Whatever the definition of 'good design', it is acknowledged that well designed products are essential for ongoing business success. The most successful companies recognise the importance of a holistic approach to design encompassing functionality, performance, production, aesthetics and ergonomics.

It is possible to design a successful product once through good fortune, good timing or indeed sheer hard work. However, to design innovative and winning products time after time requires a more reliable and structured approach. In many companies, 'good design' is often under-exploited or marginalised., with insufficient attention given to aesthetics, ergonomics or just design for manufacture. Aesthetic design may be undertaken by untrained engineers, industrial designers may be employed too late to make significant difference or products may be designed which are too costly to produce.

Thus, to take advantage of good design, the following collection of 'guiding principles' have been identified as critical ingredients of success.

Selecting the right project for investment is critical to business success. There are a few common mistakes:

Evaluating individual project proposals
As a way of reducing the chances of investing in the wrong project, companies often adopt a formal approach to evaluating project proposals. These approaches address a range of issues, including the commercial viability of a proposal, the relative merit of a proposal (compared to other ideas), the risks and resources.

Equally important is to ensure an appropriate mix of project types and maintain the desired mix of products in the overall portfolio.

Ultimately, the purpose of a structured approach is to authorise investment for further work, based on high quality information. Companies typically use a combination of approaches to evaluating individual project proposals:

Product development is inherently a collaborative activity, involving both internal groups (e.g. Engineering, Marketing, Manufacturing, Sales & Service etc) and external partners (customers, technology suppliers, material/component suppliers, co-development partners, subcontractors, contract manufacturers, sales distributors etc).

Few firms have all the skills and resources to develop technologically complex products themselves. Increasingly, firms choose to concentrate on core technologies and opt to collaborate with others to gain access to complementary skills and resources. Others have experienced downsizing and have little choice but to outsource a number of operations. This may sometimes include design and development activities where the design responsibility for a part or subsystem is either shared or wholly delegated to a third party.

Intra-organisational teamwork
Traditionally, many companies have had a strong functional organisation with projects handed off from one department to the next. This has become known as the 'relay race' or 'over-the-wall' method. More recently, companies have adopted a cross-functional approach ('rugby team') where a core team is responsible for taking the project from concept through to delivery. The core team contains representatives of the most important functional groups, and is augmented from time to time with representatives from other areas as required. This may include suppliers where appropriate.

Inter-organisational teamwork
There are many collaborative forms, ranging from equity relationships such as Joint Ventures or Mergers and Acquisitions at one end of the spectrum to straightforward market transactions at the other. Collaborative product development is an intermediate form where design responsibility is split between two (or more) companies. The resultant product is generally marketed by one of the partners, but may also be marketed by others in non-competitive markets.

Supplier management
Traditionally, supplier management has been a Purchasing responsibility with adversarial or price-based relationships the norm. Increasingly, supplier involvement or partnership is being sought in an attempt to improve the performance of the supply chain. Similar partnerships are emerging in the design chain with various forms of technological collaboration in the product design and development process. Thus design collaborations arise both from the sharing of design and development tasks, and from supplier development or early supplier involvement (ESI). The distinction between these two scenarios is becoming increasingly blurred, as many of the critical issues are common to both.

Improving Collaborative capability
External collaboration is acknowledged to be difficult, but is increasingly being seen to be a fact of life, and the capacity to collaborate successfully can be considered to confer competitive advantage. It has however been recognised that alliances commonly fail because operating managers do not make them work, rather than for technical or contractual reasons. In successful product development collaborations, the contract is seen as a basis for partnership, open to some renegotiation, rather than as a mechanism to guard against mistrust and opportunism. Much is taken on trust in these projects.

In all markets, different groups of customers have different needs. The market for any product can be split into individual segments, comprising clusters of users and customers who have similar requirements, characteristics and tastes. In a well-defined market segment, customers can be viewed as having a similar response to the marketing mix ( P roduct characteristics, P romotional approach, P ricing strategy and P lace of purchase).

