Another advance in the indexables field is Iscar’s development of proprietary insert grades designed for machining heat-resistant superalloys used in aerospace applications. Stusak claims these insert grades normally last about 20 percent longer than a typical grade in Iscar’s portfolio. Though he wouldn’t discuss the specifics, he did reveal that there are alloying elements in the carbide substrate of the inserts that give it a higher hardness in elevated machining temperatures.

Joe Thompson has been covering the Canadian manufacturing sector for more than two decades. He is responsible for the day-to-day editorial direction of the magazine, providing a uniquely Canadian look at the world of metal manufacturing.

Solid-carbide ball-end milling cutters for aerospace applications require tight tolerances and fine finishes.

Among Redzepagic’s top suggestions in the area of insert indexing and replacement: When there is a shim in the insert pocket, take a good look at it. And if the insert has left an impression in that shim, make sure to change the shim because the insert needs to lie on a flat surface. If it doesn’t, the insert will be able to move around in the pocket—and that motion can ruin both the insert and the cutter body.

To prevent this from happening, Dillaman added, users must know the torque capability of their machine and, if necessary, adjust their cutting operation to make sure the machine isn’t overloaded. Such adjustments could include reducing the feed rate or depth of cut.

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Taylor said that the new tool grinding machine has allowed his company to have greater versatility in its manufacturing.

At Greenleaf Corp., Saegertown, Pa., tool designers found that adding more pockets to their face-milling tools actually adds to the life of the inserts in the tools. What makes the difference is the extra inserts in those additional pockets. More inserts stabilize the cut and reduce the forces on each insert, which in turn reduces the number of times the inserts must be indexed, explained Martin Dillaman, Greenleaf’s applications engineering manager. “You may be adding some cost by adding an insert or two to the tool, but the productivity increases outweigh that,” he said.

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Due to the relatively high cost of carbide compared to steel, solid-carbide tools tend to be smaller than indexable tools. While the diameter of a common solid-carbide end mill might be ½" (12.7 mm) or ¾" (19 mm), Pollock said, indexable tools normally start at ¾" (19 mm), with 2" (50.8 mm) and 3" (76.2 mm) diameter sizes more common.

Whether or not shops choose to upgrade their indexable tool technology, they should never miss a chance to upgrade their insert indexing and changeout practices. Many tool manufacturers now offer customer instruction in this vital area—and it’s often badly needed, according to Sandvik’s Redzepagic.

Purchasing capital equipment can be a daunting task, but Taylor Toolworks, Calgary, found that with the right research and understanding of its business needs, the benefits offered by new technology can be a game-changer.

The machine generates 51 HP of peak spindle power, has linear scales on its X and Y axes, and includes a standard six-station wheel changer that stores and changes up to six wheel packs. In addition, the machine uses Anca’s LinX linear motors for X and Y axis motion, has an integrated wheel dresser, and is automated.

This is due to the price of steel and the relative ease of machining insert pockets into a steel body. “If you had a 10" (254-mm) diameter tool, you could easily put 10, 15 or even 18 carbide cutting edges in the steel body,” Pollock said.

With state-of-the-art 5-axis CNC grinding, combined with the use of good-quality micrograin carbide products, Taylor Toolworks maintains the highest tooling tolerances and creates mirror finishes needed for high-performance tooling.

What accounts for the popularity of indexable tools? Fundamentally, they are efficient tools for metal removal because of their structure, which typically consists of a number of carbide inserts installed in a steel body. This structure is very strong and capable of taking high-horsepower cuts, resulting in maximum material removal rates, according to Luke Pollock, product manager at toolmaker Walter USA LLC, Waukesha, Wis.

From a cost perspective, indexable tools require a significant upfront investment. According to Seco Tools’ Aydt, however, the investment cost can be paid back within a few months, depending on the application.

End mills produced at the shop have superpolished flutes, special-grade carbides, and special coating for maximum performance. Custom tooling also is made to a customer’s specifications for both the woodworking and metal industry. These include micrograin carbide inserts, custom-profile tools, and step drills.

Jesse Taylor, president of Taylor Toolworks, Calgary, stands in front of his company’s new Anca MX7 Linear tool grinding machine.

Nevertheless, some companies make tools with replaceable cutting edges that are aimed at what has traditionally been solid-carbide’s turf. For example, Iscar Metals Inc., Arlington, Texas, recently introduced indexable end mills with diameters that go to 5/16" (7.9 mm). The idea is to “complement solid-carbide tools, not totally replace them,” said Bryan Stusak, Iscar’s national milling product manager.

With a more uniform coating surface, cutting edges produce parts with better surface finishes, Dillaman noted. In addition, he said, coatings that lack thinner (and therefore more vulnerable) areas will do a better job of protecting insert substrates from heat.

The company’s small-diameter indexable milling cutters feature very small inserts. Stusak claims his company is the industry leader when it comes to five-axis pressing of inserts. “We have the ability to press and form inserts at very small diameters and hold tight tolerances,” he said.

