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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. |
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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,
which together with a backer, is
enclosed within a die ring that is placed in front of a bolster
with a sub bolster behind, all held together as a unit by a tool
carrier. The backer, bolster, and sub-bolster provide the
necessary support for the die during the extrusion process.
A typical "Tool Stack" for a solid die is shown below. |
