Introduction of Material And Manufacturing

IDT 203

Week 1

MANUFACTURING

•According to DeGarmo, (1997) basically, manufacturing is a ‘value adding’ activity, where the conversion of materials into products adds value to the original material.

•According to Magrab, E.B, (1997) manufacturing is interrelated activities involving product and process design, material selection, planning, production and quality assurance

Definition :

Interrelated factors in manufacturing

• Material

• Men

• Methods

• Equipment

They are to be combined properly to achieve low cost,

superior quality and on time delivery.

The Economic Importance Of Manufacturing

Wealth, in this world, springs essentially from one these three sources :

1. What is removed from the ground;

example : minerals, metals and oil

2. What is grown from the ground

example : foods; including grains, fruits and vegetable, nonfood; such as cotton, lumber and natural rubber

3. What is manufactured

Manufacturing costBasically, manufacturing cost consists :

• Material cost

• Indirect cost

• General administration costs in additional to labour cost

Normally manufacturing cost is the largest cost in the selling price. It is estimate that 40% of the selling price of a product.

Parts and material, 50%

Manufacturing costSelling price

Marketing, sales general administrative cost 25%

Profit 20%

Indirect labour 26%

Direct labour 12%

Plant and machinery depreciation, energy 12%

Engineering cost 15%

Manufacturing cost 40%

Designing in relation to manufacturing (competitiveness)

There are various approaches in enhancing the competitiveness

of the product. Example: JIS, DFM (design for manufacturability)

etc.

Design for manufacturability (DFM)

Definitions :

• According to James G. Bralla , (1996) in the broadest sense DFM is

any step, method or system that provides a product design that eases

the task of manufacturing and lower manufacturing cost.

• According to Boothroyd , G (2002) DFMA means the design of product

for ease of manufacturing and assembly .

To add value in the most efficient manner using the LEAST

AMOUNT of:

TIME

MATERIAL MANPOWER

EQUIPMENT&SPACE

Objective Of Manufacturer

The Advantages of Applying DFM during Product Design

Reduced time to market

Cost reduction

Improved quality

Reduced Time To Market

Greater Market Share

Price Premiums

Quick Reaction to Competition

Set Industry Standard

Impact of Speed To Market

Some Benefits of :

Cost reduction

Affordability of the consumer /

user

Increase Market ShareProfit Margin

The Benefits of :

Improve quality

Design SimplificationRedundant

Components

Over Design

Some DFM Guidelines :

1. Standardize.

2. Design parts that can tangle with themselves.

3. Reduce the overall number of components.

4. Reduce the number and types of part.

5. Design with symmetric features

6. Reduce Adjustments

7. Maximize Compliance

8. Eliminate machining Operations

Some DFM Guidelines :• Reduce the Overall number of component

Some DFM Guidelines :• Maximize Compliance

Some DFM Guidelines :• Reduce the number and types of parts

Some DFM Guidelines :• Reduce the number and types of parts

Some DFM Guidelines :• Provide for self-adjustment

Some DFM Guidelines :• Design with symmetric features

Some DFM Guidelines :• Design parts that can’t tangle with

themselves

Conclusion

‘Model T of 1900s’ set out by Henry Ford to cater specifically for a mass-marketSet out to produce it as cheap as possible: mass-production, inter changeable parts, moving assembly lineAn increasing the production volume and decreasing unit costIn 1910, 20,000 Model T manufactured at the cost of US $ 850 eachIn 1916, 600,000 Model T manufactured at the cost of US $ 350 each

TIME LINE OF MATERIAL DEVELOPMENT

SOME IMPORTANT PROPERTIES OF MATERIALS

• HARDNESS

• TOUGHNESS

• MALLEABILITY

• DUCTILITY

• ELECTRIC CONDUCTIVITY

• THERMAL CONDUCTIVITY

• DENSITY

• ELASTICITY

• STRENGTH

Functional requirements

An obvious factor to consider when selecting a material is the

function it should perform. For example, a knife blade must

be hard, a window transparent and an aircraft light.

Some properties of materials:

HARDNESS

A material is hard if it is not easily

worn away or dented. Cutting tools

and some kitchen utensils are made

from hard materials. A simple test to

compare the hardness of different

materials can be carried out using a

centre punch. Drop the punch from the

height of 500 mm onto each sample in

turn and compare the dents. The

smaller the dent, the harder the

material.

