Selecting Diamond Blades - Diamond Blade Guide - Diamond Blade Usage Recommendations - Sawing Equipment Guide - Optimizing Diamond Blades - How to Compare & Evaluate Blades - Diamond Tools Usage
DIAMOND
BLADES - Selecting
the Right Diamond Blade for your application
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Precision Diamond Sawing Equipment
a.) Tile Saw d.) Surface Grinder e.) Dicing Saw g.) Precision Gang Saws h.) Industrial & Laboratory Diamond Band Saw e.) Other Equipment
An adequate diamond cutting saw for diamond blade use must provide:
Most Precision & Ultra Thin Diamond Blades are used on computer/cnc controlled precision cutting equipment. Equipment used by Manufacturing and Research & Development facilities is usually different. Precision Diamond Sawing equipment used by Manufacturing facilities world wide varies with industry used in, material dimensions, & materials machined. Semiconductor manufactures (chip makers) favoring dicing saws that are equipped with high speed air spindles capable of reaching up to 35,000 RPM. Precision Gang saws are used in high production scenarios of semiconductor packages (singulation), slicing of ultra hard & brittle materials, optics, as well as glass & quartz tubing, rods and many other materials. Smaller ultra hard, brittle material, and optics manufacturing operations use surface grinders for slicing, grooving, & slotting large variety of materials.
COMMON PRECISION DIAMOND SAWING OPERATIONS FOR INDUSTRY AND R & D
Diamond Slicing
Sawing. Machining operation in which a powered machine, equipped with a blade having milled or ground teeth, is used to part a material (cut-off) or give it a new shape (contour band sawing, band machining). Four basic types of sawing operations are: Circular or annular (I.D.) sawing This process utilizes a rotating circular, toothed blade to cut off the material much as a workshop table or radial saw cuts wood. The ring shaped blade operates under high tension and is held by a precision chick. The cuts made with this method are precise wit little material loss and a good surface finish. Dicing
Dicing (or diamond-wheel sawing) is used in the micro-electronics industry for fine, accurate, partial and cut-through of exotic, very hard and brittle materials into small squares, or die. Diamond wheel dicing is the most common technique in the industry because of the superior cut quality. It is possible to keep the cut width, depth, straightness, and edge quality within tight tolerances. Sectioning / Wafering
The first stage of sample preparation, metallography, and failure analysis process. A failed part or piece of material is cut off to be studies and observed in order to identify the origin and reason of part/material failure. The main objective is to cause as minimum material deformation to sample as possible and not alter material structure while cutting. Another important consideration is to minimize additional steps required for sample preparation process. Depending on the type of failure, it may be necessary to take several specimens from the area of failure and from adjacent areas. Gang Sawing
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principal advantage of gang saws is realized when cutting very hard materials.
When extremely slow feed rates are necessary, an entire substrate can be cut in
just one or two passes with a gang saw. Thus, high-speed production is feasible,
and extreme accuracy can be realized. For sawing applications, gang arbors are
available to very precise tolerances, maintaining slot widths within ±0.0002 in
( ±5.08 mm), with a gang pitch tolerance of 0.0002 in, non-cumulative. The
best solution for advanced material and non ferrous material high volume
production operations. Unlike wafer dicing saws that were designed for more
thinner substrate materials. The capabilities of a diamond gang saw are almost
limitless. Gang saws have been proven to provide high production volume at
minimum cost. Multi-Blade cutting system makes all cuts simultaneously and automatically separates end cuts from finished pieces. Gang saws are capable of cutting tubes, rods, and flat glass, quartz, carbon, ceramics, plastics, fiber glass, hybrid and exotic materials and most metals. Normal length tolerance is +/- .002". Squareness is +/- 1.0 degrees. Offering Speed, Precision, & Cost Savings. Designed for machining materials such as Glass, Quartz, Ceramics, and Metals. Cut 10 times faster over conventional sawing methods. Gang saws can cut 400 to 6,000 parts per minute 40/1000 to 59 parts in length, Precision Tolerances + 1/200. Diamond Band Sawing
This process utilizes a flexible, toothed blade is welded into an endless band that rides on wheels driven by two pulleys and is guided through the work cut off or contour. A band saw’s blade is diamond coated by electroplating, a process in which an electrical current deposits the coating onto the blade. This produces a hard, brittle Ni matrix that holds the diamonds in place and permits precise cutting on a variety of materials. A friction saw is a special band saw capable of achieving band velocities of up to 15,000 sfpm or more. Material removal is accomplished in two steps: frictional heat softens the substrate, and the teeth scoop out the molten material. Carbon steel bands are used for flexibility to obtain maximum band life. Method is excellent for cutting extremely hard substrates. Diamond
