VALVE MANUFACTURER AUTOMATES PRISMATIC MACHINING TO COPE WITH INCREASED DEMAND

In the five years from 2019 to the present, turnover at Oswaldtwistle-based Ross Pneumatrol doubled to £7m due to growth across most sectors into which it supplies its pneumatic and electro-pneumatic valves, actuators and other products. The oil and gas industry is proving especially buoyant currently and sales growth in Asia has exceeded expectation, raising the proportion of exports to more than 60% of turnover.

This level of success was putting pressure on the prismatic machining department, which was using six 40-taper, three-axis vertical machining centres (VMCs) of various makes and three Brother 30-taper machining centres with twin pallet changers supplied by Whitehouse Machine Tools. To meet increased demand for prismatically machined components, notably valve bodies and pilot end caps, Ross Pneumatrol returned to WMT CNC for two more Brother 30-taper machines, this time with automated component handling.

The first cell, installed in the aluminium machining section in September 2022, comprised a Brother Speedio S700X2 VMC equipped with a Feedio robotic system, including vision equipment, for handling components. Designed specifically to automate Speedio machining centres, the plug-and-play unit communicates with the S700X2 via a Profibus interface and incorporates a six-axis robot. A camera vision system and built-in PC allow the robot to detect where on an upper conveyor the workpiece sits. After machining, components return to an output conveyor positioned below the first.

Tommy Cooney, Ross Pneumatrol’s operations manager, says: “We considered several different machine tending alternatives but decided to reorder from Whitehouse Machine Tools. We have dealt with them for more than 20 years and value their aftersales service and engineering input. In particular, we liked the ability of the Feedio unit to handle components in and out of a second Brother VMC when the need arises in the future. No other potential supplier was able to offer that facility.”

Encouraged by the success of the first automated cell, Ross Pneumatrol decided to install a second to produce similar components in stainless steel. Consideration was given at the outset to retrofitting a collaborative robot (cobot) to one of the existing 40-taper machines on the shop floor, as it was thought that cutting the tougher material would need a more robust VMC. This approach would have been expensive, however.

Instead, Whitehouse Machine Tools proposed a Brother Speedio F600X1, which although being a 30-taper machine is nevertheless a high-torque production centre capable of cutting stainless steel 24 hours a day. Rather than choosing another Feedio for automation, at the instigation of Whitehouse Machine Tools, the manufacturer chose a CubeBox from Turkish OEM Tezmaksan, for which the machine supplier is UK sales agent and integrator.

As with the Feedio unit, CubeBox has a six-axis robot to handle parts directly, rather than basing the automation on more expensive exchange of pallets with fixtured components. Moreover, because the 20 or so variants of stainless steel valve body and pilot end cap are fundamentally cuboid in shape, as in the aluminium cell, the parts are easy and quick to grip for transfer to and from a machine tool.

Cooney and his colleagues have no hesitation leaving the two automated Brother machines running unattended from the end of the second manned shift at midnight to the start of the first shift the following morning at 06:00.

“The F600X1 is a versatile machine, as it is able to cut not only stainless steel but also softer metals,” says Cooney. “This fits well with our production pattern, as stainless steel products account for about 10% of throughput, so we’re able to maximise the F600X1’s utilisation by cutting aluminium as well. The entire cell did not cost much more than fitting a cobot to a 40-taper machine would have done, so we’ve gained an extra, highly productive spindle for just a small amount of additional expenditure.”

He advises that cycle times on the two latest Brother machines with their higher specifications are about 40% faster than on the older 30- and 40-taper machines. Aluminium pilot end caps and bodies take seven and 10 minutes respectively to complete, while cycle times for the stainless steel versions are 15 and 18 minutes. The machines easily hold the drawing tolerances of ±0.02 to 0.05 mm.

Ross Pneumatrol particularly values the engineering support from Whitehouse Machine Tools. The company involved the supplier in time studies, applications engineering, the provision of mainly Ceratizit carbide tooling, and offline programming strategies using Fusion 360 CAM software. These services continue indefinitely, free of charge, for as long as the user requires them.

The Tezmaksan CubeBox increases production output by up to 50% compared with manual loading and unloading, additionally allowing long periods of unattended machine running, including overnight. It is 20% less expensive than a company-specific robot integration system. The plug-and-play solution can be implemented on a shop floor the same day as it arrives, without any need of robot programming knowledge. It is suitable for serving one or two CNC machines of any make and is adaptable to all brands of control system and robot.

The unit installed at Ross Pneumatrol is a CubeBox Blues DR, whose FANUC M10iD/12 industrial robot has a maximum payload of 12 kg. The workpiece storage system includes five drawers for holding parts up to 135 mm in height. A FANUC R‐30iB Mate Plus control unit, RoboCAM smart automation software, collision avoidance and a safety light curtain are all standard equipment.

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