divyachristopher.files.wordpress.com€¦ · web viewengineering is the process of turning...

Module 1 Design and Engineering Notes

Defining a Design Process-:

The design process is a sequence of events and a set of guidelines that helps define a clear starting point that takes the designer from visualizing a product in his/her imagination to realizing it in real life in a systematic manner—without hindering the creative process. The design of a device or system can be done in one of two ways:

1. Evolutionary change: A product is allowed to evolve over a period of time with only slight improvement.

2. Innovation: The creative skills and analytical ability of the design engineer play an important role in rapid scientific growth and technological discoveries.

Introduction to Design and Engineering Design

Design is conceiving and giving form to artifacts (man-made objects) that solves problems in meeting users needs.

Conceiving in this context means imagining, visualizing a solution to a problem or need.

Form means shape, physical appearance, formulation or a procedure.

Artifacts– standard definition: Artificial man-made objects produced or shaped by human craft, especially a tool, weapon or ornament of archaeological or historical interest. Artifacts in design could be a product, software, building, dress, a process, a dam, graphics etc.

Examples: Architectural Design; Building Design; Interior Design; Fashion Design; Lighting Design; Software Design; Product Design; Engineering Design; Automobile Design; Machine Design; Web Design; Logo Design- to name a few.

Engineering is the process of turning abstract ideas into physical representations. This creative art is called design. Primary aim of Engineering is to design and realize a product, system or process, to satisfy users needs. Engineering design participants are client, designer and user.

User - He is the person who uses the product/system which is being designed.

Client – He is a person / company that wants a design for his product. 2 types of clients: - i) internal client (e.g. person working in a company) ii) External (e.g. government agency)

Designer – The person who solves the client’s problem in a way that meets the user’s and client’s needs. In addition Designer should be aware of professional and social ethics and values. For any Design to be taken up, there should be a need gap or a problem that needs a solution. This gap or need could be identified by the user, an observer or by an organization. Designer designs a product according to the specifications listed by the client.


Engineering design is the method that engineers use to identify and solve problems. Engineering design is purposeful. The process always begins with an explicit goal. Engineering design is “design under constraint.” Designers must choose solutions that include the most desired features and fewest negative characteristics. Engineering design is systematic and iterative. It is a process that includes steps that can be repeated, although not always in the same order. Steps include things like planning, modeling, testing, and improving designs. Engineering design is a social, collaborative enterprise. This process is often done in small teams that include people with different kinds of knowledge and experience.

Detailing Customer Requirements

The need for a new design can be generated from several sources, including the following:

• Client request: In a design company, a client may submit a request for developing an artifact. It is often unlikely that the need will be expressed clearly. The client may know only the type of product that he or she wants; for example, “I need a safe ladder.”

• Modification of an existing design: Often a client asks for a modification of an existing artifact to make it simpler and easy to use. For example, in a market search you may notice many brand names for coffee makers and the differences among them, like shape, material used, cost, or special features.

Market Analysis - Designers must locate what is already available in the market and what they have to offer. Information gathering is a vital task. Design engineers may consult the following sources to determine market availability:

• Technical and trade journals, • Abstracts, • Research reports, • Technical libraries, • Catalog of component suppliers, • U.S. Patent Office, • The Internet

Setting Design Objectives – These are the qualities the objects should have.

In this stage of the design process, the designer defines what all qualities have to be implemented to resolve the need(s). The definition is a general statement of the desired end product. The client request comes in a vague verbal statement such as, “I need an aluminum can crusher.” or “I need a safe ladder.” Designers must recognize that customer needs are not the same as product specifications. Needs should be expressed in functional terms. The designer’s function is to clarify the client’s design requirements. An objective tree may be constructed for clarification. Often the need statement and goals are combined into one process. An objective tree is a tool used by designers to organize the customer’s wants.

Objectives (or goals) are expressions of the desired attribute and behaviours that the client wants to see in the product or process. Objectives are the qualities the object should have. Clients tend to speak in terms of objectives. A 3-step procedure can be evolved for objective preparation:

1) Prepare a list of design objectives from the customer through an interview or interaction

a) Identify user requirements

b) Identify various alternatives of design

c) Stick to time schedule


d) Reduce the cost of design

e) Simple to operate components

f) Ergonomics and safety to be considered

g) Nature friendly design

2) Order the list into sets of higher-level and lower-level objectives

3) Draw the objective tree, showing hierarchical relationships and interconnections.

