Diamond Blade

The core is typically a round flat metal disc used to support the outer segments. The diamond can be attached to the core using vacuum brazing, sintering, or laser welding. The process level used to manufacture the core is related to the attachment methods. Lower cost, higher volume blades use either a vacuum brazed or sintered attachment process. Vacuum brazed and sintered blades are intended for dry cutting soft material on low horsepower equipment. The cores used for these blades are typically very simple and do not undergo many of the steps of the blades for more aggressive applications.

Of the three most common forms of attaching the segments to the core, and by far the method that yields the strongest bond to the core, is laser welding. The more aggressive applications for diamond blades involve the use of higher horsepower equipment wet cutting harder materials to much greater cut depths. The steel cores for these aggressive applications are thicker, heat-treated, precision-ground, and tensioned. The additional thickness and heat treatment allows the core to withstand the flexing stress of the heavier equipment and higher horsepower. The precision grind on the surface minimizes the drag while the tensioning establishes the flatness of the blade at a specific rpm range.

The diamond used is manufactured or synthetic as opposed to natural. Manufactured diamond is preferred over natural diamond because key characteristics like crystal shape, size, and strength can be closely controlled through the manufacturing process. The ability to control the key characteristics of the synthetic diamond allow for accurate prediction of cutting speed and blade life as well as consistent repeatability. The amount of diamond in the segment is variable and requires more horsepower as the content of diamond is increased in the segment. Simply put it means that as more diamond is added to the segment more horsepower is needed to make the blade cut. In practical terms this means that blades for high horsepower saws will have more diamond in the segment.

The quality of the diamond determines the ability of the individual diamond to resist heat and maintain a sharp point. Better diamonds can hold a point longer at higher temperatures. Finally the last thing to consider is the size of the diamond. The individual’ s diamond sizes are specified in mesh ranges like 25-35 or 50-60. The higher the numbers the finer the individual particles. In practical application finer diamond is used for critically-hard material like chert or quartz while the larger more coarse diamond is used for soft materials like asphalt and soft red clay bricks. The bond is a mixture of metal powders used in various combinations to achieve specific wear rates. A correctly-formulated bond holds the diamond in place, just long enough to get maximum use from the diamond points before releasing the stone and exposing the next layer of diamond.

The wear rate for the segment can be simplified to the ability of a metal to resist wear from abrasion. Metals with low abrasion resistance like bronze are considered soft. The soft bonds are mostly made up of soft metals like Bronze and are common when cutting very hard less abrasive material like porcelain. The hard bonds are mostly made up of hard metals like tungsten carbide and are common when cutting very soft abrasive materials like asphalt or freshly poured concrete. The best way to remember bond-to-material application is ‘opposites attract’ - hard bonds for soft abrasive materials while soft bonds are used for hard less abrasive materials. In some extreme cases, it is possible to simply judge the hardness of the blade by noticing the color of the segment. Because soft blades contain a majority of Bronze, the soft blades for extremely hard materials will have a yellow tint to the segment.

Factors involving concrete
When cutting concrete, several factors influence your choice of diamond blades. These include compressive strength, hardness of the aggregate, size of the aggregate, type of sand, steel reinforcing and green or cured concrete.

Compressive strength
Concrete slabs may vary greatly in compressive strength, measured in pounds per square inch (psi). Most concrete roads are 4-6,000 psi, while typical patios or sidewalks are about 3,000 psi.

Hardness of aggregate
There are many different types of rock used as aggregate. Hardness often varies even within the same classification of rock. For example, granite varies in hardness and friability.

Size of the aggregate
The size of the aggregate affects diamond blade performance. Large aggregates tend to make a blade cut slower. Smaller aggregates tend to make a blade cut faster.

Type of sand
Sand is part of the aggregate mix, and determines the abrasiveness of concrete. "small aggregate" is usually sand. Sand can either be sharp (abrasive) or round (non-abrasive). To determine the sharpness of sand, you need to know where the sand is from. Crushed sand and bank sand are usually sharp; river sand is usually round. Green concrete is more abrasive than cured concrete. When the concrete is not fully cured sand can more easily be scraped off the surface being cut. More loose sand means more abrasiveness.

Amount of steel reinforcing (rebar)
Heavy steel reinforcing tends to make a blade cut slower, while less reinforcing tends to make a blade cut faster. "light" to "heavy" rebar is a very subjective term.

Green or cured concrete
The drying or curing time of concrete greatly affects how the material will interact with a diamond blade. Green concrete is freshly poured and has set up, but is not yet fully cured. It is softer and more abrasive than cured concrete. You need a harder bonded blade with undercut protectors to cut green concrete. You need a softer bonded blade to cut the same concrete in a cured state.

Choosing the right diamond blade depends on what you’re using it for because they come in many sizes, performance levels, qualities, and prices. So, how do you choose the right one? Typically, you want to consider the following aspects. The first thing to look for is whether the blade can cut the materials you have. While most are compatible with diamond blades, some materials like asphalt and sandstone need specifically designed diamond blades.

Next, you’ll want a blade that won’t wear down quickly but also cuts at high speeds. Being able to cut quickly means you’ll get a precise line and reduce chipping, but this can also cause your saw to overheat and wear it down over time. If you can, go for a segmented wet blade rather than a dry one. This helps keep the blade cool, which increases its lifespan.

Lastly, one of the most important things to consider is whether it’s compatible with your saw. If your saw and blade aren’t matched, this can shorten the blade’s lifespan. Generally, your equipment will perform better if you match low-performance blades with low-horsepower saws, and high-performance blades with high-horsepower saws.

A diamond blade consists of synthetic diamond crystals that are bonded to the blade’s edge. These diamonds make clean “cuts” by grinding away at the surface of the material. It’s the best choice for almost every cutting job because it’s long-lasting, produces less heat, cuts precisely, and makes minimal noise.