The advanced tool design that combines a strong insert structure, a durable cutter body, secure mounting and progressive Sumo Tec carbide grades, provides the customer with an innovative solution for 45° face milling operations.

“However, this was far from the result that we had anticipated,” Miller said. “We examined the inserts under our magnifying loupe, but couldn’t see any particular failure mode.” Then Miller and Henige decided to take a good hard look under the microscope, which provides 60 times the optical power of the loupe. This closer inspection revealed that there was an edge-chipping problem. The chip flow was eroding the back of the land on the MF4. By the wear pattern, they also noted that a larger nose radius would help increase edge strength. As a result of this analysis, they recommended that Main Manufacturing increase the feedrate to 0.016 ipr using a 0.0468-in. radius. Because they didn’t see any other heat-related problems, they left the cutting speed at 650 sfm.

The inserts are produced from the Sumo Tec carbide grades. They are secured in their pockets by angled screws that provide rigid and highly reliable clamping. The mills are available in a wide-diameter range 50 to 315mm.

Main Manufacturing had been a long time user of tools from Seco Tools. Coincidentally, Seco had recently launched its new TM4000 Duratomic turning grades for stainless steel and was in search of a demanding interrupted-cut application. Seco’s sales and application specialists Joel Henige and Todd Miller asked if they could give the new grade a try. Seco Duratomic coatings rely on an alteration in the crystal structure at the atomic level, and have consistently provided both improved toughness and wear-resistance. In lab tests, the TM4000 construction had shown to improve resistance to crater wear and edge breakdown substantially.

“We initially decided to run the TM4000 using the same parameters as a competitor’s tool,” said Seco’s Miller. “But, to everyone’s surprise, TM4000 performed no better than the competitive insert.”

• Octagonal double-sided insert • Six cutting edges for machining up to 5mm D.O.C. • Outstanding durability • A wide wiper for high surface finish • Great economy regarding price per cutting edge

For example, Main Manufacturing in Grand Blanc, Mich. – a family-owned business that produces hydraulic flanges and components – was experiencing short tool life and reduced productivity due to interrrupted cuts when machining high-pressure flanges from 304 stainless steel. “The severe interrupted cut was definitely affecting tool wear,” said Main Manufacturing’s plant supervisor Terry Bettinger. “We were only able to achieve about 1.5 parts per insert due to edge chippage.”

Interrupted cuts can be tough on tools. The pounding tools take during interrupted cutting frequently leads to severe edge wear that cuts short tool life. However, by carefully analyzing the tooling wear pattern and making the appropriate grade and geometry changes, the ravages of interrupted cutting can be overcome.

Since the presence of coolant, which was water in this case, can increase the thermal cracking problem, the team decided to run the application dry to see what would happen. This change doubled tool life yet again to achieve 15 parts per corner, and now the failure mode was simply due to normal abrasive flank wear.

“We went from removing 3.6 to 12.483 cu-in./minute,” Bettinger said. “With our in-cut time reduced by one half, our part output increased from 17 pieces per hour to 54 pieces per hour. The improvements were beyond our expectations.”

• Versatile face mills carrying inserts with eight cutting edges for up to 8mm D.O.C. or inserts with 16 cutting edges for 5mm D.O.C. • Advanced cutting geometry that reduces cutting forces, and by extension power consumption, resulting in smooth cutting • Well-secured inserts by means of angled screws • Coarse and fine pitch configurations of the tools • Coolant holes (in up to 125mm cutters), directed to each cutting edge, for efficient cooling • Highly economical solution regarding price per cutting edge • Excellent performance under various machining conditions and interrupted cutting • Productivity – high metal removal rates • High process reliability

“We were pleased,” said Main Manufacturing’s machinist Craig Bendle. “Productivity doubled relative to our original setup, and tool life jumped to seven parts per corner, which was seven times better than we were getting.”

Iscar has expanded its popular Helido 800 line by introducing effective new face mills SOF45-R18 with 45° cutting edge angles.

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However, Henige and Miller weren’t done with their analysis. Another pass under the microscope revealed that the failure was now being caused by thermal cracking. “Large differences in temperature between the cutting edge and the insert can cause cracks perpendicular to the cutting edge,” explained Henige. “Interrupted cutting applications such as this one tend to generate high heat when in the cut, causing these temperature fluctuations.”

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The versatile face mills can carry in the same pocket either the S845 SNMU 18 square, double-sided insert with eight cutting edges or the ONMU 07 octagonal, double-sided insert with 16 cutting edges.

The flange starts out as a 2.25-in. by 1.5-in. rectangular plate, which is rough-faced down to a hub in the center of the part. The company was taking three passes at 0.100 in. each and a final pass at a depth of cut of 0.050 in. The job was running on a Doosan 240 CNC lathe at 300 sfm and a feedrate of 0.01 ipr.

Intended for machining mainly steel and cast iron components at high metal removal rates, the new face mill family offers users an extremely cost-effective tool for productive milling across a range of cutting conditions.

The main advantage of MF4 is its positive cutting angle, which significantly reduces cutting forces to allow for higher cutting speeds and increased productivity. With the MF4 and the enhanced cutting data, the team was able to triple tool life and complete three parts.

“We knew that TM4000 was capable of high machining parameters,” said Henige. “So we upped the cutting speed to 650 sfm using the new MF4 chipbreaker, which is designed to provide consistent chip formation and breakage in stainless steel turning and other ISO materials.”

• Square double-sided insert • Eight helical right hand cutting edges for machining up to 8mm D.O.C. • Strong and durable construction, positive rake face, resulting in low power consumption and smooth cutting

The result was that Main Manufacturing saved 85 percent in cost as well as reducing machining time by 52 percent. “But even more exciting,” said Main Manufacturing general manager Bob Mackey, “is that we can take what we’ve learned from this experience and apply TM4000 to hundreds, maybe even thousands, of other similar jobs that we run.”