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Making measurement solutions for demanding applications

Advanced grinding capabilities enable Taylor Hobson to achieve high levels of geometry and finish

Posted on 16 Nov 2021 and read 602 times
Making measurement solutions for demanding applicationsLeicester-based Taylor Hobson is a ‘globally renowned’ technology company operating at the highest levels of accuracy within the field of surface and form metrology. As part of the Ultra Precision Technologies Division of Ametek Inc, the business provides contact and non-contact measurement solutions for the most demanding of applications.

Taylor Hobson’s advanced grinding capabilities enable the manufacture of the company’s components with ‘industry-leading’ surface finish, straightness and form standards. In addition, the business’s production staff have developed a range of techniques that ‘push the boundaries’ of ultra-precision grinding.

To support its activities, Taylor Hobson’s grinding department uses a wide range of grinding technologies sourced from a variety of machine tool manufacturers, the latest addition being an Okamoto 208 ACC-CHiQ — a double-column, surface- and profile-grinding machine from Lutterworth-based DF Precision Machinery Ltd.

Explaining the reasons behind the recent purchase, Taylor Hobson’s chief manufacturing engineer, Mark Bent, said: “The knowledge and skill of our grinding staff and the resulting production of ultra-precision components has enabled a virtuous circle to develop. Taylor Hobson’s ultra-precision products are designed to measure components’ surface finish and form characteristics; therefore, our in-house knowledge of all aspects of surface finish and form has allowed our grinding department to develop procedures that enable the company’s components to be ground with outstanding levels surface finish, straightness and form.

In turn, our ability to grind to the highest of standards of precision helps the company to
develop and manufacture ultra-precision metrology products that measure surface
finish and form to the very highest standards.

“Ultra-precision grinding represents one of Taylor Hobson’s strongest areas of expertise. The levels of surface-grinding precision that we regard as relatively straightforward would challenge the vast majority of global businesses; and because the straightness, flatness, and surface finish of the columns that we grind are the basis of the precision of our metrology products, we place severe demands on our grinding machines.

Therefore, when one of our surface- and profile-grinding machines began to show its age, we started a search for a large-capacity ultra-precision replacement that resulted in the Okamoto ACC-CHiQ.”

Substantial foundations

Mr Bent added: “In order to achieve the required stability and ultra-precision performance we require, our new Okamoto grinder was installed on a substantial 0.8m-thick concrete based that sat on 14 piles that reached deep into the bedrock beneath the machine. Our flatness value target across the entire working surface of the new machine was to reach a sub-2um figure. Following the machine’s installation and precise adjustments, we were delighted to achieve a flatness value of 1.2um, a result that far exceeded our ambitious target.

“Our choice of machine, the substantial foundations it was installed on, the fine-tuning of
its working surface and the skill of our staff has resulted in our ability to achieve remarkable levels of grinding flatness.

“For example, we now grind our 600mm-long columns to a straightness value of 0.5um. In addition to the precision of the Okamoto ACC-CHiQ, its speed is also enabling us to achieve the production efficiency levels we aim for.”

DF Precision Machinery says the accuracy of a double-column grinding machine depends largely on the precision of its cross-rail, and that Okamoto has developed “an ingenious cross-rail mechanism that enables minute mechanical adjustments to be made following a machine’s installation.

“This fine-tuning correction system allows extremely high degrees of flatness and straightness to be achieved along a machine’s entire working surfaces without the need for NC corrections to be made.”

As well as featuring a 22kW spindle motor, Okamoto’s ACC-CHiQ-series machines incorporate number of features designed to maximise production efficiencies. For example, dressing times have been shortened by combining upper dressing for rough dressing with tabletop dressing for finishing.

The machine’s ‘shift-plunge’ grinding cycles also make a significant contribution to reducing processing times, while the easy-to-use iQ software — accessed via the large colour touch-screen Fanuc control — makes the grinding of large workpieces a ‘straightforward process’.

The ‘smart software’ also considerably simplifies data input, as data is automatically generated by inputting basic parameters.