A newly developed ‘large diameter' CNC cutter grinding machine from Holroyd Precision Ltd is designed to bring considerable advantages to organizations that wish to achieve greater levels of accuracy and repeatability when finish milling some of the world's largest helical rotors.

Called the CS700E Tool Management Center, the new machine has been designed for the grinding of high-accuracy profile forms on finish milling cutters of up to 700 mm in diameter and follows up on Holroyd's CS500E (500 mm max. diameter) model.

"The new CS700E machine is generating considerable interest," comments Holroyd Sales Manager, Mark Curran. "Indeed, a major compressor manufacturer that has only recently purchased its second Holroyd 8EX rotor milling machine (for producing rotors of up to 850 mm in diameter), has already placed an order for a CS700E."

"The accuracy of any helical screw form relates directly to the accuracy of the cutting tool that is used to create it," continues Mark Curran. "Through the development of the CS700E Tool Management Center, we are enabling producers of larger helical components to benefit from complete control of all aspects of the cutting tools they use. The CS700E produces high accuracy profile forms on a wide range of tool materials, from traditional high-speed steel, to exotic materials such as carbide and ‘AS' finish machining systems."

The CS700E Tool Management Center incorporates automatic dressing stations to ensure optimum integrity of the grinding wheel at all times. The stations are equipped to dress aluminum oxide, CBN and diamond grinding wheels, while use of HSK-A160 arbors (as fitted to 8EX rotor milling machines), enable rapid wheel changeover times and further enhance accuracy.

At the heart of the CS700E is Holroyd's user-friendly advanced touch screen programming system. This provides complete control over production accuracies, as well as invaluable on-screen modification of profile forms for the rapid evaluation of new profile shapes during the development and prototyping stages. Profile modifications are easily made thanks to the menu-driven system, which provides control of the cutting profile, with on-screen modification of profiles.

Automatic touch probing of the tool profile during the grinding cycle is another major benefit provided by the CS700E. Following probing, the actual tool profile is graphically superimposed over the theoretical profile and displayed within user-defined tolerance bands to ensure that all cutter blades are ground within tightly controlled limits. Indexing and multi-pass grinding/trimming cycles are also fully automated.

Cutters with up to 29 blades can be sharpened on the CS700E Tool Management Center. The cutter indexing process is carried out automatically. The cutter is located on an HSK-A160 arbor for precise positioning on the 8EX rotor milling machine, or on other rotor millers employing the same arbor. The maximum profile height is 120 mm.

Designed and built at Holroyd's UK-based machine tool development center, the CS700E features an ergonomic design, a solid cast iron base for outstanding rigidity and excellent thermal stability. Total machine guarding offers flood-cooling capability. There are large sliding doors for ease of set up and separate rear/side access for workpiece loading. The CS700E is also equipped with a recirculating oil mist removal system.