HELPFUL TIPS

Information About Diamond Blades
Aggregate Map
Application Chart
Trouble Shooting

Information about Diamond Blades

What is a Diamond Saw Blade?
How does a diamond saw blade work?
How to select a diamond tool
Types of diamond blade cutting

What is a diamond saw blade?

• A diamond saw blade is composed of two basic elements: the circular sheet steel and the diamond-impregnated segment. The latter may have three different forms: a segmented rim, a continuous rim or a castellated rim.



• The metal center of the segmented diamond saw blade is produced from very high quality quenched, drawn steel, with the segments separated by slots. These slots assist in cooling the blade during sawing by allowing water (wet cutting) or air (dry cutting) to flow between the segments. They also permit a certain amount of elasticity in the blade during sawing.



• Most of the steel sheet is mill-tensioned so that the blade rotates vertically straight while allowing it a certain amount of elasticity.



• The segments or diamond-impregnated rims are a mixture of diamond grains and powdered metal. The diamonds used in the manufacture of the saw blades are almost exclusively industrial diamonds of different sizes and qualities depending on the material to be cut. During the manufacturing process the metallic powder and diamond grain mixture is compressed at very high temperature to obtain a solid metal alloy (called the bond or matrix) which retains the diamond grain.



• The segment or rim is slightly wider than the steel centre of the blade. This clearance enables the leading edge to penetrate the material without engaging the steel.



• Various processes are used for fixing the segments or rims firmly to the steel:

1. Brazing: silver brazing solder is placed between the segment and the steel. The solder melts at high temperature and binds the two elements together. The same applies to drill bits and surface-grinding wheels.
2. Laser Welding: laser micro fusion enables the segment to be welded to the steel, to the drill-bit or to the body of the grinding wheel. The laser welded bond is so powerful that it enables the tool to be used for dry cutting.
3. Sintering: some metal bonding materials may be fixed to steel core by sintering. The forces of cohesion are so powerful that they bond the continuous rim to the steel

How does a diamond blade work?

A diamond saw blade does not cut but works by milling. When the tool is given its edge in the factory, the individual diamond crystals are exposed on the leading edge and the sides of the segment or rim. It is these exposed diamonds which carry out the milling.

The metal matrix holds each diamond in place. This bonding matrix is crucial to the overall performance of the diamond blade and serves several functions:

• Disperses and supports the diamonds
• Provides controlled wear while allowing diamond protrusion
• Prevents diamond “pull-out”
• Acts as a heat sink
• Distributes impact and load as the diamond attacks the cutting surface

The diamond crystals, often visible at the leading edge and sides of the rim/segment, remove material by scratching out particles of hard, dense materials, or by knocking out larger particles of loosely bonded abrasive material. This process eventually cracks or fractures the diamond particle; breaking it down into smaller pieces. As a result of this phenomenon, a diamond blade for cutting soft, abrasive material must have a hard metal matrix composition to resist this erosion long enough for the exposed diamonds to be properly utilized. Conversely, a blade for cutting a hard, non-abrasive material must have a soft bond to ensure that it will erode and expose the diamonds embedded in the matrix. These simple principles are the foundation of "controlled bond erosion".

How to Select a Diamond Blade

Blades intended for cutting hard, dense less abrasive materials (such as tiling, hard bricks, stone or old hard concrete), require a softer metal matrix. This will wear down faster, replacing the worn diamonds fairly quickly so that the blade continues to cut.

Blades intended for cutting soft, abrasive materials (like green concrete and asphalt) must have a hard, abrasion-resistant metal matrix in order to retain the diamonds for a greater length of time.

