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Engineering Method

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December, 2003

All humans are engineers. Humans engineered the civilization from nature. By engineering we assert our freewill. We intend to engineer a better world in this random universe. The subject of this paper is the method with which we engineer.

Engineering implies a method. A method to design, to improve, or understand a product. We are aware of the scientific method: hypothesis, experiment, and theory; however, the method implied in engineering is not formalized. Thus, I emphasize the Engineering Method.

The Engineering Method is an approach for problem solving or a way to produce an end -product. Engineering a product is a function of the following factors: resources (finance, labour, equipment), time, knowledge, market conditions, and government regulations. A product is engineered to promote our physical survival (a needed product), to enhance our living arrangements (a convenient product) or to fulfill our technological enthusiasm (an amusement product).

Historically, engineering was associated with craftsmanship. Temples, forts, dams, roads, weapons, and sculptures are examples of traditional engineering products. However, the emergence of engineering as a profession, and the systematic application of science to engineering started in the late 19th century. Edison, the legendary inventor of that time is credited with the invention of the "invention method". The "invention method" refers to Edison building the Menlo Park laboratory, bringing together scientists and craftsmen, and identifying and developing breakthrough devices and systems. Today, most products are engineered and manufactured by small and large companies, and most engineers are professionals. Engineering has become an integral feature of the companies.

Companies have their distinct cultures or Engineering Methods. Research groups such as Engineering Design Research Center (EDRC) at Carnegie Mellon and Center for Design Research at Stanford study and develop engineering or design methods. Nigel Cross and Martyn S. Rayare are notable for their suggestions for Engineering Methods. Also, there exists systems such as TRIZ, which can be considered as Engineering Methods. However, the Engineering Method that I want to discuss is the general approach, the system, steps or the attitude that an engineer takes in solving a problem or designing a product. I intend this paper to be a guide in illustrating the steps required in engineering a product. My experience as an engineering student at Ryerson, and the literature review on Engineering Methods are the basis for this paper. I intend to revise this paper upon acquiring more experience and information.

There are many levels of engineering activities. NASA engineers the Viking to explore Mars, a student engineers a remote controlled toy plane, and a hobbyist engineers a kite. Irrespective of the level or complexity of the engineered product, there exists an underlying approach or method implied by engineering. Also, a complex product is usually broken down into its component systems, and the component systems are engineered and integrated. Thus, my focus is the individual engineer or a small team and what method can be used to solve a problem or engineer an end-product.

Do I seek a method to engineer novel products? Yes and No. Innovation does take place in the engineering context and culture. However, much of the elemental engineering activity is adaptation rather than innovation. Innovation is equivalent to breakthrough in science. Adaptation is improvement or modification of the existing products or systems, which can be defined as small-scale or minor innovations.

Characteristics of the Engineering Method
A discussion about the type of engineering problems aids in understanding the characteristics of the Engineering Method. Nigel Cross distinguishes two types of problems: well defined problems and ill defined problems. The characteristics and domains of the problems are summarized in the following table. Nigel Cross further notes that engineering or design problems are usually "ill defined", thus without "definite formulation" or solution, possibly with internal conflicts, and "solution dependent".

Well defined problems Ill defined problems
Problem focused methods Solution focused methods
Solving the problem involves understanding and formulating the problem accurately, appropriately, and in detail; then applying algorithmic solutions
Solving the problem involves trying to "move fairly quickly to a potential solution, or set of potential solutions, and to use that as a means of further defining and understanding the problem.", and solving it (1)
Science and mathematics Engineering or design
A doctor needs to diagnose his patient accurately before he/she can treat the patient.

An engineer need to propose a system for home security before the tenant can demand customization, adjustments or assurance.

Engineering problems are "ill defined", thus without deterministic solutions. Thus, Engineering Method is not completely systematic. The method is not a recipe to produce hot selling products. Nevertheless, the Engineering Method does produce buildings, bridges, vehicles, software, tools, and devices that function reliably, and we use confidently. Then, what exactly are the characteristics of the Engineering Method? The three main characteristics of the Engineering Method are: heuristic, iterative, and use of Science.

