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An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific While finishing a material often means polishing it to gain a smooth, reflective surface it can also involve roughening as in satin, matte or beaded finishes. Polishing is the process of creating a smooth and shiny surface by using rubbing or a chemical action leaving a surface with significant Specular reflection and minimal

Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications. This gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, and sanding (see abrasive machining). Polishing is the process of creating a smooth and shiny surface by using rubbing or a chemical action leaving a surface with significant Specular reflection and minimal Cutting is the separation of a physical object or a portion of a physical object into two portions through the application of an acutely directed force Drilling is the process of using a Drill bit in a Drill to produce cylindrical holes in solid materials such as wood or metal Sharpening is the process of creating or refining a sharp edge of appropriate shape on a tool or implement designed for cutting Abrasive Paper is a form of Paper where an Abrasive material has been fixed to its surface Abrasive Machining is a manufacturing process where material is removed from a workpiece using a multitude of small Abrasive particles (For simplicity, "mineral" in this article will be used loosely to refer to both minerals and mineral-like substances whether man-made or not. )

Files act by abrasion but are not classed as abrasives as they are a shaped bar of metal. A file (or hand-file) is a Hand Tool used to shape Material by cutting However, diamond files are a form of coated abrasive (as they are metal rods coated with diamond powder).

Abrasives give rise to a form of wound called an abrasion or even an excoriation. An excoriation is an erosion or destruction of the Skin by mechanical means which appears in the form of a scratch or abrasion of the skin Abrasions may arise following strong contract with surfaces made things such as concrete, stone, wood, carpet, and roads, though these surfaces are not intended for use as abrasives. Concrete is a construction material composed of Cement (commonly Portland cement) as well as other cementitious materials such as Fly ash and Slag Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs A carpet is any loom-woven felted textile or grass floor covering A road is an identifiable route, way or path between two or more places.

Contents

Mechanics of abrasion

Abrasives generally rely upon a difference in hardness between the abrasive and the material being worked upon, the abrasive being the harder of the two substances. However, this is not necessary as any two solid materials that repeatedly rub against each other will tend to wear each other away (such as softer shoe soles wearing away wooden or stone steps over decades or centuries or glaciers abrading stone valleys). "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period.

Typically, materials used as abrasives are either hard minerals (rated at 7 or above on Mohs scale of mineral hardness) or are synthetic stones, some of which may be chemically and physically identical to naturally occurring minerals but which cannot be called minerals as they did not arise naturally. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material (While useful for comparative purposes, the Mohs scale is of limited value to materials engineers as it is an arbitrary, ordinal, irregular scale. ) Diamond, a common abrasive, for instance occurs both naturally and is industrially produced , as is corundum which occurs naturally but which is nowadays more commonly manufactured from bauxite. In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in Corundum (from Tamil kurundam குருந்தம் or kuruvindam குருவிந்தம் is a Crystalline form of Bauxite is the most important Aluminium Ore. It consists largely of the minerals Gibbsite Al(OH3 Boehmite γ-AlO(OH and [1] However, even softer minerals like calcium carbonate are used as abrasives, such as "polishing agents" in toothpaste. Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3

Grit size ranging from 2 mm (the large grain) (about F 10 using FEPA standards) to about 40 micrometres (about F 240 or P 360).
Grit size ranging from 2 mm (the large grain) (about F 10 using FEPA standards) to about 40 micrometres (about F 240 or P 360).

These minerals are either crushed or are already of a sufficiently small size (anywhere from macroscopic grains as large as about 2 mm to microscopic grains about 0. 001 mm in diameter) to permit their use as an abrasive. These grains, commonly called grit, have rough edges, often terminating in points which will decrease the surface area in contact and increase the localised contact pressure. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface The abrasive and the material to be worked are brought into contact while in relative motion to each other. Force applied through the grains causes fragments of the worked material to break away while simultaneously smoothing the abrasive grain and/or causing the grain to work loose from the rest of the abrasive.

Some factors which will affect how quickly a substance is abraded include:

Abrasive minerals

Abrasives may be classified as either natural or synthetic. When discussing sharpening stones, natural stones have long been considered superior but advances in material technology are seeing this distinction become less distinct. Many synthetic abrasives are effectively identical to a natural mineral, differing only in that the synthetic mineral has been manufactured rather than been mined. Impurities in the natural mineral may make it less effective.

