Making the Grade: How Insert Grades Work

When it comes to optimizing your metalcutting operations, the first place to look is the point of contact: the cutting edge of the tool. And in modern manufacturing, that often means an insert. Most manufacturers understand the exterior features of an insert, like wiper flats, chipbreakers and other elements of an insert’s geometry. The grade, however, describes an insert’s surface treatment and interior composition, and it may be the most important aspect of how an insert performs in various materials.

Since the 1920s, cemented carbides – primarily made from an alloy of carbide, usually tungsten, and cobalt – have been the material of choice for inserts. And the ratio between the carbide and cobalt can be best understood as a compromise between toughness, or resistance to chipping and fracturing, and hardness, or the ability to resist wear and maintain an edge. The more cobalt, the greater the toughness; the more carbide, the greater the hardness.

Furthermore, many grades feature additional materials. For example, steels require much greater hardness, especially at high temperatures, and cubic carbides such as titanium carbide, tantalum carbide and/or niobium carbide can improve chemical stability or grain-size control to achieve that goal at the cost of reduced toughness. But for greater customization, inserts require coatings, most of which arose in the 1970s in order to further increase chemical stability and surface hardness.

In contemporary machining of ferrous materials, uncoated inserts have become rare. Instead, manufacturers opt to use a variety of coatings to achieve greater material removal rates. For thick coatings that include aluminum oxide (Al₂O₃), chemical vapor deposition (CVD) creates highly wear-resistant inserts at the expense of toughness; physical vapor deposition (PVD) creates thinner coatings such as titanium aluminum nitride (TiAlN) that maintain inserts’ edge strength and smoothness at the cost of providing somewhat less protection from wear and cratering.

Some grades, such as those produced with Seco’s DURATOMIC™ coating process, have additional features that positively affect machining. DURATOMIC involves an a-based Al₂O₃ coating with uniquely arranged aluminum and oxygen atoms. This so-called “textured coating” produces a grade with improved mechanical properties and greater thermal and chemical inertness without a significant loss of hardness.

Other grades dispense with cemented carbide altogether. Cermet, a material with excellent build-up resistance produced by combining metals and ceramics, is ideal for creating high-quality surface finishes in stainless steels despite being somewhat less tough overall than coated carbides. Likewise, pure ceramics, polycrystalline cubic boron nitrides, polycrystalline diamond and diamond coatings have numerous advantages over typical cutting tool materials, but have alternate requirements that may interfere with upstream or downstream processes within the entire manufacturing cycle.

How, then, should operators approach insert grade selection? The easiest solution is to rely on your tooling partners at Seco, which provides comprehensive, proven recommendations based on machining strategies and material properties. With the Suggest tool at secotools.com, it’s easy to find the grade that’s perfect for your application, while our Machining Navigator catalogs include all the information you need to find the right solution for your process. And should you have any questions, your local Seco distributor can help you find the answer. 

What Gives the Double Quattromill Its Face Milling Aggressiveness?

The latest addition to Seco’s range of face milling tools, the Double Quattromill 22, is extremely aggressive in terms of performance. How aggressive? For roughing and semi-finishing operations, this cutter can boost depths of cut to as high as 9 mm (0.35") with its 45° rake angle version and to 11 mm (0.43") with a 68° version. In machining, these aggressive cuts mean equally aggressive cost savings, especially when performed using a cutter with eight multi-cutting-edge inserts.

Perfect for today’s machine tools with powerful milling capabilities, the Double Quattromill 22 achieves its aggressiveness through a number of design features that elevate these tools above and beyond the competition. The first feature most machinists will notice is the Idun cutter body, an environmentally friendly alternative to the more common nickel coatings found on most cutter bodies. An exceptionally durable, corrosion-resistant tool steel, Idun adds considerable longevity to the cutter’s overall lifespan, and with a special post-treatment, the tool’s tough surface finish resists marring when handling or machining. The cutter bodies are available with diameters ranging from 3.0" to 12.5" (80 to 315 mm).

