THERMODYNAMICS

SPEAKING

A. Discuss the following

Why are radiators important in vehicles?

What’s the function of the ozono layer in the atmosphere?

How does a microwave works?

How is chicken soup made?

What happen if I leave a bowl with water in the open air in a really sunny day?

READING / WRITING

B. Look and study the following notes.

Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation. It interrelates macrosqcopic variables, such as temperature, volume and pressure, which describe physical properties of material bodies and radiation, which in this science are called thermodynamic systems.

Historically, thermodynamics developed out of a desire to increase the efficiency of early steam

engines, particularly through the work of French physicist Nicolas Léonard Sadi Carnot (1824) who believed that the efficiency of heat engines was the key that could help France win the Napoleonic Wars. Scottish physicist Lord Kelvin was the first to formulate a concise definition of thermodynamics in 1854:

“Thermo-dynamics is the subject of the relation of heat to

forces acting between contiguous parts of bodies, and the

relation of heat to electrical agency.”

C. Write one or two paragraphs that summarize the passage and the picture above.

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D. Look and study the following picture.

E. Conduction, Convection, or Radiation?

1. Between a stove and a pot. ____________________________

2. Walking across hot sand burns your feet. ____________________________

3. When nothing is touching the object. ____________________________

4. You accidentally touch a hot stove. ____________________________

5. An iron is used to iron your clothes. ____________________________

6. The doctor takes an X-ray of your body. ____________________________

7. How you get a sunburn. ____________________________

8. The metal part of your seatbelt burns your leg when you sit on it after the car sat in the sun all day. ____________________________

9. You sit near a campfire. ____________________________

10. In a microwave. ____________________________

F. Read the following passage.

LAWS OF THERMODYNAMICS The four laws of thermodynamics

summarize the most important facts of thermodynamics. They define fundamental physical quantities, such as temperature, energy, and entropy, to describe thermodynamic systems and they describe the transfer of energy as heat and work in thermodynamic processes.

Experimentally reproducible distinction between heat and work is at the heart of thermodynamics, and about processes in which this distinction cannot be made, thermodynamics has nothing to say.

ZEROTH LAW

The zeroth law implies that thermal equilibrium, viewed as a binary relation, is a Euclidean relation. If we assume that the binary relationship is also reflexive, then it follows that thermal equilibrium is an equivalence relation. Equivalence relations are also transitive and symmetric. The symmetric relationship allows one to speak of two systems being "in thermal equilibrium with each other", which gives rise to a simpler statement of the zeroth law:

If two systems are in

thermal equilibrium

with a third, they are in

thermal equilibrium

with each other

However, this statement requires the

implicit assumption of symmetry and reflexivity, rather than reflexivity alone.

The law is also a statement about

measurability. To this effect the law allows the establishment of an empirical parameter, the temperature, as a property of a system such that systems in equilibrium with each other have the same temperature. The notion of transitivity permits a system, for example a gas thermometer, to be used as a device to measure the temperature of another system.

Although the concept of thermodynamic

equilibrium is fundamental to thermodynamics,

the need to state it explicitly as a law was not widely perceived until Fowler and Planck stated it in the 1930s, long after the first, second, and third law were already widely understood and recognized. Hence it was numbered the zeroth law. The importance of the law as a foundation to the earlier laws is that it allows the definition of temperature in a non-circular way without reference to entropy, its conjugate variable.

FIRST LAW The first law of thermodynamics may be

expressed by several forms of the fundamental thermodynamic relation:

A change in the internal

energy of a closed

thermodynamic system is

equal to the difference

between the heat supplied

to the system and the

amount of work done by

the system on its

surroundings

For a thermodynamic cycle the net heat

supplied to the system equals the net work done by the system. The net change in internal energy is the energy that flows in as heat minus the energy that flows out as the work that the system performs on its environment. Work and heat are

not defined as separately conserved quantities; they refer only to processes of exchange of energy.

These statements entail that the internal

energy obeys the principle of conservation of energy. The principle of conservation of energy may be stated in several ways:

Energy can be neither

created nor destroyed. It

can only change forms.

In any process in an isolated system, the

total energy remains the same.

SECOND LAW The second law of thermodynamics

asserts the existence of a quantity called the entropy of a system and further states that.

When two isolated systems in separate

but nearby regions of space, each in thermodynamic equilibrium in itself (but not necessarily in equilibrium with each other at first) are at some time allowed to interact, breaking the isolation that separates the two systems, allowing them to exchange matter or energy, they will eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initial, isolated systems is less than or equal to the entropy of the final combination of exchanging systems. In the process of reaching a new

thermodynamic equilibrium, total entropy has increased, or at least has not decreased.

