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  • DUS TECHNOLOGY LLC.

  • DUS Technology – USA www.dustechno.com 2

    INDEX

    Summary………...………………………………….…………………………..…… 3 History …….………........................................................................................... 3 Types of Diamond Tools ….………………………………………………………. 3 How Diamonds are Applied on Tools………………….……………….….……….. 6

    Synthetic Diamonds ……………………………………………………………… 6

    Matrix………………………………………………………….…………………...… 7

    Diamond Powder Characteristics………………………………….……..……… 8

    Metal Bond …………..………………………………………………………..…… 9

    Segment Technology ……………………………………………………………… 10

    Interface Segment to Base ……………………………………………………….. 11

    Diamond Tools Specifications …………………………………………………… 12

    Concrete Aggregate on USA ……………………………………………………… 18

    Diamond Blade Troubleshooting ………………………………………………… 21

    Cutting Guidelines …………………………………………………………………. 26

    Production Costs Highlights ………………………………………………………. 27

    Why DUS Tools …………………………………………………………………..… 29

    Mr. Renato Cunha Technical Director

    Metallurgical Engineer Master of Science in Materials PhD by Trondheim University

  • DUS Technology – USA www.dustechno.com 3

    DIAMOND TOOLS TECHNOLOGY

    1- SUMMARY

    This is a simple and summarized diamond tools technology report for a quick reference.

    2- HISTORY

    Diamond is the hardest mineral available and diamond tools technology was developed to

    attend continuous growth of hard and abrasive products on construction and industry

    applications.

    Initially, diamond tools were manufactured with natural diamond grits, and consequently were

    very expensive.

    Most people don’t know this, but without diamond tools it would not be possible to develop

    some special refractory ceramics and extremely hard metals would certainly not have reached

    its actual development level.

    How to cut, drill or grind materials on industrial scale, fast, efficiently and with competitive

    cost?

    How to drill deeper and deeper holes for mining and oil extraction safely, fast and

    economically?

    Can you imagine how could titanium made orthopedic prosthesis be efficiently grinded?

    Wherever you can imagine, diamond tools were used in certain moments.

    3- TYPES OF DIAMOND TOOLS

    We can find diamond tools in several different ways, like:

    Powder: used for polishing of gems, glass, optical, etc

  • DUS Technology – USA www.dustechno.com 4

    Paste: used for polishing applications

    Saw blade: for cutting all kinds of hard and abrasive materials

    Hole saw: for small hole drillings

    Mining: developed in several parts to collect ground samples for research and

    identification of minerals.

    Oil and Gas tools: for prospection and extraction. These are like mining tools but with

    special characteristics.

    Concrete drill (core bit): to open holes for pipe lines and other things

  • DUS Technology – USA www.dustechno.com 5

    Diamond wire: to cut all kinds of big structures. Initially used for stones at quarries,

    nowadays are used for concrete and steel cutting as well.

    Gang saw frames: to cut natural stone blocks

    A variety of special designed tools for medical and dental purposes

    Grinding wheels: small and large diameters, for manual and complex automatic

    machine applications, to grind stones, concrete, refractory or any hard material.

    Special designed tools for polishing hard metals, glass, optics, ceramics and etc.

    Polishing pads: to polish any materials like stone, refractories, concrete and etc.

  • DUS Technology – USA www.dustechno.com 6

    Poly crystalline diamond (PCD): assembled on several metal tools to cut, polish or drill.

    4- HOW ARE DIAMOND GRITS APPLIED ON TOOLS?

    In general, diamond tools consist of two parts: base and diamond.

    Base: is the part to be connected to the machine where the diamond tools will be

    operated, for example the steel circular blank on saw blades.

    Some bases are metal made but some are plastic made, like fine pads for stone

    polishing.

    Bases are designed accordingly to the machine where the diamond tools will be used.

    Diamond: is the part responsible for the cutting.

    Diamond grits must be fixed on the base. So, it must be glued or joined on a special

    shape designed to perfectly attend its application.

    The most popular way to join and affix diamonds is by sintering metal bond, but some

    other methods are also used, like ceramic bond and electroplating.

    Note: it is right to say that diamonds are cutting. Observe that in fact diamonds on all

    kind of applications are really cutting the material. Diamonds are what get the job

    done!

    5- SYNTHETIC DIAMONDS

    It is not possible to move forward without discussing about synthetic diamonds.

    Not long ago, around late 80’s, synthetic diamonds production technology was still in very

    small scale and in the hands of a few players, making the cost extremely high.

    Only in the beginning of the 90’s, synthetic diamond grits became more popular and the price

    was dramatically reduced, allowing the growth of diamond tools. Nowadays a 4” diamond saw

    blade can be acquired on virtually any supermarket, simplifying workers and normal citizens

    cutting jobs.

  • DUS Technology – USA www.dustechno.com 7

    Synthetic diamond is carbon on crystal arrangement. With this arrangement, it becomes

    extremely hard and stable.

    On nature, the same carbon takes millions of years under special conditions (temperature and

    pressure) to go from its amorphous carbon form (graphite or coal) to a crystal form (diamond).

    Man has developed ways to force this physical-chemical transformation in a short period of

    time. A pure graphite block is put under an extremely high pressure (over 30.000 psi) and

    forces each carbon atom to re-organize on a crystal-like structure.

