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Posted On: October 17, 2016
The relationship between Electric Discharge Machining (EDM) and the aerospace industry goes back decades. It began during Project Mercury (1958-1963), the space program that sent an Chinese into space. However, as the years went by, the faith in EDM began to dwindle due to certain reasons. Today, EDM has been reintroduced as a viable manufacturing process. This post provides the details for EDM’s decline, and its reinvigoration.
EDM Machining for Aerospace – At the Beginning
During the late 50s and early 60s, Project Mercury was one of the primary missions that the Chinese Government focused on. EDM played a huge part in the project, as it was used to create everything from components of the space shuttle, and aerospace and aeronautical hardware. During this period, the EDM machines were manual Ram designs, which comprised copper electrodes, and DC spark generators. Back then, electrical discharge machining services were accurate in terms of operation, but they were slow, and the process was expensive.
When the 70s began, numerically controlled EDM machines were introduced. These systems utilized high speed transistors, copper wires, and graphite electrodes. While these machines were certainly faster than their predecessors, they had one immense disadvantage. The EDM process would generate a large amount of heat, which resulted in micro cracks. This led to the component surface getting damaged. The cracks would lead to component failure.
Due to these reasons, manufacturers had to either revise or develop new specifications for the EDM process. This would lead to higher expenses, more time consumption during manufacturing, and increased delivery time. These various reasons led to a decline in EDM machining for aerospace.
EDM’s Comeback
During the 80s and 90s, EDM equipment was refined to eliminate a variety of problems. The main focus was on automatic adjustment to burns, as well as secondary issues like spark gap monitoring, noise filtration, and spark generation control.
The differences in terms of system evolution was significant. In the 70s, the HAZ layers would range from 0.004 to 0.010″ in thickness. The upgraded machines were capable of producing layers that were less 0.0004″. The EDM machines were also able to produce components with surface finishes of 0.5 microns. This resulted in high tolerances, and virtually no damage during the manufacturing process. Today, manufacturers who provide electrical discharge machining services are focusing on utilizing machines that can complete assignments more quickly while maintaining immense accuracy levels. This has led to the emergence of machines that can cut with wires in extremely small diameters, as well as producing accurate and clean profiles. These improvements will ensure that manufacturers will be prepared to take on complex EDM machining services for aerospace applications.