The Engineering Method is heuristic because there exists no one method, and none of the methods can be proved theoretically, mathematically, statistically or otherwise to be universally applicable and absolute. Nevertheless, different variants of the Engineering Method are used successfully to create the technology, and the world.

The Engineering Method is iterative. Iterative nature is built into the method. Steps are retraced when failure occurs, in search of alternatives, or for optimization reasons.

The main distinction between craftsmanship and engineering is the systematic application of science. Crafts are developed over time usually by local knowledge. Engineering evolves more selectively, more rapidly, and by using and expanding science.

Project Approach
The concept of a project is familiar to most of us. A project is writing an essay, building a cabin, cleaning a room and so forth. Engineering a product or solving a problem is a project. In particular, a project refers to the activities (steps in the Engineering Method) and the particular outcomes (products) associated with the activities. A project is defined by others, you, or defined jointly by you and others.

Developing a product involves good project management. Many approaches and issues in Engineering Method overlap the project management approaches and issues. The Engineering Method is discussed in the context of a project; however, I will defer direct discussion about project management issues to later time.

Problem Selection

For an employee engineer the problem selection involves the identification of a need relevant to the company. Most likely she/he will be assigned a project. For a student or a hobbyist the problem selection is a more open phase. She/he would have to identify a worthy need or interest.

Preliminary Ideas
Students, hobbyists, professionals, and companies hunt for good ideas. Hunting for and evaluating ideas is a talent. Initially, the ideas are explored in breadth. Intuition, experience, and expert opinion are the guides in the exploration. During this phase, try not to be too judgmental or being too out in the fringe. The result of this phase may include a list of possible project ideas, sketches of product ideas, and collected project articles. The following are sources for project ideas.

  • Magazines
  • Internet Sites (Think Cycle, TEEDOR)
  • Technology Forecast Lists (GW Forcasts, BT List)
  • Patents: (identify an area where cluster of activity is taking place     and select a project from that area)
  • Patents: (select a project that is "not quite technically or     commercially successful" and correct by invention)
  • Brainstorming
  • Consultants
  • Own Ideas (How can I improve a situation? Would that not be     neat to do?)

Refinement and Evaluation
Not all ideas are worth pursuing. Ideas need to be considered in the particular engineering context.

Consider the available resources, time, and expertise.
Consider "needs", interests, or market demands.
Consult with potential users and clients if possible.
Consider your personal requirements and motivations.
Consult with experts if possible.
Research on vague ideas.

After careful consideration narrow down the project domain to three to five projects. Then, prioritize the project selections. Select the most promising project. When selecting the project explicitly state the reasons: "needs", commerce or amusement. Also, select a project that is challenging and manageable. Select a project that is practical, within the range of your knowledge, experience, and resources.

Feasibility Study
Assessment of Need and Interests:
The product must have a need, market demand, or interests that will provide an acceptable net benefit for the costs employed to engineer the product. To assess the need and market demand, personally interview potential clients and users, conduct market research if possible, seek expert opinion and use your personal experience; then decide.

If the project lacks sufficient demand or resources, or if the designer is not motivated, then the project needs to be modified or abandoned.

Survey Existing Systems and State of the Art:
Usually, there will exist products similar to the product that you select to engineer. Research and study the existing systems and the state of the art systems similar to the one that you are proposing. The challenge is to out compete, offer an alternative product, or find a niche market for your product thorough engineering. Use your experience and consult expert opinion to decide whether you can engineer to create a superior or niche or unique product. If not modify or abandon the project now.

Preliminary technical feasibility:
Is the product producible?
There are obvious impossible ideas or projects such as perpetual machines and automobiles from scratch.

If feasibility study indicates that product in its entire scope is technically feasible, has a market demand, and if you assess that you can deliver within budget and on time, then write the Request for Design. . Otherwise modify the project and reevaluate it, select another project, or start all over again.

Request for Design
In the Request for Design define the product that you are proposing to design. Illustrate the need, market demand, or the interest for the product. Detail the objectives of the project. Illustrate how you are suited to design the product. Also, note the risks involved in undertaking the project.

If your supervisor rejects the Request for Design, then you will have to modify the project, select another project, or start all over again.

At the end of the Problem Selection phase you must have a product idea that has a demand, doable, and that you are excited about.

