IMS ENGINEERING COLLEGE ,GHAZIABAD (U IMS ENGINEERING COLLEGE ,GHAZIABAD (U.P) Department of Mechanical Engineering TOPIC:-EDM,ECM & LBM Submitted by :- Keshav gupta Roll no. :-1214340078 Batch :-ME-1 (2012-2016)

CONTENTS EDM, ECM & LBM Introduction Working principle Advantage Disadvantage Application

NEED FOR UNCOVENTIONAL MACHINING Hardness & strength of material is very high. Workpiece is too flexible ,difficult to clamp in workholding device. Shape of the part is complex. Surface finish & dimentional accuracy is better.

ELECTRIC DISCHARGE MACHINING Electric discharge machining (EDM) a is non convectional machining technique in which material is removed by the erosive action of electric discharge (sparks) provided by a generator It is primarily used for hard metal or those that would be impossible to machine with traditional techniques. EDM can cut a small or odd –shaped angle ,cavity in extremely hard steel and exotic metals such as titanium , hastelloy , kovar ,inconel and carbide. EDM is a method of removing material by a series of rapidly recurring electric discharges b/w an electrode (cutting tool) and the work piece, in presence of an energetic electric field.

Electrical discharge machine working principle The workpiece , made of electrically conductive material , is connected to one pole of pulsed power supply. The electrode is connected to the remaining pole of power supply.A small gap is maintained b/w the two. An insulating (dielectric) fluid is flooded b/w the electrode and the workpiece. its function is to provided a controlled amount of electrical resistance in the gap. When pulse of dc electricity is delivered to the electrode and the workpiece , an intense electrical field is created at the point where surface irregularities provide the narrowest gap. As a result of this field , naturally occurring microscopic contaminants suspended in the dielectric fluid begin to migrate and concentrate at the strongest point in this field

ADVANTAGE Complex shapes that would otherwise be difficult to produce with conventional cutting tools. Extremely hard material to very close tolerances. Very small work pieces where conventional cutting tools may damage the part from excess cutting tool pressure. There is no direct contact between tool and work piece. Therefore delicate sections and weak materials can be machined without any distortion. A good surface finish can be obtained. very fine holes can be drilled.

DISADVANTAGE The slow rate of material removal. Potential fire hazard associated with use of combustible oil based dielectrics. The additional time and cost used for creating electrodes for ram/sinker EDM. Reproducing sharp corners on the workpiece is difficult due to electrode wear. Specific power consumption is very high. Power consumption is high. "Overcut" is formed. Excessive tool wear occurs during machining.

APPLICATION Prototype production Closed loop manufacturing Small hole drilling Metal disintegration machining Coinage die making

Electrochemical machining Electrochemical machining (ECM) is a method of removing metal by an electrochemical process. It is normally used for mass production and is used for working extremely hard materials or materials that are difficult to machine using conventional methods.  Its use is limited to electrically conductive materials. ECM can cut small or odd-shaped angles, cavities in hard and exotic metals, such as titanium aluminides, Inconel, Waspaloy, and high nickel, cobalt, and rhenium alloys. Both external and internal geometries can be machined. In ECM, no sparks are created.

Electrochemical machine working principle An electrode and workpiece (conductor) are placed in an electrolyte ,and a potential voltage is applied. On the anode side the metal molecules ionize (lose electrons) break free of the workpiece, and travel through the electrolyte to the electrode. Variation in the current density will result in work taking the electrode shape. The electrode is fed with a constant velocity ,and electrolyte is fed through the tool Tool is designed to eliminate deposition of the ionized metal on the electrode. The

Advantages Because the tool does not contact the workpiece, there is no need to use expensive alloys or tempering procedures to make the tool tougher than the workpiece. As a result, the tools can be made from any cheap and easily machined, cast, or engraved electrically conductive substance. There is less tool wear in ECM, and less heat and no stress are produced in processing that could damage the part. Fewer passes are typically needed, and the tool can be repeatedly used

Disadvantages The saline (or acidic) electrolyte poses the risk of corrosion to tool, workpiece and equipment. Only electrically conductive materials can be machined.

APPLICATIONS Some of the very basic applications of ECM include: Die-sinking operations Drilling jet engine turbine blades Multiple hole drilling Machining steam turbine blades within close limits jet engines

Similarities b/w EDM&ECM The tool and workpiece are separated by a very small gap, i.e. no contact in between them is made. The tool and material must both be conductors of electricity. Needs high capital investment. Systems consume lots of power. A fluid is used as a medium between the tool and the work piece (conductive for ECM and dielectric for EDM). The tool is fed continuously towards the workpiece to maintain a constant gap between them (EDM may incorporate intermittent or cyclic, typically partial, tool withdrawal).

Laser beam machining Laser beam machining (LBM) is an unconventional machining process in which a laser is directed towards the work piece for machining. Since the rays of a laser beam are monochromatic and parallel it can be focused to a very small diameter and can produce energy as high as 100 MW of energy for a square millimeter of area. It is especially suited to making accurately placed holes. It can be used to perform precision micro-machining on all microelectronic substrates such as ceramic, silicon, diamond, and graphite. Examples of microelectronic micro-machining include cutting, scribing & drilling all substrates, trimming any hybrid resistors, patterning displays of glass or plastic and trace cutting on semiconductor wafers and chips. A pulsed ruby laser is normally used for developing a high power.

Laser beam machine working application Laser cutting is a technology that uses a laser to cut materials, and is typically used for industrial manufacturing applications, but is also starting to be used by schools, small businesses, and hobbyists. Laser cutting works by directing the output of a high-power laser most commonly through optics. The laser optics and CNC (computer numerical control) are used to direct the material or the laser beam generated. A typical commercial laser for cutting materials would involve a motion control system to follow a CNC or G-code of the pattern to be cut onto the material. The focused laser beam directed at the material, which then either melts, burns, vaporizes away, or is blown away by a jet of gas,leaving an edge with a high-quality surface finish. Industrial laser cutters are used to cut flat-sheet material as well as structural and piping materials.

CNC Machine Language G-Code List G-Code is one of a number of computer code languages that are used to instruct CNC machining devices what motions they need to perform such as work coordinates, canned cycles, and multiple repetitive cycles. Industry has standardized on G-Code as its basic set of CNC machine codes

Laser beam machine working principle The tool (electrode) usually acts as a cathode and is immersed in a dielectric fluid. DC voltage (~300V) is applied in modulated pulses(200-500K Hz). The dielectric breaks down (sparking at around 12,000 deg F) when gap is small. The sparks erodes the workpiece in the shape of the tool. The tool is progressively lowered as the workpiece erodes. Material removal rate is typically 300 mm3/min Tool wear ratio 3:1 with metallic electrodes, 3:1-100:1 with graphite electrodes

WIRE EDM

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