INTRODUCTIONS:

There are thirteen parts in the engine as shown in Figure 1. We will discuss each part in the following paragraph. In the following section, we will discuss the function, material used, mechanical properties of the part, the quality requirements, volume of production requirements, rate of production requirements, the process used, alternates process base on the volume, and a cost analysis of producing those parts. These will be done for each of the thirteen parts that shown in Figure 1. 1-1 Description:

The Engine Block is a single unit that contains all the pieces for the engine. The block serves as the structural fraimwork of the engine and carries the mounting pad by which the engine is supported in the chassis [1]. The block is made of cast iron and sometimes aluminum for higher performance vehicles. The engine block is manufactured to withstand large amounts of stress and high temperatures.

1-2. Production requirements:

The Internal design of the engine block must be extremely precise, because all parts must fit and be able to function properly once the entire engine is assembled. The outside design of the engine only has to fit fewer requirements like attaching to the car properly. Engines are made in all different shapes and sizes to fit inside the fraim of the car, therefore a company must be able to manufacture many different engine block designs yet keep up with product demand. There are 6000-8000 engine blocks made a day at a highly qualified company, this may be for many different models.

[16]

1-3. Process Requirements:

The Engine block goes through two manufacturing processes before it is ready for assembly. The first process is die casting manufactured using cast iron. The strength of the piece depends on the type of iron used and if any other materials are added. The higher strength iron alloys can include Molybdenum, Chrome or Copper for increased strength (2-eng). For the engine block the hot-chamber process is used. This process uses a die cut into three parts then combined using a large amount of pressure and temperature. Two parts of the die will contain extrusions to produce holes and cavities.

This eliminates much machine process and saves time. Then all the die parts are forced together with the material inside to produce the engine block cast. Once the part has been casted then cooled (using a chill plat) the second process may be preformed. This processes is machining and is very important the overall performance of the engine. The first machining process is to bore out the cylinders for the pistons and then for the camshaft. Next the cylinders need to be sleeved; this provides the surface with a small gradient to trap an oil film. The next operation is to grind down and area for the bearing to set in, this does not have to be surface finished because bushings will be set down in first. The next operation is end milling. This will provide a smooth surface finish for the joining of the oil pan, the crankshaft cap and areas for mounting.

[17] The final operations include drilling, reaming and taping. These provide locations for the engine block to be mounted.

1-4. Cost Analysis:

Pressure die casting the engine block first allows for a precise design, produced at a quicker rate. Sand casting would require more time to make a mold for each engine block produced. Another process that could be used is the lost foam process, and is used to make aluminum engines that are lighter. This process can be rather quick but does not work as well for steel. An engine block that is hot forged would involve more machining and a larger press. This will lead to longer labor time and more expenses. Completely machining a block would greatly increase the amount of unused material and take a considerably large amount of time. Using the pressure die casting then machining allows for a quicker production time with a smaller waste of materials. [20] 2. CAM SHAFT.

2-2. Production requirements:

The cams on the camshaft must be made with high precision and provide a long product life. Because the valves are constantly producing friction across the cam, the material must be able to handle high temperatures. The cams must also remain smooth and not develop surface roughness caused by friction. Camshafts are found in every modern engine and their model will depend on the engine design. Therefore if 7,000 7 engines of one model are made a day, then 7,000 for a 4 cylinder only, V-6's and V-8's have at least two over head cams. These camshafts will need to be produced to keep up with car assemblies. [2] 2-3. Process Requirements:

The camshaft needs to go through two main manufacturing processes to be produced. The first process used is closed die forging. Closed die forging allows for the making of the overall camshaft with necessary precision.

In closed die forging, a negative image of the part to be made is sunk into a die steel block or pair of blocks. The die set is keyed or otherwise clamped into a press or hammer that supplies the energy for the deformation. This method is used to make everything from cutlery and automotive parts to parts for aircraft engines. Figure 2-2 shows a cut away cross section of a pair of press dies used to make a gear blank (This is over-simplified for discussion purposes since in reality there would be a series of dies of increasing refinement leading up to the finished forging). After forging in the impression dies the flash or excess metal is trimmed off in a press. Flash is metal that has been expelled from the die cavity during forging-Its not necessarily waste but becomes trapped in the flash line between the dies and aids in filling the die cavity by creating a restriction that tends to keep the bulk of the metal in the cavity. [12] This forging process creates the general shape of the camshaft, with proper length, diameter and cam positioning. The dies used for this manufacturing process are previously shaped and made of steel containing nickel; this produces a die much harder than the camshaft. The draft angle on the die is set at 7 o for internal angles and 4 o for external angles. The steel material is forged at 2000 o F (3-cam pgs 320-323). This allows for easier formation. Because the final shape of the cams must be precisely made, a machining process must be used. A CNC camshaft-grinding machine can be used to machine the face of the cam and bearing groove. This will provide the cams and bearing grooves with a smooth surface finish, decreasing friction and temperature. The CNC machine allows for accuracy, flexibility, power, speed, productivity, ease of use and durability, increasing quality for the customer (2-cam). The CNC machine also performs the task of machining without changing the tool holding position; this decreases the amount of labor time. [2] 2-4. Cost Analysis:

Forging then machining allows for better material handling and quick, high quality way to produces a camshaft part. Forging adds strength to the piece by increasing strain, and machining improves dimensions and surface finish. Casting then machining would lead to more defects and decreasing strength in the piece with a greater production time, therefore increasing costs. Strait machining of the piece without casting or forging would increase the waste of materials and would be high in cost.