Identifying Design Constraints

A limit/restriction on the features/ behavior of the design. A proposed design is unacceptable, if these limits are isolated. They could be on some of the features or attributes of the design. Constraint is a restriction on design, in many fronts. They could be on some of the features or attributes of the design. Can a design work at high temperature? Can the product be portable? Does it meet the environmental regulations?

Design constraints are classified under the following headings: 1. Functional 2. Safety 3. Ergonomics 4. Production 5. Quality Control 6. Assembly 7. Transport 8. Operation 9. Maintenance

1. Functional constraints- Imposes limit on functional aspects of the product to be designed. a) Overall Geometry (size, width, space) , b) Motion of parts – (Type, Direction, velocity, acceleration) , c) Forces involved – (direction, magnitude, load) , d) Energy needed – (heating, cooling, pressure) , e) Materials to be used – (flow, transport, properties), f) Control system – (electrical, hydraulic, mechanical) , g) Information flow-inputs, outputs, form

2. Safety constraints – Constraint that specifies a specific safeguard. a) Operational – direct, indirect, hazard elimination , b) Human – warnings, trainings, c) Environmental – land, sea, air, noise, light, radiation, transport.

3. Quality constraints – Those constraints posed in the delivery of the final product. a) Quality Assurance – regulations, standards b) Quality Control – inspection, testing, labeling c) Reliability – design life, failures, statistics

4. Manufacturing constraints – These include limitations imposed during manufacturing and production of product due to lack of machinery a) Purchase of components – reliability, quality control , inspection b) Assembly – installation, bolting, welding c) Transport – material handling, clearance, packaging.

5. Timing constraints – Time it refers to the actual time required to complete a product deliverable. a) Design schedule – project planning, project control b) Development schedule – design detailing c) Production schedule – manufacture, assembly, packing, transport, d) Delivery schedule – delivery date.

6. Economic constraints – These are limits on production costs and operating costs. a) Marketing analysis – size of market, distribution, b) Design costs – design team computing, c) Development costs – design detailing, testing costs , d) Manufacturing costs – tooling, labour, overhead, assembly, inspection, e)


Distribution costs – packaging, transport, spare parts, warranty, f) Resources – time, budget, capital, machines, material, labour.

7. Ergonomic constraints – a) Ergonomic design – man-machine relationships

8. Ecological constraints – Moisture limits, dust levels that are directly related to the environment a) Environmental impact on natural resources, b) sustainability on technological innovation – implications for generations

9. Aesthetic constraints – It deals with the nature of art, beauty and taste. a) Customer appeal – shape, color, texture, b) Fashion – culture, history, c) Future expectations – rate of change in technology

10. Life-cycle constraints – a) Distribution – means of transport, rules, regulations b) operation – working environment c) Maintenenace – repair, diagnostics d) Disposal – recycle, scrap.

11. Legal / ethical constraints – Constraints such as governmental safety requirements, a) Regulations b) Ethics – public safety, health, welfare and integrity c) Intellectual property – patents , trademarks, copyrights.

Establishing Functions

There are 5 broad classifications for an engineering design function:

1. Research function – It involves identifying need for the product, defining the working principle, collection of data required for processes.

2. Engineering functions – It mainly covers the product design aspects. This stage is directly responsible for technical functioning of the product

3. Manufacturing functions – It decides the method of production, determination of tools, cost controlling methods, purchase raw materials , etc.

4. Quality control functions – It involves quality control of products as per the design, safety considerations, dimensional accuracy, working perfection etc.

5. Commercial functions – It deals with the cost and service related aspects of a process. It includes relationship with clients marketing, sales, logistics, warehousing, human resources, etc.

Procedure to establish functional structure

Express overall functions into inputs and outputs

Break down overall functions into a set of essential sub functions


Draw the block diagram showing interactions between sub functions. When drawing this, decide how sub functions are linked. Different grades of design are indicated by types of lines. Say thin continuous line, dashed line, chain line, and continuous thick line. Draw system boundary, Search for appropriate components for performing each sub functions and its interactions.

Domestic washing machine – to remove stain from clothes

Sub functions

Generating Design Alternatives

The process of generating alternative solutions to the stated goal in the form of concepts requires creative ability. The conceptualization starts with generating new ideas. In this stage, the designer must review the market analysis and the task specifications as he or she engages in the process of innovation and creativity. The alternatives do not need to be worked out in detail but are recorded as possibilities to be tested. Alternatives to perform the functions should be listed in an organized fashion. For example, to design a novel transportation system, a designer may list the methods as follows.

