Design for eXcellence

Unit 6: New product introduction

Section 2: Tools to make the NPI process more efficient

Section Contents


We saw earlier how the electronics industry is under pressure to maximise profits. To do this, an organisation will strive to reduce development and manufacturing costs and time, produce the best quality products and, therefore, satisfy the customer. Implementing tools and philosophies to be used during NPI can fulfil these requirements within the NPI process.

Shown in Figure 1 is a diagram of a typical product development process, with some of the popular tools used during each phase shown in grey.

Figure 1: The product development process with some suggested tools for each phase

The product development process with some suggested tools for each phase

For the purposes of this study, we will consider three areas that the tools affect:

Quality Engineering Tools. These work throughout various stages to ensure the product is of the best quality.

Product Design Tools. These would be used predominantly during the design functions, to ensure that the right product is specified and designed and to reduce design time and costs.

Manufacturing Tools. These would be used during the manufacturing phases, including process design and prototyping, to reduce manufacturing costs and times.

Most of the tools affect more than one phase. For example, QFD can be used throughout the process as shown in Figure 1. Also tools like DFM require information feedback procedures from the manufacturing phase to design phase. We can see that we need close integration between phases.

At this point we will consider Concurrent Engineering separately because the method advocates the close integration between all phases with regards to information and resources.

Activity: Concurrent Engineering

Figure 2 represents the serial development process. The grey area is the amount of knowledge acquired of the design during first, the design process and then the manufacturing process. The communication link between the two stages is after the design has been approved for manufacture.

Think about and list the advantages of this sequential process. Redraw the figure so that the process is concurrent and list the advantages of this method of development.

Compare your answer with the discussion that follows


Figure 2: The serial product development process

The serial product development process

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Concurrent Engineering

Product development consists of the movement of a product idea from concept through to market availability. This process involves a number of distinct phases and has traditionally been viewed as a linear process involving individual, predetermined steps, each of which required completion and sign-off before subsequent stages could begin. The design and manufacturing phases for a serial process are shown in Figure 2.

The grey area is the amount of knowledge known of the design during first the design process and then the manufacturing process. The communication link between the two stages is after the design has been approved for manufacture. It also shows the steep learning curve required during manufacture.

The sequential approach is held to have several advantages:

  1. The distinct stages make the process easy to manage and control since each stage is predetermined and can be reviewed.

  2. Uncertainty is reduced before the next phase begins, since the information received downstream is complete and signed off.

  3. The approach optimises functional expertise, since each department focuses on a limited number of tasks and engineers (or designers) can participate on a number of projects simultaneously.

However, this approach has its drawbacks:

  1. The separation of expertise can result in products that are difficult to make since manufacturing expertise only enters the process once the design has been finalised

  2. It is inappropriate for customers because, due to the separation of design from marketing, there is the possibility of designing a product which does not satisfy the customer.

  3. It is slow to reach the market since all stages must be complete before the next can begin. Procedures have to be established that deal with problems that arise after handover.

An alternative approach, shown in Figure 3, is to consider these various stages as overlapping, co-operative and iterative. The dotted box represents the involvement of manufacturing in design problem solving. It shows the improved communication between the two phases.

Figure 3: The concurrent development process

The concurrent development process

This approach of over-lapping and integration of design, development, prototyping and manufacturing is known as ‘simultaneous engineering’ or ‘concurrent engineering’. This overlapping and integration reduces total development time because downstream activities receive resources prior to completion, but after the start, of the upstream task. Manufacturing companies have realised that to reduce quality problems and production costs, designers and manufacturing engineers must work together at the early stages of product design.

The concept is very simple but execution is more difficult. To be successful, simultaneous engineering must be underpinned by:

The main objectives of Concurrent Engineering are:

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Quality Engineering tools

Figure 4: A disciplined approach to quality

A disciplined approach to quality

The flow diagram in Figure 4 shows how the various Quality Engineering methods may work together to achieve a disciplined approach to ensuring quality. QFD gathers the needs of the customer and prioritises where improvements are needed. Taguchi provides the mechanism for identifying these improvements and SPC contributes the means to hold these gains as well as to otherwise ensure continuing quality improvements.

Quality Function Deployment (QFD)

Figure 4 shows how QFD is used in a quality system: customer needs feed QFD and it translates the voice of the customer into identified key product and process characteristics.

Introduced in Japan by Yoji Akao in 1966, QFD is a technique that aims to capture what the customer needs, and work towards how it might be achieved. In 1990 Akao described QFD as ‘a method for developing a design quality aimed at satisfying the consumer and then translating the consumer’s demand into design targets and major quality assurance points to be used throughout the production phase’.


