Selecting Diamond Drills - Diamond Drill Guide - Diamond Drill Usage Recommendations - Optimizing Drilling Operation - Drilling Equipment - Diamond Tools Usage
Optimizing your Diamond Drilling Operation
Frustration leads them attribute their problems to diamond drill drill being
used. What some customers refer to as serious problem for example, may be
resolved by something as simple as adjusting RPM’s or feed rate. The solution
can be as easy as changing mounting method, properly mounting drill in machine
chuck, or educating customer about need to dress diamond drill. Selecting
the right combination of these variables for a specific material / application
is both an art and science that often takes years to master. Information
presented in this article is not based on R & D, but primarily on many years
of process optimization experience.
Please, note most of the principals discussed in this article relate to sintered
(metal bond) diamond drills.
Please, note most of the principals discussed in this article relate to sintered (metal bond) diamond drills.
DRILL SELECTION – (Selecting the Right Diamond drill for your Application)
diamond drill application exhibits similar characteristics, whether its in
specification or performance. Below is a list of the most important
characteristics/parameters obtained from years of experience.
These parameters will play a major role in diamond drill performance. For the diamond drill manufacturer to recommend the right diamond drill for your application. It is critical that the customer provide as much application information as possible. The first step in this process is to consider the properties of the material to be drilled and to match diamond drill properties to this material. Table 2 shows a general matching of three basic diamond drill properties to three basic material properties.
Common non metallic materials drilled with diamond drills
vary from hard, dense products like high alumina to loosely bonded, highly
abrasive products like concrete block. No attempt is made to list specific
diamond mesh sizes, concentrations or bond hardness to drill these materials.
This information is to be used just as a guide in selecting diamond drill
Table 2 indicates that hard metal bonds are selected for highly abrasive material. Although physical prosperities are of primary importance in selecting drill properties, chemical properties can also play an important part. With refractory materials, for instance a high alumina content usually indicates that the material will be dense and hard requiring softer bond types and finder diamond mesh sizes.
Matching Basic Diamond Drill Properties to Material Properties
second step in the drill selection process is to consider the effects of
operating conditions on the diamond drill. Table 3 shows these
An operating condition which causes a diamond drill to have shorter life and a faster drilling rate is said to make the drill act softer.
A drill with longer life and slower drilling rate is harder acting drill (harder drilling action). Having tentatively selected a combination of diamond drill materials from the material properties guidelines in Table 2 a change in diamond drill materials is made if there is a specific operation condition which will affect diamond drill hardness as shown on Table 3.
of Operating Conditions on Drill Actions
third and final step in the diamond drill selection process is the consideration
of the customers stated drill preference, if any. Drilling rate (speed)
and drill life are the primary measurements most customers are concerned
with. Usually high drilling speeds reduce labor costs and high drill life
reduces diamond drill costs. There is an inverse relationship between
diamond drill life
and drilling speed. as diamond rill life increases, drilling rate deceases. The
most common customer preference is for a diamond drill which will
provide both longer life and a faster drilling speed. It is the job of
If diamond drill
is the most important customer consideration
cost of a diamond drill is primarily dependent on diamond content
(concentration). A popular misconception among end users is that diamond
content (concentration) and performance are directly proportional.
However this is not the cause. In practice, there is an optimum number
of diamond particles of a specific diamond mesh size in a specific bond
which will produce optimum performance for a specific application. On
many applications lower drilling costs are obtained user lower rather
than higher diamond concentrations which, in some cases will not drilled
all. For this purpose the customer should be concerned with performance,
application parameters are the most significant in making application
decisions? In general, the most important factor is the type of material
being drilled. Manufacturers recommended stock specifications have been
developed to drilled specific materials under average operating conditions
where no specific customer preference has been expressed.
example soft diamond bond, with coarse diamond size and high diamond
grade has been found to provide optimum performance on most alumina
OPTIMIZING DIAMOND DRILL PERFORMANCE
a any set of application conditions there is a combination of diamonds
and bond which will produce optimum diamond drill performance. Finding
that combinations depends on
Except on most common applications,
a successful initial diamond drill tests is rare. In many cases it may take
several attempts and adjustments on both part of customer and diamond drill
manufacturer to come to optimum solution.
Drill performance is adjusted by
changing drill materials, but it can also be adjusted by changing
operating conditions. Information presented in Table 2 and Table 3
implies certain application rules. Table 4 summarizes these rules
showing the effect of changing either drill materials or operating
conditions, holding all other variable constant.
are the few important rules which guide the diamond drill manufacturer
and customer in changing drill elements or operating conditions to
optimize drill performance
there are frequently exceptions. For example beyond optimum point O,
life decreases with increased concentration. This may occur
because the harder acting drills require dressing to maintain a
satisfactory drilling action, or increased infeed pressures may have to
be used to maintain satisfactory drilling rates.
Increased diamond size beyond optimum point O cause a drill to act harder because the coarser particles do not penetrate a very hard material. There is a complex relationship between the number of diamond particles in a drill and the contact area of a single diamond particle. For example a change from 20/30 mesh diamond to 30/40 mesh diamond at the same concentration level provides approximately three times as many diamond particles but reduces the individual particle contact area by approximately one third. It is common to expect harder bonds to produce longer drill life.
theory that supports the contradiction beyond optimum point O is that
harder bonds are more brittle and start to break away rather than wear
away, This causes shorter drill life
Other changes in diamond drill materials or operating conditions which make a drill act harder will produce similar effects. Contradictions beyond optimum hardness’s can be explained with similar theories. The accuracy of these theories is not important when considering the drill selection process.
is a critical factor which further complicates the drill selection
process. Some degree of variation is fairly common and is to be expected
involving most aspects of diamond drill usage, raw material composition,
operating conditions and etc.
sources of variation diamond drill applications:
factors can affect each of the variables listed above and methods used
to control and minimize these variations. Manufacturer of diamond drills
goes to great length to control the quality of the diamonds and powders
used and to control the processing conditions which affect the
performance of the finished product.
the same taken raw material manufacturers that supply material that is drilled
by diamond drills also have formable quality control standards to
minimize process and manufacturing variation. Unfortunately the drilled ability of these materials is seldom taken into consideration in initial
raw material design and process control when designing original product.
