What is the difference between the single crystal diamond (= SCD) and the sintered diamond (or poly crystal diamond = PCD)?
SCD is in itself a diamond crystal. On the other hand, PCD is made by sintering the powdered single crystal diamond under the high temperature and high pressure using the binder of e.g. Co. Generally a single crystal such as diamond has a crystal orientation. By grinding according to the orientation, the wear makes progress easily. Diamond is ground by making use of this merit. On the other hand, as the orientation of each grain that composes the diamond sintered body is irregular, making PCD micro tools by grinding work is almost impossible.
Basically a synthetic diamond is used. In case of natural diamond, the quality is not homogenous, while there exists one with an excellent quality, there exists one with defect containing impurities or crack. On the other hand, the quality of synthetic diamond is homogenous in quality making it suitable for making cutting tools, therefore, synthetic diamond is generally used, except for a limited kinds of turning tool where a natural one is used.