Unattended, Short-Run Production Work Spurs EDM Shop's Growth, Productivity

Advanced Machining Corporation (Salisbury, North Carolina), a tool and die shop, believes that a mix of CNC EDM systems running 20 hours a day—unattended—on shortrun production work and one-of-a-kind custom work is the formula for success. As a result, the shop is expanding its business.

"A few years ago, most everything we did was one-of-a-kind, custom item things," says Keith Felts, the company's co owner. "Now we're doing more repeat tooling and getting into shortrun production and prototyping. Running more parts that are short to medium volume with our EDMs has meant the need to increase our EDM capacity with automated machines that will run unattended, producing parts around the clock with just one manpower shift."

The move into shortrun production projects is changing Advanced Machining's product mix, and Bobby Miller, Advanced's other co-owner, says it's good to be making this transition. The shop continues to receive custom, one of a kind jobs, but it's also garnering an increasing number of production type jobs that demand attention only until the first successful production parts come off. The latter situation is attractive, Mr. Miller explains, because at this point, it's just a matter of letting the machine run to process the parts.

"By having a mix of the two," he says, "while we're doing the brain work on the really tough, complex one of a kind parts, we've got production work out there keeping the machines running. This allows us to be more profitable."

Since Mr. Miller and Mr. Felts opened their doors 13 years ago, Advanced has tackled work in tough material like Inconel, titanium, carbide, high speed and stainless steel, and the powdered metals. That kind of work also plays to one of the strengths of their EDM specialty.

A Westinghouse unit in WinstonSalem, North Carolina, recently requested that Advanced Machining apply its expertise to a hammer die project. Made from a 40-pound block of Inconel, a hammer die is used in a forgingtype operation in which stainless steel is pounded into turbine blades. The dies measure 8 inches by 12 inches by 4 inches thick with very large surface areas. The dies take enormous abuse—so much so that they become deformed during the forging operation for which they are designed.

"Originally, Westinghouse wanted us to mill the dies back into shape on our machining centers," Mr. Miller says, "which was feasible, but Inconel is really tough stuff; it just eats up cutters and spits them out. We felt it would be more economical and more trouble free to build graphite electrodes. Then we could just sinker the surfaces back into shape."

Some of the turbine blades being processed are 6 feet long. The hammer die strikes the blade, progressing from one end to the other. After the die wear and deformation reaches a certain level, Advanced restores the surface with the EDM process, making it into a usable die once again. This is an advantage to the customer, since in the past, the worn and expensive dies could only be discarded.

Picking up projects such as this hammer die caused Advanced Machining to need another die sinking system. "We needed more capacity, and it was very important that we add a machine that had the automation level we've become accustomed to," Mr. Felts says. "We needed the automatic electrode-changing and the ability to process multiple workpieces while the machine ran unattended."

Mr. Miller adds that "being able to run unattended makes a tremendous difference. It's really the key to profitability because you make your money at night."

So Advanced turned to the Agie Mondo Star from Agie Charmilles. "It has 85 percent of the features of a full-fledged CNC machine, but in reality it can do 99 percent of what most people use a CNC sinker for," says Mr. Felts. "The things that are missing are not needed, and if present, they would add lots of cost without providing us with any usable benefit, for the most part."

Advanced also purchased an Agiecut Classic wirecut EDM system. "As for the Classic, we have become very accustomed to Agie's wire machines and their capabilities," Mr. Felts says. "The Classic bears a lot of similarities to the Mondo in that it's very inexpensive for an Agie, which is traditionally an expensive machine. There are some things it does not have that a top-of-the-line Agie would, such as submerged cutting, and for some of the work we do, submerged cutting is very important—even essential.

"However, there's a very large percentage of our work that having submerged cutting available would in no way enhance. So it's something we can live without in this machine [the Classic]. At the same time, it has the accuracy, the finish, the automatic wire threading—all the things we need to be productive. It has a lot of good Agie things we like at much less cost."