Aluminium

	Aluminum

13 Al 26.981539	Atomic Number	13
	Atomic Weight	26.981539
	Electron Config.	2-2-6-2-1

Electron configuration order: 1s-2s-2p-3s-3p-3d-4s-4p-4d-4f-5s-5p-5d-5f-6s-6p-6d-7s

Mechanical Properties		Conditions
		Phase	temp. (K)
Density	2700kg/m^3	Solid	298.15
Modulus of Elasticity	62.053 GPa	Solid	0
Poisson Ratio	0.35	Solid
Thermal Expansion Coefficient	2.310x10^-5/K	Solid	298.15

Electrical Properties		Conditions
		Temp. (K)
Electrical Resistivity	2.655x10^-8 W-m	293.15

Thermal Properties		Conditions
		Temp. (K)	Pressure (Pa)
Melting Temperature	933.47 K		101325
Boiling Temperature	2792.15K		101325
Critical Temperature	7850K
Fusion Enthalpy	397J/g		101325
Vaporization Enthalpy	10896.34J/g		101325
Heat Capacity	897J/Kg-K	298.15	100000
Thermal Conductivity	237 W/m-K	300	101325

Forging

A. Definition
Forging is the process by which metal is heated and is shaped by plastic deformation by suitably applying compressive force. Usually the compressive force is in the form of hammer blows using a power hammer or a press.

B. General Forging
Forging refines the grain structure and improves physical properties of the metal. With proper design, the grain flow can be oriented in the direction of principal stresses encountered in actual use. Grain flow is the direction of the pattern that the crystals take during plastic deformation. Physical properties (such as strength, ductility and toughness) are much better in a forging than in the base metal, which has, crystals randomly oriented.

Forgings are consistent from piece to piece, without any of the porosity, voids, inclusions and other defects. Thus, finishing operations such as machining do not expose voids, because there aren't any. Also coating operations such as plating or painting are straightforward due to a good surface, which needs very little preparation.

Forgings yield parts that have high strength to weight ratio-thus are often used in the design of aircraft frame members.

A Forged metal can result in the following

•	Increase length, decrease cross-section, called drawing out the metal.
•	Decrease length, increase cross-section, called upsetting the metal.
•	Change length, change cross-section, by squeezing in closed impression dies. This results in favorable grain flow for strong parts

C. Forging Process

The metal can be forged hot (above recrystallization temperatures) or cold. Open Die Forgings / Hand Forgings: Open die forgings or hand forgings are made with repeated blows in an open die, where the operator manipulates the workpiece in the die. The finished product is a rough approximation of the die. This is what a traditional blacksmith does, and is an old manufacturing process. Impression Die Forgings / Precision Forgings: Impression die forgings and precision forgings are further refinements of the blocker forgings. The finished part more closely resembles the die impression. Design Consideration: • Parting surface should be along a single plane if possible, else follow the contour of the part. The parting surface should be through the center of the part, not near the upper or lower edges. If the parting line cannot be on a single plane, then it is good practice to use symmetry of the design to minimize the side thrust forces. Any point on the parting surface should be less than 75º from the principal parting plane. • As in most forming processes, use of undercuts should be avoided, as these will make the removal of the part difficult, if not impossible. • Recommended draft angles are described in the following table. Material Draft Angle (º) Aluminum 0 - 2 Copper Alloys (Brass) 0 - 3 Steel 5 - 7 Stainless Steel 5 - 8 • Generous fillets and radius should be provided to aid in material flow during the forging process. Sharp corners are stress-risers in the forgings, as well as make the dies weak in service. Recommended minimum radiuses are described in the following table. Height of Protrusion mm (in) Min. Corner Radius mm (in) Min. Fillet Radius mm (in) 12.5 (0.5) 1.5 (0.06) 5 (0.2) 25 (1.0) 3 (0.12) 6.25 (0.25) 50 (2.0) 5 (0.2) 10 (0.4) 100 (4.0) 6.25 (0.25) 10 (0.4) 400 (16) 22 (0.875) 50 (2.0) • Ribs should be not be high or narrow, this makes it difficult for the material to flow.