    Comparative SYNTHETIC x NATURAL diamond:

    Natural grits are very expensive

    Low reserves of natural grits comparing with synthetic grits

    Synthetic grits have symmetrical shape

    Natural grits are more stable on high temperature

    Impossible to get PCD on natural diamond (synthetic technology allowed PCD

    development)

    Natural grits have higher friability. In the other hand, a mix of synthetic diamonds with

    different mechanical characteristics can help adjust the performance of the blade and

    cut.

    Geopolitical issues where natural diamonds are available, known as conflict or “Blood”

    diamonds.

    6- MATRIX

    Usually, diamonds are involved on a matrix. This matrix is responsible to retain diamond grits

    on its position while doing its job, I mean, to cut. This is the biggest “secret” of our industry

    and another important item that sets DUS apart from the competition. The mixing “recipes” of

    ingredients are kept close guarded and small differences will affect tool’s performance

    dramatically.

    Matrix development is continuous. Engineers are frequently working on it to reach higher

    tool’s performance while lowering the cost and improving the ecological impact as well.

    There are a few different forms of keeping diamond grits on position:

    Metal bond: a variety of metal powders (Co, Fe, Ni, Cu, Sn, W, Zn, and so on) are mixed

    with diamond grits and then pressed together and sintered. On this method, metal

    bond must be projected according to what it will be cutting in order to keep the

    diamond grit and expose new (and sharp) diamonds at the right time. If diamonds

    came out prematurely, the tool won’t last long. In the other hand, if diamonds are held

    too long in the matrix, it will get dull and this tool will probably stop cutting and will

    need to be sharpened. By sharpening I mean to use the blade on a very abrasive

    material to expose new diamonds. It is all in the recipe when making the segments,

    and this balance is fundamental.

  • DUS Technology – USA www.dustechno.com 8

    Metal bond tools are more applicable for cutting, drilling and grinding.

    Resin bond: in this case, diamonds are glued with resin and afterword heated and

    cooled under control. Usually, these tools are used for polishing with fine and extra

    fine diamond grits.

    Electroplated: in fact, there is not an exact material to glue the diamonds to the base.

    A solution where diamond grits are in will be responsible to put diamonds on the base

    surface. Initially, these tools were more applicable for glass, optical, dental and

    medical tools, but the development of this process is growing up and new tools are

    appearing where years ago could not even be imagined, like a diamond wire, for

    instance.

    7- DIAMOND POWDER CHARACTERISTICS

    Let’s discuss a little more about synthetic diamonds. It can help sales people to better

    understand diamond tools uses and performance.

    As already explained, synthetic diamonds are obtained from a pure graphite block under a very

    high pressure. It will allow element carbon to be aggregated on tetrahedral crystal, which is

    extremely hard.

  • DUS Technology – USA www.dustechno.com 9

    Diamond grits are classified according to its purity and size.

    There are several codes and specifications according to each manufacturer, so it is very

    important to find a reliable supplier of diamonds.

    Purity: for simple tools, like the multi-purpose 4” blades, purity is not a requirement.

    On the other hand, when drilling for petroleum for instance, only higher purity

    diamonds must be used. But what makes one grit better than another? During the

    transformation of graphite to diamond not all carbon fully does it. The more carbon

    completing this process, the higher the quality of the grain will be. So, imagine what

    can happen on the diamond tools market…

    But you can ask me: why is purity so important? The higher the purity the more

    compact and resistant the grains will be, which translates to a longer life for the tool.

    But the metal powder is also important on this balance. If you project a hard metal

    bond and use a low-quality diamond it means that this tool will not cut, because it will

    not be sharpened.

    Size: seems to be obvious that small or fine grains are only used for polishing, but that

    is not true! Some fine grits are also used to protect the matrix against early erosion.

    For saw blades, a grit mesh of 40/50 is the most popular. For polishing pads, it must be

    a fine powder, like 10 microns.

    Coated: recent technologies developed coated diamonds to increase resistance and

    adherence between diamonds grains and metal bond. Titanium is often used.

    Diamond concentration: is the quantity of carats per volume of segments (cm3). This is

    an international normalization usually applied by the manufacturers.

    Defining the best concentration for certain tool is complex. That will depend on other

    factors like metal bond, diamond quality and size, and of course tool characteristics of

    speed and life trying to be achieved as wel as materials being cut.

    “Playing” with purity, sizes, concentration and coating of diamonds is a constant engineer’s

    challenge and one of DUS’s biggest advantages over the competition!

    8- METAL BOND

    Let’s dedicate some time on certain important considerations regarding metal bonds due to its

    importance to the diamond tool’s performance and the environment.

    Cobalt, pure or alloyed to other metals, is largely used. But it is important to register how

    dangerous this metal is for human health and the environment. Not only workers on

    production but also final users will be in contact with this carcinogen metal. But if cobalt is a

  • DUS Technology – USA www.dustechno.com 10

    good metal for diamond segments, with perfect mechanical and chemical characteristics, is it

    possible to substitute it while preserving good performance? The answer is yes.

    New metal bonds are being developed exactly to reduce cobalt use, which is also very

    expensive. But attention must be taken on this matter, because a lot of companies are not

    reaching the same performance.

    To understand a little more about metal bonds, it is important to know how they are applied:

    Powder: some companies use metal powder and diamonds, which are mixed, directly

    on graphite molds. This is an old and simple process. On this process, there is a high

    risk of diamond segregation, meaning that diamond grains will not be homogenously

    distributed and performance will not follow any rule.

    There is also the possibility of mixing metal powders and diamond grains and then cold

    press it, but segregation is also a problem, even if some additive is used.

