Diamond tool - The Full Wiki

A diamond tool is a cutting tool with diamond grains fixed on the function parts of the tool via some kinds of bond materials or by some other special methods. [ 1 ] The diamonds used in these tools are synthetic or natural industrial diamond of different grain sizes and shapes. Diamond is especially suited to cut highly abrasive materials, such as ceramics, concrete and natural stone.

The bond material may be metal, resin and ceramic. The metal bond materials are mixed with the diamond grains to form diamond segments. which are then welded or cold-pressed onto a backing plate or tool holder that fits different types of machines.

Besides using bond materials, there are also many other methods to fix the diamond grains onto the tools. The methods include electroplating, CVD (Chemical Vapor Deposition), sintering micro-size diamonds in high temperature and high pressure to form PCD, and combining some layers of PCDs with a layer of cemented carbide liner to form PDC. [ 1 ]

Diamond segments are usually a sintered segment with diamond grit mixed into a metal powder, which is blended to get just the right alloy that will wear according to the use of the finished diamond tool. For metal-bonded diamond tools, the bond is one of the prime factors when selecting which tool to use for cutting or grinding a specific material, depending on how hard, or abrasive, the material is. The bond used is what dictates the rate at which the metallic powders wear down and expose new diamond crystals at the surface to maintain what would be considered a abrasive surface.

Different bond strengths are achieved but the metallic powders chosen (alloy mix) and how much heat and pressure are applied to the sintered segment.

Hard bonds are best for soft materials and soft bonds for hard materials. This may seem counterintuitive, but it is because particles of the material being cut or polished provide the wear medium the wears away the bond to expose the diamond grit. Diamond grit is usually not worn out but simply lost when the bond releases them. The more particles the more wear.

For example, when sawing hard materials, a diamond blade with a soft bond would be needed. This means the bonded metallic powders in the segments (teeth) of the diamond blade will wear fast enough to expose diamond crystals and to replace lost grit, exposing new diamond on the cutting edge allowing the tool to continue cutting efficiently. Inversely, to cut a soft abrasive material like asphalt or freshly poured "green" concrete. you would need to use a diamond blade with a hard bond so that the segments do not wear down prematurely releasing the diamond grit without doing enough cutting work, putting the blade to waste.

Resin matrix diamond tools are usually poured into molds with the diamond grains in suspension. The mold shape becomes the tool itself. After removal from the mold, the tools are bonded to a backer. Some have velcro applied to the back of the tool, allowing it to be attached to any hook and loop surface such as concrete grinders .

Diamond_tool: definition of Diamond_tool and synonyms of Diamond_tool (English)

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A diamond tool is a cutting tool with diamond grains fixed on the valid working parts of the tool via some kinds of bond materials or by some other special means. [1]

Diamonds should not be used for cutting steel or iron, as carbon will dissolve into the workpiece and lead to tool wear and work hardening. Three other materials are used for cutting steels where diamond would be used: Cubic boron nitride (cBN, the second hardest material known), aluminum oxide. and silicon nitride tooling may be used.

For metal-bonded diamond tools, the bond is one of the prime factors when selecting which tool to use for cutting or grinding a specific material depending on how hard, or abrasive, the material is. The bond is what decides the rate at which the metallic powders wear down and expose new diamond crystals at the surface to maintain what would be considered a “sharp” edge.

For example, when sawing hard materials, a diamond blade with a soft bond would be needed. This means the metallic powders in the segments (teeth) of the diamond blade wear fast enough to release old, dull crystals, exposing new diamond at the edges to continue cutting efficiently. Inversely, to cut a soft abrasive material like asphalt or freshly poured concrete. you would need to use a diamond blade with a hard bond so that the segments do not wear down prematurely and the blade is not put to waste. Diamond is especially suited to cut highly abrasive materials, such as ceramics.

The diamonds used in these tools are synthetic or natural industrial diamond of different grain sizes and shapes.

Diamond dressers, which consist of single point or multipoint brazed to a steel shank and are used for truing and dressing of grinding wheels, mostly in the automobile industry. After enormous research, the shape and sizes were invented like Grit impregnated, Blade type, Crown type, disc type etc. The advantages of multi point over single point are,

1. The whole diamond can be used unlike single point when the point is blunt you have to reset and after few resetting the diamond is wasted.
2. More accuracy specially in form grinding. blade types are used. Blades consists of elongated diamonds and the thickness is controlled and are available from 0.75 mm to 1.40 mm.
3. Grit type tools are of tough grade and can even use for bench grinders.
4. Since small points are used, these diamonds are of cutting edge with natural points unlike single points are brutted points.
5. Cost will also be very low since small diamonds are used. Diamond value varies more according to size.

