PRODUCT DESIGN

Ergonomics

Ergonomics is the human factor in engineering. It is the study of how people interact with machines. Most products have to work with people in some manner. People occupy a space in or around the design, and they may provide a source of power or control or act as a sensor for the design. For example, people sense if an automobile air-conditioning system is maintaining a comfortable temperature inside the car. These factors form the basis for human factors, or ergonomics, of a design.

A design solution can be considered successful if the design fits the people using it. The handle of a power tool must fit the hand of everybody using it. The tool must not be too heavy or cumbersome to be manipulated by all sizes of people using the tool. The geometric properties of people-their weight, height, reach, circumference, and so on-are called anthropometric data. The difficulty in designing for ergonomics is the abundance of anthropometric data. The military has collected and evaluated the distribution of human beings and published this information in military standard tables. A successful design needs to be evaluated and analyzed against the distribution of geometry of the people using it. The following Figure shows the geometry of typical adult males and females for the general population in millimeters. Since people come in different sizes and shapes, such data are used by design engineers to assure that their design fits the user.

A good design will be adjustable enough to fit 95 percent of the people who will use it.

ENGINEERING DESIGN PROCESS

Education Transfer Plan

Prepared by

Seyyed Khandani, Ph.D.

for STEP BY STEP GUIDE unigraphics simple tutorial please visit.........

www.unigraphicsimpletutorial.blogspot.com

---or---

www.unigraphic-simple-tutorial.com

Functional analysis.

This part determines whether the given design solution will function the way it should. Functional analysis is fundamental to the evaluation and success of all designs. A design solution that does not function properly is a failure even if it meets all other criteria. Consider for example the invention of the ballpoint pen. This common instrument was first invented and manufactured during World War II. The ballpoint pen was supposed to solve the problems of refilling and messiness inherent to the fountain pen. Unfortunately, this new design had never been evaluated for functionality. The early pens depended on gravity for the ink to flow to the roller ball.

This meant that the pens only worked in a vertical upright position, and the ink flow was inconsistent: Sometimes it flowed too heavily, leaving smudgy blotches on the paper; other times the flow was too light and the markings were unreadable. The first ballpoint pens tended to leak around the ball, ruining people's clothes. An elastic ink developed in 1949, allowed the ink to flow over the ball through smooth capillary action. Not until the 1950s did the ballpoint pen finally become a practical writing instrument, thanks to proper ink and engineering. Economy, appearance, durability, and marketability of a design are unimportant if the product does not function properly.

ENGINEERING DESIGN PROCESS

Education Transfer Plan

Prepared by

Seyyed Khandani, Ph.D.

for STEP BY STEP GUIDE autocad simple tutorial please visit.........

www.autocadsimpletutorial.blogspot.com

---or---

www.autocad-simple-tutorial.com

GATHER PERTINENT INFORMATION

Before you can go further in the design process, you need to collect all the information available that relates to the problem. Novice designers will quickly skip over this step and proceed to the generation of alternative solutions. You will find, however, that effortspent searching for information about your problem will pay big dividends later in the design process. Gathering pertinent information can reveal facts about the problem that result in a redefinition of the problem. You may discover mistakes and false starts made by other designers. Information gathering for most design problems begins with asking the following questions. If the problem addresses a need that is new, then there are no existing solutions to the problems, so obviously some of the questions would not be asked.

· Is the problem real and its statement accurate?

· Is there really a need for a new solution or has the problem already been solved?

· What are the existing solutions to the problem?

· What is wrong with the way the problem is currently being solved?

· What is right about the way the problem is currently being solved?

· What companies manufacture the existing solution to the problem?

· What are the economic factors governing the solution?

· How much will people pay for a solution to the problem?

· What other factors are important to the problem solution (such as safety,

aesthetics and environmental issues)?

ENGINEERING DESIGN PROCESS

Education Transfer Plan

Prepared by

Seyyed Khandani, Ph.D.

skhandani@dvc.edu

for STEP BY STEP GUIDE unigraphics simple tutorial please visit.........

www.unigraphicsimpletutorial.blogspot.com

---or---

www.unigraphic-simple-tutorial.com

Develop a Problem Statement

The first step in the problem-solving process, therefore, is to formulate the problem in clear and unambiguous terms. Defining the problem is not the same as recognizing a need.

The problem definition statement results from first identifying a need. The engineer at the

airbag company responded to a need to reduce the number of airbag inflation failures. He

made a mistake, however, in not formulating a clear definition of the problem before generating a solution. Once a need has been established, engineers define that need in

terms of an engineering design problem statement. To reach a clear definition, they collect data, run experiments, and perform computations that allow that need to be expressed as part of an engineering problem-solving process.

Consider for example the statement "Design a better mousetrap." This statement is not an adequate problem definition for an engineering design problem. It expresses a vague dissatisfaction with existing mousetraps and therefore establishes a need. An engineer would take this statement of need and conduct further research to identify what was lacking in existing mousetrap designs. After further investigation the engineer may discover that existing mousetraps are inadequate because they don't provide protection from the deadly Hantavirus carried by mice. Therefore, a better mousetrap may be one that is sanitary and does not expose human beings to the Hantavirus. From this need, the problem definition is modified to read, "Design a mousetrap that allows for the sanitary disposal of the trapped mouse, minimizing human exposure to the Hantavirus."

The problem statement should specifically address the real need yet be broad enough not to preclude certain solutions. A broad definition of the problem allows you to look at a wide range of alternative solutions before you focus on a specific solution. The temptation at this point in the design process is to develop a preconceived mental "picture" of the problem solution. For example, you could define the better mousetrap

problem as "Design a mousetrap that sprays the trapped mouse with disinfectant." This statement is clear and specific, but it is also too narrow. It excludes many potentially innovative solutions. If you focus on a specific picture or idea for solving the problem at this stage of the design process, you may never discover the truly innovative solutions to the problem. A problem statement should be concise and flexible enough to allow for

creative solutions.

Here is one possible problem definition statement for our better mousetrap problem:

A Better Mousetrap: Certain rodents such as the common mouse are carriers and transmitters of an often fatal virus, the Hantavirus. Conventional mousetraps expose people to this virus as they handle the trap and dispose of the mouse. Design a mousetrap that allows a person to trap and dispose of a mouse without being exposed to any bacterial or viral agents being carried on the mouse.

ENGINEERING DESIGN PROCESS

Education Transfer Plan

Prepared by

Seyyed Khandani, Ph.D.

skhandani@dvc.edu

for STEP BY STEP GUIDE photoshop simple tutorial please visit.........

www.photoshopsimpletutorial.blogspot.com

---or---