QFD is a way of listening to customers to learn exactly what they want, and then using a logical system to determine how best to fulfil those needs with available resources. It is a product-development tool that translates customer requirements into design and production requirements. QFD ensures that everyone works together to give customers what they want and it gives everyone in the organisation a road map showing how every step, from design through delivery, interacts to fulfil customer requirements.

QFD’s primary goal is to overcome three major problems in traditional methods: disregard for the voice of the customer, loss of information, and different individuals and functions working to different requirements. In QFD, these issues are addressed by answering the following questions:

A disadvantage cited by practitioners is the complexity involved in using QFD in large design projects; the number of factors used in each axis of the matrix must be minimised if the process is not to become unmanageable. Conversely, if the number is artificially restricted too severely, important relationships may be overlooked

The four phases of QFD

The QFD system consists of the four phases that are summarised in Figure 5:

Figure 5: The four phases of QFD

The four phases of QFD

The QFD process involves mapping customer requirements onto specific design features and manufacturing processes through these four matrices. QFD can be employed at two levels:

The first level typically involves the first of these matrices (Figure 6). This matrix has the most general structure and is often called the ‘house of quality’ (HOQ). Typically applications of QFD are limited to the HOQ, however QFD can play a greater role as a linking mechanism throughout product development through the use of subsequent matrices.

The four phases of QFD help communicate product requirements from the customers to the design team to the production operators. Throughout the phases, all participants are able to assess how solutions would help to satisfy customer requirements. All decisions are based on the highest level of customer satisfaction. The four phases provide a guide through the product development cycle from product design to production.

Each phase has a vertical column of Whats and a horizontal column of Hows. Whats are customer requirements and Hows are ways of achieving these requirements. Hows that are most important, require new technology, or involve high risk are carried forward to the next phase.

In the Design Phase, the customer helps to define the product requirements. The Hows carried over from the Design phase become the Whats for the Details Phase and design specifications are converted into individual part details. In the Process Phase, the processes required to produce the product are developed. The Hows from the Details phase become the Whats for the Process Phase. The Hows from the Process phase become the Whats for the Production Phase and the production requirements for the product are developed.

Figure 6: The House of Quality

The House of Quality

First, customers’ requirements (which form the vertical axis of the matrix) are matched with the design attributes (which form the horizontal axis of the matrix). The individual elements of the matrix are used to indicate the degree and direction of influence of the main design attributes on customer needs. To do this some kind of coding scheme is used. This is often pictorial using, for example, circles and triangles. (It is important at this stage to clearly record all assumptions used in judging the nature of these relationships.) The purpose is to make explicit what, without QFD, might have remained unexplained in the design process.

Some benefits include: provides a systematic approach in addressing the customer’s wants and acts as a driver for other techniques such as FMEA, Taguchi, SPC; moves changes upstream where they are more economically accomplished; provides a valuable company record for the next product cycle; promotes teamwork and shared responsibility.


It is being increasingly recognised that the high quality of a product or service and the associated customer satisfaction are the key for enterprise survival. Every product feature or characteristic has a nominal or target value. Any deviation results in higher costs to the consumer and producer, which is what Taguchi called the ‘Loss to society’. The never-ending goal is to reduce variability and hit the target. These ideas arise from development work undertaken by Dr Genichi Taguchi whilst working at the Japanese telecommunications company NTT in the 1950s and 1960s. He attempted to use experimental techniques to achieve both high quality and low-cost design solutions.

The word quality cannot have a specific meaning when applied to the manufacturing industry. This is basically because the word quality changes within the context it is being used. For a long time, manufacturing industries in European and American countries have worked from the basis of a tolerance. This tends to suggest that the manufactured item would be passed as acceptable if its quality was within the specified tolerance range.

Taguchi’s response to quality differs rather greatly from the goalpost philosophy of the European and American countries. The Japanese implementation of Taguchi’s concept sees them working on the principle that when designing a product, it should be designed with minimum loss, with the relative product being designed as close to the optimum value as is feasibly possible. This would result in the product being manufactured with regard to its life cycle and customer satisfaction from the design stages. It would also mean that less repair work would be required in the long run.

The definition of quality given by the Taguchi methodology is customer orientated. Taguchi defines quality in a negative manner:

Quality is the loss imparted to society from the time the product is shipped.

This loss would include the cost of customer dissatisfaction that leads to the loss of company reputation. This differs greatly from the traditional producer-orientated definition that includes the cost of re-work, scrap, warranty and services costs as measures of quality. The customer is the most important part of the process line, as quality products ensure the future return of the customer and hence improves reputation and increased market share.

