HOUSE OF EDM
Norman Noble dramatically reduces consumable costs while increasing quality.
"We’ve never seen a part come out so perfect," said Mark Moore, EDM manager at Norman Noble of Cleveland, Ohio, as he walked through a row of EDMs made by three different manufacturers. "We have 187 machine tools, 26 of them EDMs. But that first part out of the Makino floored me."
In Moore’s hands was a large block of hardened D2 steel, cut into a shape that would make a CAD programmer’s head spin. At Norman Noble, machining complex parts for medical and aerospace applications is routine — but this one presented a challenge.
The piece Norman Noble was charged to produce was certainly complex, but was also bigger than they were used to for a wire EDM piece. The height of the 15-pound EDM wired block ranges from five to three inches, curving along one side. Beyond the height irregularities, it has dozens of holes and ribs, all cut at varying angles and tolerances of ±.0002 inches.
"Everybody who looked at the drawings was amazed at how complicated it was," said Moore. "We knew we were up to the challenge, but also knew it would probably require hours of hand-finishing to get it right. And it did, until we got our new EDM — a Makino SP43."
A Company of Excellence
Nicknamed "The House of EDM", Norman Noble takes electrical discharge machining very seriously. The company slogan is "Our name means excellence", and it shows in everything they produce.
Pride in uncompromising excellence has been a staple of Norman Noble since its founding in 1946. Today, two generations of the Noble family maintain this guiding principle as they lead the company — and the industry — with state-of-the-art capabilities and exceptional service.
This dedication to quality shines through in their unwavering commitment to the most current technology and expertise. When the need arises, the company does not hesitate to invest in the most advanced equipment available. And to ensure its products meet superior standards, Norman Noble’s quality controls are second to none.
Over eighty-percent of Norman Noble’s business is from major medical manufacturers, from pieces only a few millimeters in size, to the complex medical part its Makino SP43 is producing.
"To compete with the guys who are making parts overseas, we have to make a better part faster," Moore explains. "With the best equipment and expertise in the world, we easily can compete in the world market." Norman Noble has so much business lately that they’ve expanded to a 120,000 square-foot facility in the past year.
A Complex Piece
"Do you have any idea how hard it is to cut something that can’t lay flush to the surface of the bed?" asked Jerry Mismas, a Norman Noble EDM operator with 12 years experience, running his finger along the edge of the piece to show the varying height levels.
"And it has to be perfectly straight and most of it to a tolerance of 0.0002 of an inch," added Joe Caine, a Norman Noble operator and EDM programmer for over 15 years.
With such a large and complex piece, the "House of EDM" found itself burning up a lot of production hours getting it right. The older EDM machines would cut the piece and then run skim pass after skim pass making everything straight.
Once the wire EDM had done its best, Mismas would have to take over and hand-finish within the angular tolerances of 0.1 degrees, and cuts within ±0.0002 inches. On top of that, a 16 micro finish was required.
Caine and Mismas ran the part on every wire EDM Norman Noble had in the shop, including machines less than a year old. The parts would come out with a finish of 20-25 microns, forcing him to spend about six-hours per piece polishing to meet the 16 micro finish requirement.
Norman Noble needed to reduce bench time to make the process efficient. Then one day, in what would turn out to be a lucky break, one of Norman Noble’s EDMs needed to be replaced.
The shop already had a Makino KE-55 manual/CNC knee mill, but had never tried a Makino wire EDM. Beyond just replacing the failed machine, Moore wanted to expand their capabilities and make the shop more efficient. Moore decided to give Makino’s SP43 a shot to see what it could do.
"Our quality control people told me the first piece off the Makino was one of the best parts Norman Noble had ever cut," said Moore, still holding the finished chunk of steel. With only two months of training and a few test cuts, they had successfully cut their super-complicated part to the exact tolerances and at a 16 micro finish, with no hand-polishing.
After a few more months of tweaking, their Makino was churning out parts with an eight to 10 micro finish.
The New EDM
When Moore started looking for a new wire EDM he came across the Makino SP43. The SP43 is a solid workhorse, with the ability to handle a workload of 1,760 pounds (800 kg). The machine weighs a sturdy 5,940 pounds (2,700 kg) with a footprint of 8.5 x 8.5 x 7.63 feet (2,550 x 2,550 x 2,290 mm). The dual-action doors (two doors in one) and table height of 38.8 inches (970 mm) are noticeable design features for operator convenience.