1. The Price: Decide which is most important to you: the initial price of the tool or the cost per cut. For small jobs, or occasional use, a low-priced tool may be preferable. For larger jobs or regular use, a higher-priced tool will actually be less expensive to use because it will deliver a lower cost per cut. For really big jobs, the lowest possible sawing cost is usually much more important than the initial price.
2. Wet or Dry Cutting: Choosing wet or dry may be a matter of user preference or job requirement. The use of water requires certain precautions to be taken if electrical equipment is to be used. For concrete floor saws, wet cutting is usually preferred because you can cut deeper when using water as a coolant. For tile and masonry saws, either wet or dry cutting tools can be used. For high-speed cut-off saws, dry tools are more popular, but they are often used wet to control dust. Wet tools and bits MUST be used with water. Dry cutting tools may be used either dry or wet, as the job or equipment allows.
3. The Material to be Cut: Correctly identifying the material you are going to cut is the most important factor in choosing a tool. It directly affects the cutting speed and the life of the tool. You will find diamond tool application recommendations throughout the catalogue to help you select the correct tool for the job. Most tools cut a range of materials. For maximum performance (cutting speed AND life), the tool specification must be matched as closely as possible to the material which will be cut most often, or the material for which top tool performance is most important.
4. Additional Useful Information: The diamond segment height: Diamond tool segment height by itself is not a true measure of a tool's value. Many other factors also affect the performance of the tool; you should also consider the diamond size, concentration and quality, the hardness of the bond, the cutting power (torque) of the equipment; the segment and slot geometry of the steel centre, and how well the blade specification is matched to the material being cut.
5. Which type of rim to choose: A continuous smooth rim provides the smoothest cut in ceramic tiles and ornamental stone. Continuous castellated rim blades or super-jointed segments may produce slight chipping but generally have a longer life and lower cost per cut than continuous rim blades. Segmented blades provide the longest life and lowest cost per cut but are only suitable for work where chipping is not a problem.

Types of Diamond Blade Cutting

There are two basic types of cutting-Dry or Wet. The choice of which type of blade to use depends on:

• The requirements of the job
• The machine/tool utilizing the diamond blade
• The preference of the operator

In the case of dry cutting, the overwhelming popularity and quantity of hand-held saws and the flexible nature of Diamond blades to professionally handle most ceramic, masonry, stone and concrete materials, make the dry cutting blade a very attractive tool.

When using a dry blade, the user must be aware of distinct operating practices to ensure optimum performance. dry cutting blades require sufficient airflow about the blade to prevent overheating of the steel core. This is best accomplished by shallow, intermittent cuts of the material along with periods of "free-spinning" for several seconds to maximize the cooling process.

During wet cutting operations, liberal amounts of water act as a coolant to support the cutting effectiveness and longevity of the wet blade. Additionally, using water adds to the overall safety of cutting operations by keeping the dust signature down.

Concrete

Four essentials about concrete to help determine proper diamond blade selection.

1. Compressive Strength

The hardness of concrete is referenced by its compressive strength measured in Pounds per Square Inch (PSI). Cured concrete slabs vary widely in compressive strength; with moisture, temperature, design of mixture additives, cement materials and curing processes often determining their measured level of strength. The higher the compressive strength, the harder the material.

2. Age of the Concrete

The "age”, or length of curing time greatly affects how the diamond blade interacts with the concrete. Although methods exist to accelerate the curing process, the "state" of concrete from initial pouring to a period of 72 hours and over can be defined in 3 distinct increments, and is influenced by temperature, weather, moisture, aggregate, time of year, admixtures and composition.

State 1

The concrete is considered in its "green" state 0 to 8 hours after the pour, meaning it has set but has not hardened completely. With green concrete, the sand in the mixture has not bonded to the mortar blend firmly and will cause extreme abrasive action once the physics of sawing begins. Further, the slurry generated by green concrete is equally as abrasive and will require special undercutting protection for the steel core of the diamond blade. Typically, sawing control joints of highways, industrial flooring, driveways, runways and like-projects is performed during this state.

State 2

The concrete is considered as cured 8 to 24 hours after the pour. The sand is held firmly adhered to the overall mixture. Generally, control joints established in State 1 are widened during this time.

