nnmishra wrote:Morphology of Design
What is Design?
Engineering design is not an art or skill : it is a cognitive or intellectual process based on knowledge---- by John R. Dixon.
Engineering design is an iterative decision-making and problem solving activity to produce the plan to convert resoures optimally into systems or devices to fulfill a specified task. In case of machine design, the resources are material , machines and wquipments involved, and labour put into, and system is the machine product.
The activity is subjected to certain constraints. Those are (1) Problem-solving constraints, designer's problem-solving capabilities, time available, laboratory or computational facilities, and (2) the problem-solution constrains, cost of the product, availability of raw materials , equipments or manufacturing facilities.
Plan is a method, or scheme of actions , or a way proposed.
“Design is that area of human experience, skill and knowledge which is concerned with man’s ability to mould his environment to suit his material and spiritual needs.”
Design is essentially a rational, logical, sequential process intended to solve problems or “initiate change in man-made things”
For the term “design process,” we can also read “problem-solving process”, which in all but its abstract forms works by consultation and consensus.
The process begins with the identification and analysis of a problem or need and proceeds through a structured sequence in which information is researched and ideas explored and evaluated until the optimum solution to the problem or need is devised.
Design was not a total process. The work of participants in the process was often compartmentalised, each having little if any input in matters which fell outside the boundaries of their specific expertise. Thus, participants explored their ideas unilaterally, with one or another participant, through virtue of their “expertise”, imposing constraints upon all others.
Morphology of Design:
Morphology, the study of pattern and form, is crucial to design because it constitutes an essential part of its corpus of coherent knowledge.
The collection of time phases of the followiing steps is usually called the "Morphology of Design"
The phases are:
(1) Feasability study (evaluation of alternatives): The aim is to produce a number of feasible and useful solutions.
The Design Process
In Design Process, we will have to look at techniques or best practices, that help the egineer design quality products. To understand how to make the best use of the techniques, it is omportant to look at them in the context of the overall design process. Thus, the progress of a product from need to production is explored by means of examples that demonstrate the flexibility of the process. The emphasis is on the importence of design documentaion. A design problem is introduced and is used as acase study.
Overview of the Design Process
The Design process varies from product to product and industry to indistry. Nonethless, we can construct a generic diagram of the activities that must be accomplished for all projects.
Before the design of a product can begin, the need for that prodict must be established. There are two sources for design projects, the market or the development of a new product idea without market demand. About 80 percent of new product development is market-driven. Without a custumer for the product, there is no way to recover the costes of design and manufacture. Thus, the most important part inlunderstanding tyhe design problem lies in assessing the market , that is , establishing what the custumer wants in the product. Even if market-driven, new products must contain the latest technology if they are to be perceived as being of high quality for what consumers means by "high quality"
Product Design Specifications
1. What is a PDS and why write one?
A product design specification (PDS) is a document which sets out fully and in detail exactly what will be required of a product, before it is designed. Many companies do not work to such formal specifications , but as a result they are not fully in control of what they produce. PDSs are essential.
A PDS does not just help the people who design and make the product. Those who eventually use it also benefit. Consumers' judgements are all too often overlooked by engineers, but people think critically about the products they buy. They may take an interest in design or engineering for its own sake. They certainly will not hesitate to criticise a product if it does not do, efficiently and reliably, what they expect it to. A PDS is therefore also an analysis of what the market will demand of the product.
2. Before you write a PDS
A PDS specifies a problem, not a solution. A PDS does not pre-empt the design process by predicting its outcome. Rather, it defines the task by listing all the conditions the product will have to meet. This can involve a good deal of research, into market conditions, competing products, and the relevant literature including patents.
When you write a PDS, you are defining something that does not yet exist. But for practice at thinking this way, it can help to look at an existing product and work out what its PDS was
3. Everybody is involved
Once a PDS has been written, it becomes the principal reference for all those working on the design. The PDS must therefore be written in language that all parties can understand.
A PDS must not become the exclusive property of one group. Everybody concerned with the project must endorse the PDS and share responsibility for observing it.
4. A PDS can change
A PDS has to be a written document, but it does not need to be engraved in stone. It can be changed. As a rule, the design follows the PDS. But if the emerging design departs from the PDS for some good reason, the PDS can be revised to accommodate the change. The important thing is to keep the PDS and the design in correspondence throughout the design process. In this way, the PDS ends up specifying not just the design, but the product itself.
5. Points to cover in a PDS
This section give detailed advice on writing a PDS under the 29 headings listed below. It is therefore a good idea to write your PDS under these headings, leaving out only those that clearly do not apply.
22 Industry standards
3 Target production cost
23 Shelf life / storage life
5 Manufacturing facilities
15 Special processes
6 Product life span
27 Market constraints
28 Political and social factors
9 Service life
19 Quality and reliability
29 Design time
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