Many diamond tools don’t cut like a knife or saw blade, instead they grind. They usually have segments, or teeth, welded to the “cutting” edge of the tool which contain exposed diamond crystals for grinding.

For example, with a diamond blade, the saw operator will push the blade through the material. The blade will begin to cut through the material and the material being cut will begin the wearing process of the diamond blade, at the rate of which the blade advances or the depth at which is being cut. The exposed diamonds will break into smaller pieces when cutting. Hard, dense materials will fracture the diamonds faster. As this happens, the material being cut also wears down the metal bond through abrasion. Highly abrasive materials will wear the bond faster, exposing new diamond crystals to continue cutting .

Polycrystalline diamond (referred to as PCD) is formed in a large High Temperature-High Pressure (HT-HP) press, as either a diamond wafer on a backing of carbide, or forming a 'vein' of diamond within a carbide wafer or rod.

Most wafers are polished to a mirror finish then cut with an Electric Discharge Machine (EDM) into smaller workable segments that are then brazed onto the sawblade, reamer, drill or other tool. Often they are EDM machined and/or ground an additional time to expose the vein of diamond along the cutting edge. Today these tools are mostly used for machining of nonmetallic and nonferrous materials.

The grinding operation is combined with EDM for several reasons. For example, according to Modern Machine Shop, the combination allows a higher material removal rate and is therefore more cost effective. Also, the EDM process slightly affects the surface finish. Grinding is used on the affected zone to remove the effected area and provide a finer final surface. Along the same lines, Beijing Institute of Electro-Machining attributes a finer shaping and surface geometry to the compilation of the two processes into one.

The process itself is accomplished by combining the two elements each individual process into one wheel. The diamond graphite wheel accomplishes the task of grinding while the graphite ring around the existing wheel serves as the EDM portion. However, since diamond is not a conductive material, the bonding in the PCD work piece must be ample enough to generate the conductivity necessary for the EDG process to work.

Diamond pastes are used for polishing materials that require a mirror finish. Often used in metallurgical specimens. Also used widely in carbide dies, carbide seals, spectacle glass industry and also for polishing of diamonds.

Diamond powder deposited through electroplating are used in form of files, or small grinding applications. It has also found a new use of making nail files for nails.

SPDT, or Single Point Diamond Turning, utilizes a solid, flawless diamond as the cutting edge. The single crystalline diamond can be natural or synthetic, and is sharpened to the desired dimensions by mechanical grinding and polishing. The cutting edge of most diamond tools is sharp to tens of nanometers, making it very effective for cutting non-ferrous materials to high resolution. SPDT is a very accurate machining process used to create finished aspherical and irregular optics without the need for further polishing after completion. The most accurate machine tool in the world, the LODTM at Lawrence Livermore National Labs, has a profile accuracy estimated at 23 nanometers, while most machines seek a roughness within that deviation.

PCD tools are used extensively in automotive and aerospace industries. They are ideal for speed (9000+ SFM) machining in tough and abrasive aluminum alloys, and high abrasion processes such as carbon fiber drilling, and ceramics. The diamond cutting edges make them last for extended periods without having to shut down processes to replace tooling. High volume processes, tight tolerances, and highly abrasive processes are ideal for diamond tooling.

SPDT is used for optics, and for flat surfaces where both surface finish and irregularly high dimensional accuracy are required when lapping would be uneconomical or impractical.

The grinding method is ideal for materials that do not cut but are ground; stone, cement, carbides are all difficult to process normally. Often this makes a diamond abrasion method necessary.

There are a lot of aspects where the diamond tools could be used. In medicine, the Venezuelan scientist Humberto Fernandez Moran invented the diamond scalpel for applications in delicated surgeries. In industry, they are commonly used for cutting a wide variety of very hard construction materials, including reinforced and cured concrete. all types of brick and cinder blocks. dense metals, rebar. asphalt. granite. marble. travertine. porcelain. and many other types of materials which cannot be cut with ordinary cutting tools.

• For more detailed explanation of how to use a diamond drilling holesaws see Diamond drilling porcelain

• Diamond saw blades: For high-speed gas powered cut-off saws, walk behind saws, handheld grinders, bridge saws, table saws, tile saws and other types of saws.
• Diamond tipped grinding cups: Used commonly on hand grinders for grinding concrete or stone.
• Diamond tipped core bit or holesaw: Hollow steel tube with diamond tipped segments for drilling holes through concrete walls in the construction industry, porcelain tiles or granite worktops in the domestic industry, or also used for sample core extractions in the mining industry.
• PCD tool insert: Used in machine tools for ceramics and high speed aluminum machining.
• SPD tool insert: Used in turning centers for optics and precision surfaces.