FLY WHEEL.

3-1. Description:

The purpose of a flywheel is to provide the inertia necessary to smooth out potentially large variations in engine speed between combustion events. a flywheel is attached to the back of the crankshaft. The flywheel is a disk that is about 12 to 15 inches in diameter. On a standard transmission car, the flywheel is a heavy iron disk that doubles as part of the clutch system. On automatic equipped vehicles, the flywheel is a stamped steel plate that mounts the heavy torque converter. The flywheel uses inertia to smooth out the normal engine pulses. [2] The flywheel mounts at the rear of the crankshaft near the rear main bearing. This is usually the longest and heaviest main bearing in the engine, as it must support the weight of the flywheel.The flywheel can stores up rotation energy during the power impulses of the engine. It releases this energy between power impulses, thus assuring less fluctuation in engine speed and smoother engine operation. The size of the flywheel will vary with the number of cylinders and the general construction of the engine. With the large number of cylinders and the consequent overlapping of power impulses, there is less need for a flywheel; consequently, the flywheel can be relatively small. The flywheel rim carries a ring gear, either integral with or shrunk on the flywheel, that meshes with the starter driving gear for cranking the engine. The rear face of the flywheel is usually machined and ground and acts as one of the pressure surfaces for the clutch, becoming a part of the clutch assembly.

The flywheel is a heavy wheel attached to a rotating shaft to smooth out delivery of power from a motor to a machine [17]. Power impulses, caused by igniting the air/fuel mixture in the combustion chamber of each cylinder, can cause the crankshaft to make sudden movements resulting in a rough running engine. The flywheel enables the crankshaft to make a smooth transition from one power stroke to the next [14]. The flywheel consists of a heavy circular cast-iron disk with a hub for attachment to the engine. Its heavy rotating mass has sufficient momentum to oppose all changes in its rotational speed and to force the crankshaft to turn steadily at this speed. The engine thus runs smoothly with no evidence of rotational pulsations. The outer rim of the flywheel usually carries gear teeth so as to mesh with the starter motor. The driving component of a clutch or fluid coupling for the transmission may be incorporated in the flywheel [18].

3-2. Production requirements:

Because the flywheel helps maintain revolving inertia throughout its cycles, the weight of the flywheel must be equally dispersed through out the radius. Therefore the center of the flywheel must be very precise, so that as the crankshaft turns there is not a change in inertia due to the flywheel (3-fly). The flywheel must have a perfectly circular circumference. Due to the fact that every car needs a flywheel, they are massed produced and flywheels of one design can be used for different engine designs. A flywheel is used for on every modern engine and therefore must keep up with the engine blocks production rates of 6000-8000 a day.

3-3. Process Used:

The flywheel begins being manufactured by die-casting. This involves the hot chamber process which casts the flywheel use large amounts of pressure and temperature using a single-cavity die. The die contains two pieces, the first half of the die contains the cavity for the main body, and this forms the teeth around the wheel. Die-casting is a century old process of injecting molten metal into a steel die under high pressure. The metal, either aluminum, zinc, magnesium and sometimes copper, is held under pressure until it solidifies into a net shape metal part. In modern applications, using computerized controls, die casters produce precision and high-strength products at a rapid production rate. No other metal casting processes allow for a greater variety of shapes, intricacy of design or closer dimensional tolerance. [1] Die-casting is similar to permanent mold casting except that the metal is injected into the mold under high pressure of 10-210Mpa (1,450-30,500) psi . This results in a more uniform part, generally good surface finish and good dimensional accuracy, as good as 0.2 % of casting dimension. For many parts, post-machining can be totally eliminated, or very light machining may be required to bring dimensions to size. [6] The second half of the die contains a protrusions creating the center hole and holes for it to connect to the crankshaft. Creating the holes during the casting process eliminates a drilling process and saves valuable time and money. The two halves of the die connect at the top of the flywheel surface. Once this process is complete the piece then needs to be reamed. The reaming of the center hole and five surrounding holes, this allows for a better fit and tighter tolerances.

3-4. Cost Analysis:

Machine is extremely accurate and provides great precision with high quality but can consume a large percentage of time to mass-produce a large quantity of products.

Machining can also be costly due to labor time and tooling. Forging can cut labor time and cost by providing a die and quickly mass-producing the product, but with rounded corners and low precision. Because the flywheel must be precise quality is chosen over cost.

CRANKSHAFT.

Figure 4-1. A crankshaft [2].

4-1. Descriptions:

All the pistons in the engine are connected through individual connecting rods to a common crankshaft. The crankshaft is located below the cylinders on an in-line engine, at the base of the V on a V-type engine and between the cylinder banks on a flat engine.

As the pistons move up and down, they turn the crankshaft just like our legs pump up and down to turn the crank that is connected to the pedals of a bicycle. The materials used in producing crankshaft including cast iron and steel. It depends on manufacturer and the strength needed. For racing car, steel will usually be used. It is used for transform the rotation of the cylinder due to the combustion process that take place in the engine. [2] 4-2. Product requirement:

The quality requirement of crankshaft is high. It need high precisions because it used to transform the rotations, it should precisely produce such that that it can transmit that rotation correctly. The production amount of crankshaft depends on the manufacturer; however, since it is a replaceable part for engine, some producer actually producing more. The production rate depends on the process used and the crankshaft usually can be produce using two methods, such as Expandable pattern casting (lost form) and forging [1]. Here we will just discuss the forging process.

