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Faster EDM Performance with New Hybrid-Coated Wire

High-precision pneumatic valve manufacturer achieves better finishes in less time, with reduced power consumption and less wire breakage.

Cincinnati-based Clippard supplies valves and other high-precision components for industrial fluid control, and continues to operate as a vertically integrated manufacturing business, as it has been since 1941. Clippard’s two, ISO-certified manufacturing plants in Ohio produce its extensive catalog of standard and custom products in various metal and thermoplastic materials using 12-axis CNC Swiss machines, CNC milling centers, and CNC wire EDM machines. They also perform numerous post-finishing operations, including anodizing, EN plating, and thermal deburring.

Recently, after discussions with EDM supply distributor, a proprietary, hybrid-coated brass wire was presented to Clippard director of operations Robin Rutschilling and CNC/EDM programmer Trevor McCoy. Global Innovative Products’ Plasma hybrid-coated brass wire is comprised of a gamma-phase intermetallic zinc alloy-coated wire with a brass core. This proprietary GIP innovation had been proven effective in numerous lab tests but needed real-world production validation. Barry Ramsay of Global Innovative Products (GIP) and GIP application engineer Brad Hansard approached the team at Clippard.

The product had been found suitable for operation all types of wire EDM machines, with excellent auto-threading capability and increased performance, even at conventional brass wire settings. Ramsay felt confident it would outperform the EDM wire Clippard had currently been using, including other GIP wire products. The new product is available in 0.008-in., 0.010-in., and 0.012-in. (20-mm, 25-mm and 30-mm) diameters, so Ramsay offers Clippard a supply to test on one of its FANUC wire EDM machines.

Gamma-phase brass is a brittle intermetallic alloy (Cu5Zn8) with a high zinc content (approximately 65% Zn) which also can be synthesized by a diffusion anneal. However, when such coatings are wire-drawn subsequent to the diffusion anneal, the coating will fracture due to its brittleness and redistribute around the wire circumference, creating a discontinuous layer sometimes described as a “porous layer”, that promotes turbulent flow enhancing the flushing of debris.

However, zinc enrichment created at the surface combined with the elevated melting point of CuZn gamma phase (approximately 800ºC/1472ºF) are the biggest factors contributing to the performance of gamma-phase brass-coated wire.

The arrangement between Clippard and GIP actually began in a somewhat unconventional manner, as Trevor McCoy recalled. “We have an Ocean hole popper (electrode/sinker EDM) and the circuit boards needed repair. Brad (Hansard) was able to do that kind of work, which I knew from previous experiences with him. So, he proposed exchanging the board servicing for the opportunity to test the GIP hybrid Plasma wire. (That) seemed reasonable to us, so we agreed.”

The FANUC wire EDM in the Clippard shop seemed an ideal candidate for GIP’s tests as well, as Barry Ramsay noted. “We knew they were running all types of materials and some very high-precision tooling used in their own machine shop for the production of various pneumatic components with very tight tolerances. It seemed a very good place to test our new wire, which had been proven out on our own EDM’s at GIP.”

He added that it was a handshake deal, a “classic collaboration between two companies for their mutual benefit,” and pointed out that application engineering supplied by GIP further enhanced the use of the product at Clippard, as the test learning process information was shared without reservation. Both companies benefited.

In this test case, many of the components were being run for special parts being produced by Clippard for robotic arm articulation.

The testing yielded positive results immediately, as McCoy noted the completed parts were holding tolerances under one-tenth, with a microfinish that was very important for the application.

“We do a lot of custom work for our own use, over 50% of my production in EDM,” McCoy said. “Some of the hard tool steels are difficult to drill and we also run various others. The jobs require a lot of set-up time and fixturing, so run time, finish and wire breaks all are critical for us.”

There were three goals for this proprietary wire testing sequence, according to Barry Ramsay. “The characteristics of the Plasma wire in production on the FANUC machine at Clippard were important, as the flushing of their precision components directly impacts quality.

“Further, we had our own test results galore — but needed an outside house to validate what we were seeing,” he continued. “Lastly, we just wanted to help our friends at Clippard, who had been so cooperative and, in this case, needed our help with those circuit boards. It was a classic win-win for both of us, as all three goals were met.”

Multiple parts were EDM’d during the testing of this Plasma wire, with full comparative data tracked on the test wire versus conventional brass. For example, one tool for a medical part was produced in :56 vs. 1:05, with five skim passes — a 16% improvement in overall production.

McCoy noted: “We could apply more power to run faster. The GIP product consistently outperforms premium brass, based on my experience with both (products) now.”

He also cited a very practical advantage. “The Plasma wire is as clean as conventional brass,”  he said.

And, according to GIP’s Barry Ramsay, the cost of the new hybrid-coated brass wire also is competitive, so there’s less of a premium attached to achieving enhanced results.

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