Grinding Machining operation in which material is removed from the workpiece by means of abrasive points mounted in a matrix in the form of a wheel, stone, belt, paste, compound, or similar application vehicle. Takes various forms: precision surface grinding (creates flat and squared surfaces); cylindrical grinding (process that creates external cylindrical and tapered shapes, fillets, undercuts, etc.); centerless grinding; chamfering; thread and form grinding; tool and cutter grinding; offhand grinding; lapping and polishing (grinding steps using extremely fine grit to create ultra-smooth surfaces); honing; and disc grinding. Grinding steps take several forms: internal, external, and plunge grinding. Usage VolumeYour
diamond blade requirements will greatly vary with your frequency of use and the
number of cuts you need to make. Diamond Blades are generally used for: INDUSTRY / PRODUCTION
RESEARCH & DEVELOPMENT / SAMPLE PREPARATION
Diamond Blade requirements in Research are diverse as fields and researchers that used them. Most researchers & application engineers are primarily concerned about preserving material true micro structure and introducing least amount of damage & deformation possible to material / sample being worked on. Research Applications range from materials sciences, metallogrpahy, advanced materials, advanced/technical ceramics, optics, sample preparation, composites to new and breakthrough fields such as MEMS, Biotechnology and Nano Technology. Typical Research diamond blade users include Universities, Government or Commercial Laboratories, Military Research Facilities, Space & Science Organizations, as well as R & D departments of large organizations. Today, most laboratories and R & D facilities , work with dozens of materials. Frequently each material requires a different sectioning method and sample preparation approach. Selecting the right equipment, consumables, and parameters for your specific material/application will significantly affect your sectioning operation. UKAM Industrial Superhard Tools understands the challenges faced by faced by R & D Organizations and has developed diamond blades, equipment, accessories, and TOTAL SOLUTIONS to address most common R & D applications. We are constantly engaged in R & D and process development ourselves to keep up with increasing demands of the complex / advanced material world / community.
Technical Requirements/Specifications d.) Chipping/Finish Requirements – if you have an application where surface finish and chipping is a critical factor, a sintered (metal bond) diamond blades with a very fine diamond grit may be the best solution. HYBRID Bond diamond blades is another alternative.
e.) Tolerances – if you are using diamond blades for slotting or grooving or your material/product requires specific tolerances, you will need a custom diamond blade specifically designed for your application.
f.) Material Cost – if the material you are cutting cut precious, valuable, or expensive. The diamond blade cost will play a minor role in your cutting operation. It is suggested that you obtain a thin kerf diamond blade to minimize material loss and deformation. It’s always a good idea to have some type of an estimate of target cost and quality per cut. |
COOLANT
TO BE USED
Your capability to use coolant while cutting, will seriously effect your diamond blade selection. Most precision & ultra thin diamond blades in precision diamond sawing operations must be used with coolant. Shorter cutting life, material and cut deformation will result when using blades dry. Electroplated (nickel bonded) diamond blades with coarse mesh size of diamond and some Resin Bond Blades may be used dry (without water) depending on the application (material being cut). UKAM Industrial Superhard Tools does have the capability to manufactured diamond blades to be used without coolant. However, using diamond blades dry is not recommended on most applications. When chance prevails, use all diamond blades with coolant.
DIAMOND / ABRASIVE SELECTION
Diamond is universally recognized as the hardest substance known to man. Diamond is recommended for machining hard & brittle materials, optics, semiconductor packages, advanced materials, composites, ferrous & non ferrous metallic materials from 40 on Rockwell scale and up. Diamond crystals can be synthetically grown in a wide variety of qualities, shapes and sizes. Diamond is grown with smooth crystal faces in a cubo-octahedral shape and the color is typically from light yellow to medium yellow-green. Diamond is also grown to a specific toughness, which generally increases as the crystal size decreases.
Synthetic (Men Made) Diamonds - Most frequently used for most diamond blade manufacturing including sintered (metal bond), resin bond, electroplating (nickel bond). Synthetic diamond is more consistent in particle shape, hardness, and density. Synthetic diamond has replaced natural diamond in most applications because of this ability to tailor-make the diamond for the specific application.
Cubic Boron Nitride (CBN) - often used for machining materials with high metallic content.
Materials recommended for cutting with CBN:
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The ability of a diamond to withstand an impact load is typically referred to as diamond impact strength. Other diamond-related factors, such as crystal shape, size, inclusions and the distribution of these crystal properties, play a role in the impact strength as well. Impact strength can be measured and is commonly referred to as Toughness Index (TI). In addition, crystals are also subjected to very high temperatures during manufacturing and sometimes during the cutting process. Thermal Toughness Index (TTI) is the measure of the ability of a diamond crystal to withstand thermal cycling. Subjecting the diamond crystals to high temperature, allowing them to return to room temperature, and then measuring the change in toughness makes this measurement useful to a diamond tool manufacturer.
