Deep drawing is one of the most popular metal forming methods available to manufacturers– it involves the use of metal dies to form blank sheets of metal into a desired shape. Specifically, if the depth of the item created is equal to or greater than its radius, then the metal forming process can be called deep drawing.
The deep draw process begins with metal blanks. Typically, single blanks are used in order to facilitate the creation of parts or products with deeper shapes. Sometimes, these metal blanks will be placed on a reel to enable the metal to form efficiently. At each step in the deep drawing process, the metal blank is shaped through pressure applied by a metal die.
Though deep drawing is similar to metal stamping, the terms are not interchangeable. Stamping does not leave a single machine until the metal has completely formed. In general, deep drawing is used to fabricate parts and products that are deeper than metal stamping can accommodate.
The formability limitations of conventional deep drawing are a barrier for some industrial uses. Radial drawing stress and tangential compressive stress are a common concern that can result in wrinkling, fracturing or cracking in some applications. Numerous unconventional deep drawing techniques have recently been implemented that have helped increase the industrial uses of deep drawing. These processes include hydroforming, hydro-mechanical deep drawing, aquadrawing, hydraulic deep drawing, the Guerin process and the Marform process.
Virtually all manufacturing industries have the potential to benefit from deep drawing manufacturing processes. The technique is perhaps most useful for manufacturing small component parts such as electronics relays, solenoids, and assembly housings. Products of all shapes and sizes, however, can be economically created through the process, including items such as aluminum cans, cookware, and kitchen sinks.
Benefits of Deep Drawing
Deep drawing is especially beneficial when producing high volumes, since unit cost decreases considerably as unit count increases: once the tooling and dies have been created, the process can continue with very little downtime or upkeep. Tool construction costs are lower in comparison to similar manufacturing processes, such as progressive die stamping, even in smaller volumes; in these situations deep drawing may also prove the most cost-effective manufacturing solution.
When considering the functionality of the end product, deep drawing poses still more advantages. Specifically, the technique is ideal for products that require significant strength and minimal weight. The process is also recommended for product geometries that are unachievable through other manufacturing techniques.
Deep drawing is perhaps most useful for creating cylindrical objects: a circular metal blank can easily be drawn down into a 3D circular object with a single draw ratio, minimizing both production time and cost. Production of aluminum cans is one example of a popular use of this method.
Squares, rectangles and more complex geometries may create slight complications, but are still easily and efficiently created through the deep drawing process. Typically, as complexity of the geometry increases, the number of draw ratios and production costs will increase.
Deep drawing may be a viable production solution for any manufacturing process that requires one or more of the following:
- Seamless parts: deep drawn parts are created from a single sheet of metal
- Rapid cycle times: large quantities of products are easily manufactured through deep drawing
- Complex axi-symmetric geometries: deep drawing delivers exceptional detailing and accuracy
- Reduced technical labor: precision deep drawing can deliver similar results as technical labor in quicker time frames
Other Factors That Affect Cost-Effectiveness of Deep Drawing
Manufacturing costs increase, the subsequent appeal of deep drawing diminishes. More complex products will obviously increase maintenance costs, labor costs, and production costs. When considering the costs of deep drawing, the following factors will likely increase expected cost:
- Number of part features
- Location of part features
- Direction of part features
- Protruding part features
- Part size
- Material thickness
Deep drawing applications also benefit from the wide amount of metals that can efficiently be subjected to the process. The following metals are currently used to manufacture products through deep drawing:
- Cold rolled steel
- Stainless steel