Aggressive action

Upgrades help to cut high-strength materials to tight tolerances, obtain higher yields and lengthen blade life

BY Paul Beha, HE&M Saw

uperalloys are being selected more frequently to replace carbon steel alloys in a variety of applications. Superalloys are specifically designed to have high strength at high temperatures, making them ideal for the aviation and aeronautic industries and other environments where these special properties are required. Superalloys are also more resistant to corrosion, oxidation, and wear and tear.

Composites are a combination of elements in a structure or atomic arrangement, which is often complicated and repeated regularly in the configuration of their structure. Superalloys use the power of “phase variation.” This means that instead of having one atomic arrangement repeated throughout the material, superalloys have multiple atomic arrangements known as “phases.” A simple comparison is water versus ice. Ice has the same molecular composition as water but a different atomic arrangement or phase. The physical properties of the material are much different, even though the molecular composition is the same.

Stop crooked cuts

Many years ago, Gerald Harris, the founder of Harris Engineering and Manufacturing, now known as HE&M Saw, developed a patented feature known as the Cut Watcher. This technology senses blade tracking as it saws through material, reporting the information back to the control. When the blade begins cutting crookedly (varying too far from desired tolerances) due to dulling or excessive force put on the blade, the adjustable sensor reports this, and the control will force the saw to stop cutting and pause the sawing cycle, saving the material. Crooked cutting is exacerbated when cutting tougher materials, such as superalloys. Metals such as Hastelloy, Inconel, A2, D2 and others are expensive, and processors would much prefer being able to save material that would otherwise be rendered to scrap.

HE&M Saw has taken this feature to another level. According to Max Harris, HE&M’s chief engineer, the newest version of Cut Watcher is called Active Cut Watcher. This improved feature tracks, monitors and reports the straightness of the cut and initiates actions to straighten the cut. This feature prevents material waste and improves the efficiency of the sawing process tremendously.

The saw is able to continue the cutting process rather than stopping the sawing cycle due to the blade-track deviation by automatically increasing the tension on the blade using a cylinder to exert additional blade tension pressure. The increased tension on the blade provides for a more rigid blade, helping it to maintain a straight cut longer.

According to Harris, the logic introduced at the machine control will counteract the blade deviation when the blade starts to wander. This enables the blade to continue to cut more aggressively when sawing tougher, harder materials, even as it begins to dull. The ability to monitor the blade track and apply additional tension can keep the cut much straighter through these hard-to-cut materials while retaining the aggressive pressure required to complete the cut and maintain the optimum chip load on the blade teeth.

Advancing accuracy

The Active Cut Watcher will be unveiled on a new band saw model, the DC22HA-CTS2. Another newer feature on this new model is an adjustable servo-controlled saw arm, or SCT. Harris says this feature will allow more precise and consistent force on the blade, providing more control of the blade throughout the cross-section of the cut. SCT is critical for controlling the chip load and, therefore, the life of the blade.

Tests have shown that both features will increase blade life and provide for straight cuts more consistently, even as the blade begins to dull. SCT is an advancement of a previous and still-viable feature called the Computer Controlled Traverse, or CCT, which HE&M has offered for decades.

Our band saws are being designed in line with what has been used in the CNC machine universe.

“With the advances in the accuracy of the saw arm pressure controlled with the new SCT, we can more accurately preprogram our control for efficient sawing of a variety of metals,” says Harris. “Blade speeds and feeds will be stored in a material library on the saw, like before, but sawing with much more precision.”

A third improved feature is also based on an older patented HE&M Saw design: Blade Enhancer. Blade Enhancer has been around for decades and was based on a concept that is often used when sawing by hand. It provides a “rocking” motion to the blade, which is similar to the see-saw motion used when cutting a log using a hand saw. The unique pressure control reduces the surface area contacting the teeth. The concentrated force on fewer teeth reduces cutting time, increases blade life and improves the sawing process when cutting hard materials like superalloys, due to the increased penetration of the teeth.

Blade Enhancer (circled) provides a “rocking” motion to the blade, similar to the see-saw motion used with a hand saw.

Although the problem of crooked cutting and blade life is improved with Active Cut Watcher and Blade Enhancer, HE&M Saw engineers have addressed additional customer concerns. The sheer weight of exotic materials can be an issue when moving the material through the saw in an automated sequence. The material handling improvements have been addressed in a fashion similar to the aforementioned saw arm, by using servo-driven bar feeds. This, along with some other tweaks, has doubled the sawing table’s weight capacity from 10,000 to 20,000 pounds, which is particularly attractive for companies that are cutting large, heavy alloy billets.

Along with these new and updated features, the DC22HA-CTS2 model will integrate into Industry 4.0 functions using MT Connect. The Association for Manufacturing Technology has developed this open-source communication standard to allow a variety of machines to communicate, which facilitates remote machine monitoring and offline job programming.

“Our band saws are more often being designed in line with what has been used in the CNC machine universe, by updating our saw controls and providing higher precision for the primary process of sawing,” Harris says, adding that the machine builder will continue to develop new features.