A leading Chinese manufacturer of industrial refrigeration compressors has chosen a British-built PTG Holroyd TG Series CNC rotor grinding machine to bring even higher levels of accuracy and speed to its manufacturing strategies. Valued in excess of £1.4 million, the machine, a TG350E, will be built at PTG Holroyd’s Rochdale-based technology centre, ready for commissioning in summer 2022. It will be used by the customer to precision-grind stainless steel screw rotors of up to 350 mm in diameter and 1800 mm in length.

“We are delighted to announce this significant export order, which follows on from a number of sales of our PTG Powerstir friction stir welding machines to overseas customers,” comments PTG Holroyd Sales Director, Mark Curran. “Although we are not able to name the compressor rotor manufacturer, it is rewarding to know that the uncompromising levels of accuracy provided by our rotor grinding machines were a significant factor in them choosing the TG350E.”

PTG Holroyd TG Series machines are widely recognised as providing the industry benchmark for high-speed, high-accuracy, efficient stock removal. Advanced automation means reduced setup time, while a significant amount of production time can be saved due to the fact that each machine’s diamond dressing discs are continuously dressed during the semi-finish grinding cycles. 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 up to the production of helical components measuring 450 mm in diameter and 2020 mm in length.

Equally suited to prototyping, batch and volume production, 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. 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 rotor grinding machines, at-a-glance:

• 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 touch screen programming
• Unique on-board 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
• Maximum component weight: 700 kg

PTG. The first name in precision

Incorporating the brands of PTG Holroyd, PTG Powerstir 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 Powerstir 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.