State 3

The concrete is considered as cured 24 to 72 hours after the pour. The sand is held firmly in the mortar mixture and the overall abrasive actions and properties of the concrete is greatly diminished. Now, consideration of the aggregates, compression strength and steel content of the concrete becomes important factors in determining proper diamond blade selection. 3. Aggregates and Sand Aggregates are the granular fillers in cement that can occupy as much as 60% to 75% of the total volume. They influence the way both green and cured concrete perform. Aggregates can be naturally occurring minerals, sand and gravel, crushed stone or manufactured sand. The most desirable aggregates used in concrete are triangular or square in shape; with hard, dense, well graded and durable properties. The average size and composition of aggregates greatly influence the cutting characteristics and selection of the diamond blade. Large aggregates tend to cause blades to cut slower, and smaller aggregates allow the blades to cut faster.

Aggregate hardness is referenced by the Mohs Scale. This scale assigns arbitrary quantitative units, ranging from 1 through 10, by which the scratch hardness of a mineral is determined; each unit of hardness is represented by a mineral that can scratch any other mineral having a "lower-ranking" number. The minerals are ranked from talc or 1 (the softest), upward through diamond or 10 (the hardest). Hard aggregates shorten blade life and reduce cutting speed.

Sand composition is another factor in determining the hardness characteristics of the cement and the abrasive properties of the mortar. Three types of sand are generally used in the mixture:

• River Sand (round non-abrasive)
• River Bank Sand (sharp abrasive)
• Manufactured Sand (sharp abrasive)

River Bank Sand and Manufactured Sand are more abrasive than River Sand. The more abrasive the sand is, the harder the bond matrix requirements. Also, sharper; more geometrically defined sands require harder bonds.

4. Steel Reinforcement

Further strengthening and structural integrity of concrete is accomplished by introducing concrete Reinforcing Steel Bars (Rebar), Steel Wire Strand of Wire Meshing into the concrete. It costs more to cut concrete that contains reinforcing steel because cutting rates are slower and blade life is reduced. If the cross-sectional area of concrete is 1% steel, the blade life will be about 25% shorter than if no steel were present. Concrete with 3% steel can reduce blade life as much as 75%.

What You Should Know About Asphalt

Hot Mix Asphalt (HMA) is a mixture of Asphalt Cement (a petroleum based "glue" that comprises less than 8%, by weight, the total pavement mixture) and Aggregates (various sized stones, dust, hard inert materials and sand; comprising approximately 92%, by weight, the remaining pavement mixture.) Asphalt does not cure in the sense that concrete does, and once spread and rolled, it can be cut or drilled almost immediately. Unlike cured concrete, sand in asphalt never bonds as firmly, and the slurry created when sawing will be extremely abrasive. A bond matrix similar to cutting green concrete and undercutting protection steel cores are important factors when undertaking asphalt cutting operations. Some unique factors should be observed when cutting asphalt:

• Hard & large sized Aggregates in the asphalt will cause the blade to cut slower.
• The greater the Aggregate-Sand ratio, the faster the blade will cut, but total footage may decrease.
• Total asphalt depth can vary. It is common to cut through the asphalt layer into the sub-base. Generally, the sub-base contains a high content of very abrasive materials such as sand, dirt, dusts and like-materials. This undesirable situation causes rapid wear of the diamond blade.
• Chunks or broken up asphalt to be cut often attracts dirt and sand fillers within the cracks. This, too, will make the asphalt more abrasive and affect the life of the diamond blade.

What You Should Know About Ceramic

Tile Ceramic products are varied and depending on their manufacturing processes's, they exhibit their own special qualities and properties. The hardness of the ceramic material is directly attributed to its manufacturing process, and generally references the Mohs Scale to categorize its hardness.

The Manufacturing Process

Ceramic tile production begins with the excavation of clays to be used in the manufacturing process. Depending on the type of tile being produced, any number of two to six different types and colors of clay may be necessary to blend together in a mixture.

