Adding further capacity coupled with the benefits of CNC precision and programming flexibility has resulted in HB Bearings Ltd acquiring a further Kellenberger Vista universal grinding machine.

“A highly skilled work force and a commitment to quality are obviously vital but we have always been prepared to invest in state of the art machine tools and this latest Kellenberger investment?—?our 4th CNC grinder?—?is testimony to that,” explains HB managing director Graham Hirst.

And, as Mr Hirst adds, there is more investment imminent. “HB has recently acquired Gamet Bearings who are renowned as manufacturers of super precision taper roller bearings,” he explains. “We are relocating the Gamet operations from Colchester onto our Huddersfield site and further investment in high precision grinding capacity will be necessary. As we are working to 1.5 micron running accuracy tolerances on Gamet products we will be looking to invest in additional Vista CNC machines, such is our confidence in them.” In its Huddersfield production facility, HB has three Vista UR 75/1000 CNC machines now joined by the latest Vista SE?—?all of which have been supplied by Rugby based Jones & Shipman Hardinge Ltd., the UK subsidiary of Hardinge Inc.

The swivelling wheelhead features pre-stressed, high precision spindle bearings to ensure the highest maintained surface finishes and long operational life. Suitable for grinding between dead centres and for chucked work - is a further example of the machine’s progressive design.

HB has also specified a HF-dresser on the upper (x–axis) table.

Highly complex grinding

Designed to be a cost-effective CNC alternative to hydraulically controlled cylindrical grinding machines, Vista machines have simplified the programming sequence thanks to the Kellenberger Kel-Easy and Kel-Iso menu based system delivered via a Fanuc 0i control system.

Key features include the ability to micro-adjust the tailstock in the range of +/-60 ?m, linear guides on the X-axis, a classical slide arrangement in Z-axis and the ability to accommodate a workpiece up to 100 kg in weight. As the designation implies, the distance between centres on the machines supplied to H&B is 1000 mm, as is the grinding length.

The compact design features a coolant tray which is separated from the machine base, an integrated transport system and swiveling upper table. The swiveling workhead?—?being suitable for grinding between dead centres and for chucked work?—?is a further example of the machine’s progressive design. The thermally-optimised bearings guarantee the highest roundness and dimensional accuracy.

“They are highly durable machines but importantly offer the sustained accuracy essential in our business. 5 micron is the norm we work to but we can meet demands down to 2 micron if needed and, as with all the Vista’s, a capability of grinding highly complex, high precision profiles while maintaining tolerances and very high accuracy of concentricity is vital,” explains Graham Hirst.

“The common denominator with all is they are difficult to machine and with the micron tolerances we have to achieve with exact repeatability, the Kellenberger machines are more than up to the challenge,” concludes Graham Hirst. “They have been an excellent investment,” he adds.