The SP43 has an X-, Y- and Z-axis travel of 18 x 12 x 12.8 inches (450 x 300 x 320 mm) with a maximum workpiece size of 29.2 x 20 x 12 inches (730 x 500 x 300 mm). This machine offers the use of wire diameter sizes from .004 inch to .012 inch and taper cutting capability up to 15 degrees.
Makino’s SP43 utilizes proprietary control software, WireWizard®. The software has three main graphical components designed for maximum throughput — programming, set-up and run — which provide the basic needs for any application. It uses this logical approach by actually prompting the operator through the process. Simple operation makes the software learning curve negligible, providing an easy transition for operators.
WireWizard includes: PowerWizard® adaptive control to manage discharge current and maintain an optimum spark gap; BellyWizard® technology to improve straightness of the initial cut, reducing the need for skim passes; and CornerWizard® geometric control system that allows for superior shape accuracy, providing tighter control of small internal corner radii.
Setting up a part is easier on the Makino, thanks to the big table and fast movement, according to Mismas and Caine.
"Check out how fast this thing moves in jog mode," said Mismas as he grabbed the hand control and checked to make sure the piece was flat, squared and centered on the Yaxis. "This takes forever on the other machines," he said, waving his hand at the long row of EDMs.
The Makino’s tank and table size has also allowed Norman Noble to take on parts that they otherwise might not have been able to easily machine. This includes a recent piece 10 inches tall and 12 inches in diameter, made of titanium for the aerospace industry.
Mismas and Caine have used many other machines, but found they were comfortable with Makino’s WireWizard® software interface within a few weeks instead of a few months. This proved especially helpful with the complex medical part they intended to cut, since it required thousands of steps with very complicated programming.
Beyond The Part
Beyond the part coming out of the Makino flawlessly, saving them at least six man-hours per part, they also saw a dramatic reduction in wire usage.
"I thought the Makino’s wire feeder was broken when we first got it," said Moore. "The wire spool was just barely creeping along. It looked like it wasn’t feeding fast enough to work." But the Makino was cutting the parts perfectly while using fifty percent less wire than their other wire EDMs.
"The real time savings came in resource hours and machine uptime," comments Moore. Total machining time was reduced by 20 to 25 percent from older machines and 5 to 10 percent from other new wire EDMs the company purchased a few months before they bought the Makino. "I can have my guys throw the part on the Makino and forget about it for the 50-hours it takes to machine, so they can work on other projects."
Almost all bench work was eliminated, and wire replenishing is necessary only half as often. In addition, Moore says the wire doesn’t break, so the machine can run unattended without worry, a big advantage for a shop as busy as Norman Noble.
"Taking care of the Makino is easy," said Mismas. Filter and coupling changes are quick and painless, V-guides are easy to replace and position, and he noted the rear seal hasn’t leaked a drop, which he says is an annoying problem on some of the company’s other EDMs.
Mismas attended training at Makino’s Auburn Hills, Michigan, Die/Mold Technology facility. "These guys knew everything about wire EDM. They answered all my questions and even made a couple of guys who’d never touched a wire EDM before look like pros."
Between the two days in Michigan and two days that Makino’s installation team spent with him at Norman Noble setting up the machine, both Mismas and Caine felt confident they could do better with the Makino than with the other wire EDMs in the shop.
"I thought some of the tolerances and finishes Makino said they could achieve were just sales-pitches, until I actually burned some metal," Caine said. The corners were crisp and radii perfect.
Since completing the training, Mismas has contacted technical support a few times. He has been impressed with Makino’s depth of knowledge and fast response. "A lot of manufacturers don’t even call you back when you’re stuck — I always have an answer from Makino within an hour."
"And check out these manuals," Mismas said, grabbing two binders off a shelf near the Makino. They are the most straightforward, useful manuals he says he’s ever seen with a machine tool.
After seeing what the company’s new wire EDM could do, Moore ordered a second SP43. Norman Noble has dedicated this second machine to cutting only the super-complicated part, given that the process using the Makino is nearly hands-free and runs 24-hours a day.
Today, Norman Noble is effortlessly producing the complex medical piece that seemed to consume so much productivity and so many hours just a few months ago. Moore has been able to assign his people to other tasks instead of spending hours bench polishing the piece, and the Makino wire EDM is consistently cranking out parts well within the tolerances required, with an eight to 10 micro finish.
"The Makino lets us machine pieces we thought weren’t possible without hours of hand-finishing," said Moore. "Now we’re doing it everyday, and quality control says they’re some of the best parts coming out of the shop, thanks to our new EDM."