The selected bulk clays are mixed with water and this mixture is pumped into large, rotating cylindrical mills, where extreme grinding action pulverizes the clay into uniform and homogenous particles. This substrate is called "body-slip", and has the consistency of a milk shake.

Next, moisture from the body-slip is evaporated by a spray dryer burner; creating fine particles of uniformly sized dry clay called "powder". The powder is then fed into molds within a hydraulic press, where it is molded into pressures of approximately 4,000 PSI to form "green ware" (what the tile is called prior to being fired). The green ware is dried again to further reduce the moisture content, and then travels down "glaze lines' where various types of glazes are applied to the surface.

The glazed green ware travels through a kiln and undergoes a 45-50 minute firing where temperatures can reach 2300°F causing the glaze to fuse to the body. The tile that emerges from this process is very hard, durable and impact resistant.

Hardness of Ceramic Tiles

• Water absorption rate, glazes, compression and material all determine the hardness of ceramic tile.
• The percentage of water absorption by the tile body determines whether the ceramic tile is Impervious, Vitreous, Semi-Vitreous, or Non-Vitreous. From Impervious, where absorption rates of 15% and higher, harness factors change.
• Most glazes fall in the 5 to b Mobs Scale range. However, certain types of floor and porcelain tiles can have compressive strengths of 10,000 PSI and a Mobs hardness factor of 8.

What You Should Know About Masonry - The Manufacturing Process

Brick manufacturing today follows fundamental procedures pioneered centuries ago. However, better knowledge of raw materials and their properties, better control of firing and improved kiln designs have resulted in a superior product. The production of bricks centers on the type of clay that is used. Clays occur in three forms (Surface Clays, Fire Clays & Shale). Although they share similar chemical compositions, they will differ in their physical characteristics. All properties of brick are affected by the composition of the raw materials and the manufacturing processes. Essentially brick are produced by: (1) mixing ground clay with water, (2) forming them into desired shapes, (3) then drying and firing them. Establishing a homogeneous blend is necessary before subjecting the mixture to one of three forming processes (Stiff-Mud, Soft-Mud or Dry-Press). Next, the process continues with drying, firing and cooling. Kiln firing temperatures during manufacturing graduate from 400°F to 2400°F.

Hardness of Bricks

There are many different types of brick (Building, Facing, Hollow, Paving, Ceramic Glazed and Thin Brick), and different scales of hardness. The strength of a unit is used to determine its durability and cutability. Both compressive strength and absorption are affected by properties of the clay, method of manufacturing and degree of firing. Most bricks have a strengths ranging from 3,000 PSI to over 20,000 PSI; averaging around 10,000 PSI.

Brick may also include different size, type and volume of aggregates to further strengthen the mix.

What You Should Know About Stone

Natural and Pre-cast Stones vary significantly in their geographic origin, mineralogical composition, and physical and mechanical properties. There are numerous types of stone to select; with each one exhibiting specific qualities of compressive strength and abrasive resistance. Additionally, these qualities would dictate appropriate diamond blade selection to effectively handle cutting requirements.

Your Choice of Stone Requires a Specific Type of Diamond Blade

General Characteristics of Stone

The complex nature and variables of Natural and Pre-Cast stone make it difficult to generalize their overall physical and mechanical properties. Unless the operator has had experience in cutting a particular stone, there are methods that can help predict the stone's sawability, and so determine the "best" diamond blade. The American Society of Testing and Materials (ASTM) recognize several physical property measurements that can identify a stone's hardness:

• Uniaxial Compressive Strength (UCS) - Measuring basic rock strength parameters. Commonly measured in Pounds Per Square Inch (PSI)
• Cerchar Abrasivity Index (CAI) - Measuring a rocks abrasiveness for determining cutting wear rates. The index is defined by a graduated numerical scale: lower numbers indicating less abrasive qualities, and therefore greater hardness.
• Mohs Hardness Scale - A scale of hardness applied to minerals that ranges from 1 to 10 indicating one from the other's scratch potential. Higher numbers indicate harder materials.
• Shore Scleroscope Hardness Test - A dynamic indentation hardness test using a number to indicate the height of a rebounding hammer off the surface of the material. Higher numbers indicate harder materials.

