Control of diamond quality for tool manufacture
While the diamond used in the manufacture of any diamond tool is of vital importance to the performance of the tool, toolmakers rely on the diamond producers for consistency of (diamond) raw material. Threrefore, while the toolmaker may have control over the metal or resin matrix used in the tool, the most the critical component, the diamond, is controlled by a third party, namely the diamond producer / supplier.
Diamond quality is controlled through diamond processing which involves control of diamond size, shape and metal inclusion content. The diamond source (i.e. the manufacturer) also was a major factor. However, as most diamond producers now have a good handle on the synthesis process and the diamond sources are less of a factor providing that the processing operation is well established and controlled. Also, diamond processors usually purchase and combine diamond from a range of diamond synthesisers for their diamond processing operation.
The primary diamond structures (namely size, shape and metal content) determine the diamond properties like strength (friability) and thermal stability, which in turn determine the performance of the diamond in the tool application. These diamond properties and performance characteristics, by the very nature of the material, are notoriosly difficult to measure. Diamond processors therefore rely on ‘indirect’ measures like strength and thermal strength to grade and control the products they supply to the market. This approach is well established and as long as diamond quality is never compromised in favour of utilisation, the end-product will remain reasonably consistent.
Fabrication companies rely on the toolmakers for the quality of the diamond tools that they purchase. However, these fabricators should never lose sight of the fact that they also are relying on the diamond suppliers for the consistency of the diamond raw material used in the tool matrix. The expectation from the fabrication companies is that the diamond is well controlled and that the toolmakers have rigorous incoming material checks. However as mentioned, toolmakers rely mainly on the diamond producers for material control due to the difficulties of measuring diamond properties.
If tool price is the driving factor and the toolmakers are focus on providing the cheapest possible products to the market they are likely to use the cheapest diamond products available. Diamond processing and quality control is costly and therefore lower cost is likely to mean lower quality (control). Lower quality control leads to increased variability in diamond property distributions and consequently, the performance of the tool may be compromised or may not be consistent from batch to batch.
Following on from the article Quality Verses Price (Calculated Tool Buying, The Choice is Yours) fabrication companies should consider the diamond raw material control when evaluating any toolmaker as a potential supplier of diamond tools.