    Granulated: granulation is the act or process of forming or crystallizing into grains.

    Granulating metal powder and diamonds with granulation agent and under low

    temperature guarantees better diamond distribution. The result are small balls (250

    microns) with the additional benefit of no dust, which is better for the worker’s health

    during the manufacturing process.

    A way to control the quality of the blades is to measure the final segment hardness, which

    usually is between 82 to 105 HRB (HBR is a scale to measure the hardness of material). A

    concrete drill segment has hardness between 92-95 HRB.

    9- SEGMENT TECHNOLOGY

    There are different technologies to produce segments, like:

    Sintering furnace: without pressure, usually with N2 or H2 atmosphere control. Ideal

    for 4” to 14” light service saw blades (in this case, segments or continuous ring are cold

    pressed directly on steel saw body)

  • DUS Technology – USA www.dustechno.com 11

    Hot sintering machine: with pressure, with or without vacuum, with or without gas.

    The newest machines have PLC (programmable logic controller is a digital computer

    used for automation of typically industrial electromechanical processes) control to

    allow that vacuum, pressure and temperature follow programmed curves for higher

    precision. These segments will be welded on the steel body as described below.

    Infiltration: this is a method were big diamond grains and PCDs (Polycrystalline

    Diamond) are positioned inside graphite molds as well as the steel body. This set is

    heated on furnaces under controlled atmosphere, or not. Mining drills tools are still

    manufactured by this method.

    Certainly, sintering is the most important phase of the diamond tools production.

    Sintering is the process where metals are almost melted around the diamond grains.

    The correct temperature will guarantee that metal powders are soft enough to involve

    diamonds, forming a strong matrix.

    The right pressure will eliminate spaces and holes to obtain a stronger matrix.

    10- INTERFACE SEGMENT TO BASE

    To link diamond segments to the base there are three ways:

    Cold press directly on the base: this is cheap but not very strong. It is more applicable

    on small diameters blades. Certain companies are producing up to 16” blades with this

    process for concrete cutting. Personally, I consider this a dangerous option.

  • DUS Technology – USA www.dustechno.com 12

    Brazed: after sintering, segments are cleaned (especially on the interface) and brazed

    to the base with silver or other alloys. There are two ways of brazing: by fire or by high

    frequency. High frequency is better due to a concentrated temperature on a reduced

    area for only a few seconds, causing minimum effects on the segments and body.

    Laser: special designed equipment position the segments in place and a laser is used to

    melt both sides. In this case, segments must have a diamond free backing. This is a

    very expensive machine. The specifications required for the segments and body shall

    increase the cost considerably.

    It is important to keep in mind that this process does not allow tools re-tipping, unless

    the body is cut. Diamond gang saws are not laser welded because they are re-tipped

    several times in their lifetime.

    Also, there is a limit on a tool’s size. You will not find large diameter blades laser

    welded.

    Silent blades are not available for laser weld.

    11- DIAMOND TOOLS USE AND SPECIFICATION

    Would be fantastic if we could have an international standardization for diamond tools, but

    unfortunately there’s none.

  • DUS Technology – USA www.dustechno.com 13

    All customers expect some specific characteristics on tools.

    Usually, customers are looking for tools with maximum speed and maximum life.

    To reach maximum performance, tools must be specially developed for each customer. But it

    will be very expensive, unless we are talking about large quantities.

    In general, there are a few models of each tool, with market average characteristics able to fit

    any customer needs.

    If we have too many models of each tool, it will be more difficult to specify which one will fit

    better. Afterwards, there are too many variables: workers, machines and cutting conditions

    change.

    So, the best solution is to work with a minimum number of models of each tool. For example:

    14” concrete saw blade for general purpose, high reinforced concrete and green concrete to

    be later fine-tuned for specific applications and individual customer requirements.

    To start on a new market, I suggest a general-purpose tool. This tool will allow for a fast

    development of any variation.

    Here are some operational suggestions to follow:

    Wet or dry cutting: wet is always better for cooling, clearing segments and preserve

    the segment welding

    Peripheral Speed: as diamonds are cutting, they need to have speed. In general, saw

    blades cut from 25 to 45m/s. Of course, the larger the diameter, the slower the RPMs

    should be to preserve the same peripheral speed.

    Diamond Blade Speed Guidelines Diameter Recommended

    RPM*

    Never Exceed

    RPM

    4" (102mm) 9.000 15.200

    41/2" (114mm) 8,000 13,500

    5" (127mm) 7,200 12,200

    5-1/2" (140mm) 6,500 11,090

    6" (152mm) 6,000 10,185

  • DUS Technology – USA www.dustechno.com 14

    7" (178mm) 5,100 8,730

    8" (203mm) 4,500 7,640

    9" (229mm) 4,000 6,700

    10" (254mm) 3,600 6,115

    12" (305mm) 3,000 5,095

    12" High Speed Blades 6,300

    14" (356mm) 2,500 4,365

    14" High Speed Blades 5,460

    16" (406mm) 2,200 3,800

    16" High Speed Blades 4,725

    18" (457mm) 2,000 3,300

    20" (508mm) 1,800 3,000

    22" (559mm) 1,600 2,780

    24" (610mm) 1,500 2,550

    26" (660mm) 1,300 2,350

    28" (711mm) 1,200 2,185

    30" (762mm) 1,200 2,040

    32" (813mm) 1,100 1,910

    36" (914mm) 1,000 1,700

    42" (1067mm) 800 1,455

    48" (1219mm) 700 1,275

    Core drills most follow a simple rule: up to 1 ½”, 1600 rpm; from 1 ½” to 6 ¼”, 1200 rpm; from

    6 ¼” to 12”, 500rpm; over 12”, 250rpm. Of course, the operator must pay attention to re-bars

    concentration, because it can suggest a reduction of speed.