It is recommended to review all data relating to a stone's hardness and abrasive qualities to effectively choose the proper diamond blade. No singular Property Measurement Test can define the characteristics a stone would exhibit during the cutting process. As a general reminder for stone diamond blades: tests and industry experience has documented that stone exhibiting a greater degree of hardness and abrasive resistance require softer bond matrixes.

Conclusion

The preceding information has illustrated the unique physical properties of common building materials that often require sawing or drilling. Over the years, diamond blades and tools have consistently demonstrated their reliability, economy, performance and safety. The singular most important factor an operator of diamond blades and tools can recognize is matching the proper blade with the material to be cut.

Aggregate Map

Application Chart (Recommend Blade Selection)

Trouble Shooting

Segment Loss
Cause		Remedy
The material slips during cutting which twists or jams the segment loose.		Hold the material securely while cutting.
Blade is too hard for the material it is cutting, causing excessive dullness which causes the segment to pound off, or fatigue.		Use a softer blade specification.
Worn blade flanges fail to provide proper support and cause the blade to deflect.		Replace both blade flanges.
Out-of-round blade rotation resulting in pounding, caused by worn arbor or bad bearings in the shaft.		Replace worn arbor and/or bearings.
Overheating. Usually easily detected by blue color on steek center, generally confined to the area where the segment was lost.		Check the water system for blocked water passages. Test pump to see if it is functioning. For dry cutting, it may be necessary to make shallower cuts and allow the blade to run freely every few minutes in order to let the air cool it.
Loss of Tension
Cause		Remedy
Blade is being used on a misaligned saw.		Check for proper saw alignment.
Blade is excessively hard for the material being cut, creating stress on the steel center.		Make certain blade is correct for material being cut.
Material slippage causing blade to twist and become kinked or bent.		Maintain a tight grip on the material while sawing.
Utilizing blade flanges that are under size or not the same diameter, creating uneven pressure on the center.		Make certain blade flanges are proper size and identical diameter, minimum 3-7/8'', 4-1/2'' on concrete saws, 6'' minimum on diamond blades that are 30'' diameter and larger.
Blade being used at improper RPM.		Make certain blade shaft is turning at the proper RPM by using a tachometer. This is especially important with concrete saws.
Blade improperly mounted on arbor shoulder becomes bent when flanges are tightened.		Hold blade securely on arbor shoulder until outside flange and nut are firmly tightened.
Eccentricity
Cause		Remedy
The bond is too hard for the material being cut. The hard bond retains the diamonds, and they begin to round off, causing the blade to become dull. Instead of cutting, the blade begins to ''pound'', causing the blade to wear out-of-round.		Change to a softer bond, which will wear away more readily allowing the dull diamonds to be released and sharp, new cutting edges to become exposed.
The saw blade shaft may have a groove scored in it, caused by a blade spinning between the flanges. A new blade, installed on the arbor shaft, will seat into the groove, and immediately run eccentrically when the saw starts.		Replace worn shaft.
If the blade shaft bearings are worn, the shaft and mandrel will run eccentrically, causing the blade to wear out-of-round, This happens most often with concrete saws when proper lubrication of the bearings is neglected.		Install new blade shaft bearings. In some cases it might also be necessary to replace the blade shaft if it is worn or out of alignment.
Overheated Blade
Cause		Remedy
Adequate coolant was not provided.		Check the water supply for adequate volume and for obstructions in the water system. Use dry blades ONLY for shallow cutting (1-2'' deep) or step cutting. Allow blade to run freely every 10 to 15 seconds in order to increase cooling airflow.
Arbor Hole Out of Round
Cause		Remedy
Saw arbor badly worn due to improperly seated blades.		Be certain the blade is properly seated on arbor before tightening flange.
