Tooling manufacturers continually experiment with new mixes of standard coating materials and introduce new elements.

A top layer of coating such as a colourful chrome that wears away to expose the different colour of the layer below can, by itself, provide a significant increase in productivity.

Insert manufacturers, like electronic providers that continually upgrade cell phones and televisions, continually invest in research and development to make their cutting tools do a better job. The upside to not staying with the coating developed a few years ago is that new, more effective coatings add more to the bottom line. The downside, which isn’t really a downside, is that there are many more options to choose from which can make selecting the right cutting tool a bit difficult. Experts at each tooling company save the expanded options from being a problem. They will collect information on the process being used, the material being cut, and the end product being produced to be sure the right coating is selected to provide quality cuts and long-lasting performance.

Iscar’s DO-TECH coating combines the CVD and PVD technologies to create a coating that improves performance when cutting cast iron for milling and turning. Geisel said, “We use a lot of titanium carbides and aluminum oxides. We also use titanium nitride—it’s a good coating to use as a top layer because it’s gold and shows the wear.”

Copher said the ability of tooling manufacturers to control the crystal orientation keeps the coatings in line with each other. “Controlling the crystal orientation helps the wear resistance, the peeling resistance, and the breakdown of the coating during the machining process.”

Iscar’s grade IC6025 structure is for turning ISO M materials. Each layer of the coating and its thickness are chosen to meet a specific need. Photo courtesy of Iscar.

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In parting, the rigidity of insert clamping is a key factor. The desire to achieve sensible and economical use of workpiece material dictates the ultimate reduction in cutting width. An increase in the diameter of the workpiece leads to the increase of the tool’s overhang. The narrow width of the insert and the blade can degrade the tool’s dynamic behaviour and ultimately affects machining performance. Improving clamping rigidity and increasing the tool strength to assure effective cutting under unfavourable cutting conditions are key factors when designing a parting tool.

John Copher, applications engineer at Sumitomo Electric Carbide Inc., said, “Part of my job is answering the engineering hotline, and almost every day someone calls and says they are working with a material we have never heard of before. As a tooling provider, we have to find out what is in the material and work with the caller to assign the grade and coating that will work best. All the old materials are still out there, but there are a lot of new materials in the aerospace, automotive, and medical fields that have caused us to adjust the technology that produces the coatings on the inserts that will cut those materials.”

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Sue Roberts, associate editor, contributes to both Canadian Metalworking and Canadian Fabricating & Welding. A metalworking industry veteran, she has contributed to marketing communications efforts and written B2B articles for the metal forming and fabricating, agriculture, food, financial, and regional tourism industries.

Pinpointed high pressure coolant (HPC) provides competitive advantages for better parting performance by decreasing temperatures at the cutting zone and by assuring excellent chip breaking, which substantially improves surface finish and prolongs tool life. In machining difficult-to-cut heat-resistant superalloys and austenitic stainless steel, HPC reduces or even eliminates the built-up edge phenomenon. High-pressure coolant is highly advantageous in parting operations.

“We did a spot check with some of our customers. We would go to a recycle bin, grab a handful of inserts, and check the edges. They were shocked at the number of unused edges that were thrown into the bin,” said Eller. “Simply having used edges visually apparent in contrast to unused edges made it easy for operators to use all edges before tossing an insert. It creates a substantial cost savings.”

Steve Geisel, senior product manager at Iscar Canada, said that there are three main categories of coatings: chemical vapour deposition (CVD), physical vapour deposition (PVD), and uncoated. CVD coatings are generally thicker and allow machining at higher surface footage, which can be good for machining carbon and alloy steels. PVD coatings are for the high-temperature alloy materials because the coatings are very thin to allow the insert to absorb heat. That quality avoids work hardening that would be caused by heat reflecting back into the cut or chip. Uncoated inserts are used for high temperature applications like titanium because many of the coatings have a titanium layer and the cutting tool needs to be harder than the material being cut.

Sumitomo’s CVD Absotech™ Platinum coating is a multilayer aluminum oxide/titanium carbon nitride designed mainly to cut carbon steels, tool steels, and stainless steel. Copher said that the Absotech Bronze PVD coating of titanium aluminum silicon nitride is recommended for interrupted machining of stainless steel and exotic materials.

Structure of the atoms within the coatings and how each coating adheres to the layer above and below also plays a large role in their effectiveness.

Uncoated inserts, along with the CVD and PVD coated inserts, benefit from new substrates. For coated inserts, new chemical formulas continue to make them last longer, be more efficient, and have the ability to cut established and new materials faster.

Each layer of a nanolaminate PVD coating is approximately 7 nm thick. Varying the individual layer materials and thicknesses makes it possible to adjust the hardness and thermal stability properties. Photo courtesy of Seco Tools LLC.

The Self-Grip tool proved to be a game changer in parting. Shortly after its inauguration, similar designs by other producers appeared in the metal cutting market. Iscar had already established its name as the authority in parting applications and quickly became the unrivaled leader in the industry. Today, there is no question why Iscar’s ongoing inventions of new parting tools attract great interest and deserve such close attention.

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The Self-Grip clamping concept utilised the elastic behaviour of a parting blade. This attribute paved the road for a new and improved parting system which took clamping stiffness to a new level. Tang-Grip functions on the principle of supreme support for the insert to counteract cutting forces applied on the tool during the operation. (Fig. 4). The orientation of the slot that functions as an insert pocket was changed compared to the Self-Grip tool design, and therefore support is achieved by the long and rigid rear wall of the pocket. Tang-Grip has a solid stopper, unlike the friction retaining force that characterises most parting systems that feature a self-clamping insert. This mechanical design feature eliminates insert pull out during retraction. Significantly improved rigidity results in noticeably increased tool and pocket life. Together, with a robust insert design and a reinforced cutting edge, Tang-Grip enables parting at exceptionally high feed rates, consequently increasing productivity to new extremes.

“I’ll ask manufacturers why they are using a particular insert or coating and they say, ‘It’s just what we had.’ That’s understandable if they have only a few pieces to make, but they need to understand that all tooling manufacturers are improving technologies,” Geisel said. “A grade of coating they used 10 years ago is completely different from today’s grades which are much better.”

“We are starting to use coatings that incorporate rare-earth elements to try to get the coating at a higher hardness than the material being machined,” said Geisel.

When searching for the right parting tool, all manufacturers stand at the parting of the ways. Iscar’s milestones in creating revolutionary parting systems prove once again its commitment to advanced solutions to meet customer demands.

Understandably, many of the new coatings have been developed to increase production in exotic and difficult-to-machine materials, but not all. Some new coatings boost production for established, more common materials.

Every shop’s desire is to increase production without losing quality amidst faster machining processes. Lean manufacturing remains a common goal. Lights-out production requires inserts that last until an operator returns to change edges. A job shop gets a job that requires working with a new, difficult material. Chances are the best insert and coating to be used is not an old reliable. These are the types of situations that drive coating research forward.

Easily access valuable industry resources now with full access to the digital edition of Canadian Metalworking.

The Pentacut family of tools that mount star-shaped carbide inserts were originally designed for parting small-in-diameter workpieces, tubes, and thin-wall parts. These cost-efficient inserts provide five indexable cutting edges and a highly economical utilisation of tungsten carbide. The inserts are clamped in the insert pocket by a screw that passes through the insert’s central hole. The evolutionary stages of the five cornered insert proved to be difficult when utilising Pentacut inserts for large diameter workpieces. To successfully contend with this task, the insert needed to grow in size which made the task technically problematic and economically impractical.