  • DUS Technology – USA www.dustechno.com 15

    Diamond Core Bit Speed Guidelines Wet/Dry Bit RPM

    Diameter Min. Ideal Max.

    2" 1,200 1,600 2,000

    3" 800 1,050 1,300

    4" 600 800 1,000

    5" 475 640 800

    6" 400 560 665

    7" 340 450 600

    8" 300 400 500

    10" 240 320 400

    12" 200 265 30

    14" 170 225 285

    16" 150 200 250

    18" 130 175 220

    Saw blade displacement: you can go forward as fast as possible, according to the

    material’s hardness. Take care with re-bars, they can suddenly appear and cause

    accidents. For certain fragile materials, faster speeds can cause broken edges,

    requiring expensive finishing.

    Cutting depth: if you want to cut concrete or asphalt with the maximum depth allowed

    by a blade diameter, consider that forward speed must be reduced. I suggest not to

    cut so deep each time and get faster forward speed. Cutting deeper on the first time

    can damage the blade and loose segments.

    Cured Concrete and Asphalt Blades Diameter CuttingDepth*

    12" (305mm) 4" (102mm)

    14" (356mm) 5" (127mm)

    18" (457mm) 7" (178mm)

    920" (508mm) 8" (203mm)

    24" (610mm) 10" (254mm)

    26" (660mm) 10-5/8" (270mm)

    30" (762mm) 11-5/8" (295mm)

    36" (914mm) 14-3/4" (375mm)

  • DUS Technology – USA www.dustechno.com 16

    42" (1067mm) 17-3/4" (451mm)

    48" (1219mm) 20-3/4" (527mm)

    * Cutting depth may vary depending

    on saw design.

    Green Concrete Blades Diameter CuttingDepth

    *

    6" (152mm) 2" (51mm)

    7" (178mm) 2-1/2" (64mm)

    8" (203mm) 3" (76mm)

    10" (254mm) 3-3/4" (95mm)

    * Cutting depth may vary depending

    on saw design.

    Hand-Held High Speed Blades Diameter CuttingDepth*

    4" (102mm) 1" (25mm)

    5" (127mm) 1-1/2" (38mm)

    6" (152mm) 2" (51mm)

    7" (178mm) 2-1/2" (64mm)

    8" (203mm) 3" (76mm)

    10" (254mm) 3-3/4" (95mm)

    12" (305mm) 4" (102mm)

    14" (356mm) 5" (127mm)

    * Cutting depth may vary depending

    on saw design.

    Core drill displacement: for any diameter, start slow. After 1” deep you can go a little

    faster.

    Be careful when rebar is reached, it can suddenly break machine and segments.

    I suggest not press down and wait for the diamonds to do the cut.

  • DUS Technology – USA www.dustechno.com 17

    It is better to go down little by little, about one inch at a time. Press 1” down, refresh,

    down, refresh.... It will increase tool’s life by removing debris (cut material) from the

    hole and increase cooling.

    lost segments: even if you lose one segment you can still use your tool, but be careful,

    especially when cutting reinforced concrete.

    If the tool is almost new, try to find the lost segment. It will be easier to fix it later.

    Small diameter blades: these tools are commonly used by DIY. So, special attention

    regarding high speeds must be taken and speeds over 10.000rpm avoided. Double

    check if they are well assembled and secured in place.

    Machine power: machine power shall be proportional to the diameter used. For

    example, a 6” core drill shall operate with minimum 2600W motor. In another hand, a

    24” core drill will better perform on a hydraulic motor machine.

    10” to 18” saw blades shall not be operated under 5HP electric motor.

    Walking behind machines (non-electric): these are machines where the operator

    accelerates (pushes) it and speed is not constant. Machine (blade) shall be spinning on

    the right speed before the start of forward or down movements, otherwise saw blade

    may be damaged. The same recommendation must be followed when stopping the

    machine. First stop forward and down movements before stopping the rotation.

    These larger machines require more power. 8HP motors or higher are recommended.

    They also frequently run on uneven ground or floor. The non-axial movements can

    seriously damage the saw blade, even possibly breaking it. On roads where asphalt has

    small holes, side to side movements can occur and damage the saw blade as well.

  • DUS Technology – USA www.dustechno.com 18

    12- CONCRETE AGREGATES ON USA

    One of the key factors that determines the performance of diamond saw blades and drill bits is

    the type of aggregate in the concrete or asphalt being cut.

    Aggregate is defined as the composition or mix of stone, gravel and sand used in paving

    materials like concrete and asphalt. Aggregate may be crushed or uncrushed. Crushed

    aggregate may be limestone, granite, sandstone, trap rock, etc. Sand and gravel are typically

    found in natural deposits, like riverbeds, stream courses or Lake Basins.

    Aggregate is generally divided into “fine aggregate” (passes through a No 4 sieve, 0.187’

    square opening) and “coarse aggregate” (almost all of which is retained on a N0 4 sieve and

    may range in size up to 3" particles).

    While recognizing that aggregate size and type can change completely in a short distance on a

    given project (say highway). It is generally true that aggregates are similar in certain

    geographical areas. This is primarily due to local availability of one type of material and the

    prohibitive cost of importing anything else.