The manufacturer must select the right diamond based on previous experience or input from the operator in the field. This decision is based, in part, on the tool's design, bond properties, material to be cut and machine power. These factors must be balanced by the selection of diamond grade and concentration that will provide the operator with optimum performance at a suitable cost.
DIAMOND BLADE VARIABLES
BOND HARDNESS – Ability of the bond matrix to hold diamonds. As the hardness of the bond is increased, its diamond retention capabilities increase as well. However the trade off is slower cutting speed. Life of the diamond blade is usually increased with hardness of its bond matrix. Bonds are designated on their scale of hardness from Soft, Medium, and Hard. There are dozens of variations and classification schemes based on bond degree of hardness or softness. Using diamond blades with optimum bond hardness for your application is important to successful precision diamond sawing operation. Bond matrix that is too soft for the material being cut will release diamond particles faster than needed, resulting in faster wear and shorter diamond blade life. On other hand bond matrix that is too hard will result in much slower cutting speeds and require constant dressing to expose the next diamond layer. As rule of thumb, harder materials such as sapphire and alumina generally require a softer bond. Whereas softer and more brittle materials require a harder bond.
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DIAMOND GRIT
SIZE (Mesh Size) – grit size (mesh size) is generally selected depending on the speed you wish to
operate the cut and surface finish of your material. According to U.S.
Standards, mesh designates the approximate number of sieve meshes per inch. High
Mesh Sizes mean fine grits, and low numbers indicate coarse grits. Diamond Mesh
Size plays a major role in determining the surface finish quality, smoothness,
level of chipping you will obtain, and material microstructure damage you will
obtain. Finer mesh size diamonds such as 220 and 320 grit are much smaller in
size than coarser diamond particles. And will give you a very smooth surface
finish, with minimal amount of chipping on edges. These mesh sizes are usually
used for fine cutting of a full rage of materials such as:
LiNbO3, YVO4,
GaAs, and optical materials. Courser diamond particles such as
80 and 100 grit are much larger in diameter and are frequently used fast
cutting / material removal on more harder materials such as silicon carbide,
zirconia, Al2O3,
stainless steels, and other advanced ceramics and high metallic content
materials. Which do not require a very fine surface finish. |
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The diamond mesh size in a cutting tool also directly relates to the number of crystals per carat and the free cutting capability of the diamond tool. The smaller the mesh size, the larger the diamond crystals, while larger mesh size means smaller diamond. A 30/40 Mesh blocky diamond has about 660 crystals per carat, while a 40/50 Mesh diamond will have 1,700 crystals per carat. Specifying the proper mesh size is the job of the diamond wheel manufacturer. Producing the right number of cutting points can maximize the life of the tool and minimize the machine power requirements. As an example, a diamond tool manufacturer may choose to use a finer mesh size to increase the number of cutting crystals on a low concentration tool, which improves tool life and power requirements.
Diamond Mesh size does have considerable effect on cutting speed. Coarse Diamonds are larger than finer diamonds and will remove more material than finer diamond particles. This means that coarse diamond wheels are more aggressive for material removal than the finer diamond wheels and will cut faster. However, the tradeoff is increase in material micro damage. If you are cutting fragile, more delicate materials then finer mesh size diamond blades are recommended. Diamond mesh size (grit size) should provide maximum removal rate at minimal acceptable finish. Often the desired finish cannot be achieved in a single step/operation. Lapping or polishing may be necessary to produce desired surface finish, as a secondary step in your diamond sawing operation / process.
Recommended diamond mesh size will vary depending on blade type, bond, thickness, machinery used, industry, coolant used, industry, and many other factors
General diamond mesh sizes ranges are recommended and used for metal bond (sintered) 1A1R diamond cut off blades:
COARSE DIAMOND MESH SIZE – 20-60 is used for most masonry, refractory, concrete, and natural stone
MEDIUM DIAMOND MESH SIZE – 80-220 is used for most industrial materials such as glass, porcelain, ceramics, quartz, ultra hard & brittle materials and etc.\
FINE DIAMOND MESH SIZE – 240-400 is used for extremely smooth cutting, grinding and polishing.
If the letters S is included, it designates a mixture of diamond sizes is used in bond. By using a mixture of a coarse and fine diamond mesh sizes. The customer may be able to obtain benefit of fast cutting while maintaining a chip free, smooth cut.