It follows that the entropy of an isolated

macroscopic system never decreases. The second law states that spontaneous natural processes increase entropy overall, or in another formulation that heat can spontaneously be conducted or radiated only from a higher-temperature region to a lower-temperature region, but not the other way around.

The second law refers to a wide variety of

processes, reversible and irreversible. Its main import is to tell about irreversibility.

The prime example of irreversibility is in

the transfer of heat by conduction or radiation. It was known long before the discovery of the notion of entropy that when two bodies of different temperatures are connected with each other by purely thermal connection, conductive or radiative, then heat always flows from the hotter body to the colder one. This fact is part of the basic idea of heat, and is related also to the so-called zeroth law, though the textbooks' statements of the zeroth law are usually reticent about that, because they have been influenced by Carathéodory's basing his axiomatics on the law of conservation of energy and trying to make heat seem a theoretically derivative concept instead of an axiomatically accepted one. Šilahvý (1997) notes that Carathéodory's approach does not work for the description of irreversible processes that involve both heat conduction and conversion of kinetic energy into internal energy by viscosity (which is another prime example of irreversibility), because "the mechanical power and the rate of heating are not expressible as differential forms in the 'external parameters'".

The second law tells also about kinds of

irreversibility other than heat transfer, and the notion of entropy is needed to provide that wider scope of the law.

According to the second law of

thermodynamics, in a reversible heat transfer, an element of heat transferred, δQ, is the product of

the temperature (T), both of the system and of the source or destination of the heat, with the increment (dS) of the system's conjugate variable, its entropy (S)

The second law defines entropy, which

may be viewed not only as a macroscopic variable of classical thermodynamics, but may also be viewed as a measure of deficiency of physical information about the microscopic details of the motion and configuration of the system, given only predictable experimental reproducibility of bulk or macroscopic behavior as specified by macroscopic variables that allow the distinction to be made between heat and work. More exactly, the law asserts that for two given macroscopically specified states of a system, there is a quantity called the difference of entropy between them. The entropy difference tells how much additional microscopic physical information is needed to specify one of the macroscopically specified states, given the macroscopic specification of the other, which is often a conveniently chosen reference state. It is often convenient to presuppose the reference state and not to explicitly state it. A final condition of a natural process always contains microscopically specifiable effects which are not fully and exactly predictable from the macroscopic specification of the initial condition of the process. This is why entropy increases in natural processes. The entropy increase tells how much extra microscopic information is needed to tell the final macroscopically specified state from the initial macroscopically specified state.

Heat cannot

spontaneously flow from

a colder location to a

hotter location.

THIRD LAW The third law of thermodynamics is

usually stated as follows:

The entropy of a perfect

crystal at absolute zero

is exactly equal to zero.

This is explained in statistical mechanics

by the fact that a perfect crystal has only one possible microstate (microscopic state) at extremely low temperatures: The locations and energies of every atom in a crystal are known and fixed. (In quantum mechanics, the location of each atom is not exactly fixed, but the wave function of each atom is fixed in the unique ground state for its position in the crystal.) Entropy is related to the number of possible microstates, and with only one microstate, the entropy is exactly zero.

The third law is also stated in a form that

includes non-crystal systems, such as glasses:

As temperature

approaches absolute

zero, the entropy of a

system approaches a

minimum.

The minimum, not necessarily zero, is

called the residual entropy of the system.

G. Write a well-structure paragraph with title LAWS OF THERMODYNAMICS. (Summarize

the previous reading in two or three paragraphs)

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VOCABULARY

H. Unscramble the words and match them with their definitions.

1. Bsaoluet rzoe The branch of physical science concerned with the interrela- tionship and interconversion of different forms of energy and the behavior of macroscopic systems in terms of certain basic quantities, such as pressure or temperature.

2. Ryefilxevit A quantitative measure of the amount of thermal energy not available to do work.

3. Etnyrpo A state in which all parts of a system are at the same

temperature.

4. Tdherycmiosnaam A collection of ordered pairs of elements.

5. Tyratvnsitii A relationship of characteristic correspondence, equivalence, or identity among constituents of an entity or between different entities.

6. Itseolad symstse The property of a binary relation that expresses the fact that the relation holds between an object and its “mirror image.”

7. Ybnria rtienlao The quality of being measurable

8. Meaytsiulriab A relationship between three elements such that if the relationship holds between the first and second elements and between the second and third elements, it necessarily holds between the first and third elements.

