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MAYURBHANJ SCHOOL OF ENGINEERING

BRANCH – Mechanical engineering

SUBJECT – Manufacturing Technology

SEMESTER – 4^TH

TOPIC – Internal machining process( Drilling )

NAME OF THE TEACHER – ER. ASHOK KUMAR PATRA

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CONTENTS

INTRODUCTION

A drill is a rotary end-cutting tool with one or more cutting lips and usually one or more flutes for the passage of chips and the admission of cutting fluid. A drilling machine is a machine tool designed for drilling holes in metals. It is one of the most important and versatile machine tools in a workshop.

WORKING PRINCIPLE OF DRILLING MACHINE

Working Principle of Drilling Machine: When the power is given to the motor, the spindle rotates and thereby the stepped pulley attached to it also rotates. On the other end, one more stepped pulley is attached and that is inverted to increase or decrease the speed of the rotational motion.

PARTS OF DRILLING MACHINE

TYPE OP DRILLING MACHINES

A drilling machine is used to form a hole of different sizes on a job, drilling is a metal removing process, by a drilling machine you can do drilling operation, reaming operation and boring operation.

OPERATION OF DRILLING MACHINE

The column or pillar is situated on one side of the base. In general, we use a radial column so that the movement of the arm is possible in a clockwise or anti-clockwise direction.
The column is also made of cast iron or steel and is also very rigid so that it can carry the load of the arm as well as a drill head.
A sliding table is mounted on the column so that the table can have up and down motion according to the need.

One side of the arm a drill head is mounted, a drill head is consist of various feed and driving mechanism.
A drill chuck is mounted over it. A drill head can slide up and down as per the requirement of the job.
A V-types belt is provided to transfer the power from the motor to the pulley and from pulley, the mechanical power is transferred to the drill head.
The different types of speed can be generated by the cone pully mechanism as well as a gear-train mechanism.

In a drill machine, we use an electric motor, V-belt, and pulley to transfer the power from the motor to the spindle.
For the up and down motion of the drill head, we use hand and as well as automatic feed by an electrical motor. Here also a rack and pinion are used to convert the rotational movement from electrical motor or by hand to the straight-line movement.
Spindle:
It is a circular taper shaft which helps to hold the drill chuck. It is made of high carbon chromium steel or stainless steel or steel alloys.
It transfers the rotary motion from drill head to drill jig

The chuck is mounted on the lower end of the spindle, it holds the drill jig. Here also a keyhole is provided to change the drill jigs.
Drill chucks are generally self-centering. In a drill machine, we use three-jaw chuck. And it is made of special alloy steel.