Tolerances: • Dimension tolerances are usually positive and are approximately 0.3 % of the dimension, rounded off to the next higher 0.5 mm (0.020 in). • Die wear tolerances are lateral tolerances (parallel to the parting plane) and are roughly +0.2 % for Copper alloys to +0.5 % for Aluminum and Steel. • Die closure tolerances are in the direction of opening and closing, and range from 1 mm (0.040 inch) for small forgings, die projection area <>2 (23 in2), to 6.25 mm (0.25 inch) for large forgings, die projection area > 6500 cm2 (100 in2). • Die match tolerances are to allow for shift in the upper die with respect to the lower die. This is weight based and is shown in the the following table. Material Finished Forging Weight Trimmed kg (lb) <> <> > 500 (> 1100) Die Match Tolerance mm (in) Aluminum, Copper Alloys, Steel 0.75 (0.030) 1.75 (0.070) 5 (0.200) Stainless Steel, Titanium 1.25 (0.050) 2.5 (0.100) 6.5 (0.260) • Flash tolerance is the amount of acceptable flash after the trimming operation. This is weight based and is shown in the following table. Material Finished Forging Weight Trimmed kg (lb) <> <> > 500 (> 1100) Flash Tolerance mm (in) Aluminum, Copper Alloys, Steel 0.8 (0.032) 3.25 (0.125) 10 (0.4) Stainless Steel, Titanium 1.6 (0.064) 5 (0.2) 12.5 (0.5) A proper lubricant is necessary for making good forgings. The lubricant is useful in preventing sticking of the workpiece to the die, and also acts as a thermal insulator to help reduce die wear. Press Forgings: Press forging use a slow squeezing action of a press, to transfer a great amount of compressive force to the workpiece. Unlike an open-die forging where multiple blows transfer the compressive energy to the outside of the product, press forging transfers the force uniformly to the bulk of the material. This results in uniform material properties and is necessary for large weight forgings. Parts made with this process can be quite large as much as 125 kg (260 lb) and 3m (10 feet) long. Upset Forgings: Upset forging increases cross-section by compressing the length, this is used in making heads on bolts and fasteners, valves and other similar parts. Roll Forgings: In roll forging, a bar stock, round or flat is placed between die rollers which reduces the cross-section and increases the length to form parts such as axles, leaf springs etc. This is essentially a form of draw forging. Swaging: Swaging - a tube or rod is forced inside a die and the diameter is reduced as the cylindrical object is fed. The die hammers the diameter and causes the metal to flow inward causing the outer diameter of the tube or the rod to take the shape of the die. Net Shape / Near-Net Shape Forging: In net shape or near-net shape forging, forging results in wastage of material in the form of material flash and subsequent machining operations. This wastage can be as high as 70 % for gear blanks, and even 90+ % in the case of aircraft structural parts. Net-shape and near-net-shape processes minimize the waste by making precision dies, producing parts with very little draft angle (less than 1º). These types of processes often eliminate or reduce machining. The processes are quite expensive in terms of tooling and the capital expenditure required. Thus, these processes can be only justified for current processes that are very wasteful where the material savings will pay for the significant increase in tooling costs.

Reaming

A. Definition
Reaming is a process which slightly enlarges a pre-existing hole to
a tightly toleranced diameter.




B. General
Reamer is similar to a mill bit in that it has several cutting edges arranged around a central shaft, as shown below. Because of the delicate nature of the operation and since little material is removed, reaming can be done by hand. Reaming is most accurate for axially symmetric parts produced and reamed on a lathe.

