Manufacturing: Engineering, Management and Marketing

By S.O.T Ogaji, M. T. Lilly and S.D. Probert

In a developing country like Nigeria, the available land is plentiful but is relatively more expensive in city areas like Abuja, Lagos, and Port Harcourt. Hence, to reduce cost, land outside the cities is often sought. In Nigeria, labor is cheap per hour, but it becomes more expensive as one moves toward the cities. Nevertheless, to reduce overall costs, transportation costs should be reduced, so the site of the factory should be close to a large market for its products. In developed countries, government policies influence significantly the locations of factories. For instance, factories are set up in high-unemployment areas to comply with the national development policy for the country. In Nigeria, the sitting of a factory is often based on political rather than management considerations. Therefore, many government-owned companies exist in economically nonviable locations, for example, the refinery and the fertilizer plant at Kaduna. However, private investors prefer to start companies in their own localities. Reliable electricity supplies and an adequate transportation infrastructure are essential for most companies. Unfortunately, in Nigeria, companies too often have to provide standby generators, thereby increasing production costs. This is one of the reasons why made in Nigeria goods tend to be more expensive than the corresponding imported ones, despite far lower local labor costs.
This textbook which provides desirable service to students, engineers, managers and politicians covers an extensive range of topics that includes but not limited to essentials of management, optimal maintenance of equipment, financial management, cost/benefit analysis, creative thinking, entrepreneurship, operation research, queuing theory, the factory environment, depreciation replacement theory, marketing, automation and motivation.

• Language: English
• Publisher: Partridge Publishing Africa
• Release date: Sep 9, 2015
• ISBN: 9781482808421

S.O.T Ogaji

Macaulay Thomas Lilly B. Eng (A.B.U., Zaria, Nigeria), PhD (Liverpool, U.K.), FNSE, FIMechE, MISPON, MIIE The Author had his first degree in Mechanical Engineering in 1977 from Ahmadu Bello University, Samaru, Zaria, Nigeria. During the National Youth Service Corps (N.Y.S.C.) the Author worked as a Maintenance Engineer- in- training, testing Aircraft parts for cracks at Nigerian Airways Limited, Ikeja, Lagos. After the service he joined Nigerian Engineering Works Limited (NEW) as a Production Engineer in-charge of producing Room Air-conditioners. In 1980 the Author joined the Rivers State University of Science and Technology as a Lecturer. He had his Ph. D degree in 1986 at the University of Liverpool, Liverpool, England. At the moment the Author is a Reader (Associate Professor) in the Department of Mechanical Engineering of the Rivers State University of Science and Technology, Port Harcourt. The Author is a COREN registered Engineer and he is also a Fellow of Nigerian Society of Engineers (NSE). Stephen O.T. Ogaji B.Tech, M.Tech, PgDipBS (Nigeria), PhD (Cranfield, UK), PGCert (Cranfield, UK) CEng, FNSE, FHEA, MIMechE Following the award as best Mechanical Engineering student in1992, Stephen Ogaji’s experience ranged from university lecturing to oil field operations and logging services with Schlumberger International Oil Services in Middle Eastern countries. He held a number of leadership positions in both academic and public institutions. In addition to membership of relevant professional engineering institutions, he acts as a peer reviewer for the Journal of Engineering for Gas Turbine and power, Applied Soft Computing Journal (ASOC), ASME Turbo Expo conferences amongst others. Stephen has contributed to the publication of over 100 academic papers and is a co-author of a textbook on Fuels & Combustion in Heat Engines. Currently, Stephen is the Director of the globally recognised Thermal Power MSc course at Cranfield University, UK, where he is also involved in teaching, supervision, national and international research and development projects. His research interests are focused on gas turbine performance, environmentally-friendly power cycles, gas turbine combustion, emissions, life cycle assessment and gas turbine fault diagnostics. Doug S. Probert MA, DPhil, DSc, CEng Prof Doug Probert is a graduate of Aeronautic Engineering and Physics from Oxford and Cambridge University, respectively. Doug lectured at Oxford and Swansea universities before he joined Cranfield University as a Professor of Applied Energy where he remained for over twenty-five years. He was the editor of Applied Energy Journal for over thirty-two years and currently serves as editor emeritus. He is the co-author/author of more than nine hundred papers in the refereed professional literature and a winner of five national prizes.

