Lisker said coolant-through technology is especially helpful when cutting nickel-base alloys like Inconel that transfer heat back to the tooling. Besides maintaining thermal stability on the cutting edge, he said coolant-through systems disperse chips to help with chip control.

When it comes to performance of indexable cutting tools compared with brazed PCD, CBN and carbide tip tooling, “it’s a question of cost and application,” Winter said. “Anytime you can use an indexable tool, the cost will be lower. The performance is in the cutting material (PCD, CBN, or carbide) and it’s a matter of if the tool can fit into the application.”

“If (the tool) is going on a lathe, our message is to use coolant-through tooling as a first choice,” said East, whose company offers tooling products of this type called Jet-Cut.

“We’re seeing a split in the market, a split where the indexables are being used for roughing and solid-carbide end mills do the finishing, especially as production components are becoming more near-net shape,” said Todd Miller, product marketing manager. “There is an equal need for indexables today as there is for solid tools.”

According to Ewing, Iscar now offers indexable head drills from 0.157 -1.575″ (4.0-40.0 mm) dia. Most of that range is offered in 0.004″ (0.10 mm) increments. Drill bodies are offered in 1.5xD, 3xD, 5xD, 8xD and 12xD drilling depths with some bodies offering chamfer collars for combined operations. In addition, standard tooling designs are also being incorporated into special tool applications to increase productivity in medium to large quantity part runs. The special tool is often more expensive than a standard tool, but because it utilizes standard indexable carbide inserts the consumable costs can be greatly reduced.

“New indexable cutting tools often require faster spindle speeds, increased feed rates and multi-axis capabilities that today’s modern CNC machines are capable of to maximize their performance,” said Ewing. “For example, a 0.157″ [4[4-mm]umoCham drill can run above 11,000 rpm and up to 40 ipm [1[1 m/min]n mild steel. Even at the low end, you need more than 6,000 rpm for this tool. Some machines from 10-15 years ago would not be able to properly run this tool.

WG-600, a coated whisker-reinforced ceramic, in particular is showing “outstanding performance in turning. Finally, applications where even large-grain carbide lacks toughness (heavy interruption, impurities, forging scale) can now be addressed with XSYTIN-1 where other ceramic and carbide tools break.”

“By pairing our patented Excelerator ball nose insert geometry with our WG-600 and XSYTIN-1 grades, we provide customers with the ability to mill hardened and difficult-to-machine materials with a full-radius ceramic indexable tool. Our Excelerator ball nose inserts with patented geometry offer better performance, longer tool life and superior cutting action across a wide variety of materials.”

Indexable tools can be used in almost every application. “We are seeing more use in high-speed aluminum machining,” he said. “Advances in insert geometry and grades, as well as balanced tools and rigid holding of the insert, allow indexable tools to be used at higher rpm and sfm. Aluminum machining can take advantage of high rpm and machine tool builders have been developing spindles to run at these speeds. Traditionally, solid tools would have to be used in these applications due to balance and rigidity.”

Indexable cutting tools are being used for innovative applications. “The biggest advancement for indexable tooling is in the application of those tools,” said Winter. “We are getting away from the ISO standard and pushing the limits of both tools and machines with creative designs. PrimeTurning is a perfect example of this. Using multi-directional turning, we see big gains in productivity and tool life. It used to be that ISO milling was the popular choice but now you would be hard pressed to find ISO milling in shops. By looking outside of ISO turning, we can push the tools, machines and the limits of the carbide inserts.”

Greenleaf’s latest advance and newest offering is the phase-toughened XSYTIN-1 ceramic which has “unprecedented edge strength, transverse rupture strength (the ability to support large forces, i.e. heavy chip flow), thermal shock resistance and toughness. XSYTIN-1 is also the most versatile ceramic in Greenleaf’s portfolio, successfully machining soft mild steel, weld-overlaid cobalt-based alloys and anything in between,” according to the Greenleaf team.

Seco Tools LLC, Troy, Mich., has developed advanced coatings such as a Niobium PVD thin coating for machining titanium and plans further advances in its Duratomic aluminum oxide-based CVD coating for general types of steel and cast-iron machining.