Some naturally occurring abrasives are:

Some abrasive minerals (such as zirconia alumina) occur naturally but are sufficiently rare or sufficiently more difficult/costly to obtain such that a synthetic stone is used industrially. Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 Emery is a very hard rock type used to make abrasive powder It largely consists of the mineral Corundum ( Aluminum oxide) mixed with other species such as the iron-bearing In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in Novaculite is a form of Chert or Flint found in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift Pumice is a textural term for a volcanic rock that is a solidified frothy lava composed of highly microvesicular glass Pyroclastic with very thin translucent Iron(III oxide —also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply Rust —is Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Zirconia alumina is commonly-used as a Sand-blasting medium It is typically used as an Abrasive in Casting and Foundry processes These and other artificial abrasives include:

Manufactured abrasives

Abrasives are shaped for various purposes. Borazon, a Boron nitride Allotrope, is the fourth hardest substance after Aggregated diamond nanorods, Ultrahard fullerite, and Diamond Boron nitride ( BN) is a binary chemical compound, consisting of equal numbers of Boron and Nitrogen atoms The word ceramic is derived from the Greek word κεραμικός ( keramikos) Corundum (from Tamil kurundam குருந்தம் or kuruvindam குருவிந்தம் is a Crystalline form of Dry ice is solid Carbon dioxide. It is commonly used as a versatile cooling agent Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many Silicon carbide ( is a compound of Silicon and Carbon bonded together to form Ceramics but it also occurs in nature as the extremely rare mineral Natural abrasives are often sold as dressed stones, usually in the from of a rectangular block. Both natural and synthetic abrasives are commonly available in a wide variety of shapes, often coming as bonded or coated abrasives, including blocks, belts, discs, wheels, sheets, rods and loose grains.

Bonded abrasives

Assorted grinding wheels as examples of bonded abrasives.
Assorted grinding wheels as examples of bonded abrasives.
A grinding wheel with a reservoir to hold water as a lubricant and coolant.
A grinding wheel with a reservoir to hold water as a lubricant and coolant.

A bonded abrasive is composed of an abrasive material contained within a matrix, although very fine aluminium oxide abrasive may comprise sintered material. The matrix or groundmass of rock is the fine-grained mass of material in which larger grains or Crystals are embedded Sintering is a method for making objects from powder, by heating the material (below its Melting point - solid state sintering until its particles adhere This matrix is called a binder and is often a clay, a resin, a glass or a rubber. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and Resin, not to be confused with Rosin, is a Hydrocarbon Secretion of many Plants particularly coniferous trees. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many This mixture of binder and abrasive is typically shaped into blocks, sticks, or wheels. The most usual abrasive used is aluminium oxide. Also common are silicon carbide, tungsten carbide and garnet. Silicon carbide ( is a compound of Silicon and Carbon bonded together to form Ceramics but it also occurs in nature as the extremely rare mineral Tungsten carbide, WC, or tungsten semicarbide, W2C, is a chemical compound containing Tungsten and Carbon, similar The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives Artificial sharpening stones are often a bonded abrasive and are readily available as a two sided block, each side being a different grade of grit.

Grinding wheels are cylinders that are rotated at high speed. A grinding wheel is an expendable wheel that is composed of an Abrasive compound While once worked with a foot pedal or hand crank, the introduction of electric motors has made it necessary to construct the wheel to withstand greater radial stress to prevent the wheel flying apart as it spins. Similar issues arise with cutting wheels which are often structurally reinforced with impregnated fibres. A grinding wheel is an expendable wheel that is composed of an Abrasive compound High relative speed between abrasive and workpiece often makes necessary the use of a lubricant of some kind. Traditionally they were called coolants as they were used to prevent frictional heat build up which could damage the workpiece (such as ruining the temper of a blade). A coolant is a fluid which flows through a device in order to prevent its overheating transferring the heat produced by the device to other devices that utilize or dissipate it Tempering is a Heat treatment technique for metals and Alloys In Steels tempering is done to "toughen" the metal by transforming brittle Some research suggests that the heat transport property of a lubricant is less important when dealing with metals as the metal will quickly conduct heat from the work surface. More important are their effects upon lessening tensile stresses while increasing some compressive stresses and reducing "thermal and mechanical stresses during chip formation". [2]

Various shapes are also used as heads on rotary tools used in precision work, such as scale modelling. A rotary tool is a hand held Power tool with a variety of rotating accessory bits and attachments that can be used for cutting carving sanding polishing and many other applications A scale model is a representation or copy of an object that is larger or smaller than the actual size of the object.