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Copyright © 2015 by M. T. Lilly, S. O.T. Ogaji & S. D. Probert

ISBN:   Hardcover   978-1-4828-0840-7

             Softcover     978-1-4828-0841-4

             eBook          978-1-4828-0842-1

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CONTENTS

Preface

Section 1: Management And Administration

Chapter 1: Facilities. Layout And Materials Handling

1.0 Introduction

1.1 Siting of a company

1.2 Plant Layout

1.3. Material-handling systems

1.4 Materials handling during production

1.5 Materials handling in warehousing and storage

1.6 Storage-space determination

Chapter 2: Forecasting

2.0 Introduction

2.1 Short-term forecasting methods

Chapter 3: Decision-Making

3.0 Introduction

3.1 Principles of decision-making

3.2 Selection of decision-making techniques

3.3 The make-or-buy decision

3.4 Decision trees

3.5 Replacement decision-making

3.6 Types of replacement problems

Chapter 4: Linear Programming

4.0 Introduction

4.1 Graphical method

4.2 Simplex method

4.3 Transportation method

4.4 The assignment problem

4.5 Dynamic programming

Chapter 5: Queuing Theory

5.0 Introduction

5.1 Types of queuing problems

Chapter 6: Network Analysis

6.0 Introduction

6.1 Useful terms in network analyses

6.2 Drawing networks

6.4 Generalised rules for analyses of networks

Chapter 7: Management Pioneers

7.0 Introduction

7.1 Pioneers of scientific management

7.2 Principles of management

7.3 Activities of management

Chapter 8: Organisational Principles

8.0 Introduction

8.1 Span of control

8.2 Authority in an organisation

Chapter 9: Industrial Ownership

9.1 Business regulations

9.2 Types of business ownership

Section 2: Production And Marketing

Chapter 10: Production Analysis

10.0 Productivity

10.1 Factors affecting productivity

10.2 Productivity in manufacturing industries

Chapter 11: Production Planning And Control

11.1 Production planning and control problems in various department of the business

11.2 Purpose and scope of production planning and control (PPC)

11.3 Progress monitoring and control

11.4 Capacity planning

Chapter 12: Quality Control And Reliability

12.0 Introduction

12.1 Functions of a quality-control department

12.2 Quality-control indices in common use

12.3 Statistical quality control (SQC)

12.4 Reliability

Chapter 13: Work Study

13.0 Introduction

13.1 Work measurement and method study

13.2 Rating

13.3 Useful equations with respect to work and time study

13.4 Further comments on calculating standard times

Chapter 14: Ergonomics

14.0 Introduction

14.1 Production system

14.2 Factors that result in good working conditions

Chapter 15: Stock Control

15.0 Introduction

15.1 Stock-control systems

15.2 Stock costs

15.3 Stock-control models assuming certainty of variables

15.4 Determination of economic order quantity (EOQ)

15.4.1 Effect of price discounts

15.5 Economic production quantity (EPQ) model

15.6 Realistic stock-control models

15.7 Economic-order quantity with shortage or stock-out

15.8 Economic-production quantity model with shortages

15.9 Stock classification

Chapter 16: Value Analysis

16.0 Introduction

16.1 Introduction of new products to the market

Section 3: Finance

Chapter 17: Sources Of Finance

17.0 Introduction

17.1 Means of Financing

Chapter 18: Accounting And Bookkeeping

18.0 Introduction

18.2 Bookkeeping

Chapter 19: Financial Planning And Control

19.0 Introduction

19.1 Major objectives of financial planning and control

19.2 Cost control

19.3 Marginal costing and break-even analyses

19.4 Variance analysis and standard costing

19.5 Sources and uses of funds

19.6 Profit planning

19.6.0 Introduction

19.7 Appraisal of resources

19.8 Budgetary control

Chapter 20: Wages And Salaries Administration

20.0 Introduction

20.1 Types of wage structure

20.2 Systems of wage payment

20.3 Financial incentives and motivation

20.4 Financial incentives based on work-measurement data

Section 4: Personnel

Chapter 21: Personnel Engagement

21.0 Introduction

21.1 Recruitment, selection, and placement

21.2 Work specification

Chapter 22: Job Evaluation And Employee Motivation

22.0 Introduction

22.1 Current job-evaluation methods

22.2 Successful job evaluation

22.3 Detailed systems of job evaluation

Section 5: Modern Manufacturing Systems

Chapter 23: Modern Manufacturing Systems

23.0 Introduction

23.1 Six Sigma

23.2 The kanban manufacturing system

Solutions To Selected Problems

References

Appendix I

Appendix II

PREFACE

Production management and engineering makes a crucial contribution to the economic success of any industrialised society. As such, this basic text provides desirable advice to engineers, managers and politicians. It can be used for undergraduate and postgraduate teaching or as contributory information for an intensive 3-day module when presented as a short course for those already in employment. The book is also useful to practising engineers. Among the topics discussed are:-

The essentials of management, trade unionism, optimal maintenance of equipment, successful teams: loyalty, leadership, effective meetings financial management, cash flows, cost/benefit analysis creative thinking, patents, entrepreneurship operation research linear programming transportation, simplex method etc queuing theory, the factory environment Work-study Time Study Depreciation Replacement theory marketing automation motivation.

This book is the out come of many years of teaching production engineering, engineering management, operation research and the engineer-in-society at undergraduate and postgraduate level. There are many worked examples to assist the reader, in understanding the content.

GLOSSARY of terms used in the present context

ABC analysis: This is a process of classifying items in a stock in decreasing order of annual monetary value. The array is split into three classes, called A, B and C. Class A contains items (usually very few) which have the highest annual financial value and require the most attention (i.e. a high degree of security). Class C items have low financial values, but are usually numerous and require least attention, class B contains all offer items.

Annual equivalent worth: This concept is used for comparing and deciding between alternative investment options.

Autocorrelation: Fluctuations which occur at random (i.e. with no periodic cycle) but tend to persist for an appreciable time, so that even though a large set of data may be normally distributed about a mean, the value of any one number in the sequence is more likely to be close to its preceding number than to be completely independent of neighbouring numbers.

To account for autocorrelation in forecasting requires more complex calculations, than would normally be warranted for dealing with individual stock items. In practice, this refinement is rarely found worthy of the computational difficulties encountered.

Basic feasible solution: It is a basic solution to a linear programming problem with equations which also satisfies the non-negativity constraints.

Basic solution: This is the solution to a system of m simultaneous linear equations with n unknowns linear programming problem; if an m x m non-singular matrix exists and if all the n-m variables associated with the remaining columns of this matrix are set equal to zero.

Basic time: This is the time an operator used to perform an operation (i.e. the directly observed time) multiple by the effectiveness rating for the operator.

Binomial distribution: It states that the probability that for a random system of sample size n will contain exactly k defectives is P(x = k) = 3382.png where the mean is equal to np and the variance is equal to np(1-p).

Book value: It is the difference between the original cost and the accumulated depreciation of a facility (asset).

Capacity: This is the time available on a machine for the required production purpose.

Cycle time: This is the time required to produce a unit of the designed component or product

Cyclic variations: Changes in the basic pattern which occur over a relatively short period of time and show evidence of periodicity. A number of cycles, having different frequencies, may be superimposed, to make the variations become very clear.

Effectiveness: A quantitative measure which can be used to evaluate the level of achieved performance in relation to a prescribed standard, set of criteria or objective.

Elemental time: The time required to complete a single task in a process.

Flyback timing: Flyback implies a ‘return’. In this type of timing, elemental times are obtained directly.

Grade point: The acceptable level of performance of a worker.

Group technology: The effective manufacturing method brings together parts or components, which will experience similar machining process, facilitating improved production planning and machine loading.

Iso-profit line: A line joining all the points of equal profit.

Load centre: The centre of gravity of an object.

Loading: Process of allocating period(s) of time for the use of a machine (or other production facility).

Moving-average: The series of arithmetic average obtained by averaging the last set of successive terms in a time series; these terms being spaced at equal intervals.

Moving-average evaluation: A procedure by which members of a sequence (e.g. of observations) are replaced by arithmetic averages of a series of consecutive members of the sequence; the series being symmetric about, and including the member whose moving-average is being calculated.

Non-basic solution: A solution to a linear-programming problem obtained by the Simplex method and whose value has been arbitrarily set equal to zero.

Normal distribution: This is a continuous frequency distribution of a set of observations of infinite range represented by the equation 3391.png , Where f = function, 3398.png = rate of failure, 3406.png = standard deviation

Objective function: This is a combination of the influential parameters. Its value is to be maximised or minimised subject to the constraints of the problem. For a linear-programming problem, the objective function is a linear combination of the influential parameters.

Poisson distribution: A probability distribution of the form f(x) = mxe-m/x! where the mean and the variance are equal, and are equal to m, and x is.

Producing to stock: This is the process of manufacturing to maintain at least the predetermined minimum amount in the store, the goods will subsequently be supplied to customers.

Random variation (often called noise): An unpredictable fluctuation, which occurs around the general pattern of the sequence and often confuses the identification of the pattern, so that it is difficult to assign a truly representative variation in the data.

Relayout: Rearranging the facilities (old and/ or new) in an existing production or manufacturing setup or layout.

Safety stock: This is the quantity of stock required to be readily available in order to protect the holder against fluctuations in demand and/ or supply. It is used to avoid being out seasonal variation (a specific case of the cyclic variation) of stock thereby immediately reducing productivity.

Standard deviation: The square root of the ratio of the sum of the squared deviations from the mean of a set of the observations to the sample size. It is equal to the positive square root of the variance.

Standard time: It is the period required by an average operator to perform the specified task.

Stock-out: This is the situation when a company runs out of raw material and hence stops production.

Store: A place or space where materials are kept.

Trend: A tendency to move in an identifiable direction.

Variance: The ratio of the sum of the squared deviations from the mean of a set of observations to the sample size.

Warehousing: The process of keeping materials in a store.

Work-study: A generic term for those techniques, particularly method study and work measurement, which are used in the examination of the effectiveness of applied human effort. It leads systematically to an investigation of the factors which affect the efficiency and economics of the work undertaken, in order to try to achieve an improvement. In the present context, work-study means achieving a quantitative understanding of the process of measuring the amount of work entailed in completing a job.

Nomenclature

Section One

MANAGEMENT AND ADMINISTRATION

CHAPTER 1

FACILITIES. LAYOUT AND MATERIALS HANDLING

1.0 Introduction

The aim should be to locate the factory optimally in an area where readily qualified labour is available and there is a ready market for the goods produced. The plan of the factory and the layout of its facilities influence its effectiveness.

1.1 Siting of a company

To obtain a feasibility study for the establishment of a manufacturing factory, the selection and cost of its location used must be assessed. The factors that affect its location are

(i)  availability of land and its cost

(ii)  availability of suitably qualified local labour and its likely cost

(iii) nearness to markets for the end product of the factory

(iv)  pertinent government policies and degree of security that apply locally

(v)  local availability of services like transportation, electricity, natural gas, or potable water.

In a developing country like Nigeria, the available land is plentiful, but is relatively more expensive in city areas like Abuja, Lagos, and Port Harcourt. Hence, to reduce cost, land outside the cities is often sought. In Nigeria, labour is cheap per hour but it becomes more expensive as one moves towards the cities. Nevertheless to reduce overall costs, transportation costs should be reduced, so the site of the factory should be close to a large market for its products. In developed countries, government policies influence significantly the locations of factories. For instance, factories are set up in high-unemployment areas to comply with the national development policy for the country. In Nigeria, the siting of a factory is often based on political rather than management considerations. Therefore, many government-owned companies exist in economically non-viable locations, for example, the refinery and the fertiliser plant at Kaduna. However, private investors prefer to start companies in their own localities.

Reliable electricity supplies and an adequate transportation infrastructure are essential for most companies. Unfortunately, in Nigeria, companies too often have to provide standby generators, thereby increasing production costs. This is one of the reasons why made-in-Nigeria goods tend to be more expensive than the corresponding imported ones, despite far lower local labour costs.

1.2 Plant Layout

Production problems associated with poor layout can be the

tendency of the control to be more complicated

congestion of personnel and materials

production-line bottlenecks

excessive rehandling of materials

longer transportation lines

greater probability of accidents

lower employee performances

Wise layout should facilitate overcoming such problems.

1.1.1 Types of plant layout

The aim should be the minimisation of production cost while simultaneously satisfying both technical and management requirements. Some of the challenges are

producing the desired rate of output

minimising the production of scrap

avoiding the occurrence of accidents

maximising equipment usage

reducing work in progress

reducing transportation costs incurred

making each worker more responsible and hence productive.

Achieving these objectives may require either modifying existing plant or introducing new plant.

1.1.1.1 New layout design

A simple formula that can be used to calculate the number N of machines of the same type that may be required in the layout is N = TP/HC

where T = standard time per unit end product per machine (hours)

P = required production of end products per day

H = number of production hours per day

C = utilisation factor for the plant.

So, for example if (i) a product requires processing on a lathe for 15 minutes; (ii) the required daily production P of the product is 100 units, (iii) the company runs 2 shifts per day, of 8 hours each; and (iv) the plant utilisation factor C is 0.75, calculate the number of machines required to satisfy the daily requirement.

Solution: Standard time per unit, T = 0.25 hr

Required production per day, P = 100

Number of production hours per day, H = 8 × 2 = 16

Therefore, number of machines, N required = (0.25 × 100) / (16 × 0.75) = 2.08

In practice, it will be necessary to install 3 machines.

From the calculation of the required number of machines and ensuring ergonomic principles, the required space is calculated. As stated by Reed¹ in determining the floor area required, the following factors need to be considered:

area required for each machine and its operation

storage volume requirement for tools, jigs, and fixtures

each operator’s space requirement

space for incoming-material storage

space for handling facilities

space for machine servicing and maintenance requirements

each plant’s service requirements, such as illumination and ventilation.

Space is also required for other activities such as inventory; materials and quality control; storage; transport; reception and dispersal areas for goods; plant maintenance; canteen, washrooms and toilets; and administrative offices.

Departmental Arrangements

(I) Flow pattern of a product: This important consideration for the effective operation of a facility is affected by

number of components in the manufactured product

number of operations required in the manufacture of each component

sequence of these operations

number of sub-assemblies

total number of units to be produced

necessary flows of products between work areas

amount and shape of space available

types of processes

types of flow patterns

location of service areas

location of production departments

material storage

flexibility desired

the building’s configuration.

Some of these factors may be difficult to quantify. An important factor influencing flow efficiency is the total distance travelled multiplied by the volume.

(II) Non-computerised methods¹

Three of the non-computerised quantitative methods for departmental layout arrangements are

spiral analysis

straight-line analysis

travel charting

(III) Computerised methods²,³,⁴

Several of the computerised methods commonly applied in industrial applications are

-CRAFT (Computerised Relative Allocation of Facilities Techniques)

CORELAP (Computerised Relationship Layout Planning)

ALDEP (Automated Layout Design Program)

COFAD (Computerised Facility Design)

1.1.1.2 Improved layout design

There are four possible re-layout challenges:

new layout, no restrictions at all

new layout within an existing building

new replacement layout to be phased into an existing layout

extension/reduction of an existing layout

In introducing a new manufacturing-plant layout, the principal physical constraint is that of the shape and size of each work - centre. The rearrangement of an existing layout adds a whole new dynamic character to the layout problem. The dynamic influence arises when considering withdrawing old manufacturing facilities. Also, installing improved technological facilities needs to be undertaken with the least disruption to production.

1.1.2 Factors leading to layout changes

These can result from improved manufacturing-technologies becoming available and/or changes in the market demand.

Changes in the market and products

Batch manufacture is typified by frequently changing products, on the same production line. The substitution of electronics for electromechanical controls has revolutionised plant layout in modern factories. In the developed world, there is a general tendency for manufacturing companies to move into higher added-value production. Thus more complex products, relying more frequently on advanced manufacturing technology, are appearing in the desire for higher profitabilities. As individual wages tend to be higher in developed world, more robots are used there to replace humans.

Changes in Manufacturing Technology

The problem of modifying or replacing an existing layout is more complicated when the production is carried out in batches, because it is this type of manufacturing that has seen the introduction of substantially new systems and procedures based upon the use of advanced technology. Amongst the examples of this type of change are

the introduction of group-technology-based manufacture in the 1960s and 1970s

the move from numerical control (NC) to computerised numerical control (CNC) and in the 1980s to direct numerical control (DNC)

the introduction of robotics and automated guided vehicles (AGVs) as the basis of computer-controlled materials handling

the development of flexible manufacturing-processes using DNC, AGV, and robotics technology

the availability of more powerful interactive computers for production planning, online monitoring and control, as well for as automated quality assurance.

Batch manufacturing layouts are undergoing significant technological and managerial transformations as the move is made from traditional to advanced manufacturing systems. These changes are accompanied by modifications in the layout of facilities.

1.1.3 Classic layouts of production equipment in engineering factories

Three traditional layouts are illustrated in figures 1.1 to 1.3 are common.

One-off layout

For large one-off products, the product remains stationary, with manufacturing equipment and labour moving to and around the product, i.e. the reverse of what happens during the normal batch-production process. For the manufacture of small one-off products, the key is versatility, with general-purpose manufacturing equipment and a skilled workforce being employed to complete each unique task. After each task is completed, a new layout may be created for the next product as illustrated in figure 1.1, i.e. each work centre may be relocated within the factory to suit the product being manufactured.

86834.png

Figure 1.1: A versatile jobbing layout

Batch-Manufacturing Process Layout

The machine tools and press facilities are usually grouped according to process and used to manufacture continuously batches of products as shown in figure 1.2.

86827.png

When continuous production runs for particular products can be identified, then a more specialised layout, with groups of machines serving known product ranges, can be employed as shown for example in figure 1.3.

86820.png

Figure 1.3: Product Layout

For the layout of figure 1.3, the main advantages are

less total materials handling required

shorter total production time

simplicity of production controls

The main limitations are

less work in progress

consistent and substantial product demand required

duplication of work centres

In general manufacturing, machine tools and facilities should be optimally grouped and then optimally located in the factory. To ignore pre-grouping could reduce considerably manufacturing effectiveness.

Modern manufacturing systems

With the introduction of group technology, systems capable of dealing with the complexities of batch manufacture were introduced. By this process, using computer analysis, families or groups of similar components that can be produced together are first identified. Specialist product-oriented manufacturing cells are then introduced to the facility layout in order to obtain the benefits of grouped manufacture. Once again the main benefits of group technology are related to organisational and manufacturing considerations, e.g. reducing the required inventory levels, and not to potential layout criteria⁵.

Recently, advances in computer control of manufacturing equipment, with the development from numerical control (NC) through to direct numerical control (DNC), have led to the evolvement of flexible manufacturing systems (FMS), which are highly automated, with respect to product transport, integrated product loading and manufacture under computer supervision. The introduction of FMS raises the question of integration between the FMS and conventional layout zones as they may be incompatible with respect to operational procedures.

1.2.5 Evaluation of layouts

The following costs are associated with changes of manufacturing systems:

work-centre relocation

materials movement

potential production lost

fixed costs (see below)

site preparation

Examples of fixed manufacturing cost might include

capital cost and its annual amortisation

indirect labour costs

indirect utilities (lighting, heating, etc.)

local government taxes and building rental charges

Minimising only materials movement costs as the criterion for solving the facilities re-layout problem is unrealistic. If the best possible financial return is the main objective of an efficient layout, then the expected financial return is the function of all the layout costs. The relocation involves the design, construction, and installing of the new layout.

The design problem requires realistic layout zone and work centre physical representations. These are absent from many existing computer programs for layout for batch mode production; only limited use is made of these programs.

Installing a new layout

The transition from an existing to a new arrangement can be made

during long breaks, when no production is required

by stopping production to install the new layout in one intensive period

during downtime between production periods.

Introducing a new layout during a staff vacation eliminates disruption, but may not be the most appropriate time; a major constraint on this changeover policy may be the need to wait for the annual holiday periods.

An alternative rapid changeover approach is to halt production in order to introduce the new layout. This approach avoids the need to wait for a natural break in production, but can be very expensive because of the production losses incurred.

The third approach, as the phased changeover method, involves making a series of limited changes over an extended period during production and/or outside production time. This incurs a longer period of disruption and so delays obtaining the full benefit of the new layout. By this approach, however, production loss can be reduced and capital investment phased in over a period of time. Making changes while maintaining production requires detailed planning and, in particular, involves involving predicting the optimal non-production periods available for implementation of the relocation. It incurs several layout problems, such as

During the transition period, a series of intermediate relocations have to be implemented.

Some work centres may be displaced and need temporary storage for the affected plant.

Obsolete work centres may need to be phased out.

It may become necessary intermittently to phase in new work centres just to increase production or improve production efficiency.

1.3. Material-handling systems

1.3.1 Introduction

Materials-handling systems are usually classified according to

equipment, such as conveyors, cranes, elevators, hoists, monorails, industrial vehicles, containers, and supports as well as auxiliary equipment

material or load configurations for unit, bulk, or liquid handling.

production method, using manual, mechanised, automated and/or mass-production job shop handling-system

function, such as transportation, elevating, conveying, transferring, or self-loading systems.

1.3.2 Principles of Material Handling

The following should be considered when designing a material-handling system:

Plan all material handling and storage activities to try to obtain the maximum overall operating effectiveness.

Integrate as many handling activities as is practical into a coordinated system of operations, covering the activities concerning vendor, receipt of goods, storage, production, inspection, packaging, warehousing, shipping, transportation, and eventual customer.

Devise an operation-sequence chart and hence equipment layout in order to achieve an optimisation of material flow.

Simplify handling by reducing, eliminating, or combining unnecessary materials movements and/or equipment.

To reduce energy costs, utilise gravity to move material(s) in the desired direction wherever practical.

Strive to achieve the optimal utilisation of the available building-space.

Increase the quantity, size, or weight of unit loads or flow rate.

Mechanise handling operations as far as feasible.

Introduce automation for production, handling, and storage functions.

Consider the various aspects for handling and procedures, the materials, the required movement(s), and the methods to be used.

Standardise the handling methods chosen as well as harmonise the types and sizes of equipment used.

Use methods and equipment that are adaptable in order to be able to perform a variety of tasks, as well as be appropriate for applications where special purpose equipment is not justified.

Reduce the ratio of dead weight of the mobile handling-equipment to the weight of the load carried.

Plan for the optimal utilisation of both the handling equipment and the available manpower.

implement preventive maintenance and the optimal schedule of repairs to all the handling equipment.

Replace obsolete handling-methods and equipment provided, thereby effectiveness of operations will be improved sufficiently as justified by overall economics.

Use wiser material-handling activities to improve the control of production, inventory, and order handling.

Use handling equipment to help achieve the desired production throughput.

Determine the effectiveness of the handling performance in terms of the financial expense per unit handled.

Employ appropriate methods and equipment to ensure safe handling.

1.3.3 Equipment-Evaluation Factors

In the decision-making process to ascertain which handling system is to be chosen, the following factors should be considered:

i) Equipment characteristics

Compatibility with the rest of the handling system

Degree of complexity

Utilisation of gravity

Space requirements

Safety

Degree of mechanisation

Flexibility

Adaptability

Load/unload time

Maintenance requirements

Depreciable life and rate

Payback period for the equipment

Degree of standardisation

Durability

Quality

Operating cost

Supervision requirements

ii) Equipment utilisation

Possibility of performing other functions during movement

Optimisation of materials flow

Capability for completing the job that is undertaken

Amount of operator time required

Percentage of time the equipment will lie idle

Potential for further improvements in the equipment’s capability

Relative contribution of the equipment to production effectiveness

Influence of the equipment on quality of the end product

iii) Vendor service

Availability of equipment for purchase or hire

Manufacturer’s reputation

Availability of service for repair and maintenance of equipment

Quality of service

Availability of spare parts

iv) Economics

Leasing versus purchase

In Nigeria, cranes, conveyors, and trucks dominate the materials-handling business. Nevertheless, big companies in the petrochemical and refineries sectors as well as the National Fertiliser Company (NAFCON) and others have introduced automation, robotics, and automated guided vehicles (AGVs) into their plant. These modern computer-controlled materials-handling systems have reduced the materials-handling costs.

1.4 Materials handling during production

Usually this can be classified as occurring in one of three categories:

at the process or workplace

between machines, processes, or departments

in raw material stores and between dispatch customer and delivery.

1.4.1 At the workplace

Jobs need to be assessed continually in order to improve handling methods at the point of use of the materials. Personnel employed doing a routine mechanical job, such as feeding a machine with components could probably be much more profitably employed elsewhere, quite apart from the boring nature for the operative of this kind of work. These routine jobs should be eliminated as human activities, particularly if they are dangerous or unpleasant. Many standard devices exist to carry out such routine feeding, e.g. dial feeds, shuts, progressive feed systems, autoloaders, bowl feeders, strip and wire feeds.

Stripped of their mystique, industrial robots are little more than sophisticated handling machines, with a capacity for being programmed for different but rather similar jobs. Provided the work can be carried out to a set pattern, is repeatable, and requires no conscious creative thought by the operator, then he/she can be replaced by a robot; for instance, this applies to paint spraying as well to the removal of parts from die-casting or plastic injection moulding machines.

As robots become more developed, their control equipment increasingly includes more capable, sensory devices for touch, position, temperature, etc. As a result, their adoption to undertake more complex tasks has become more widespread.

Care is desirable to distinguish clearly uses from objectives. It now may be simple to replace a human arm with a mechanical device which exactly simulates the action desired. But, in many cases, it would be better to consider the process for which it is proposed to be used, to see why the part has to be handled at all. Redesign of the part or the process may then be possible in order to eliminate handling altogether. An example of this is the printing industry, which for centuries assembled individual type letters by hand. Later, mechanisation was introduced but the machine still assembled the type either individually or in blocks. Only with the fundamental rethinking of the printing processes, brought about by devising the offset litho process,