Market segmentation and positioning are critical activities in product design and are crucial to ensure that the product features match the requirements of the target customers. The process can be considered in four stages:

Defining the total market
It is impossible to segment a market unless it is first clearly defined. A market can be defined very tightly (for example the small car market) or much more generally (the personal transport market). How a market is defined impacts on the way in which it can be segmented. Thus a segmentation of the personal transport market may include segments called 'small car' and 'bicycle'. Whereas, a segmentation of the bicycle market may result in 'sporting male', 'office worker' and 'family shopping' segments. It is preferable to define a market in a way that will yield useful and definable segments.

Segmenting the market
A market can be segmented in many ways. Effective segmentation aims to identify the needs, purchasing motivations and desires of different clusters of customers. The choices of the bases of segmentation are critical. There is no one correct approach and a market can be segmented by dimensions such as demographics, behavioural characteristics and purchase behaviour, psychographics, geography or benefits.

Benefits based segmentation is often effective as it focuses the mind on why particular groups of customers are motivated to buy your product. It is useful to explore different approaches to segmenting your core market, especially if you traditionally view your products as 'entry level', 'mid-range' and 'high performance'.

The perceptual map
The perceptual map provides a visual way of representing a market and the way in which different clusters of customers or users perceive the importance of different product attributes. Typically, two bases of segmentation are chosen as X and Y-axis of a chart, to enable proposed, current and competitive offerings so be compared. The most effective charts explore the benefits which customers may gain from the product and avoid the need for a 'price' axis, which reinforces the 'entry level, mid-range and premium' perspective.

An alternative approach is to select critical product attributes or elements of the design mix, to enable comparison of the primary competitive characteristics. This can be most appropriate in technology driven products.

An effective perceptual map will enable clusters of users to be identified and preferably named. This is a prime driver in identifying customers to interview, observe or involve in the design of a new product.

Users and customers should be involved throughout product development, from supporting the generation of ideas for future products through to the evaluation of production ready prototypes.

Capturing user requirements
The most critical stage for user involvement is during product definition. It is useful to consider this as a process to focus attention on who interacts with users, how information is gathered, interpreted, organised and communicated. This process includes the following stages:

1) Establish team
Gaining customer insights is not the sole responsibility of marketing or sales. Staff from across the business (sales, engineering, industrial design, production etc) should be involved in user focused research. Each team representative will see different things. The engineer may pick up on technical details, the industrial designer may notice particular ways of working and the marketer may focus on competitive threats. A cross-functional focus can help to build teamwork and generate consensus on the critical product attributes but most importantly enables insights to be generated from different perspectives.

2) Identify stakeholders
A stakeholder is any individual (either internal or external to the company) who is influenced by or has an influence on the design, development, production, distribution or use of a product. It is essential to formally consider who the stakeholders are in order to priorities user, customer and stakeholder research. One specific group of stakeholders of interest is the Lead User. These users tend to face needs that will be in the market place, months or years in advance of other users. They are often dissatisfied with existing solutions and have often tried to modify them to solve their own problems. They are of special interest because then will be keen to invest time (and sometimes money) in the search for a solution to their problems.

3) Plan data collection
It is useful to plan the data collection before embarking on user research. Who will be asked, how many meetings, and who will be involved in them. A simple planning matrix is a useful way of structuring the process and agreeing before hand on the people to be involved.

4) Gather data
There are many ways of gathering data on user needs, wants and perceptions. These range from highly structured approaches such as questionnaires and prepared interviews, through to 'ethnographic' methods such as user observation.

5) Structure & interpret data
Having collected data in the form of completed questionnaires, transcribed interviews, written notes from observations, video footage, still photos or tape recordings, it is necessary to translate this raw data into 'customer needs'. It is possible that a range of methods of data collection have been used to gain different insights. All useful observations should be recorded as a single statement and from the raw statement a user need should be interpreted.

6) Organise, rank, communicate & reflect
If the responses from all customers are translated into 'interpreted needs' then there should be a fair degree of overlap and repetition. Thus, it is useful to compile a single report, grouping where practical similar responses. An aim is to arrive at a single report of interpreted needs, where each need is ranked for perceived importance.

