The Process of extruding aluminum shapes at Iowa Aluminum is considered an art, because so many factors go into making an aluminum shape from start to finish.  Getting a quality part to our customer means satisfying all the factors that are present in the aluminum extrusion process.  The following is a general idea of how the process works to include the design, tooling and the extrusion process from beginning to end. 

Dies and Tooling

The aluminum extrusion process seems quite simple; however, there are many factors that must take place before an extruded shape can be made.  The first step is the design factor.  The design of an aluminum shape depends on the final intended use of the shape.  There are many factors that affect the design of the shape such as machining capability, finish and environmental use, which all play a role in determining the choice of alloy to be extruded.  The function of the profile will determine the design of its form and the design of the die that will shape the extruded part.

Once all of the factors of the design have been determined, the next step of the extrusion process is the tooling that is needed to extrude the shape. The design of the tooling depends on the design of the shape itself.   The shape is a determining factor in the cost of the part and the ease of extruding.  In the extrusion process there is a wide variety of shapes that can be extruded, but limiting factors must be considered prior to making an extrusion die. These factors include size, shape, alloy, extrusion ratio, tongue ratio, tolerance, finish, factor, and scrap ratio.  If the shape is beyond the limits of these factors, it will be very difficult to extrude the shape successfully.

Extrusion dies can be made to accommodate many shapes and sizes that meet the criteria necessary to extrude successfully.  Since Iowa Aluminum has direct access to its own Die Shop, the initial costs and lead-time of aluminum extrusion dies and supporting tools are usually a good deal lower than the tooling produced by extruders that must rely on independent toolmakers to make their dies.  There are, however, several factors that influence the actual cost and lead-time of a specific die and that is cooperation from the product designer, the die maker, the extruder and the purchaser in recognizing each other’s requirements and working together to maximize product performance and quality while minimizing the overall cost.

When all of the factors have been satisfied and the tooling has been produced, a normal die assembly would include a “Tool Stack” consisting of the die itself, a backer enclosed within a die ring that is placed in front of a bolster and a sub bolster that supports the die during the extrusion process.   A typical “Tool Stack” for a solid  die is shown below.

Direction of Flow for a Solid Die

SOLID DIE

This is a picture of a typical solid die with four cavities that allow a flow of four identical shapes to be extruded at once.

Extrusion Process (continued)

Iowa Aluminum, Inc.  ~  10-27th Ave. East  ~  PO Box 306  ~  Albia, IA 52531

Phone:   641.932.7410  ~   Fax:  641.932.5381