DIAMOND CONCENTRATION - The proportion, and distribution of diamond abrasive particles, also known as concentration. has an effect on overall cutting performance and price of precision diamond blades. Diamond concentration, commonly referred to as CON, is a measure of the amount of diamond contained in a diamond section of drill based upon volume. Diamond concentration is usually defined as: Concentration 100 = 4.4 ct per cm layer volume (mesh size + bond). Based on this definition a concentration of 100 means that the diamond proportion is 25% by volume of diamond layer, assuming at diamond density is 3.52 g/cm3 and 1 ct = 0.2g. Nominal diamond concentration in precision diamond blades range from 0.5 ct/cm3 to 6 ct/cm3. This means diamond concentrations are available from 8 to 135). Selecting the Right Diamond Concentration can be critical in optimizing your Precision Diamond Sawing Operation. Selecting Optimum Diamond Concentration for your application will depend on a large number of factors, such as:
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Diamond Concentration will play a major role in determining the life and cutting speed of your High Precision Diamond Blade. Higher diamond concentration is recommended and usually used for cutting softer and more abrasive types of materials. However, the trade off is significantly slower cutting speed. Low diamond concentration is recommended and widely used for cutting ultra hard and brittle materials. Diamond Concentration is usually determined by the the slowest cutting speed that is acceptable for a specific application. Optimum performance can be achieved when the diamond tool manufacturer utilizes their experience and analytical capabilities to balance diamond concentration and other factors to achieve optimum performance for the tool operator. UKAM Industrial Superhard Tools has the experience & applications laboratory to help you select all the right diamond blade variables for your unique application.
Example of diamond concentration uses on various applications:
25 – Satisfactory of soft nonabrasive materials. May not be satisfactory where production requirements are high
50 – recommended for most materials and satisfactory in production use
100 – for extremely hard dense materials and where smoothness of cut and close tolerances must be met.
Diamond Concentration & Cutting Performance
Today, most Production and R & D facilities use low concentration diamond blades for cutting ceramics, glasses, silicon, carbides, sapphire, and other related semiconductor and optical materials. And use high concentration diamond blades on metals such as stainless steel, aluminum, titanium, pc boards. A new technological breakthrough called SMART CUT™ technology, is making fundamental changes in these beliefs and setting new benchmarks on how diamond blade performance is measured. SMART CUT technology allows the orientation of diamonds inside the metal matrix, so that every diamond is better able to participate in cutting action, By orienting diamonds, SMART CUT™ technology makes diamond concentration only a minor factor in the overall precision diamond equation. Studies and extensive testing shows that diamond concentration in diamond blades manufactured utilizing SMART CUT™ technology plays a no major role in determining overall diamond blade performance.
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Large number of diamonds in a high concentration diamond blade come in contact with material, creating friction, hence considerably slowing down material removal rate. It takes considerable dressing in order to rexpose the next diamond layer. SMART CUT™ technology resolves this problem by making sure that every diamond is in the right place and at the right time, working where you need it most. You get maximum use of diamond and bond. Before this technology was developed, orienting diamonds inside the blade bond matrix was considered impossible. This was one of the main problems faced by diamond tool manufacturers worldwide. Over the decades there have been numerous attempts to solve the diamond and CBN distribution problem. Unfortunately, none of the attempts have been proven effective. Even today 99.8% diamond blade manufacturers still have no way or technology to evenly control and distribute Diamond or CBN particles inside bond matrix, nor properly position them to maximize their machining efficiency. |
Diamond Concentration & CBN (cubic boron nitride) blades
For CBN (cubic boron nitride) concentration is defined by volume. For example V120 = 12% by volume, V180 = 18% by volume.
DIAMOND BLADE THICKNESS – The blade used should be thick enough to provide the strength required for the operation. In high production and roughing operations and on abrasive materials, a heavier blade is necessary. Where machinery is in very good condition and operated properly, a thin blade becomes practical. In very hard dense materials, a thin blade may be required. The thinner the kerf of your diamond blade, faster the speed (RPM) your blade may run, less chipping and heat your blade generates. You will also obtain a smoother and higher quality finish. Thin kerf diamond blades provide the following advantages:
less loss of material
minimum material deformation / preserve true material micro structure
less heat generation
faster cutting speed
less chipping
better finish quality
The trade off is shorter diamond blade life. Find out more... What you should know before you buy your next diamond blade
DIAMOND BLADE OUTSIDE DIAMETER
We usually recommend the smallest diamond blade diameter that will effectively offer the cutting depth required
DIAMOND BLADES SLOTS / SEGMENTS
Sots can be placed around the rim of a steel core in order to permit coolant circulation and chip clearance in the cut. This provides for an improved washing action of kef, reducing abrasive action of the slurry which is otherwise confined to the cutting edge area. Of even greater importance is the reduction of heat because an lager percentage of the coolant is carried to the point of contact. Excess heat will shorten the life of the blade and may cause permanent damage to the steel core or to the bonding of the blade. As a blade diameter and cutting depth increase, the advantage of segmented or slotted blades over continuous rim design is greatly increased.
