Milling machines

Milling MachinesBy

Avinash N. Fulbaria

ContentIntroductionMilling ParametersTypes of Milling MachineMilling OperationsMilling CuttersComponents Of Milling MachineReference

Milling Or Milling MachineMilling: a

process in which a rotating multi-tooth cutter removes material while traveling along various axes with respect to the work piece.

Cutter

Workpiece

Milling Parameters Cutting speed : it is the peripheral

speed of the milling cutter relative to the work.

V= πdN m per minute 1000 where V= cutting speed d = Diameter of cutter in mm N = RPM of cutter

Milling ParametersFeed : It is ratio of linear speed of

workpiece to the product of number of teeth and rpm of cutter.

F = V NnWhere , V = linear speed of

workpiece n = number of teeth

Milling ParameterMilling Time : t = l + la V l = Length of workpiece la = approach length

Milling ParameterMetal Removal Rate MRR = lwb tWhere w = width of the cut

Types of Milling MachineConventional milling machineBed type milling machine Column- knee type milling

machine CNC milling machine (VMC)

Column and Knee Type Milling m/c

Bed Type Milling m/c

CNC Milling m/c

Milling OperationsPeripheral milling Face millingEnd milling

Peripheral MillingIn peripheral

milling (also called plain milling), the axis of cutter rotation is parallel to the work piece surface.

Up milling Down milling

Face Milling The cutter is

mounted on a spindle whose axis of rotation is perpendicular to workpiece surface.

Tool

Workpiece

Milling CuttersStraddle: More cutters are used to machine two

parallel surfaces on the workpiece.

Form milling : It produces curved profiles using cutters that have specially shaped teeth.

Slotting and slitting operations are performed with circular cutters. Eg.T-slot cutters

Slotter Cutter

Components Of Milling MachineWorktable: on which the work piece is clamped

using T-slots. The table moves longitudinally relative to the saddle.

Saddle: supports the table and can move in the transverse direction.

Knee: supports the saddle and gives the table vertical movement so that the depth of cut can be adjusted and work pieces with various heights can be accommodated.

Overarm: used on horizontal machines; it is adjustable to accommodate different arbor lengths.

Head: contains the spindle and cutter holders.

ReferenceS.K. Hajra Choudhary , A.K. Hajra

Choudhary , Nirjhar Roy , Elements of Workshop Technology , Vol 2 (12th Edition), Media Promoters & Publishers PVT. LTD

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