Requirement Analysis

User and Client Requirements
A distinction is made between the client (the company, the supervisor, or instructor) and the actual user. The user's wishes and the client's requirements are not necessarily the same. Generally, the engineer is constrained by the client's requirements and she/he strives to meet the user's needs, particularly in terms of safety.

User and client needs were considered during the problem selection. At this stage more details and analysis are sought. Thus, identify, collect, organize, clarify, and prioritize the client and user requirements. What are the methods to establish the client and user requirements?

  • Personal interviews
  • Questionnaires
  • Market research
  • Use case scenarios
  • Analysis of user's requirements of similar products
  • Literature review

Establish the Level of Design
From the Request for Design the level at which the solution may lie should become apparent. Neigel Cross illustrates the importance of establishing the level of design by noting the classic problem 'to design a doorknob' (pg77). If the designer designs a door with a doorknob, the client who sells doorknobs would have no use for the door. If the designer finds a solution which does not need a doorknob, the client has no interest at all. If the designer designs "latch mechanisms" and no doorknob, again the client is not served. Thus, determining and agreeing on the level and scope of the design is an important step in the Engineering Method.

Determine the Performance Requirements
The information provided by clients and user are usually not in the technical language. Convert the user and client requirements into technical form; be precise as possible.

Functional requirements - What is the system supposed to do?
Non-functional requirements or Constraints (i.e: use certain     hardware, physical look, human factors )
Operational requirements

As noted before, engineering problems are ill defined. Thus, in order to clarify the user and client requirements the engineer may need to consider particular solutions. However, I defer considering solutions until the next phase-conceptual design.

Specifications Document
Review the objectives of the project. State and justify the established level of design. Also, list quantifiable performance requirements which when delivered would deem the product a success.

A more detailed and more comprehensive technical description (perhaps consisting of block diagrams, flow charts, sketches, graphics, power supplies, housing, interface mock-ups) of what you are going to achieve will be provided after the conceptual design. Further note that the conceptual design phase may take place parallel to requirement analysis.

The Specification Document is the operational definition of success. Thus, communicate the specifications with the client and reach an agreement.

Conceptual Design

Given the Specifications Document, how does an engineer generate solutions? The process is neither automatic nor unguided. Engineering does not take place in a vacuum. An engineer is assigned or undertakes a project that lies within his/her expertise, resources, time and social domain. The engineering solution should lie within the domain. The task of the engineer is to imagine, draw, adapt, copy, modify, improve and synthesize in order to actualize a solution.

System Study
The purpose of the study is to explore, identify and establish key system concepts.

The system can be decomposed at high levels (The Core Design, Component Systems, Input and Output Peripherals, Housing, Interconnections and Interfaces) and analyzed.

The design of existing systems and state of the art should be studied. Suitable design components that can be adopted legally, easily, and cost effectively to meet the system needs should be noted.

Research (colleges, experts, Internet, books, and journals) should be conducted if necessary.

System Design
Various design possibilities should be generated, considered and evaluated. The decisions made at this stage will shape the overall design a great deal. If the workability of certain concepts are in doubt, more research should be conducted. Again, expert opinion can assist wielding out fringe concepts and in assessing the degree of difficulty in developing certain components. Also, consider the economic and produciability factors of the system design. Research, experience, and expert opinion should help in deciding upon a suitable system design. At the end of this phase the concepts that are to be utilized must be firmly established, and the system design completed.

End Product Visualization Document
After the system design the engineer must have a clear vision as to what product she/he will deliver. Imagine that the product is complete, and it functions according to the concepts that were developed. Then, create drawings, scenarios, and other documents visualizing the product in use and being a success. This process helps in reviewing the objectives and concepts, and motivates the designer.

Refinement of the System Design
Hardware Description

  • system level design (core design, and component designs)
  • block diagrams
  • select the hardware platform
  • power supply requirements

Software Description

  • high level flow chart
  • identify languages
  • sketch screen shots

Interconnection and Interfacing

  • internal connections
  • identify other systems with which the system must interact
  • mock up interfaces


  • draw the physical appearance of the system

System Design Documents
The system design documents are the refined hardware and software descriptions, and the interconnection and interfacing and casing designs.

