Eng. Nkumbwa, R. L.Copperbelt UniversitySchool of Technology

2010- Zambia

1Eng. Nkumbwa

Principles of Manufacturing Technology

What is Manufacturing Technology or Manufacturing Engineering Systems Manufacturing is the use of machines, tools and

labor to make things for use or sale. The term may refer to a range of human activity,

from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale.

2 Eng. Nkumbwa

Principles of Manufacturing Technology

Such finished goods may be used for manufacturing other, more complex products, such as:– Household appliances – Automobiles– Other products sold to wholesalers, who in turn

sell them to retailers, who then sell them to end users - the "consumers".

3 Eng. Nkumbwa

4 Eng. Nkumbwa

Understanding Manufacturing Systems Engineering

Modern manufacturing includes all intermediate processes required for the production and integration of a product's components.

Some industries, such as – semiconductor electronics

and steel manufacturers – use the term fabrication instead.

5 Eng. Nkumbwa

Understanding Manufacturing Systems Engineering

The manufacturing sector is closely connected with engineering and industrial design or industrial engineering.

Examples of major manufacturers include:– North America include:

General Motors Corporation,  General Electric, Pfizer. Examples in Europe include :

– Volkswagen Group, – Siemens, and Michelin. – Examples in Asia include 

Toyota, Samsung, and Bridgestone. Example in Zambia include: ZamSugar, ZamBrew, Lafarge, Zambezi, Trade kings, Uniliver, TAP,

Kafue Steel, Amanita, Zambeef, Parmalat, Milling Co., Plastic Co. , Indeni, Scaw, etc6 Eng. Nkumbwa

7 Eng. Nkumbwa

8 Eng. Nkumbwa

9 Eng. Nkumbwa

Economics of Manufacturing

According to some economists,

manufacturing is a wealth-producing sector of an economy,

whereas a service sector tends to be wealth-consuming.

10 Eng. Nkumbwa

Economics of Manufacturing

Manufacturing is a huge component of the modern economy.

Everything from knitting to oil extraction to steel production falls under the description of manufacturing.

The concept of manufacturing rests upon the idea of transforming raw materials, either organic or inorganic, into products that are usable by society.

11 Eng. Nkumbwa

Manufacturing Categories

Chemical industry– Pharmaceutical

Construction Electronics

– Semiconductor Engineering

– Biotechnology– Emerging technologies– Nanotechnology– Synthetic biology, Bioengineering

Energy industry Food and Beverage

– Agribusiness– Brewing industry– Food processing

12 Eng. Nkumbwa

Manufacturing Categories

Industrial design– Interchangeable parts

Metalworking– Smith– Machinist– Machine tools– Cutting tools (metalworking)– Free machining– Tool and die maker– Global steel industry trends– Steel production

Metalcasting

13 Eng. Nkumbwa

Manufacturing Categories

Plastics Telecommunications Textile manufacturing

– Clothing industry– Sailmaker– Tentmaking

Transportation– Aerospace manufacturing– Automotive industry– Bus manufacturing– Tire manufacturing– LETS JUST SAY ANYTHING THAT IS NOT NATURAL

IS MANUFACTURING14 Eng. Nkumbwa

So, What is Manufacturing?

According to Webster's, Manufacturing is the making of goods or

wares by manual labor or by machinery, especially on a large scale, from raw materials or unfinished materials.

It is the making of a finished product or goods.

15 Eng. Nkumbwa

Manufacturing Methods

There are different manufacturing methods namely:– Batch Production– Job Production– Continuous Production

16 Eng. Nkumbwa

Batch Production

Batch production is the manufacturing technique of creating a group of components at a workstation before moving the group to the next step in production.

Batch production is common in bakeries and in the manufacture of sports shoes, pharmaceutical ingredients (APIs), inks, paints and adhesives.

In the manufacture of inks and paints, a technique called a colour-run is used.

17 Eng. Nkumbwa

Batch Production

A colour-run is where one manufactures the lightest colour first, such as light yellow followed by the next increasingly darker colour such as orange, then red and so on until reaching black and then starts over again.