9. Smyrmyet The total heat o system

10. Tamhler Eiqruimliubm A system that cannot exchange matter or energy with its Surroundings.

11. Nte htae The temperature at which molecular activity is at a minimum.

12. Dcseol Semsty Emission and propagation and emission of energy in the form of rays or waves.

13. Cntnioveoc A physical system that does not interact with other systems.

14. Rpssreue Heat transfer in a gas or liquid by the circulation of currents from one region to another.

15. Rdaiatoin Force applied uniformly over a surface, measured as force per unit of area.

GLOSSARY

Absolute Zero

Closed System

Conduction

Conductor

Convection

Efficiency

Entropy

First Law of Thermodynamics

Heat Engines

Insulator

Isolated System

Pressure

Principle of Conservation of

Energy

Radiation

Residual Entropy

Second Law of Thermodynamics

Steam Engines

Thermal Equilibrium

Thermodynamic Equilibrium

Thermodynamic System

Thermodynamics

Third Law of Thermodynamics

Transfer of Heat

Work

Zeroth Law of

Thermodynamics

MANUFACTURING

A. Discuss the following

Where does the sugar come from?

How are chocobananas made?

If you would have money for investing in a home-made product, which product would you

produce?

Which are the materials used for producing wooden tables and chairs?

Which process is described in the picture.

WRITING

B. Look at the picture.

1. What’s the picture about? _______________________________________________________

2. According to the picture, which are the materials needed for manufacturing tires.

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3. Describe the process of tire fabrication.

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READING

C. Read the following passage and make a sketch of self study applying a notetaking

system.

MANUFACTURING Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term

may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale. Such finished goods may be used for manufacturing other, more complex products, such as aircraft, household appliances or automobiles, or sold to wholesalers, who in turn sell them to retailers, who then sell them to end users – the "consumers".

Modern manufacturing includes all intermediate processes required for the production and

integration of a product's components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead.

MANUFACTURING SYSTEMS Craft or Guild System

A guild is an association of craftsmen in a particular trade. The earliest types of guild were formed as confraternities of workers. They were organized in a manner something between a trade union, a cartel, and a secret society. A lasting legacy of traditional guilds is the guildhalls constructed and used as meeting places.

Putting-out system

The putting-out system was a means of subcontracting work. It was also known as the workshop system. In putting-out, work was contracted by a central agent to subcontractors who completed the work in their own facilities, usually their own homes. The domestic system was a popular system of cloth production in Europe.

Mass production

Mass production, flow production, repetitive flow production, series production, or serial production, is the production of large amounts of standardized products, including and especially on assembly lines. The concepts of mass production are applied to various kinds of products, from fluids and particulates handled in bulk (such as food, fuel, chemicals, and mined minerals) to discrete solid parts (such as fasteners) to assemblies of such parts (such as household appliances and automobiles).

Just In Time manufacturing

Just-in-Time (JIT) is a production strategy that strives to improve a business' return on investment by reducing in-process inventory and associated carrying costs. This production method is also called the

Toyota Production System. To meet JIT objectives, the process relies on signals or Kanban (看板,

Kanban) between different points in the process, which tell production when to make the next part. Kanban are usually 'tickets' but can be simple visual signals, such as the presence or absence of a part on a shelf. Implemented correctly, JIT focuses on continuous improvement and can improve a manufacturing organization's return on investment, quality, and efficiency. To achieve continuous improvement key areas of focus could be flow, employee involvement and quality.

Quick notice that stock depletion requires personnel to order new stock is critical to the inventory reduction at the center of JIT. This saves warehouse space and costs. However, the complete mechanism for making this work is often misunderstood.

Lean manufacturing

Lean manufacturing, lean enterprise, or lean production, often simply, "Lean," is a production practice that considers the expenditure of resources for any goal other than the creation of value for the end customer to be wasteful, and thus a target for elimination. Working from the perspective of the customer who consumes a product or service, "value" is defined as any action or process that a customer would be willing to pay for.

Lean manufacturing is a variation on the theme of efficiency based on optimizing flow; it is a

present-day instance of the recurring theme in human history toward increasing efficiency, decreasing waste, and using empirical methods to decide what matters, rather than uncritically accepting pre-existing ideas.

Flexible manufacturing

A flexible manufacturing system (FMS) is a manufacturing system in which there is some amount of flexibility that allows the system to react in the case of changes, whether predicted or unpredicted. This flexibility is generally considered to fall into two categories, which both contain numerous subcategories. The first category, machine flexibility, covers the system's ability to be changed to produce new product types, and ability to change the order of operations executed on a part. The second category is called routing flexibility, which consists of the ability to use multiple qmachines to perform the same operation on a part, as well as the system's ability to absorb large-scale changes, such as in volume, capacity, or capability.

The main advantages of an FMS are its high flexibility in managing manufacturing resources like

time and effort in order to manufacture a new product. The best application of an FMS is found in the production of small sets of products like those from a mass production.

Mass customization

Mass customization, in marketing, manufacturing, call centers and management, is the use of flexible computer-aided manufacturing systems to produce custom output. Those systems combine the low unit costs of mass production processes with the flexibility of individual customization.

Agile manufacturing

Agile manufacturing is a term applied to an organization that has created the processes, tools, and training to enable it to respond quickly to customer needs and market changes while still controlling costs and quality.

Rapid manufacturing

Direct digital manufacturing, sometimes called additive, rapid, direct, instant, or on-demand manufacturing, is a manufacturing process which creates physical parts directly from 3D CAD files or data using computer-controlled additive and subtractive fabrication and machining techniques with minimal human intervention. When a small, low-cost device is used, it is called desktop or personal manufacturing.

Prefabrication Prefabrication is the practice of assembling components of a structure in a factory or other

manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is used to distinguish this process from the more conventional construction practice of transporting the basic materials to the construction site where all assembly is carried out.

Fabrication

This term refers to building metal structures by cutting, bending, and assembling. The cutting part of fabrication is via sawing, shearing, or chiseling, torching with handheld torches (such as oxy-fuel torches or plasma torches); and via CNC cutters (using a laser, torch, or water jet). The bending is via hammering or via press brakes and similar tools. The assembling is via welding, binding with adhesives, riveting, threaded fasteners, or even yet more bending in the form of a crimped seam. Structural steel and sheet metal are the usual starting materials for fabrication, along with the welding wire, flux, and fasteners that will join the cut pieces. As with other manufacturing processes, both human labor and automation are commonly used. The product resulting from fabrication may be called a fabrication. Shops that specialize in this type of metal work are called fab shops. The end products of other common types of metalworking, such as machining, metal stamping, forging, and casting, may be similar in shape and function, but those processes are not classified as fabrication.

D. Read the following passage and write the main idea of each paragraph.

Additionally write next to the picture the number of paragraph that correspond to

the each step of the process.

Par

agra

ph

No

. 1

Portland Cement is a carefully blended combination of lime, silica, alumina and iron oxide. These components are found in materials which fall into two main categories; calcareous (or lime bearing), such as limestone, and argillaceous (or clay-like) such as shale.

Main Idea

Par

agra

ph

No

. 2

The main raw material component of cement is Limestone, which is obtained from our Kleins Point Quarry on the Yorke Peninsula and shipped across St. Vincent Gulf on the Company’s ship M.V. Accolade II, to our Birkenhead plant.

Main Idea

Par

ag

rap

h

No

. 3 Once the Accolade II reaches the Birkenhead plant, the Limestone is transported via conveyor belts to the Limestone Pre-blend

Building, where it is stockpiled into pre-blended heaps of around 25,000 tonnes.

Main Idea

Par

agra

ph

No

. 4

A reclaimer (pictured in the diagram to the right) moves back and forth along the heap scraping a cross section of the limestone. As the newer raw material is stacked on top of older material, the cross-sectioned reclaiming process ensures an even blend of material is reclaimed.

Main Idea

Par

agra

ph

No

. 5

The reclaimed limestone is then transported via belt conveyors to the weigh building where other raw materials, known as ‘fringe’ materials, such as shale, sand and iron oxide are added to the limestone. This blend of materials is fed into a ring roller mill, where it is dried and crushed to a fine state.

Main Idea

Par

agra

ph

No

. 6

This material is now referred to as raw meal and is the feed for the kiln. The drying process in the raw mill uses the hot gases from the kiln, which also transport the raw meal through large electrofilters which separate the solid particles from the gas, allowing the clean gasses to pass into the atmosphere.

Main Idea

Par

agra

ph

No

. 7

The raw meal is then extracted from the electrofilters and conveyed to the 6,000 tonne blending silo. This silo serves, not only as a storage silo, but also thoroughly blends the raw meal into a physically and chemically consistent material, ensuring well controlled, quality product.

Main Idea

Par

ag

rap

h

No

. 8 The raw meal travels through a preheating tower and reaches approximately 900°C before

it enters the kiln. Once the raw meal reaches the rotating kiln, it is heated further which releases carbon dioxide from the limestone. As the heated raw meal proceeds further

down the kiln into the burning zone, temperatures reach in excess of 1400°C causing chemical reactions which convert the raw meal into hard nodules ranging in size from 5-35mm in diameter known as clinker.

