Metal machining and orthogonal cutting model

5/22/2011

Machining Processes

Chapter I Theory of Metal Machining
◦ Overview of machining Technology ◦ Theory of chip formation in metal machining
 The orthogonal cutting model  Actual chipformation

◦ Force relationships and the Merchant Equation
 Forces in metal cutting  The Merchant Equation

◦ Power and Energy relationships in machining ◦ Cutting Temperature
 Analyticalmethods to compute cutting temperatures  Measurement of cutting temperature

Before beginning
Conventional Machining

Turning and related operations Drilling and related operations Milling Othermachining processes

Material Removal Processes

Abrasive Processes

Grinding Other abrasive processes

Electro- discharge machining Nontraditional machining and thermal cutting processesElectrochemical machining Thermal energy processes Chemical machining

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Some basic definitions…
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Material removal processes
A family of shaping operations in which excess materialis removed from a starting workpart so that what remains is the desired final geometry.

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Conventional machining processes
Processes in which a sharp cutting tool is used to mechanically cutthe material to achieve the desired geometry.

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Abrasive processes
Processes in which material is mechanically removed by the action of hard, abrasive particles

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Nontraditional processesProcesses that used various energy forms other than sharp cutting tool or abrasive particles to remove material

Machining
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A manufacturing process in which a sharp cutting tool is used to cutaway material to leave the desire part shape.

The predominant cutting action in machining involves shear deformation of the work material to form a chip; as the chip is removed, a new surface isexposed.

Advantages and Disadvanges
Why is it so important?
•Variety of work materials •Variety of part shapes and geometric features •Dimensional accuracy •Good surface finishes

•Wasteful of...