Automation in Manufacturing Unit-1

8/13/2019 Automation in Manufacturing Unit-1

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AUTOMATION

I N

MANUFACTURING


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AUTOMATION

INTRODUCTION

Is an technology by which a process or procedure is

done without human assistance.

Implemented by using an program or instruction with

control system which executes instruction.


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REASONS FOR IMPLEMENTING

AUTOMATION IN MANUFACTURING

INCREASE THE PRODUCTIVITY RATE OF LABOUR

TO DECREASE COST OF LABOUR

SHORTAGE OF LABOUR

IMPROVES WORK SAFETY

TO RESUCE MANUFACTURE LEAD TIME

TO AVOID HIGH COST OF NON AUTOMATION

TO IMPROVE WORKER SAFETY

PRODUCT QUALITY IMPROVEMENT

TO REDUCE MANUFACTURING LEAD TIME


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TYPES OF AUTOMATION

1 . FIX ED A UTO MATIO N

2. PROGRAMMABLE AUTOMATION

3 . FLEXIBLE AU TO MATIO N


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FIXED AUTOMATION

o sequence of processing or assembly operations to be

carried out are fixed by equipment configuration

o difficult to automate changes in design product

o high production rates

o time taking

o during process new products cannot be processed


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PROGRAMMABLE AUTOMATION

Production equipment is designed with the capabilityto change the sequence of operations

Controlled by an program consists of set of codedinstructions can be read and implemented by system

New program or codes can be entered to produce newproducts

High investment

Low production rates, low & medium volume

production Suitable for batch production

Example: numerical control machines(nc)


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FLEXIBLE AUTOMATION

Extension of programmable automation

Developed to minimize time loss between change

over of batch production from 1 to another

No loss of production in reprogramming & altering

Very high investment

Continuous production with variable products

Example: CNC Machines


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ADVANTAGES OF AUTOMATION

High rate of production

Requires less number of workers

Produces high quality of products

Production time period is low

General working conditions are improved

Heavy jobs can be handled easily

Adaptability to CAD/CAM

Shorter lead times


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DISADVANTAGES OF AUTOMATION

Initial cost is very high

Maintenance cost

Requires several complex control systems

Skilled workers

Break down stops whole production

Substantial preplanning is required


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STRATEGIES IN AUTOMATION

1. SPECIALIZATION OF OPERATIONS

2. COMBINED OPERATIONS

3. SIMULTANEOUS OPERATIONS

4. INTEGRATION OF OPERATIONS

5. INCREASED FLEXIBILITY

6. IMPROVING MATERIAL HANDLING

7. ONLINE INSPECTION

8. PROCESS CONTROL & OPTIMIZATION

9. PLANT CONTROL OPERATIONS

10. COMPUTER INTEGRATED MANUFACTURING (CIM)


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1. Power - to accomplish the process and operate

the automated system

2. Program of instructionsto direct the process

3. Control system

to actuate the instructions

Automation is the technology by which a process or

procedure is accomplished without human assistance.

Basic elements of an automated system :


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BASIC ELEMENTS OF AUTOMATION

PROGRAM OF

INSTRUCTIONS

CONTROL

SYSTEMPROCESS

POWER


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Electricity -

The Principal Power Source

Widely available

Can be readily converted to alternative forms,

e.g., mechanical, thermal, light, etc.

Low level power can be used for signal

transmission, data processing, and

communication

Can be stored in long-life batteries


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Power for the process

To drive the process itself

To load and unload the work unit

Transport between operations

Power for automation Controller unit

Power to actuate the control signals

Data acquisition and information processing


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Program of Instructions

Example: CNC part program

During each step, there are one or moreactivities involving changes in one or more

process parameters

Examples:

Temperature setting of a furnace

Axis position in a positioning system

Motor on or off

Set of commands that specify the sequence of

steps in the work cycle and the details of eachstep


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Control System Two Types

1. Closed-loop (feedback) control system

a system in which the output variable is

compared with an input parameter, and

any difference between the two is used todrive the output into agreement with the

input

2. Open-loop control system operateswithout the feedback loop


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Closed loop control system

open loop control system


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Temperature instructions

Example for closed loop control system


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Example for open loop control system


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Levels of Automation

1. Device level actuators, sensors, and other

hardware components to form individual control

loops for the next level

2. Machine level CNC machine tools and similar

production equipment, industrial robots,material handling equipment

3. Cell or system level manufacturing cell or

system

4. Plant level factory or production systems level

5. Enterprise level corporate information system


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Levels of Automation


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PNEUMATIC SYSTEM


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Hydraulic system


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Pneumatic system consists of