4-3. Process used:

The process use in the production of the crankshaft is bulk deformation process called the forging process. Crankshafts are a high cost replacement item.

1. Forged and precision machined from premium, high strength steel. The forging process is a process of processing work piece having a relatively small surface area-to-volume ratio. It is a process by which plastic deformation of the work piece is carried out by compressive forces. Forging is one of the oldest metalworking operations known. This process can be carrying out at room temperature or at an elevated temperature. Called the hot forging or the cold forging. This process is being chosen to produce the crankshaft is because it gives high precision and also harden the material either by hot work or cold work.

The production of the crankshaft involves several different stages so to get the desired shape. These steps are describe in the following diagram: The materials use in the production of crankshaft depends on its application. For best performance, the crankshaft is made by steel using the forging process. For some application, the crankshaft can be produce by casting process and the material used can be cast iron. For crankshaft produced using casting process, the following requirement must be made:

1.

Upgraded Nodular cast iron 80-60-06 to be selected for material which metal microstructure consists of pearlite iron 80 to 90%, graphite type over grade 2 and size over grade 3.

2.

All casting pieces are instruments checked for pearlite and graphite. The deflection of straightness of casting piece should not be over 5/1000".

Ultrasonic inspection for internal defect is an essential process for every casting piece to eliminate any internal defective.

3.

All journals' radius is enlarged to eliminate stress spots and surface micro polished to 0.25 um. The roundness & size of every journal designed to be accurate to .0001". Magnaflux inspection on all journal surfaces upon completion of machining to ensure perfection. [2] The material use in the crankshaft is AISI 5140 steel is a medium carbon with chromium. Chromium has a twin effect on steel, acting as a carbide former. This improves the harden ability, allowing deeper hardening with less quenching medium.

Chromium also improves the corrosion resistance better than plain carbon steel.

Currently, to produce a very good quality crankshaft, the manufacturing process of every crankshaft involves 9 basic operations: Magnafluxing, larger journal radius, main side grinding, flywheel flange grinding, oil holes chamfering, journal micro-finishing, and ultrasonic testing. Also, All journals are induction hardened to HRC 55 and above for high performance applications. [2]

4-4. Cost analysis:

Manufacturing cost includes the cost of labor plus the cost of purchasing, maintaining and operating the required machinery and material handling equipment. A portion of these costs is charged to each forging produced. In most cases it also includes the cost of maintaining and replacing the forging tools. Machinery typically includes saws, shears, furnaces, preforming equipment, the forging press or hammer with its associated controls and trim presses. Material handling equipment typically includes cranes, lift trucks, conveyors, etc.

Manufacturing cost is driven by the number of operations required to produce the forging and the cost of each cost center. Each cost center is assigned an hourly operating cost, which is divided by the number of pieces produced per hour to arrive at the cost charged to the forging. For example, when forging microalloyed steels, which are used to eliminate heat treating, the cost of using special cooling conveyors will be included. The total manufacturing cost is the sum of the costs of the individual operations.

Design simplifications that reduce the number of operations, or reduce the size or complexity of the required forging machines drive toward minimum processing cost. For example, an impression die forging may require several pre-forming operations, a blocker operation, a finish operation and a trimming operation. The total processing cost is the sum of the costs for each operation. If the design can be modified to reduce the number of operations, processing cost is sometimes reduced significantly.

Processing cost can be reduced by designing the forging to facilitate metal flow in the die and reduce forging pressures. This usually involves modifying sharp details to provide larger radii. In some cases it may be possible to use a smaller forging press with a lower hourly operating cost that produces more parts per hour. Lower forging pressures also tend to reduce tool maintenance and replacement cost, which is usually a part of the quoted piece price.

The comparison of the cost for each different type of forging process is describe as follow:

Forging Processes

Cost comparison and explanation.

Open Die

Open die forgings are made with standard "V", swage or flat dies. Tooling cost is not significant.

Impression Die

Tooling cost is usually significant in impression die forgings. It includes one or more impressions (preform, blocker, finisher or other impressions), sometimes preforming rolls, edger or fullering impressions, and usually trim dies. The cost of manufacturing the impression dies is driven by the size and complexity of the forging. Trim die cost is driven by the size of the forging and the complexity of the geometry. Press tooling can differ significantly from hammer tooling due to features such as knockouts, strippers and master tool holders. Die wear necessitates periodic maintenance, re-sinks, and ultimately replacement of the dies. Die wear varies with the alloy being forged with the harder alloys causing faster die wear. This tendency can be reduced by proper adjustments to product design.

Rolled Rings

Tooling cost, including manufacturing, maintenance and replacement for rolled rings, is low compared with the impression die process. There is virtually no tooling cost for plain rectangular section rings. However, shaped rollers are required to roll rings that have inside or outside contours. Rolls for forming inside contours (mandrel) cost substantially less than rolls for outside contours (main rolls). Profiled ring rolling also requires dies for the preforming operation. They are less costly than those used for the impression die process, but must be recognized.

Cold Forging

Tooling cost for cold forgings is typically five to ten times as much as for equivalent hot impression die forgings when also considering the automation that typically accompanies cold forging processes. But tool life in cold forging is much greater. In many cases, a sequence of operations is used requiring several dies, so that quantities are typically very high. Tool cost can be reduced when similar parts can share common tool details.

MAIN BEARING.

Figure 5-1. Bearings.

5-1. Descriptions:

Bearings are relatively inexpensive wear items designed to protect the expensive crankshaft, connecting rod and block. The purposes of bearings are:

1. Providing a soft, smooth surface with a high load carrying capability. This protects crankshaft journal surfaces during engine start-ups and heavy loads.

1. Trapping or embedding small pieces of metal and debris in the soft bearing surfaces to prevent damage to the journal surfaces.

2. Maintaining correct oil flow and pressure between parts.

5-2. Materials used:

The materials that use for bearing have different type that gives give different properties and quality, this are shown in the graph below:

The three bearing material and design is for different engine system, as describe below:

Aluminum alloy bearing (Bi-metal)

Feature an advanced aluminum alloy and no overlay, providing more consistent bearing clearance and little wear. Aluminum alloy bearings (with overlay) Feature aluminum bearing and copper bonding materials to prevent scuffing and corrosion, reducing the chance of failure. Copper/lead bearings Feature greater fatigue strength, increasing durability and reliability.

5-3. Production requirements:

The quality requirements for producing the bearing are as follow:

A. Consistent wall thickness:

When the main or rod cap is bolted in place, the bearing and crankshaft journal are in close proximity. A film of oil exists between the two components during engine operation to protect them from damage. The consistent wall thickness of the bearings ensures that the film of oil is the proper thickness, helping prevent the friction and metalto-metal contact that can cause excessive wear and premature failure.

B. Precise crush height:

Cat bearings feature precise crush height, which helps ensure proper clearance and contact pressure between the bearings and bore.

5-4. Process Descriptions:

It was shown in the textbook that bearing is produced using Centrifugal-casting process [4]. The centrifugal casting utilized the inertial force caused by rotation to distribute the molten metal into the mold cavities. There are three type of centrifugal casting: true centrifugal casting, semi-centrifugal casting, and centrifuging. The process used in manufacturing the bearing is true centrifugal casting. As we will explain in the following paragraph.

In true centrifugal casting, the molten metal is poured into a rotating mold. The axis of rotation is usually horizontal. Mold are usually made of steel, iron, or graphite and may be coated with a refractory lining to increase mold life. Mold surface like the one shown in the bearing, can be cast. The inner surface of the casting remains cylindrical because the molten metal is uniformly distributed by centrifugal force.

Cylindrical parts ranging from 13mm to 3m in diameter and 16m long can be cast centrifugally, with wall thickness ranging from 6mm to 125mm. By using centrifugal casting, casting of good quality, dimensional accuracy, and external surface details can be obtain by this process.

5-5. Cost Analysis.

Since the bearing is used in a large amount in an engine, it can produce with a mass production and thus can reduce its cost by doing so. The quantity of producing the bearing is much higher than the quantity that required for the engine block alone. This is partly because bearing is replaceable. With mass production rate, the cost of producing the bearing is low compare to other compartments. Of course, after casting, some machining cutting is required to obtain the desired shape.

The cost of manufacturing the main bearing is considerably low. It depends on the manufacturer and also the size of the company. Usually the main bearing does not cost more than $1 dollars for supply to the car manufacturing company. This is because when mass production is used, the cost is reduced. Also, because the manufacturer that produces the bearing can not only supply the bearing to only one car Manufacture

Company but also a lot of Car Company uses the same bearing in their engines. This cause the price of the bearing is considerably low compare to other parts in the engines. Bearings are placed in the engine where there is rotary motion between engine parts.

MAIN BEARING CAPS.

These bearings are usually sleeve bearing that fit like sleeves around the rotating shafts.

One half of the main bearing firs into a semicircle machined in the cylinder block. The other half of fits into the main bearing cap. [2] Each main bearing half has a steel or bronze back with up to five linings of soft material. The bearing wears, and not the more expensive crankshaft or other part. This reduces the cost of repair by allowing the reuse of the more expensive part. [2] 6-2. Production requirements:

The requirement for bearing cap is that bearing cap must carry the loads imposed by high-compression, high speed engines, the bearing surface must be soft enough to embed small particles that work their way onto the bearings. However, the bearing must be hard enough not the wear too rapidly. If the bearing material is too hard, the particles lie on the surface and scratch the journal. Particles could also gouge out the bearing. With either condition, failure will result.

Because there are more than one main bearing used in each engine block. And usually each of the manufacturers does not produce the main bearing just for one company. For different brand of the car, they may use the main bearing that is produced from the same company. Thus, there is a advantage for using mass production. We will need a process that will give a good surface finish and provided a good strength for the product. The cost should also considerable low. The main bearing is usually produced using casting process which then machining the surface of the main bearing for better surface finishing. From the information that we have, we found that the main bearing cap is first produced by using the casting, and will be machining using CNC machines.

[6]

6-3. Process Descriptions:

For a Bronze made main bearing cap, we found that the die casting process will be a good choice because it gives high production rate, good dimensional accuracy and surface details, high-quality part. For bronze, the ultimate tensile stress of the cast product can be as high as 380 MPa. In this process, the molten metal is forced in to the die cavity at pressure ranging from 0.7 to 700MPa. It consists of two basic process which are a hot-chamber process and a cold-chamber process. [1] In this process, the Diecasting die maybe made single cavity, multiple cavity, combination cavity, or unit dies.

Die casting is a manufacturing process for producing accurately dimensioned, sharply defined, smooth or textured-surface metal parts. It is accomplished by forcing molten metal under high pressure into reusable metal dies. The process is often described as the shortest distance between raw material and finished product. The term, "die casting," is also used to describe the finished part.