While a solid-carbide tool is very hard and resists abrasive wear, “it is also on the brittle side so you are limited as to how hard you can push it,” Pollock said. With indexable tools, however, the toughness of the steel body comes into play. “You usually don’t think about an indexable milling body breaking, but solid-carbide tools break all the time,” he noted, adding that the steel body also makes indexable tools less susceptible to vibrations.

Being in the industry for more than 20 years, Taylor saw Anca machines at various tradeshows. When he was ready to make a machine purchase, he talked to several people at shows, including Anca application specialists. This made him take a closer look at the machines and he saw that they were suitable for his needs.

Sales figures don’t lie: indexable cutting tools—featuring removable cutting tips called inserts—are a smash hit with machine shops. According to a McKinsey & Co. report, indexable tools accounted for about 63 percent of U.S. milling tool sales in 2017, versus 26 percent for solid-carbide tools and 11 percent for solid non-carbide tools.

“One of the reasons we gravitated to Anca was the ability to automate our grinding wheel changes. We can utilize up to six different wheel packs without any manual intervention,” said Taylor. “We produce complex tools requiring many styles of grinding wheels for the same tool. This is something that is key to our success. The accuracy and high-speed movements of this machine have also helped us produce complex tools faster than previous generations of machines.”

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APCs make automation easy. Integrate in-machine, single-level, or tower options to automate your operations, store machined parts, reduce labor costs, and increase efficiency.

“The Anca linear motors provide a superior surface finish with an accurate and smooth movement for the part being ground. These linear motors are tubular in their design, which creates no friction or heat, compared to traditional flat linear motors. You also have the maintenance aspect of reliability and consistently accurate movement versus ball screws, which were used in the past by many machine tool builders, including Anca,” said Russell Riddiford, president of Anca Americas.

Dillaman added, however, that tool designers must be careful not to add so many insert pockets that there is no longer enough steel in the cutter to maintain adequate strength. In addition, users of tools with large numbers of inserts must make sure that their machines are up to the task of using all the cutters.

In addition to the coating itself, the method of applying the coating can have a major impact on inserts. “Today, coatings are being applied so that the peaks and valleys are much smaller when you look at the coatings under a microscope,” Greenleaf’s Dillaman said.

Another technological advancement extending the life of indexable tools is the modern electrostatic press. Andersson pointed out that these presses tend to be more precise than their older counterparts in insert production. “Any time you have smaller deviation from insert to insert, you reduce runout and get longer milling-tool life,” he said.

Besides the new MX7 Linear machine, the company has three other Anca machines, including the Fastgrind system for resharpening tools.

“This allows us to program tools [virtually] on a desktop before they are processed on the actual machine. This saves valuable machine time,” said Taylor.

“There are people in this industry who have developed really bad practices when indexing inserts,” she said. “I was surprised at how little education there’s been in that area, and how many shop owners still ask us to [provide] that type of education for their employees.”

With a chrome Duratomic coating, however, insert edges that have made any contact with a workpiece turn dark, making it easy to spot used edges. The idea is to reduce the number of insert edges that shops waste.

Redzepagic also advises shop personnel who remove inserts to make sure to clean the pockets, completely blowing out any chips that could scratch a surface and adversely affect insert fastening. If this isn’t done, the result, again, can be insert movement that wrecks the tool body.

“Grinding carbide these days is particularly challenging because of all the different grades being used for specific applications,” explained Taylor. “We grind many different carbide grades containing between 3 and 10 per cent cobalt content. Using our new Anca MX7 machine equipped with more than 50 HP and high-pressure coolant makes fluting operations much easier.”

Why do solid-carbide tools have an edge in these applications? Compared to indexable tools, “you’re going to be a lot more accurate with a solid-carbide round tool,” said Tim Aydt, indexable milling product manager at Seco Tools LLC, Troy, Mich. “Your wall finish will be better and your tolerance band will be a lot easier to maintain.” Indexables, he added, “are mainly just for metal removal and usually for larger machines making larger parts.”

Though not right for every cutting application, indexable tools have a number of inherent advantages over solid tools that account for their competitive edge in the tool market. In recent years, moreover, the competitive position of indexable tools has been strengthened by advancements that have increased tool life, improved cutting performance and sped up changeout.

“When you have multiple teeth in the cut, the forces required to spin the cutter go up significantly,” he said. “So you may run into instances where you will essentially stall the machine.”

Once on the job, indexables can last for longer periods of time than solid-carbide tooling. “You can keep using [an indexable tool] for three, five or even 10 years, depending upon what you’re using it for,” Aydt said. He added, however, that the carrier will always wear out eventually, with the pockets deforming over time because of the immense amount of heat and pressure applied to them.

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To understand how this works, consider an indexable tool with black inserts. An operator looking at the edges of one of these inserts may not be able to tell whether they have been used. As a result, the insert may be unnecessarily indexed or even replaced.

Recently the company purchased an Anca CNC MX7 Linear tool grinding machine because it met its demand of high-output, high-precision manufacturing.