Motor driven compressor

Air receiver

Directional control valve (DCV) PNEUMATIC cylinder


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C

WEIGHT

DIRICTIONAL

CONTROL

VALVEAIR

RECEIVER

MOTOR

MOTOR

CONTROL

PNEUMATIC SYSTEM


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HYDRAULIC SYSTEM

The basic hydraulic system essentially consists of apump and a cylinder

Hydraulic piston is lifted by a hydraulic pump driven

by a electric motor

System consists of a closed-loop piping network

With a fluid transferred from a storage tank to one

side of piston

Pump converts a mechanical force to hydraulic powerand fluid is drawn from the tank


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HYDRAULIC SYSTEM

hydraulic system has significant advantageover pneumatic system in carrying loads

Range from 35 to 200 mpa

Main components are Hydraulic power supply

Electro hydraulic servo valve

Sump or tank

Hydraulic motor


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HYDRAULIC SYSTEM

PPress

ure Control

valve

FILTER

WEIGHT

PISTON

FLUID TANK


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A pressure regulation/relief valve protects the

system from high pressure

Is essential to spill excess fluid back to tank

The cylinder uses the moving oil to do work

and the cylinder movement is controlled by a

valve

The control valve directs the oil to allow

supply of oil from the pump to and from

cylinder


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AUTOMATION IN

MACHINE TOOLS


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Machine tool is defined as the machinery

used to obtain the desired properties or

geometry of the metallic or non-metallic

materials by performing various

operations

Automated machine tool is nothing but

NC(numerical control) CNC (computer

numerical control) Mostly used is CNC


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Principle functions of CNC machines

MACHINE TOOL CONTROL IMPROVED PROGRAMMING

AND WORKING FEATURES IN-PROCESS COMPENSATION

DIAGNOSTICS


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Machine tool control

This is important function of the CNC system Deals with steps and various functions of process

which are used to convert the part program

instructions into machine tool

For this conversation process is done by using the

computer interface and servo system

TYPES

1. HYBRID CNC

2. STRAIGHT CNC


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HYBRID CNC

Consists mainly 2 parts

1. Soft-wired computer

2. Hard wired logic circuitsThe hard wired circuits perform the machine tool

feed rate generation and circular interpolation

The remaining control functions and duties areassociated by the computer


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Tapereader

from

initial

program

inputinterp

olationoffsets

X Y Z

motion

Interfacing

unit

feedback

HYBRID CNC


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STRAIGHT CNC

Consists one computer to perform all NC

functions

The only hard-wired components arerequired to interface the computer with

machine tool and operator task


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STRAIGHT CNC

TAPE

READER FOR

INTIALPROGRAM

I

N

PU

T

COMPU

TATIONOFFSETS S

E

NS

O

R

S

MOTION

FEEDBACK


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IMPROVED PROGRAMMING AND WORKING

Includes1. Graphical display of tool path and verification of

tape

2. Use of specially written subroutines

3. Manual data & input method

4. Local storage of more than one part diagram

5. Interpolation techniques

6. Editing the program


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INPROCESS COMPENSATION

Recalculating and analysis of axis positioning

Offset adjustments

Accurate calculation of predicted tool life

Use of specially written sub programs

SI & METRIC units

Large storage system having more than one part

program


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DIAGNOSTICS

This function is available in modern CNC machine

It helps in maintenance and repair of the system

Its functions are

1. To minimize downtime

2. Warn about forthcoming failure of a certain

components


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MECHANICAL FEEDERS

Used in automation are

1. Centrifugal feeders

2. Drum feeders

3. Barrel feeders

4. Rotary selector ring feeders

5. Elevator feeders

6. Blade feeders


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MECHANICAL FEEDER


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CENTRIFUGAL FEEDER


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DRUM FEEDER


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ELEVATOR FEEDER


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AUTOMATIC TOOLCHANGING


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M-TAB CNC


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BED CNC


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A variety of machining process or operationmay done for finishing a particular part

So variety of tool are needed to do particularoperation

These tools are positioned on tool drum of themachine when a particular operation is done

on the part

Tool drum rotates to change the tool positionby means of ATC mechanism

This program helps to exchange the tool in thespindle and in drum


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AUTOMATIC TOOL CHANGER


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ADVANTAGES OF ATC

Reduces idle time

Usually takes 5 to 7 seconds

Identification of tool (done by codes)

Tool transfer is done by the reciprocating motion

of spindle and magazine

CLASSIFICATION OF TOOL


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CLASSIFICATION OF TOOL

CHANGE

1. According to kind of cutting tools

Single tool heads

Multi tool heads

Special tool heads

2. According to tool position

Horizontal type Vertical type


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SINGLE TOOL, MULTI TOOL

AUTOMATIC TOOL CHAGER


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AUTOMATIC TOOL CHAGER

HORIZONTAL



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VERTICAL


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According to system tool exchanger

1. Without tool change arm

2. With tool change arm

3. With tool parking position

According to position of axes of spindle

1. Parallel axes

2. Intersecting axes


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CNC MACHINE TOOLS

Automation in Manufacturing Unit-1

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