TOUGHNESSA tough material is one that can withstand sudden shocks without breaking. (a material that breaks easily with a sudden shock is said to be brittle.) car bumpers and cycle helmets are made from tough materials. A test for comparing the toughness of different materials may be conducted using a hammer and a vice. The samples should have identical dimensions Ø6 mm x 50 mm and contain □5 mm x 3 mm notch. Each sample in turn is clamped in the vice and the raised hammer is released so that it swings under its own weight and hits the sample. The greater the angle of swing needed to break the sample, the tougher it is.

Toughness test using a swinging hammer

MALLEABILITY

A malleable material is one

that can be permanently

deformed without cracking or

tearing when it is

compressed. Malleable

materials can be hammed into

new shapes, an essential

property when making some

jewelers and decorative

products. The malleability of

different materials can be

compared using a doming

block by sinking a dome into

each sample in turn then

examining each for cracks or

tears.

Malleability test using a doming block

DUCTILITYA ductile material is one that can be permanently deformed without cracking or tearing when it is tension. Some rods and wires are made from ductile materials. A test to compare the ductility of materials can be conducted using a draw plate and a pair of tongs. The samples should have identical dimensions and are slowly pulled through the drawplate in turn until they are completely through or broken. By measuring the new length of each sample, the ductility of the materials is determined. The greater the extension of a material, the more ductile it is.

Ductility test using a draw plate and tongs

ELECTRIC CONDUCTIVITYA material is an electric conductor if

an electric current can flow through it

easily. Easily cables and the tracks on

a printed circuit board are made from

materials that are electric conductors.

Materials that do not allow an electric

current to flow through them are

called electric insulators. A sample

electric conductivity test can be

carried out on a range of materials

using a battery, a filament bulb and

two probes ( made from pieces of

wire). The probes, spaced

approximately 500 mm apart, are

placed on each material in turn. The

brighter the bulb shines, the better the

electric conductivity of material.

Electric conductivity test using an electrical circuit

ELECTRIC CONDUCTIVITYA material is a thermal conductor if heat can flow through it easily. Cooking pots and soldering iron tips are made from materials that are thermal conductors. Materials that do not conduct heat are called thermal insulators. A test for thermal conductivity can be carried out using an immersion heater, a set of thermometers and material samples of an equal size that have been predrilled. The immersion heater is inserted into one end of a sample and switched on. The thermometers, inserted in holes along the length of the sample, are examined at regular intervals throughout a five-minutes period and their temperatures are recorded. The greater the increase in temperature along the sample, the better its thermal conductivity.

Thermal conductivity test using a thermal circuit

DENSITYA material is dense if it has a high mass to volume ratio. The density of a material is expressed in kg/m³ and can be calculated using the formula:

Density = mass

volume

Dense materials are used where weight is needed such as to prevent items being blown over by the wind or to hold something underwater. Road rollers, hammer heads, diving belts and multi-gyms are some of the products that make use of dense materials. The density of materials can be compared by weighing each sample in turn and dividing by its volume. The higher the figure, the greater the material’s density.

A material being weighed to check its density

ELASTICITY

An elastic material is one that returns to its original shape after being

deformed. Springs, rubber bands and trampolines and car bumpers are

made from elastic materials. A material that does not return to its original

shape after being deformed is said to be plastic.

A test to compare the elasticity of different materials can be conducted

using a set of 100g masses, a retort stand and samples of the materials in

wire form, each 500 mm long with cross-sectional area of approximately 1

mm².

Each sample is tested in turn by securing one end to the top of the stand,

then suspending a mass from the other end. To begin with, a single 100 g

mass is applied. After 30 seconds the mass is removed and the length of the

wire sample is measured and recorded. This process is then repeated with

an additional 100g mass aded each time to a maximum of 1 kg or until the

sample breaks.

If the length of a sample is

unchanged when the mass is

removed, the material has

behaved in an elastic manner

If the length of a sample has

increased when the mass is

removed, the material has

behaved in a plastic manner.

Nearly all materials have elastic

properties below a certain load.

Beyond it, they behave plastically

then break. This load varies from

one material to another. Elasticity test for materials

STRENGTH

A strong material is one that can resist a force without breaking or permanently distorting. A material will have different strengths against different types of force.

A material has tensile strength if it resists stretching forces

A material has compressive strength if it resists squashing forces

A material has bending strength if it resists bending forces

A material has torsional strength if it resists twisting forces

A material has shear strength if it resists shear forces (forces that attempt to cause one part of the material to ‘slide past’ another part)

DIFFERENT TYPES OF FORCE