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MODULE TITLE : ENGINEERING DESIGN

TOPIC TITLE : DESIGN SPECIFICATION

LESSON 1 : DESIGN AND DESIGN PROCESS

EDE - 1 - 1

Published by Teesside University Open Learning (Engineering)

School of Science & Engineering

Teesside University

Tees Valley, UK

TS1 3BA

+44 (0)1642 342740

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INTRODUCTION ________________________________________________________________________________________

This module intends to show students how to carry out a design project, which

is a core module within the HNC programmes. We will look at three aspects:

• preparation of design specification – customer requirements, design

parameters and design information

• production of design report – analysis of possible design solutions,

evaluation, compliance check and report

• use of computer-based technology – key features of a computer-aided

design system and software.

The first two topics are essential for all engineering students, whereas the

computer-based technology required could be different for students in various

areas, e.g. mechanical engineering students intensively use CAD (computer

aided design) to do engineering drawing, analysis and simulation, and software

such as AutoCAD, PreEngineer and Solid Works would be necessary;

electronic and electric or instrumentation students are probably required to use

CAD to design and analyse PCB (printed circuit board) layouts, for which

there are a number of pieces of software available, such as PROTEL, ORCAD,

Electronic Workbench and P-CAD 2000. Anyway, every engineering student

is expected to demonstrate an ability to use appropriate computer-based tools

as part of the engineering design process.

We hope this module will enable students to learn the nature of design, the

central activity of engineering, and help them to learn the tools and techniques

of formal design that will be useful in framing the design problems they will

face during their education and their careers.

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________________________________________________________________________________________

YOUR AIMS ________________________________________________________________________________________

After studying this lesson, you should be able to:

• write a suitable design brief

• describe the processes involved in design

• understand the need for uncertainty in the early stages of design.

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STUDY ADVICE ________________________________________________________________________________________

A CAD program has to be used in order to do this module. In the lessons on

CAD within this module, it is assumed that you will be using MicroStation.

This program has been chosen because it is reasonably priced, yet offers

features that are normally only found in much more expensive software.

You may prefer to use a program that you have at home or have access to at

your place of work. While that is perfectly acceptable, you must be prepared

to supply drawings on disc in MicroStation compatible format with your

assignments.

Further, you cannot expect technical support from TUOL(E) for programs

other than MicroStation.

Although most of the examples have a mechanical bias, the principles apply to

all disciplines.

The Tutor Marked Assignments for this module will follow a theme and will

link together to form a simple design project, which is a requirement of the

module.

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________________________________________________________________________________________

ENGINEERING DESIGN ________________________________________________________________________________________

DESIGN

We can use the word design as either a noun or a verb. We can refer to a

design, or the need to design something. The authors of BS 7000: (1989)

Guide to Managing Product Design decided that the following definitions

applied:

To Design

“To generate information from which a required product can become reality.”

A Design

“The set of instructions (e.g. specifications, drawings and schedules) necessary

to construct a product.”

[Note: this British Standard has now been superseded by later versions, but the

content has remained essentially the same.]

Design is the series of activities by which the information known and recorded

about a designed object is added to, refined, modified, or made more or less

certain. Thus, design is the process of originating systems and predicting their

performance, which changes the state of information that exists about a

designed object. In the design process, the detailed information about the

designed object increases and becomes less abstract.

Design is a creative process and is motivated by clients. A design problem is

created when there is a desire for a change in the state of information about a

designed object. A design solution is an abstraction of an artifact, providing a

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description of this artifact. There are technology and tools, which mainly form

the subjects of this module, we can use to support our creativity and to help us

make better decisions in the design process.

DEFINING ENGINEERING DESIGN

Engineering design is the systematic, intelligent generation and evaluation of

specifications for artifacts, such that the form and function of an artefact attain

stated objectives with desired specifications.

The form of an artifact is its shape or geometry. The function means what the

artifact is supposed to perform. The design specifications are the precise

descriptions of the properties of the object being designed, which include a

series of statements, clearly numbered, of the characteristics (such as quantity,

shape, material, location, performance, etc.) of a structure, apparatus,

machine, system or process, written in terms that can be measured. Therefore,

the specifications are a means of communicating the needs and intentions of

one party to another, and an interface between two stages of a project.

THE NATURE OF DESIGN

The nature of the desired state is often difficult to specify. Many different

models of design are based on the three stage approach: analysis, synthesis,

and evaluation. Analysis defines the problem and the explicit goals.

