Understanding diamond saw blades is the key to realizing their value
When building structures must withstand the toughest elements, most tradespeople use concrete because it is versatile, durable and economical. Concrete can be easily shaped and colored, and it is one of the safest building materials available.
Concrete construction has been common practice since the Roman Empire. A testament to the strength of the concrete, the stadium is still standing today, but it also took eight years to build. Today, concrete remains one of the world's leading building materials, but structures had to be completed within tight schedules and budgets.
When dealing with something so strong and durable, it's also important that craftsmen are equipped with the best tools to make their jobs as easy, efficient and safe as possible.
Whether sawing shrinkage joints, cutting decorative paving stones, or making precision cuts in existing concrete, a quality saw blade is a must. Diamond saw blades offer distinct advantages over abrasive wheels when it comes to clean, professional cuts in concrete.
Nuts and Bolts – Typical Components of a Diamond Saw Blade
There are four typical components in a diamond saw blade:
Diamond crystals are usually synthetic rather than natural, allowing manufacturers to control shape and size. The synthesis process also allows the design of crystals for specific applications. Cutting performance depends on the type, shape and size of these diamond crystals.
The diamond crystals are held in place by a formulated mixture of various metals that determine the rate at which the diamond crystals are exposed. Harder binders reduce diamond erosion and are designed for softer applications such as raw concrete or asphalt. Softer bonds increase diamond erosion and are better suited for harder materials such as granite or cured concrete.
The diamond crystals and bonding matrix are heated, shaped and attached to the blade core. The edge can have one of three configurations: segmented, continuous edge, or jagged. In each case, the diamond edge is wider than the core of the blade to reduce drag on the blade itself, increase material waste removal, and reduce the chance of the blade binding in the material. These edges are fixed to the steel core by brazing, sintering or laser welding processes.
The core of the blade is made of heat-treated high-alloy steel. The core is tensioned so that the blade turns correctly over the arbor hole, which is perfectly centered in the core. The core is also tensioned or adjusted to reduce the stresses from high centripetal forces and impacts caused by cutting this dense material.
Unlike most other blades, diamond blades do not cut through material. Instead, they use the friction created between the diamond-bonded substrate and the material being cut to work like a grinding wheel.
As mentioned in the metal bond explanation, harder materials cut better when the bond is softer. As the diamond grains dull and break, the bonds are released, exposing more of the synthetic diamond. The opposite is true for cutting softer materials. The bond is stronger to ensure the diamond is exposed long enough to be fully utilized.
Cutting Types of Diamond Blades
There are two main methods of diamond blade cutting, wet cutting and dry cutting. As with all blades, one factor that significantly affects blade performance is heat – this can lead to blade loss, core warping and cracking, and the need for new blades.
This is why most diamond saw blades utilize water to dissipate heat and prolong blade life. In addition, water helps prevent dangerous dust containing silica when cutting concrete. OSHA has a number of regulations that limit the amount of dust that can be generated when cutting.
Dry cutting is used less frequently and is usually used for small jobs such as cutting paving stones, and should only be done outdoors. According to diamond blade manufacturer MK Morse, "Dry cutting blades require sufficient airflow around the blade to keep the steel core from overheating. This is best accomplished by making shallow, intermittent cuts through the material with a few seconds of 'free Rotation" to maximize the cooling process.
The main difference is how the diamond matrix is attached to the core. Wet blades are brazed, while dry blades are usually laser welded. Laser welding has a higher melting point. Besides welding, another difference is bonding. Dry blades usually have a slightly softer binder to allow for easier cutting without water to cool and lubricate the cut.
Segmented diamond saw blades vs. continuous rim saw blades
We added this section to the article after a reader asked when to use segmented versus continuous edge blades. The answer is that it depends on many variables, including the material being cut, cutting speed, surface quality and water availability. Segmented blades are typically used in dry cutting operations. Each segment is separated by a slot or slots.
These areas have important functions of dissipating heat and removing debris. As a result, you will often see faster cutting speeds as well. Continuous edge blades are wet cutting blades that run very slowly (relatively speaking) but cut the cleanest. This is very important when working with very brittle materials or when cutting edges will be exposed. Both blades are suitable for cutting concrete, masonry, paving stones and more.
Using Diamond Blades on Steel
Another consideration is when using diamond blades in concrete. Rebar is the backbone of concrete structures and the bane of drill bits and blades. If cutting rebar in exposed conditions, a diamond blade will finish the cut quickly, but will greatly reduce the life of the blade. This is because diamond blades "cut" by abrading the material, rather than tearing and tearing other blades. When cutting concrete where you're sure to find rebar, it's usually best to use a continuous edge blade with a water supply.
Diamond saw blades come in a variety of sizes, from 4 inches for angle grinders to 36 inches. Think of the walk saws you see when crews cut roads or sidewalks – they use diamond blades.
Diamond blades are very expensive compared to grinding wheels. While the initial cost is enough to scare off some buyers, it's the cost per cut that matters. Grinding wheels have a short lifespan and are not as effective at cutting harder materials. Users use 50 times more abrasive than diamond saw blades.
Since the price of diamond saw blades varies widely, you must consider the value they bring to the contractor. Kias and Porsches are cars, but the Rio sells for less than $20,000, while the Cayman retails for more than $85,000. A Porsche can also get you to the finish line of a track faster. I'm not trying to be glib, but this is fairly similar to the differences between current offerings on the market. The companies that invest in new technology, use the highest quality steel and add the highest concentration of diamonds provide blades that cut better and last longer.
When shopping for tools, drills or blades I consider each new addition and my mindset is to get the best I can afford which will get the job done with the best results and the least amount of effort. Time is money, but money is also money.
In the end, diamond saw blades are an extremely effective tool for reducing work time with even the toughest materials, and because they have a long shelf life, the initial investment will eventually pay off when used properly.
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