C. Detailed Nomenclature for a Reamer
A more complete listing of reamer nomenclature is provided below.

D. Reamer Part Design

Reamed holes should not intersect with drilled holes, so the configuration below should NOT be implemented:

As with a drilled hole, clearance for chips is needed at the bottom of a reamed hole. This is illustrated below:

Reaming should not be relied upon to correct the location or alignment of a hole. Its primary purpose is to fine-tune the diameter of the hole.

Drilling

A. Definition
The process of using a multi - point tool to penetrate the surface of a workpiece and make a round hole.



B. General
Drilling is easily the most common machining process. One estimate is that 75% of all metal-cutting material removed comes from drilling operations.

Drilling involves the creation of holes that are right circular cylinders. This is accomplished most typically by using a twist drill, something most readers will have seen before. The figure below illustrates a cross section of a hole being cut by a common twist drill:

The chips must exit through the flutes to the outside of the tool. As can be seen in the figure, the cutting front is embedded within the workpiece, making cooling difficult. The cutting area can be flooded, coolant spray mist can be applied, or coolant can be delivered through the drill bit shaft. For an overview of the chip-formation process, see the chip formation section.

C. Characteristics
The characteristics of drilling that set it apart from other powered metal cutting operations are:

• The chips must exit out of the hole created by the cutting.
• Chip exit can cause problems when chips are large and/or continuous.
• The drill can wander upon entrance and for deep holes.
• For deep holes in large workpieces, coolant may need to be delivered through the drill shaft to the cutting front.
• Of the powered metal cutting processes, drilling on a drill press is the most likely to be performed by someone who is not a machinist.

D. Drill Press Work Area
A view of the metal-cutting area of a drill press is shown below. The workpiece is held in place by a C-clamp since cutting forces can be quite large. It is dangerous to hold a workpiece by hand during drilling since cutting forces can unpredictably get quite large and wrench the part away. Wood is often used underneath the part so that the drill bit can overshoot without damaging the table. The table also has holes for drill overshoot as well as weight reduction. A three-jaw chuck is used since three points determine a circle in two dimensions. Four-jaw chucks are rarely seen since offset of the bit is not necessary. The next section contains illustrations of drill bit chuck. To get an idea of the differing configurations of three and four-jaw chucks, please see the equivalent lathe chuck .

Drilling rpm

n = Vc x 1000 / phi x d





Explanation :

• n = rpm
• Vc = Cutting Speed in m/min
• Phi = Constanta 3,14 or 22/7
• d = Drill diameter
  

Milling Rpm

n = Vc x 1000 / phi x d




Explanation :

• n = rpm
• Vc = Cutting Speed in m/min
• Phi = Constanta 3,14 or 22/7
• d = Cutter diameter
  

Material Removal Rate - Machining Power

Chip section

A = a x s (mm^2)

Material removal rate

V = a x s x u (cm^3/min)

Tangential cutting force

F = a x s x Ks ( kgf/mm^2)

Machining power

P = a x s x Ks x V / 60 x 120 x efficiency

Explaination :

• a = depth of cut
• s = feed in mm/rev
• V = cutting speed in m/min
• Ks = spesific cutting force kgf/mm^2

Turning Rpm

n = Vc x 1000 / phi x d




Explanation :

• n = rpm
• Vc = Cutting Speed in m/min
• Phi = Constanta 3,14 or 22/7
• d = Workpiece diameter
  

Bending

A. Definition
Bending is a process by which metal can be deformed by plastically deforming the material and changing its shape.




B. General Bending
The material is stressed beyond the yield strength but below the ultimate tensile strength. The surface area of the material does not change much. Bending usually refers to deformation about one axis.

Bending is a flexible process by which many different shapes can be produced. Standard die sets are used to produce a wide variety of shapes. The material is placed on the die, and positioned in place with stops and/or gages. It is held in place with hold-downs. The upper part of the press, the ram with the appropriately shaped punch descends and forms the v-shaped bend.

