The use of electrical discharge machining, or EDM, is spreading as manufacturers need more precisely cut workpieces, often made from tough to machine materials. “EDM has a number of advantages, particularly when applications are complex, utilize harder to machine materials, or require a fine finish,” said Evan Syverson, marketing coordinator for Sodick Inc. (Schaumburg, IL). “It is not affected by material toughness and poses little risk to delicate workpieces.”
EDM is highly automated and uses electrical discharge sparks to cut and machine parts.
“As the skills gap grows, and as increasingly tough and exotic materials come to dominate the market, the ability to cut a wide range of materials with minimal manned labor becomes even more essential,” Syverson said.
The technology is spreading from molds and dies to finished production parts.
“Utilization of the EDM process has remained strong for the die/mold construction market, but it has been growing in use and acceptance for precision machine applications,” said Brian Pfluger, EDM product line manager for Makino Inc. (Mason, OH).
At MC Machinery Systems Inc. (Wood Dale, IL), part of Mitsubishi Corp. (Tokyo), “Our sales indicate that over the last 15 years there are not so many new industries that are moving to EDM for the first time, but rather industries like medical and power generation that have expanded their use of EDM in their manufacturing capabilities significantly,” said Alan Hallmann, North American sales manager.
Medical devices and implants, in particular require precision parts. Demand for such products has remained strong while demand in other markets have softened. The aerospace and firearms markets also have invested in EDM, according to executives.
In general, Hallmann said, “Unmanned machining capability, predictable results for close-tolerance work and exotic materials lead the demand for more EDM.”
A whole range of tough materials, including titanium and Inconel, are being used more in manufacturing. Sinker, or die-sink, machines discharge electricity from shaped electrodes into parts submerged in fluid. Wire-cut machines send sparks to cut parts submerged in deionized water.
With EDM, there is “no limit in hardness as long as the material is electrically conductive and we can cut it,” said Gisbert Ledvon, director of business development for GF Machining Solutions LLC (Lincolnshire, IL), which is part of Georg Fischer AG (Schaffhausen, Switzerland).
What follows is a look at strategies of different makers of EDM machines.
Sodick is adapting to the increasingly digitized manufacturing world of the Internet of Things (IoT), where machines communicate with each other, and operators use smartphones to monitor production.
“We have ensured that our machines are compatible with the latest in IoT technologies, such as MTConnect, which improves overall facility productivity,” Syverson said. “EDM is an ideal candidate for Industry 4.0 and the IoT as the process is already highly automated. These market shifts have set the stage for a major leap forward in productivity in EDM facilities.”
Industry 4.0 refers to IoT and other digital technology being implemented in factories.
Eight years ago, Sodick released a piece of equipment that is a hybrid EDM and waterjet machine. “What we learned was that hybrid EDMs have a limited scope of ideal applications to justify the cost of this technology versus traditional equipment,” Syverson said. “The best improvements in this regard are production process improvements which make use of unmanned EDMing while additional machining is done separately at the same time.”
The company also is moving to improve EDM’s ability to increase production, he said.
“EDM output has continually increased as we improve discharge wave-shape manipulation for optimal cutting,” Syverson said. The company also has started developing generators “with separate optimization for coated wire,” he said. The company says that can mean faster cutting speeds compared with plain brass wire.
Makino has been updating its product line as EDM demand increases.
“Makino has revamped our entire EDM product line over the past three years,” Pfluger said. The company, for example, has brought out its Hyper-I control system, designed to work with its sinker and wire machines instead of having different controls for each. It was designed “to support the needs of operators of all skill levels to become more efficient and productive,” he said.
Other product enhancements include Makino’s HyperCut generator technology for sinker EDM that reduces wear on electrodes and “low wire consumption” technology for its wire machines.
In 2017, Makino will introduce a remote diagnostics system for EDM as part of its IoT strategies, Pfluger said.
Another change involves Makino’s relationship with its customers.
“Makino has seen an increase in share-key and turnkey requests” where “Makino takes responsibility over all or certain aspects of the manufacturing process,” Pfluger said. “In many cases, customers have requested Makino take full responsibility of the entire manufacturing process.”
The executive said the idea of hybrid machines combining EDM with other technology “is still somewhat unrealistic. The issue with combining machine processes into one machine is that it becomes very specialized to one specific application, or the end result is a machine that is not 100% effective at either process.”
The company is optimistic about EDM’s prospects.
“The improved ease of usability of EDM has allowed customers to produce completed parts by EDM without the need for post-machine processing,” Pfluger said.
At Belmont Equipment & Technologies (Madison Heights, MI), the roster of customers is mostly the same. But those customers have different priorities.
“We have more customers interested in maximizing floor space through compact design machines,” Bob Ianitelli, president and chief operating officer, and Frank Restaino, senior product engineer, said in a statement in response to questions. “Another priority has been new ways of looking at ergonomics in the sense of productivity.”
Belmont estimates that 80% of the machines it sells “are customized with anything from machine specifications, to a full turnkey with tooling and part programming, to a simple custom cycle start switch,” Ianitelli and Restaino said in the statement. “Depending on the scope of the project, these customizations could take anywhere from one to 10 weeks.”
The company also is making improvements to its machines.
“Applications are becoming more complex, often the machine in the brochure won’t work [for a specific complex application] so we redesign machines” to fit customer needs, according to the men’s statement. “We also are attracting new customers through new ancillary items for the machines such as a part sensing circuit that detects absence or presence of the workpiece at critical points that minimizes costly errors due to incorrectly loaded workpieces.”
Belmont also said it’s in the “beginning stages” of Industry 4.0 technology.
“This could be very beneficial to predict unforeseen maintenance, as well as better tracking of consumable costs and workpiece variations,” the two men said in the statement.
MC Machinery said the Mitsubishi EDM machines it distributes have improved by reducing wear on electrodes.
“This is one of the most productive advancements in EDM technology on sinker EDM machines today,” MC’s Hallmann said. “By reducing electrode wear in half and improving speed, customers can now justify new equipment.”
The executive said EDM output is being increased because new machines “can burn faster and use less electrodes” and that adding “an automatic electrode changer and setting up multiple parts on the tables for more unmanned machining” also speeds production. In addition, he said, production can be boosted by “automating the machine with a robot and graphite mill to keep electrodes replenished for long runs.”
For now, MC Machinery isn’t a booster of hybrid machines.
“Currently, we don’t see combining technologies within the EDM machine to be on the immediate forefront in technological advancement,” Hallmann said. “Maybe in five to 10 years that will change but it is not clear. All previous attempts to add alternative processes to the EDM machines have not proven to be more productive or cost effective.”
“The improved ease of usability of EDM has allowed customers to produce completed parts by EDM without the need for post-machine processing.”
MC Machinery’s customization for customers include risers for tall cutting and “tank modifications for larger parts,” he said.
GF Machining also is adding improvements to its EDM lineup.
Among the changes: “New generator technology improving speed surface finishes,” according to GF’s Ledvon, as well as “automatic wire changer and optical or mechanical in-process inspection systems for wire EDM.”
Also, he said, the company is “using new digital generator technology to minimize or in some cases eliminate [not measurable] electrode wear with our iQ generator module.”
GF is moving into Industry 4.0 territory with technology for “monitoring and making adjustments to the process or preventive service and trouble shooting,” Ledvon said.
The company also is doing more customization. “We developed more dedicated machine solutions based on market segmentation,” he said. “But in general it can take up to 12 months for a very customized machine.”
This article was first published in the October 2016 edition of Manufacturing Engineering magazine.
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