Hydroforming / Hydroform is a manufacturing process where fluid pressure is applied to a ductile metallic blank to form a desired component shape. This process requires hydroforming tools consisting of a punch made in the shape of the desired part, a ring contoured to fit around the punch, and a pressurized forming chamber sealed by a flexible rubber diaphragm.

The typical process cycle starts by placing the metal blank onto a ring that is located over the lower tool (punch). The chamber is then closed over the blank and fluid pressure is applied to the top side of the sheet metal blank. At the same time the punch is pushed up into the blank. The pressure is sufficient to cause the blank to form and take the shape of the punch.

The terms Hydroforming / Hydroform and Deep Draw or Deep Drawing are many times used interchangeably, with Hydroforming now being the industry "buzz word" for metal forming. Both processes offer their own unique advantages to metal forming .The following are some design considerations (criteria) that are taken into account when determining the process to be used for a specific part.

Deep Drawing & Hydroforming Considerations

• Common shapes for Hydroformed / Hydroforming parts are domes and concave/convex/dished surfaces, whereas Deep Drawn shapes are more commonly cans, boxes, and bottles, as well as irregular shaped products.
• Hydroforming can attain up to 60% reduction on a metal blank, where Deep Drawing only a 43% reduction. However, multiple draws are not possible on a hydroformed part, whereas numerous re-draws can be performed on a deep drawn part to attain a desired depth.
• Tooling for a Hydroformed part is typically less expensive than for a Deep Drawn part, since only a punch and ring are required. Deep Drawing requires a punch, die, and blank holder. If the part is conducive to hydroforming and relatively small quantities are desired, hydroforming provides a cost effective solution to forming the part.