Bonded abrasives need to be trued and dressed after they are used. Dressing is cleaning the waste material (swarf and loose abrasive) from the surface and exposing fresh grit. Depending upon the abrasive and how it was used, dressing may involve the abrasive being simply placed under running water and brushed with a stiff brush for a soft stone or the abrasive being ground against another abrasive, such as aluminium oxide used to dress a grinding wheel.

Truing is restoring the abrasive to its original surface shape. Wheels and stones tend to wear unevenly, leaving the cutting surface no longer flat (said to be "dished out" if it is meant to be a flat stone) or no longer the same diameter across the cutting face. This will lead to uneven abrasion and other difficulties.

Coated abrasives

A German sandpaper showing its backing and FEPA grit size.
A German sandpaper showing its backing and FEPA grit size. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe.
Main article: Coated abrasive

A coated abrasive comprises an abrasive fixed to a backing material such as paper, cloth, rubber, resin, polyester or even metal, many of which are flexible. Coated abrasives are made of abrasive grains adhered to the surface of flexible or semi-flexible backings such as Paper, cloth vulcanized fiber Plastic films Paper is thin material mainly used for writing upon printing upon or packaging A textile is a flexible material comprised of a network of natural or artificial Fibres often referred to as thread or Yarn. Polyester is a category of Polymers which contain the Ester Functional group in their main chain The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Sandpaper is a very common coated abrasive. Abrasive Paper is a form of Paper where an Abrasive material has been fixed to its surface Coated abrasives are commonly the same minerals as are used for bonded abrasives. A bonding agent (often some sort of adhesive or resin) is applied to the backing to provide a flat surface to which the grit is then subsequently adhered. A woven backing may also use a filler agent (again, often a resin) to provide additional resilience.

Coated abrasives may be shaped for use in rotary and orbital sanders, for wrapping around sanding blocks, as handpads, as closed loops for use on belt grinders, as striking surfaces on matchboxes, on diamond plates and diamond steels. Belt grinding is a machining method to process metals and other materials with the aid of coated Abrasives The basic difference between belt grinders and Belt A match is a consumable Tool for lighting a Fire under controlled circumstances on demand Diamond plate is a type of metal stock with a regular pattern of raised diamonds or lines Diamond tools, though for cutting, are often abrasive in nature. A diamond tool is a Cutting tool which contains Diamond segments bonded to a base material for cutting through a wide variety of non-ferrous materials

Other abrasives and their uses

Here the abrasiveness of toothpaste is detailed by its Relative Dentin Abrasivity (RDA)
Here the abrasiveness of toothpaste is detailed by its Relative Dentin Abrasivity (RDA)

Sand, glass beads, metal pellets and dry ice may all be used for a process called sandblasting (or similar, such as the use of glass beads which is "bead blasting"). Dentin ( BE: dentine) is a calcified tissue of the body and along with enamel, Cementum, and pulp is one of the four Dry ice is solid Carbon dioxide. It is commonly used as a versatile cooling agent Sandblasting or Bead blasting is a generic term for the process of smoothing shaping and cleaning a hard surface by forcing solid particles across that surface at high speeds Dry ice will sublimate meaning that there is no residual abrasive left afterwards.

Cutting compound used on automotive paint is an example of an abrasive suspended in a liquid, paste or wax, as are some polishing liquids for silverware and optical media. Cutting compound consists of an Abrasive suspended in a Paste. The liquid, paste or wax acts as a binding agent that keeps the abrasive attached to the cloth which is used to as a backing to move the abrasive across the workpiece. On cars in particular, wax may serve as both a protective agent by preventing exposure of the paint of metal to air and also act as an optical filler to make scratches less noticeable. Toothpaste contains calcium carbonate or silica as a "polishing agent" to remove plaque and other matter from teeth as the hardness of calcium carbonate is less than that of tooth enamel but more than that of the contaminating agent. Toothpaste is a Paste or Gel Dentifrice used to clean and maintain the aesthetics and health of Teeth. Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material Tooth enamel is the hardest and most highly mineralized substance of the body and with Dentin, Cementum, and dental pulp is one of the four major

Very fine rouge powder was commonly used for grinding glass, being somewhat replaced by modern ceramics, and is still used in jewellery making for a highly reflective finish. Iron(III oxide —also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply Rust —is

Cleaning products may also contain abrasives suspended in a paste or cream. They are chosen to be reasonably safe on some linoleum, tile, metal or stone surfaces. Linoleum is a Floor covering made from solidified Linseed oil (linoxyn in combination with Wood flour or cork dust over a Burlap or Canvas A tile is a manufactured piece of hard-wearing material such as Ceramic, stone, metal or even Glass. However, many laminate surfaces and ceramic topped stoves are easily damaged by these abrasive compounds. A laminate is a material constructed by uniting two or more layers of material together Even ceramic/pottery tableware or cookware can damage these surfaces, particularly the bottom of the tableware which is often unglazed in part or in whole and acts as simply another bonded abrasive. [3]