Refractory products for example are closely controlled for properties
such as thermal conductivity, spalling and refractoriness, but drilled ability (hardness and abrasiveness) is not specifically controlled.
Operating conditions are typically under poorer control than either
material properties or diamond drill properties. For instance, the
objectivity of the saw operator and the communicativeness of the
purchaser are major sources of variations that have important effect on drill
Typically the diamond drill manufacturing processes are in far better control than other factors of the application environment in which those diamond drills perform.
AFFECTS OF PRODUCT, PROCESS AND APPLICATION VARIABLES ON DIAMOND DRILL PERFORMANCE
This normal variation curve
represents a hypothetical population of diamond drill performance results on the
a specific application. The curve represented by range Rb depicts the
relative amount of variation caused by diamond product variables. Curve
represented by range RM accounts for the amount of variation cause by
variables in the material being drilled.
The range Ro represents the
variation in performance results due to variations in operation
conditions. The goal in this case is not to relieve the diamond drill manufacturer of the all responsibility of application variations, but it
does express the experience of diamond drill manufacturers.
One of the most difficult tasks an
application engineer faces is solving application problems that are
cause by variation. For example, in drilling one material typical drill life is average of 500
holes per drill is considered normal.
Figure 1 presents another frequency
distribution curve showing the average and range of performance on this
specific hypothetical application
DISTRIBUTION OF POSSIBLE DIAMOND DRILL PERFORMANCE RESULTS
NUMBER OF HOLES PER DIAMOND DRILL
represented by point A made 350 holes. The user of this drill is not
happy and may request a credit. However what the end user should realize
is that diamond drill life they have experienced is not out of the ordinary and
still falls within the normal distribution curve. When using this
particular diamond drill the user was affected by all variables
discussed above. Therefore, credit is not really warranted (despite what
the customer may feel).
problem occurs frequently and it is the diamond drill manufacturers
application engineers task to explain to the disappointed end user that
the 350 drilled holes performance level, although low is normal. In these
situations, note that diamond drill performance represented by point B is rarely
other hand if a diamond drill provided only 200 holes as shown
in point C, this would be outside the normal distribution curve.
There could be more than one explanation to attribute to this poor drill
performance. In statistics this performance would be attributed to
assignable cause. Finding and assigning cause and correcting the problem
behind this poor performance is a challenging task. Most customers
logically conclude that there is something wrong with this diamond drill. However, this is not always the case. In this situation it is
very important of the customer (end user) and drill manufacturer
(supplier) to face these circumstances with an open mind in order to
resolve the problem. Both
diamond drill manufacturer and user can dramatically benefit by working together
to resolve problem, instead of approaching it as advisories.
end users lack of cooperation with diamond drill manufacturer or supplier will
be costly to the end user. Important information will be lost unless the
end user communicates complete drill application information to
manufacturer can assist the end user by providing important
recommendations in changing operation conditions or usage parameters.
And in some cases provide different drill specification that will more
closely and better match customers application parameters.
important for the customer to understand that manufacturers do not rule
out diamond drill variability as cause of poor diamond drill performance. Its just very rare. Most diamond
maintain elaborate records documenting diamond drill manufacturing and
quality control process at every stage.
batch and drill produced is frequently assigned as serial number. Every
processes underwent in diamond drill manufacturing process can be
reexamined and traced to each individual diamond drill.
information is frequently inspected when looking into validity of
customer poor drill performance claims.
customers when experiencing poor diamond drill performance or variation
frequently assume the tool used (diamond drill) is at fault. Rarely do
these users consider material variations or changes in operating
conditions as a factor behind these problems.
DESIGNING DIAMOND DRILL TESTS
Rarely does the first
drill specification recommended by diamond drill manufacturer provide
optimized level of performance desired by customer. Even if by chance
the first diamond drill specification tested hits the target, subsequent drills
would not perform to most optimized level of performance. This is why
results of one diamond drill test is not particularly valid. It is recommended
that several drills of same specification by used to establish a average
and a range of performance results before adjusting a specification of
is therefore in customers best interest to sample as many drill specifications and their variations as possible to establish a precedent
(performance benchmark) from which they can measure all other diamond drills.
constructing field tests, the end user should attempt to control
operating conditions and material specifications as much as possible to
minimize diamond drill performance variation. For this reason laboratory
tests utilize statistical methods such as random or multiple drill deigns to minimize the affects all variables that may cause variation,
except for those being specifically evaluated.
are some of the methods used to control and minimize variation in
laboratory testing environment
The customer stands much to gain by
following proper diamond drill testing procedures.
DIAMOND DRILL PERFORMANCE RESULTS
customers ask the manufacturer to make certain predictions about diamond
such as “How many holes will this drill make?” are
frequently asked. Unfortunately, there is not real answer to this
question. Because it takes a considerable amount of time and patience to
explain all of possible variations behind diamond drill performance.
can performance results be more accurately predicted?
customer may achieve certain drill life or chipping level on specific
application. While another customer may experience longer or shorter
life on exact same material and application. Even though operating
condition and materials appear to be relative same. Any estimate from drill
manufacturer may be interpreted by customer as a commitment or
statement of performance guarantee. This is unrealistic and discourages
for objective testing, the results of which will benefit both customer
What you should know before you buy your next diamond drill?
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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