No process is complete unless the results are communicated amongst the team. It is equally important to reflect on the success of the process in order to make improvements for next time - were the right stakeholders involved, were the right staff involved, did we gather the right data, did we use appropriate methods, did we plan the process well?

Having identified the needs of the customers and other stakeholders, the product specification enables these needs to be agreed and communicated within the design team. The specification provides a link between the language of the customer and the language of the business and in particular, the language of the engineer.

A product specification should provide precise, measurable and unambiguous detail about what the product must do, without providing unnecessary constraints or suggesting possible solutions . As a critical document in the design process, it should represent unambiguous team agreement.

The design brief vs the product specification
The design brief describes what the product must be. It outlines the objectives, goals and functions of the required product and does not normally have precise limits; it describes the required product. The brief outlines the product aims, which should be as specific as possible, without indicating solutions or limiting the scope of possible solutions.

In contrast, the product specification defines the required performance of the required product outlined in the brief. The product specification limits the range of acceptable solutions and sets boundaries to the solution space, which later provide a baseline for the evaluation of solutions. The specification aims to provide precise limits to individual parameters, distinguishing between wishes and needs, from both the company's and the users' perspectives.

Thus, the design brief is not the same as a product specification, but is certainly closely related. Ideally, the design brief is a starting point from which the unknown aspects of the product and market can be identified, researched and defined.

Having identified the needs of the customers and other stakeholders, the product specification enables these needs to be agreed and communicated within the design team. The specification provides a link between the language of the customer and the language of the business and in particular, the language of the engineer.

A product specification should provide precise, measurable and unambiguous detail about what the product must do, without providing unnecessary constraints or suggesting possible solutions. As a critical document in the design process, it should represent unambiguous team agreement.

The single page project mission statement
It is common for a development team to rush straight into the production of a detailed specification, without a strong understanding of user needs and the benefits that the project will deliver to the business. A key driver of the product specification is a clear statement of the project mission, focusing on user benefits and customer requirements. The mission statement should indicate the business benefits of the project, including market, financial and even cultural issues. If possible, it is preferable to express the mission graphically, in the form of a product concept brochure. The generation of a shared mission statement can help to build team cohesion and focus the mind on user requirements as opposed to technical features.

It has been demonstrated that the ability of someone to read a brief is inversely proportional to the length of the brief! Thus, it is a good discipline to summarise the project objectives, goals and benefits on a single sheet, along with an indication of the intended role of the industrial designer, maybe following the same major headings as the more detailed brief:

Using visual media and analogies
Several elements of the brief do not lend them selves to written communication. When describing the intangible aspects, it is often most effective to use imagery, analogy and visual means. Traditionally, designers have used images to build 'mood' or 'style' boards, which help support and focus the creative process. Such tools are an excellent way of developing team agreement and understanding over ergonomic and aesthetic issues. Such image boards should be at least A2 size and use images from brochures, professional publications, journals, magazines or the web. Before a session, some preparation is needed to collect together suitable publications. Some examples of how image boards might be used are given below:

Good design is a potent source of competitive advantage and plays a major role in product innovation. However, many small companies lack specialist product design skills so that key activities are often performed by non-specialists or omitted altogether. In some cases, an external design consultancy may be used, but finding the right one and managing the relationship can often be difficult. This is particularly the case with Industrial Design (ID) where many firms either buy-in the service as required, or attempt to do it themselves, which has been described as 'silent design'.

The innovation-styling spectrum
In different markets, the role and perceived importance of ID may depend upon the mode and type of competition. In many consumer product markets, industrial design input is a 'price of entry' and differentiation needs to be gained though novelty or cost. In contrast, many industrial products compete through technical advantage, and ID input can be a key differentiating influence. In both cases, it is vital to understand how ID can deliver competitive advantage and where on the innovation - styling spectrum your company and your competition sit.

This spectrum can be defined as the degree to which industrial design is involved in the product design process, from early involvement in strategy development through to late involvement in product styling.

