“Also, lower vibrations lead to less pitting of the tool pocket, increasing toolholder life,” Garud continued. “The new patented design by Walter for our DX18 inserts securely clamps the inserts on three sides.” It also has “a secure prismatic base: a V-shaped top groove for the top clamping finger and a small double-faceted groove at the back of the insert to seat it securely in the insert pocket.”

“Jet cut tooling is vital today,” he said. “Iscar has taken great care in making sure coolant is introduced to the cutting edge of the insert even when high pressure is not accessible. Data has shown that in all cases this makes a difference in tool life and part quality.

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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.”

“The side-lock, or ‘smart lock’ as the technology is called, allows the users to index the inserts while the tool is still clamped onto the gang tooling of a Swiss machine,” he continued. “The side access to the indexing screws allows a time reduction of up to 70 percent in insert indexing, saving valuable time on high-volume Swiss machining operations.”

One question is what to expect in the next few years. “I believe one thing we will see is machines equipped with sensor monitoring technology watching slight changes in the tool and adjusting accordingly,” Kollenbroich said. “Some machine manufacturers already have things like this, but they are not accurate or sensitive enough yet. Incorporating this sensor technology into the toolholder and tying directly into the machine control is a possibility.”

Another example: “Heli Grip is a game changer due to its unique twisted geometry, enabling depths of cuts to go beyond the second edge of the insert without damaging it.” He said that results in “much deeper depths of cut—grooving and excellent groove turn capabilities.”

According to Garud, Walter is also adjusting design. “The need for higher volumes and reduced cycle times is always weighing down on tool manufacturers,” he said. “Walter recently introduced a new line of G4014 toolholders specifically designed for gang tooling. One of the key features of these holders is the side-access screw to clamp the insert into the toolholder.

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.

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.

Industry changes also create other considerations for toolmakers and their customers. “Geometry always plays a critical role in grooving operations,” Walter’s Garud said. “But parting-off operations typically tend to need the inserts to go all the way to the center of the bar, so cutting speeds are zero at the center, which means tougher grades are always going to be better than the harder grades. Also, chip-crimping is quite important. Not only do the chips need to curl into ‘sixes and nines’ shapes, they also need to be folded axially, so the chip breakers need to be aggressive to fold the chips.”

Added Vanderink of Iscar, “Technically, center-height position of the tool is critical. The process of a square tool plunging into a round part is very abusive. The centerline dynamic is not fiction. It is real and essential for success in these applications.”

“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.”

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.

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.

Iscar has had a series of product launches to address customer demands. “Cut Grip is one of the most complete and comprehensive grooving lines on the market,” Vanderink said. “Iscar promotes and champions the GTO (groove turn operation) as a cornerstone process for this line. Straight grooving and then turning side to side utilizing all edges of the insert reduces cycle time while producing excellent part finishes.”

“We are seeing the increased usage of Y-axis grooving and parting-off. By using this axis of the machine, we are able to increase cutting data, allowing our customers to reduce their cycle times,” he said. “Machine tool builders are adding features to their machines that allow for the use of the Y axis. Also, builders are looking at increasing the stroke of the Y axis, allowing for increased diameters where you can use Y-axis part-off tools.”

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.

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.

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.

At Horn USA, the company is offering coolant on more of its products. “This includes part-off and grooving holders and even some inserts,” Kollenbroich said. “Getting coolant to the cutting edge has many advantages. For one, having a more accurate delivery method for the coolant direction helps in cooling the work zone. It also offers the benefit of chip breaking when used with higher pressure applications.”

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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.

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.

“Multi-axis, multi-spindle machine tools with Y-axis capabilities are emerging to complete parts in one setup,” Vanderink continued. “The use of robots on the shop floor is increasing and is becoming a viable operation for small to medium-sized shops now.”

The company also looks to coating for product improvement. “We offer coatings that are capable of handling heat better, which in part-off and grooving is always a challenge,” he said.

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.

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.

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.

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.

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.

