Lendi Institute of Engg &Technology

Boring machineBy

Polaiah(asst prof)

Introduction

When internal surface of a hollow part is turned, a single point cutting tool is used for enlarging a hole, the operation is called BORING

The bar on which single point tool is mounted is called BORING BAR

Types of Boring Machines Horizontal Boring Machine ( HBM )1. Table type HBM2. Planer type HBM3. Floor Type HBM4. Multiple Spindle HBM Vertical Boring Machine ( VBM ) 1. Single Column VBM2. Double Column VBM

Types

Horizontal boring machine:

The work is supported on a table which is stationary and tool revolves in a

horizontal axis.

Can perform boring, reaming, turning, threading, facing, milling , grooving

and many other operations with suitable tools.

Work piece which are heavier and asymmetrical can be easily held and

machined.

Different types has been designed to suit the different purpose.

Horizontal boring machine

Horizontal boring machine

Horizontal Line Boring Machine

Vertical Boring Machine:

The work rotates on a horizontal table about a vertical axis and the tool

is stationary except for feed.

Machine may look like a vertical lathe.

Larger diameter and heavy work pieces, can be set up more quickly than

in lathe.

Multiple tooling may be adapted with its turret type tool post, increasing

the rate of production.

Vertical boring machine

Vertical boring machine

Vertical Boring Operations

Vertical Boring Operations

JIG BORING MACHINE

Jig Boring Machine It uses a single point cutting tools to machine surfaces rapidly and

accurately.

Cemented carbide and diamond tipped tools are operated at a very high

cutting speed to produce accurately sized holes with fine surface.

Jig boring machine is a precision boring machine, resembles to vertical

milling machine in construction.

Accurate positioning of holes is achieved by Lead screw method or

Mechanical / Electrical Gauging method or Optical measuring method.

Jig Boring Machine

Jig-Boring Machine  a metal-cutting machine for finishing holes, planes, and

slots with a highly precise location of centers or surfaces without the use of

special attachments for tool alignment.

Jig-boring machines are used for boring, drilling, counter-sinking, reaming,

milling, and other types of finishing in individual and small-scale production

during the manufacture of cutting and measuring tools, jigs, dies, and key

components of machines and instruments. Devices with stable and adjustable

end gauges and indicator sensing units are used on jig-boring machines for

precise measurements; also used are lead screws with dials and a vernier, which

are equipped with error-elimination compensators, and graduated shafts with

optical measuring instruments.

There are two types of these machine tools: double-sided (gantry) machines with

a one-movement table and open-sided (single-sided, overhanging) machines

with a two-movement table. In open-sided machines the spindle head moves

only vertically; in the double-sided machines it moves horizon-tally along the

crosspiece, which can travel in a vertical direction.

The manufactured article and the cutting tool on the jig-boring machine are

moved relative to one another along orthogonal coordinates (with linear

displacement accuracy to 2 microns) and polar coordinates (with angular

displacement accuracy to 5 seconds of arc). Sturdy construction is a feature of

jig-boring machines, which have smooth drive motions and accurate balancing

of fast-rotating parts (to reduce vibration).

The machines are installed in insulated areas in which a constant temperature of

20°C is maintained. Jig-boring machines are operated by highly skilled workers.

Jig Boring

Jig Boring Machine Jig Boring

The boring operation can be carried out on lathe and milling machine but the need of accuracy of holes, its quality and relative position of different hole centers is demanded in jig & fixtures. To cope up with this work boring machine are need , which are called “jig boring machine”.

NEED OF JIG BORING MACHINE

The jig boring is a special type of boring process, hence its working principal is just similar to the boring process.

In this process rotating tool is passed over the stationary work. This principal is used for large work pieces, while for small size work pieces tool is kept stationary and work is moved by applying force.

The feed in this process is given with respective to the vertical axis of the hole and its radius.

WORKING PRINCIPLE OF JIG BORING PROCESS

Jig boring machine generally consists of a heavy base and a column.

A spindle head is provided at the top of this column, which is fixed on the guide ways of the column. The spindle is fixed using preloaded antifriction bearings.

The table is arranged on the saddle. It can move in different on the guide ways of the saddle.

Table provides longitudinal motion to the work piece & saddle cross movement to the work piece.

By moving the spindle head up and down, the vertical movement of the spindle is obtained.

CONSTRUCTION &MAIN FEATURES

BED:-the component which base to the machine is called bed it us made from C.I. it support the column, saddle, control penal and whole machine.

COLUMN:-it is also a hollow component made from cast iron. It is supporting the head stock , guide ways and vertical head provides axis for positioning.

head-stock:-it is also called spindle-head.it is fixed on column in front side. Spindle is supported in quill. As this quill is moving up and down side becomes like a telescopic mechanism.

MAIN COMPONENT OF JIG BORING MACHINE

TABLE AND SADLE:- table helps to clamp and hole the work piece in a fixture in required position. Hence t-shaped slots are made in it. The saddle provides possibility of longitudinal motion of the work piece.

PICK-UP DEVICES:- it is attached on the table and saddle. It is helping in controlling various machine operations automatically. Again devices are necessary for accurate measurements.

THERE ARE MAINLY TWO TYPES OF JIG BORING M/C.

Single column jig boring machine

Double column jig boring machine

TYPES OF JIG BORING MACHINE

Single column jig boring machine is used for small size of component.

It is made of plain rotary table, inclined table and square table

It looks like a vertical milling machine, hence it is called vertical milling type jig boring machine.

SINGLE COLUMN JIG BORING MACHINE

The vertical columns are provided at two sides of this machine.

This construction looks like a planer hence it is called a planer type jig boring machine.

It is used for the large weight work pieces.

DOUBLE COLUMN JIG BORING MACHINE

The jig boring machine is specified by following basis;

Distance of spindle axis from column. Maximum distance between spindle face & table. Minimum distance between spindle face & table. Diameter and taper of spindle hole Maximum diameter that can be bored. Maximum weight of work which can be placed. Dimension of working axis of table Maximum table transverse. Horse power of main motor. Horse power of table feed motor. Minimum measuring capacity of dial. Least count of venire caliper. Various spindle speeds.

SPECIFICATION OF JIG BORING MACHINE

The more accuracy is required in measurement taken by jig boring machine and in position, generally different measuring mechanisms are used for taking measurements. They are as under.

1. Precision lead screw system2. Scale and microscope system3. End measurement system4. Electro – magnetic system

SYSTEM OF MEASUREMENT

TOOLS

Based on its construction1. Forged type boring tool.2. Carbide tip tool. Based on shape1. Common type boring tool2. Haviour cut boring tool3. Special boring tool

BORING TOOL MOUNTINGS

1. Boring bar2. Cutter heads3. Facing heads

BORING TOOLS AND MOUNTINGS

For jigs, fixtures and dies. For drilling hole in jig-bushing. To produce compound and progressive

dies. For pilot hole & bushing hole for grinding &

alignment post in stripper or die-set. For grinding the hardened parts.

APPLICATION OF JIG BORING MACHINE

Thank uYours

polaiah