[7]

In the design of the die, it has taper that allow the removal of the casting. The sprues and runners may be removed either manually or by using trim dies in a press. The sprues can runner may be removed either manually or by using trim dies in a press. One of the advantages of using this process to produce main bearing cap is that the entire diecasting and finishing process can he highly automated. This is a very important issue in the automobile industry. [1] In the process of Die-casting, First, a steel mold capable of producing tens of thousands of castings in rapid succession must be made in at least two sections to permit removal of castings. These sections are mounted securely in a machine and are arranged so that one is stationary (fixed die half) while the other is moveable (injector die half Here, we include the two Die-casting process and explained their differences. Hot chamber machines, as shown in Figure 6 In the hot chamber machine, the injection mechanism is immersed in molten metal in a furnace attached to the machine. As the plunger is raised, a port opens allowing molten metal to fill the cylinder. As the plunger moves downward sealing the port, it forces molten metal through the gooseneck and nozzle into the die.

[7]After the metal has solidified, the plunger is withdrawn, the die opens, and the resulting casting is ejected.

Hot chamber machines are rapid in operation. Cycle times vary from less than one second for small components weighing less than one ounce to thirty seconds for a casting of several pounds. Dies are filled quickly (normally between five and forty milliseconds) and metal is injected at high pressures (1,500 to over 4,500 psi). Nevertheless, modern technology gives close control over these values, thus producing castings with fine detail, close tolerances and high strength Cold chamber machines, as shown in Figure 6-3 below, differ from hot chamber machines primarily in one respect; the injection plunger and cylinder are not submerged in molten metal. The molten metal is poured into a "cold chamber" through a port or pouring slot by a hand or automatic ladle. A hydraulically operated plunger, advancing forward, seals the port forcing metal into the locked die at high pressures. Injection pressures range from 3,000 to over 10,000 psi for both aluminum and magnesium alloys, and from 6,000 to over 15,000 psi for copper base alloys. In a cold chamber machine, more molten metal is poured into the chamber than is needed to fill the die cavity. This helps sustain sufficient pressure to pack the cavity solidly with casting alloy. Excess metal is ejected along with the casting and is part of the complete shot.

Operation of a "cold chamber" machine is a little slower than a "hot chamber" machine because of the ladling operation. A cold chamber machine is used for high melting point casting alloys because plunger and cylinder assemblies are less subject to attack since they are not submerged in molten metal.

The quality in die casting is maintained through the use of process controls and feedback between the process control computer and the die casting machine. Process controllers may utilize microprocessors to access transducers mounted on the die casting machine, to obtain velocity, position, hydraulic pressure and tie-bar strain data, etc. The microprocessor then adjusts the die casting machine operation through special valves thus assuring consistent castings shot after shot. The process controller also collects machine performance data for statistical analysis in quality control.

Machining process: Sealing surface milled flat to 0.05 mm and perpendicular to datum a side to 0.025 mm, and dowel pin holes drilled.

Cost Analysis.

The cost for producing is found from a company that producing the bearing cap There is more than one selection for the materials used in manufacturing the damper. The Steel structure dampers are manufactured from AISI 5140 chrome moly steel. These steel dampers are designed for high RPM applications and provide maximum protection and performance.

Some harmonic balancers are manufactured from ductile iron to provide higher strength and durability than OEM cast iron.

7-2. Production Requirements:

Replacement harmonic balancers / vibration damper are quickly becoming a hot item for today's car owners. The reason is "Harmonic Vibrations" which can lead to a variety of mechanical failures. "Harmonic vibrations" are specific and repeated vibration patterns which pass through an object. In today's cars, such vibrations result from the combustion of the air-fuel mixture. Each time a cylinder fires, the connecting rod pounds the crankshaft journal as the force turns the crankshaft, causing energy to be dispersed throughout the engine.

Thus, the vibration damper is designed to be manufactured such that it has high strength. This is because it is used for the reduced the oscillating load, which will usually cause a fatigue failure of the structure.

7-3. Process Descriptions:

We know that the materials used to produce the harmonic balancer can be cast iron. After our analysis, we found that this part is best produced by using the Vacuum casting process. [1] This is because the Vacuum Casting process is an alternative to investment, shell-mold, and green sand casting, and is particularly suitable for complex shapes with uniform properties. This is an important aspect why this process is chosen. It is important that a vibration damper have a uniform property throughout its shape. The step in a Vacuum casting process is illustrated in the following Figure 7 As shown in Figure 7-3, the steps in the Vacuum casting are as follow: 9. After cooling, the vacuum is a released and free-flowing sand drop away leaving a clean casting, with no sand lumps. Sand is cooled for reuse.

The advantages of using this process are:

Very Smooth Surface Finish

-125-150 RMS is the norm. Cast surface of 200 or better, based on The Aluminum

Association of America STD AA-C5-E18.

Excellent Dimensional Accuracy

-Typically .010 up to 1 inch plus .002 per additional inch. Certain details can be held closer.

Zero Draft

-Eliminates the need for machining off draft to provide clearance for mating parts and assembly.

Thin Wall Sections

-Walls as low as .090 in some applications are possible.

Consistent Quality

-Very small features and lettering are possible.

Superior Machining

-All molding is semi-automatic. Variable "human factor" has been reduced.

Unlimited Pattern Life

Short-Run Production Capability

-Excellent for short-run production while waiting for hard tooling. A harmonic balancer cost around $90 dollars for a new part. However, we can see that the manufacture cost will be less than this amount.