The fundamental Taguchi concepts

In general, there are four quality concepts devised by Taguchi:

The Taguchi methods

Taguchi’s main objectives are to improve process and product design through the identification of controllable factors and their settings, which minimise the variation of a product around a target response. By setting factors to their optimal levels, a product can be manufactured more robust to changes in operation and environmental conditions. Taguchi removes the bad effect of the cause rather than the cause of a bad effect, thus obtaining a higher quality product.

Taguchi’s philosophy is centred on three concepts for improving quality of design:

Robust Design: One measure of a product’s quality is its ability to maintain consistent performance over a range of conditions, regardless of variations in the way it is manufactured and used. The Robust Design concept can improve product quality without increasing manufacturing costs.

Taguchi suggested that the design process should be seen as three stages:

  1. Systems design identifies the basic elements of the design, which will produce the desired output, such as the best combination of processes and materials.

  2. Parameter design determines the most appropriate, optimising set of parameters covering these design elements by identifying the ‘settings’ of each parameter that will minimise variation from the target performance of the product.

  3. Tolerance design identifies the components of the design that are sensitive in terms of affecting the quality of the product and establishes tolerance limits which will give the required level of variation in the design.

Design of Experiments (DoE): Taguchi advocated the use of statistical methods concerned with the analysis of variance, and constructing experiments that enable identification of the important design factors responsible for degrading product performance. Taguchi methodology emphasises the importance of the parameter design in the total design process – a stage often neglected in industrial design practice. The methodology involves the identification of those parameters that are under the control of the designer, and then the establishment of a series of experiments to establish that subset of those parameters which has the greatest influence on the performance and variation of the design. The designer thus is able to identify the components of a design that most influence the desired outcome of the design process.

Quality Loss: When judging the effectiveness of designs, the degree of degradation or loss is a function of the deviation of any design parameter from its target value. The second related aspect of the Taguchi methodology – the Taguchi Loss Function (Figure 7) maintains that there is an increasing loss (both for producers and for society at large), which is a function of the deviation or variability from the ideal or target value of any design parameter. The greater the deviation from target, the greater is the loss. The concept of loss being dependent on variation is well established in design theory, and at a systems level is related to the benefits and costs associated with dependability.

Figure 7: Taguchi Loss Function

Taguchi Loss Function


Self Assessment Questions: Taguchi

Taguchi advocated five guidelines to achieve best product quality. Can you list them?

Compare your list with ours.

Statistical Process Control (SPC)

With SPC methods, and periodic process inspection, we can determine whether a process is staying in control or is potentially moving out of control at a given point in time. Given that we have a good process (designed with the help of QFD and Taguchi), we then use SPC as a tool to monitor the process and make sure it does not change. If we decide to employ SPC then it is implied that the process is desirable and should be retained.

Variation in processes

There are changes in production output from one unit to the next (which may be small) and this continuous variation has two basic causes:

  1. Common Causes are variations due to operating environment (temperature, humidity and atmospheric pressure), small equipment vibrations, small variations in the materials used and so on. When a process varies in such a way, over time these variations become predictable. In general, as long as the outputs of a process lie within the expected amount of variation (from common causes) then the process is said to be in control.

  2. Special Causes are abnormal and cannot be predicted. In a manufacturing process special causes are excessive machine or tool wear and drifting from calibration, an inferior batch of raw materials, a poorly trained operator or an incorrect work method. Any of these cause variation in the process output and unless rectified could harm the output quality of the process. Whenever a process is judged to have been influenced by a special cause, it is said to be out of control.

SPC procedure

The SPC procedure is as follows:

  1. Periodically select a sample of items from the process, inspect them and note the result.

  2. Determine whether the cause of variation in items is a common cause or a special cause.

  3. Take appropriate action depending on the result of (2). For variations that result from common causes, usually nothing is done. For variation from special causes immediate action is necessary to find the assignable cause and rectify it.

To enable this procedure we use control charts.

Control charts

There are several different kinds of control charts, each used to monitor different process traits.

Basic control chart

This is used to show variations of sample data against time or sample number. It would be used if the process is well established and statistical information is known about the process (mean and standard deviation). If we assume that the process limits are 8.2 and 8.6 with a mean of 8.4 then they can show if a process is in control (Figure 8) or out of control (Figure 9).