A company's design ambition can be viewed as the degree to which a company challenges the minimal requirement for industrial design involvement in its market. Typically, companies which display higher levels of design ambition than their competition can gain significant commercial advantage. This suggests that it may not be necessary for all companies to operate towards the innovation end of the spectrum, but to demonstrate sufficiently more design ambition than their competition.

However, whether a company uses industrial design to drive innovation or to re-style products, It is vital that the designer is involved early and throughout the product design process. When ID is viewed as a major contributor to innovation, it is common to have in-house or retained specialist resources, whereas in other cases, external specialists are used often on a project-by-project basis.

Financial and non-financial Benefits
Many companies view industrial design as a high investment, with correspondingly high risks. In reality, the actual investment made by many companies is relatively low compared to the total project spend - often less than 5%. However, it is still viewed as a large external spend. It is of course difficult to isolate the contribution of industrial design to one project, but it is useful to consider the importance of usability and desirability to a project's likely success. It is also essential to be clear whether the investment will significantly enhance product differentiation and the impact on potential sales.

In addition to the financial implications, there are many non-financial benefits to be gained from design investment. These might include enhanced teamwork, early buy in, improved corporate image, cultural change, risk reduction through modelling and prototyping, early visualisation and enhanced customer involvement. The non-financial benefits can often be more significant than the financial ones.

The design mix
An alternative way to value specialist design investment is to consider the aspects of the design mix which are important to commercial success or which drive the consumer's purchasing motivations. In traditional marketing terms, a product can be considered at three levels - the core benefits, the actual product and the augmented product.

By ranking the different elements of the design mix which are important, it is possible to infer the potential requirement for specialist design input. It is also possible to use a similar approach to map the skills available within the company and also to rank competitive products.

Before beginning a product design project, thought should be given to the potential role of industrial design. What are the potential benefits to be gained and how do we begin to plan the engagement. Activities during this stage include:

Identify the type of ID required
- How important are human factors or user interface issues?
- How important is creativity and innovation?
- Is the work primarily styling?

Plan engagement
- What is the scope of the potential project?
- Establish the selection criteria
- Draft an initial brief

Finding and selecting a designer
Before beginning the search, it is crucial to identify the selection criteria which can later be used when evaluating the pros and cons of different possible suppliers. These criteria will differ from company to company, but will include elements such as location, price, specific skills, IT and communication, track record and personality or rapport.

Often, designers are chosen based on word of mouth or previous experience. However, it can be difficult to locate the right designer with the right skills. Alternative approaches include design directories, web links and the local Business Links design councillor. If all else fails, seek out examples of products that you like and contact the manufacturer to identify the industrial designers involved.

As a rule of thumb, between 5 and 10 candidates should be identified and 3 of these asked to respond to a draft brief. It is essential that all team members support and agree the final choice, especially those who will be working closely on a day to day basis.

During this stage, there will be an iterative development of the brief and the proposal from the selected industrial designer. Ideally, the final brief should be co-developed to ensure that the content and deliverables are appropriate and agreeable to both parties. Make sure that the final proposal satisfies the requirements of the project and has clear, measurable deliverables at the end of each phase.

Managing the relationship
As the project progresses, the relationship between the engineers and industrial designers becomes increasingly important. It is vital that all concepts are jointly supported and are feasible and producible. Managing the relationship demands a joint appreciation of the following issues:

Project responsibilities & plan
- Knowing who is responsible to deliver which aspects and when
- Breaking the project into discrete phases

Product interface management
- Having an agreed approach to change management
- Identifying the system architect
- Task partitioning based on an understanding of the interfaces between components, modules and sub-systems

Risk / problem management
- Identifying and managing the technical, commercial and market risks
- Being aware that difficulties inevitably happen and that a shared solution maybe even renegotiation is always more effective than blame and 'finger pointing'

IT management
- Ensuring IT compatibility and effective data transfer

Communication
- Identifying the modes of informal and formal communication between internal and external team members, including scheduled meetings and design reviews

Typically, this proliferation is due to poor planning of the product range, little connectivity between different development teams working on different products and ineffective reuse of technology. A common result from this lack of planning, during product design is the development of highly efficient manufacturing processes to compensate.

