A question of detail? Renishaw's Cyclone scanning system has the answer

A family run business dating from 1939, MMI Group Ltd manufacture an extensive range of customised medals, awards, insignia and engraved costume accessories tailored to individual and company requirements. Dublin-based MMI's success has been largely dependant upon the dedication and determination of the various family members, relying on traditional hand made methods until the early '80s. However, the past now sits side by side with the latest technology and MMI's business growth has led to the acquisition of Renishaw's Cyclone scanning system.

It was not until 1981 that the company invested in automated blanking and automated coining presses. Throughout the 80s 'automation by degree' saw automatic polishing and electro-plating follow, but with a definite purpose. Previously relying on subcontract services, automation of the manufacturing procedure improved the quality of the product and allowed for a tighter control of the process therefor giving shorter lead times required by a global market.

Director, Enda Woods explained the process of change. "All the dies and moulds that are currently made are cut in using a very simple pantograph type die sinking machine with the finishing touches added by hand, which is good enough for certain types of medal but for badges of very high specification it does not guarantee the quality of die required. We looked at CAD packages to programme in the 3-dimensional detail required from the 2-dimensional sketches we receive. However, this proved to be a very slow process. Our badges have a multitude of different surfaces and heights with varying detail, giving rise to differing curves and angles and is not 3-Dimensional in the way you see a car bonnet. We are dealing with very small areas from 2 inch to 3 inch diameters encompassing an enormous amount of detail and this proved very difficult to programme into CAD.

From a sketch, or recreation of a design from a medal, badge etc... we have two ways of approaching the job. The CAD process as we've discussed is a slow process. The diemaker, who is a very skilled operator can make a die by hand from a 2-dimensional sketch with the third dimension added by eye and experience. That is the way that most diemakers in our industry work worldwide, never duplicating the die. However, a die can wear in time and copying a current design this way can also be a lengthy process. Our need to be able to duplicate the detail led us to look at some form of data capture. We looked at optical scanning but the cost far outweighed the benefits whereas the Renishaw Cyclone touch probe scanning system was a cost-effective option that fitted our requirements.

The Cyclone will replicate the detail on dies sometimes taking 300,000 to 400,000 reference points in a 12 inch diameter. It will also allow us to copy the designs of the past, scan existing stock, adding features or reducing features if we want to, thereby adding to a particular range. We scan in very minute detail, our products are asymmetric and there is no continuity of design from one part of a badge to another because there could be a crown required on one part, a cannon on another and so on - the Cyclone deals with this very well".

The TRACECUT digitising software, which is an integral part of the Cyclone system allows MMI to automatically produce the NC part programs to mill prototypes in wax, resin or wood. Scaled up by a factor of 10, this allows the diemaker to artistically sculpt the form/design required. The altered prototype is then scanned, reducing the data to scale whilst retaining the detail and outputting to CAD file.

MMI are currently building up a library of dies, enabling them to duplicate any design. As a result the Renishaw Cyclone is working non-stop. The data is currently being output to local toolmakers but they would like to bring that aspect of manufacture in-house, producing NC programs from TRACECUT for milling centres or EDM wire cut systems. MMI however, will approach that expansion 'by degree'.