The inventor of the hydrodynamic bearing more than 100 years ago, Michell Bearings is constantly developing its product range to meet the ever changing needs of a global customer base.

Today, the South Shields-based company has a reputation as a world leader in the field of bearing design and manufacture for both the industrial and marine sectors.

As the efficiency, reliability and longevity of any bearing depend largely on the quality of the methods used in its manufacture, Michell Bearings uses a wide range of high-tech CNC machine tools and advanced production aids.

The recent installation of a Hermle C60 UMT five-axis CNC machining centre prompted manufacturing engineering manager Chris Kemp to contact Tony Lewis of Aylesbury-based Thame Workholding (www.thameworkholding.com) to explore work-holding ideas that would maximise the potential of the new machine.

Mr Kemp said: “As a leading designer and manufacturer of self-contained white-metal bearings, as well as PTFE-faced hydrodynamic bearings, the company has products that can be found in a wide range of challenging applications.

“We have a long history of producing bearings that withstand the test of time, and we have products installed with 35 of the world’s navies and on more than 300 vessels.

“Our new Hermle machining centre has a work envelope of 1,200 x 1,300 x 900mm and accommodates workpieces weighing up to 2,000kg.

“After studying our new machine’s specification in conjunction with Mr Lewis, we concluded that a work-holding arrangement incorporating Thame Workholding’s Lang QuickPoint system and Samchully jaw boxes would be ideal for our needs, considerably reducing our new machine’s set-up and job change-over times, while also ensuring that we consistently achieve the required levels of accuracy and surface finish.”

‘Slave’ plates

The work-holding arrangement that Mr Lewis devised consists of several circular ‘slave’ plates that can be set up off-line. These plates have Lang QuickPoint studs attached to their bases; a QuickPoint plate remains loaded on the machine table.

The slave plates also feature T-slots that allow Samchully jaw boxes to be moved into position, tightened onto the workpiece then centralised ready for loading onto the machine.

On completion of a machining routine, the ‘slave’ plate holding the finished part can be removed by crane and the next ‘slave’ plate, holding the new workpiece, can be lowered into position and quickly secured to the machine’s table.

It helps that the Hermle’s spindle can move clear to allow unrestricted access to the table.

Mr Lewis said: “Our QuickPoint location system is a rapid and accurate clamping arrangement with a low ‘profile’ of just 27mm.

“It is based on four wedge bolts in the pallet that engage with four grooved locating bolts screwed to the vice or fixture.

“The highly repeatable nature of QuickPoint ensures that Michell Bearings’ ‘slave’ plates can be loaded with workpieces away from the machine, then quickly and precisely attached to the Hermle’s table.

“Being able to load fixtures while the machine is running helps to maximise machining efficiency.”

Thame Workholding designs, manufactures and supplies a wide range of standard and bespoke work-holding products; the company also offers a range of work-holding solutions from leading global manufacturers — such as Lang Technik, Horst Witte, Samchully and HWR Spanntechnik — on an exclusive UK agency basis.

To ensure that its in-house-manufactured products are cost-competitive, effective and of high quality, Thame Workholding uses a range of modern three-, four- and five-axis machine tools with multi-pallets and automated loading for unmanned machining.

The company’s manufacturing facilities are complemented by a CMM-based inspection capability, as well as 3-D CAD and CAM facilities. Thame Workholding has the ISO 9001:2008 quality standard.