How Diamond Blades Are Made and How They Work

Sintered metal-bonded diamond blades are the most widely used type. These blades feature a steel core, which is made from a steel plate, unlike the wire material used in diamond wire saws. The diamond segments are created by mixing synthetic diamond crystals with metal powder and then sintering the mixture. Before selecting the appropriate diamond blade for circular saw, it's beneficial to understand how these blades are constructed and how they function. This knowledge will contribute to a more efficient and successful experience on your jobsite.

How are Diamond Blades Made?

A diamond blade consists of two primary components: the steel core and the segment.

1. Steel Core: The Support Structure

The core of the blade is typically a flat, round metal disc that acts as a foundation for the outer segments. The diamonds are attached to this core through methods such as vacuum brazing, sintering, or laser welding.

• Vacuum Brazed or Sintered Attachment

Blades that are manufactured with vacuum brazing or sintering are typically more affordable and suited for high-volume production. These types of blades are intended for dry cutting soft materials using low horsepower equipment. The cores of these blades are often simpler and do not undergo as many intricate manufacturing steps as blades designed for more demanding tasks.

• Laser Welded Attachment

The method that provides the strongest bond between the segments and the core is laser welding. Norton is a pioneer in this technique and continues to perfect it. Blades designed for more aggressive tasks, such as wet cutting hard materials using higher horsepower equipment, feature thicker, heat-treated, precision-ground, and tensioned cores. These additional processes help the core resist the flexing and stress produced by heavier equipment and greater horsepower. Additionally, precision grinding reduces drag, and tensioning ensures the blade remains flat at specific rotational speeds.

2. Segment: The Cutting Component

The segment of a diamond blade is composed of two elements: diamonds and a metal bonding material.

A. Diamond Crystals (Cutting)

Unlike natural diamonds, the diamonds used in these blades are synthetic. The benefit of using synthetic diamonds is that their size, shape, and strength can be precisely controlled during manufacturing. This control allows for predictable cutting speeds, blade life, and consistent performance. When considering diamonds for the segments, it's important to evaluate:

• The amount of diamond in the segment
• The quality of the diamond
• The size of the diamond

• Amount of Diamond

The quantity of diamond in the segment can vary and directly influences the horsepower required to use the blade effectively. In simple terms, more diamonds in the segment demand higher horsepower to operate the blade. For higher horsepower saws, the blade typically contains more diamonds.

• Quality of the Diamond

Diamonds that are of higher quality can maintain a sharp point at higher temperatures and resist heat better. This ability to retain their sharpness for longer periods improves the blade's lifespan and performance in tough cutting conditions.

• Size of the Diamond

The size of the diamond is measured in mesh ranges such as 25-35 or 50-60, with higher numbers corresponding to finer particles. Finer diamonds are used for cutting extremely hard materials like quartz or chert, while larger, coarser diamonds are preferred for softer materials like asphalt or clay bricks.

Related read: Diamond Saw Blade Composition: Industrial Diamond vs Synthetic Diamond

B. Bonding System (Wears)

The bond is made from a combination of metal powders and is designed to achieve specific wear rates. The bond holds the diamonds in place, ensuring they remain functional for as long as possible before being released to expose fresh diamonds.

The wear resistance of the metal bond is crucial. Softer metals like bronze are used in soft bonds, which are common in cutting hard but less abrasive materials, such as porcelain. Harder metals like tungsten carbide are used in hard bonds for cutting softer, more abrasive materials like asphalt or concrete. An easy way to remember which bond to use for which material is that "hard bonds are for soft, abrasive materials, while soft bonds are for hard, less abrasive materials."

In some cases, you can determine the hardness of the bond by looking at the color of the segment. Soft blades used for hard materials typically have a yellowish tint due to their high bronze content.

How Do Diamond Blades Work?

Diamond blades do not actually "cut" material; instead, they grind it. The exposed diamond crystals do the grinding, while the metal matrix or bond holds the diamonds in place. Each diamond is supported by a “bond tail,” which helps maintain its position as the blade spins. As the blade rotates, the diamonds grind the material into fine particles.

After thousands of passes through the material, the exposed diamonds begin to crack and break. At the same time, the metal matrix that holds the diamonds starts to wear down.

Eventually, the diamond breaks down completely, and its fragments are carried away along with the material being ground.

As the diamond wears away, the bond material erodes in a controlled manner, gradually exposing new sharp diamonds. This continuous cycle of erosion and diamond exposure continues until the cutting section of the segment is completely used up. Once this happens, the blade is no longer able to grind the material effectively, signaling that it is time to replace the blade. 

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Frequently Asked Questions (FAQ)

• How often should I replace my diamond blade?

You should replace your diamond blade when it starts showing signs of wear, such as when it struggles to cut efficiently, produces rough cuts, or has significantly reduced performance.

• Can I use a diamond blade on all materials?

While diamond blades are versatile, they are optimized for specific materials. It's important to choose a blade that is suited for the type of material you plan to cut.

• What causes diamond blades to wear out over time?

Diamond blades wear down as the exposed diamonds fracture and break, and the metal bond erodes. The rate of wear depends on the hardness of the material being cut and the type of blade.

• Can diamond blades be sharpened?

While traditional sharpening methods don't work on diamond blades, they can be refreshed using a dressing tool that exposes fresh diamond particles for improved cutting efficiency.

• How do I choose the right diamond blade for my cutting task?

When selecting a diamond blade, consider factors like the material you're cutting, whether you're using wet or dry cutting methods, the required cutting depth, and the horsepower of your saw. Each blade is optimized for different cutting conditions.