Added Steve Vanderink, national product specialist for grip products at Iscar USA, Arlington, Texas, “Users are demanding ease of indexing of the insert with accurate repeatability while increasing productivity with rigid support and strength in the pockets—all while keeping an eye on the economics. The market wants it all. Innovation is the driving force for solutions to the market’s needs.”

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.

Horn also offers a Y-axis part-off system. “This system uses the Y axis of certain lathes as feed direction,” Kollenbroich said. “This switch in axis feed directs forces back into the holder instead of against the holder. The improved strength allows for feed rate increases of two or three times that of standard X-axis part-off applications.”

“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.”

“As tool designers, we need to increase the pocket security of our grooving platforms to allow customers the freedom (to) turn in all directions,” said John Winter, turning specialist at Sandvik Coromant, Fair Lawn, N.J.

“Users are always demanding the same thing,” said John Kollenbroich, head of product management at Horn USA Inc., Franklin, Tenn. “More tool life and predictability, better chip control and surface finish. These demands have not changed in many years, nor will they change anytime soon.”

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.

Improvements in machine tools have also altered the way companies design tools. “The biggest improvement in machines that I have noticed is more machines are running high-pressure coolant,” Kollenbroich of Horn said. “Even the standard offering from most manufacturers is a considerable jump in pressure from what it was just a few years ago. High-pressure coolant offers benefits in chip breaking. Coolant-through tools, with better and more focused coolant delivery, remove chips from the work zone. This helps improve tool life and overall performance.”

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.

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.

Some trends in machining remain constant. Machine speeds continue to increase. Difficult-to-cut materials are used more frequently. The desire for better cooling, chip control and reliability remains.

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.

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.”

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.

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.

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.

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.

“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.

Higher machine speeds are also a big part of the demand on tools. “As the machines get more capable of higher speeds and torques, and the demand to get more out of the same tool constantly increases, manufacturers have to respond accordingly,” said Sarang Garud, product manager at Walter USA LLC, Waukesha, Wis.

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

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.

Sandvik Coromant works to make its products flexible. Winter said that with CoroCut 1-2 “you can part-off, groove, face groove and do high-feed machining of hardened steel. The CoroCut QD platform can part-off in both the X and Y axis and face groove.”

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.”

Walter USA has adjusted the way it clamps its inserts. “Usually the grooving inserts are held either through a self-clamping mechanism or through a ‘top-clamp’ screw-down mechanism,” Garud said. “The more secure the insert in the pocket, the lesser the tendency of vibration and longer the insert life.

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.

Progress in various manufacturing technologies may play a role in the future for parting and grooving, Iscar’s Vanderink said. “Additive manufacturing will be a big player from here on out,” he said. “Already, new concepts are on the way due to this technology. Additive manufacturing producing near-net shaped parts will change how removing material is viewed. This concept alone will drive the innovation needed to accommodate these types of components.”

Advancements in carbide substrates are “ever changing and we are seeing new grades and coatings that are making a meaningful impact in tool life,” he added. “Industry 4.0 is expanding into tooling more and more. Tracking of tool life and wear is becoming a seamless part of the manufacturing process.”

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.

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.

Kollenbroich of Horn noted that managing centerline is critical. “Centerline can be your biggest friend and your worst enemy. All manufacturers design their tools to work on center. When a machine is off, even slightly, things become unpredictable. Customers typically experience a drop in tool life, maybe poor surface finish or, worse yet, catastrophic failure. It is critical to apply part-off and grooving tools properly, and on center.”

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.

Said Winter of Sandvik Coromant, “We will see machines turning in all directions and the requirement for part-off and grooving tools is to do the same.”

“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.

He also said clamping is an issue. “Using torque wrenches when clamping inserts in all parting and grooving tools is essential to maintain clamping force, tool integrity and finally part quality.”

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.

“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.”

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

Kollenbroich described how Horn addressed that challenge with its 960 part-off system. “This is a cassette-based, coolant-through design that offers a major upgrade in blade stability,” he said. “This additional stability results in great improvement in tool life. Customers can realize gains of double or triple the tool life while showing dimensional improvements in flatness and surface finish.”

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.