Cutting Graphite and Cycle Time

 

UTTING GRAPHITE AND CYCLE TIME
Howmet Tempcraft Uses Time as a Competitive Weapon 

High-speed graphite milling helped bring Howmet Tempcraft’s technology into the 90’s—and its bottom line into the black. After a string of unprofitable years, this investment casting maker had to find a way to move more product out the door faster or risk succumbing — permanently perhaps — to competitive pressures. Nothing short of a major makeover would do.

After putting everything from order entry to delivery under the microscope, it was clear that the company needed better, faster, smarter equipment if it were to be competitive again. "Technologically, we were still in the 70’s," admits Raymond G. Seuffert Jr., the manufacturing manager for Howmet Tempcraft’s Tooling Business Center (Cleveland).

The company’s search for equipment that would bring them into the 90’s and beyond, brought a team to Makino (Mason, OH) for demonstrations of that company’s high-speed vertical machining centers. "At Makino, we saw a machining center that would take us from 3 to 25 horsepower, from 5,000 to 15,000 rpm, and from 20 to a 300 plus inch per minute feedrate," says Seuffert. "That’s the kind of speed we knew we needed to be competitive again."

Given that nearly 75% of Howmet Tempcraft’s work is complex, 3-D electrodes, Makino’s SNC106 graphite milling machine also caught the team’s attention. They reasoned that the SNC106 — with its speed and automatic tool changer — would reduce cycle time and, therefore, contribute to the bottom line.

The high-speed vertical machining centers and the SNC106 arrived in early 1994 and all the appropriate staff were thoroughly trained with assistance from Makino. "We were all pumped and anticipating a significant gain, but at the time we didn’t know it would be quantum," recalls Seuffert. "For instance, we just shipped a tool that used to take us 40 weeks in less than eight. And we beat our deadline by three days!"

The speed and unattended nature of the vertical machining centers have freed up time and manpower so Howmet Tempcraft could accept new projects. And Seuffert says there’s not been a problem finding work to keep the men and the machines busy. The demand has even created the need for two shifts and has nearly doubled employment to 90. He notes that in addition to having the capacity for more traditional work, the new machining centers have also permitted Howmet to bid on non-traditional projects as well, such as plastic injection molds, die cast dies and others.

"It was nearly impossible to compete in the consumer market before; but we do now," says Seuffert. "We can’t necessarily do so on the basis of price, but we can on speed. When a manufacturer has a 20-week assignment that needs to get done in six or eight, they call us."

Howmet Tempcraft is also enjoying equally impressive cycle time reductions with its electrode production. Seuffert notes it used to take three to five weeks to cut a set of complex electrodes, "But with the SNC106, it’s not uncommon for us to cut a set in under 24 hours."

Why has the new graphite mill made such a difference? "Our SNC Series graphite milling machines employ high-speed data transfer, so you can accurately feed the 15,000 rpm, air-cooled and pressurized spindle at speeds up to 200 inches per minute," explains John Shanahan, Makino Die/Mold Product specialist. "Thanks to their high-speed and accuracy, our graphite milling machines will manufacture electrodes with superior geometry, while dramatically reducing or eliminating costly manual finish time. The result is an electrode that represents the finished cavity shape, ready for the EDM process in record time."

There’s another aspect of the SNC Series which is highly prized by those who have machined graphite in the traditional way. "Our SNC machines perform high-speed milling in a sealed enclosure with an integrated vacuum system, effectively containing graphite dust particles without danger to the machinist or to the machine’s sliding mechanisms," notes Shanahan.

The bottom line benefits of faster cycle time are evident in Howmet Tempcraft’s ledgers. In 1994, the company logged efficiencies at 106% and equipment utilization rose from 79% the previous year to 97%. The result was $9 million in sales in 1994, a 50% increase over 1993. And Seuffert says 1995 looks even better, with sales projected to exceed $11 million.