Figure 8: Control chart showing an in-control process

Control chart showing an in-control process


Figure 9: Control chart showing an out-of-control process

Control chart showing an out-of-control process

X-bar and R charts

If a process is not well established then X-bar chars will show how the average of a process sample data varies. To complement the X-bar chart (they are usually used together) an R chart is a plot of the variation in the sample data. Any drift in the averages (the averages rise or fall) or excessive variation between samples would prompt investigation.

Figure 10: The X-bar and R charts

The X-bar and R charts


Self Assessment Questions: Statistical Process Control

Statistical Process Control is a philosophy that uses plotted process measurements to determine the state of the process.

  1. Describe the two causes of variation in a process. Incorporate in your answer definition of in control and out of control processes.

  2. Suggest two types of control charts and their uses.

  3. The table below shows the solder temperature measurements taken from a wave soldering process every 5 minutes over a 100 minute period. The specification for the solder temperature is 248 ± 2°C. Plot the Control Chart (measurement against sample time) for the 20 measurements including the upper and lower specification limits. Is the process in control or out of control?
Sample Temperature
Sample Temperature

Compare your answer with this one.

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Product Design Tools

Value Analysis or Value Engineering (VA/VE)

VA/VE is an approach to productivity improvement that attempts to increase the value obtained by a customer of a product by offering the same level of functionality at a lower cost. Value engineering is sometimes used to apply to this process of cost reduction prior to manufacture, while value analysis applies the process to products currently being manufactured. The terms are interchangeable; both attempt to eliminate costs that do not contribute to the value and performance of the product.

VE/VA originated in General Electric (under Lawrence Miles) during the Second World War. GE were seeking ways to make the most efficient use of war-limited funds and raw materials. They found in most cases alternative materials and processes performed at least as well and often better in terms of both specification and cost. This led them to formalise the approach and devise a team-oriented technique that determines the ‘value’ of each part and each product. Value engineering, thus, critically examines the contribution made to product value by each feature of a design. It then looks to deliver the same contribution at lower cost.

The Value Method

Value engineering programs are best delivered by multi-skilled teams consisting of designers, purchasing specialists, operations personnel, and financial analysts. Pareto analysis is often used to prioritise those parts of the total design that are most worthy of attention. These are then subject to rigorous scrutiny. The team analyses the function and cost of those elements and tries to find any similar components that could do the same job at lower cost.

Common results are a reduction in the number of components, the use of cheaper materials, or a simplification of the process.

Several characteristics differentiate the Value Method from other techniques. These help ensure that the customer obtains the kind of product they need and want.

Value-based decision process

Comparisons of worth and value as opposed to Life-Cycle Costs. Different types of value are recognised by the approach:

Use value relates to the attributes of a product that enable it to perform its function.

Cost value is the total cost of producing the product.

Esteem value is the additional premium price that a product can attract because of its intrinsic attractiveness to purchasers.

Exchange value is the sum of the attributes that enable the product to be exchanged or sold.

Although the relative magnitude of these different types of value will vary between products, and perhaps over the life of a product, VA/VE attempts to identify the contribution of each feature to each type of value through systematic analysis and structured creativity enhancing techniques.

Use of the function analysis approach

Function analysis is concerned with locating unnecessary costs and specific requirements (or other project driven characteristics) and determining the value of the project selected for study. A function is that which makes an item or service work or sell – in other words, an item’s function is why the customer buys the product or service. An item, including structures and services, is a means to the end of providing a function, not the end itself. In using the function approach, the value study team constantly returns to the primary reason for design and build cycles –the ultimate use of the item. Customers buy a product or service because it will provide a function that satisfies their need at a cost they are willing to incur. If, as is almost always the case, they wish to minimize their total cost they must look beyond price and consider other costs – operational, maintenance and usage.

Follows a very systematic and organized procedural process – the Job Plan

The Job Plan consists of five phases:

Failure Modes and Effects Analysis (FMEA)

Product failures through design or manufacturing faults are costly both in monetary terms and in the customer’s perception of the product and manufacturer. Therefore a multifunctional approach to product system analysis, done in a timely manner, provides a valuable guard against the introduction of poor products. FMEA is a structured approach to the identification and evaluation through a ‘risk priority number’ (RPN) of possible modes of failure in a product or process design. The RPN delivers a list of prioritised failure modes to be considered during design. Failure is taken in its broadest sense, not as a catastrophic breakdown but as a consequence of not meeting a customer’s requirements. The aim is to anticipate and design out all possible failures before they occur, removing the cost to manufacture, warranties, and customer satisfaction. It can be used from design through to production.

The purpose of FMEA is to:

Design FMEA: uncovers potential failures associated with a product that could cause product malfunction, shortened life or potential safety hazards.

