Lathe

INTRODUCTION

A machine which performs the material removal operation with tools, to produce desired shape and size of the workpiece, is known as a machine tool.

INTRODUCTION

In some cases of machining, motion is given to the work piece and tool remains stationary.

In some other cases, the work piece is stationary and the machine tool provides motion to the cutting tool.

In yet other cases, motion is given both to tool as well as the work piece

INTRODUCTION

The relative motion between the tool and work piece results in a thin strip of material being sheared off from the work piece reducing the thickness of the work piece.

INTRODUCTION

The various types of machine tools commonly used in workshops are:

- Lathe machine.- Shaper machine.- Planer machine.- Drilling machine.- Grinding machine.- milling machine.

TYPES OF LATHE

Speed latheCentre latheBench latheTool room latheCapstan and turret latheAutomatic lathe

PRINCIPLE PARTS OF LATHE

PRINCIPLE PARTS OF LATHE Machine bed, usually made of cast iron. It holds or

supports all other parts of the lathe. The top of the machine bed is flat and is machined to form guide ways on which the carriage slides along the length of the lathe.

Headstock: It is fixed at the extreme left hand of the bed and contains shafts and gears immersed in lubricating oil. The driving shaft inside is driven by an electric motor. The driven shaft, which is in the form of a hollow spindle can be driven at various r.p.m. by changing gears, projects out of the headstock, A chuck (either three jaws or four jaws), is screwed on this spindle.

PRINCIPLE PARTS OF LATHE Tailstock: A tailstock is provided at the right hand end

of the bed. It can slide along the guide ways provided on the bed The tailstock has a spindle in the upper part of the tailstock, the axis of which coincides with the axis of the headstock spindle, both being at the same height above the bed

PRINCIPLE PARTS OF LATHE

The carriage controls and supports the cutting tool. It moves on the ways of the bed, its motion is parallel to rotational axis of the spindle.

FEED MECHANISM

Longitudinal feed mechanism: when the tool moves parallel to the work.Cross feed mechanism: when the tool moves perpendicular to the work.Angular feed mechanism : when the tool moves at the angle to the work

SIZE AND SPECIFICATION OF A LATHE

LATHE TOOLS

The material used for lath tools should have:

- Hardness.- Toughness.- Heat resistance.- Low wear.

OPERATIONS ARE CARRIED OUT ON LATHES

(i) Turning (ii) Facing (iii) Taper turning (iv) Profile turning or form turning (v) Parting (vi) Boring (vii) Threading (viii) Knurling.

DIFFERENT OPERATIONS ON LATH MACHINE

THE TOOLS USED FOR THESE OPERATIONS

BASIC PROCESS

TURNING

Fig-2 Basic scheme of Turning

CUTTING FORCES COMPONENTS

TERMS USED IN LATHE MACHINING1- Cutting Speed :The speed at which the metal is removed by the tool from the workpiece(it is the peripheral speed of the work past the cutting tool It is usually expressed in metres per minutes. 2- Feed : the distance which the tool advances for each revolution of the work. It is usually expressed in mm.3- Depth of cut : It is defined as the depth of penetration of the tool into the workpiece during machining

CUTTING SPEED

TABLE WITH PARAMETERS OF: CUTTING SPEED, FEED, DEPTH OF CUT

SHAPERS AND PLANERS

Both shapers and planers are machine tools which produce a flat surface. They are capable of machining a horizontal, vertical or inclined flat surface.

SHAPERS

CUTTING TOOLS USED IN SHAPING

VARIOUS OPERATIONS PERFORMED ON A SHAPING MACHINE

PLANER OR PLANNING MACHINEPlaner is used to machine flat surfaces on work pieces, which are too large and heavy to be accommodated on a shaping machine table.

The fundamental difference between a planer and shaper is that in a planer, the cutting tool remains stationary and the planer table on which the work piece has been clamped moves past the cutting tool

PLANER OR PLANNING MACHINE

DIVERSE TYPE OF MACHINING OPERATIONS PERFORMED ON A PLANER