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Non Conventional Methods of Machining |
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Electric-Discharge Machining (EDM): It is especially suited for cutting intricate contours or delicate cavities.
It is also called Spark Machining because it removes metal by producing a rapid series of repetitive electrical
discharges. These electrical discharges are passed between an electrode and the piece of metal being machined.
The small amount of material is flushed away which is removed from the workpiece with a continuously flowing fluid.
The repetitive discharges create a set of successively deeper craters in the work piece until the final shape
is produced. It is most widely used by the mold-making tool and industries. It is increasingly applied to make
prototype and production parts especially in the aerospace and electronics industries.
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Electric-Discharge Grinding (EDG) : It is a process which works on the same principle as Electric-Discharge
Machining except that the electrode is in the form of a grinding wheel.
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Electro-Chemical Machining (ECM) : This process uses electrolytes which dissolve the reaction products formed
on the workpiece by electrical action. It has been successfully put to work in the areas like electroplating,
electroforming, and electropolishing. The electrical energy is used to produce a chemical reaction therefore the
machining process is called Electro-Chemical Machining. It is also known as Contactless Electrochemical Forming Process.
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Chemical Machining (CHM) : This process removes the metal by the chemical attack of corrosive liquid.
The areas of the workpiece which are not to be machined are masked. The workpiece is then either immersed in or exposed to a
spray of chemical reagent. This machining process is also known as Chemical Milling because in its earliest use it replaced
milling.
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Ultrasonic Machining (USM) : This process removes material using an abrasive slurry driven by a special tool
vibrating at a high frequency along a longitudinal axis. It is used commonly to produce blind holes, through holes, slots
and irregular shapes. This process is able to machine any material but it is more efficient on brittle materials.
It can be also called as Ultrasonic Impact Grinding.
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Abrasive Jet Machining (AJM) : In this process the material is removed by the erosive action of high-velocity abrasive
particles impinging on the work surface. The abrasive particles are accelerated and carried by a compressed-air stream
issuing out of a nozzle. Generally alumina (Al2O3) powder or silicon carbide (SiC) powder is used as
the abrasive.
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Laser Beam Machining (LBM) : The basic principle of this process is the conversion of electrical energy into
coherent light. This process uses lasers for performing operations which are traditionally performed with cutting
tools. Those operations include cutting, drilling, slotting and scribbling. The coherent light or laser beam is
focused on the workpiece where it is converted into thermal energy which melts the material.
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Electron Beam Machining (EBM) : In this process the material is removed by focusing high velocity electrons on the
workpiece. Unlike lasers, it is carried out in a vacuum chamber. It is used for drilling small holes in all type of
materials including ceramics.
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