Segment Spacing Affect on Performance
Closely Spaced Segments - on standard narrow slot cores. Spacing between segments is 1/16" or less. This design is specified where a smooth cut is essential as in cutting glazed tile, glass and ceramic materials. The cutting action will often be smoother than the continuous rim blade with the bonus of increase blade life.
Standard Slot Blades - typically have 1/16" to 3/16" spacing between segments. This recommended for general purpose cutting on materials where chipping and a very smooth surface finish is not essential. This design will tend toward a freer, faster, cutting action and provide better circulation of coolant.
Wide Slot Blades - typically have slot width 5/16" to 3/8" and segment spacing to 1/2" or more. This type provides maximum chip removal and coolant circulation and reduces further the contact area. This design is excellently suited to soft, loosely bonded, abrasive materials. It provides for and allows maximum feed rate.
For more & help on selecting the right diamond blade for your application. Contact UKAM Industrial Superhard Tools Engineering Department at Phone: (661) 257-2288.
SELECTING THE RIGHT DIAMOND BLADE & BOND FOR YOUR APPLICATION
M = Sintered (Metal Bond). R = Resin Bond. H = Hybrid Bond. E = Electroplated (Nickel Bond. MCBN = Metal Bond Cubic Boron Nitride. RCBN = Resin Bond Cubic Boron Nitride. HCBN = Hybrid Bond Cubic Boron Nitride
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Acrylic Glass E Agate M Al-Ni-Co RCBN Alumina (fused) M Aramit Fibre Plastics M Barium Titanate R/H Boron Carbide M Brake Lining E Cemented Carbide
M/R CERAMICS Oxide ceramics, sintered Al2O3 (aluminium oxide) M Al2O3 (tubes) R/H Al2O3 (electronic resistors) E/M Al2O3 (seals) M Carbide Ceramics R/H TIC (titanium carbide)
M NITRIDE CERAMICS Si3N4 (HPSN) silicon nitride R/H Ceramic Tiles M Ceramics Unfired E Chrome Nickel (10% Cr, 90% Ni) RCBN/HCBN CRP (carbon reinforced plastic) M Epoxy Resin Boards E Epoxy Copper-Clad with circuits E Eternite (asbestos-free) E/M Formica (nameplates) E Germanium (semiconductor) M GGG (semiconductor) E/R/H Glass Optical M Glass Fibres (bundeled) E/R Glass Sheet M Glass Ceramics M/R Glass Hard Laminate (cast epoxy) E Glass Fibre Reinforced E Glass Laminates (safety/bullet proof glass) M/H Glass (quartz glass tubes) R/H Glass Wool E Glass (pyrostop) M/H Glass (thick optics) M/H Glass Technical M Glass Fibre Rod E Glass Hard Laminate R/H Granite M Graphite E/M GRP (window sections) E GRP (constructional
sections) M |
GRP (internal thermoplastic ring) E Helopal Panels (plastic) E Hematite M HSS Punches RCBN HSS Hardened RCBN Insulators Ceramic M Lapis Lazuli
M MAGNETIC MATERIALS Ferrites Sintered M/R Ferrites Cast MCBN Rare Earth Magnetic Materials R/H Samarium Cobalt M/R Malachite M Marble M/E Melamine Resin E Metal Coated Ceramics E/M Moybdenum RCBN/H Mycalex (cast stone) M/E Ni Hard Rods RCBN Piezoceramics M Polycarbonate (glass reinforced) E Polystyrene Sheets E Printed Circuit Boards E/M PVC Hard E/M Quartz (fusable) M/R Quartz (synthetic) M Rhodochrosite M Rose Quartz M Sapphire M/R/H Sendust E Silicon (polycrystalline) E Silicon Carbide (pressed & crushed) M Silicon (monocrystalline) M Silicon (semiconductor) M Silicon Nitride R/H Silicon Carbide (ReSiC) R/H Steatite M/R/MCBN Stellite M Tiger’s Eye M Titanium M/R/H Titanium Carbide M Titanium Zirconate M Topaz M Tungsten M/R/E Tungsten Wires M Uranium Dioxide M Uranium M Zirconium M |
Diamond Blades & Cutting Speeds
The RPM’s of the machine spindle should be noted when selecting the right blade specification of your application. So that the blade will be tensioned to run at the operating speed. This will insure a true running blade. Adherence to recommended speed is very important. Improper blade speeds can be rectified in many cases with a pulley change or change in blade diameter. Blade specification can be modified to some degree is speed is not correct, however deviation from recommended SFM should be amended for maximum performance. Make sure the cutting machine you are using is designed or can be adapter to be used for your application. Many machines are designed for other diamond blade applications and may not be ideal for you to use.
