Presentation on theme: "PROPERTIES AND SELECTION OF MATERIALS"— Presentation transcript:
1 PROPERTIES AND SELECTION OF MATERIALS “ELECTRO MACHINING”Presented by:MUDIT RAJ YADAV 2008AMD3110DEPTT. OF APPLIED MECHANICSIIT DELHIPresented to:PROF. M.P. GURURAJANDEPTT. OF APPLIED MECHANICSIIT DELHI
2 ELECTRO DISCHARGE MACHINING(EDM) ELECTRO MACHININGELECTRO DISCHARGE MACHINING(EDM)ELECTRO CHEMICAL MACHINING(ECM)
3 ELECTRO DISCHARGE MACHINING (EDM ) ELECTRO CHEMICAL MACHINING (ECM)Electrical energy is use to cut material to final shape. (SPARK EROSION PROCESS).When a difference of potential is applied between two conductors immersed in a dielectric fluid. Fluid will ionize, if the potential diff. reaches a high enough value and a spark will occur.If both the electrodes are of same material then +ve one (anode, work piece) will have more erosion.A gap of 0.01 to 0.05 mm is maintained, it governs the MRRCurrent vary from 0.5 to 400 ampVoltage V DCFluid is pumped with a pressure of 2 kg/cm2.Electrical energy is use to cut material to final shape (No spark)In this process an electrolytic cell is formed by the anode (work piece) and cathode (tool) in the midst of a flowing electrolyte.Due to electrolytic process at the cathode, -ve ions are released which combine with the metal ion of anode to form insoluble metal hydroxides.Thus the metal is mainly removed in the form of slugs and precipitatesThis process is reverse of electro plating but the metal is pumped in the flowing electrolyte before it gets stuck on the tool surfaceGap mmvoltage D.C. supply(5-30 volts)current of order ampFluid pressure =14 kg/cm2
7 FEATURES OF EDM Used for:- Super alloys Ti Steels Fluids:- Paraffin withWhite spirit orTransformer oilTool materials:-GraphideCuCu-WcApplications:-Dies, punchAircraft industry-fuel injector, nozzlesTo make holes in turbine bladesChange in properties:-Residual stressesPlastic deformation may occurFine cracks in machined area
10 FEATURES OF ECM Applications:- Profiled cavity Carbide tools Used for:-(>400BHN)Ni alloysTi alloysWC alloysFluids:-Natural saltsAcidsAlkalisTool materials:-BrassCuSteelsApplications:-Profiled cavityCarbide toolsDies, punchFuel injector, nozzlesTo make holes in turbine bladesChange in properties:- (No spark)So no metallurgical change (temp about C)No change in properties likeMelting pointCompositionHardness, toughness, brittleness etc
11 CONCLUSIONSBoth used electrical energy as source.Both processes are highly précised and modern techniques of machining.Both are used for machining of hard materials(>2000BHN ).Change in properties are negligible or none.But can be used for electric conductor materials only.Both can produces complex shape.