Synthesis tries to find plausible solutions for the defined problem. Evaluation

selects alternative solutions in respect to the original goals. Generation-and-

test cycles are used to search the problem space. In these models design can

thus be seen as a problem-solving process exploring different possible states,

where states represent design solutions.

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DESIGN METHOD

Design method is a broad area that focuses on:

• exploring possibilities and constraints by focusing critical thinking skills

on to research and defining problem spaces for existing products or

services – or the creation of new categories

• redefining the specifications of design solutions, which can lead to better

guidelines for traditional design activities (graphic, industrial,

architectural, etc.)

• managing the process of exploring, defining, creating artifacts continually

over time

• prototyping possible scenarios, or solutions, that incrementally or

significantly improve the inherited situation.

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________________________________________________________________________________________

DESIGN PROCESS ________________________________________________________________________________________

BS 7000 (1989) suggests an ‘idealized product evolution’ which contains a

number of stages. You should take special note of the stages involved, as we

will be expecting you to follow them when you do your own design studies

later in the course.

Product development tends not to follow such a simple model, however, as

findings late in the process often necessitate a return to an early stage. Design

is, by its nature, an iterative process.

The idealized product evolution has the following stages:

MOTIVATION OR NEED STAGE

Firstly, an idea is triggered for a new product by customer requirements.

Take a few moments to consider what the sources of inspiration for a new product, or

modification to an existing product, might be. Write down your ideas below:

...................................................................................................................................................

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There are many possible triggers for a new or modified design, some are listed

below:

• a customer might request an additional set of features to an existing

product

• a customer might have a job to be done which requires a new product, e.g.

supermarket sales outlets require a machine to read bar codes on products

• a sales person might see that the competition is offering enhanced

features, e.g. a manufacturer of trucks is made aware that the competitor's

product has a more powerful engine

• an inventor might knock on the door, e.g. see Flymo example below

• it might be possible to exploit some new scientific research, e.g. here is a

thing called a laser, what can it be used for?

• a comprehensive market study might define a product requirement

• the company might carry out an analysis of its products and processes and

decide to enter a new market, to make better use of an existing

manufacturing facility, e.g. several ship yards moved from building ships

to oil rigs.

You have probably seen the highly successful Flymo Garden Vac. That idea

was introduced to the company by an external inventor. He, legend has it, was

introduced to the managing director and then proceeded to spread a sackful of

assorted debris over the boardroom floor, before using his prototype vac to

clear it all up.

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Following the initial stimulus, a project proposal is prepared which lays out a

first estimate of the objectives of the product, and provides a budget for the

development of it.

There then follows a feasibility study to allow senior management to decide

whether or not to proceed with the project. This would normally involve some

market research and perhaps some preliminary engineering and financial

calculations.

THE DESIGN BRIEF

If it is decided to proceed with the project then a design brief should be

prepared. This design brief should provide enough information to enable the

design team to produce a design from which a product can be manufactured. It

should contain all constraints on and requirements of the design. The

designers should not be restricted by too prescriptive a brief, however, the brief

should state what is required of the product, not how that should be achieved.

What items do you feel should normally appear in a design brief? Write them down

below:

...................................................................................................................................................

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BS 7000: (1989) Managing Product Design, considers that the brief should

cover three areas:

• performance

• cost

• timescale.

Quality function deployment, the subject of the next lesson, might be used to

finalise the brief.

Performance requirements might include:

– appearance and texture

– size, mass, e.g. it must fit within a standard container

– dynamic requirements, e.g. power output, speed, acceleration

– ease of use, the target customer might be defined

– environmental conditions of use, e.g. temperature, corrosive conditions

– safety

– relevant standards and legislation

– reliability, e.g. how many operating hours between breakdowns?

– maintainability, e.g. can the user change the batteries or is it discarded?

– disposability, are the plastic parts recyclable?

Cost requirements might include:

– manufacturing costs

– warranty costs

– maintenance costs

– design costs

– other costs.

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Timescale requirements might include:

– quantity to be made

– launch date

– anticipated shelf life

– expected sales life of product

– anticipated product life.

Note that the design brief does not in any way constitute a finished design, it

should not unnecessarily inhibit the design team in their search for a solution

to the problem.

You have been commissioned to write a design brief for a domestic toaster for use in

the UK. What would you write against each of the three headings below:

(1) Performance Requirements

.........................................................................................................................................