1. Natural way


a. Human

i. Walk

ii. Swim

b. Animal

i. Ride

ii. Pulled in a cart

2. With aids

a. Land

i. Bike

ii. Skate

b. Water

i. Canoe

ii. Tube

c. Air

i. Kite

d. Mechanical

i. Land

• Car

• Train

• Tube

ii. Water

• Ship

iii. Air

• Plane

• Rocket


Choosing a Design

Once a number of concepts have been generated in sufficient detail, a decision must be made about which one or ones will enter the next, most expensive, stages of the design process. An excellent technique to guide the designer in making the best decision regarding these alternatives is a scoring matrix, which forces a more penetrating study of each alternative against specified criteria.

“Students need an easy way to take their books to school”. Now there is the need to define this problem a bit more in detail. Who are the students? What is meant by easy?

Make the problem definition as best as possible. Identify the Product attributes/functions and assign weightages.

Formatting the Objective Tree

Pairwise Comparison Chart (PCC) - It is a tool for ordering the relative importance of objectives. It is based on the assumption that we can order any 2 objectives taken as a pair. PCC is a simple matrix that allows us to a) compare each and every objective with each remaining objective individually b) add total scores for each objective. The scores for each objective are found by adding across each row. The objective with score 0 can be considered as least important; but we cannot drop objectives that scores zeros.

E.g. We prefer Easy to carry – Safe to Carry, Safe to Carry – Healthy to Carry, Healthy to Carry – Easy to carry, Safe to carry

Easy to carry > Healthy to Carry > Safe to Carry > Easy to make > Attractive

Cost analysis (Engineering Economy and Cost Analysis) Cost estimation plays an important role in the product development cycle. Proper cost estimation will simplify the process to determine the profit that will be obtained, and to simplify investment of a new tool.


COST ACCOUNTING - It is a branch of accountancy which records and analyses the cost structure of a business concern solely with the purpose of its measurement and control.

Objectives-

To determine actual cost of a product or the process.

To compare the actual cost with the estimated cost.

To provide the management with actual cost figures so that it can frame practical sales policies and cost structure etc.

To ascertain departmental efficiency on the basis of a actual cost it incurs for production

To determine profitability of products.

The cost can be divided into two broad categories – direct and indirect cost

Material cost: Material cost can be sub-divided into

Direct material cost : The material which goes into the product and becomes a part of the product is direct material. Its cost is called direct material cost.

e.g. A fountain pen has many parts. All materials required for all the parts of a pen is direct material.

Indirect material cost : There are certain materials or tools and equipments which are required for production but they do not form a part of the product (or component) they only assist in production. Such as cutting tools, special holding and fixing device's, certain formed tools, fuels, rejected materials grease, cutting fluid etc. Their costs are called indirect material cost.

LABOUR COST: Labour cost can be subdivided into

Direct labour cost : The labour which is directly involved for production is direct labour and its cost is direct labour cost. So a lathe operator who machines a job or a grinder who grinds a job is direct involved.

Indirect labour cost : The indirect labour cost is the cost of labours who are not working for a particular job but are responsible (and help) for the production of all jobs manufactured by the industry. The foreman or charge man helps the production indirectly.

Other expenses can be subdivided into :

Direct expenses : Direct expenses are those which could be attributed to particular product or group of products.

e.g. cost of design and drawings, cost of special layouts, cost of hiring special machine tool, cutting tools etc. for doing some specific operations, cost of catalogue and price list.


Indirect expenses : These expenses are incurred overall running and production of the whole industry, so these cannot be attributed to a particular job. e.g. advertisement expenses, telephone bill, rent.

Indirect costs are more popularly called overhead cost. The overhead could be on the following accounts :

Manufacturing overhead : It includes, all expenses connected with manufacture of the product. Such as, shop inspectors, maintenance cast

Administrative overhead : It includes expenses incurred on administrative section such as — salary and wages of clerk.

Sales and advertisement expenses : These are those incurred , rent of sales office and other expenses on this office, service after sale etc.

Distribution overheads : These are warehouse charges, loading and unloading charges.

Research and design overheads : These are expenses incurred for research and development purposes.

Classification of indirect cost.

Variable cost. It may vary if production volume is increased or new processes are introduced. Because it may need more electricity, more supervisors, opening of new plants etc.

Non-variable cost : If overhead cost does not increase, even if production volume is increased, it is called non-variable overhead. It can happen if the increase is not much or there were over staffing, unutilised space, equipment’s etc.