Ultra Thin & High Precison Diamond Blades can be used either at low or high speeds. There are advantages and disadvantages of each process. Diamond may break (fracture) at very high speeds, and fall out at very slow speeds. An optimum surface speed / RPM's must be selected to balance out the two disadvantages. Diamond Blade life will usually increase at slower cutting speeds. However the increase in labor costs, utilities costs, depreciation of equipment and other overhead expenses. Will usually offset the saving of diamond blade life and other consumables. Cutting Speed & Surface Finish Quality is often the most important consideration when selecting the right diamond blade for your application. The operator mush choose a balance between life of the blades and their cutting rate. Diamond has a higher impact strength than the material being machined. During the sawing operation, the diamond ruptures the material by impact. Each diamond is able to transfer the electrical power from your cutting machine, into momentum that breaks the material on nano / micro level.
By increasing power on your saw, your diamond blade RPM's and surface speed will increase as well. Hence, each diamond will chip off a smaller amount of material, reducing its impact force on material being machined. And reducing cutting resistance. In theory, by increasing surface speed / RPM's, each diamond should receive a smaller impact force. However, because impact is supported by a smaller volume, the impact force with this low volume is actually increased. There is a higher probability that the diamond particles will break or shatter. Hence, cutting materials at very low surface speeds, creates a large impact force between diamond and material being machined. Although the diamond may not break, the risk that the diamond will be pulled out of diamond blade and causing premature failure of the blade increases.
Understanding Material Hardness & its affect on Diamond Blade Performance
Material Hardness has several meanings. Most common definition for material hardness refers to its ability to resist deformation. Scientifically hardness is defined by energy density (energy per unit volume) required to create strain in material. While there are many ways, scales, and classification schemes to measure material hardness. In this article we will address the most simple explanation.
Mohs scale of Abrasion Hardness is the most simple and well known material hardness measurement and classification methods. In this scale material hardness is measured by scratch test of rubbing each material against another. All material harnesses are arranged in 10 ranks. Each rank is calibrated by a standard mineral. Below find these minerals in their rank of hardness from softest to hardest.
Diamond is the hardest material known to mankind. It can penetrate into any material. Brittle or Soft materials such as granite, advanced ceramics, and copper can be cut by diamond, without diamond particles being broken or exhibiting large pull out. However, when cutting very tough and dense materials such as cemented/tungsten carbide, the contact pressure of each diamond particle must be increased in order to allow diamond to penetrate being cut. The Hardness, Density, & Brittleness of the material being cut will determine whether the diamonds inside the diamond bond matrix need to be blocky and tough enough in order to break (rupture) material by brutal force or if they should be friable & flexible to penetrate the material by sharp points.
Mohs Scale of Hardness
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Hierarchies of Hardness
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Proposed Scale of Hardness for Industrial Materials
| Material | Formula | Mohs Hardness | Knoop Hardness | Rank | Industrial Hardness |
| Graphite | C | 1 - | 12 | 3.6 | 3 |
| Molybdenite | MoS2 | 1 | 17 | 4.1 | 4 |
| Aluminum, annealed | Al | 2 - | 25 | 4.6 | |
| Table Salt | NaCl | 2 | 30 | 4.9 | |
| Gypsum | CaSo4 | 2 | 32 | 5.0 | 5 |
| Silver | Ag | 2+ | 60 | 5.9 | 6 |
| Mild Steel, annealed | Fe | 2+ | 123 | 6.9 | |
| Calcite | CaCO3 | 3 | 135 | 7.1 | 7 |
| Copper | Cu | 4 | 163 | 7.3 | |
| Indium Antimonide | InSB | 4+ | 220 | 7.8 | 8 |
| Magnesia | MgO | 5- | 370 | 8.5 | |
| Glass | Soda lime | 6- | 530 | 9.0 | 9 |
| Tool Steel | Fe | 6+ | 700 | 9.5 | |
| Quartz | SiO2 | 7 | 820 | 9.7 | |
| Chromium | Cr | 7 | 935 | 9.9 | |
| Zirconia | ZrO2 | 8- | 1160 | 10.2 | 10 |
| Cemented WC | WC-Co(8%) | 8- | 1200 | 10.2 | |
| Beryllia | BeO | 8- | 1250 | 10.3 | |
| Silicon | Se | 8 | 1400 | 10.5 | |
| Titanium nitride | TiN | 9- | 1800 | 10.8 | |
| Corundum | Al203 | 9 | 2100 | 11 | 11 |
| Silicon Nitride | Si3N4 | 9 | 2100 | 11 | |
| Tungsten Carbide | WC | 9+ | 2400 | 11.2 | |
| Titanium Carbide | TiC | 9+ | 2470 | 11.3 | |
| Silicon Carbide | SiC | 9+ | 2880 | 11.5 | |
| Boron Carbide | B4C | 9+ | 3000 | 11.6 | |
| Sintered cBN | BN | 10- | 3200 | 11.6 | |
| Cubic boron nitride | BN | 10- | 4800 | 12.2 | 12 |
| Sintered diamond | C | 10- | 5000 | 12.3 | |
| Diamond (Type IIa) | C | 10 | 9000 | 13.1 | 13 |
Evaluating Diamond Blade Performance
The performance of a diamond blade for just about any application / material can be evaluated under various criteria. The importance of any criteria depends on your requirements.
