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Machining. It is a metal removing operation from the work piece with the help of machine tools and cutting tools. Metal is removed in the form of chip from the workpiece. Names of commonly used machine tools:. Lathe machines, Drilling machines, Grinders,
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Machining • It is a metal removing operation from the work piece with the help of machine tools and cutting tools. Metal is removed in the form of chip from theworkpiece.
Names of commonly used machine tools: Lathemachines, Drillingmachines, Grinders, Shapingmachines, PlanningMachines, MillingMachines Boring Machines Metal CuttingSaws Slotting machinesetc.
Basic principle of a lathe machine: • Lathe machines are normally usedtoproduce heldinthechuck cylindricalsurfaces.Thejobis attached to the head stock or between the centers provided at the head stock or tail stock. The tool is held on the compound rest. Job is rotated at the predetermined speed by the head stock. The tool is moved relative to the workpiece with the help of carriage, cross slide or compound rest. Desired quantity of metal is removed in the form of chip from the workpiece.
Specification of a lathemachine • Alathemachineisspecifiedbythefollowing • Height of the centers measured from the lathebed. • Swingdiameteroverbed.Thisthelargestdiameterofwork piece which will revolve without touching the bed. It is equaltwicetheheightofcentersfromthebed. • Swingdiameterovercarriage.Itisthelargestdiameterthat can revolve over the cross-slide. This always less than the swing diameter over thebed. • Maximumbardiameter.Thisisthemaximumdiameter thatwillpassthroughtheheadstockspindle. • Length of thebed.
Classification of Lathemachines • Lathescanbeclassified intofollowingthreetypes • EngineLathes • Light weight bench enginelathe • Precision Tool Roomlathes • Gaplathes • TurretLathes • Special Purposelathes
Basic OperationsPerformedon a Lathe Machine: Turning –Plain turning , Stepturning Facing TaperTurning Drilling: Boring: Reaming: Knurling: Forming: Chamfering: Parting Off: Threading or threadcutting
ShapingMachines • A shaper is used for producing relatively small flat surfaces. A single point tool is mounted on a tool box fitted to a reciprocating ram. The job is clamped in a vice. There is a cutting action in the forward motion of the tool while the return stroke is idle. Job is given indexedfeed.
Shaperoperations • Horizontalcutting • Verticalcutting • Inclinedcutting • Irregularcutting
PLANNING MACHINE ORPLANNER • Planning machines are used for generating large flat surfaces.These flat surfaces may be horizontal, vertical or inclined. Planing machines also perform all the functions that a shaping machine does. The planning machines handle larger and heavyjobs. • In planning machines the job is mounted on a table which moves forward and backward. The tool is held firmlyonthecrossrailsinthemiddleofthemachine.
Diff. between shaper and planer Planing Machine ShapingMachine 1. Machine is heavy and isusedfor 1.Machineislightandonlysmalljob producing largesurfaces can beproduced. 2. Cutting takes place by 2. Cutting takesplaceby reciprocating the workpiece 3. Heavier cuts can begiven reciprocating thetool. 3.Onlylightcutscanbegiven. 4. Several tools can bemountedand 4.Onlyonetoolisusedatatime. employed at atime 5. Only one job can be taken up at a similar time. 5.Severaljobsrequiring operations can be machined time ata6.Indexedfeedisgiventothejob during idle stroke of theram. 6. Indexed feed is given to the tool during idle stroke of the worktable.