This minimizes the cleanup and reconfiguring of the machinery between each batch.

18 Eng. Nkumbwa

Job Production

Job production, sometimes called jobbing, involves producing a one-off product for a specific customer.

Job production is most often associated with small firms (making railings for a specific house, building/repairing a computer for a specific customer, making flower arrangements for a specific wedding etc.) but large firms use job production too.

19 Eng. Nkumbwa

Continuous Production

Continuous production is a method used to manufacture, produce, or process materials without interruption.

This process is followed in most oil and gas industries and petrochemical plant and in other industries such as the float glass industry, where glass of different thickness is processed in a continuous manner.

Once the molten glass flows out of the furnace, machines work on the glass from either side and either compress or expand it.

Controlling the speed of rotation of those machines and varying them in numbers produces a glass ribbon of varying width and thickness.20 Eng. Nkumbwa

Cell Production

Cell production involves both machines and human workers. In conventional production, products were manufactured in

separate areas (each with a responsibility for a different part of the manufacturing process) and many workers would work on their own, as on a production line.

In cell production, or cellular manufacturing workers are organized into multi-skilled teams.

Each team is responsible for a particular part of the production process including quality control and health and safety.

Each work cell is made up of one team who deliver finished items on to the next cell in the production process.

21 Eng. Nkumbwa

Mass Production

Mass production (also called flow production, repetitive flow production, series production, or serial production) is the production of large amounts of standardized products, including and especially on assembly lines. i.e. Elsweedy in Ndola.

The concepts of mass production are applied to various kinds of products, from fluids and particulates handled in bulk (such as food, fuel, chemicals, and mined minerals) to discrete solid parts (such as fasteners) to assemblies of such parts (such as household appliances and automobiles).

22 Eng. Nkumbwa

23 Eng. Nkumbwa

Lean Production

Lean Production, which is often known simply as "Lean", is a production practice that considers the expenditure of resources for any goal other than the creation of value for the end customer to be wasteful, and thus a target for elimination.

Working from the perspective of the customer who consumes a product or service, "value" is defined as any action or process that a customer would be willing to pay for.

Basically, lean is centered around preserving value with less work. Lean manufacturing is a generic process management philosophy

derived mostly from the Toyota Production System (TPS) (hence the term Toyotism is also prevalent) and identified as "Lean" only in the 1990s.

It is renowned for its focus on reduction of the original Toyota seven wastes to improve overall customer value, but there are varying perspectives on how this is best achieved.

24 Eng. Nkumbwa

Agile Production

For the past ten years a quality revolution has arose because now, the marketplace has become global.

A sophisticated and aware customer base has grown because of the increase of service industries where the customer plays a direct role in the delivery process.

No longer can companies assume they can put out products to customers at the manufacturers schedule and quality levels. 

Many companies have realized this. Many have researched for was to make positive changes, which will permit them to identify, and quickly respond to the customer likes and complaints.

At the same time, these changes must allow the manufacture the ability to get their products quickly to market.

25 Eng. Nkumbwa

Agile Production

This is known as Agile Manufacturing. Agility means to have the ability to change quickly. The development of manufacturing support technology,

which permits marketers, designers, and production personnel the ability to share a common database of parts and products, is one contributing factor a manufacturer must have in order to become an agile manufacturer. Goldman et al. (1995) suggest that Agility has four underlying components: deliver value to the customer; be ready for change; value human knowledge and skills; form virtual partnerships. 

26 Eng. Nkumbwa

Industrial Engineering

Industrial engineering is a branch of engineering concerned with the development, improvement, implementation and evaluation of integrated systems of people, money, knowledge, information, equipment, energy, material and process.

It also deals with designing new prototypes to help save money and make the prototype better.

Industrial engineering draws upon the principles and methods of engineering analysis and synthesis, as well as mathematical, physical and social sciences together with the principles and methods of engineering analysis and design to specify, predict, and evaluate the results to be obtained from such systems.