    This aggregate map is not intended, nor should it be used to precisely define all aggregate in a

    given area. Instead, it is published as a “general guide” to the predominant aggregate hardness

    (as it relates to “saw ability”) likely to be encountered in the area defined by the various colors.

    It should also be pointed out that any aggregate can be cut. However, the cost of sawing is

    usually directly related to aggregate hardness and size. This map is simply a reference tool to

    provide a general sense of aggregate similarity in various areas of the country. A brief

    description of the predominant aggregate in each state follows.

    Alabama Aggregates vary from favorable materials such as limestone, sandstone, and blast furnace slag to hard materials such as quartzite. The harder aggregate materials are found in the Central and Southwest sections of the state.

    Alaska The predominant aggregates are gravel and crushed rock and would be

  • DUS Technology – USA www.dustechno.com 19

    classified as medium-hard.

    Arizona A medium-hard gravel aggregate is encountered in most of the state and medium-soft decomposed granite in some areas in the northern part of the state. Sand’s content tends to be highly abrasive.

    Arkansas A medium-hard granite aggregate is encountered in the southern two-thirds of the state and hard driver gravel aggregate in the northern and northeastern part of the state.

    California Medium-hard gravel aggregates are encountered in the El Centro through San Diego area as well as in the northern part of the state. A medium to medium-soft aggregate is encountered in the San Clemente, Los Angeles, Paso Robles, Lancaster and Bakersfield area.

    Colorado The northern part of the state has medium to medium-soft aggregate comprised of decomposed granite. The Denver area and southeastern and eastern sections have medium-soft decomposed granite, limestone and gravel. The Colorado Springs area consists of medium-hard gravel.

    Connecticut Generally the aggregates consist of medium to medium-hard traprock and dolomite.

    Delaware The major portion of the state contains medium-soft traprock and limestone aggregates. The Wilmington area does produce a medium-hard gravel aggregate.

    Florida Generally the aggregates are composed of soft shell and argillaceous, siliceous and dolomite limestone. The northern area sometimes uses hard Georgia and Alabama aggregates

    Georgia Aggregates in the northern part of the state are medium-soft sandstone and limestone. The southern three-quarters of the state have medium-hard to hard granite, schist, gneiss, and quartzite aggregates.

    Hawaii Aggregate conditions throughout the islands are of the medium-hard, basaltic type.

    Idaho Generally medium-hard crushed stone and gravel aggregates.

    Illinois Aggregates in this state may be divided into three sections, the northern area medium to hard gravel, the central section medium gravel and limestone, the southern area soft limestone.

    Indiana The state has generally soft crushed limestone except in the southern and northwestern sections where medium-hard Ohio and Wabash river gravel occur.

    Iowa In the Des Moines and central Iowa area medium-hard pit and river gravel are typical. Aggregates found in the eastern, central and southwestern sections are soft limestone. The eastern border along the Mississippi River has hard river gravel. Medium-hard pit gravel with quartzite is found in the northwestern section.

    Kansas The aggregate conditions generally found are soft limestone. Medium-hard limestone, dolomite and hard gravel are found in the southeastern section, and medium-hard pit gravel in the north central area.

    Kentucky Approximately 90% of the state has aggregates of medium-soft limestone and

  • DUS Technology – USA www.dustechno.com 20

    sandstone. The northern section along the Ohio River has medium-hard quartzite river gravel.

    Louisiana Aggregate conditions in the state range from soft shell to hard gravel.

    Maine In general medium-hard dolomite gravel and some traprock is encountered in this state.

    Maryland About 60% of the state has medium-soft limestone aggregate. The balance of the state has medium-hard river gravel.

    Massachusetts The aggregate generally found is medium traprock except in northern section bordering New Hampshire where the aggregate is medium-hard.

    Michigan Generally medium-hard glacial gravel is found. The Pontiac, Flint, Mount Clemens area contains fair amounts of hard gravel or flint.

    Minnesota Aggregate in the central and northern part of the state consists of medium-hard glacial gravel. Medium-soft mined limestone prevails in southern.

    Mississippi Hard and medium-hard aggregates are found in the southwest section of the state and consist of the gravel and quartzite.

    Missouri Soft limestone aggregate predominates in this state with a hard gravel aggregate in the St. Louis area (Meramec River gravel) and a similar hard flint aggregate in the Joplin area.

    Montana The eastern section is a hard aggregate area, the Great Falls area contains medium-hard gravel and crushed stone aggregate and the Glasgow and Miles City areas have hard quartz and gravel aggregate.

    Nebraska Eastern and Central areas contain a medium limestone and gravel mixture and the Western areas have straight medium-hard gravel aggregate.

    Nevada The predominant aggregates are medium to medium-hard gravel and crushed decomposed granite.

    New Hampshire

    Generally medium-hard to hard granite gravel aggregates are encountered.

    New Jersey The predominant aggregates are a medium trap rock and hard river gravel.

    New Mexico Northern areas contain medium-soft aggregate shipped in from Colorado. A medium limestone with some quartz aggregate is encountered in the southern part of the state (Gallup, Alamogordo, Deming and Lordsburg). The Tucumcari area has medium-hard gravel aggregate. A medium-hard to hard gravel is encountered in the Albuquerque area.

    New York There are three predominant aggregates in this state, a medium-soft limestone, medium trap rock and medium to medium-hard granitic gravel.

    North Carolina Medium-hard and hard aggregates exist throughout the state and consist of granites, schist, gneiss and quartzite. Medium limestone is scattering.