Main Idea

Par

agra

ph

No

. 9

The clinker is then cooled, with the heat recovered from this process being re-used in the kiln to increase energy efficiency. After cooling, the clinker is transported from the storage area, via belt conveyers, to the cement mill.

Main Idea

Par

agra

ph

No

. 10

Just before entering the mill, other additives such as gypsum and limestone are added to the clinker in very specific quantities. The mill is a large rotating ball mill which is filled to a certain level with steel balls ranging in size from 17-90mm in diameter. The clinker and additives are crushed and ground between the steel balls until the desired fineness is attained.

Main Idea

Par

agra

ph

No

. 11

The resultant cement powder then exits the mill and passes through a separator, which extracts the coarse cement powder that has not been milled to the required fineness and returns it back into the mill for further milling. The cement meal that passes through the separator is stored in various silos, ranging in size from 500-30,000 tonnes, where it awaits bagging or bulk transportation.

Main Idea

Par

agra

ph

No

. 12

From the bulk silo, the cement is dispatched from our plants in various ways. The majority of our cement is loaded into bulk pneumatic tankers via 24 hour automated weighbridges, where the driver simply drives the vehicle onto the weighbridge, weighs his empty truck, connects the loading chute to the tank and selects the appropriate product. Once loading is finished, the vehicle is then weighed again to determine exactly how much product was loaded, the driver departs and the weighbridge system automatically records the transaction for processing.

Main Idea

Par

ag

rap

h

No

. 13 Some of the cement is transported from the bulk silo to the Despatch Silo where it is packed into 20kg paper bags on the automated Rotopacker and then arranged onto pallets. The cement is also available in 1 tonne bulk bags for manufacturing and construction

purposes and is often loaded into ships where it is transported via sea to various destinations across Australia.

Main Idea

E. Read the following passage.

MANUFACTURING PROCESSES Casting

Casting is a manufacturing process by which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various cold setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods.

Metal casting is one of the most common

casting processes. Metal patterns are more expensive but are more dimensionally stable and durable. Metallic patterns are used where repetitive production of castings is required in large quantities.

Plaster and other chemical setting

materials such as concrete and plastic resin may

be cast using single-use waste molds as noted above, multiple-use 'piece' molds, or molds made of small rigid pieces or of flexible material such as latex rubber (which is in turn supported by an exterior mold). When casting plaster or concrete, the finished product is, unlike marble, unattractive, lacking in transparency, and so it is usually painted, often in ways that give the appearance of metal or stone. Alternatively, the first layers cast may contain colored sand so as to give an appearance of stone. By casting concrete, rather than plaster, it is possible to create sculptures, fountains, or seating for outdoor use. A simulation of high-quality marble may be made using certain chemically-set plastic resins (for example epoxy or polyester) with powdered stone added for coloration, often with multiple colors worked in. The latter is a common means of making attractive washstands, washstand tops and shower stalls, with the skilled working of multiple colors resulting in simulated staining patterns as is often found in natural marble or travertine.

Molding

Molding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern. A mold is a hollowed-out block that is filled with a liquid like plastic, glass, metal, or ceramic raw materials. The liquid hardens or sets inside the mold, adopting its shape. A mold is the counterpart to a cast. The manufacturer who makes the molds is called the moldmaker. A release agent is typically used to make removal of the hardened/set substance from the mold

easier. Typical uses for molded plastics include molded furniture, molded household goods, molded cases, and structural materials.

Forming

Forming, or metal forming, is the metalworking process of fashioning metal parts and objects through mechanical deformation; the workpiece is reshaped without adding or removing material, and its mass remains unchanged. Forming operates on the materials science principle of plastic deformation, where the physical shape of a material is permanently deformed.

Forming processes tend to be typified by differences in effective stresses. These categories and descriptions are highly simplified, since the stresses operating at a local level in any given process are very complex and may involve many varieties of stresses operating simultaneously, or it may involve stresses which change over the course of the operation.

Compressive forming

Compressive forming involves those processes where the primary means of plastic deformation is uni - or multiaxial compressive loading.

Rolling, where the material is passed through a pair of rollers.

Extrusion, where the material is pushed through an orifice.

Die forming, where the material is stamped by a press around or onto a die.

Forging, where the material is shaped by localized compressive forces.

Indenting, where a tool is pressed into the

workpiece.

Tensile forming

Tensile forming involves those processes where the primary means of plastic deformation is uni- or multiaxial tensile stress.