“Whenever we’re working with a manufacturer, we have them show us the machine to be used, specify the material, and show us the workpiece. The workpiece itself is key. Is it an easy shape or some sort of irregular shape that needs counterweights because the part might not run perfectly true? A prime example is the automotive industry because its parts might have lobes or protrusions so they have to be offset when they run. That affects the insert wear. We get a feeling for what type of cutting parameters they can operate safely and then determine the insert and coating. If you run too fast, you can risk throwing a part out of a machine and hurting the operator,” said Geisel.

Notwithstanding, there appears to be another side of the ‘parting’ coin. Increasing the feed rate causes an increase of cutting force components. The situation worsens when the diameter of a bar and depth of penetration become larger. This results in blade deflection, which can become a significant factor in affecting the application. The method of utilising Y-axis parting is a way to overcome the problem. The blade is loaded in a manner which is preferable. Y-axis parting is common on multitasking machines with a Y-axis drive assuring appropriate feed motion, yet these machine types are not popular.

The solution was found in the Penta-IQ-Grip, a family of parting tools that also mounts indexable inserts with five cutting edges. The family enables parting workpieces in diameters of up to 40mm. Due to an innovative dovetail securing principle, the tools utilise relatively small-sized inserts and provide highly rigid clamping which significantly increases tool life, improved part straightness and surface finish in parting applications. In addition, there are Penta-IQ-Grip tools with an HPC option (Fig. 3).

Most of the coatings, nearly 90 per cent according to tooling manufacturers, are multilayer. The elements making up each layer, the thickness of each layer, and the order in which they are applied to the insert dictate what materials they can cut and how long they will last.

Duratomic® from Seco is a CVD aluminum-oxide coating for increased edge toughness, more wear resistance, and smooth surface finishes that are cut with less friction, said Eller. When the insert does begin to wear, the chrome included in its makeup shows the worn edges.

“In CVD aluminum-oxide coatings, the atoms are arranged in a hexagonal form. In the past the orientation of the coating’s building blocks were randomly arranged. Today we can control the orientation and bring a harder and tougher structure to the point of the cut. These textured coatings are 15 per cent tougher and 10 per cent harder than the old version. That means as much as 20 per cent more cutting speed or 30 per cent more tool life.”

Iscar’s Self-Grip tool concept was a breakthrough, which aspires its prolific R&D engineers to continue improving the concept today. The “classical” Self-Grip tool line has been upgraded and considerably expanded with new geometries and remarkable approaches to parting metal productively. The evolution of Iscar’s parting tools exemplifies a logical progression of development by use of highly engineered solutions throughout several generations of R&D engineers.

The production of effective inner coolant channels in thin tool blades is a difficult engineering task. Iscar has provided robust solutions to contend with this problem. One of these solutions is offered through Do-Grip parting tools, developed several years after the successful launch of the Self-Grip tool line. A Do-Grip tool carries an insert with two cutting edges situated at opposite ends. The edges are twisted relative to each other. Thus, the non-working edge does not limit the cutting depth of the tool. (Fig. 2).

A Do-Grip parting blade with inner high pressure coolant channels (from NPA 49-2015, “808” on the insert should be re-oriented)

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Coatings like Sumitomo’s CVD Absotech Platinum are designed to increase cutting speeds and improve cuts in carbon steels, tool steels, and stainless steels. Photo courtesy of Sumitomo Electric Carbide Inc.

Easily access valuable industry resources now with full access to the digital edition of Canadian Fabricating & Welding.

Back in the seventies, Iscar introduced Self-Grip, the brand name of the original blockbuster parting tool design concept. According to the design concept of the Self-Grip tool (Fig. 1), a pressed carbide insert was clamped into a tool blade using the blade’s elastic forces without the need for mechanical securing elements. At that time, other manufacturers also attempted to clamp inserts into a parting tool using the same principle. However, it was Iscar that invented a reliable, truly workable concept that set the benchmark for parting applications.