27 Eng. Nkumbwa

Understanding Product Design

For any organization to deliver the required service or product to the market, they must first understand the customer requirements and design the product that meets the stated and implied needs.

All things on this plant that are not natural where once designed and manufactured.

Below is an illustration of the design process.

28 Eng. Nkumbwa

Recognition of Need

Presentation

Evaluation

Analysis & Optimisation

Problem Synthesis

Definition of Problem or Need

29 Eng. Nkumbwa

Waterfall Product Development

30 Eng. Nkumbwa

Use of Concurrent Engineering

After identifying the requirements for the New Product, a design will be developed for the required product.

However, just having the details of the design alone is not enough to deliver the product to the consumer, so we need Manufacturing information which will suggest the processes required to make the product.

Therefore, Product Design and Product Manufacturing Process should be done at the same time or in parallel.

Concurrent Engineering is a work methodology based on the parallelization of tasks (ie. performing tasks concurrently).

It refers to an approach used in product development in which functions of design engineering, manufacturing engineering and other functions are integrated to reduce the elapsed time required to bring a new product to the market.

31 Eng. Nkumbwa

New Product Analysis

Everyday we use thousands of different products, from telephones to bikes and drinks cans to washing machines and microwaves.

But have you ever thought about how they work or the way they are made?

Every product is designed in a particular way - product analysis enables us to understand the important materials, processing, economic and aesthetic decisions which are required before any product can be manufactured.

An understanding of these decisions can help us in designing and making for ourselves.

32 Eng. Nkumbwa

Getting Started

The first task in product analysis is to become familiar with the product! What does it do? How does it do it? What does it look like?

All these questions, and more, need to be asked before a product can be analysed.

As well as considering the obvious mechanical (and possibly electrical) requirements, it is also important to consider the ergonomics, how the design has been made user-friendly and anymarketing issues - these all have an impact on the later design decisions.

33 Eng. Nkumbwa

Let's take the example of a bike

What is the function of a bicycle? How does the function depend on the type of

bike (e.g. racing, or about-town, or child's bike)? How is it made to be easily maintained? What should it cost? What should it look like (colours etc.)? How has it been made comfortable to ride? How do the mechanical bits work and interact?

34 Eng. Nkumbwa

Systems and Components

There are 2 main types of product - those that only have one component (e.g. a spatula) and those that have lots of components (e.g. a bike). Products with lots of components we call systems. For example:

35 Eng. Nkumbwa

System Components

Product Components

Bike Frame, wheels, pedals, forks, etc.

Drill Case, chuck, drill bit, motor, etc.

Multi-gymSeat, weights, frame, wire,

handles, etc.

36 Eng. Nkumbwa

Product Analysis

In product analysis, we start by considering the whole system. But, to understand why various materials and processes are used, we usually need to 'pull it apart' and think about each component as well.

We can now analyse the function in more detail and draft a design specification.

37 Eng. Nkumbwa

Some important design questions

To build a design specification, consider questions like the following:– What are the requirements on each part (electrical,

mechanical, aesthetic, ergonomic, etc)?– What is the function of each component, and how do

they work?– What is each part made of and why?– How many of each part are going to be made?– What manufacturing methods were used to make

each part and why ?– Are there alternative materials or designs in use and

can you propose improvements?38 Eng. Nkumbwa

Design Questions

These are only general questions, to act as a guide - you will need to think of the appropriate questions for the products and components you have to analyse. For a drinks container, a design specification would look something like:

– provide a leak free environment for storing liquid– comply with food standards and protect the liquid from health hazards– for fizzy drinks, withstand internal pressurisation and prevent escape

of bubbles– provide an aesthetically pleasing view or image of the product– if possible create a brand identity– be easy to open– be easy to store and transport– be cheap to produce for volumes of 10,000+

39 Eng. Nkumbwa

Choosing the Right Materials

Given the specification of the requirements on each part, we can identify the material properties which will be important - for example:

40 Eng. Nkumbwa

Choosing the Right Materials

Requirement Material Property

must conduct electricity electrical conductivity

must support loads without breaking strength

cannot be too expensive cost per kg

41 Eng. Nkumbwa

Material Selection

One way of selecting the best materials would be to look up values for the important properties in tables. But this is time-consuming, and a designer may miss materials which they simply forgot to consider.

