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Contour Satisfies the Stringent Demands of Spectacle Lens Manufacturers The proliferation of advanced High-Index Polymer spectacle lens materials and the evolution of manufacturing techniques to generate ‘Progressive’ Multi-Focal lens geometries, has lead Contour to refine its diamond tool offering for this hugely dynamic industry. With manufacturers striving to reduce cost by reducing post-polishing requirements and increasing yields, Contour has established itself as playing a vital part in both criteria. With customers statistically analysing ’Lenses per Edge’ ratio and other critical performance paramaters, Contour has developed both naturaland synthetic diamond tool solutions, with various insert style mounting strategies. Modern spectacle lens manufacturing processes make use of diamond machining processes not dissimilar to those that Contour has applied itself to for decades, yet the machine developments now allow for a wide range of surfaces to be generated, from spheres and aspherics, to torics and true freeforms. Despite this large variation in requirements, Contour is able to provide a near-universal tool geometry to allow for most Prescriptions to be fulfilled, thus providing further flexibility. Typically featuring a relatively large tool radius of around 2mm with a conical clearance, the increased diamond size contributes toward improved surface texture and tool life, with efficient heat dispersion and a super-strong bond to the insert. Contour is able to offer valuable recommendations to customers depending on the machine type being used and the materials being processed, while Club CFT provides a particularly useful portal to allow tool history to be tracked and provide access to other tool data. _
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February 2011
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Optimize Your Investment It is an unavoidable fact that the more a diamond tool is worn, or even damaged by the machining operation, the more material diamond needs to removed during the relap process, thus reducing diamond thickness and ultimately the life of the tool. For example and from a relative perspective only, if a more costly controlled waviness tool is used for a finishing operation on a Germanium lens, around 15 relaps could be possible before the diamond is too thin for further use. Compare this to a lesser cost non-controlled waviness tool used for a roughing operation, and the number of relaps might be halved. The more aggressive wear characteristics (as shown immediately below) of the roughing process simply require more diamond to be removed to return the cutting edge to an ‘as new’ condition’.
Of course a lightly worn controlled waviness tool (as shown below) could be relegated to the role of a roughing tool, however this potentially can prove to be a false economy as the tool wears more aggressively.
Tool change and set-up time needs to be considered, which can offset the disadvantages the additional wear brings, but Contour makes the general recommendation that its controlled waviness tools are used for finishing processes only, to minimize tool wear and ultimately maximize tool life - Maximizing Your Investment. |
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Employee Spotlight - Suzanna Heylen
Taking responsibility for the selection of the rough diamonds for both Technodiamant’s Belgium and Dutch operations, Suzanna makes regular trips to Europes ‘Diamond Capital’ of Antwerp to carefully select only those stones that are most suitable for its products. With a keen eye on costs, Suzanna follows all aspects of production to ensure that all facts and figures are presented for regular management accounting. When not working, Suzanna enjoys spending time with her two grandchildren. To get away from it all, a few weeks camping in the south of France is her favorite way to spend the holidays. |
With almost 30 years in the Diamond business, Suzanna is one of Technodiamants true ‘Gem’ employees.