Selecting Diamond Blades - Diamond Blade Guide - Diamond Blade Usage Recommendations - Sawing Equipment Guide - Optimizing Diamond Blades - How to Compare & Evaluate Blades - Diamond Tools Usage
EVALUATING & COMPARING DIAMOND BLADES TO OPTIMIZE PERFORMANCE
testing procedures and methodologies must be set up and used to obtain accurate
as well as repeatable testing results.
are some of the most important variable factors that affect diamond blade
performance and which should be considered in any test evaluation
diamond blade manufacturers do a certain amount of testing of their own
products. In order to improve existing products, develop new products, compare
against competition and etc. Each blade manufacturer typically uses their own
methodology and hence different manufacturers may produce various results.
this article we will attempt to provide some standardization in constructing
testing procedures. In general, the procedures set up and results obtained
within the manufacturers facilities will tend toward ideal conditions and
results. These results cannot necessarily be duplicated in the customers
facility. Their operating conditions undoubtedly will vary considerably from
those within the manufacturers plant. However, it must be realized that the
final test of a product is under the customers conditions and within their
facilities. This is known as “field performance”.
Generally most diamond blade manufacturers are in best position to engineer diamond blade tests. Equipped with proper equipment which is in reasonably good condition, operators who are familiar with the correct use of diamond blades, the adequate use and proper application of coolant, controlled speeds and feeds, adequate mounting of material to be cut, as well as other recommended conditions for the use of diamond cut off wheels. Under these controlled conditions the results obtained within the manufacturers facilities naturally tend toward the ideal.
is the experience of the diamond blade manufacturer that it is practically
impossible to obtain two identical cutting wheels no matter how carefully the
duplicate is made. Under strictly controlled laboratory test conditions,
supposedly identical cutting wheels can give cutting efficiencies which vary by
ten percent. Not only between the blades themselves, but between various
consecutive tests with the same diamond blade. Nevertheless, controlled test
conditions can point out consistent differences in a product and invaluable to
both manufacturer and end user. For the user they point up what results in the
way of greater production and lower costs he could expect if their operating
conditions were improved. For the manufacturer, this presents an opportunity to
make new developments to improve their products, to produce a more consistent
product and to compare their products with their competition with similar
specifications or intended uses.
is no universally perfect test procedures. However, any test procedure must be
able to duplicate results and to simulate the field application and to make it
possible to correlate these results with what may be expected in actual
applications. The testing procedure does not have to be elaborate, but should be
capable of providing complete information in order to properly evaluate test
results in light of customer requirements.
is the blade life?
the rate of cut?
the quality of finish? the types of materials cut. Why did the blade
perform as it did? Answers to such questions are needed in order provide a point
of departure for any future changes.
A test program must consider the amount of time and money available as well as the exactness of results required to meet customer objectives. Customers requirements must always be kept in mind when conducting tests.
and estimates can be made, however the results may not fit the field
conditions. One client may wish a fast cutting blade without too much
regard to wheel life, surface finish or chipping of material. Another
customer may be more interested in slower cutting blade with a longer
blade life and fair finish.
predicting diamond wheel performance it is important to take into
account the rate of wear of the diamond blade in relation to amount of
material cut, cutting time required and the power consumption. These
factors are essential so that all of the cost factors, including not
only blade cost, but labor and overhead costs as well, can be compared
for different types of diamond cut off wheels.
important factors to consider in conducting comparative diamond blade
setting up test process for use “in plant” which can also be used
“in field” for the determination of diamond cut wheel wear or wheel
life and cutting rate of the listed variables.
2 and 3 will not be considered since, normally this information is known
only to the manufacturer. Also, in general since “in field” tests
are concerned mainly with testing one blade against another under
similar conditions for a specific application, all the variables except
2 and 3 should be analyzed and considered.
material being cut and its variations plays a major role in determining
life of a diamond blade. Unfortunately there is no universal diamond cut
off blade which will cut thousands of different types of non metallic,
hard and brittle materials efficiently and economically. It is therefore
necessary to have different specifications for different materials or
groups of materials.
conducting the tests it is most essential to use the same materials and
to have the materials as consistent as possible in structure and
hardness. If a variety of materials are being cut, a logical weighting
system must be used in taking into account the structure, hardness,
grain size, etc. and to resolve the variations to a common denominator.
The feed rate or the speed at which the diamond blade moves through the material being cut, has a very pronounced affect on the cutting results. It is closely related the depth of cut, the structure and the hardness of the material being cut and the blade specification. Never force the diamond blade beyond its cutting ability. This will only result in a glazed diamond blade, poor cutting and shortened blade life. For any accurate comparison of results, the feed rate must be the same for all tests which are designated for the same purpose.
following example shows graphically the affect of varying rates of feed:
diameter – 14” diameter
speed – 7,000 SFPM
of cut – ¼”
of material cut – hard granite
Feed Rate Blade
81,253 sq in
55,624 sq in
this cutting application can be seen the affect of varying the cutting
feed rate on diamond blade cutting efficiency. When the blade was not
crowded by kept within the recommended operating conditions, about 45%
greater blade life was obtained. In other words, we have reduced our
blade cutting cost about 33%.
SPEED OF THE BLADE
speed of the blade – SFPM – is directly proportional to the RPM and
has a very pronounce effect on the cutting results. It must be closely
check and kept the same for each comparative test.
