gate industrial engineering book

8/10/2019 GATE Industrial Engineering Book

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Industrial Engineering

For

Mechanical Engineering

By

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Syllabus Industrial Engineering

THE GATE ACADEMY PVT.LTD. H.O.: #74, KeshavaKrupa (third Floor), 30th

Cross, 10th

Main, Jayanagar 4th

Block, Bangalore-11

080 65700750 i f @th t d C i ht d W b th t d

Syllabus for Industrial Engineering

Production Planning and Control: Forecasting models, aggregate production planning,

scheduling, materials requirement planning.

Inventory Control: Deterministic and probabilistic models; safety stock inventory

control systems.

Operations Research: Linear programming, simplex and duplex method, transportation,

assignment, network flow models, simple queuing models, PERT and CPM.

Analysis of GATE Papers

(Industrial Engineering)

Year Percentage of marks Overall Percentage

2013 6.00

7.85

2012 5.00

2011 0.00

2010 12.00

2009 11.00

2008 9.33

2007 5.33

2006 10.67

2005 11.33


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Contents Industrial Engineering

THE GATE ACADEMY PVT.LTD. H.O.: #74, Keshava Krupa (third Floor), 30th

Cross, 10th

Main, Jayanagar 4th

Block, Bangalore-11

080 65700750 i f @th t d C i ht d W b th t d P i

C O N T E N T S

Chapter Page No.

#1. Production, Planning and Control 1 23

Forecasting 1 3

Statistical Forecasting 4 5

Production Planning and Control 5 7

Solved Examples 7 14

Assignment 1 15 16

Assignment 2 17 18

Answer Keys 19

Explanation 19

23

2. Inventory Control 24 48

Inventory 24 25

Inventory Models 25 37


Assignment 1 42 43

Assignment 2 43 44

Answer Keys 45

Explanations 45 48

3.Operations Research 49 119 Introduction 49

Linear Programing 49 52

Characteristics of Corner Points 52 56

Simplex Method 56 62

Transportation Problem 62 82

Assignment Problems 82 84

Algorithms to Solve Assignment Model 84 85

Optimality Test of Total Opportunity Cost Matrix 86 89

Queuing Models 89 97

CPM and PERT 97

Methodology of CPM 98 Terminology used in CPM/PERT 98 99

Rules of Constructing Network Diagram 100

Difference Between CPM and PERT 100 101


Assignment 1 110 111

Assignment 2 112 114

Answer Keys 115

Explanations 115 119


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Contents Industrial Engineering

THE GATE ACADEMY PVT.LTD. H.O.: #74, Keshava Krupa (third Floor), 30th

Cross, 10th

Main, Jayanagar 4th

Block, Bangalore-11

080 65700750 i f @th t d C i ht d W b th t d P ii

Module Test 120 130

Test Questions 120

125 Answer Keys 126

Explanations 126 130

Reference Books 131


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Chapter 1 Industrial Engineering


Cross, 10th

Main, Jayanagar 4th

Block, Bangalore-11

: 080 65700750 info@thegateacademy com Copyright reserved Web: www thegateacademy com Page 1

CHAPTER 1

Production, Planning and Control

Forecasting

The main purpose of forecasting is to estimate the occurrence, timing or magnitude of future

events. Once, the reliable forecast for the demand is available, a good planning of activities is

needed to meet the future demand. Forecasting thus provides the input to the planning and

scheduling process.

Types of Forecasting

Long range forecast

Long range forecast consists of time period of more than 5 years. The long range forecasting

is useful in following areas

Capital planning

Plant location

Plant layout or expansion

New product planning

Medium range forecast

Medium range forecast is generally from 1 to 5 years. The medium range forecasting is

useful in the following areas

Sales planning

Production planning

Capital and cash planning

Inventory planning

Short range forecast

The short range forecast is generally for less than 1 year

Purchasing

Overtime decision

Job scheduling

Machine maintenance

Inventory planning


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Block, Bangalore-11


Quantitative Methods of Forecasting

1. Extrapolation

Extrapolation is one of the easiest ways to forecast. In this method, based on the past fewvalues of production capacity, next value may be extrapolated on a graph paper.

2.

Simple moving average

In this method, mean of only a specified number of consecutive data which are most recentvalues in the series is calculated. Forecast for ( t+1)thperiod is given by

Where,Di= Actual demand for ithperiod & n= Number is periods included in each average

3.

Weighted moving average

In this method, more weightage of given to the relatively newer data. The forecast is theweighted average of data.

Where, Wi= Relative weight of data for i thperiod and

It may be noted that when more weight is given to the recent values, the forecast is nearerto likely trend. Weighted moving average is advantageous as compared to simple movingaverage as it is able to give more importance to recent data.

Example

The value of moving average base n lies between

A.

0 & 1

B. 2 & 10

C. -1 & 1D. None of the above

[Ans: A]

4. Exponential smoothing

In the exponential smoothing method of forecasting, the weightage of data diminishesexponentially as the data become older. In this method all past data is considered. The

weightage of every previous data decreases by (1-), where is called as exponentialsmoothing constant.