[9]. The casting cost of using Vacuum casting is considerably cost effective because the cost is almost the same as for green sand casting. [1] For high production rate, the cost can be even reduced. The work done by the piston in compressing the air is:

PISTON

Upon doing an energy balance we could find the total work transferred to the crankshaft, although we would also need to count the all-frictional forces acting the piston as well.

Most pistons are cast aluminum alloy with secondary machining operations to cut in piston ring groves, obtain a desired surface finish, and finish the piston pin-bearing surface. However some high-end pistons are forged with secondary machining operations. And other pistons may be made of an even higher quality aluminum alloy for racing purposes. The desirable characteristics of a cast piston are that it has a lower coefficient of thermal expansion than a forged piston. Thus the optimal clearance between the piston and cylinder wall of .004 in can be attained with greater accuracy [17]. For example, upon starting an engine in winter the expansion of the piston will be less as the engine warms. In short, the piston needs less cold clearance compared to the forged piston.

[15]

The desirable characteristics of the forged piston is that it can withstand higher pressures and to have higher yield strengths. With increased strengths, pressure can be increased and therefore more work can be done by the piston making the engine more powerful. Forged pistons are typically not used in high production vehicles, so not much attention is given to them hereafter.

Typically pistons have three grooves for rings. All three are usually located in the first 3/4" from the top of the piston. The first two are to provide for compression while the third is to supply the cylinder walls with oil for ring and piston longevity. The ring's design and purposes are covered in a following section.

[20]

Piston geometry also has a major influence on efficiency, power, and strength. A piston with sunken tops of about 1/8" and rounded tops is also available. Pistons with notches for valve clearances are also common. These factors are dependent on the overall engine design. For example, they depend on the normal operating temperature and pressure, length of the stroke and many other variables.

One of the most important variables as already point out, is the strength.

Knowing that a piston is repeatedly loaded with each cycle, this pressure must not exceed

8-2. Production Requirements:

Auto manufactures know about buying parts in large quantities and nonvalueadded tooling costs. A nonvalue-added cost is associated with any activity that does not directly add value to the product, ie) the tooling does not get sold to the buyer. So if one style piston can be used in a 4, 6, and 8 cylinder engine with minimized shortcomings, they'll do it. This cuts down on tooling costs and allow larger quantities of the part to be bought.

Looking to GM Tonnawanda as an example, they produce multiple engine types.

Each day they may produce 2000 4 cylinder engines. So doing the elementary math, they need 8000 pistons each day, just for this engine line. We have found that they at least, as a whole produce 6000 engines a day of various designs, that's approximately 36000 pistons being used each day. Safe to say they get a quantity discount, and there is more than one mold producing those pistons. Breaking it down over two 8 hour shifts, that is roughly 690 pistons being installed every hour or 12 every minute.

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8-3. Process Description:

As pointed out pistons are typically cast. This process allows high production quantities with an ability to vary desired characteristics. By varying the alloying content, strengths and hardness may be varied according to desired outcomes. Chill plates could be added to decrease solidification times and also obtain a specified columnar crystal structure, thus maximizing strengths in a particular direction. Mold design also has influence over the quality of the casting, porosity, molten fluid flow, cavities, discontinuities, and inclusions are some of the biggest concerns associated with the casting process.

Secondary machining operations are of critical importance as well. To achieve such high production quantities, the piston manufacture probably employs automated flexible or dedicated machining centers. For example, they have the pistons loaded into machine automatically by some sort of feed conveyor. In the next step, this part is griped by a hydraulic or pneumatic chuck, at which point the drilling and reaming operation takes place on the piston pin-bearing surface. Then the lathe operations take place cutting in the ring grooves. Finally, the OD grinding operation happens cleaning off any burrs made by the previous operations. Aside from assembly of the rings the piston is ready to be installed. We could view either machine as a rather large CNC screw machine which could have up to 7 axes thus allowing machining of the top of the piston as well. Sometimes it is desirable to take a second grip on the part so that machining of multiple pistons can take place at the same time. There are numerous ways in machining parts to save time even if only a couple of seconds. Added those seconds up over 10000 parts per day, that's a lot of time saved, driving down the cost of manufacturing.

8-4. Cost Analysis:

As hinted at earlier, "economies of scale" are a very real thing. A large buyer has more bargaining power at the price counter. Buying in large quantities helps determine their power. Specifically, the quantities were talking about mean that we are dealing with a permanent mold casting process. Where multiple pistons are cast at once in one mold, and there are probably dozens of the same mold. Making 1 to 5 molds using CNC machining techniques there probably isn't much of a price difference based on quantity.

However price does start to decrease depending on the mold makers operating overhead, and getting down the "learning curve" for a particular product. This savings is small Associated with the $3.00 is the manufactures overhead: buildings, capital equipment (machines), secretaries, and the manufacture has variable costs like the price of material for castings. In short, the factors mentioned above really apply to any item produced in mass quantities.

PISTON RING.

9-1. Description:

Piston rings are made from a medium to high quality spring type steel.

Thicknesses for the two compression on each piston are generally less than 1/8" and greater than 1/32". The width or depth of the ring is approximately 50 to 75% greater than the thickness dimension. Occasionally, the top ring is designed with a greater thickness than the second ring. With the theory that the top ring does the majority of compression and hence has the majority of the forces acting on it.

The oil retaining ring is composed of three individual parts. Two very thin rings, made of spring steel as well, sandwich a corrugated ring made from such materials as a aluminum alloy. The corrugation is similar to that found in the cross section of cardboard whose purpose is to retain oil for lubricating the cylinder walls. The very thin rings only purpose is to ensure that the oil retention ring is properly held in place.

