Get'em Tiger

March 1, 2003
A new insert proves that its good looks aren't just for show.

A new insert proves that its good looks aren't just for show.

Milling inserts

Turning insert

Indexable drilling inserts

What sets Tiger.tec inserts apart from other coated carbide inserts is a black aluminum-oxide coating that provides wear resistance teamed with a golden titanium-nitride coating that indicates wear.

Walter Waukesha's Tiger.tec inserts cut cycle times in half for this cast iron submersible pump.

A pump manufacturer reports that Tiger.tec inserts cut at speeds and feeds up to 4 3 faster than its previous tooling.

Black and gold. Sure, it's a striking color combination for a cutting tool insert. But beyond the flashy looks of the Tiger.tec insert is a solid performer, touts Walter Waukesha, Waukesha, Wis. The cutting tool manufacturer says the pairing of two coatings—one functional, one "indicating"—not only gives Tiger.tec tools their distinctive look but also provides performance benefits for cast iron machining and even mild-steel applications.

The Tiger.tec inserts start with a tungsten-carbide substrate, onto which goes a titanium-nitride coating that acts as a bonding layer and eta-phase barrier. Next, Walter applies a titaniumcarbonitride layer, followed by an aluminum-oxide one. The aluminum-oxide layer forms an intermediate layer with the titanium carbonitride. The intermediate layer is of a lattice composition, which produces an incredibly strong connection between the coating layers.

The black aluminum-oxide top coating protects the inserts from tribochemical wear. This coating allows the inserts to run at high cutting speeds and feeds and greatly extends tool life over comparable tools, reports the company.

"Aluminum oxide has a low chemical solubility and low diffusion against cutting forces and the chips flowing over it," says Patrick Nehls, product manager of milling and drilling for Walter Waukesha. The end result is improved chip load for freer cutting and less wear and tear on the cutting edges, he explains.

Walter applies the next layer, a titaniumnitride coating, to the periphery of the inserts. This golden "indicating" coating simplifies wear detection because operators immediately see wear on cutting edges. "This helps operators tremendously," says Nehls. "It's often dark inside a machine, making it hard to check tools. With the golden area on the Tiger.tec inserts, operators can easily spot wear."

Opening to rave reviews
Tiger.tec products, which include face mills, end mills, indexable drills, slotting cutters, copy mills, boring tools, and turning inserts, have only been on the market about a year. But shops using them are reporting good results. Such is the case for a pump-manufacturing facility in North Carolina.

The company uses Tiger.tec in several applications. However, its greatest success to date has been face milling a fixed-pocket gear pump. The company is not only cutting much faster than it was previously, but it is also extending tool life and increasing part accuracy.

The cast iron submersible pump has two covers. The front cover, in particular, is a challenge because the company has to maintain parallelism with the bottom of the pocket in correlation with the mounting face of the cover itself. The job also requires a flatness of less than five-tenths over the entire surface—roughly an 8-in. diameter—and a surface finish of 32 Ra or better.

"The two halves of the pump are sealed with an O-ring, so finish is critical to keep the pump from leaking," says the company's senior manufacturing engineer.

The pump manufacturer previously made two roughing passes on a VMC using 4-wiper-insert carbide cutting tools. It then transferred the part to a surface grinder to rough and finish grind both sides to obtain the required flatness, parallelism, and surface finish. Total machining time per cover was 32 min.

The company had been using small-diameter roughing and finishing mills, but it found these tools inadequate for the job at hand. But Tiger.tec has improved chip load, maximizing both machine and cutter performance. The tools also helped with another problem—machine capacity. With its previous setup, the pump manufacturer could only produce 8 to 10 pumps/day.

Along with the switch to single-wiper Tiger.tec face mills, the company also moved its cover machining to an HMC equipped with new fixturing. The HMC has two advantages over the VMC in this operation: better positioning tolerance and higher machine capacity. But the Tiger.tec tools are the real story, says the manufacturing engineer. Not only do they cut at speeds and feeds up to 4 3 faster than the previous tooling, their tool life is up to 3 3 longer.

An extra advantage to the Tiger.tec tools is that the company could skip the grinding step for the front cover. This cut cycle times down to 15 min—more than half of what they were before. "We found that with the proper speeds and feeds, we could obtain the flatness, surface finish, and parallelism with the finish mill versus the grinding operation," says the company engineer. "We achieved our fivetenths flatness along with a 22-Ra finish and a parallelism of one to two-tenths to the bottom of the pocket. With further modifications, we're now getting about a 15-Ra finish."

On top of these benefits, the company has gone from four operations—two rough cuts and two grinding passes—on two machines to a rough and finish cut on one machine. One setup is all that is needed.

Besides the front cover, the company also rough cuts the rear cover using the Tiger.tec face mills. However, the grinding step can't be skipped in this application. That's because the cover is thin — about 1/8-in. thick—with two channels running the length of the part.

"With parts that thin," explains the engineer, "we get a lot of part flexing, so we're still grinding the rear cover." Even so, the Tiger.tec tool has greatly increased production of the part. According to the engineer, "Tiger.tec has cut the cycle time 40% on the grinding operation because we've gone from grinding ten-thousandths per side to just three-thousandths."

The real cost
Obviously, Tiger. tec's performance impacts the bottom line when it comes to per-piece productivity. "First of all, we're seeing tool-life improvements of 50%, 75%, and even more," reports Nehls. "And the inserts are also improving cutting performance and profitability for our customers."

The math is simple, he points out. While tool cost is roughly 4% of total manufacturing expense per piece, increasing cutting data by 20% cuts overall costs by 15%. "Increasing cutting data means we want to run faster and run longer between insert changes," he explains. "And shops get both these benefits with Tiger.tec."