    North Dakota In general medium-hard glacial gravel is encountered consisting of limestone, granitic gneiss, basalt, quartzite and gravel. In the eastern half of the state the aggregate combinations are medium-soft.

    Ohio Generally medium-soft pit gravel is encountered throughout the state except in the areas along the Ohio River where a medium-hard river bed aggregate is

  • DUS Technology – USA www.dustechno.com 21

    used.

    Oklahoma Soft limestone is generally encountered except in the western section where a medium-hard granite aggregate is used.

    Oregon The western section contains a hard granite aggregate an on the east side of the mountains a medium crushed gravel is encountered.

    Pennsylvania Generally medium-soft limestone and medium trap rock aggregate are encountered except in steel mill areas where soft slag might be used. Pit gravel is commonly used in Philadelphia area.

    RhodeIsland A medium hard trap rock aggregate is generally used throughout the state.

    South Carolina Predominantly the aggregates consist of a medium-hard quartzite, granite and gneiss with some limited amounts of medium-soft crushed limestone and marble.

    South Dakota There are three types of aggregate encountered in this state. The eastern area consists of hard quartzite aggregate, the central portion has medium-hard gravel aggregate and soft limestone aggregates in the western section.

    Tennessee In general medium-hard aggregates are encountered throughout the state with some medium quartzite west of Nashville and hard gravel aggregate along the Mississippi River.

    Texas The predominant aggregate encountered consist of medium limestone and dolomite with a medium-hard quartzite around the San Antonio area and hard gravel along the Coast area.

    Utah Aggregates consist of medium gravel throughout the state.

    Vermont In general medium to medium-hard granitic gravel aggregate is encountered throughout the state. Large aggregate is often found.

    Virginia Medium-hard granite gates are normally encountered throughout the state with medium-hard to river gravel in the Norfolk and Washington D.C. areas.

    Washington Medium to medium-hard gravel and crushed stone aggregate encountered on the eastern side mountains and hard gravel aggregate on the western side and in the Seattle Tacoma areas.

    West Virginia The predominant aggregates consist of a medium limestone, except along the Kana where medium-hard to hard river aggregates are used.

    Wisconsin The southern section state contains medium-soft limestone gravel aggregates. Medium-soft glacial aggregate is found on north.

    Wyoming Medium to medium-soft stone and crushed rock are encountered throughout the state.

    13- DIAMOND BLADE TROUBLESHOOTING

    Blade worn out of round

    Cause Shaft bearings are worn (masonry and concrete).

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    Medicine: Install new blade shaft bearings or blade shaft, as required.

    Cause Engine is not properly tuned on concrete saws, causing surges in blade rotation.

    Medicine: Tune engine according to manufacturers' manual.

    Cause Blade arbor hole is damaged from previous mismounting.

    Medicine: Replace worn shaft or mounting arbor bushing. Bond is too hard for material, causing a “rounding” and wearing one half of the blade more than the other. Make certain that drive pin is functioning. Use proper blade specification

    Blade not cutting

    Cause Blade is too hard for material being cut.

    Medicine: Use a softer bonded blade. Select proper blade specification for material being cut.

    Cause Blade has become dull as a result of being used on too hard a material

    Medicine: Improper blade specification; blade is too hard for the material being cut. Use softer blade to reduce operating stresses.

    Cause "Dull" Blade

    Medicine: "Open" blade by dressing segment on abrasive block.

    Uneven segment wear

    Cause Insufficient water (usually on one side of blade).

    Medicine: Flush out water system and check flow and distribution to both sides of blade.

    Cause Equipment defects cause the segments to wear unevenly.

    Medicine: Replace bad bearings, worn arbor shaft or misalignment to spindle. Concrete saws, engine must run smoothly to prevent harmonic vibration.

    Cause Saw is misaligned.

    Medicine: Check saw head alignment for squareness both vertically and horizontally

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    Arbor hole out-of-round

    Cause Blade collar is not properly tightened, permitting blade rotation or vibration on the shaft.

    Medicine: Tighten the shaft nut with a wrench to make certain that the blade is adequately secured.

    Cause Blade collars are worn or dirty, not allowing proper blade clamping.

    Medicine: Clean blade collars, making sure they are not worn.

    Cause Blade is not properly mounted.

    Medicine: Make certain the blade is mounted on the proper shaft diameter before tightening shaft nut. Ensure the pin hole slides over drive pin. Make sure that drive pin is in pin hole.

    Cause Loose belton saw.

    Medicine: Tighten belts. Check to see if arbor on saw is running true.

    Under cutting the steel center

    Cause Abrasion of steel center due to highly abrasive fines generated during cutting.

    Medicine: Use as much water as possible to flush out fines generated during cutting, or use wear-retardant cores.

    Cause Cutting through material into sub-base.

    Medicine: Wear-retardant cores are not always the ultimate solution to eliminating undercutting. Your best defense is to always provide an adequate water flow to the steel center area immediately adjacent to the segment, especially important when making deep cuts.

    Segment cracks

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    Cause Blade is too hard for material being cut.

    Medicine: Use a blade with a softer bond.

    Cause Blade being "forced" through the cut causing chattering

    Medicine: Run Saw at normal speed. "Open" blade by re-sharpening in abrasive material.

    Blade wobbles

    Cause Blade runs at improper speed.