The steel body of an indexable tool is used over and over while only the cutting edge is replaced. Normally, carbide inserts will have more than one cutting edge. When worn, the cutting edge is changed by turning or flipping the insert—i.e., indexing—to an unused cutting edge. According to Pollock, some tool designers focus on creating as many cutting edges as possible on one insert to improve the cost benefit of using their tools.

YG-1 Tool (USA) Co., Vernon Hills, Illinois, has introduced a similar product. “Traditionally, indexable milling had its lane that it stayed in and solid tools had their lane. You used indexable tooling for roughing and went with solid for more intricate details, tight tolerances or fine finishes,” said Jan Andersson, the company’s product management director for indexables.

Much larger sizes are also possible. “You couldn’t create a 10" (254-mm) diameter cutter out of solid carbide because it wouldn’t be economically feasible,” Pollock said. “But with a steel body, it is very easy and cost-effective to do.”

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Today, Andersson stated, “you have a little bit of overlap” between indexable and solid tools with diameters roughly in the range of ½" (12.7 mm) to ¾" (19 mm). A key development in this area is the appearance of what Andersson calls “semi-indexable” tools with a solid-carbide front end that threads into a steel or carbide carrier. With semi-indexable tools, he noted, “you still are getting the advantage of the indexable in that you are only replacing part of the tool, and you get more of the precision you get with solid tools.”

The company also uses Anca’s Tool Room software, which provides specific applications for each tool produced at Taylor Toolworks, such as a step tool editor or a profile tool editor.

Aydt often sees such waste firsthand. When he and his Seco colleagues walk into shops and look in their used carbide insert bucket, “many times we can tell they have thrown away unused edges,” he said. “Used-edge detection can prevent this from happening.”

Other developments have come in the area of coatings. One of these is Seco Tools’ latest Duratomic coatings, which feature what the company calls “used-edge detection.”

To extend the life of its indexable tool bodies, Sandvik Coromant prehardens the steel using a heat treatment process just before the pockets are machined. This makes it more difficult to damage the pockets when the tool is being used, according to Redzepagic.

According to Taylor, the tools produced on this machine include complex profile tools as well as step drills, through-coolant drills, and form tools. Applications for these tools are found in the aerospace, woodworking, general machining, and even plastics cutting.

The machine can handle varied batch sizes with minimal setup time and is suitable for high-volume production for tools up to 1 in. dia. The new cylindrical linear motor design increases reliability and ensures a superior surface finish.

Another toolmaker trying to move replaceable cutting edges into solid-carbide territory is Sandvik Coromant, Fair Lawn, N.J. The company offers an exchangeable head (EH) system consisting of a removable carbide cutting tip that typically screws into a steel body. In addition to reducing the amount and cost of carbide, the EH system speeds up and simplifies the process of exchanging cutting tips because it doesn’t require the removal of the entire tool from the machine, noted Anja Redzepagic, a Sandvik Coromant sales engineer.

“Offline simulation offers Anca users the ability to design a tool away from the machine (on a desktop PC), not consuming valuable machine time,” said Riddiford. “The ability to look at a finished tool without having made it on the machine and risk making a potentially scrapped piece or finding an incorrect program movement is key. You also can obtain cycle times from the simulation that can assist you in quoting a job.”

The company offers a reconditioning service, which involves tool regrinding, tool recutting, and tool recoating. It also has an in-house PVD-coating Centre.

Taylor Toolworks manufactures and services cutting tools for the North American metalworking and woodworking industries. It is the biggest part of its business. The company is run by President Jesse Taylor and his sister Kristyn Pixley, who has worked there for more than 15 years.

Like the EH system, YG-1’s product in this category, called iSmart, significantly reduces carbide-related tool costs and changeout time. On the downside, however, the presence of the threaded joint means semi-indexable tools are incapable of matching the precision of solid-carbide tools. As a result, Andersson places them in the semi-finishing category, between tools designed for roughing and those capable of superfinishing.

While indexable tools are the most popular choice for roughing, the situation is different for cutting applications that require smaller tool diameters or greater precision. In holemaking, for example, indexable tools have a much lower share of the U.S. cutting tool market, accounting for just 30 percent in 2017, according to McKinsey & Co., while solid-carbide tools accounted for 40 percent and solid non-carbide accounted for the remaining 30 percent.

An award-winning writer and graduate of the Sheridan College journalism program, he has published articles worldwide in a variety of industries, including manufacturing, pharmaceutical, medical, infrastructure, and entertainment.

While speed always seems to be emphasized and prized in manufacturing operations, Pollock maintains that it shouldn’t be shop personnel’s top priority when they are engaged in tool maintenance activities. “In this area, saving time isn’t necessarily the most important thing,” he said. “Doing a good and accurate job during the process is also important.”

“The pandemic definitely has confirmed the need to be a diverse manufacturer. We produce tools for all types of manufacturers, including aerospace, transportation, energy, wood, and plastic,” said Taylor. “When the pandemic first hit, we were called upon to make tooling required to produce life-saving ventilators. We were able to produce multifunctional profile tools that enabled part manufacturers to produce ventilators faster than ever before.”

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