HE&M recently completed a large plate saw, the PS-31-120-CTS model, which exemplifies the transition from a custom saw to one that will likely be added to the regular band saw lineup.

In 2014, we were contacted by a manufacturer whose needs were not reflected in the capabilities of any of our basic models. Our engineering team worked closely with the customer to accurately evaluate their needs. The resulting requirements produced a large plate saw that was capable of sawing blocks or slabs up to 25 in. high, and with a throat depth of 31 in., it could cut a broad swath of material.

At the end of 2019, we were contacted by another company that needed a saw with very similar requirements. About the only difference between the original application and the new one was the length of material the machine was required to support and cut. With a few additions and updates, the PS-31 was called upon again as the saw model that could fulfill the customer’s requirements. The new saw was updated and outfitted with a catwalk for easier operator access.

Safety gates and interlocking safety switches, to monitor the gates’ open/closed condition, were included. Two pendant controls were added to allow the operator faster and safer positioning of the saw arm relative to the material and even to make changing the blade process quicker and more natural.

Tale of the tape

The latest version of the PS-31 saw, at 65,000 lbs., can be accurately described as massive. At 14½ ft. tall, the saw will require partial disassembly for shipping, then reassembly at the customer’s location. The base alone weighs 25 tons, but that solidity creates a stable, secure platform for handling large parts.

The PS-31 can support material for sawing up to 25,000 lbs., and with a working height of 7.5 ft., even the tallest basketball player could stand under the saw’s cutting surface. The work height is the point where the slab sits for sawing. On this saw, it needs to be high because the beam that provides stability to support the table requires that amount of space to fit and the height capacity of the saw requires an arm that is tall. It has to extend below the cutting surface so the cutting surface has to be high enough to accommodate the length of the arm and the bottom saw wheel.

Because many applications involve cutting high-strength steel, such as A2, D2, 316L stainless and other materials, controlling the sinewy swarf is critical. To help prevent the stringy chips produced by the blade from sticking or piling up, a high-pressure coolant pump blasts the blade clean. A separate fluid reservoir for the high-pressure system is stored independently in a 55-gallon container; fluid reservoir levels are electronically monitored and regulated. The low-pressure system that dispenses the normal cutting fluid during sawing has a capacity of almost 300 gallons.

Controlling the monster

Controlling the PS-31 is an Omron PLC and touchscreen combination. With variable force and feed rates, the saw’s motion is driven by an integrated motion controller. The saw arm is servo driven using a rack-and-pinion drive system.

The machine is capable of speeds as slow as 5 thousandths of an in. per min., which might be difficult for the eye to detect but is necessary for sawing the specialty materials that this machine is designed to cut. The fastest cutting rate that can be achieved is 20 in. per min. The arm can be moved rapidly or “sprint” to get it closer to the material before it starts sawing in free space (not in the cut). The arm also has to be moved out past the end of the table to allow the arm to clear and swing around to replace the blade during blade changes.

Incidentally, this servo cut control was prototyped and perfected on the machine built in 2014 and has been running well in a production facility now for over five years. Because of that success, the servo cut control has been implemented in a wide range of other machines such as our double-column series and our horizontal saw models. The wide- flange and vertical saws also have the potential for adopting this system.

No doubt, as time goes on, HE&M Saw will again have the opportunity to design and manufacture band saws and material handling systems that fit a customer’s specific needs and, in time, offer that design in our standard lineup.