(2) Cost Requirements

.........................................................................................................................................

(3) Timescale Requirements

.........................................................................................................................................

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Your answer might look a bit like this:

(1) Performance Requirements

smooth external finish, easily cleaned

white in colour

maximum footprint 350 × 150 mm toast bread ranging from 8 to 16 mm thickness, maximum 250 × 200 mm overall size

2 slice capacity

toasting time not more than 2 minutes

infinitely variable cooking setting

use mains electricity at 240 V ac 50 Hz

operable with one hand

for use in a domestic kitchen environment

comply with necessary BS for domestic appliances

expected service life, not less than 5 years

no user maintainable parts

all parts to be recyclable.

(2) Cost Requirements

manufactured cost per item not more than £5

tooling costs, maximum £300,000

warranty costs not to exceed 0.1% of sales income

design budget £80,000

(3) Timescale Requirements

75,000 required per year for four years

product launch date 2nd March 2007.

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Notice that the brief does not tell the designer how to design the toaster, merely

what the perceived market needs are, and the amount of time and money the

company are prepared to put into the project. The problems of toasting the

bread remain to be solved.

The design brief is the formal outcome of the motivation or need stage of the

design process.

PRODUCT DESIGN SPECIFICATION (PDS)

From Wikipedia, The Free Encyclopedia, the description of design

specification is:

Design specifications are the measurements and characteristics of a structure

or object which provide for a workable, sustainable, or pleasing creation or

construct. This can apply to a wide variety of manufactured or fabricated

objects, such as buildings, automobiles, and clothes and also utility,

computing, and distribution systems. Any functional thing made by human

beings has certain specific details.

BS 7373: (2001) Guide to the preparation of specifications gives guidance on

the layout and preparation of specifications, and describes systems for their

management. It applies to specifications used within industry, commerce and

the public sector.

The purpose of the PDS is to ensure that your design actually addresses your

customer needs. This is essential if your product is to succeed. The PDS

comprises your quantitative statement of what you want to design prior to

starting to design it. In other words, the PDS should be largely independent of

any specific embodiment of your product, so multiple solution concepts are

possible.

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It is important that before you produce a ‘solution’ there is a true

understanding of the actual problem. The PDS is a document listing the

problem in detail. To obtain that, designers must work with the customer and

analyse the marketplace to produce a list of requirements necessary to produce

a successful product. During the design process, the designers should

constantly refer back to this document to ensure designs are appropriate.

To produce the PDS it is likely that you will have to research the problem and

analyse competing products and all important points and discoveries should be

included in your PDS.

A PDS can split a problem into smaller categories to make it easier to consider.

The final document should fully cover as clearly as possible all the

requirements that a product must fulfil, together with any constraints that may

affect the product. The actual or intended customer should be consulted as

fully as possible while the PDS is being drawn up as their requirements are of

paramount importance. Any numeric properties in the PDS should be

specified as exactly as possible, together with any tolerances allowed on their

values.

In a product design process, you begin by defining your customer

requirements, which are stated in the language of the customer. Your team

then converts those needs to engineering specifications.

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DESIGN STAGE

Armed with the product brief the designers can get to work. This constitutes

the design element of the product development process and it comprises

several stages.

Concept Design

The first stage is a free thinking stage where many possible solutions are

generated and considered.

The concept design stage is relatively cheap to carry out. A small product

development team will be employed to generate and review ideas. Although

there will be a wage bill, it will not be large. There are initially no hardware

costs to consider, whereas when the design becomes more advanced, there will

be more people involved and manufacturing tooling to buy.

The detailed product specification is very uncertain at this stage, only the

design brief exists to guide the team. There could be a range of possible

design solutions, all technically acceptable.

It is vital that the team are given sufficient time to carry out this part of the

work.

If stones are left unturned during the concept stage then the consequences

might be extremely expensive, if not catastrophic, later.

Let us consider a rather silly example, that hopefully you will not forget.

Consider two rival companies designing personal stereo systems (in the days

before there were personal stereo systems).

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Company A has heard that company B is about to launch a new product and

some details have leaked out. Company A tells the design team that they must

have a product ready within a very short timescale, and constantly berates the

designers for not getting a move on. "Where are the manufacturing drawings,

you lazy hounds...," shouts the managing director (MD).

Company B takes a more considered approach and allows their designers

plenty of thinking time.