Turning machine capable of sawing, milling, grinding, gear-cutting, drilling, reaming, boring, threading, facing, chamfering, grooving, knurling, spinning, parting, necking, taper-cutting, and cam- and eccentric-cutting, as well as step- and straight-turning. Comes in a variety of forms, ranging from manual to semiautomatic to fully automatic, with major types being engine lathes, turning and contouring lathes, turret lathes and numerical-control lathes. The engine lathe consists of a headstock and spindle, tailstock, bed, carriage (complete with apron) and cross slides. Features include gear- (speed) and feed-selector levers, toolpost, compound rest, lead screw and reversing lead screw, threading dial and rapid-traverse lever. Special lathe types include through-the-spindle, camshaft and crankshaft, brake drum and rotor, spinning and gun-barrel machines. Toolroom and bench lathes are used for precision work; the former for tool-and-die work and similar tasks, the latter for small workpieces (instruments, watches), normally without a power feed. Models are typically designated according to their “swing,” or the largest-diameter workpiece that can be rotated; bed length, or the distance between centers; and horsepower generated. See turning machine.

Coolant Ring Technology holders allow better coolant penetration into a bore during cutting operations. Image courtesy of Scientific Cutting Tools

William Leventon is a contributing editor to Cutting Tool Engineering magazine. Contact him by phone at 609-920-3335 or via email at wleventon@gmail.com.

There is still room to maximize ceramic indexable tooling. “Unless we are running on state-of-the-art, purpose-built, latest generation machines, we are limited by the rigidity, dynamics or power when applying ceramic indexable tools. In an ideal environment we are able to turn Inconel 718 at 1,476 sfm (450 m/min) with WG-300, or at 820 sfm (250 m/min) with XSYTIN-1, but with a very heavy chip,” according to the team.

Chip problems like these can be prevented by improved coolant delivery, which is possible today thanks to several developments. One is the increased coolant pressures produced by current machines. White said these pressures typically range from 300 psi all the way up to 1,000 psi.

“When customers come to us for grooving tools, it is usually for a turnkey operation” — that is, a job for which Mikron produces most if not all of the different tools needed to make a part, said Sales Manager Nathan Lisker.

If the chipbreaker doesn’t, Coomer said, “the chips will get stuck, especially once you get down into the groove a little bit. This will cause some marring of the parts.”

Another material that has not been an application area for ceramic indexable tooling is stainless steel. Duplex, 300 series and precipitation hardening steels are now being machined effectively with Greenleaf’s whisker-reinforced ceramics, according to the company.

If the tool isn’t, “the edge of your tool is going to be tilted, so you could potentially be running scrap parts,” said Clay East, national product manager for grip systems at Iscar Metals Inc. in Arlington, Texas.

A single insert also can be used to combine grooving and turning processes. This wasn’t the case back when East worked at a machine shop.

Pollock said that there are some machines and applica-tions where the machines can push the capability of the tools in aluminum machining. “But I think the more common point is that modern cutting tools allow machines to do more. Carbide substrates and free-cutting geometry increase the capability of smaller machines to process a wider variety of materials and large parts,” he said.

For deep-hole applications, Iscar offers a line of BTA drills in single-tube and double-tube variations; indexable gun-drills including the Sumo-Gun and Tri-Deep; and standard gundrills. Indexable reaming tools include the Bayo-T-Ream, Index-H-Ream, and Solid-H-Ream.

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If chamfers are on the top of the grooves, Coomer said the insert can be modified to create those features as well, “so you can cut all four grooves and put chamfers on them in one shot.”

“In turning, everybody has the same ISO standard toolholders so it’s technology like our Steadyline anti-vibration holders, Jet Stream tooling holders and second generation Duratomic coating that makes a big difference,” said Miller. “In milling, there have been many technological advancements as well as process improvements. Today, processes like dynamic milling require high-tech tools that take a full axial DOC and a light radial DOC at an extremely high feed rate.”

For deep-hole applications (>8xD), Iscar has also added double-margin drilling heads as well as inserts designed with self-centering, chip-splitting and flat-bottom geometries. In the DR-Twist line (four cutting edge inserts), there are geometries for general applications (medium to high feeds), soft materials (low to medium feeds) long-chipping materials (added chipbreakers) and aluminum (ground sharp edge, polished face).

Improvements in indexable cutting tools extend to virtually every cutting process. Until the day when it will be sufficient to establish a baseline for comparative and competitive tooling performance through data analytics (a distinct future possibility of digitization and the IIoT), cutting tool manufacturers will rely on tried-and-true processes.

In some instances, he said, “a coated tool is only a few dollars more than an uncoated one. But in the right materials, it can give you three to five times the tool life of an uncoated tool. So you get a great return for a small investment in the tool.”