• Concave blade: For cutting curves in countertops to install sinks or sculpt statues.
• TuckPointers: Thick diamond blades for restoration - grinding and replacing mortar.
• Crack chasers: Thick V-shaped diamond blades for repairing cracks in concrete.
• Polishing pads: Pads with diamond crystals for polishing marble and other fine stone.
• Diamond wire cutting. wire with diamond crystals for cutting.
• Diamond saw chain for cutting stone, concrete and brick with a special chainsaw .

Diamond tools

Diamond tools are classified as either wet cutting or dry cutting, but they all work better wet. Wet is messy, dry is dusty!

Cutting wet, that is with a water hose either attached to the machine or having one spraying lightly on the machine and surface being cut is:-

• Better for the actual blade wear, so that it is cheaper than cutting dry.
• The reason for this is that the water cools the blade. There is an enormous amount of heat generated by the cutting action.
• The water produces a cement slurry that is very messy, clean it up while it is still wet, clean and clean it again.
• If that slurry dries it is almost as hard to get ride of as cement itself.
• Cutting wet does not produce dust, so for safety reasons in this respect it is better.
• The main safety concern with cutting wet is with electricity.
• You must use ELD safety boxes, see my power tool safety page for more on these.
• A lot of the newer machine have the safety device either built into the machine, or in the machine's own power cord.

Dry cutting is in general only done in short burst, to let the dust settle and to cool the blade.

• Because of the heat generated in the tool, generally the process is slower. More stops to let the thing cool off.
• There is an enormous amount of dust produced. Making it mandatory to use good quality dust masks and also eye protection.
• When grinding dry,I go for a rubber replaceable cartridge type dust mask, like a spray painting one.
• Don't use the paper throw away ones, as some of the grinding dust is very fine.
• I've seen guys take a paper mask off and have a rim of white around their nose.
• Dry cutting dust is also a killer for the machine itself. For example an angle grinder used by ceramic tilers sucks in the fine dust with the cooling air. This dust cuts out the bearings in the machine quick smart.
• The dry tools typically have slots designed to air cool the cutting surface.

The first thing learnt when I bought my large concrete saw was to take it easy, don't force the machine.

• As soon as you see sparks coming off the blade, slow down!
• This means that diamond is being used too quickly and is being wasted.
• There is an exception to this and that is when you are cutting through rebar.

Below is my 235mm (9 1/4") Makita angle grinder with a diamond concrete saw blade in it.

I use it for cutting up to about 30mm deep in concrete. You can see the tide mark on the blade.

Any deeper cutting requires a lot of tedious work, for that I hire a larger machine.

Diamond Tools

Sterling offers a complete range of diamond tools for Single-Point Diamond Turning (SPDT).??Flexibility: As technology changes, Sterling ensures that each client has the right diamond tools for all requirements. We provide standard and customized (process-specific) diamond tool solutions for all R&D and production needs.

• Natural and synthetic single crystal diamonds
• Traditional solid shank or insert systems (in which the diamond is vacuum brazed to a tungsten insert)
• Controlled or non-controlled waviness options
• Conical or cylindrical clearance options
• Custom tooling designs
• Rapid, high quality re-lap services in North America, Europe and Far East
• Flexible, custom, managed programs to lease diamond tools rather than invest in tool inventories

Quality. The ultimate precision in lathing is derived from a 2-axis machine design. This provides both the greatest precision and maximum rigidity in the machine tool. 2-axis machines require controlled waviness tool designs for the finishing tool only. If there is error in a diamond tool form, this translates (one to one) directly into geometric error in the surface of a machined part, so tool quality is of the highest importance to ensure good form. ?Diamond tools are made under ISO 9001:2000 manufacturing controls and inspection procedures, to international industry standards.

Tool life. Precise craftsmanship and quality control ensure that each diamond is cut and oriented for maximum life. Sterling works with clients to ensure

• high-quality, wear-resistant tools
• good tool care procedures
• regular relapping schedules
• help and trouble-shooting for any process problems which might shorten diamond tool life
• managed tool programs
• CNC controlled spray-misting attachments, as a machine option, to prolong diamond life and enhance surface finish

Relapping. Sterling offers diamond tool relapping or repair at several centers world-wide (North America, Europe, Far East). Rapid turn-around and excellent precision work ensure that all tools return promptly, having been relapped/repaired to the highest standards.