Production FMEA: uncovers potential failures that can impact on product quality, reduce process reliability, create safety hazards and ultimately cause customer dissatisfaction

Design for Manufacture (DfM)

It should go without saying that a design team needs to consider the manufacture of a product, but, all too often, products enter manufacturing with problems that are expensive to put right and could have been avoided if the manufacture of the product had been considered at an early stage. Areas for consideration might include:

Careful consideration of these issues, in conjunction with manufacturing engineers, at an early stage in development can pay great dividends when the product enters manufacturing. It will reduce manufacturing time and costs by reducing or eliminating problems generated by a design that has not been assessed for manufacturability during the design stage.

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Manufacturing Tools

Lean Manufacturing

Basic definition

Lean practices attempt to reduce waste throughout every component of the manufacturing process. Though the term ‘Lean Manufacturing’ was coined by James P. Womack in his MIT study (The Machine That Changed the World : The Story of Lean Production) looking at the automotive supply chain, it originated in Japan with Toyota.

Lean Manufacturing is an operational strategy oriented toward achieving the shortest possible cycle time by eliminating waste. It is derived from the Toyota Production System and its key thrust is to increase the value-added work by eliminating waste and reducing incidental work. The technique often decreases the time between a customer order and shipment, and it is designed to radically improve profitability, customer satisfaction, throughput time, and employee morale.

The benefits generally are lower costs, higher quality, and shorter lead times. The term ‘lean manufacturing’ is coined to represent half the human effort in the company, half the manufacturing space, half the investment in tools, and half the engineering hours to develop a new product in half the time.

The characteristics of lean processes are:

In his book, Toyota Production System; Beyond Large-Scale Production, Taiichi Ohno identified seven basic types of waste:

  1. Overproduction

  2. Waiting

  3. Transportation

  4. Processing

  5. Excessive Inventory

  6. Unnecessary Motion

  7. Making Defective Products

Lean Manufacturing tools

Lean manufacturing is an umbrella term for a variety of tools. The following are the more frequent tools employed.

  1. Just-in-Time (JIT) – ‘pull’ system – parts are brought to the production work site only when needed.

  2. Kanban – ‘pull’ system – Japanese method that uses carts, or kanbans, that hold the minimum amount of inventory needed on the plant floor.

  3. Continuous Flow Work Cells (a.k.a. Cellular Manufacturing) – collocate machines, equipment, tools and people necessary to complete a product in one work setting.

  4. Set-up Time and Maintenance Reduction – reducing machine downtime by training each worker who uses a machine how to set-up, maintain and clean the machines; keeping all parts required for set-up near the machine.

What companies practising lean manufacturing do:

About companies that practice lean manufacturing


Shigeo Shingo (an engineer involved in the Toyota Production System) invented the Poka Yoke mistake proofing system. In that system he advocates three interrelated aspects of quality control:

Zero Quality Control is the ideal production system in which no defects or errors occur. It is based on the following basic ideas:

Source inspection – although no amount of inspection will ever prevent defects from occurring during a process, enough inspection will reveal the source of the defect. That being the case, these sources can be monitored and eventually eliminated. Eliminating the source of a defect is equivalent to eliminating the opportunity for the defect to ever occur again.

Poka-Yoke uses devices during the production of products so that if a worker forgets to do something the device will signal the fact, preventing errors or defects from occurring. The concept is the same as ‘fool-proofing’ where the assembly, manufacture or operation can only be performed one way – the correct way.

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The NPI process can mean the difference between an organisation’s success or failure. It is therefore in the interest of every organisation to spend time, money and resources on ensuring the process is as efficient as possible. An efficient NPI process would ensure that:

Tools can be used to achieve this. The tools used whether they improve costs, time or quality during design and manufacture always involve a culture or base philosophy change and as such are not implemented overnight. They involve full management and staff participation and commitment, the following of new procedures and practices and a culture of continuous improvement to possibly unachievable goals. To ‘strive for perfection’ is to stay ahead of the competition by producing better quality products quicker and at the lowest cost.

Self Assessment Questions: The successful New Product Introduction process

  1. What are the requirements for a successful NPI process with respect to the product/process and the customer?

  2. The tools described in this unit improve the New Product Introduction process in terms of quality, cost and time. Some are used in the design phase and some during manufacture. You are part of a team redesigning a product and introducing it to market substantially faster than the current model. If you have experience with a suitable product then use this as an example.
    • How could you use tools in the design phase to reduce the overall development time?

    • What are the likely obstacles you will face?

Compare your answer with this one.

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