Novel CVD Diamond Styli for Contact Measurement Machines Developed by Element Six
For the first time synthetic diamond spheres have been developed for use in measurement tips used in scanning co-ordinate measurement machines, CMMs. The new product is being demonstrated at the major industry exhibition, Control 2007 Sinsheim in Germany. Already several companies have expressed interest in the advantages of the new diamond technology.
The motivation for the development of diamond spheres was to overcome some of the drawback of current materials used as measuring tips. Until now measurement tips were made from hard ceramic materials like ruby, sapphire, aluminium oxide, silicon oxide. However, they experience dimensional changes to the measurement tip that lead to measuring inaccuracies caused, for example by temperature changes, material build-up and wear. Diamond styli show significantly less wear when scanning hard materials and less build-up when scanning soft materials, such as aluminium alloys, and these applications represent the greatest market area for the new styli.
Two sizes of sphere are being manufactured initially - 1mm and 3mm diameter - as these are the most common probe sizes, though other diameter sizes could be introduced in the future.
As scanning co-ordinate measurement machines are growing in importance in the manufacturing environment for in-line quality control in the automotive, aerospace and medical equipment industries, greater demands are being placed on the improved reliability and accuracy of the measurement results. These machines are widely used in manufacturing industry for the accurate measurement of complex industrial components such as motor blocks, cylinder heads and gearboxes during production.
Rigorous testing of diamond has been carried out and these results compared against the best competing materials. For measurements of material build-up when scanning aluminium components, diamond out-performed ruby by a significant margin. In practical terms, the performance of diamond spheres in scanning cmms adds up to significant advantages for users. Overall this means that diamond styli can be used to increase productivity by decreasing direct material costs and downtime as well as increasing process stability.