Deep drawing services form parts by using a punch to radially draw a sheet metal blank into a forming die. The part is re-drawn through a series of successively smaller dies until its depth is greater than its diameter. Unlike stamping, a metal forming process that transports materials along a carrier, deep drawing does not require strip-fed operation. Drawn parts can be made from aluminum, brass, copper, and steel, and feature a seamless design. Typically, the deep drawing press pushes single blanks through multiple positions.
Selecting deep drawing services requires an analysis of supplier capabilities and the industries and/or applications served. Many suppliers also offer additional or secondary services such as anodizing, machining, heat treating, stress relieving, soldering, welding, and threading.
Types of Deeping Drawing Techniques
Deep drawing can be achieved with tools, an active medium, or active energy. The first two methods are the most common.
- Rigid tools are typically used for deep drawing and generally include a die, a punch, and a blankholder. The punch and the die are used for forming and the blankholder is used to regulate the material flow. This is important to guarantee deep drawing without crinkles and cracks.
- Active medium deep drawing may involve force transmission action, typically with a gas or liquid.
- Active energy deep drawing, also known as high speed forming, is an alternative method of deep drawing that has little practical use over other conventional methods.
Other unconventional deep drawing is used to extend the formability limits associated with more conventional metal forming methods. Examples of these unconventional drawing techniques include hydraulic and hydromechanical deep drawing, as well as the hydroform, aquadraw, Guerin, and Marform processes.
Marform Deep Drawing
The Marform method uses rubber-pad forming to produce deep-recessed parts with either sloped or vertical walls. The die apparatus uses a rubber pad that is typically 1.5 to 2 times the thickness of the part to be formed. The dies themselves are usually made of lightweight alloys.
In Marforming, as this process is commonly known, a blankholder is used to hold the metal blank against the rubber pad. Although the punch acts in a similar fashion as in conventional deep drawing, this method produces parts without wrinkles.
Deep Drawing Applications
As an alternative to metal stamping, deep drawing is used to produce automotive body and structural parts as well as aerospace and aircraft components. Consumer products and complex industrial components can be made on a press line or with progressively-smaller dies in a single press. Examples of deep drawn products also include metal eyelets and enclosures.