Cutting Life - The life of a diamond blade is determined by the number of cuts it can make. It is fairly difficult to estimate the life of diamond cut. Diamond blade life is affected by various factors such as the application, bond type, blade manufacturer, and experience of user in properly using the blade. The following considerations play a major role in diamond blade life:
hardness and abrasiveness of the material being cut
RPM's (speed) and power of your equipment
amount of pressure used (feed rate)
proper use of coolant (type of coolant, coolant force, & direction)
operator experience (Understanding Proper Diamond Blade Usage Principals and adjusting them as need to better fit their particular application & objectives)
overall age and condition of cutting equipment (precision, accuracy, & repeatability of cutting equipment. As well as Flange Diameter & Maintenance condition of equipment used)
quality, hardness, sharpness, and mesh size of the diamonds
hardness of the bond compared to the material being cut
experience and technology of manufacturer in keeping diamonds in the bond
Surface Finish Quality - The quality of the surface finish is evaluated by the amount of chips generated on the face of the material. Surface finish consists of three basic components: form, waviness and roughness. Although there are more then 100 ways to measure a surface and analyze results. A visual check is the most simple & easiest way of measuring (checking) surface finish quality. The most common scientific way of measuring surface finish quality is using Ra, or Arithmetic Average Roughness. It basically reflects the average height of roughness component irregularities from a mean line. Ra provides a simple value for accept/reject decisions.
Break in time - A diamond blade requires time to break in, to produce relatively chip free performance. The period of time under which this occurs, separates one diamond blade from another.
Frequency of Dressing - The less you have to dress your diamond blade, the better off you will be.
A diamond blade is fundamentally a cutting tool consisting of bond and diamonds. Diamonds are the cutting tool and bond is the medium by which the system is regulated. In purchasing diamond blades, many customers are often concerned about diamond concentration as a dominant factor in pre determining a diamond blades basic value. Diamond concentration may be an important consideration in performance of diamond blades – but it is essential to understand the concentration is not by any means the sole criterion of diamond blade evaluation.
Each diamond blade manufacturer has its own standard for relating diamond concentration to diamond content. In evaluating a diamond blades potential value to you it is important to take into account a variety of cutting variables – only one of which may be diamond content.
Diamond blade cost is usually a minor factor in the grand picture. Whereas labor and overhead costs are more important factors in the total cost picture. Therefore it is important to select a diamond blade that can provide the most performance and productivity, not the lowest blade cost. This product should not be purchased on the basis of price or concentration only, but on the basis of cost per piece cut. Cost performance evaluation is your insurance policy protecting you against taking account of less than all of the variables.