A key to delivering cost effective products is to provide users and customers with the greatest possible variety of solutions, whilst minimising the production complexity within the business, through the reuse of technology, parts and processes.

Hierarchy of design decisions
The variety of product offerings and the relationship between these products is a strategic business issue, which must be considered prior to the start of any individual project. Product platform planning requires a systematic consideration of markets and available technologies in order to establish those technologies which can form the basis of different product offerings in different market segments.

Later in the design process, opportunities for reuse of technology reduce. During the concept design stage, the key trade off is between the level of modularity or integration in the product design. The decision to develop a modular product is linked to several key business issues:

During the detailed design stage, it is important to consciously design for the reuse of components and processes. Wherever possible, production processes including tooling decisions and assembly methods should be consistent. A proliferation of tooling requirements can be as costly as a proliferation of parts. Likewise, components should be standardised wherever possible, including fasteners. Only when the opportunities for part or process reuse are exhausted should a component be designed to be consciously different.

Prototyping has been described by Tom Kelley of IDEO design consultants as 'the shorthand of innovation'. Effective prototyping is arguably one of the most critical skills in product design.

Prototypes serve three main purposes:

2) Reducing technical risks

3) Building team confidence and buy-in

Types of prototype
Prototypes can take many forms, from very simple mock-ups or visualisations to demonstrate a principle, through to sophisticated pre-production products and detailed analytical simulations. Different types of prototypes can be utilised for different purposes, as outlined in the table below.

Prototype fidelity vs cost
The fidelity of a prototype can be defined as how accurately the prototype represents either functionality (or performance), appearance, producibility or usability. A model with high fidelity will closely mimic the characteristics of the final production item. There is clearly a trade off between fidelity and cost. Typically, the greater the fidelity, the higher the cost. For example, a simple card model of a casting may have low fidelity compared with a full FEA model but it is also significantly quicker and cheaper to produce. Examples of fidelity vs cost are illustrated in the table below.

Rapid Prototyping (RP)
Since the introduction of Stereo-lithography in the late 1980s, RP has come of age. Representative parts and tools can be produced almost instantly directly from CAD data. RP provides speed, accuracy, and the ability to produce components with complex geometry which would otherwise require expensive tooling. This has provided new opportunities for designers to test ideas and concepts increasingly quickly. There are three core techniques:

• Stereolithography
  The original and most popular RP process. The model is built up in layers in a bath of photo-curable epoxy resin, which is solidified by laser. Produces accurate, strong and translucent parts.

• 3D Plotting
  Utilises a print head to either fuse a powder or deposit molten material (wax, ABS) in layers to build up a component, section by section. The process can be viewed as similar to ink jet printing with the ability to build in the vertical direction. Especially suitable for small intricate parts.

• Laminated object modelling (or Adhesive RP)
  Layers of either ceramic, paper or plastic sheet are bonded together, with each layer being cut to the required sectional profile with a laser. Completed models have a wood like feel and can be used as either tooling or concept models.

There are literally dozens of different 'Design for X' methodologies, which are often of greatest interest in specific markets or for particular types of product. However, 'Design for manufacture' and 'design for assembly' remain the most important as they have a direct and recognisable impact on product costs.

Design for Manufacture
Design for manufacture (DfM) can be considered more as a philosophy than a specific activity to be carried out during the design process. It is a way of thinking, which can be applied at a component, product or product family level. The primary objectives are to minimise the overall component count and to optimise the components which remain, with the goal of reducing the overall manufacturing costs. Thus, central to the overall philosophy is a clear understanding of the drivers and contributors to unit cost and specifically, the relative trade-off between manufacturing processes based on production volume and apportionment of fixed and variable costs. DfM can be viewed as having three key elements: process selection, reducing the number of process stages and designing for the process.