The cutting ability and life of the diamond cut off blade is closely related to its SFPM and material being cut. For a specific material, too high a peripheral sped may result in a glazed, dull blade with shortened blade life
correct blade speed will result in a blade operating at maximum
efficiency with lower cutting cost at a maximum cutting rate. For
general recommendations of diamond blade speed ranges for cutting few of
the non-metallic, hard and brittle materials, see recommended chart.
following example shows graphically the affect of varying the peripheral
diameter – 14” diameter
fed rate – 6 ft/mn
of cut – ¼”
of material cut – hard granite
Speed Blade Life
74,320 sq in
53,937 sq in
in this cutting application can be seen the affect of varying the peripheral speed of the diamond blade on cutting efficiency. When the speed was kept within the recommended operation conditions, about 38% greater blade life was obtained. In other words, we have reduced our blade cutting costs about 28%.
OF THE MACHINE
is common knowledge that no two machines will give identical results.
Therefore, for comparative results test should be made on one particular
machine. It is important that the machine be kept in good working
condition at all times during testing process.
machine in poor condition will result in worthless test data. Poor
bearings, poor shaft conditions, loose rolling table or blade carriage,
loose belts, dirty flanges et centers, will cause poor finish, short
blade life and other undesirable results. To reduce the affect of
unnecessary wear and poor cutting results, the machine should be checked
and serviced daily and completely overhauled every two months or more if
almost all diamond blade cutting applications some for of coolant must
be used. Cases when coolant cannot be used regardless of reason are
special and will not be considered in this article. Main purpose of
coolant is to keep the diamond blade cool so it will not wrap and cool
the localized points of heating resulting from each diamond particle
machining or grinding the material being cut. A coolant is also used to
clean away the swarf and to lubricant both the diamond particles and
material work piece. Improper use or application of coolant will result
in greatly shortened blade life, poor cut surfaces and damaged pieces.
The mere presence of coolant around the blade does not necessarily indicate that the coolant is being properly directed. For these reasons it is most essential to have an adequate supply of coolant under sufficient pressure to overcome any envelope of air surrounding the diamond blade caused by its rotation. Great care must also be taken to put the coolant on the blade and in the kerf in a proper manner so as to assure that the cutting surfaces are kept wet at all times.
are many types of coolant application systems – some quite elaborate
yet ineffective; others highly praised as ideal systems are found to be
grossly inadequate under actual cutting conditions. One of the most
simple systems the one used in this presentation is one that simulates a
turning fork and consists to two perforated pipes extending along the
sides of the blade into the center and connected to common pipe at the
outer end and fastened to the blade guard. The flow of coolant is
directed downward at approximately at 30 degree angle to the rotating
blade. With the flow applied in this manner, jets of coolant will
penetrate the air envelopes surrounding the rotating blade and cling to
the surface of the diamond blade instead of bouncing off.
coolant will then spiral to the periphery of the blade in a thin wheel,
wetting the cutting surface and reaching the bottom of the kerf.
DEPTH OF CUT
in case of fed rate, depth of cut has a very pronounced affect on blade
life and cutting performance. In cutting the softer materials such as
stone and the more open structured, loosely bonded materials, the full
depot of cut can be made in one pass. In the harder, denser materials
such as most granites, fine grained alundum, it is necessary to use step
cut procedure. If too great depth of cut is taken, the diamond blade
will become glazed and dull with poor performance. It is therefore
necessary to establish and maintain a definite dept of cut depending on
the application and the material being cut.
As everyone is aware, the operator of the machinery can either “make” or “break” the performance of diamond cut
wheel. This is true whether the operation is manual or automatic. Some
operators can make almost any diamond blade perform to maximum
efficiency, while other do not have this feel, ability, or experience.
It is therefore necessary in any comparative test to use the results
from one/same operator.
best performance of diamond blade a constant peripheral speed should be
maintained through the cutting period. Since one of the factors
affecting the life of the blade is the wheel speed – SFPM – any
fluctuations during the cutting period and tests must be eliminated or
reduced to a minimum.
power must be supplied to the driving shaft to assure a constant RPM.
that some of the fundamental requirements for a sound testing program
have been briefly analyzed, we can set up some realistic testing
procedures. Taking the operating conditions and requirements discussed
into account, a simple yet informative procedure can be established for
use either in the laboratory or in the field.
much will it cost to cut a specific material of a certain size? To
answer this question the testing procedure set up must give:
FOR TESTING DIAMOND CUT OFF BLADES
material / application will require different testing procedures and
methodology. Testing conditions, equipment and desired results will vary
with each group.
setting up the group procedure, one piece of equipment common to al will
is not always practical to completely wear out the blade to obtain the
desired data. In those instances where we wish to obtain results without
testing a blade to destruction, we use the technique of measuring the
wear on the blades at specific intervals and projecting this information
to give a theoretical blade life. It is assumed that the rate of wear
will be reasonable uniform through the usable diamond depth. To verify
the results, total life tests must frequently be made.
measure the wear on blade all that is needed is to obtain a difference
between the initial diameter and the diameter after the blade is used.
For this we can use a vernier caliper, tubular micrometer or similar
What you should know before you buy your next diamond blade?
UKAM Industrial Superhard Tools Division of LEL Diamond Tools International, Inc.
28231 Avenue Crocker, Unit 80 Valencia, CA 91355 Phone: (661) 257-2288 Fax: (661) 257-3833
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