There’s an old saying that’s true – you can’t fit a square peg into a round hole. Similarly, you cannot expectahere’s an old saying that’s true – you can’t fit a square peg into a round hole. Similarly, you cannot expect exceptional non-ferrous sawing with a saw designed to cut standard steels.
In a perfect world, one saw would offer the highest sawing performance for every possible type of material. Although there are saws that can be quite versatile, realistically speaking, there is just too great a range of material grades for one saw to cut them all exceptionally well. For example, while the best sawing speed for Inconel on a band saw may be at 120 sfm, the best speed for aluminum may be at 4,500 sfm.
Designed for the Job
A job shop that handles a variety of work and materials should strive to find a saw that handles a wide range of materials and cuts them all reasonably well. Of course, the understanding (or tradeoff) is that the speed of cutting, blade life, cost per cut and cut quality over the range of those cuts will not be as good as they would be if they were processed on a saw specifically designed to cut a particular group of materials.
However, when the focus is on production sawing of a certain material range, then the objective should be to find the sawing solution that is based on a machine designed for the most effective sawing of that material. This means the machine base, framework, gearbox, motor, controls, blade size, blade guidance, cooling process, chip collection and many other variables should be designed to offer the most cost-effective and efficient sawing. In other words, not all saws are created equal, and not all material sawing processes are the same.
For a saw to be efficient and cost-effective for cutting non-ferrous materials, it needs to be built specifically for the application from the ground up. It needs to incorporate a number of features that are unique to effective processing of non-ferrous materials, including the motor sizing and its speed and torque range. It also needs to have a very rigid base to build on, proper wheel and blade sizing, a means to efficiently deal with the lighter chips generated in non-ferrous sawing, coolant application, ease of maintenance and so on.
This same philosophy holds true whether you are talking about band sawing or circular cold sawing, as the theory and design processes are applicable to both technologies. For example, simply modifying a steel-cutting circular-saw gearbox to allow for faster blade speeds while keeping all other machine functionality the same will just not work effectively for aluminum. Instead, the design must take many other variables into consideration, such as clamping pressure, blade separation features and a faster feeding gripper system.
Sawing Scenarios
A similar scenario holds true for the sawing of Inconel and other superalloys on a band saw. The most optimal sawing of these materials requires an extraordinarily rigid design that can handle the required blade size and blade tension and offer excellent vibration-dampening characteristics. It also needs to include a positive and consistent downfeed system, be able to sense pressure at the blade and react accordingly, monitor and compensate for square cutting, and offer sufficient coolant application to offset the high heat that is generated in this process.
Again, there are saws available that are versatile and forgiving, and allow for cutting a wide variety of materials. But, there is simply no one saw that does it all at the highest possible performance levels. An aluminum production shop needs a saw that is designed from the ground up for that application, while an Inconel, titanium, superalloy facility will want a whole host of different technologies and features in a saw that will be cutting these exotic materials. When it comes to the production sawing of specific materials, learn about the saw’s design and technologies and don’t settle for a “this saw excels in all applications” pitch.
Sawing Superalloys
“[Superalloys] are particularly well suited for these demanding applications because of their ability to retain most of their strength even after long exposure times above 650°C (1,200°F),” the MMMS explains. “Their versatility stems from the fact that they combine this high strength with good low-temperature ductility and excellent surface stability.”
Superalloys fall into three main categories: nickel-, iron- and cobalt-based alloys. Inconel, which is a nickel based superalloy, was created for the development of the first jet engine – another example of superalloys’ ability to endure high temperatures.
When cutting this high-strength material, a high amount of heat is generated, and because of the low thermal conductivity of Inconel, the heat generated in the cutting process can be transferred from the material to the cutting tool.To manage the heat generated in the process, coolant must be employed.
To simplify the task of choosing a coolant to use, Behringer provides its customers with recommendations that offer the best coolant to use according to the saw in operation. When effective cooling is employed – especially with superalloys – tool wear can be kept to a minimum, allowing fabricators to realize high feed rates and shorter cutting cycles as well as increased tool life.
Keeping Pace
An additional consideration of efficient non-ferrous sawing is the material handling component. For example, machines that are designed to cut aluminum saw much faster, so it’s imperative to keep up with the pace of the equipment and ensure that material is being fed into the saw at an effective rate. With cut times that are dramatically faster on specialty saws, the total part cycle time can only be as good as the ability of the system to get material in and out of the saw just as efficiently. Typically, systems can be fully integrated into the saw to handle everything from powered roller conveying to cross transporting and bundle clamping. Cutting to length, ejection and sorting are also standard for most material handling systems.
Advice on Aluminum
Because of its inherent physical qualities – malleable, ductile and lightweight – fabricating aluminum can be fairly easy. In that same breath, however, the soft nature of aluminum requires a different approach.
To keep from scarring the metal, equipment cleanliness is important. When metal burrs and particles are present on a piece of equipment,
the surface of the aluminum can be susceptible to scratches and other damage. Therefore, fabricators must understand how to efficiently deal with the chips created when sawing aluminum to avoid surface damage.
“When sawing plate, be sure to remove saw chips and cutting coolant-lubricant from the top and bottom surface before stacking the sawn plate on
any surface,” explains the Aluminum Association. “When sawing a number of plates simultaneously, it is important to separate the stack as soon as practical to allow for removal of saw chips that might have been entrapped. Coolant-lubricant must also be removed to prevent staining.”
