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Tough Slotting Solution Was Just the Beginning of Savings for Replaceable Tip Cutting Tool

Jim Lorincz
By Jim Lorincz Contributing Editor, SME Media

At Flexco Inc. (Downers Grove, IL), finding a solution to speed up slot-milling with Chip-Surfer replaceable tip solid-carbide cutting tool from Ingersoll Cutting Tools (Rockford, IL) has led to benefits in a host of other operations as well. Flexco, a manufacturer of belt conveyor components, estimates that retooling with Chip-Surfer replaceable solid-carbide tip cutting tools has saved about $200,000 a year overall on slotting operations and the company expects to save as much again on mill-turn operations. The retooling that made all the difference involved replacing standard solid-carbide end mills with Chip-Surfer. On average, material removal rates (MRRs) for slotting operations improved 60% and tool life improved more than 3 to 1. Some mill-turn applications run faster by 2½ to 1.

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Change-out for threading Ingersoll’s Chip-Surfer replaceable carbide tip onto a stubby solid-alloy steel shank takes just seconds right in the spindle to 0.0005″ (0.013-mm) repeatability.

The machine shop portion of Flexco’s main plant has seven employees and runs 16/5 plus a Saturday shift—in addition to a lot of lights-out work. Other shops within the plant handle stamping, welding, assembly, etc.
“It’s a very capital-intensive shop with a lean staff tending several machines, with many long-cycle operations running completely untended overnight,” said Ray Lee, manufacturing manager. “Running with such a lean staff places a premium on reliable equipment and tooling.”

One look at Flexco’s mainstay jobs highlights the importance of efficient slotting. Called a bed, the workpiece is made in several different sizes. Basically it’s a rectangle of 4140 steel hardened to Rc 28–30, measuring 5–7′ (1.5–2.1-m) long and 3½” (89-mm) wide, with 58–70 transverse slots along its length. All slots measure 0.394″ (10-mm) wide by 0.375″ (9.5-mm) deep.

Previously, Flexco machined the slots with 5/16″ (8-mm) solid-carbide end mills running at 200 sfm (61 m/min), 25 ipm (0.64 m/min) in the bilinear milling mode. Typically, it took about eight hours and one tool change to complete a single bed. The slot was opened with a pilot hole to accommodate the mill, then the slot was completed in several light passes. “If we tried to run any faster, the tool just burned up and snapped off,” said Lee. “Then we had to go through a touching-off to get to dimension every time.”

Given the challenge by management to speed up the slotting, Lee called Mike Toleman of distributor QTA (Elk Grove Village, IL) to bring in a series of solutions for thorough competitive testing. Once the tests were underway, Toleman alerted Ingersoll’s Jarrett Johnson to be ready with a solution during his next plant walk-through. Up to that point, no tool in the tests had lasted through one entire workpiece.

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Retooling slot milling with Ingersoll’s Chip-Surfer replaceable-tip saves Flexco about $400,000 a year, opening slots 60% faster than previous solid-carbide end mills and lasting through two complete parts made of hardened 4140 steel.

In the Chip-Surfer cutting tool test using a 3/8″ (9.5-mm) cutter, the cycle time was 60% less than any competitor and one tool tip lasted through two entire parts. Tip replacement, right in the spindle, took just seconds, with repeatability that promised to eliminate all tool servicing time for touching-off.

“Faster removal, longer life, tool changes in seconds—we looked no further,” said Lee. “We didn’t have to.”

Flexco went operational in September 2016 with Chip-Surfer for all bed-slotting. Improvements mirrored those seen in the tests: 60% higher MRR, 2–3× tool life, and no touching off. The operation was re-programmed to eliminate the pilot drilling and feed the Chip-Surfer directly into the stock. Parameters are 335 sfm (102 m/min), 30 ipm (0.76 m/min), 0.100 (2.54-mm) DOC for three passes and 0.075″ (1.9 mm) for the final pass. Feed per tooth on the four-flute cutter is 0.0025″ (0.064 mm). Flexco runs them on its Mazak SVT vertical medium-duty machining center with water-based cutting fluids.

Ingersoll’s Chip-Surfer is a modular cutting tool with a replaceable carbide tip threaded onto a stubby solid-alloy steel shank. Tip change-out takes just seconds right in the spindle to 0.0005″ (0.013-mm) repeatability. Free-cutting geometry on the tip minimizes cutting forces and resolves them more axially than radially for greater rigidity. The tool has proven out in hundreds of slotting, T-slotting, ball milling, chamfering, threading, and helical milling operations.

Soon after Flexco’s slotting operation was stabilized, Lee and Johnson sought out expanded applications for the Chip-Surfer. They usually did it every Thursday, Johnson’s customary walk-through day on the Flexco floor. “He’s familiar with our entire environment as well as capabilities of this particular tool,” said Lee, “especially the reliability we need in light of our lean crew and lights-out operations.”

One of the most rewarding additional applications they uncovered was live milling on Flexco’s mill-turn machines. They improved such a range of applications, seven in all, such that Chip-Surfers have become permanent fixtures on two turrets of the company’s mainstay mill-turn machines. Applications include chamfering in five sizes, flats-milling, pinch-milling and hex milling on turned parts.

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Live milling with Chip-Surfer speeds up mill-turning, improving chamfering, flats-milling and especially pinch milling (shown). Machining savings in mill-turn work about match those in slot milling and Chip-Surfers have become permanent fixtures at all live stations on Flexco’s fleet of mill-turn machines.

On one cone-shaped part, the Chip-Surfers reduced machining time to 57 minutes from 2½ hours. More recently, Flexco standardized on helical milling with the Chip-Surfers to speed production of large-diameter holes. If the holes aren’t roughed out by flame-cutting, the Chip-Surfer opens them from solid. “This technique enables us to reduce the tool count, complete large holes much faster, and run the jobs on lighter-duty machines because the cutting forces are so much lower,” said Lee.

“We use the Chip-Surfers in the pinch milling mode on two Eurotech 3 turret twin-spindle lathes,” said Terry O’Mary, senior engineer. “The technique uses two cutters working simultaneously on opposing sides of the workpiece to balance cutting forces on heavy milling and turning operations in tool steel, S7 and 4140.” He added that the Chip-Surfers enable very heavy passes and a single tip handles a variety of cuts to keep the tool count down.

Located 90 minutes away from Ingersoll headquarters in Rockford, Lee and his crew regularly attend the toolmaker’s tooling seminars. “We always come back with a better idea for one of our operations,” said Lee. “We’re a small shop within a large enterprise, so we don’t have the time to optimize everything ourselves. We need our suppliers for solutions, not just hardware, and Ingersoll excels at that—both here on our floor as well as at their seminars. That’s why more than 60% of our tooling is by Ingersoll.

“Flexco deserves credit for being willing to listen and learn,” said Johnson. “Many small shops could benefit from their experience and open mind toward innovation.” Introduced in 1998, the Chip-Surfer product line has proven out in thousands of applications in steel, aluminum, and titanium at hundreds of sites, according to Ingersoll. Key applications include cavity milling, corner rounding, chamfering, plunging, slotting, drilling, engraving, threading, and helical milling. More than 30 different application-matched tip styles are available, and all are interchangeable on the same shank. Shanks are available in alloy steel and, for extra rigidity, tungsten carbide.

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