A better way is to plot 2 material properties on a graph, so that no materials are overlooked - this kind of graph is called a materials selection chart (these are covered in another part of the tutorial).

Once the materials have been chosen, the next step is normally to think about the processing options.

42 Eng. Nkumbwa

Choosing the Right Process

It is all very well to choose the perfect material, but somehow we have to make something out of it as well! An important part of understanding a product is to consider how it was made - in other words what manufacturing processes were used and why.

There are 2 important stages to selecting a suitable process:– Technical performance: can we make this product with the

material and can we make it well?– Economics: if we can make it, can we make it cheaply

enough? Process selection can be quite an involved problem - we deal

with one way of approaching it in another part of the tutorial. So, now we know why the product is designed a particular way,

why particular materials are used and why the particular manufacturing processes have been chosen.

Is there anything else to know?43 Eng. Nkumbwa

Wrap Up…

Product analysis can seem to follow a fixed pattern:– Think about the design from an ergonomic and

functional viewpoint.– Decide on the materials to fulfil the performance

requirements.– Choose a suitable process that is also economic.

Whilst this approach will often work, design is really holistic - everything matters at once - so be careful to always think of the 'bigger picture'. 44 Eng. Nkumbwa

Example Analysis

Is the product performance driven or cost driven? This makes a big difference when we choose materials. In a performance product, like a tennis racquet, cost is one of

the last factors that needs to be considered. In a non-performance product, like a drinks bottle, cost is of

primary importance - most materials will provide sufficient performance (e.g. although polymers aren't strong, they are strong enough).

Although we usually choose the material first, sometimes it is the shape (and hence process) which is more limiting.

With window frames, for example, we need long thin shaped sections - only extrusion will do and so only soft metals or polymers can be used (or wood as it grows like that!).

45 Eng. Nkumbwa

Choosing between Different Materials

There are three main things to think about when choosing materials (in order of importance):– Will they meet the performance requirements?– Will they be easy to process?– Do they have the right 'aesthetic' properties?

We deal with the processing aspects of materials in a different part of this course.

For now it is sufficient to note that experienced designers aim to make the decisions for materials and processes separately together to get the best out of selection.

The choice of materials for only aesthetic reasons is not that common, but it can be important: e.g. for artists.

However, the kind of information needed is difficult to obtain and we won't deal with this issue further here.46 Eng. Nkumbwa

Material Selection

Most products need to satisfy some performance targets, which we determine by considering the design specification e.g. they must be cheap, or stiff, or strong, or light, or perhaps all of these things...

Each of these performance requirements will influence which materials we should choose - if our product needs to be light we wouldn't choose lead and if it was to be stiff we wouldn't choose rubber!

So what approach do we use to select materials?

47 Eng. Nkumbwa

Using Material Selection Charts

So what we need is data for lots of material properties and for lots of materials.

This information normally comes as tables of data and it can be a time-consuming process to sort through them.

And what if we have 2 requirements - e.g. our material must be light and stiff - how can we trade-off these 2 needs?

The answer to both these problems is to use material selection charts.

Here is a materials selection chart for 2 common properties: Young's modulus (which describes how stiff a material is) and density.

48 Eng. Nkumbwa

49 Eng. Nkumbwa

Using Material Selection Charts

On these charts, materials of each class (e.g. metals, polymers) form 'clusters' or 'bubbles' that are marked by the shaded regions.

We can see immediately that:– metals are the heaviest materials,– foams are the lightest materials,– ceramics are the stiffest materials.

But we could have found that out from tables given a bit of time, although by covering many materials at a glance, competing materials can be quickly identified.

Where selection charts are really useful is in showing the trade-off between 2 properties, because the charts plot combinations of properties.

For instance if we want a light and stiff material we need to choose materials near the top left corner of the chart - so composites look good.