( ) ( ) ( ) Where,

Di= One period ahead forecast made at time t

Dt= Actual demand for tthperiod

Smoothing constant (0 )Comments regarding Smoothing constant Smaller is the value of , more is the smoothing effect in forecast.

Higher value of gives more robust forecast and response more quickly to changesHigher value of gives more weightage to past data as compared to smaller value


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Example

The limitation in moving average method for forecasting cans

A.

Demand pattern is stationaryB. Demand pattern is varyingC. Demand pattern has a constant mean value

D. Both A & C

[Ans: D]

Example

ind relationship between exponential smoothing coeff () and N, so that responses are sameSolution

Average life of data S = 0 (N )

or, average life of data =()

S =

()()

(N )

= ( N ) . . . . (i)

Average life of data for exponential smoothing

S 0* * ( ) * ( )

+ . . . . . . . . + (N )( )

+ . . . .. = ( ) ( ) ( )+ . . . . . . . . [( ) ( ) ( ) ] . . . . (ii)

Now; multiplying (ii) by (1 ) and subtracting from (ii) we get [( ) ( ) ( ) ( ) ]

( )S [( ) ( ) ( ) ]S[ ( )] [( ) ( ) ( ) ( ) ]

, () ( ) ()

,

()From (i) & (iii)

2 N , Or, N

Or, (N) , Or,


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Block, Bangalore-11


Statistical Forecasting

Statistical forecasting is based on the past data. We evaluate the expected error for the statistical

technique of forecasting. Some common regression functions are as follows

Let

Ft= Forecast for time period t

dt= Actual demand for time period t

t= time period

1. Linear Forecaster

Ft= a+bt

Where a and b are parameters

2.

Cyclic Forecaster

Ft= a+ uCos (2/N)t + vSin (2/N)t

Where a, u and v are parameters and N is periodicity

3. Cyclic Forecaster with Growth

Ft= a+ bt+ uCos (2

/N)t + vSin(2

/N)t

Where a, b, u and v are parameters and N is periodicity

4.

Quadratic Forecaster

Ft=a +bt+ct2

Where a, b and c are parameters

Accuracy of Forecast

Many factors affect the trend in data therefore it is impossible to obtain an exact right forecast.Below are the tools that are used to determine the error in the forecasted value.

1. Mean Absolute Deviation MAD)

This is calculated as the average of absolute value of difference between actual and

forecasted value.

MAD = ||

Where,

Ft= Actual demand for period t

Dt= Forecasted demand for period t

n= number of periods considered for calculating the error


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2.

Mean Sum of Square Error MSE)

The average of squares of all errors in the forecast is termed as MSE. Its interpretation is

same as MAD.

( )

3.

BIAS

BIAS is calculated as the average of the difference between actual and forcast value. A

positive value means under estimation and negative value means over estimation.

( )

Production Planning and Control

Production planning and control is one of the most important areas of industrial management.

This aims at achieving the efficient utilization of resources in any organization through planning,coordination and control of production activities.

Phases of PPC

Preplanning

Product development and design

Process design

Work station design

Factory layout and location

Planning Different Resources

Material

Method

Machine

Men

Control

Inspection

Expedition

Evaluation

Dispatching

Production Planning and Control Steps


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1.

Routing

Routing is the process of deciding sequence of operations (route) to be performed during

production process. The main objective of routing is the selection of best and cheapest wayto perform a job. Procedure for routing is as follows

Conduct an analysis of the product to determine the part/ component/ sub-assemblies

required to be produced.

Conduct the analysis to determine the material needed for the product.

Determine the required manufacturing operations and their sequence.

Determine the lot size.

Determine the scrap.

Estimate product cost.

Prepare different forms of production control.

2.

Scheduling

Scheduling involves fixing the priorities for different jobs and deciding the starting andfinishing time of each job. Main purpose of scheduling is to prepare a time-table indicatingthe time and rate of production, as indicated by starting and finishing time of each activity.

Scheduling will be discussed in detail in next section.

3.

Dispatching

Dispatching is the selection and sequencing of available jobs to be run at the individualworkstations and assignments of those jobs to workers. Functions of dispatching are asunder.

Collecting and issuing work centre

Ensuring right material, tools, parts, jigs and fixtures are available.

Issues authorization to start work at the pre-determined date and time.

Distribute machine loading and schedule charts

4.

Expediting

This is the final stage of production planning and control. It is used for ensuring that thework is carried out as per plans and due dates are met. The main objective is to arrest

deviations from the plan. Another objective is to integrate different production activities tomeet the production target. The following activities are done in expediting phase

Watching the progress of the production process.

Identification of delays, disruptions or discrepancies.

Physical control of work-in-progress through checking

Expediting corrective measures.

Coordinating with other departments.

Report any production related problems.


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gate industrial engineering book

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