Earlier diamond segment of diamond circular blades was designed to be even cuboids. Later, people found that, after a period of sawing, the two sides of the segments are easier to be worn than the middle, and the segments become a convex shape. The convex-shape diamond segments have a larger contact area with the material being cut, therefore the diamonds on them are easier to be ground blunt and then need dressing. In addition, as the sawing force will also increase, the core of the diamond blade tends to be distorted and be deformed for vibrations. This can influence the cutting precision, and reduce the blade core’s service life. Sandwich diamond segments, which have higher side layers and lower middle layers, however, can solve this problem to a great extent.