Process selection
Involves the analysis of both material and processing method for individual components, based on basic assumptions:

Critical performance criteria (conductivity, strength, friction, thermal properties etc)
Tolerancing requirements
Component complexity requirements
Set up and tooling costs - apportionment of fixed and variable costs
Production volume
Expertise and capability
Reducing the number of process stages
Eliminating unnecessary process stages, through a combination of alternative strategies:
Component minimisation
Elimination of finishing processes
Combining processes
Single direction processing or machining to reduce set up requirements
Designing for the process - guidelines

There are many design guidelines which aim to ensure optimum detailed design of components to satisfy the constraints of specific production processes. These guidelines help designers to exploit the benefits and recognise the limitations of processes whilst also preventing basic errors. They can be viewed as capturing 'good practice' for individual processes and are often 'common sense' heuristics, which generally hold true - although there are always exceptions.

Many guidelines are publicly available, although companies frequently develop their own rules to support their own production facility. Typical examples include: machining guidelines, casting guidelines, injection moulding guidelines, sheet metalwork guidelines, welded joint guidelines, adhesive guidelines etc.

In practice, guidelines can be inaccessible and difficult to use. There are literally hundreds of different guidelines, for all conceivable processes. They are frequently book based, although increasingly, computerised guidelines are available. It can be much more advisable to directly consult the process experts when designing individual components.

Design for Assembly
Design for Assembly (DfA) can be viewed as a major subset of the DfM approach, and supports the DfM goal of minimising the total number of components. In addition, DfA techniques aim to maximise the ease with which parts can be moved, held, located and joined. There are two basic approaches to considering DfA:

DfA - guidelines
Like the guidelines for DfM, there are a wide collection of DfA guidelines. These guidelines tend to take basic design rules and expand upon them with graphical examples of 'bad designs' and suggestions of improved 'good designs'. Typical rules include minimise part count, designing out wires and cables, design out adjustment, maximise part symmetry, insert parts from the same direction, eliminate fasteners and do not assemble in enclosed spaces. Like the guidelines for DfM, they suffer from inaccessibility and can be difficult to use in practice

DfA - Systematic approaches
Systematic approaches aim to provide a structure to analyse an assembly and focus the decision making process. There are various methods, but best known are the Boothroyd & Dewhurst method developed in the 1970s and the Lucas Engineering Systems method developed in the 1980s. Typically, a systematic approach begins with an analysis of the assembly to determine if parts can be eliminated or reduced, based upon some simple rules:

Is there relative movement between one part and another?
Does the material need to be different for functional purposes?
Does the part need to be replaced or maintained?

The second stage is to map the assembly sequence and rigorously assess each component for difficulty of handling (or feeding for automated assembly), insertion and fitting (locating or securing). This assessment is based on tables of data which provide relative measures depending upon the design of the components.

Implications of DfM and DfA approaches
It is impossible to make sensible DfM and DfA decisions without first knowing the desired unit cost and making a rough estimate of the unit cost of proposed design solutions. This requires a knowledge of manufacturing volumes in order to balance fixed and variable costs.

While many of the DfM and DfA principles can be applied irrespective of production volume, the basic philosophy of minimising component count can have implications for products which are produced in low volume. A logical impact of component reduction is that there are fewer, more complicated parts. These parts may ultimately have a lower piece part price, but at the expense of higher tooling costs. It can often be more appropriate to have more parts with correspondingly lower tooling costs for low volume production.

A further complication is the potential conflict between DfM and DfA approaches and product platform or modularity strategies. In order to achieve a modular product range, the interfaces between modules need to be clearly defined. This often results in additional components, costs and hence complexity. It is often not possible to both minimise component count and deliver a modular solution.

Minimising complexity of design
It can be useful to view the act of designing a new product as adding logistic complexity to the business. Every new component, assembly or process results in time, effort and cost to the business. Thus, when designing a new product, a useful metric to monitor is the level of complexity introduced. This can be assessed through considering the number of new purchased parts, manufactured parts, processes, vendors and tools required. This 'complexity scorecard' can assist in both assessing alternative designs, as well as focusing attention on component and process reuse