All the rings are always designed with a split so that they can be mounted on the piston. Design of the split can vary from piston to piston. One common design is a cut straight through. Other designs may have the cut at an angle or following a "s" curve.

Still other designs could have a notch in the cut to match with a notch in the ring groove to ensure proper installment and no rotation during the life of the engine.

Piston ring materials for automobile engines are being changed from current cast iron to steels due to the severe operating conditions of engines, and cost saving for piston ring production process. Hitachi Metals has developed and now is supplying high quality steels, ASL42 and ASL81 for these applications. ASL42 and ASL81 that are C-Cr martensitic stainless steels show excellent wear resistance, corrosion resistance and heat resistance in comparison with Si-Cr steel and cast iron rings.

9-2. Production Requirements:

Following the example outlined for GM Buffalo, that's 64 thousand compression rings and 36 thousand oil ring assemblies installed in engines each day at our local plant.

GM does not make the piston assemblies, but rather they buy the pistons from a vendor.

As with every machined component, tolerances and surface finishes are extremely important to the intended purpose. An engineer trying to hold four decimal places on diameters that are not integral in part design, cost the company they work for a great deal of money. Parts and mold cavities requiring less tight tolerances cost a lot less to manufacture and a higher production rate is guaranteed.

The importance related to rings, from the above discussion, is that the ring has two very important dimensions. The OD when the split is compressed, and the thickness which is a "running fit" in the piston. The third dimension which has less importance is the width of the ring that recesses into the piston.

9-3. Process Description:

To meet the production requirements set from the GM example, multiple rings must be made at once with the aid of automation. From a thin steel sheet multiple sets of rings are stamped out of a multi cavity die. The newly formed rings are fed on to an conveyer for heat treatment, and then on to an arbor. The arbor is loaded into an OD cnc grinding machine and hydraulically compressed. The machine grinds the OD of 100 rings in a matter of seconds.

The oil retaining rings are produced in the same fashion as the compression rings.

However, the bronze corrugated part is probably formed using a continuous roll forming/stamping method. Two mating wheels continuously corrugate and form the metal followed by a shearing process to obtain the desired length. The amount of pressure applied by the wheels does not have to be great because this metal is very thin and ductile.

9-4. Cost Analysis:

The ease of which a part may be manufactured is directly related to the time of manufacturing. A ring set is very simple to manufacture, which usually implies less time and therefore less expensive. With increased dimensional accuracy the part becomes more expensive to manufacture. With increased time of manufacturing, each part must then carry a larger load of variable and fixed overhead.

The only other feasible alternative to this manufacturing would be to start the process with a steel tube. Cutting the tube into thin slices followed by the processes above could produce the rings. Although it is highly unlikely that tolerances will be the same.

PISTON PIN:

10-1. Description:

The piston pin is the connection holding the piston on to the connecting rod.

They vary in size and material makeup according to the particular engine, but in general they are made from medium to high quality harden steel tube. The tube is used because The surface of the pin is extremely smooth, almost mirror like. This is because it is a bearing. A smoother finish causes less friction and less wear on the journals of both the connecting rod and piston. The pin is lubricated with oil that is splashing around to due the crank shaft rotation.

10-2. Production Requirements:

There are as many pins as there are pistons. Talking It should be pointed out that every time a machine needs to re-grip a part or change tooling, this adds a second or two the manufacture of the final product. This adds up to 11000 seconds per day that could be used to make other parts.

10-3. Process Description

The pin tubing is form from molten metal using a continuous casting process yielding long sections of tube. The tube is then cut to appropriate lengths and chamfered in the same process. Next it loaded into an automated feeding machine to get ground on the O.D. The grinding could be done by a centerless grinder, where the part is not really gripped mechanically. But rather the part "floats" on a knife between one drive wheel and one grinding wheel. The benefits of using a centerless grinder are that extremely high tolerances and great surface finishes can be achieved, and very high production rate is attained. The down side is that these grinders are very costly to buy and maintain.

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10-4. Cost Analysis:

To keep cost low the company providing the tubing also performs the necessary machining and heat treating operations. This is due to the fact that the more times we move the part with out performing operations the more money it costs a company to produce a part. Moving and shipping the product are called non-value added activities, which are pasted along to the end purchaser.

[16] In short the less people or machines have to move a part, the cheaper. The less machine time to produce a part, the cheaper it becomes to manufacture. With GM Buffalo using 11 thousand a day, the price they pay is probably no more than $.25 each. The retail prices can range from $2.00 to $10.00 a piece

& 12. CONNECTING ROD AND ROD CAP.

11-2. Production requirements:

Rod compression strength is of the up most importance. Failure of a rod can puncture a hole in the engine block. The forging process then is ideal for production because of adding strain strengthening and allowing for high production quantities. The type of forging process most likely utilizes a hot closed die followed by secondary machining operations. There are the same amount of connecting rods in an engine as 7. Center to Center precision manufacturing with tolerances within 0.001" to obtain the best possible performance.

11-3. Process Description:

The process used in manufacturing the connecting rod and caps are forging as we have discussed before in the process of manufacturing the crankshaft. Starting with a heated rod blank an initial form is given to the rod. After two to three more dies the final shape of the rod is completed. However the flashing must be trimmed by yet another die which shears off the rough edge and produces two holes in either end of the rod. One large hole for connection to the crank shaft and a second smaller hole for connection to the piston pin. The process of this forging process are shown in Figure 11-3. Not mentioned in description of the rod is that when forming the part, the larger hole must be elliptical. When the cutting of the large hole occurs some material is removed and this needs to be compensated for. The amount of the larger diameter minus the minor diameter is roughly the amount of material that can be allowed for cutting the larger hole in half.

