MANUFACTURING PROCESSES

AMIRAJ COLLEGE OF ENGINEERING & TECHNOLOGY.Singh Abhishek RavinderSemister-3rdMechanical Dept.

Classification of Milling Machines2

MILLING Milling is another basic machining process by which surface is generated progressively by the removal of chips from a work piece as it is fed against a rotating cutter.

Milling operations can be classified into two broad categories1. Peripheral Milling2. Face Milling

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Peripheral Milling 4

Peripheral MillingOperation performed by milling cutter to produce a machined surface parallel to axis of rotation of cutter

Cutting force is not uniform throughout the length of the cut by each tooth

Quality of surface generated and shape of the chip formed depends upon the rotation of cutter relative to direction of feed movement

It can be either UP milling or DOWN milling

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Up millingAlso called conventional milling,- Wheel rotation opposite of the feed- The chip formed by each cutter tooth starts out very thin and increases its thickness- The length of the chip is relatively longer- Tool life is relatively shorter- Need more clamping force to hold the work part still.

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Down milling:

Also called climb milling,- Wheel rotation is parallel to the feed- The chip formed by each cutter tooth starts out thick and leaves out thin- The length of the chip is relatively short- Tool life is relatively longer- Need less clamping force to hold the work part still.7

Face Milling

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Face MillingThe generated surface is at right angles to the cutter axis

It is the combined result of actions of the portions of the teeth located on both periphery and the face of the cutter

Most of the cutting is done by the peripheral portions of the teeth, with the face portions provides the surface finish.

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MILLING MACHINES10

Milling MachinesThe milling machine supplies an accurate rotating spindle for the cutter and a table (vise) to fix and position the work part.

Types of Milling Machines are -:

Column & Knee Type Fixed Bed Type Planer Type Special Type

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Column & Knee Milling Machine12

General purpose

Column, spindle, cutter, table, knee, base are the common parts of the vertical and horizontal milling machines

The milling machines having only the three mutually perpendicular table motions (x-y-z axes) are called plain column and knee type

Vertical type is especially well suited for face and end milling operations

Horizontal Milling Machine13

In horizontal, arbor supports the cutter and an over arm supports arbor

The vertical column houses the electrical, main drive, spindles etc mounted on a heavy base

14Universal Milling Machine Has a table that can be rotated in a horizontal plane to any specified angle

Bed Type Milling Machine15

Milling Operations

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1. Plain Milling(Slab Milling)

Operation of production of plane flat surface parallel to axis of rotation of plain milling cutter

Cutter width extends beyond the work piece on both sides

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2. Face Milling

The face milling cutter is rotated about an axis perpendicular to the work surface

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19More Examples on Face Milling

3. End Milling

Combination of peripheral and face millingCutter has teeth both on end face and peripheryVertical milling machine is most suitable for end milling operation

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4. Side Milling

Operation of production of flat vertical surface on side of work piece by using side milling cutter

Depth of cut adjusted by rotating vertical feed screw of the table21

5. Straddle Milling

Operation of production of flat vertical surfaces on both side of the workpiece by using two side milling cutters mounted on the same arbor22

6. Angular MillingOperation of production of angular surface on a workpiece other than at right angles to the axis of milling machine spindle

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7. Gang Milling

Operation of milling several surfaces of the workpiece simultaneously by feeding the table against a number of cutters having same or different diameters

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8. Form Milling

It is the operation of production of irregular contours using form cuttersThe contours maybe convex, concave or any other shape

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9. Profile Milling

It is the operation of reproduction of an outline of a template or complex shape of a master die on a workpiece

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10.Milling Keyways, Grooves & Slots

Operation of production of keys, grooves and slots of varying shapes and size by using a plane milling cutter, a metal slitting saw, an end mill or by side milling cutter27

11. Thread Milling

Operation of production of threads by using a single or multiple thread milling cutter.It is performed in special thread milling machine to produce accurate threads

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