is a Diamond Blade?
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- In construction work a variety of diamond tools may be used;
circular blades, drills, surface grinding wheels and cutting wires.
Each tool is different and has its own special application; the
method of working varies from one to another, but the basic principles
remain the same.
- For the sake of simplicity, we shall refer mainly to diamond-tipped
circular saw blades.
- A diamond 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 (please see diagram on Page 29).
- The metal centre of the segmented 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 whilst allowing it a certain 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 processed are used for fixing the segments or rims firmly
to the steel:
- 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.
- Laser Welding: laser microfusion 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.
- 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.
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
- Whilst the blade is rotating on the saw shaft, the operator
pushes the blade into the material. The surface diamonds thus
exposed mill a groove in the material, reducing it to fine powder.
Whilst the blade mills the material, the latter exerts wear on
- During cutting the exposed diamonds may crack or break (all
the more rapidly, the harder and denser the material). The material
simultaneously starts to abrade the metal matrix, which gradually
releases more diamonds. The more abrasive the material, the more
rapid the tendency to wear down the matrix.
- With a diamond tool properly matched to the material being cut,
the equilibrium between the work of the diamond and the resistance
of the bond to abrasion is at its optimum: the diamond is held
in place until it is destroyed and new crystals appear. The whole
quality of a diamond tool resides in this equilibrium.
- 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
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to select a diamond tool
- 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 (cost per
metre) is usually much more important than the initial price.
- 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.
- 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
- 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
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.
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