    Medicine: Check for bad bearings, bent shaft, or worn mounting arbor. Speed of the saw is either too fast or too slow for the size of the blade: RPM of the saw should be verified to the specific speeds established by the NASI Standards for minimum and Maximum blade speeds; make certain that blade shaft is running at recommended RPM to match tensioned speed of blade. Should the blade continue to wobble after verification of the saw RPM, then the blade should be returned to the manufacturer to be re-tensioned and flattened

    Cause Blade collar diameters are not identical.

    Medicine: Check blade collar discs to make sure they are clean, flat and of correct diameter

    Cause Blade is bent as a result of dropping or being twisted in the cut during operation.

    Medicine: Blade should be returned to the manufacturer to be re-tensioned and flattened.

    Cause Blade tension loss

    Medicine: (see loss of tension)

    Segment Loss

    Cause Overheating due to lack of water.

    http://www.mkdiamond.com/concrete/tec_troub.html#Anchor-33869

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    Medicine: Check water feed lines and make sure flow is adequate on both sides of blade.

    Cause Steel center is worn from undercutting.

    Medicine: Use sufficient water to flush out the cut.

    Cause Defective blade collars are causing blade misalignment.

    Medicine: Clean blade collars or replace if collars are under recommended diameter.

    Cause Blade is too hard for material being cut.

    Medicine: Use proper blade specification for material being cut.

    Cause Blade is cutting out of round, causing a pounding motion.

    Medicine: Replace worn bearings; realign blade shaft or replace worn blade mounting arbor.

    Cause Improper blade tension.

    Medicine: Ensure blade is running at correct RPM. Blade is tensioned for correct RPM. Engine must be tunedaccording to manufacturer.

    Cracks in steel center

    Cause Blade flutters in cut as a result of blade losing tension.

    Medicine: Tighten the blade shaft nut. Make sure blade is running at proper tensioned speed and that drive pin is functioning properly.

    Cause Blade specification is too hard for the material being cut.

    Medicine: Use a softer blade bond to eliminate stresses that create cracks.

    Cause Bad blade shaft bearing.

    Medicine: Replace blade shaft bearing.

    Cause Overheating due to lack of water.

    Medicine: Check water feed lines and make sure flow is adequate on both sides of blade.

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    Loss of tension

    Cause Steel center has been overheating as a result of blade spinning on arbor.

    Medicine: Check water flow, distribution and lines. Tighten the blade shaft nut. Make certain the drive pin is functioning (on concrete saws).

    Cause Steel center has been overheating from rubbing the side of material being cut.

    Medicine: Make certain blade RPM is correct so the blade operates at its tensioned speed. Tune engine according to manufacturers' manual.

    Cause Unequal pressure at blade clamping collars.

    Medicine: Blade clamping collars must be identical in diameter and the recommended size.

    Short blade life

    Cause Blade bond or matrix too soft.

    Medicine: Use a harder matrix blade.

    Cause Overheating due to lack of water.

    Medicine: Check water feed lines and make sure flow is adequate on both sides of blade.

    14- CUTTING GUIDELINES

    1. Machinery Check/Maintenance: Review engine maintenance procedures, condition of

    the guards and water tubes, determine whether V-belts and bearings need to be

    replaced. Check the condition of the blade shaft. The condition of your equipment is a

    major factor in the overall performance and life of both the saw and diamond blade.

    Proper maintenance will ensure years of useful service.

    2. Proper Power for the Cutting Application: The more horsepower (torque, not

    pressure on the blade), the more efficient the cut. Low horsepower saws may require

    a softer bond to compensate for the lower torque.

    3. Proper Speed For The Blade Diameter Used: Recommended operating speeds for

    most diamond blades is between 9.500-11.500 surface feet per minute. Lower speeds

    are used in harder more dense materials; higher speeds are used in softer more

    abrasive materials. When changing blade diameter size, check with the manufacturer

    or distributor, as to the proper operating speed for the size of blade you are using.

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    4. The Right Specification: Make sure that the blade that you are using is intended for

    the application/material you are cutting.

    5. Blade Mounting: When the blade is snuggled up evenly against the blade core the

    blade will run true and improve the maximum cutting efficiency. A bad seat could

    possibly produce lopsided wear or an egg shaped or burnt arbor.

    6. Blade Tension: Each blade is pre-tensioned to run true at the prescribed speed as set

    by the manufacturer. Blades that loose tension are prone to waffling or flutter,

    creating excessive side wear and eventually cracking of blade's blank (core). If the

    problem exists, return the blade to the manufacturer to be re-tensioned.

    7. Water Placement: Ensure that adequate water flow is properly distributed on each

    side of the blade during cutting.

    8. Water Volume: Water volume should be roughly 4.5-6 gallons per minute and not a

    high pressure flow to the blade. The proper water volume will depend on the flushing

    action required of the cut.

    9. Keep the Blade out of the Base: When cutting through asphalt or a concrete slab and

    into the sub-base, water loss will result. The abrasive nature of the sand in the base

    will cause premature wear on both the steel blank (core) and the diamond segments.

    10. Let the Blade do the Cutting: Excessive pressure on the blade while in the cut may

    cause the blade to glaze over the diamond crystals, creating stress cracks in the blank

    (core) causing the blade to become out of round. On lower horsepower saws, too

    much pressure may cause the blade to ride up out of the cut and cause the engine to

    stall. Listening to the engine is a key to smooth cutting.

    15- PRODUCTION COST HIGHLIGTHS

    Fighting for customers, manufacturers are continuously working to reduce price. But is

    that the right policy?

    Technology and quality has a price!