The hard pressed design manager at company A looks desperately around for a

way of getting music to the ears of a pedestrian. The first idea he thinks up is a

pair of good quality loudspeakers mounted on a bracket slung around the user's

neck. Relieved to be able to report to the MD that a solution is in hand, work

begins on this idea in earnest. Thousands are spent on developing a

comfortable neck bracket to carry the two speakers.

The rival product appears on the street with 'in the ear' phones. Company A

goes bankrupt.

It is impossible to stress too heavily the importance of the concept stage. It is

quite possible to produce a perfectly engineered solution that is easy and cheap

to make, but if the concept is wrong it will never sell. The Sinclair C5 is an

example of this. Engineers tend to delight in technical details, but they

sometimes fail to see the wood for the trees.

In the EITB (Engineering Industrial Training Board) training pack on design

methods, the best part of a chapter is devoted to the subject of uncertainty in

design. A vague design brief is regarded as having a high degree of

uncertainty, but as the design proceeds the product definition becomes clearer,

the uncertainty diminishes. Designers should be encouraged to spend time in

the region of maximum uncertainty, to question the design brief, expand upon

the uncertainty and look at all possibilities. If necessary go back to the

customer and ask if a particular restraint really is necessary, “what if we....?”

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A fundamental rule is that it is better to investigate a number of design

solutions rather than run with the first idea that comes to mind.

This approach is valid at all stages of the design process, it certainly applies to

the overall concept of the solution, but is also relevant when each smaller

problem is to be solved. For example, it has been decided to build a snow

mobile with caterpillar tracks; what about the design of the tracks, how should

the power be transmitted from engine to the tracks, etc?

Later lessons cover the techniques that can be used to generate a range of

possible design solutions. One technique that you are probably familiar with is

that of brainstorming, where people are invited to write down a variety of

ways of solving a problem. While brainstorming is by its very nature an

informal process, there are nevertheless rules that can be applied to produce

the best results. Any ideas are acceptable, there should be no criticism to

prevent the free flow of thought. What is required is a large number of

different ideas. Brainstorming, like several other design techniques, is best

carried out as a group activity where the team members feed off the ideas of

others.

Concept Selection

Having developed a range of possible solutions, the next task is to select the

most suitable one, i.e. that which satisfies the design brief most perfectly. This

is often a difficult task, particularly if a team is involved, as individuals tend to

favour their own ideas. What is required is a set of criteria against which the

different designs can be compared. There is a technique for doing this called a

weighted objective analysis, and this will be covered in a later lesson.

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Embodiment Design

Having selected the most suitable concept, the next stage in the design process

is to begin to put flesh on the bones of the idea. This will normally involve a

combination of drawing and calculation. The concept design is accurately

drawn out as a layout or scheme drawing. The key dimensions may be fixed in

a variety of ways:

• by the design brief, e.g. in the case of our toaster, the footprint was

specified

• by calculation

• by reference to standards or specifications with which the design has to

comply

• by the need to use existing parts or manufacturing equipment

• even today the designer occasionally has to just draw a component so that

it looks right, in scale with the other parts

• if the product is a consumer durable, then styling must be considered.

Take the designer of an engine. The design brief has fixed the bore, stroke and

speed of the engine, but now the crankcase, connecting rods and crankshaft

have to be drawn. If the engine is a marine engine then the crankshaft may

have to comply with the requirements of the classification societies, e.g.

Lloyds.

Thus, the minimum diameter of the crankpin is fixed. It is advantageous if the

main body of the connecting rod can be lifted through the bore of the cylinder,

another restraint.

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The designer is aware that the connecting rod should be as light as possible,

because the forces in an engine are related to the mass of the components. It is

easy to calculate the force on the rod due to gas pressure and to decide on a

minimum section to avoid buckling. The designer knows that sharp corners

and rapid changes of section should be avoided and is aware of the likely

manufacturing method.

At the end of the day the designer has to make use of past experience and

intuition to draw a suitable connecting rod. In some ways the worst part of

design is starting with a blank sheet of paper or computer screen.

The rod can next be checked using a computer-based analytical method called

finite element analysis. Here the known loading is applied and the stresses and

deflections calculated. After this calculation the designer might have to

modify the design to reduce the stresses to within acceptable limits. The

material may have to be locally thickened, or even a new concept considered.

Every part of the design has to go through this process, calculations are carried

out, parts drawn, more sums done, the drawings modified, etc.

