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Precision in everything

Renishaw are long-standing pioneers in the field of innovative engineering – and there’s no doubt that the dental industry is benefiting from that level of quality expertise.

Having established themselves as a leading provider of in-lab scanning systems in recent years, the company now offers a complete solution direct to dental laboratories through its scanner and milling machine. With the additional option of central machining, labs of all sizes can select a cost-effective CAD/CAM solution that suits their particular business. In short, Renishaw are meeting the challenge of bringing simplicity and affordability to dental CAD/CAM.

‘We’re also investing £1m in additive manufacturing facilities over the next year – we see it as a key part of our future dental business,’ says Gareth Tomkinson, sales and marketing manager at Renishaw. ‘By investing in the future, you secure your future.’

The DS10 contact scanner is, the company believes, the most accurate dental scanner on the market, while at the recent International Dental Show (IDS) in Cologne they launched the DS20, a non-contact optical scanner, both of which benefit from Renishaw’s renowned cutting-edge engineering technology, focusing on precision at every stage of development.

But to understand more about how this company rose to become a major global blue chip player, we must go back. . .

HistoryRenishaw was established in 1973 by Sir David McMurtry, who remains the company’s chairman and chief executive, and John Deer, now deputy chairman.

Whether they are helping to make accurate Formula One engines, aircraft blades or dental CAD/CAM systems, enhanced precision is at the heart of everything Renishaw does – with the majority of its products manufactured in the UK. Paul Gadsby visits their Gloucestershire headquarters to report on a rather unique British success story. . .

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Their first product, the touch-trigger probe, was invented by Sir David to solve a specific inspection requirement for the Olympus engines used on the supersonic Concorde aircraft. This

innovative product led to a revolution in three-dimensional co-ordinate measurement, enabling the accurate measurement of machined components and finished assemblies.

The Renishaw DS10 CAD/CAM scanner – high accuracy ‘contact’ measurement

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Since then Renishaw have made a big commitment to research and development (R&D), with historically between 14 and 17% of their annual turnover invested in R&D and engineering. ‘For an engineering company, that’s significant,’ Gareth points out.

This commitment has enabled the company to diversify into several areas of mechanical expertise where leading manufacturers around the world can now rely on Renishaw technologies.

The majority of this R&D and manufacturing is carried out in the UK, primarily at its five sites in Gloucestershire, including their headquarters on the site of a former 19th century mill used to manufacture woollen cloth. The company also have assembly facilities located near to Dublin, and in Pune, India. In 2011 they acquired the former Bosch manufacturing facility at Miskin, near Cardiff, with manufacturing commencing there in May 2012.

Over the last 40 years the company has built up a strong global presence and now has more than 60 offices in 32 countries. They have also won numerous awards including an impressive 16 Queen’s Awards, recognising Technological Achievement, Export Achievement and Enterprise (Innovation) – ‘They are a bit like the Grammys but for UK business’ Gareth explains. ‘No other company in the UK has that many.’

Core business includes:• CMM metrology. Renishaw make probes that go into a large percentage of the global production coordinate measuring machines.• On-machine measurement. Machine tool mounted probes used to perform auto-mated setting operations, in-cycle gauging and verification of machined part dimen-sions.• Position feedback systems. Used to ensure accurate motion control on a wide range of systems, including telescopes and industrial printers.• Machine calibration. High-tech sensors used to verify machine performance, including checks for wear and tear damage.• Raman spectroscopy. Microscopes used for spectral analysis of materials, such as

paints, drugs and zirconia.• Neurosurgery. Working with leading hospitals around the world, Renishaw make medical devices for neurosurgical applications, including digital software that helps surgeons to plan procedures to implant electrodes into the brain to treat serious Central Nervous System diseases such as Parkinson’s.

Dental offeringsThe aforementioned DS10 contact scanner has an unrivalled standard of accuracy. Based on an innovative but well-proven mechanism, it provides exceptional accuracy in a compact, lightweight package. It achieves its impressive accuracy through the use of Renishaw’s contact scanning technology that has been used in thousands of measurement applications throughout the world, including aerospace engine parts.