Value. Diamond tools are an on-going cost in manufacturing, so Sterling takes care to ensure that all tools offer exceptional value for money, without compromising quality and service.

WN - diamond tool

CHARLOTTE. N.C.. Oct. 21, 2015 /PRNewswire / -- Husqvarna – the world's leading manufacturer of.

A diamond tool is a cutting tool with diamond grains fixed on the functional parts of the tool via a bonding material or another method. As diamond is a superhard material. diamond tools have many advantages as compared with tools made with common abrasives such as corundum and silicon carbide .

Diamond is the hardest material on the earth, and its hardness is much higher than corundum and silicon carbide. Diamond also has high strength, good wear resistance and low friction coefficient. So when used as an abrasive. it has many obvious advantages over the common abrasives.

Diamond can be used to make grinding tools, which have following advantages:

There are thousands kinds of diamond tools. They can be categorized by their manufacturing methods and their uses.

According to their manufacturing methods or bond types, diamond tools can be categorized to the following way:

If categorized by use, there are diamond grinding tools, diamond cutting tools (e.g. diamond coated twist drill bits), diamond drilling tools, diamond sawing tools (e.g. diamond saw blades ), diamond drawing dies, etc.

Diamond Tool - D

Kane, Dalsimer Kane Sullivan And Kurucz

1. A diamond tool comprising a diamond with a cutting edge, a metal connecting block and a tool shaft with a front end, the diamond being brazed to the metal connecting block which together with the diamond is encased in a sinter mass which is brazed to the front end of the tool shaft, wherein the connecting block at its side opposite of the diamond has a brazing face lying free of the sinter mass also being fixedly brazed to the front end of the tool shaft.

2. Diamond tool according to claim 1, having a brazing material used for bonding the diamond to the connecting block wherein the brazing material has a melting point which is substantially higher than the sintering temperature of the sinter material and the melting point is between 900°-1200° C.

3. Diamond tool according to claim 1, wherein the upper face of the connecting block is substantially smaller than the contacting lower face of the diamond.

4. Diamond tool according to claim 1, wherein the connecting block has a cylindrical shape.

5. Diamond tool according to claim 1, wherein grooves are provided in the connecting block at the upper side directed to the diamond.

6. Diamond tool according to claim 5, wherein the grooves form a cross.

7. Diamond tool according to claim 1, wherein the block is made of a suitable metallic material, the thermal coefficient of expansion of which differs only a small amount from that of diamond.

Description:

The invention relates to a diamond tool having a diamond with a cutting edge, which diamond is encased in a sinter mass which is brazed to the front end of a tool shank.

During manufacture of known diamond tools of this type the diamond is first enclosed in a plug-shaped encasing of for example sintered bronze, whereafter the sinter plug is finished in such a manner that it can be brazed on a tool holder. Subsequently, the front end of the diamond is made free by filing so that a cutting edge of the desired shape can be ground on the diamond.

Such diamond tools are used for example for turning high quality surfaces of metal mirrors and memory discs for computers, for example. As to the quality to be obtained of the surfaces machined with such tools, among others the quality of the cutting edge of the tool, a vibration free rotation of the machine and a clearance free and rigid grip of the tool are of essential importance.

With the further development of the art the requirements which are made upon the machined surfaces are increased still further. For example, the possible recording density on the surface of said computer memory discs is determined among others by the obtainable surface quality of the discs. Practice has shown that problems occur in this respect at the use of said conventional diamond tools, which problems are caused by an insufficient resistance to vibrations of the diamond in the diamond tool. Although the diamond is enclosed in a sintered encasing, there is no bonding between the contacting surfaces of the encasing and the diamond. Therefore, the stability of the diamond during the cutting is dependent on the presence and the magnitude of the clamping forces between the sintered material of the encasing and diamond. In practice it is difficult to guarantee a sufficient clamping of the diamond after sintering the sinter mass. Moreover, during the finishing and brazing of the sinter plug and during grinding the diamond thermical and mechanical circumstances occur which make a good clamping of the diamond more uncertain. Thereby, it can easily happen that the diamond will get into vibration during operation due to the occurring cutting forces or even shows clearance in its encasing, for example in the range of hundredths or tenths or a micrometer. Such phenomena can of course not be compensated by taking measures on the machine.

The invention aims to provide a sintered diamond tool of the above-mentioned kind which obviates these imperfections of the known sintered tools.

