Large Thrust Washer, Metal to Plastic Conversion

Project Details

Application: Transmission torque converter


Customer: Fortune 500 off-highway equipment manufacturer



Mold flow and precise tooling are essential considerations when injection molding such a large part.

The Objective

Convert a metal (bronze) thrust washer used in a transmission torque converter to a high-performance plastic. The incumbent part was a heavy and expensive bronze thrust washer that was impregnated through several chemical processes for increased wear resistance.  The customer’s primary goal of the conversion from metal to plastic was for weight reduction and cost savings. Secondarily, the customer wanted to address unpredictable wear in failure mode and eliminate toxic liquids used in the manufacture of the bronze thrust washer.

The Challenge

When Allegheny Performance Plastics accepted this challenge more than 15 years ago, a metal-to-plastic conversion, such as this, was a novel concept. High performance plastics were not considered for use in dynamic (mechanical and wear) applications.

The challenge the Allegheny Performance Plastics team faced were two-fold: (i) material selection and (ii) the large size of the part.

The Allegheny Performance Plastics team worked closely with the customer and material suppliers to select the appropriate resin and part design that would withstand the friction and wear demands of the application. Allegheny Performance Plastics also provided machined prototypes for testing varying designs and materials. Design of the part was critical to ensure uniform wear and moldability.

The bronze thrust washer was a very large part. When injection molding such a large part, mold flow is critical. Allegheny Performance Plastics’ success required highly precise tooling and talented injection molding process engineers.

The Solution

The result was a very successful product development that is still in production today — without a single part failure in more than 10 years.

The team at Allegheny Performance Plastics achieved all the primary goals in a significant way:

  • Cost was reduced by 50%
  • Weight was reduced by 66%
  • Part failure was reduced to 0%

In addition to meeting the primary goals of cost and weight reduction, Allegheny Performance Plastics was also able to meet the customers’ secondary objectives. The high-performance plastic thrust washer resulted in a product with improved performance as the plastic part has a consistent wear rate and pattern and by switching to a high-performance plastic the customer was able to eliminate the use of toxic liquids used in the manufacturing process of the bronze thrust washer.