Blade flanges not properly tightened permitting blade to rotate on shaft.		Always wrench tighten the arbor nut. Never hand tighten. Always use hex nuts. Never use wing nuts.
Blade flanges or arbor shaft worn and not providing proper blade support.		Check blade flanges or arbor shaft for wear. Both flanges should be no less than that recommended by the manufacturer. Replace worn parts.
Blade Won't Cut
Cause		Remedy
Blade is too hard for materials being cut (Examples: block or general purpose blade being used for extended period on hard brick. Asphalt being used to cut hard concrete).		Consult dealer or manufacturer for proper blade to cut materials on job.
Insufficient power to permit blade to cut properly. (Loose V-belts, low voltage, motor lacks horsepower.)		Check belts, voltage, horsepower.
Blade has become dull because of continuous use on fairly hard or vitrified material.		Dress with abrasive material until diamonds become exposed again. (This may be necessary occasionally, but if dullness occurs too often, then the blade is probably too hard for the material.)
Blade segments appear to still have plenty of life, but blade won't cut.		Some harder-bonded blades designed for abrasive materials require a non-diamond bearing section at the base of the diamond segment for better adherence to the steel core. A blade used to this stage has worn out in the normal manner and should be replaced.
Excessive Ware
Cause		Remedy
Using the wrong blade on highly abrasive material. (Example: glazed tile blade on concrete block.)		Consult the dealer or manufacturer for the proper blade specification for abrasive material.
Lack of sufficient coolant to the blade. Often detected by excessive wear in the center of the segment. (Note: in both above cases, diamonds will usually be highly exposed.)		Clean up water system. Make certain water pump is functioning properly.
Wearing out-of-round accelerates wear. Usually can be caused by bad bearings, worn shaft or using a blade too hard for the material being cut.		Check bearings and arbor. If worn, replace with new parts before installing another blade.
Insufficient power caused by loose V-belts, inadequate voltage, or improper RPMs.		Tighten belts (taut). Replace worn belts. Check voltage. User proper extention cord.
Cracked Core
Cause		Remedy
Blade is too hard for material being cut.		Use correct blade with softer bond.
Excessive cutting pressure, or jamming or twisting the blade in the cut can cause the blade to bend or flex. When subjected to extreme stress and metal fatigue, the blade's steel core will eventually crack.		The saw operator should use steady, even infeed pressure, and be careful not to twist or jam the blade in the cut.
Overheating through inadequate water supply or improper use of dry-cutting blades.		Use adequate water to cool wet-cutting diamond blades (for example, 2-5 gallons per minute for concrete saws). Allow adequate airflow around dry-cutting diamond blades to prevent overheating.
NEVER USE A BLADE WITH A CRACKED CORE!
Undercutting
Cause		Remedy
Undercutting is a condition in which the steel center wears faster than the diamond segment, especially in the areas where the segment and core are joined. The condition is caused by highly abrasive material grinding against the blade during the sawing operation. Usually materials containing sand are responsible for this condition. (SEGMENT LOSS)		The flow of swarf (abrasive cuttings) must be distributed over a wider area, away from the critical segment area with undercut retardant segments or other types of undercut protectors specially positioned around the steel center to change the pattern of constant abrasion. Although successful in most cases, undercut protectors do not provide 100% protection.
Uneven Segment Ware
Cause		Remedy
Segments are worn on one side, reducing side clearance. It's usually caused by misalignment of the saw or a lack of sufficient water on both sides of the blade.		Check saw alignment. Clean water system, making certain that water is properly applied to the leading edge of the blade flanges. Check to see if pump is supplying sufficient, even water. Replace bearings or worn arbor as required
Blade is worn out-of-round due to bad bearings, worn arbor or excessive dulling condition.