Metal pots and stoves are often scoured with abrasive cleaners, typically in the form of the aforementioned cream or paste or of steel wool. Steel wool or 'wire wool' is a bundle of strands of very fine soft Steel filaments used in finishing and repairing work to polish wood or metal objects as well as for

Human skin is also subjected to abrasion in the form of exfoliation. Abrasives for this can be much softer and more exotic than for other purposes and may include things like almond and oatmeal. The Almond ( Prunus dulcis, syn Prunus amygdalus Batsch Amygdalus communis L Breakfast cereal health benefits There has been increasing interest in oatmeal in recent years due to its beneficial health effects [4] Dermabrasion and microdermabrasion are now rather commonplace cosmetic procedures which use mineral abrasives. Dermabrasion is a cosmetic medical procedure in which the surface of the epidermis of the Skin (the Stratum corneum) is removed by abrasion Microdermabrasion (often referred to as Microderm is a family of cosmetic procedures popular in Day spas doctors' practices and medical spas in which

Scratched compact discs and DVDs may sometimes be repaired through buffing with a very fine compound, the principle being that a multitude of small scratches will be more optically transparent than a single large scratch. DVD (also known as " Digital Versatile Disc " or " Digital Video Disc " - see Etymology)is However, this does take some skill and will eventually cause the protective coating of the disc to be entirely eroded (especially if the original scratch is deep), after which the data surface will be destroyed if abrasion continues.

Choice of abrasive

The shape, size and nature of the workpiece and the desired finish will influence the choice of the abrasive used. A bonded abrasive grind wheel may be used to commercially sharpen a knife (producing a hollow grind), but an individual may then sharpen the same knife with a natural sharpening stone or an even flexible coated abrasive (like a sandpaper) stuck to a soft, non-slip surface to make achieving a convex grind easier. The grind of a blade refers to the shape of the cross-section of the blade The grind of a blade refers to the shape of the cross-section of the blade Similarly, a brass mirror may be cut with a bonded abrasive, have its surface flattened with a coated abrasive to achieve a basic shape, and then have finer grades of abrasive successively appied culminating in a wax paste impregnated with rouge to leave a sort of "grainless finish" called, in this case, a "mirror finish".

Also, different shapes of adhesive may make it harder to abrade certain areas of the workpiece. Health hazards can arise from any dust produced (which may be ameliorated through the use of a lubricant) which could lead to silicosis (when the abrasive or workpiece is a silicate) and the choice of any lubricant. Silicosis (also known as Grinder's disease and Potter's rot) is a form of Occupational lung disease caused by inhalation of crystalline Silica For the Artificial intelligence Androids of the 1990s Science fiction series Space Above and Beyond, see Silicate (AI Besides water, oils are the most common lubricants. These may present inhalation hazards, contact hazards and, as friction necessarily produces heat, flammable material hazards. [5]

An abrasive which is too hard or too coarse can remove too much material or leave undesired scratch marks. Besides being unsightly, scratching can have other, more serious effects. Excessive abrasion or the presence of scratches may:

A finer or softer abrasive will tend to leave much finer scratch marks which may even be invisible to the naked eye (a "grainless finish"); a softer abrasive may not even significantly abrade a certain object. A softer or finer abrasive will take longer to cut as tends to cut less deeply than a coarser, harder material. Also, the softer abrasive may become less effective more quickly as the abrasive is itself abraded. This allows fine abrasives to be used in the polishing of metal and lenses where the series of increasingly fine scratches tends to take on a much more shiny or reflective appearance or greater transparency. A lens is an optical device with perfect or approximate Axial symmetry which transmits and refracts Light, converging or diverging In Optics, transparency (also called pellucidity) is the Material property of allowing Very fine abrasives may be used to coat the strop for a cut-throat razors, however, the purpose of stropping is not to abrade material but to straighten the burr on an edge. Serine/threonine kinase receptor associated protein, also known as STRAP, is a human Gene. A razor is a Bladed Tool primarily used in the Shaving off of unwanted Body hair. The final stage of sharpening Japanese swords called polishing and may be a form of superfinishing. A Japanese sword, or, is one of the traditional bladed weapons of Japan. Superfinishing is a Metalworking Process which produces a very fine Mirror -smooth finish

