Educational Section

Table of Contents

Diamond Blade Basics
Diamond Tools & Technology
Factors that Affect Cutting Performance
Diamonds - Key to Successful Cutting
Cutting Depth Chart
Operating Speed Chart
Do's and Dont's

Diamond Blade Basics

Diamond tools don't really "cut" like a knife... they grind. Envision trying to saw through a 2 x 4 using your hand wrapped in sandpaper, this is how diamond blades cut.

During the manufacturing "break-in" (grinding) process, individual diamond crystals are exposed on the outside edge and sides of the diamond segments or rim. These exposed surface diamonds do the grinding work. The metal matrix, or bond, locks each diamond in place. Trailing behind each exposed diamond is a "bond tail" (also called "comet tail"), which helps support the diamond. Nothing known to man sticks to diamond (i.e. acts as an adhesive) therefore, in the sawing application, the metal bond surrounds the diamond and locks it into place by a mechanical lock or hold.

The primary function of the metal bond is to lock the diamond in place and support it under load. It is important to note that due to the shape of diamond crystals, one-half of all the diamond put into a segment is thrown away. A simplified diamond crystal shape is shown hi Fig 4. As you can see, once the surrounding metal wears to the point that is equal to or below the "equator" of the diamond crystal, the crystal will pop out. This is like trying to hold the end of a flat- blade screwdriver after dipping it into oil. The harder you grip the screwdriver the more it wants to slip out from between your fingers. To better utilize the diamond crystals in a segment the metal bond is designed to develop bond tails. This extra metal holds the diamond crystal in the metal bond longer and is the reason that bond tail development in a cutting segment is so important for blade performance.

While the blade rotates on the arbor shaft of the saw, the operator or saw pushes the blade into the material. The blade begins to cut through the material, while the material begins wearing away the blade.

Exposed, surface diamonds score the material, grinding it into a fine powder. Embedded diamonds remain beneath the bond surface.
Exposed diamonds crack or fracture as they cut, breaking down into even smaller pieces. Hard, dense materials cause the diamonds to fracture even faster. The material also begins to wear away the metal matrix through abrasion. Highly abrasive materials will cause the matrix to wear faster.

This grinding and wearing process continues until the blade is worn out. Sometimes, a small, unusable part of the segments or rim may remain. It is important to understand that the diamond blade and the material must work together (or interact) for the blade to cut effectively.

In order for a diamond blade to work properly, the diamond type, quality, and grit size must be suited for the saw and the material. The metal matrix or bond must also be "matched" to the material.

Tools for cutting hard, dense (less abrasive) materials (such as tile, hard brick, stone or hard-cured concrete) require a softer metal matrix. The softer metal matrix wears faster, replacing worn-out diamonds fast enough for the blade to keep cutting.

Tools for cutting soft, abrasive materials (such as block, green concrete or asphalt) must have a hard metal matrix to resist abrasion and 'hold' the diamonds longer.