Bending is done using Press Brakes. Press Brakes normally have a capacity of 20 to 200 tons to accommodate stock from 1m to 4.5m (3 feet to 15 feet). Larger and smaller presses are used for specialized applications. Programmable back gages, and multiple die sets available currently can make for a very economical process.

Air Bending is done with the punch touching the workpiece and the workpiece, not bottoming in the lower cavity. This is called air bending. As the punch is released, the workpiece ends up with less bend than that on the punch (greater included angle). This is called spring-back. The amount of spring back depends on the material, thickness, grain and temper. The spring back usually ranges from 5 to 10 degrees. Usually the same angle is used in both the punch and the die to minimize setup time. The inner radius of the bend is the same as the radius on the punch.

Bottoming or Coining is the bending process where the punch and the workpiece bottom on the die. This makes for a controlled angle with very little spring back. The tonnage required on this type of press is more than in air bending. The inner radius of the workpiece should be a minimum of 1 material thickness in the case of bottoming; and upto 0.75 material thickness, in the case of coining.

Turning

A. Definition

1. A method for removing the surface from a circular piece by bringing the cutting edge of a tool against it while the piece is rotated.

2. Turning is the machining operation that produces cylindrical parts. In its basic form, it can be defined as the machining of an external surface:

• with the workpiece rotating,
• with a single-point cutting tool, and
• with the cutting tool feeding parallel to the axis of the workpiece and at a distance that will remove the outer surface of the work.

B. Cutting Factors in Turning

1. Speed
Always refers to the spindle and the workpiece. When it is stated in revolutions per minute(rpm) it tells their rotating speed. But the important figure for a particular turning operation is the surface speed, or the speed at which the workpeece material is moving past the cutting tool. It is simply the product of the rotating speed times the circumference (in feet) of the workpiece before the cut is started. It is expressed in surface feet per minute (sfpm), and it refers only to the workpiece. Every different diameter on a workpiece will have a different cutting speed, even though the rotating speed remains the same.

2.Feed
Always refers to the cutting tool, and it is the rate at which the tool advances along its cutting path. On most power-fed lathes, the feed rate is directly related to the spindle speed and is expressed in inches (of tool advance) per revolution ( of the spindle), or ipr. The figure, by the way, is usually much less than an inch and is shown as decimal amount.

3.Depth of Cut
It is practically self explanatory. It is the thickness of the layer being removed from the workpiece or the distance from the uncut surface of the work to the cut surface, expressed in inches. It is important to note, though, that the diameter of the workpiece is reduced by two times the depth of cut because this layer is being removed from both sides of the work.

C. Turning Process

1. Facing Cut

It involves moving the cutting tool across the face (or end) of the workpiece and is performed by the operation of the cross-slide, if one is fitted, as distinct from the longitudinal feed (turning). It is frequently the first operation performed in the production of the workpiece, and often the last- hence the phrase "ending up".

2. Roughing Cut

An initial pass of the cutting tool that emphasizes heavy metal removal rates, high feed rates, and a heavy depth of cut.

3. Finishing Cut

A final pass of the cutting tool that emphasizes dimension accuracy, surface finish, higher speeds and light depth of cut.

D. Turning Machines

1. Turret Lathes

In a turret lathe, a longitudinally feedable, hexagon turret replaces the tailstock. The turret, on which six tools can be mounted, can be rotated about a vertical axis to bring each tool into operating position, and the entire unit can be moved longitudinally, either annually or by power, to provide feed for the tools. When the turret assembly is backed away from the spindle by means of a capstan wheel, the turret indexes automatically at the end of its movement thus bringing each of the six tools into operating position. The square turret on the cross slide can be rotated manually about a vertical axis to bring each of the four tools into operating position. On most machines, the turret can be moved transversely, either manually or by power, by means of the cross slide, and longitudinally through power or manual operation of the carriage. In most cased, a fixed tool holder also is added to the back end of the cross slide; this often carries a parting tool.