Different chemical or structural modifications may be made to alter the cutting properties of the abrasive. [6]

Other very important considerations are price and availability. Diamond, for a long time considered the hardest substance in existence, is actually softer than fullerite and even harder aggregated diamond nanorods, both of which have been synthesised in laboratories but no commercial process has yet been developed. "C60" and "C-60" redirect here For other uses see C60 (disambiguation. Aggregated diamond nanorods, or ADNR s (also called "hyperdiamond" are an allotrope of Carbon believed to be the hardest and least Diamond itself is expensive due to scarcity in nature and the cost of synthesising it. Bauxite is a very common ore which, along with corundum's reasonably high hardness, contributes to corundum's status as a common, inexpensive abrasive. An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining

Thought must be given to the desired task about using an appropriately hard abrasive. At one end, using an excessively hard abrasive wastes money by wearing it down when a cheaper, less hard abrasive would suffice. At the other end, if too soft, abrasion does not take place in a timely fashion, effectively wasting the abrasive as well as any accruing costs associated with loss of time.

Other instances of abrasion

Aside from the aforementioned uses of shaping and finishing, abrasives may also be used to prepare surfaces for application of some sort of paint of adhesive. An excessively smooth surface may prevent paint and adhesives from adhering as strongly as an irregular surface could allow. Glue or adhesive is a compound that adheres or bonds two items together Inflatable tyre repair kits (which, on bicycles particularly, are actually patches for the inner tube rather than the tyre) require use of an abrasive so that the self-vulcanising cement will stick strongly. This article is about tires used on road Vehicles including pneumatic tires and solid tires. This article is about tires used on road Vehicles including pneumatic tires and solid tires. Vulcanization (or Vulcanisation refers to a specific curing process of Rubber involving high heat and the addition of Sulfur or other equivalent curatives In the most general sense of the word a cement is a binder a substance which sets and hardens independently and can bind other materials together

Inadvertently, people who use knives on glass or metal cutting boards are abrading their knife blades. A cutting board is a durable board used to place material on to be cut The pressure at the knife edge can easily create microscopic (or even macroscopic) cuts in the board. This cut is a ready source of abrasive material as well as a channel full of this abrasive through which the edge slides. For this reason—without regard for the health benefits—wooden boards are much more desirable. A similar occurrence arises with glass-cutters. See also article Cutting A glass cutter is a Hand tool which aids in the cutting (strictly the controlled breaking of flat Glass-cutters are have circular blades that are designed to roll not slide. They should never retrace an already effected cut.

Undesired abrasion may result from the presence of carbon in internal combustion engines. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 The internal combustion engine is an engine in which the Combustion of Fuel and an Oxidizer (typically air occurs in a confined space called a While smaller particles are readily transported by the lubrication system, larger carbon particles may abrade components with close tolerances. The carbon arises from the excessive heating of engine oil or from incomplete combustion. Motor oil, or engine oil, is an Oil used for lubrication of various Internal combustion engines While the main function is to lubricate Moving Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of This soot may contain fullerenes which are noted for their extreme hardness—and small size and limited quantity which would tend to limit their effect. "C60" and "C-60" redirect here For other uses see C60 (disambiguation.

References

  1. ^ Abrasives engineering glossary. Retrieved on 2007-04-06. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 46 BC - Julius Caesar defeats Caecilius Metellus Scipio and Marcus Porcius Cato in the Battle of Thapsus
  2. ^ Grinding Stresses, Grinding Wheel Institute, 1964
  3. ^ Care of laminate surface. Retrieved on 2007-04-07. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 529 - First draft of Corpus Juris Civilis (a fundamental work in Jurisprudence) is issued by Eastern Roman Emperor
  4. ^ Nutrimetics, Honey and Almond Scrub
  5. ^ OSH Answers: Metalworking fluids. Retrieved on 2007-04-06. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 46 BC - Julius Caesar defeats Caecilius Metellus Scipio and Marcus Porcius Cato in the Battle of Thapsus
  6. ^ FEPA Structure. Retrieved on 2007-04-05. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 456 - St Patrick returns to Ireland as a missionary bishop

See also

Abrasive Machining is a manufacturing process where material is removed from a workpiece using a multitude of small Abrasive particles

Dictionary

abrasive

-adjective

  1. Producing abrasion; rough enough to wear away the outer surface.
  2. Being rough and coarse in manner or disposition.

-noun

  1. A substance or material such as sandpaper, pumice, or emery, used for cleaning, smoothing, or polishing.
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