Note that the chart has logarithmic scales - each division is a multiple of 10; material properties often cover such huge ranges that log scales are essential.

50 Eng. Nkumbwa

Using Material Selection Charts

To find the best materials we need to use the Young's modulus - density chart from amongst the available charts. The charts can be annotated to help reveal the 'best' materials, by placing a suitable selection box to show only stiff and light materials.

What can we conclude? The values of Young's modulus for polymers are low, so

most polymers are unlikely to be useful for stiffness-limited designs. 

Cambridge Engineering Selector (CES) is the Software used for Material Selection developed by Prof. Ashby.

Other material property selection charts include:

51 Eng. Nkumbwa

52 Eng. Nkumbwa

53 Eng. Nkumbwa

54 Eng. Nkumbwa

55 Eng. Nkumbwa

56 Eng. Nkumbwa

57 Eng. Nkumbwa

Wrap Up

By considering 2 (or more) charts, the properties needed to satisfy the main design requirements can be quickly assessed.

The charts can be used to identify the best classes of materials, and then to look in more detail within these classes.

There are many other factors still to be considered, particularly manufacturing methods. The selection made from the charts should be left quite broad to keep enough options open.

A good way to approach the problem is to use the charts to eliminate materials which will definitely not be good enough, rather than to try and identify the single best material too soon in the design process.

58 Eng. Nkumbwa

How is a processing route chosen?

The selection of a suitable process to manufacture a component is not a straightforward matter.

There are many factors which need to be considered, for example: size of component, material to be processed and tolerance on dimensions.

Whilst all processes have slightly different capabilities, there is also a large overlap - for many components there are a large number of processes which would do the job okay. So, where do we start?

59 Eng. Nkumbwa

Material Compatibility

In product analysis (and a lot of design work), the material to be processed is often known before the process to be used has been decided.

This makes life a little easier as the first thing we can do now is check what processes can be used for our chosen material - i.e. which are compatible.

For convenience, processes can be split up into:– Metal shaping: e.g. forging, rolling, casting– Polymer shaping: e.g. blow moulding, vacuum forming– Composite forming: e.g. hand lay-up– Ceramic processing: e.g. sintering– Machining: e.g. grinding, drilling– Joining: e.g. soldering, gluing, welding

60 Eng. Nkumbwa

Material-Process Compatibility Table

We can then use a material-process compatibility table to determine which processes are suitable for manufacture.

61 Eng. Nkumbwa

+ : routine? : difficult

X : unsuitable

Polymer Wood

ABS(thermoplastic)

UF(thermoset)

Pine

PolymerShaping

Polymer extrusion

+ X  

Compression moulding

+ +  

Injection moulding

+ ?  

Blow moulding + X  

Machining

Milling + X +Grinding X X +Drilling + ? +Cutting + ? +

Joining

Fasteners + + +Solder / braze X X XWelding + X XAdhesives + + +

62 Eng. Nkumbwa

Process Compatibility Table

These tables show whether a particular material-process combination is routine, difficult or unsuitable.

Using this table we can usually narrow down our choice of processing options, but how can we go further?

63 Eng. Nkumbwa

Comparing the costs of processing routes

There are many costs involved in the making and selling of a product, these include:

– Research– Advertising– Packaging– Distribution– Manufacturing

For different products, the importance of each contribution will vary. Note that the cost is not the same as the price - the difference is the

manufacturer's profit! Here we are only interested in the manufacturing cost - the other costs

are not likely to be affected much by our choice of process.

64 Eng. Nkumbwa

Manufacturing Costs

So how can we go about estimating how much it might cost to make a product?

The easiest way is to notice that the basic manufacturing cost has 3 main elements:– Material Costs– Start-Up Cost– Running Cost

65 Eng. Nkumbwa

Material cost

The material cost per component depends on the size of the component.

We may assume that (for a given component) the same amount of material is used for all processes:– Material cost per part = constant

(same value for all processes)

66 Eng. Nkumbwa

Manufacturing Costs=Constant

67 Eng. Nkumbwa

Startup cost

All new products have one-off startup costs, such as special tools or moulds which have to be made.