Shops can get off to a good start with grooving by making sure the tool in the lathe turret is perpendicular to the workpiece surface.

Positive cutting geometry can maintain acceptable, if not increased, tool life and allows for lower horsepower cuts and less torque on the machines, according to Pollock. However, this can create a weak cutting edge.

“If you can’t get the chips out of the bore,” White said, “usually you will re-cut them, and then they will scar the surface.”

Winter said that the latest developments for indexable milling, turning and drilling tools are more application-specific tools designed to perform a set operation at the highest level of performance. The processes will be optimized to maximize the machine tool, workholding and the tooling for a set application or component.

Many part designs include a chamfer at the top of the groove to eliminate burrs. In these cases, shops can opt for grooving inserts that incorporate chamfering, said Coomer, whose company makes such inserts. By cutting the groove and chamfer at the same time, users eliminate a secondary operation to create the chamfer when the groove is finished.

“We are integrating the same positive cutting action and effective cutting rake angles of our single-sided insert cutters into our double-sided insert cutters. Incorporating the geometry of the single-side, four-edge square type insert into double-sided inserts allows you to get free cutting action and economy,” he said.

East said groove/turn operations used to require two things. One was that CAD/CAM companies had to be pressed to create code for the work. Also, he said a special type of insert was needed, one with a chipformer on the front for plunging, plus a chipformer on each side for turning.

If the groove to be cut isn’t too deep, he believes that Top Notch-style inserts may be a good choice. These feature molded notches on the top and bottom that seat the inserts in their holders. With the inserts held at a 3-degree angle, the notches pull them back into the pocket during cutting, he explained, making the system very rigid and stable.

They will mix and match data about chemical makeup, substrates, geometry and machine capability to advance technology the old-fashioned way—by R&D expertise, trial and error, internal testing and validation of new concepts in the field. Here’s how major cutting tool manufacturers are advancing the technology of indexable cutting tools.

For drilling, along with the SumoCham and DR-Twist lines, Iscar offers the LogIQ-3-Cham, Cham-IQ Drill, Combi-Cham and Modu-Drill, as well as solid-carbide drills. The LogIQ-3-Cham three-flute drill offers higher feed rates due to the extra flute and creates more accurate holes in terms of diameter tolerance and roundness. The Modu-Drill series [1.299-1.575" (33-40 mm)] has interchangeable heads for different sizes and styles (Cham-IQ Drill, Combi-Cham and DR-DH).

Improvement in indexable tooling requires a holistic approach, according to John Winter, product management-East U.S. for toolmaker Sandvik Coromant, Fair Lawn, N.J. “We are pushing every aspect of the process to produce the best cutting tool solution possible, from coating technology to the macro and micro geometries that produce a stronger edge line to the post-treatment processes that give the coatings a harder, smoother surface.”

Brazed tooling is generally considered to have tighter tolerances since the assembled tool can be finished (ground and polished). These harder materials in brazed form are usually limited in the cutting geometry that can be used in the tool design. Indexable inserts have the opportunity of geometry pressed into the insert so that different machining applications can be handled simply by using a different insert with different geometry or grade.

“Current insert substrates and pressing technology allow for free-cutting positive geometry that doesn’t easily chip,” he said. “Positive geometry can even be added to inserts with negative basic shape or even tangentially mounted inserts.”

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“These features have contributed to increases in operating parameters and tool life and resulted in innovations in indexable tools for holemaking,” said Craig Ewing, national product specialist-drilling for Iscar.

“Even if the groove was wider than it was deep,” he said, “if it had 90-degree corners, you would take a groove tool and plunge all of that material out. Today, we want to apply a groove/turn solution in these cases.”

High speeds or high cutting forces amplify even the smallest instabilities in a machine, leading to deflection and, since the process is inherently cyclic, vibration. No matter how tough a ceramic is, vibration leads to irregular mechanical loads that bring about irregular wear that then translates into poor tool life.

Grooving also goes better these days thanks to advances in tool coatings. The latest coating materials are heat- and wear-resistant, which increases tool life. White said they additionally improve speeds and feeds by preventing workpiece materials from sticking to tools.

