Rheocast Meets the Challenge to Produce a Complex Brass Counterweight

Problem: An original equipment manufacturer wanted to switch from using zinc to brass for production of die cast counterweights used in high-efficiency compressor motors for air conditioning systems. Brass, being heavier than zinc, allows more weight to be contained within a smaller package, which is beneficial for motor design. However, the counterweight carries stringent requirements for both weight and density to achieve the desired motor balance. These criteria are not only an unusual requirement, but especially challenging when die casting brass components.

Solution: The potential customer contacted Rheocast with their design objectives. We constructed a single-cavity prototype tool in support of their research and development into determining the final counterweight parameters. Process management strategies were created to meet the targeted high-density specification, as well as the weight criteria controlled to within ±2.5 grams. Production-grade tools were designed and built using a single mold with multiple, interchangeable cavities to produce a total of 18 part numbers with a range of weight specifications from 210 grams to 375 grams. The product line is now in full production.

Conclusion: Our customer is very pleased with the performance of the final product design, both in the field and its rapid growth in the marketplace. Rheocast is proud to have contributed successfully engineered solutions to realize this complex die casting component.