Masonry Magazine November 2004 Page. 25
Contrary to a popular advertising campaign, a diamond is not forever.
Diamond is well recognized as the hardest substance known to man. One would think that an operator of a sawing machine could utilize the hardness characteristics of diamond to maximum advantage (i.e., the harder the better). In practice, this is not always true. Whether the operator is cutting stone, masonry or concrete, the diamonds must wear in order to maximize the performance of the cutting tool. This article will examine the role diamond plays in cutting tools and how an operator can use analytical methods to maximize the use of the diamond cutting tools, thereby increasing productivity and maximizing tool life.
Diamond Crystals & How They Work
DIAMOND CRYSTALS can be synthetically grown in a wide variety of qualities, shapes, toughness and sizes (Figure 1). Synthetic diamond has replaced natural diamond in virtually all construction applications because of this ability to tailor-make the diamond for the specific application.
A diamond saw blade is composed of a circular steel disk with individual segments or a continuous rim containing the diamond attached to the outer perimeter of the blade (Figure 2). The diamonds are held in place by a metal bond matrix, which is a specially formulated mixture of metal bond powders and diamond that has been pressed and heated in a sintering press. The exposed diamonds on the surface of the segment do the cutting. A diamond blade cuts in a manner similar to how sandpaper cuts wood. As the blade cuts, bond tails are formed that trail behind each diamond (Figure 3). This bond tail provides mechanical support for the diamond crystal. As the blade rotates, the diamonds chip away at the material being cut.
Contrary to a popular advertising campaign, a diamond is not forever. The exposed diamond cutting points eventually wear away, and if not for some provision to replace these cutting points, the blade or bit would soon be useless. This process is actually desired as it provides a new layer of diamond crystals to continue the cutting action (Figure 4).
Blade Operating Speeds
MANUFACTURERS PRODUCE blades for specific applications. They recommend operating speeds or a maximum operating speed for that blade and print this information directly on the blade. Recommended operating speeds are based on blade size, equipment type and the type of mate-