep draw forming, send us a message or Call Zechin Industries today at +86 158 5810 2851! Steven