For additional durability and productivity, Seco designed the Idun body to include features like patented flute surface textures and flute spacing configuration for improved chip evacuation. Perhaps the most important aspect of the design, however, is the high-axial rake angles. Unlike other cutters with double-sided inserts, the Double Quattromill 22 produces lower cutting forces and requires less machine power consumption than the competition. The 45° lead angle version of the cutter provides the lowest cutting forces, while the 68° version can be used closer to walls or part fixtures while still providing greater depths of cut than a shoulder mill.

In addition to two lead angle options, manufacturers can also select Double Quattromill 22 bodies with fixed pockets in two different pitch options – standard pockets with differential pitch for good chip evacuation and reliable performance on less powerful machines, and close-pitch pockets for high-feed cutting with short-chipping materials – or cassette-style pockets for run-out reduction. All of the cutter bodies feature through-coolant designs.

The Double Quattromill 22’s inserts have also been designed from the ground up for highly aggressive face milling, with three free-cutting inserts available per rake angle type. The ME12 geometry is ideal for sticky materials like titanium and stainless steel, as well as operations that require operators to overcome horsepower limitations. The M12 geometry features a sharper edge suitable for some tool steels and superalloys in addition to stickier materials, providing good flexibility without raising cutting forces. Lastly, the M18 geometry has the best edge protection for abrasive-to-machine materials, beneficial when cutting parts from steels, tool steels and cast irons.

Interested in learning more about the Double Quattromill 22? Contact your local Seco sales representative or visit www.secotools.com.

When It's Time to Turn to Engineered Solutions

By Bob Goulding, Machine Tool Business Development Manager and Tom Funke, CET Manager

Never before have we in the manufacturing world had to do more with less. Shops across the country face skilled labor shortages, demanding customers, unforgiving production schedules as well as the increasing complexity of parts and the equipment used to produce them. All this while experts tell us that we need to “constantly improve,” a goal that’s tough to reach when all you can do is react to the latest challenge.

Seco can help. Our Engineered Solutions team represents a company-wide commitment to comprehensive support for your operations – we sweat the process optimization details and you reap the profits without disrupting your work in the slightest. Our best and brightest engineering minds work hard to develop comprehensive solutions, and the results – an increase in productivity of 25 percent or more – speak for themselves.

To obtain the best results, shops must begin with the part and ask themselves what is the most optimized way to produce it. And whether a situation involves a new or existing process, our experts will then meet with yours so we can get a thorough understanding of your needs and goals. We’ll take all that information back with us to our headquarters in Troy, Michigan, where the Engineered Solutions team will get started on your project.

Our workflow begins with a simple question: “What is the most efficient result that can be obtained with these inputs?” We usually find our answer after a quick look through the archives; few projects today involve any real unknowns for Seco. Instead of spending valuable time reinventing another wheel, we apply our expertise to the customer-supplied data and evaluate cost-per-unit, projected cycle times, machine capacity and other factors to create a documented process.

After we’ve finished our research, we present our findings directly to you in the form of a complete proposal. This is no simple summary of our investigation – our Engineered Solutions team will describe exactly how to optimally produce the part, including the equipment used and how to apply it. We not only define the best cutting processes, but also the best machines, tools and accessories as well as the optimized cutting data.

With your approval, we’ll then go on to turn the plan into a reality. We’ll quickly build any required custom products in our 35,000-square-foot, state-of-the-art production facility in Troy, conduct runoffs, then have it delivered directly to your facility. Our Engineered Solutions staff will be there when it’s time to install any components and initiate the new process. As far as Seco is concerned, we’re not finished until you are running parts that meet your exact specifications.

Even after the project is “finished,” we remain fully committed to your continued success. A new process is useless without someone to manage and maintain it, so our training staff will be on hand to work directly with your operators on the process and to fine tuning cutting data. Likewise, even after you have all the aspects of the process set up and running smoothly, Seco will remain a resource you can call on any time you have a question or need support.

Now is the time to join the many other shops that have enjoyed cycle time reductions or cost-per-unit savings of 25 percent or more upon optimizing their part processes with Seco. And since there’s no cost to you until after you’ve accepted our proposal, choosing Seco as your process optimization partner is a no-brainer. For more information, talk to your local Seco salesperson or contact Engineered Solutions directly by phone at 1-800-896-2593 or by email at epd@secotools.com.