Stretching, where a tensile load is applied along the longitudinal axis of the workpiece

Expanding, where the circumference of a hollow body is increased by tangential loading

Recessing, where depressions and holes are

formed through tensile loading

Combined tensile and compressive forming

This category of forming processes involves those operations where the primary means of plastic deformation involves both tensile stresses and compressive loads.

Bending

This category of forming processes

involves those operations where the primary means of plastic deformation is a bending load.

Bending is a manufacturing process that

produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials, most commonly sheet metal. Commonly used equipment include box and pan brakes, brake presses, and other specialized machine presses. Typical products that are made like this are boxes such as electrical enclosures and rectangular duct work.

In press brake forming, a work piece is

positioned over the die block and the die block presses the sheet to form a shape. Usually bending has to overcome both tensile stresses and compressive stresses. When bending is done, the residual stresses cause the material to spring back towards its original position, so the sheet must be over-bent to achieve the proper bend angle. The amount of spring back is dependent on the material, and the type of forming. When sheet metal is bent, it stretches in length. The bend deduction is the amount the sheet metal will stretch when bent as measured from the outside edges of the bend. The bend radius refers to the inside radius. The formed bend radius is dependent upon the dies used, the material properties, and the material thickness.

There are three basic types of bending on

a press brake; each is defined by the relationship of the end tool position to the thickness of the material. These three are Air Bending, Bottoming and Coining. The configuration of the tools for these three types of bending is nearly identical. A die with a long rail form tool with a radiuses tip

that locates the inside profile of the bend is called a punch. Punches are usually attached to the ram of the machine by clamps and move to produce the bending force. A die with a long rail form tool that has concave or V shaped lengthwise channel that locates the outside profile of the form is called a die. Dies are usually stationary and located under the material on the bed of the machine. Note that some locations do not differentiate between the two different kinds of dies (punches and dies.) The other types of bending listed use specially designed tools or machines to perform the work.

Shearing This category of forming processes

involves those operations where the primary means of plastic deformation is a shearing load.

Shear forming, also referred as shear

spinning, is similar to metal spinning. In shear spinning the area of the final piece is approximately equal to that of the flat sheet metal blank. The wall thickness is maintained by controlling the gap between the roller and the mandrel. In shear forming a reduction of the wall thickness occurs.

Before the 1950s, spinning was

performed on a simple turning lathe. When new technologies were introduced to the field of metal spinning and powered dedicated spinning machines were available, shear forming started its development in Sweden.

In shear forming, the starting workpiece

can have circular or rectangular cross sections. On the other hand, the profile shape of the final component can be concave, convex or a

combination of these two. A shear forming machine will look very much like a conventional spinning machine, except for that it has to be much more robust to withstand the higher forces necessary to perform the shearing operation.

The design of the roller must be

considered carefully, because it affects the shape of the component, the wall thickness, and dimensional accuracy. The smaller the tool nose radius, the higher the stresses and poorest thickness uniformity achieved.

Machining

Machining is any of various processes in which a piece of raw material is cut into a desired final shape and size by a controlled material-removal process. The many processes that have this common theme, controlled material removal, are today collectively known as subtractive manufacturing, in distinction from processes of controlled material addition, which are known as additive manufacturing.

The precise meaning of the term

"machining" has evolved over the past two centuries as technology has advanced. During the Machine Age, it referred to (what we today might call) the "traditional" machining processes, such as turning, boring, drilling, milling, broaching, sawing, shaping, planning, reaming, and tapping. In these "traditional" or "conventional" machining processes, machine tools, such as lathes, milling machines, drill presses, or others, are used with a sharp cutting tool to remove material to achieve a desired geometry. Since the advent of new technologies such as electrical discharge machining, electrochemical machining, electron beam machining, photochemical machining, and ultrasonic machining, the retronym "conventional machining" can be used to differentiate those classic technologies from the newer ones. In current usage, the term "machining" without qualification usually implies the traditional machining processes.

Machining is a part of the manufacture of many metal products, but it can also be used on materials such as wood, plastic, ceramic, and composites. A person who specializes in machining is called a machinist. A room, building, or company where machining is done is called a machine shop. Machining can be a business, a hobby, or both. Much of modern day machining is carried out by computer numerical control (CNC), in which computers are used to control the movement and operation of the mills, lathes, and other cutting machines.

Turning operations are operations that rotate the workpiece as the primary method of moving metal against the cutting tool. Lathes are the principal machine tool used in turning.

Milling operations are operations in which the cutting tool rotates to bring cutting edges to bear against the workpiece. Milling machines are the principal machine tool used in milling.