Workpiece is held in a chuck, mounted on a face plate or secured between centers and rotated while a cutting tool, normally a single-point tool, is fed into it along its periphery or across its end or face. Takes the form of straight turning (cutting along the periphery of the workpiece); taper turning (creating a taper); step turning (turning different-size diameters on the same work); chamfering (beveling an edge or shoulder); facing (cutting on an end); turning threads (usually external but can be internal); roughing (high-volume metal removal); and finishing (final light cuts). Performed on lathes, turning centers, chucking machines, automatic screw machines and similar machines.

“Time is money. By pushing the machines and the machines pushing the tooling, we can meet the needs of our customers and help save time and be more profitable,” Winter explained.

He advises those who use inserts to cut grooves to make sure the chipbreaker folds the chip in a way that makes it smaller than the groove being cut.

Cutting tool improvements range from some actual grades that are being refined with additives in the substrate for better wet or dry machining to product upgrades. Improvements to Seco’s Perfomax indexable insert drill, for example, include an improved, highly polished body with wave pattern technology for chip evacuation, increased hardness for wear resistance and elimination of coating altogether.

When indexable tools are used for grooving, “many times your chipbreaker is a big key to success,” said Travis Coomer, national key account manager at GWS Tool Group in Tavares, Florida.

Machining operation in which material is removed from the workpiece by a powered abrasive wheel, stone, belt, paste, sheet, compound, slurry, etc. Takes various forms: surface grinding (creates flat and/or squared surfaces); cylindrical grinding (for external cylindrical and tapered shapes, fillets, undercuts, etc.); centerless grinding; chamfering; thread and form grinding; tool and cutter grinding; offhand grinding; lapping and polishing (grinding with extremely fine grits to create ultrasmooth surfaces); honing; and disc grinding.

Maximizing indexable cutting tool performance depends on whether or not operators are pushing their machines to their fullest potential for both tooling and process. “We need to educate our customers on best practices to be more aware of their machine utilization,” he said. “Many shop owners or plant managers can only give you an educated guess of their actual machine utilization and that utilization is sometimes much lower than they think. And on-lights, stopwatches and clipboards are being replaced by machines and tooling with sensors that can give thousands of data points.”

“Today’s mill-turn machine offerings make it easy to combine many operations into one setup that often had to be done in multiple setups in the past. Iscar offers indexable tooling solutions that take advantage of these machine capabilities, such as multi-function tools for turning, facing and threading operations.”

When customers ask why they should pay more for Jet-Cut holders, he points out that coolant pinpointed on the cutting edge increases tool life, which translates into more parts per edge. He notes as well that efficiently delivered coolant quenches chips and makes them brittle, so they break up more easily.

Whisker-reinforced ceramics have sufficient hardness (and more than sufficient toughness) to machine most of the materials where carbide tools lack hardness and CBN lacks toughness. In addition, the tooling costs associated with indexable ceramics are significantly lower per cutting edge than they are for CBN.

Groove or other tool geometry that breaks chips into small fragments as they come off the workpiece. Designed to prevent chips from becoming so long that they are difficult to control, catch in turning parts and cause safety problems.

Winter pointed to Sandvik Coromant’s CoroPlus digital machining system as an example. “With the use of CoroPlus, you can use machine analytics to see exactly where you can make improvements to maximize your production. CoroPlus is data-driven process control that will push the tools and machines to the highest level of productivity possible with modern tooling,” he said.

When a groove is very wide, White warns that cutting it all at one time can put too much pressure on the tool, causing deflection problems and even breakage. So in cases like this, he believes that a better approach can be to employ a peck cycle — in other words, making a couple of passes to depth using a tool that’s thinner than the groove, then moving the tool over a little and doing the same again. Besides going easier on the tool, he said a peck cycle gives a chance to flush out potentially problematic chips.

Another timesaving option he recommends is using a multigroove tool to cut multiple grooves right next to each other. To simultaneously cut four adjacent grooves, for example, shops can use an insert with four adjacent cutting edges.

For deep grooving applications, the company typically produces solid-carbide tools because of their superior rigidity. White pointed out that the allowable length-to-diameter ratio for carbide tools is 10-1 compared with 3-1 for indexable toolholders made of steel.

Substances having metallic properties and being composed of two or more chemical elements of which at least one is a metal.

Among the coatings that Scientific Cutting Tools uses for grooving tools are diamondlike carbon coatings, such as ta-C, which he describes as a very hard, thin coating that works well on tools used to cut abrasive nonferrous materials.