Discussions will take place with manufacturing engineers; is it possible to

economically make the parts in that form, will that component fit into the

largest lathe, is it possible to remove that blind hole, is it possible to assemble

those parts?

The service department will want to be sure that the product can be easily

maintained.

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Industrial Design

Industrial designers are those concerned with the aesthetic appearance of

products.

Engineering companies concerned with the manufacture of consumer durables

might have an industrial design section (called stylists in the car industry), or

might use external consultants. In heavy engineering the engineering design

staff are often relied upon to produce aesthetically pleasing products, perhaps

one of the designers has a flair for this activity. Whatever system is used, the

aesthetic and functional design should proceed concurrently.

A highly successful manufacturer of automated weaving machines was

working in a market where the traditional designs were very substantially

constructed. Their design solution, through the use of advanced computer

technology, was much lighter than that of their competitors. They were

encountering market resistance from conservative buyers who felt the new

machines looked flimsy. The solution was to appoint an industrial design

consultant who designed a lightweight fibreglass cover for the machine which

looked very substantial, as if it were made of cast iron. The market resistance

disappeared.

Mechatronics

Consideration of the automated loom brings to mind another term that is often

encountered, that of mechatronics. Mechatronics is concerned with the design

of products using a combination of several disciplines, normally including

computers or microcontrollers and mechanical and electrical engineering.

Engineers should be familiar with digital techniques because it is often

possible to offer a more cost effective or flexible solution using a combination

of these disciplines.

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Can you name some products that combine these disciplines to provide a mechatronic

solution?

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________________________________________________________________________________________

Typical mechatronic products include:

• automated cameras

• video recorders

• car engine management systems

• some microwave ovens

• flight simulators for pilot training

• vision systems for automated product inspection

• weaving machines

• robots.

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Detailed Design

Before any parts can be made, more detailed manufacturing drawings and

specifications have to be produced.

During the embodiment stage the designer will have shown the entire product

as a scheme drawing. This will be drawn to scale and will show how all of the

parts relate to one another. It is now time to precisely specify each individual

component.

What information do you think will be needed to allow manufacture to proceed?

Write down your ideas below:

...................................................................................................................................................

________________________________________________________________________________________

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Detailed design has to provide the following:

• precise sizes of all parts and allowable variance, or tolerance, on all sizes

• material specifications for all parts

• numbers required of all parts

• any special process instructions, e.g. paint finish, torque settings and

sequence

• assembly sequence.

If we continue with the connecting rod example, the overall size of the rod has

been specified by the designer, but what about the dimensions of the little end

and big end bearings?

The designer has specified a crankpin of 200 mm diameter, and a nominal

clearance of 0.15 mm. Unfortunately it is impossible to guarantee an exact

clearance of 0.15 mm, as none of the processes involved can consistently and

economically work to an exact measurement. The crankpin has to be turned

and ground, the connecting rod to be bored, and the bearings to be fabricated

and machined. Three different components will therefore need to be made

accurately to ensure a correct clearance.

The designer will have to accept that the ideal clearance of 0.15 mm will have

a variance, or tolerance, to allow economical manufacture. Each of the three

components – rod, bearing and crankpin — will need to be drawn and the

appropriate dimensions specified and toleranced, e.g. the crankpin diameter

might be 200 – 0.03 mm (diameters between 199.97 and 200 mm are

acceptable).

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This application of manufacturing tolerances to components is an essential part

of the detail design stage. It requires a knowledge of the capabilities of the

processes involved and the requirements of the product. Tolerancing will be

covered more fully in a later lesson.

Materials selection is an extremely important part of design. Advances in all

areas of technology have depended upon the development of suitable

materials, e.g. the early steam engines were limited to low boiler pressures

when working with wrought iron boilers. More recently, the development of

heat resisting ceramic tiles and suitable adhesives allowed the safe re-entry of

space vehicles into the earth's atmosphere. Experimental engines are now

using ceramic cylinder components to allow operation at higher temperatures

with lower heat loss – a move towards the highly efficient adiabatic engine.

The materials to be used will need to be specified. A common student gambit

is to describe the material as mild steel or rubber. There are, however,

thousands of types of steel and rubber, and a much more precise definition of

the material is needed. British or International Standards should be consulted,

or possibly manufacturers' data sheets used to give a precise material

specification. Most large companies have a materials engineer on the staff to

assist with the selection, or a supplier will be prepared to give advice, but the

designer will need to be able to communicate with these specialists.