Drilling operations are operations in which

holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the workpiece. Drilling operations are done primarily in drill presses but sometimes on lathes or mills.

Miscellaneous operations are operations

that strictly speaking may not be machining operations in that they may not be swarf producing operations but these operations are performed at a typical machine tool. Burnishing is an example of a miscellaneous operation. Burnishing produces no swarf but can be performed at a lathe, mill, or drill press.

An unfinished workpiece requiring

machining will need to have some material cut away to create a finished product. A finished product would be a workpiece that meets the specifications set out for that workpiece by engineering drawings or blueprints. For example, a workpiece may be required to have a specific outside diameter. A lathe is a machine tool that can be used to create that diameter by rotating a metal workpiece, so that a cutting tool can cut metal away, creating a smooth, round surface matching the required diameter and surface finish. A drill can be used to remove metal in the shape of a cylindrical hole. Other tools that may be used for various types of metal removal are milling machines, saws, and grinding machines. Many of these same techniques are used in woodworking.

More recent, advanced machining

techniques include electrical discharge machining (EDM), electro-chemical erosion, laser cutting, orwater jet cutting to shape metal workpieces.

As a commercial venture, machining is

generally performed in a machine shop, which consists of one or more workrooms containing major machine tools. Although a machine shop can be a stand-alone operation, many businesses maintain internal machine shops which support specialized needs of the business.

Machining requires attention to many

details for a workpiece to meet the specifications set out in the engineering drawings or blueprints. Beside the obvious problems related to correct dimensions, there is the problem of achieving the correct finish or surface smoothness on the workpiece. The inferior finish found on the machined surface of a workpiece may be caused by incorrect clamping, a dull tool, or inappropriate presentation of a tool. Frequently, this poor surface finish, known as chatter, is evident by an undulating or irregular finish, and the appearance of waves on the machined surfaces of the workpiece.

There are many kinds of machining

operations, each of which is capable of generating a certain part geometry and surface texture.

In turning, a cutting tool with a single cutting edge is used to remove material from a rotating workpiece to generate a cylindrical shape. The speed motion is provided by rotating the workpiece, and the feed motion is achieved by moving the cutting tool slowly in a direction parallel to the axis of rotation of the workpiece.

Drilling is used to create a round hole. It is accomplished by a rotating tool that typically has two or four helical cutting edges. The tool is fed in a direction parallel to its axis of rotation into the workpiece to form the round hole.

In boring, a tool with a single bent pointed tip is advanced into a roughly made hole in a spinning workpiece to slightly enlarge the hole and improve its accuracy. It is a fine finishing operation used in the final stages of product manufacture.

In milling, a rotating tool with multiple cutting edges is moved slowly relative to the material to generate a plane or straight surface. The direction of the feed motion is perpendicular to the tool's axis of rotation. The speed motion is provided by the rotating milling cutter. The two basic forms of milling are:

Joining Welding

Welding is the fabrication or sculptural

process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the workpieces to form a bond between them, without melting the workpieces.

Many different energy sources can be

used for welding, including a gas flame, an electric arc, a laser, an electron beam, friction, and ultrasound. While often an industrial process, welding may be performed in many different environments, including open air, under water and in outer space. Welding is a potentially hazardous undertaking and precautions are required to avoid burns, electric shock, vision

damage, inhalation of poisonous gases and fumes, and exposure to intense ultraviolet radiation.

Until the end of the 19th century, the

only welding process was forge welding, which blacksmiths had used for centuries to join iron and steel by heating and hammering. Arc welding and oxyfuel welding were among the first processes to develop late in the century, and electric resistance welding followed soon after. Welding technology advanced quickly during the early 20th century as World War I and World War II drove the demand for reliable and inexpensive joining methods. Following the wars, several modern welding techniques were developed, including manual methods like shielded metal arc welding, now one of the most popular welding methods, as well as semi-automatic and automatic processes such as gas metal arc welding, submerged arc welding, flux-cored arc welding and electroslag welding. Developments continued with the invention of laser beam welding, electron beam welding, electromagnetic pulse welding and friction stir welding in the latter half of the century. Today, the science continues to advance. Robot welding is commonplace in industrial settings, and researchers continue to develop new welding methods and gain greater understanding of weld quality

Brazing

Brazing is a metal-joining process whereby a filler metal is heated above melting point and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting (liquidus) temperature while protected by a suitable atmosphere, usually a flux. It then flows over the base metal (known as wetting) and is then cooled to join the workpieces together. It is similar to soldering, except the temperatures used to melt the filler metal are higher.