A Penta-Iq-Grip tool with dovetail clamping mechanism provides high pressure coolant supply in two directions (NPA 47-2016)

Aaron-Michael B. Eller, product manager—ISO turning and advanced materials, Seco Tools LLC, said, “In PVD aluminum titanium nitride or titanium nitride coatings, the atoms are arranged in a cubic form. During use, structural and compositional changes take place. Some are helpful but others are not. By controlling the coating process, we can encourage the good and deter the bad, resulting in increased speed capability and wear resistance.

Compared to traditional parting along the X-axis, Y-axis parting substantially improves the blade’s dynamic behaviour by use of a tangential cutting force. When parting in the direction of radial forces, blade rigidity is reduced. Once again Iscar’s prolific R&D engineers invented a formidable winning solution by introducing Logiq-F-Grip, a new tool family characterised by a square adapter with four inserts mounted on each of its cutting tips. (Fig. 5). The adapter combines both blade orientations (in X and Y-directions) which provides a balanced-rigid design. The adapter has four insert pockets, and substantially prolongs tool life. If one of the pockets is damaged, the adapter can be indexed in a simple manner. The adapter is available with or without an internal HPC option and mounted in a robust block with reinforced ribs that assure a highly durable parting tool assembly. The impressive rigidity of the system results in highly stable efficient parting at narrow widths of cut, even when used for parting large-in-diameter bars while guaranteeing savings in raw material. The system is suitable for all types of lathes, regardless of whether they have a Y-axis drive.

