Job shops where sawing is a key component face a variety of challenges from working with a new material to keeping up with fluctuating demands and everything in between. Saw blade
manufacturers understand these challenges and are, therefore, tasked with delivering a variety of solutions, including creating blades that cut faster and last longer.
Lenox, a leader in carbide cutting performance, recently released Gen-Tech, a carbide-tipped bandsaw blade. And while it’s a general-purpose blade (thus the “Gen” in the name of the blade), it has an innovative design and cutting technology that leads to long blade life and a lower cost per cut.
Designed for versatility, the Gen-Tech blade cuts many types of material in a variety of shapes and sizes. From stainless steel and tool steels to titanium and nickel-based alloys, the blade is a good match for many industries, including aerospace, defense and energy.
Dan Fernandes, senior product manager at Lenox, says pre-pandemic, the aerospace industry was “very hot.” Given that the industry is known for utilizing superalloys, Fernandes says Lenox saw an opportunity to cater to an audience that had been underserved.
Another audience that benefits by the introduction of Gen-Tech blades is job shops where the saws are primarily equipped with bi-metal blades. Fernandes says some of these shops are looking to improve productivity with faster cut rates, but their saws aren’t optimized for carbide, meaning they have a greater amount of vibration, which can be detrimental to the life of a carbide-tipped blade. While settings on the saw can help to reduce vibration, Gen-Tech’s durability makes vibration less of an issue.
There’s also the cost barrier. Bi-metal blade users are reluctant to switch over to the more expensive carbide blades, but, fortunately, the Gen-Tech line has a friendlier price tag, which helps overcome that cost-based barrier.
“We noted that there are operators that aren’t used to running a carbide blade,” Fernandes says, “so they need to have something more forgiving. Our customers were asking for a product to meet those needs and at a price point that offered a lower cost per cut.”
Another significant issue Gen-Tech blades help to alleviate is the concerns associated with cutting through billets. “Billet pinching,” says Kevin O’Keefe, lead engineer at Lenox, is the result of billets having high internal stresses, which is a side-effect of the metal casting and forging processes.
“As a saw blade cuts through a billet,” O’Keefe explains, “it often relieves internal stresses, causing the cut to close and pinch or bind on the blade.”
Lenox addressed the pinching/binding issue by making the Gen-Tech product line with an extra-heavy tooth configuration, which helps to fight pinching by creating a wider cut or kerf.
For manufacturers cutting nickel alloys, titanium alloys and even high-nickel aerospace alloys, one challenge they face is that oftentimes, these alloys do not efficiently transfer heat into the
chip during the cutting process, which “causes heat to be concentrated into the cutting edge,” O’Keefe says. “The heat and pressure created while cutting causes the layer below the cutting edge to become work hardened, particularly with high-nickel aerospace alloys.
“The higher cutting temperatures and work hardening require slower cutting speeds so the cutting edge doesn’t rapidly break down,” he adds. “This makes cutting times much longer.”
To resolve this issue, Lenox utilizes two important processes in the manufacture of its Gen-Tech line. The first is Wave Tech, Lenox’s patent-pending process, where the back edge of the blade is chamfered to reduce stress risers and band breakage. The back edge of the blade is also enhanced with Wave Tech to allow for a larger penetration zone, which limits tooth strippage. The second Lenox technology, called Honex, is a process where the cutting edge is pre-honed, which minimizes chipping. Also, utilizing a more resilient carbide adds to the blade’s durability.
“The tough grade of carbide and the Honex edge preparation,” O’Keefe says, “in combination with the overall tooth geometry and pattern design make Gen-Tech blades very chip resistant.”
Almost all saw blades require a “break-in” period. Initially running them at slower speeds and feed rates essentially primes the tips of the blades and helps them last longer. This break-in period is especially critical for carbide blades. Fortunately, Honex edge prep during manufacture helps to reduce the break-in time on the Gen-Tech blade. And O’Keefe adds that the Wave Tech and Honex technologies, in combination with the overall tooth geometry and pattern design, results in a blade that is “very fracture resistant.”
O’Keefe also mentions a couple of operator best practices that should come into play for improved performance. One of the top concerns is vibration. When the operator observes excess vibration, he recommends reducing the cutting speed until the vibration is eliminated. Another best practice is to provide adequate volume, concentration and cleanliness of cutting fluid at the cut.
“The cooling and lubrication reduce the cutting temperature and the tendency of chips to weld to the cutting edge,” O’Keefe says.
Carbide-tipped bandsaw blades are made primarily of carbon and metal, generally developed at high temperatures of 2,700 degrees F or higher. Tungsten carbide and titanium carbide are two common types found on cutting tools, including the tips of bandsaw blades. With the Gen-Tech line, Lenox uses “an advanced grade” of carbide.
O’Keefe and Fernandes are willing to explain just about every aspect of the research and development of Gen-Tech blades, but when it comes to discussing the specific grade of carbide used, they will only refer to it as the part of the “secret sauce.” O’Keefe does offer that they worked with a carbide supplier on the Gen-Tech product and were the first to use this particular grade of carbide.
“It takes a lot of expertise to look at somebody’s carbide and figure out exactly what it is,” O’Keefe says. “Knowing the percentage of cobalt involved is one thing, but there is a whole universe beyond that concerning grain size, mixture and other components, like titanium carbide. Additionally, there are many different technical characteristics that go into the materials and manufacturing of carbide cutting edges that combine to determine its performance in any given application. We’re always testing new grades of carbide.”