System Design Assessment and Specifications Update
Assess whether the system meets the specifications. Add further details to the specifications. Due to the ill-defined nature of engineering problems it is likely that specifications may need to be altered. Communicate the new specifications to the client and forge an agreement.

The End Product Visualization Document and the Specifications Document together define the Operational Definition of Success for the client, user, and the engineer.

If the specifications cannot be met, or a new agreement cannot be met, then modify the system design or the original specifications.

Detail Design

The engineering product becomes alive in its detail. The "messy details" engages the engineer, and at times drowns her/him. Important, trivial, and tedious details must be attended in order to actualize the concepts.

Design Development
The concepts finalized at the system design need to be developed, detailed and integrated. Prioritize all the concepts; then develop and design according to the priority. Knowing that proven and strong concepts will work does not guarantee that the engineer will be able develop and design them to work within given resources and time constraints. Also, allocating sufficient time and resources to develop and detail the weak concepts is important. Moreover, detail design involves testing most if not all the assumptions made at the conceptual phase.

Design issues bundle like a snowball, or arrive like Russian dolls. The type of design issues, and issue management requires lengthy discussions, which I avoid at this point. Economic, manufacturing, technical, and maintenance factors are considered during the design. The design must seek to optimize for available knowledge and skills, cost, as well as for functionality. However, if functional requirements are proving difficult to meet, then the issue of optimization should be of less or no priority. On the other hand, if functional requirements are being confidently met, then the issue of optimization is prominent. Moreover, ensure that the selected components are available.

Design development is a non-linear process. Certain minor concepts sometimes consume enormous time and resources, while some important concepts lend themselves to quick detail design. The detail design requires maturity and patient work from the engineer.

Detailed Design Documents
Hardware Description

  • Circuit design for core and component systems
  • Parts selection
  • Power supply selection

Software Design

  • Detail flow chart
  • Data flow analysis
  • Objects identification and design

Interface Design
Housing Design

Design Assessment
Design assessment takes place throughout the development and design phase. The focus is to assess whether the design will deliver. Simulations, facts check up, numerical calculations, and assumption testing are all ways of assessing the design. If the design does not meet the specifications, then the design or the specifications need to be modified.

Freezing the Design
After arriving at a detailed and comprehensive design, consult with the client or the supervisor, and FREEZE the design. Freezing the design is a critical step in the design process, which should never be overlooked.

If the detailed design is frozen then implementation can begin, otherwise, return to the conceptual design or modify the detailed design.

Testing, Quality Assurance & Evaluation

Testing, verifying, demonstrating, and evaluating takes place during the entire engineering process. Those activities are part of the Testing and Evaluation stage, even though this stage is listed in the final stages of the Engineering Method. Developing proper tests, testing, analysis and reporting differ depending on the engineering contexts.



Documents are used to manage and document the engineering process. In fact, documents are the result of the engineering activity. Sketches, drawings, block diagrams, schematic diagrams, flow charts, simulations, experimental data, specifications, reports, manuals are results of the engineering activity. Also, contracts, gantt charts, milestone schedules, status reports, and minutes are important to manage and document the engineering process. Ideas in the head manifest thorough documentation. Failing to document properly is to negate the engineering process and the results all together.

The Product Report
Documentation takes place throughout the process. At the last stage, usually a report is prepared bringing together all the elements such as requirements, specifications, design documents, testing and evaluation results, manuals, and post mortem analysis. The report is an integral part of the project.


Nigel Cross. Engineering Design Methods: Strategies for Product Design. 2nd ed.
Toronto: John Wiley & Sons, 1994.

Martyn S. Ray. Elements of Engineering Design.
Toronto: Prentice Hall, 1985.

Peter D. Hiscoks. Random Thoughts on Electronic Project Managment: Design, Construction and Debugging.
Toronto: Ryerson University, 2002.

Jasbir S. Arora. Introduction to Optimum Design.
Toronto: McGraw Hill, 1989.

John W. Priest. Engineering Design for Producibility and Reliability.
New York: Marcel Dekker, 1988.

Paul T. Durbin eds. Critical Perspective on Nonacademic Science and Engineering.

Michael D. Rychener. Expert Systems for Engineering Design
Toronto: Academic, 1988.


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