As a saw blade cuts its way through metal, some amount of noise can be expected. However, if it’s so loud that hearing protection is required, it could be a big indication that the blade isn’t cutting efficiently, which means the life of the blade is compromised and the quality of the cut could be in equal jeopardy.
Getting the tooth geometry on the saw blade dialed in requires a fair amount of research and development. However, that’s exactly what it takes to ensure a quality cut at an efficient feed rate in a blade that will last. While metal fabricators don’t buy saw blades because they’re quiet, it’s one of the factors that plays into efficiently cutting through thick metal billets.
Roughly a year and a half ago, Chandra Sekhar Rakurty and Pete Vandervaart, senior product development engineers at M.K. Morse Co., set out to engineer a carbide-tipped blade that cuts 8-in. to 35-in.-thick billets faster than traditional carbide blades and with reduced harmonics. By reducing harmonics, they knew they’d also reduce noise as the blade makes the cut.
Rakurty explains that there is “X” amount of energy a saw provides for a blade to make a cut and that the energy needs to be properly distributed. Improperly distributed energy results in an increase in sound.
“If you are making sound, that means you are wasting energy,” Rakurty says. “Instead of cutting, you’re using the energy to make noise – you’re losing your cut efficiency.”
In the Grind
Rakurty and his team studied the harmonics and vibration through a series of high-tech analyses, which included the use of optical equipment made in-house to carefully study how the blade was wearing. To reduce the harmonics, they sought to correct the amount of overhang and the amount of kerf, which drove them to develop a patented process to perfect the tooth geometry for which they were looking through precise shaping of the teeth on the blade.
“It’s so quiet,” Rakurty says of the finished GES (ground exotic set) blade, adding that users require no hearing protection while cutting billets. “You can have a normal conversation while the bandsaw is cutting.”
In a traditional carbide-tipped blade construction, the carbide is ground and then the blade is sent off so the teeth can be bent to the geometry that will provid the grinding process is exacting, Rakurty says the bending process is “not very controlled”, so the question became – could they use the preferential grinding process to set the tooth geometry, as well?
“The grinding process is very precise,” he says. “It provides good control over how much kerf you have and what the carbide geometries look like. That’s where we came up with the patented design – the preferential grinding of the carbide so each tooth takes a small, precise bite, which is much better than set-tooth carbide.”
Rakurty explains that another benefit of GES blades over set-tooth carbide blades is that the chip distribution is more consistent.
“If you look at the chips,” he says, “they are really thin, continuous and break off very easily. That’s one of the things we’ve been working on, as well: creating consistent chips rather than sporadic chips. Sporadic chips are a sign your blade is failing. When you consistently create the same type of chip over and over again, that means your performance is consistent, resulting in a better finish.”
Clearly, for a product aimed at cutting thick billets, finish isn’t of upmost importance. However, compared to set-tooth blades, Rakurty says the GES offers a “very good finish.”
And a smoother finish can be achieved with the GES blade by slowing down the feed and speed, but again, the customers most interested in this blade aren’t interested in running slower – they’re looking for a quality cut, but at the speed advantage the GES offers.
The GES blade was introduced to the public in March 2018, but some customers used it for months during a prior trial phase. Rakurty says the blade passed customer trials with flying colors every time without a single failure in expected performance.
Since then, customers have continued to give it positive reviews. Joan Bennett, product manager at M.K. Morse, says “rock star” is one of the regular descriptions that it gets.
The Wide Set
Another GES product development is for heat-treated materials, such as those associated with forging centers. Rakurty explains that these materials, often used in aerospace, are heated and compressed, which can be a problem when cutting as the blade tends to pinch. More often than not, this situation can be damaging to the blade as well as the material being cut.
This led to the development of the GES WS (wide set), which is projected to be released in late November or early December.
In developing the GES WS blade, Rakurty and Vandervaart went through the same research and design process to achieve a tooth geometry that could significantly reduce harmonics. Successfully, they identified that the wider set teeth could work through thick billets of heat-treated material. The wide-set teeth allow for the removal of more kerf, which helps reduce the likelihood of the blade getting pinched.
The GES blade is available in 18 sizes, from 1.25 in. to 3 in. The company also provides a speed and feed chart for carbide-tipped blades available here. Users simply need to know what kind of bandsaw they’re using, the type of material they’re cutting and its thickness.
Obviously, if it’s a heat-treated product, it will require the WS version, which will be offered in a smaller number
of sizes when it launches, but will eventually come in more sizes for billets 10 in. or more in length.
“The key selling points are longevity,” Bennett concludes, “reduced downtime thanks to the blade’s extended life and confidence in the repeatability of the cut. It also offers high performance on exotic materials.”