Our connecting rod will be forged from steel, the precise specification might

be to BS 970 part 2, grade 709M40 heat treated to T grade. A bicycle frame

might be made from Reynold's 531 tubing, etc.

In addition to detail drawings there will be parts lists describing how many of

each component are required and where it will be sourced from.

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There might also be process specifications describing in detail how a part is to

be made, e.g. if a part requires a special surface coating then the chemical

process might be described, giving details of times and temperatures, the

chemical used, and any safety advice.

Design For Manufacture

Before the product can be manufactured it will usually be necessary to design

tools and other equipment for use on the shop floor. Where a small

modification is being made to an existing design, this may not require anything

more than the ordering of new cutting tools and the issue of an appropriate

production schedule. At the other extreme, for example, the launch of a new

car, it may be that an entire production line has to be designed and built.

DEVELOPMENT STAGE

Having produced a series of detailed drawings and specifications, it is

normally the practice to build a prototype of the design. The prototype might

take one of several forms.

If the company is confident that the design will be successful, perhaps it only

represents a small or incremental change to a previous model, the prototype

might be almost identical to the eventual production design.

If new technology has been employed, the company might want to carry out

proving trials before spending money on expensive tooling. The prototype

might, in that case, use different manufacturing methods to the eventual

production model, e.g. parts may be welded and extensively machined, rather

than forged or cast. A fibreglass or sheet steel cover might be fabricated rather

than use an injection moulding.

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Some parts might be subject to separate testing procedures, e.g. the connecting

rod might be fitted with strain gauges and tested in a static rig.

The prototype will be thoroughly tested and any necessary modifications made

to the design.

MANUFACTURE

When the prototype has successfully completed its trials, manufacture may

begin. In practice full scale manufacture may be preceded by a series of trial

builds, perhaps resulting in some final modifications to the product design.

CONCURRENCY IN DESIGN

The picture presented here is of an idealized linear design process, with each

activity following another. The real design process is rarely like this, as

problems occur which require an earlier stage to be revisited, the process is

iterative in nature.

Further, many companies are using concurrent engineering, where

multidisplinary teams are involved in the design of products. Here, for

example, the manufacturing engineers will be designing tooling as the design

proceeds, rather than wait for the product design to be finalised. This involves

an element of risk, but greatly reduces the time to market for a new product.

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________________________________________________________________________________________

SELF-ASSESSMENT QUESTIONS ________________________________________________________________________________________

1. A man is burdened by the need to ensure that his dog receives regular

exercise. The dog must walk at least 5 miles every day. Describe briefly

five possible ways that the dog might be exercised.

2. (a) Write down from memory the key stages in the design of a product,

noting the essential features of each stage.

(b) What do you consider to be the most important stage, and why?

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________________________________________________________________________________________

NOTES ________________________________________________________________________________________

...................................................................................................................................................

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________________________________________________________________________________________

ANSWERS TO SELF-ASSESSMENT QUESTIONS ________________________________________________________________________________________

1. Possible solutions are:

(a) the man walks/jogs/runs with the dog for a total distance of 5 miles

(b) the man pays another person to take the dog

food bribes, to run on it every day

(d) the man cycles with the dog alongside

(e) the man sells his dog to a shepherd who uses it in his work.

2. (a) Read the notes!

(b) All stages are important!

Perhaps the most important stage is that of concept design, as that

fixes the key features of the design from the outset. If it is

discovered at a late stage in the process that the concept is wrong,

then at best the project will be delayed, but most probably money

will have been wasted, possibly many hundreds of thousands of

pounds. It pays to spend time to get the concept right, question the

design brief, increase the uncertainty, leave no stone unturned, before

homing in on the chosen solution.

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________________________________________________________________________________________

SUMMARY ________________________________________________________________________________________

An idealized product introduction process might be structured as follows:

• motivation or need, leading to design brief

• design

– concept design

– embodiment design

– detail design

– design for manufacture

• development

• manufacture.

Real design does not follow an idealized route, in most cases there is an

element of iteration as further work means that earlier ideas are no longer

acceptable.

The concept phase is of critical importance, designers need to spend time

examining a range of possible solutions, rather than use the first idea that

springs to mind.

The product brief or specification has to be written carefully to include all the

restraints on the product and the requirements of the market, but it must not

attempt to solve the design problem.

Teesside University Open Learning (Engineering)

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