Saint-Gobain Surface Conditioning's resin bond mesh diamond is a synthetic material with a friable crystal structure for use in vitrified and resin bond systems. The crystals are irregular, elongated and rough-edged, and are suitable for grinding tungsten carbide, ceramics and glasses.
The friability or breakdown of the diamond is a function of its polycrystalline structure and metallic inclusions within the grains. Grains are microfractured during grinding and new edges formed for efficient, free-cutting action.
Resin bond mesh diamond is typically 40µm and larger in particle size and is available in standard electroless nickel (Ni) coatings of 30% and 56% by weight, and a copper (Cu) coating of 50% by weight.
RB (60 / 70 & 70 / 80 & 60 / 80 & 80 / 100)
RB (100 / 120 to 325 / 400)
R-Ni30% (60 / 70 & 70 / 80 & 80 / 100)
R-Ni30% (100 / 120 to 325 / 400)
R-Ni56% (60 / 70 & 70 / 80 & 80 / 100)
R-Ni56% (100 / 120 to 325 / 400)
R-Cu50% (60 / 70 to 70 / 80)
R-Cu50% (80 / 100 to 325 / 400)
A: MESH refers to abrasive particle sizes typically 40 µm (1 µm = 40 microinches) or greater.
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A: A very hard abrasive, usually natural or synthetic diamond and cubic boron nitride (CBN). Hardness is measured on the Knoop Scale in megapascals (1 Mpa = 145 lb / in2 ) and diamond is 7000 Mpa with CBN following at 5000. Conventional abrasives such as silicon carbide and aluminum oxide have much lower Knoop values of 2500 and 2200 respectively.
A: Sieves and screens are used, and in the U.S, the Tyler Equivalent method is popular. The Tyler mesh size is the number of openings per linear inch of mesh. Particle sizes for sieving range from 10 µm to 100,000 µm.
A: Size, shape, color, surface (extrinsic) chemistry, internal (intrinsic) chemistry, mechanical properties -- Ti and TTi (toughness index / impact strength and thermal toughness index), zeta potential (surface charge) and microstructure.
A: Most individual grains of a superabrasive powder batch are not the same size (or shape). The powder consists of a distribution of particles of different sizes represented as a frequency distribution curve.
A: Electroless nickel plating (EN) is an auto-catalytic chemical technique used to deposit a layer of nickel-phosphorus on a solid workpiece, such as metal or plastic. The process relies on the presence of a reducing agent, for example hydrated sodium hypophosphite (NaPO2H2·H2O) which reacts with the metal ions to deposit metal. Alloys with different percentages of phosphorus, ranging from 2 - 5 (low phosphorus) to up to 11 - 14 (high phosphorus) are possible. The metallurgical properties of alloys depend on the percentage of phosphorus.
A: Essentially the same process as electroless nickel, but copper is the coating element.
A: To improve the adhesion of the superabrasive in the bond matrix of the grinding wheel and to aid removal of heat from the grinding zone.
A: Ti and TTi stand for Toughness Index and Thermal Toughness Index. This is a measurement of the impact strength of the superabrasive and its ability to resist mechanical breakdown (friability).
The Ti test is performed on a superabrasive at room temperature. The TTi test is run at room temperature on a superabrasive previously raised to an elevated temperature and allowed to cool down – this mimics the performance of the superabrasive in a grinding wheel in “real world” conditions.
The Ti and TTi test is performed to ANSI (American National Standards Institute).
A: A measure of the ability of a superabrasive to be pulverized, crumbled or otherwise reduced to a powder. Ti and TTi testing are employed to measure friability in superabrasives.
A: Diamond is an allotrope of carbon, where the atoms are arranged in a variation of the face-centered cubic crystal structure called an atomic diamond lattice. It is this atomic structure which defines diamond's hardness. Diamond is well-known as a material with excellent physical qualities, most of which depend on strong covalent bonds between its atoms. Diamond has the highest hardness and thermal conductivity of any material and those properties make it the abrasive of choice in many industrial drilling, grinding, lapping and polishing applications.
The basic physical and chemical properties of synthetic diamond and CBN types can influence the performance of grinding wheels and superabrasive tools. Several properties should be considered when choosing the optimum superabrasive for a specific application: