Explain the working principle of Lathe, Drilling and Milling machine.

Working Principle of Lathe, Drilling, and Milling Machines

1. Lathe Machine Tool

Purpose: Used for producing cylindrical objects and performing metal cutting operations like turning, facing, threading, etc.

Working Principle:

A lathe machine works on the principle of a rotating workpiece and a stationary cutting tool.

• The workpiece is held and rotated about its axis.
• The cutting tool is fed in a linear direction, removing material in the form of chips.
• This results in shaping the material into the desired size and form.

Main Parts:

• Bed: Base of the machine.
• Headstock: Houses the motor and spindle to rotate the work.
• Tailstock: Supports the other end of the work or holds tools like drills.
• Carriage: Holds and moves the cutting tool.
• Feed Mechanism: Moves the tool automatically or manually.

Common Operations:

• Turning
• Facing
• Knurling
• Drilling
• Thread cutting
• Boring

2. Drilling Machine Tool

Purpose: To drill cylindrical holes in metal workpieces with precision and ease.

Working Principle:

A drilling machine works on the principle of rotating a drill bit to cut a hole in a stationary workpiece.

• The rotating drill bit is fed into the material.
• As the bit rotates and applies axial pressure, it cuts and removes material to create holes.

Main Parts:

• Base: Supports the machine.
• Column: Supports table and drill head.
• Table: Holds the workpiece.
• Drill Head: Contains the motor, spindle, and feed mechanism.

Common Operations:

• Drilling
• Reaming
• Boring
• Tapping
• Countersinking
• Spot facing

3. Milling Machine Tool

Purpose: To perform operations like cutting, slotting, gear shaping, keyways, and complex profiles.

Working Principle:

A milling machine works on the principle of a rotating multi-point cutter removing material from a stationary workpiece.

• The workpiece is fed against a rotating cutter.
• Material is removed in the form of small chips from the surface of the workpiece.

Types of Milling Operations:

• Up Milling (Conventional Milling): Work is fed opposite to the direction of cutter rotation.
• Down Milling (Climb Milling): Work is fed in the same direction as the cutter.

Main Parts:

• Base: Foundation of the machine.
• Column: Supports the spindle and overarm.
• Knee: Vertical support that can move up and down.
• Saddle: Mounted on the knee for crosswise movement.
• Table: Holds the workpiece.
• Arbor: Holds the rotating cutter.
• Overhanging Arm: Supports the free end of the arbor.

Common Operations:

• Face milling
• Side milling
• Slotting
• Gear cutting
• Profile milling

Comparison: