High Pressure Die-Cast Aluminum Brake Arm Study 2002-01-2131

High Pressure die-casting is a common aluminum casting process used to produce many automotive and electrical parts. In this development process, the goal was to produce a die cast aluminum brake arm for Teleflex's patented adjustable pedal design.

In late 2000, Teleflex Automotive began a joint development program with a die cast supplier for an adjustable pedal brake arm conversion from steel to die cast aluminum. Die Casting was selected due to its low cost of manufacture in volume applications and flexibility in design.

Summary of Benefits over current steel pedal arm:

• Weight savings
• Elimination of MIG Welding
  • Improved reliability
  • Reduced complexity
• Replace 3 parts with one part
  ○ Reduced complexity
• Improved dimensional tolerances
• Reduced Process Failure modes

After the initial CAD model was completed, Finite Element Analysis (FEA) was performed. During the course of the design development, several prototype parts were constructed and tested.

A final prototype run was made in a standard production machine under normal operating conditions. To test the robustness of the process itself, a DOE was conducted where in some of the key process controls were deliberately altered well beyond the normal control limits.

The parts were then tested according to a test plan. Statistical analysis was performed on the nature of the relationship of porosity and strength and other interrelationships.

From the results of these analyses, it was possible to establish criteria for acceptable levels of porosity within the part.

Further in vehicle tests are to be performed to evaluate the part made of this material for this application. The design process involved many steps in the finite element analysis, DOE, casting and statistical evaluation methods. This paper covers the essentials in each of the areas since the details of each step are too many to list here.