2. Single Spindle Automatic Screw Machines

There are two common types of single-spindle screw machines, One, an American development and commonly called the turret type (Brown & Sharp), is shown in the following figure. The other is of Swiss origin and is referred to as the swiss type. The Brown & Sharp screw machine is essentially a small automatic turret lathe, designed for bar stock, with the main turret mounted on the cross slide. All motions of the turret, cross slide, spindle, chuck, and stock-feed mechanism are controlled by cams. The turret cam is essentially a program that defines the movement of the turret during a cycle. These machines usually are equipped with an automatic rod feeding magazine that feeds a new length of bar stock into the collect as soon as one rod is completely used.

3. CNC Machines

Nowadays, more and more Computer Numerical Controlled (CNC) machines are being used in every kinds of manufacturing processes. In a CNC machine, functions like program storage, tool offset and tool compensation, program-editing capability, various degree of computation, and the ability to send and receive data from a variety of sources, including remote locations can be easily realized through on board computer. The computer can store multiple-part programs, recalling them as needed for different parts.

E. Turning Tools

1.

HSS Lathe Turning Tools

2.

Turning Tool Holder

3.

Self Centering Lathe Chucks - 3Jaw

4.

Independent Lathe Chucks - 4 Jaw

5. Lathe Chuck Keys

6. Revolving Center / Live Center

7. Center Drill

8. Lathe Dogs

Iron

A. Definition
The term iron, as used in the chemical or scientific sense of the word, refers to the chemical element iron or pure iron and is the chief constituent of all commercial iron and steel.

B. Occurance
Iron is believed to be the sixth most abundant element in the universe , formed as the final act of nucleosynthesis by carbon burning in massive stars. While it makes up only about 5% of the Earth's crust, the earth's core is believed to consist largely of an iron-nickle alloy constituting 35% of the mass of the Earth as a whole. Iron is consequently the most abundant element on Earth, but only the fourth most abundant element in the Earth's crust. Most of the iron in the crust is found combined with oxygen as iron-oxide minerals such as hematite and magnetite. About 1 in 20 meteorites consist of the unique iron-nickel minerals taenite (35-80% iron) and kamacite (90-95% iron). Although rare, meteorites are the major form of natural metallic iron on the earth's surface.(Wikipedia)

C. Charateristics

Iron is a metal extracted mainly from the iron ore hematite. It oxidises readily in air and water to form Fe₂O₃ and is rarely found as a free element. In order to obtain elemental iron, and other impurities must be removed by chemical oxygen reduction. The properties of iron can be modified by alloying it with various other metals and some non-metals, notably carbon and silicon to form steels.

Nuclei of iron have some of the highest binding energies per nucleon, surpassed only by the nickle isotope ⁶²Ni. The universally most abundant of the highly stable nuclides is, however, ⁵⁶Fe. This is formed by nuclear fusion in stars. Although a further tiny energy gain could be extracted by synthesizing ⁶²Ni, conditions in stars are unsuitable for this process to be favoured, and iron abundance on Earth greatly favors iron over nickel, and also presumably in supernova element production.

Iron (as Fe²⁺, ferrous ion) is a necessary trace element used by almost all living organisms. The only exceptions are several organisms that live in iron-poor environments and have evolved to use different elements in their metabolic processes, such as manganese instead of iron for catalysis, or hemocyanininstead of hemoglobin. Iron-containing enzymes, usually containing heme prosthetic groups, participate in catalysis of oxidation reactions in biology, and in transport of a number of soluble gases. Seehemoghlobin cythocrome, and catalese.

D. Basic Information

Name	Iron
Symbol	Fe
Atomic Number	26
Atomic Weight	55.845
Standard State	Solid at 298 K
CAS Registry ID	7439-89-6
Group in Periodic Table	8
Period in PeriodicTable	4
Block in Periodic Table	d - Block
Colour	Lustrous, metallic, greyish

Resources :
1. http://en.wikipedia.org
2. http://www.webelements.com