Semi-variable cost: The overhead may vary (increase) to some extent for certain volume increase and further increase in volume does not increase the overhead.

Selling price-

Prime cost = direct labour + direct material + other direct expenses

Factory overhead = Indirect labour + indirect material + other indirect expenses

Manufacturing cost (or factory cost) = prime cost + works overhead (or factory overhead)

Production cost = manufacturing cost + administrative cost

Establishment cost = sales + distribution and advertisement

Total cost = production cost + establishment cost


Selling price = Total cost + profit

Standard Cost of products.

Standard cost = standard cost of material + standard labour cost (for doing the job in standard time) + standard overhead.

Aesthetics

Aesthetics is the human perception of beauty, including sight, sound, smell, touch, taste, and movement – not just visual appeal.

Aesthetics is the aspect of design and technology which most closely relates to art and design, and issues of colour, shape, texture, contrast, form, balance, cultural references and emotional response are common to both areas.

It is concerned with study of appreciation of beauty.

Some concepts of aesthetics in Engineering are :

-Function :Aesthetics underlines form description of actual operative function of the product.

-Form : it comprises elements like line , proportion, colour and texture…

-Unity with the help of similar proportions and shapes

-Styling refers to decoration and ornamentation.


Product Styling and EleganceHere the form is the focus in the design. The same function can be met through different formsSome countries are well known for stylish designs. It has more to do with art than engineering.Product of personal use need styling and elegance. Automobiles, Watches, Mobiles, etc.Industrial designers do styling design. Elegance is not about styling. It is about the ability of the design to stand out among its competitors. While styling counts, many subtle features of the design contributes to its elegance.Style and Elegance

Ergonomics

Sometimes named - Human factors engineering.

This area is concerned with human well-being while using the design.

Examples are many in this area. Driving cars, Using Laptops, Operating Machines etc.

It is a science which deals with systematic study of the relationship and interaction between man, machine and working environment. Main objective is to ensure that human needs for safe and efficient working are met at workplace.

Value Analysis


Value analysis or value engineering is a technique used to identify and remove unnecessary cost – without compromising quality and reliability. The value engineering is a customer oriented approach to entire design process.

Main target: find value of each feature or a component along with the cost

Value = worth of component

Cost of same

The steps focusing the features of component use the value formula:

-Ensure all the functions of a component

-Identify life cycle cost of the component

-Identify the worth of function to the customer

-Compare worth to the cost to identify feature that have low relative value

Value Engineering

Value Engineering is the study of functions to satisfy the user needs of a quality product at low life cycle cost through well planned design with creativity. Aims at Value addition in design. Value can be enhanced through better performance and cost reduction. Adding features that enhances the value of the product with marginal increase in cost. Examples:- Reduction of parts


during design, introduction of simple design modifications that could assist in manufacture or assembly. Choosing materials that can replace costly ones and improve the performance.

Value Equation: V= P/C where V- Value, P- Performance and C – Cost

Poor Value results from:-

-Poor collaboration within the design group

-Badly conceived design objectives

-Wrong assumptions based on poor information

-Fixation with previous design concepts

-Failure to assess the challenge in design

Value Engineering questions:

What the product is supposed to do?

What else can it do?

What else is needed to enhance the value?

Will these secondary functions add value ?

What are the value added feature you notice in a stapler?

Can one think of any additional functions that can add value to it?


The enhancement a company gives its product or service before offering the product to customers.

Addition of values can either increase the product's price or value. For example, offering one year of free support on a new computer would be a value-added feature. Coconut products sale in INDIA would add value in engineering and marketing… Think of value addition to the following:- 1) Laser printer 2) Ladder 3) Jacket for winter

Concurrent Engineering

Concurrent engineering, also known as simultaneous engineering, is a method of designing and developing products, in which the different stages run simultaneously. Serial operations are done in parallel, rather than consecutively. It decreases product development time and also the time to market, leading to improved productivity and reduced costs. This is possible using IT. Saves cost and time. This has a lot of relevance to Design. IT has allowed this to happen as the evolving designs are seen by all concerned.

Reverse Engineering - A nice modern term for copying a design. How to reverse engineer?

Manual, Computer Assisted, One can digitize any product and create its CAD model.

This model can now be easily modified to create new designs of the same product.

An existing product can be redesigned through reverse engineering.

Fringe Projection – method of digitization

Products are digitized and designs are revealed. The design can be modified using the digital data.

Good for making spare parts that are not available. Modify an existing design.

divyachristopher.files.wordpress.com€¦ · web viewengineering is the process of turning...

Documents