To this end, the diamond tool according to the invention is characterized in that the diamond is brazed to a metal connecting block which is encased in the sinter mass together with the diamond. By this connecting block fixedly brazed to the diamond not only the engaging surface between the sinter mass and the component to be clamped consisting of the diamond and said block, is substantially increased but it also appears that the sinter mass is able to perfectly hold the metal of this block in particular if it consists of molybdenum. It appeared that in this manner an enclosing of the component consisting of the connecting block and the diamond which is sufficiently rigid and clearance free for many applications, is obtained, wherein an improved vibration damping is also obtained.

In order to obtain a still better bonding of the diamond desired in certain cases, according to the invention it is preferred that the connecting block has at its lower side opposite of the diamond a brazing face lying free of the sinter mass, with which brazing face the block itself is fixedly brazed to the tool shaft also. In this manner a fixed and rigid connection is obtained between the diamond and the tool shaft, while further the sinter mass enclosing the diamond and the connecting block damps possibly occurring vibrations by friction with the surface thereof.

The brazing material used for bonding the diamond to the connecting block should have a melting point which is substantially higher than the sintering temperature of the sinter material and for example, amounts up to approximately 900°-1200° C. Such brazing materials for diamond are known per se and for example consist of a suitable alloy of copper, silver and titanium or of gold to which 4% tantalum is added. In this manner the diamond can first be brazed to the block and subsequently together with this block be encased in a sinter plug without affecting the brazed bond during sintering. In addition to the side of the cutting edge of the diamond to be ground the sinter plug is also filed away at its lower side until the lower surface of the connecting block lies free and can be brazed to the tool shaft together with the sinter mass. For this last mentioned brazing operation the brazing material normally used for this purpose can be applied, the melting point of which is lower and amounts up to maximum approximately 600° C.

According to a favourable embodiment of the invention grooves are provided in the connecting block at the upper side directed to the diamond. Thereby a difference between the thermal coefficient of expansion of the diamond and the material of the connecting block can be accommodated.

According to another embodiment it is however also possible to make the block of a material like molybdenum or a hard metal, the thermal coefficient of expansion of which differs only a little from the same of diamond.

A further advantage of the construction of the diamond tool according to the invention is that in certain cases a smaller diamond can suffice than at the conventional tools because a smaller contacting surface between the sinter mass and the diamond is required.

The invention will be further explained by reference to the drawing, in which an embodiment of the diamond tool of the invention is shown.

FIG. 1 shows a top view of the tool.

FIG. 2 shows a side view of the tool of FIG. 1.

FIG. 3 is a section according to the line III--III of FIG. 1 on a larger scale.

A diamond tool shown comprises a tool shaft 1 of conventional construction, in which at the front side a recessed, stepped seat is provided which is bounded by a horizontal bottom face 2 and a vertical end face 3.

The tool shaft 1 carries at its front side a diamond 4 of conventional shape with a ground cutting edge 5 and obliquely outwardly extending sides and a back side. The diamond 4 is brazed to a cylindrical connecting block 6 by using a brazing material with a high melting point of approximately 900°-1200° C. As brazing material a suitable alloy of copper, silver and titanium is used although other brazing materials can also be used, like for example an alloy consisting of 96% gold and 4% tantalulum.

The assembly of the diamond 4 and the block 6 is subsequently encased in a sinter mass 7 of for example sintered bronze, wherein this mass not only encloses the sides and the back side of the diamond 4 but also joins a large portion of the lower face of the diamond as, as shown, the upper face of the cylindrical block 6 is substantially smaller than the lower face of the diamond. By a suitable machining the formed sinter plug is shaped in such a manner that it fits in the seat 2, 3 of the tool shaft 1, wherein the lower face of the sinter mass is removed thus far that the lower face of the block 6 has become free. After grinding of the cutting edge 5 of the diamond 4 which edge 5 was also made free, the obtained assembly is fixedly brazed in the seat 2, 3 by using a suitable conventional brazing material with a melting point lower than the sintering temperature of the sinter mass. The lower face of the connecting block 6 is directly brazed to the bottom face 2 of the seat.

In the embodiment shown grooves 8 are made in a cross-wise manner in the upper portion of the connecting block 6 in order to provide for a compensation possibility for a diffence between the thermal coefficient of expansion of the diamond and the material of the block 6. However, it is also possible to make the connecting block 6 out of a material, like for example molybdenum, the thermal coefficient of expansion of which differs only a little from the same of diamond, in which case the grooves 8 may be omitted.

By the above-described construction the connecting block 6 forms a fixed and rigid connection between the diamond 4 and the tool shaft 1, whereby the diamond is immovably held on the shaft. The sinter mass joins the diamond and the block along a great surface, whereby a good damping of possibly occurring vibrations in the diamond is obtained.