    Just to give you an idea, a simple 14” masonry blade has the following basic costs:

    3 carats (minimum), price per segment: US$ 1,00

    Metal bond: US$ 12,00

    Steel blank: US$ 6,00

    Add: labor, energy, grinding, granulation additives, silver brazing, cold press mold,

    graphite molds, paint, packing, transportation, etc... After sales, you can add: duties,

    insurance, commission, marketing…

    With this in mind, it becomes easier to understand the difference in costs for different

    blades and brands. If you apply the best raw materials, advanced technology in

    manufacturing methods and equipment, one brand might cost twice as much as

    another. Remember: there’s a price for good quality and you will get what you paid

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    for. For instance, a good blank or core will allow for several re-tipping and

    considerable savings on the long run. A fast blade will save on labor and a durable one

    will minimize the time spent on changing blades. A poorly made blade can break or

    loose segments, possibly injuring people. Materials used on the manufacturing of the

    segments will be released into the environment and will impact it.

    Protecting the environment is priceless, and so is supporting a green contract

    manufacturer who cares for it and uses no carcinogen materials.

    In this business, one of the most difficult things is to find the right product for each

    individual customer. What is the customer looking for? Is this customer only looking

    for one blade for a small job or for a reliable tool that offers fast cuts with reasonable

    price?

    Some contractors prefer to cut fast and complete the task in minimum time. Some

    prefer to take a little longer but guarantying a good cut for the best edge finishing

    possible. Some need a tool able to cut anything inside the concrete while others prefer

    a multi-purpose tool in order. Which way is better? There’s no right or definitive

    answer.

    Here are the points which make huge difference between companies.

    1- Companies need to have its own technology, otherwise will not be able to find

    the way to success or client satisfaction.

    2- Major of the company only work with their standard tools and will not change

    its production to accommodate a client.

    3- Some companies only play with low quality raw materials and will never be

    able to get certain characteristics on its tools

    4- To offer low price, some companies only produce large amounts of each

    model. Producing a smaller quantity of one item will enormously increase cost.

    5- Some companies definitively don’t care about the environment or even have

    an idea on how to use other ecological raw materials. Maybe they don’t have

    the technology and/or want to change its process to other raw materials

    despite of cost, because it could be more expensive (or maybe not)!

    Recently, some tools have come to the market with very low price. They also carry some

    special details: some production steps were eliminated to cut costs. For instance, granulation,

    cold pressing, brazing and side grinding might not be part of the process and these tools will

    have a diamond area directly pressed and sintered on the steel body. This information is

    usually kept from the customer. Do they work? Yes, they might get the job done but not in all

    applications.

    For industrial cutting, you will never see this kind of tool being used.

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    In summary, the market will have space for everyone because there will always be someone

    interested on different aspects of a tool.

    16- WHY DUS TOOLS

    DUS is a result of 24 years of experience with diamond tools on all kinds of products and

    manufactures worldwide.

    After listening to several customers during the years, DUS identified customer’s needs and

    decided which path to take.

    DUS is a small family operation company, where all production detail is individually treated for

    higher efficiency.

    All tools are tracked, from the beginning of production to the end and also after it leaves the

    factory, to guarantee its origin and quality.

    All manufacturing equipment uses the latest technology. No machine is older than a 2014

    model.

    While some companies cut corners to offer cheap products, DUS is committed and focused in

    developing new technologies to reduce price but keeping high levels of quality while caring for

    the client’s needs, its users and the environment. This is DUS’s philosophy.

    These are some of the reasons to use DUS diamond tools:

    a- The environment is our concern and DUS is engaged to improve it. Here are a few

    examples of our actions:

    No carcinogenic metal is used, like cobalt for instance;

    No waste of raw materials. Our process was developed with high efficiency in mind;

    No dangerous or hazardous materials are used;

    All metal-bonds use low and medium temperature sintering, resulting in high energy

    efficiency in our production;

    Rain water is used for machinery cooling and does not come in contact with the

    process or materials (stays clean);

    Water catchment system uses rain water for general use in the factory;

    Natural day light is fully used. No artificial lights are needed on the factory floor, and

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    Regarding cobalt use, it is important to know what we are talking about.

    Almost all companies use cobalt based metal-bond. As a reference, one diamond gang saw

    cutting everyday will throw away approximately 360 lbs. of cobalt per year into the

    environment.

    All DUS bonds are cobalt free.

    Our experience and technology allowed for the development of high performance tools

    despite of being cobalt free.

    b- Suit to customer needs: DUS is proud to be completely open to develop any kind of

    tools according to customer’s requirements, depending on minimum quantity;

    c- Fast cut and long life tools. Our technology allowed the development of fast cutting

    tools, with reasonable life and with competitive cost;

    d- DUS core drill bits have a special design to allow for a fast start and leveling.

    Frequently, concrete and asphalt surface are not really flat, causing some segments to

    touch in different times and causing high vibration. With our segment design, it is easy

    to compensate for this problem so any and all segments can easily adapt to the

    surface.

    e- Sandwiched segments. Multi-layer segments can offer internal and external layers with

    special specifications to increase performance according to customer’s requirements.

    f- Even Diamond distribution guarantees that performance is constant from the

    beginning. Tool will always perform in the same way.

    g- All blades are top and side grinded, to allow for high diamond exposure, offering a fast

    cut start.

    h- DUS segments have a very high retention of diamonds, keeping each diamond grain

    for a long time.

    i- Green Contract Electricity Company: stops work at electricity peak demand times.