“To be fair, there are other uncertainties that could be contributing to instability—lack of rigidity and vibration dampening in the fixture, for example,” according to the team. “Comparatively few machines are also equipped with high-pressure coolant, which is extremely beneficial in the rough- and medium-turning of heat-resistant superalloys in that it greatly improves chip management (and to some extent also improves the dissipation of heat from the tool).”

Common grooving options today include solid-carbide tools and indexables. When it comes to grooving, the focus at Scientific Cutting Tools Inc. in Simi Valley, California, is mainly on grinding solid-carbide tools for cutting internal grooves for things like threads and O-rings, said Sales Director Todd White.

Another is the variety of coolant-through tooling options available. As the name suggests, this type of tooling features internal passages for coolant flow. White said many different toolholders feature coolant-through designs that get coolant right to the cutting edge to lessen thermal degradation of the substrate.

Substance used for grinding, honing, lapping, superfinishing and polishing. Examples include garnet, emery, corundum, silicon carbide, cubic boron nitride and diamond in various grit sizes.

“Indexable tooling exists for almost every type of application: milling, turning and grooving, drilling, slotting, boring, and reaming,” explained Luke Pollock, product manager, Walter USA LLC, Waukesha, Wis. “They all use different styles of inserts designed for the needs of the applications. Typically, indexable tooling is considered larger and therefore stronger, capable of taking higher horsepower cuts and higher material removal rates compared to solid tooling. As a result, indexable tools have become more competitive in applications traditionally dominated by round tools.”

No one can accuse cutting tool manufacturers of not trying every possible combination of coating, substrate, material and geometry in their quest to gain a competitive edge for their customers.

Within its milling family of products, Seco Tools is launching a double-sided face mill called the Double Quattromill 14, building on the success of its Double Quattromill 22 face mill for roughing and semi-finishing introduced at IMTS 2018 for heavy DOC machining.

He recommends running an indicator along the length of the tool to check perpendicularity. For a 102 mm (4") tool length, the measurement should be off by no more than about 0.1 mm (0.004"), he said.

“These can be challenging if they are at the bottom of a small-diameter hole,” he said. “You’ve got to have the proper reach to get to the groove (location) and then be able to machine it successfully.”

Fluid that reduces temperature buildup at the tool/workpiece interface during machining. Normally takes the form of a liquid such as soluble or chemical mixtures (semisynthetic, synthetic) but can be pressurized air or other gas. Because of water’s ability to absorb great quantities of heat, it is widely used as a coolant and vehicle for various cutting compounds, with the water-to-compound ratio varying with the machining task. See cutting fluid; semisynthetic cutting fluid; soluble-oil cutting fluid; synthetic cutting fluid.

When a grooving operation is required, don’t plunge in without giving careful thought to what you’ll be using and how to go about the task. Specific items that should be considered include proper preparation, tool and process options and what the latest technology has to offer. Time spent upfront on these important topics can pay off in longer tool life, faster cycle times and better grooving results.

In recent years, Iscar Metals Inc., Arlington, Texas, has made performance improvements by adjusting the alloying elements in tungsten carbide substrates, using new combinations of various coating layers and applying post-coating treatments. Iscar has also developed different edge prep geometries for a variety of material group applications.

Provided with a part drawing or the part itself, Mikron will grind a tool designed for the special form or profile to be grooved into the part.

Greenleaf Corp., Saegertown, Pa., is continually working to develop improvements in geometries to match the capabilities of its ceramic and carbide grades. The following is based on a written assessment of product and technology advances provided by the Greenleaf Applications Engineering Team.

One example is boring a large bore where an indexable boring bar will fit vs. using a small bore where only a brazed tipped bar can fit. The same is true of milling and drilling. “Here you can find advancements with PCD-veined tools versus brazed tools where the PCD is pressed into the tool not brazed,” he said. “This allows us to shape the PCD to the mill or drill tip, giving these tools better performance.”

Machining grooves and shallow channels. Example: grooving ball-bearing raceways. Typically performed by tools that are capable of light cuts at high feed rates. Imparts high-quality finish.

Iscar continues to expand the line of drilling tools with new cutting geometries. In the Sumo-Cham line there are different edge preps for steel (P), stainless steel (M), cast iron (K) and non-ferrous (N) materials.

East said one reason to opt for a groove/turn operation is that chip control is easier when turning than when plunging. In addition, he said groove/turn processes reduce cycle time because metal removal rates are usually “a lot better” than those achieved with plunging.