Environmentally conscious re-design of turbine blade fixtures

摘要

This paper examines the re-design of turbine blade fixtures for the plasma spray coating process. The plasma spray process is used to apply a ceramic coating to turbine blades prior to gas turbine engine assembly. Without the ceramic coating, the blades would fail under the high temperatures produced during combustion. As a result, the plasma spray process is essential to modern gas turbine engines; the process as is stands, however, is environmentally expensive. Turbine blade holding fixtures are an integral part of the coating process, to both hold the bladesd within the furnace, and to protect precision assembly feautres on the root section of the turbine blade. In addition to the fuel costs and safety problems associated with the high temperature furnace, an environmentally hazardous acid bath is used to strip the ceramic coating from the fixtures to allow reuse. This acid bath is costly in terms of both production and the environment. The fixture redesign examines the functionality of the existing fixture design using a combination of classical, design for manufacturing, and axiomatic design methodologies, and develops a new design to eliminate the need for the acid bath. The new design also improves the productivity and safety of the plasma spray coating process. A prototype for the new design has been constructed and tested. The paper also discusses the economic benefits of the improved fixture design.