Follow that path only if you want to lose productivity today.Insert manufacturers, like electronic providers that continually upgrade cell phones and televisions, continually invest in research and development to make their cutting tools do a better job. The upside to not staying with the coating developed a few years ago is that new, more effective coatings add more to the bottom line. The downside, which isn’t really a downside, is that there are many more options to choose from which can make selecting the right cutting tool a bit difficult. Experts at each tooling company save the expanded options from being a problem. They will collect information on the process being used, the material being cut, and the end product being produced to be sure the right coating is selected to provide quality cuts and long-lasting performance.Every shop’s desire is to increase production without losing quality amidst faster machining processes. Lean manufacturing remains a common goal. Lights-out production requires inserts that last until an operator returns to change edges. A job shop gets a job that requires working with a new, difficult material. Chances are the best insert and coating to be used is not an old reliable. These are the types of situations that drive coating research forward.John Copher, applications engineer at Sumitomo Electric Carbide Inc., said, “Part of my job is answering the engineering hotline, and almost every day someone calls and says they are working with a material we have never heard of before. As a tooling provider, we have to find out what is in the material and work with the caller to assign the grade and coating that will work best. All the old materials are still out there, but there are a lot of new materials in the aerospace, automotive, and medical fields that have caused us to adjust the technology that produces the coatings on the inserts that will cut those materials.”3 Main TypesSteve Geisel, senior product manager at Iscar Canada, said that there are three main categories of coatings: chemical vapour deposition (CVD), physical vapour deposition (PVD), and uncoated. CVD coatings are generally thicker and allow machining at higher surface footage, which can be good for machining carbon and alloy steels. PVD coatings are for the high-temperature alloy materials because the coatings are very thin to allow the insert to absorb heat. That quality avoids work hardening that would be caused by heat reflecting back into the cut or chip. Uncoated inserts are used for high temperature applications like titanium because many of the coatings have a titanium layer and the cutting tool needs to be harder than the material being cut.Advances are continually being made in all three categories.Uncoated inserts, along with the CVD and PVD coated inserts, benefit from new substrates. For coated inserts, new chemical formulas continue to make them last longer, be more efficient, and have the ability to cut established and new materials faster.Most of the coatings, nearly 90 per cent according to tooling manufacturers, are multilayer. The elements making up each layer, the thickness of each layer, and the order in which they are applied to the insert dictate what materials they can cut and how long they will last.Tooling manufacturers continually experiment with new mixes of standard coating materials and introduce new elements.“We are starting to use coatings that incorporate rare-earth elements to try to get the coating at a higher hardness than the material being machined,” said Geisel. Iscar’s grade IC6025 structure is for turning ISO M materials. Each layer of the coating and its thickness are chosen to meet a specific need. Photo courtesy of Iscar.The Shape of AtomsStructure of the atoms within the coatings and how each coating adheres to the layer above and below also plays a large role in their effectiveness.Aaron-Michael B. Eller, product manager—ISO turning and advanced materials, Seco Tools LLC, said, “In PVD aluminum titanium nitride or titanium nitride coatings, the atoms are arranged in a cubic form. During use, structural and compositional changes take place. Some are helpful but others are not. By controlling the coating process, we can encourage the good and deter the bad, resulting in increased speed capability and wear resistance.“In CVD aluminum-oxide coatings, the atoms are arranged in a hexagonal form. In the past the orientation of the coating’s building blocks were randomly arranged. Today we can control the orientation and bring a harder and tougher structure to the point of the cut. These textured coatings are 15 per cent tougher and 10 per cent harder than the old version. That means as much as 20 per cent more cutting speed or 30 per cent more tool life.”Copher said the ability of tooling manufacturers to control the crystal orientation keeps the coatings in line with each other. “Controlling the crystal orientation helps the wear resistance, the peeling resistance, and the breakdown of the coating during the machining process.”Visual AdvantageA top layer of coating such as a colourful chrome that wears away to expose the different colour of the layer below can, by itself, provide a significant increase in productivity.“We did a spot check with some of our customers. We would go to a recycle bin, grab a handful of inserts, and check the edges. They were shocked at the number of unused edges that were thrown into the bin,” said Eller. “Simply having used edges visually apparent in contrast to unused edges made it easy for operators to use all edges before tossing an insert. It creates a substantial cost savings.”Some Recent CoatingsUnderstandably, many of the new coatings have been developed to increase production in exotic and difficult-to-machine materials, but not all. Some new coatings boost production for established, more common materials.Iscar’s DO-TECH coating combines the CVD and PVD technologies to create a coating that improves performance when cutting cast iron for milling and turning. Geisel said, “We use a lot of titanium carbides and aluminum oxides. We also use titanium nitride—it’s a good coating to use as a top layer because it’s gold and shows the wear.”Sumitomo’s CVD Absotech™ Platinum coating is a multilayer aluminum oxide/titanium carbon nitride designed mainly to cut carbon steels, tool steels, and stainless steel. Copher said that the Absotech Bronze PVD coating of titanium aluminum silicon nitride is recommended for interrupted machining of stainless steel and exotic materials.Duratomic® from Seco is a CVD aluminum-oxide coating for increased edge toughness, more wear resistance, and smooth surface finishes that are cut with less friction, said Eller. When the insert does begin to wear, the chrome included in its makeup shows the worn edges. Each layer of a nanolaminate PVD coating is approximately 7 nm thick. Varying the individual layer materials and thicknesses makes it possible to adjust the hardness and thermal stability properties. Photo courtesy of Seco Tools LLC.Everything Matters“Whenever we’re working with a manufacturer, we have them show us the machine to be used, specify the material, and show us the workpiece. The workpiece itself is key. Is it an easy shape or some sort of irregular shape that needs counterweights because the part might not run perfectly true? A prime example is the automotive industry because its parts might have lobes or protrusions so they have to be offset when they run. That affects the insert wear. We get a feeling for what type of cutting parameters they can operate safely and then determine the insert and coating. If you run too fast, you can risk throwing a part out of a machine and hurting the operator,” said Geisel.“I’ll ask manufacturers why they are using a particular insert or coating and they say, ‘It’s just what we had.’ That’s understandable if they have only a few pieces to make, but they need to understand that all tooling manufacturers are improving technologies,” Geisel said. “A grade of coating they used 10 years ago is completely different from today’s grades which are much better.”Iscar Canada, 905-829-9000, www.iscar.ca Seco Tools LLC, 248- 528-5457, www.secotools.comSumitomo Electric Carbide Inc., 800-950-5205, www.sumicarbide.com Slide Show | 5 Images