Understanding Diamond Blade Bond Types & their Application
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SINTERED (MEAL BOND) DIAMOND BLADES
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Sintered (Metal bonded) diamond blades diamonds sintered and multiple layers of diamonds impregnated inside the metal matrix. Diamonds are furnaces sintered in a matrix made of iron, cobalt, nickel, bronze, copper, tungsten, alloys of these powders or other metals in various combinations. Metal Bonded Diamond Tools are “impregnated” with diamonds. The compacted materials are then hot pressed or sintered to full density. Heating rate, applied pressure, sintering temperature and holding time, are all controlled according to the matrix composition. This means that selected diamonds are mixed and sintered with specific metal alloys to achieve the best cutting performance possible on any materials such as sapphire, advanced ceramics, optics, glass, granite, tile and etc. The metal bond surrounding the diamonds must wear away to continuously keep re-exposing the diamonds for the diamond tool to continue cutting. Sintered (metal bonded) diamond tools are recommended for machining hard materials from 45 to 75 on Rockwell Scale (5 to 9.5 on mohs scale of hardness). It is more wear resistant and holds diamond well in place, usually producing the highest yield/cutting ratio. As a general rule of thumb, Metal Bond (sintered) diamond blades longer than other diamond bond blades such as resin bond and electroplated (nickel bond) blades. They wear evenly, and are known for their long life & consistency. Sintered (metal bonded) diamond blades are the latest technology available in Diamond Blades. And represent the best value and performance per cut. Metal bond matrix does not protrude diamonds very high and hence usually requires lower cutting speeds than electroplated (nickel bond) and resin bond blades. |
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The letter M designates metal as the type bonding used. Through research in metal powder metallurgy, metal bond has become the most universal bonding material for diamond products. No other bonding utilizes so well the extreme durability of diamonds as an abrasive. It is possible to vary and control the toughness of metal to a great degree while maintaining maximum blade life. SINTERED METAL BOND TYPES This is perhaps the most important factor in selecting the right diamond blade specification for your application/material. The proper metal bond will hold the diamond particles to their full cutting capability, after which they will be released so that new diamonds can take their place. Diamond blades must have a wear factor. The proper wear factor will provide maximum blade life while remaining sharp, fast and smooth cutting. The bond grading indicates the relative strength or holding powder of the bond. Examples of most common sintered (metal bonds) used for cutting application B BOND – a friable bond recommended for very hard materials such as quartz, ferrite, hard ceramics, and glass. It will yield the fastest, smoothest cut M Bond – The general purpose bond for industry. This bond will offer a longer blade life than the A bond when used on the same materials C Bond – A very tough bond for abrasive and soft materials such as carbon, graphite, plastics and fiber glass |
SEM Image of Sintered (metal bond) diamond cut off blade
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RESIN BOND DIAMOND BLADES
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Resin Bond Diamond Blades last less than Sintered (Metal Bond) diamond blades, but more than electroplated (nickel bond) diamond blades. Resin Bond is the softest of all the bonds, frequently used in applications that require a smooth surface finish and minimum amount of chipping. Made from a tough polymer formed to hold the diamond particles in the bond. A resin bond is really tar in a solid form. A resin bond must remain very fragile in order to expose new diamonds. For this reason, strong and high quality diamonds cannot be used in a resin bond. High quality diamonds are harder than a resin bond matrix, and would soon disintegrate the bond that keeps them in place. The diamonds that are used in a resin bond are poor to medium quality. Most of them prematurely disintegrate or fall out of the bond, before they have a chance of being used. This brings about the need for frequent blade dressing, causing the cut to loose its roundness or form. Another disadvantage of Resin bond is its high wear rate, lack of stiffness, and thickness limitation. Resin bond can cut hard & brittle materials fast, but will provide much shorter life. Thinnest blades that can be produced in resin bond is .004". A more durable bond is sintered (metal bond). |
SEM Image of Resin Bond diamond cut off blade
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HYBRID
BOND Diamond
Blades 
Between METAL BOND and RESIN BOND. Designed to replace the conventional resin bond diamond blades. You will find all the advantages of cutting speed and fine finish that you have come to expect in a resin bond, and long life, consistency, aggressiveness, durability, and excellent performance on you look for in a metal bond. Hybrid Bond Diamond Blades are used on finish critical applications, that require a minimum amount of chipping and where no further polishing, lapping, or processing of material is planned. Applications include: Glass/Quartz Tubing, Bk7, Fused Silica, Other ultra brittle materials. Advantages include: Less Chipping, Additional Universality in Application - 1 blade will work in both metal bond and resin bond applications, and Greater Consistency in Performance. Find out more...
| ELECTROPLATED (NICKEL BOND) DIAMOND BLADES |  |
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Electroplated Diamond Blades have a high diamond concentration and give a freer, faster cutting action with minimum heat generation. Diamonds stay on the surface of the cut allowing for fast material removal. Electroplated Diamond Blades last less than metal bond, resin bond, hybrid bond blades and are the least expensive diamond blades available. Perfect for smaller jobs and beginning cutting operations. Just about the only type of diamond blade that may be used dry (without coolant) in a few applications, excellent for cutting very soft, ductile, & gummy materials. Electroplated diamond blades are frequently used for dry cutting (when coolant cannot be used). Electroplated blades a particularly well suited for cutting thermosetting plastics, GRP, pre-sintered and pre-fired (green) materials, electro carbons, graphite, soft ferrites, farinaceous products, deep frozen fish, bones, pc boards, and etc. |
SEM Image of Nickel Bond diamond cut off blade
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What you should know before you buy your next diamond blade?
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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 e-mail: lel@ukam.com |
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