Leading European compressor manufacturer chooses Holroyd’s ‘two-in-one’ profile milling technology

Revolutionary high-speed Roots-type blower manufacture

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One of Europe’s leading manufacturers of high quality compressed air systems has purchased two of Holroyd Precision’s newly developed 4EX-R-BL (BL = blower) CNC profile milling machines.

Built at Holroyd’s UK technology centre in Rochdale, 4EX-R-BL models are effectively two machines in one as, in addition to producing helical rotors, they can be programmed to precision-mill straight-fluted components as used in Roots-type blower ‘air ends’.

Holroyd sales manager, Mark Curran, said: “Since announcing their launch, we have received considerable interest in the capabilities of 4EX-R-BL models from manufacturers who wish to achieve high levels of efficiency.

“As you can imagine, it was therefore particularly pleasing to then secure two machine orders from one of Europe’s leading manufacturers of compressor systems. The company in question required the flexibility to cut both helical rotors and blowers, and the 4EX-R-BL machines more than fitted the bill.”

For some time, Precision Technologies Group business, Holroyd Precision, has been looking at how it can further extend the capabilities of its EX Series milling machines, to enable their high speed, high precision and high performance to be applied to the manufacture of Roots-type blowers.

The company believes the new model will revolutionise the way in which straight fluted, infinitive lead rotors are milled, significantly reducing manufacturing time and increasing the accuracy of the production process.

Although sitting within Holroyd’s EX range of rotor milling machines, the 4EX-R-BL is in fact a totally new machine that has been designed from the ground up. As well as being equipped to mill helical rotors of up to 450mm in diameter, the 4EX-R-BL will rough mill blower blanks of around 320mm in diameter and 900mm body length into straight fluted rotors in 30 minutes floor-to-floor, ready for finish profile milling to absolute size. This represents a significant time saving when compared to the one-and-a-half to two hours typically required to cut individual Roots-type blower rotor flutes using traditional milling techniques.

Totally removing the need for manual intervention or indexing during the milling of each flute, the Holroyd 4EX-R-BL features a bespoke steadying system that has been designed to withstand the additional forces that are generated during the milling of straight flutes. Specially developed ‘finger clamps’ ensure the workpiece is held securely while a flute is being milled, then release to enable automatic rotation and positioning ready for milling of the next flute.

Mr Curran added: “In what has been a genuine ‘from the ground up’ development of a completely new kind of machining centre, in the 4EX-R-BL we have designed a model that is able to produce all helixes from horizontal to vertical, for helical rotors, infinitive lead blowers, helical blowers, compressor rotors and vacuum pumps,.

“This significant level of versatility makes the 4EX-R-BL well suited to manufacturers who perhaps make different rotor types and therefore need considerable flexibility in their machining technologies, as well as providing a new, highly superior manufacturing solution for producers of Roots-type blowers.”

Incorporating the brands of Holroyd, Holroyd Precision Rotors, Binns & Berry and Crawford Swift, PTG has established itself at the forefront of high precision machine tool design, build and supply.

The PTG range includes ultra precision grinding machines for rotor, thread and gear operations; rotor milling machines; heavy duty lathes; deep hole boring machines; friction stir welding machines and special purpose machine tools for the manufacture of precision components. Industrial sectors served range from aerospace, medical and mould tool and die to marine, power generation, mining, oil and gas, steel, high end and heavy automotive.