Renishaw’s scanners and milling machines use a patented non-cartesian mechanism that, unlike conventional designs, provides a lightweight and cost-effective structure that enables high-speed processing in a compact device. So small labs can accommodate a scanner while the bigger labs can offer a full-scale CAD/CAM service from a single workbench.

The milling machine can fit easily on to a bench top and can typically mill 15 up to 30 ceramic frameworks from a single billet of zirconia, including bridges of up to eight units. With an average cutting time of 30 minutes per unit, a single milling machine is sufficient to meet the needs of most laboratories.

Renishaw supply their own zirconia billets for use with the machine, while the company’s own central manufacturing facility in Gloucestershire features large cells of the milling machines, enabling a rapid response to demand from labs that do not own a milling machine themselves, or who need overflow capacity.

Renishaw also supply a sintering furnace which can reach temperatures of up to 1,600 degrees centigrade to fire pre-sintered zirconia frameworks.

Through its own experience of CAD within the engineering field, Renishaw have, in consultation with some highly experienced dental laboratories, created an efficient and intuitive software tool that simplifies dental framework design. The software features include:• intelligent margin line placement with sketching and ‘nudge’ tools that put the user in control• Fast coping design with controllable

The Gloucestershire-based zirconia milling facilities

price as there is no precious metal content and it’s all done with CAD/CAM so it achieves a better first fit, therefore, there’s less ‘chair time’, it’s highly biocompatible (no nickel*), the process uses a more consistent material and they’re manufactured entirely in the UK.

‘We also know all the materials involved in the process – full traceability and manufactured from a UK-based company is something we’re very proud of.’

The process works by focusing a high-powered laser beam on to a bed of powdered metal (CE-marked cobalt chrome) and the selected areas fuse into a thin solid layer. A second layer of powder is then spread over the first before the laser creates the next ‘slice’ of each framework. When all layers are completed, larger frameworks are stress relieved and any implant interfaces are machined.

The advantages of using cobalt chrome are the ability to fashion a screw-retained crown by simply adding porcelain, and easy re-polishing.

‘Additive manufacturing has both cost and price benefits in dentistry,’ concludes Gareth. ‘Laser bridges and abutments come at a lower price than conventional custom abutments, giving labs cost savings they can offer to their dentists.

‘Laser-melted products are one of the fastest growing areas of our business – hence why we’re investing £1m into it.’

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Judging by the company’s past record, it’s fair to say they can embrace the future with confidence.

*In accordance with the manufacturer’s reported nickel content and permitted deviation BS EN ISO 22674:2006.

thickness and cement space• Automatic pontic and connector generation, with full configuration and customisation• Visual bite index review to assess porcelain clearance• Sectioning and measuring tools to check material thickness and cement space• Strength calculation that highlights problem areas before you commit to machining.

Once the frameworks are designed, the manufacturing data is sent either to Renishaw’s central facility or to the lab’s own milling machine. Renishaw’s milling machine is supplied with CAM which automatically converts the design into a series of cutter paths needed to machine the framework. All the lab has to do is identify where on the billet machining is to take place.

Laser meltingEighty per cent of the UK’s crown and bridge restorations are PFM (porcelain-fused-to-metal), their popularity rising in the recession due to the rising price of gold and the expense of all-ceramic options. For the last two-to-three years Renishaw have been specialising in using a laser melting process to create their own crowns and bridges, more recently creating implant-supported abutments and bridges (Renishaw now has its own Additive Manufacturing Division designing and supplying laser melting machines).

‘The laser-melting additive process consumes less energy than machining,’ says Gareth. ‘Plus the costs don’t rise in comparison to the complexity of the job.

Dentists are choosing laser-melted frameworks because they come at a fixed

Renishaw factfile• £332m annual turnover (year ending 30 June 2012)• 94% of sales exported outside of UK• £48m spend on R&D and engineering (14% of turnover)• More than 3,000 staff operating in 32 countries• 16 Queen’s Awards

For more information about Renishaw, call 01453 524524, email uk@renishaw.com or visit www.renishaw.com

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Porcelain applied directly to LaserAbutments DS10 high accuracy ‘contact’ scanner

A rendered 3D CAD image of a three-unit bridge

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