If repeat machine tool orders are a sign of confidence in a brand, one of Japan’s leading manufacturers of compressor air systems has clearly demonstrated its faith in the quality, reliability and accuracy of PTG Holroyd Precision’s helical rotor milling and grinding machines.

Having just ordered its third PTG Holroyd TG350 helical thread and rotor grinding machine  – its 14th Holroyd machine in total – the company in question bought its very first Holroyd model, a 2A rotor milling machine, from the UK-based manufacturer way back in 1956. This was quickly followed by several more rotor milling machines and grinding machines, including one of PTG Holroyd Precision’s large capacity 8EX models – a machine able to precision mill helical rotors and pump screws of up to 850 mm (33 inches) in diameter.

“We’re delighted to have established such a solid and long-lasting relationship with the company concerned,” says PTG Holroyd Precision’s Sales Director, Mark Curran. “Our ongoing relationship is testimony to the uncompromising quality of the machine tools we build and the support we provide. Perhaps most impressively, as our Japanese customer has expanded globally, it has stayed loyal to the PTG Holroyd Precision brand, also equipping its new facilities with our machines.”

The latest PTG Holroyd machine to be bought by the Japanese business, the TG350 rotor grinder, will be built at PTG Holroyd Precision’s Rochdale technology centre during 2026, ready for shipping in early 2027. It will be used by the customer to precision-grind screw rotors of up to 350 mm in diameter and 2000 mm in length and will bring even greater levels of capability to the company’s production strategies.

“Our TG Series thread and rotor grinding machines are widely regarded as setting the industry standard for high speed, high accuracy, efficient stock removal,” adds Mr Curran. “Advanced control, integrated safety, reporting and security are ensured through the use of Siemens SINUMERIK ONE CNC. Enhanced connectivity is provided via additional PROFINET interfaces, OPC/UA interfaces and increased performance – all made possible thanks to a PLC that is 10x faster than earlier Siemens controls.”

Equally suited to prototyping, batch and volume production, PTG Holroyd Precision’s TG Series machines are designed primarily for the finish grinding of helical screw components such as worm screws and rotors after they have been milled to a rough or semi-finished state. The TG range starts with the TG50E, a machine designed to precision grind components of up to 50 mm in diameter and 610 mm in length, with models offering stepped increases in capability right up to the production of helical components measuring 450 mm in diameter, 2020 mm in length and weighing up to 700 kg. Each TG Series machine’s advanced automation means reduced setup time, while a significant amount of production time can be saved due to the fact that the diamond dressing discs are continuously dressed during the semi-finish grinding cycles. TG models offer production rates and accuracies to suit precise manufacturing strategies. Fully automated on-machine probing provides closed loop feedback of corrections to the dresser wheel and does not require a high level of operator skill.

TG Series machines at a glance:

• Siemens SINUMERIK ONE CNC
• High levels of accuracy and efficient stock removal
• Developed for prototyping, batch and volume production
• Accelerated and simplified setup
• Fully automated grinding wheel balancing system
• Powerful, intuitive touchscreen programming
• Holroyd 3D CMM component scanning probe with fully automatic compensation feedback
• High-power, high-speed grinding spindles
• Optional hollow spindle for longer components
• Advanced, in-process wheel dressing system
• Large diameter grinding wheels for maximum wheel life
• Optional Holroyd Profile Management System (HPMS)
• Component diameters from 0 mm to 450 mm depending on component and profile

PTG. The first name in precision

Incorporating the brands of PTG Holroyd Precision, PTG PowerstirÒ Friction Stir Welding and Holroyd Precision Rotors, PTG has established itself at the forefront of high-precision machine tool design, build and supply for specialised applications. The range includes advanced machine tools for the production of complex helical components such as compressor rotors, pump screws and high-accuracy gears, and PowerstirÒ machine tools for friction stir welding advanced alloys used in transport applications. With production facilities in the UK, USA and China, Holroyd Precision Rotors manufactures the special purpose, ultra-precision helical components used in a wide range of industries, including refrigeration, air-conditioning, gas and vacuum pumping, industrial air handling, aerospace, medical equipment, motion control, power transmission, power generation, oil & gas, fluid transfer and high-end automotive. PTG also provides advanced technical consulting services.