A variety of alloys are used as filler metals

for brazing depending on the intended use or application method. In general, braze alloys are

made up of 3 or more metals to form an alloy with the desired properties. The filler metal for a particular application is chosen based on its ability to: wet the base metals, withstand the service conditions required, and melt at a lower temperature than the base metals or at a very specific temperature. Some of the more common types of filler metals used are

Aluminum-silicon Copper Copper-silver Copper-zinc (brass) Gold-silver Nickel alloy Silver

Cast iron "welding"

The "welding" of cast iron is usually a brazing operation, with a filler rod made chiefly of nickel being used although true welding with cast iron rods is also available. Ductile cast iron pipe may be also "cadwelded," a process which connects joints by means of a small copper wire fused into the iron when previously ground down to the bare metal, parallel to the iron joints being formed as per hub pipe with neoprene gasket seals. The purpose behind this operation is to use electricity along the copper for keeping underground pipes warm in cold climates.

Fastening

A fastener is a hardware device that mechanically joins or affixes two or more objects together. Fasteners can also be used to close a container such as a bag, a box, or an envelope; or they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container, etc. There are also special-purpose closing devices, e.g. a bread clip. Fasteners used in these manners are often temporary, in that they may be fastened and unfastened repeatedly.

Some types of woodworking joints make

use of separate internal reinforcements, such as dowels or biscuits, which in a sense can be considered fasteners within the scope of the joint system, although on their own they are not general purpose fasteners.

Items like a rope, string, wire (e.g. metal

wire, possibly coated with plastic, or multiple parallel wires kept together by a plastic strip coating), cable, chain, or plastic wrap may be used to mechanically join objects; but are not generally categorized as fasteners because they have additional common uses. Likewise, hinges and springs may join objects together, but are ordinarily not considered fasteners because their primary purpose is to allow articulation rather than rigid affixment.

There are three major steel fasteners used

in industries: stainless steel, carbon steel, and alloy steel. The major grade used in stainless steel fasteners: 200 series, 300 series, and 400 series.

VOCABULARY

F. Write the word that correspond to the definition. Use the words in the box.

1. A large edge tool that cuts sheet metal by passing a blade through it.

__________________________

2. A machine or device, such as an airplane, helicopter, glider, or dirigible, that is capable of atmospheric flight. __________________________

3. A person who buys. __________________________

4. A product made by artisans __________________________

5. A sedimentary rock consisting mainly of calcium carbonate, deposited as the calcareous remains of marine animals or chemically precipitated from the sea: used as a building stone and in the manufacture of cement, lime, etc. __________________________

6. A sequence of machines, tools, operations, workers, etc., in a factory, arranged so that at each stage a further process is carried out. __________________________

7. An appliance that does a particular job in the home. __________________________

8. An edge tool with a flat steel blade with a cutting edge

9. An unprocessed natural product used in manufacture. _______________________

10. Association of artisans. __________________________

11. It consist in joining (metals) by applying heat, sometimes with pressure and sometimes with an intermediate or filler metal having a high melting point. __________________________

12. It is the use of machines, tools and labor to produce goods. __________________________

13. One that assumes some of the obligations of the primary contractor. ___________________

14. Process in which power-driven machine tools are used with a sharp cutting tool to mechanically cut the material to achieve the desired geometry. ________________________

15. Processes that use fuel gases and oxygen to weld and cut metals. ______________________

16. The act or process of producing something. __________________________

Aircraft Assembly line Casting Chisel Customer Forging

Guild Guildhall Handicraft Household appliance Manufacturing Kilns

Coarse Production weighbridge Oxy-fuel torches Limestone Raw Material Serial production Shear Standardize

Subcontractor Weld Machining

17. The hall of a guild or corporation. __________________________

18. The manufacture of goods in large quantities, often using standardized designs and assembly-line techniques. __________________________

19. The process of forming (metal, for example) by heating in a forge and beating or hammering into shape. __________________________

20. The process of transferring molten steel to a mould. __________________________

21. To test by or compare with a standard. __________________________

22. Ovens for hardening, burning, or drying substances such as grain, meal, or clay, especially a brick-lined oven used to bake or fire ceramics. __________________________

23. A machine for weighing vehicles by means of a metal plate set into a road.

__________________________

24. Not fine in texture, rough. __________________________

LISTENING

G. Watch the video in this link and describe the process.

www.glasswebsite.com/video/fgmd.asp

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GLOSSARY

Assembling

Brazing

Bulk Product

Casting

Clinker

FMS

Forging

Forming

Guild

JIT

Machining

Manufacturing

Mass Production

Raw Material

Reclaimer

Standardization

Structural Steel

Torching