AbrasivesandBondedAbrasivesAbrasiveGrainSizeAbrasives are very small when compared to the size ofcutting tools and insertsAbrasives have sharpedges and allow removal ofsmall quantities of materialVery fine surface finish and dimensional accuracy canbe obtained using abrasives as toolsSize of an abrasive grain is identified by a grit numberSmaller the grain size, larger the grit number
Abrasives and Bonded Abrasives Abrasive Grain Size Abrasives are very small when compared to the size of cutting tools and inserts Abrasives have sharp edges and allow removal of small quantities of material Very fine surface finish and dimensional accuracy can be obtained using abrasives as tools Size of an abrasive grain is identified by a grit number Smaller the grain size, larger the grit number
AbrasivesandBonded Abrasives:GrindingWheelsEach abrasive grain removes only a very small amountof material at a timeHigh rates of material removal can be achieved whenlarge number of these grains act togetherDonebyusingbonded abrasivesBondGrindingPorositywheelGrainBond fractureMicrocracksGrainfractureWorkpieceAttritious wearWheelsurtace
Abrasives and Bonded Abrasives: Grinding Wheels Each abrasive grain removes only a very small amount of material at a time High rates of material removal can be achieved when large number of these grains act together Done by using bonded abrasives
AbrasivesandBonded Abrasives:BondTypesCommon types of bonds:1.Vitrified:Consistoffeldsparand claysStrong, stiff,porous, and resistant to oils acids, andwater2. Resinoid:Bonding materials are thermosetting resinsResinoid wheels are more flexible than vitrifiedwheels
Abrasives and Bonded Abrasives: Bond Types Common types of bonds: 1. Vitrified: Consist of feldspar and clays Strong, stiff, porous, and resistant to oils acids, and water 2. Resinoid: Bonding materials are thermosetting resins Resinoid wheels are more flexible than vitrified wheels
AbrasivesandBonded Abrasives:BondTypes3.Reinforced Wheels:Consist of layers of fiberglass mats of various meshsizes4.Thermoplastic:Used in grinding wheelsWith sol-gel abrasives bonded with thermoplastics5.Rubber:Using powder-metallurgytechniquesLower in cost and areusedfor small productionquantities
Abrasives and Bonded Abrasives: Bond Types 3. Reinforced Wheels: Consist of layers of fiberglass mats of various mesh sizes 4. Thermoplastic: Used in grinding wheels With sol-gel abrasives bonded with thermoplastics 5. Rubber: Using powder-metallurgy techniques Lower in cost and are used for small production quantities
TheGrindingProcessGrinding is a chip-removal process that uses anindividual abrasive grain as the cutting toolGrainVChipWearflatAbrasivegrainChipoWorkpieceWorkpiece10μm
The Grinding Process Grinding is a chip-removal process that uses an individual abrasive grain as the cutting tool