This cost only occurs once, so it is shared between all the total number of components made - the 'batch size':– Startup cost per part = one-off cost ÷ batch size

(gets less for bigger batches and is different for each process)

68 Eng. Nkumbwa

Start-Up Cost

69 Eng. Nkumbwa

Running cost

Many manufacturing costs will be charged at an hourly rate, such as energy and manpower.

In addition the capital cost of the machine must be "written off" over several years, which can also be regarded as an hourly cost - the same would apply if instead a machine was rented.

The share of this hourly running cost per part depends on how many parts are made per hour, the production rate:

– Running cost per part = hourly cost ÷ production rate(constant, but different for each process)

70 Eng. Nkumbwa

Running Costs

71 Eng. Nkumbwa

Total Manufacturing Cost

The total cost is the sum of these 3 cost elements.

These are;– Material Costs– Start-Up Costs– Running Costs

72 Eng. Nkumbwa

73 Eng. Nkumbwa

Case Example: Aero Engine

74 Eng. Nkumbwa

Aero-Engine Analysis

Hotter, Stiffer, Stronger, Lighter… Where does the aero-engine go next? Use the chart below to help you select the

appropriate material for each component of the Jet Engine.

75 Eng. Nkumbwa

76 Eng. Nkumbwa

Sustainable Design or Eco-Design and Eco-Manufacturing or Green Mfg.

Sustainable design (also called environmental design, environmentally sustainable design, environmentally-conscious design, green design etc) is the philosophy of designing physical objects, the built environment and services to comply with the principles of economic, social, and ecological sustainability.

The intention of sustainable design is to "eliminate negative environmental impact completely through skillful, sensitive design“.

Manifestations of sustainable designs require no non-renewable resources, impact on the environment minimally, and relate people with the natural environment.77 Eng. Nkumbwa

Design for Environment (DfE)

Design for Environment (DfE) is a general concept that refers to a variety of design approaches that attempt to reduce the overall environmental impact of a product, process or service, where environmental impacts are considered across its life cycle.

There are three main concepts that fall under the Design for Environment umbrella:

– Design for environmental processing and manufacturing: This ensures that raw material [Resource extraction|extraction] (mining, drilling, etc.), processing (processing reusable materials, metal melting, etc.), manufacturing are done using materials and processes which are not dangerous to the environment or the employees working on said processes. This includes the minimization of waste and hazardous by-products, air pollution, energy expenditure, among others.

78 Eng. Nkumbwa

Design for Environment (DfE)

– Design for environmental packaging: This ensures that the materials used in packaging are environmentally friendly, which can be achieved through the reuse of shipping products, elimination of unnecessary paper and packaging products, efficient use of materials and space, use of [Recycling|recycled] and/or recycleable materials.

– Design for disposal or reuse: The [End-of-life (product)|end-of-life] of a product is very important, because some products emit dangerous chemicals into the air, ground and water after they are disposed of in a landfill.

– Planning for the reuse or refurbishing of a product will change the types of materials that would be used, how they could later be disassembled and reused, and the environmental impacts such materials have.

Definition: – Design For Environment (DFE) is the idea of implementing certain aspects of

environmentally friendly design to create a sustainable product . Although there is no actual DFE certification, following the Design For Environment guidelines helps to minimize waste and pollution, and saves money that is typically spent on product reprocessing.

79 Eng. Nkumbwa

Global Competitiveness

Competitiveness is a comparative concept of the ability and performance of a firm, sub-sector or country to sell and supply goods and/or services in a global market.

Although widely used in economics and business management, the usefulness of the concept, particularly in the context of Manufacturing Systems is critical.

The term may also be applied to markets, where it is used to refer to the extent to which the market structure may be regarded as perfectly competitive.

This usage has nothing to do with the extent to which individual firms are "competitive'.

Read more about Manufacturing Competitiveness in Zambia80 Eng. Nkumbwa

Wrap Up

Any worries this far??

81 Eng. Nkumbwa