Leicester-based Taylor Hobson is a globally renowned, ultra-precision technology company providing 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 enables the manufacture of the company’s components with industry-leading surface finish, straightness and form standards. In addition, the business’ skilled 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 boasts a wide range of cutting-edge grinding technologies sourced from some of the world’s leading machine tool manufacturers. The latest hi-tech addition to the department is an innovative Okamoto 208 ACC-CHiQ, double-column, surface and profile grinding machine.

Production of ultra-precision components
Mark Bent, chief manufacturing engineer at Taylor Hobson, said: “The knowledge and skill of our grinding staff and the resulting production of ultra-precision components has enabled a virtuous circle to develop.

“For example, 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 of surface finish, straightness and form precision.

“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.”

He continued: “Ultra-precision grinding represents one of Taylor Hobson's strongest areas of expertise. We produce the reference datums for our measuring instruments with a combination of dimensional, geometrical, straightness, flatness, and surface finish control, that are among the very best in the world. The levels of surface grinding precision that we regard as relatively straightforward would challenge the vast majority of global businesses.

“As the straightness, flatness, and surface finish of the columns that we grind represent the foundations of the precision of Taylor Hobson’s metrology products, we place severe demands on our grinding machines. Therefore, when a previously used surface and profile grinding machine began to show its age, we started a search for a large capacity, ultra-precision replacement.

“Having dismissed several options that lacked the required precision capabilities, we purchased an Okamoto ACC-CHiQ double-column machine from DF Precision Machinery Ltd.

In order to achieve the required stability and ultra-precision performance, we installed our new Okamoto grinder on a substantial 0.8 meter concrete foundation, with a further 14 piles that reached deep into the bedrock beneath the machine.

“Our challenging 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 the installation engineers’ precise adjustments, we were delighted to achieve a flatness value of just 1.2um, a result that far exceeded our ambitious target.

“Our choice of machine, the solid 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 an impressive straightness value of 0.5um. In addition to the precision of the Okamoto ACC-CHiQ, the machine’s impressive speed is also enabling us to achieve the production efficiency levels we aim for.”

High-accuracy grinding
Used throughout the world in some of the most challenging of grinding situations, Okamoto’s advanced ACC-CHiQ Series of double-column machines satisfy the demands for high-accuracy grinding while also providing the production speeds required by today’s manufacturers.

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

The company’s fine-tuning correction system allows for extremely high degrees of flatness and straightness to be achieved along machines’ entire working surfaces without the need for NC corrections to be made.

Okamoto’s ACC-CHiQ series of machines boast 22kW spindle motors that deliver the maximum horsepower in this class of machine. Complementing the advanced ACC-CHiQ series precision grinding capabilities, the machines boast a number of features that provide impressive levels of production efficiencies.

For example, dressing times have been shortened by combining upper dressing for rough dressing with tabletop dressing for finishing. Also, the machine’s shift-plunge grinding cycles make a significant contribution to reducing processing times.

The use of feature rich, yet easy to use iQ software via the large colour touch screen Fanuc control, makes the processing of large workpieces grinding a straightforward process. The smart software considerably simplifies data input and reducing cycle time. Data is automatically generated by inputting the grinding wheel's grain size, total machining allowance and precision machining allowance.

Then, by inputting the grinding wheel size the optimum grinding wheel condition is automatically created based on grinding process theory. Data input can be achieved using only two screens, whilst panel buttons cover the full range of surface grinding and grinding operations.

Traditionally grinding processes largely relied on operator’s skill and intuition. To provide maximum assistance, Okamoto has developed a function for automatically setting the recommended process conditions based on grinding process theory and Okamoto’s in-house knowledge.

iQ software supports the use of both Alundum-type grinding wheels and ultra-abrasive-coating grinding wheels. Users are also able to input their own condition settings. The software graphicly displays the position at which grinding is to be performed on screen. The cycle end time is also displayed, further saving setup time.

Mike Duignan, DF Precision Machinery director, said: “As the exclusive distributor of Okamoto Grinding Products in the UK, we were delighted to supply an advanced, Okamoto 208 ACC-CHiQ, double-column, surface and profile grinding machine for such a demanding application. Also, we were happy to assist the staff of Taylor Hobson’s staff in obtaining maximum ultra-precision performance from the high-accuracy machine.”