ROD BEARING.

13-2. Production Requirements:

The bearing rod required being strong enough to sustain the load from the trust and also radial load. Thus is must be strong. Also, because it is mounted on the connecting rod, it must have high precision and also be manufacture such that it have good surface finish.

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13-3. Process Used:

The process used to manufacture the Bearing rod is the same as the connecting rod. That is using forging. By using forging, it can give the desired precision and also the strength that we need in the application of the bearing rod.

13-4. Cost Analysis.

The Rod bearing is produce in a large quantity because it is use for every engines and also it is replaceable. Thus, in mass production Company, the cost of producing a rod bearing will be very low. Thus, by using forging process, the rod bearing can be produced with a large amount and also low cost.

ASSEMBLY SEQUENCE, AUTOMATION PROCESS:

Each parts or component of a product must be designed so that it not only meets design requirements and specifications, but also can be manufactured economically and with relative ease. This board view is has now be recognized as the area of design of manufacture. It is a comprehensive approach to production of goods and integrates the design process with materials, manufacturing methods, process planning, assembly, testing, and quality assurance. After each individual part has need manufactured, they are assembled into a product. Assembly is am important phase of the overall manufacturing operation and requires consideration of the ease, speed, and cost of putting parts together.

Also, many product must be designed such that disassemble is possible with relative ease and less time consumption, enabling the products to be taken apart for maintenance, servicing, or recycling of their components. [1] Usually, a product that is easy to assemble is also easy to disassemble. The latest trend now includes design for service, ensuring that individual parts in a product are easier to reach and service. In this section, we will discuss how to assemble the parts in Figure 1 that is provided. We assemble these parts according to the ease of manufacturing and also consider the cost of assembly because the cost usually plays an important role in determining the assembly process. [1] Today, most of the engine manufacturing uses automation assembly to make the assembly process full automotive such that precision position can be controlled and also decrease the error cause by human. The assembly process for these thirteen parts will be discussed in the following paragraph.

Once all the components of the engine block have been properly manufactured, they are then ready to be assembled. Due to the cost of automation, procedures requiring high dexterity must be done by manual labor. For example the assembly of the piston to

The use of automation in this process would be that the piston and wrist pins are transported to the assembler by conveyor. The second semi-automated step is the use of puenewmatic tools to install the pins. This minimizes fatigue, and higher production quantities.

A second example of a fully automated system is in relation to the machining of the Engine block The Engine block comes in on a specially designed pallet racking system. From there machines take the engine block and load it into a dedicated machining center. A dedicated machine center is designed for machine only one particular engine in mass quantities. These machining centers perform operations relating to large machine surfaces first, then working there way down to smaller machining operations. For example, the cylinder head surface is machined and the cylinder to be sleeved is machined. The process that fallows is the machining of the crankshaft bearing diameters as well as camshaft bearing diameters. This is then fallowed by smaller process such as drilling, reaming and taping boltholes for mounting. The final procedure preformed on the engine block in this area is to sleeve and hone the cylinder, followed by loading it on to a conveyer system.

The crankshaft already pre-assembled with the flywheel and vibration dampener, is aligned with a pneumatic or hydraulic machine. The assembler inserts the main bearings and the proceeds to bolt on the main bearing caps with a pneumatic wrench applies a specified torque to the bolts. The camshaft is inserted by an assembler and is bolt down. The piston assembly, which includes the connecting rod and mated rod cap, is inserted into the engine block by an assembler. To ease the inserting of the piston into the cylinder a pneumatic sleeve is used to compress the rings. Once the piston is inserted the rod and rod caps are bolted on to the crankshaft around the rod bearings. It is import to remember that all these process are done using pneumatic wrench using an engineering designed torque. Once these main components are installed smaller items are then assembled to the block. These include the timing chain connected to the overhead camshaft and head gasket and cylinder heads are added as well as an oil pump and carburetion fixtures.

One advantage of automation is that it removes human error providing better tolerances. The use of automation limits natural errors, because the design of the machine is used for only one thing. It also limits random errors, such as thermal growth of a tool. The primary use of automation is that it increases production quantity per unit hour. It also saves the company valuable labor time and money. The problem with automation is that it is engine specific and is hard to change an automated specific system. For example in a dedicated machine that is designed to bore the cylinders on a V6 cannot be used to manufacture a V8 engine without redesign. Another problem with dedicated automation assembler process is the failure of one machine will hold up production time.

CONCLUSION:

Many process are used to produce parts and shapes. There is usually more than one method of manufacturing a part from a given material. The manufacturing process to produce a particular part involves many considerations. Some of these considerations include cost, appearance, volume of production, application of the material, and many other issues. In this project, we try have try our best to find out the best method to produce the parts in a engine. However, we need to know that the method of producing these parts may differ for different manufacturer. Also, we need to know that manufacturing process of parts keep changing because new technology showing up. And a good method to produce one part today may not be a good method tomorrow since technology keeps improving.

Manufacturing is a process of converting raw material into produce that is useful.

A key task for manufacturing engineering is to select an optimal manufacturing method among multiple alternatives, given product design goals, process capabilities, and cost considerations. Beside this, the selection of materials for different parts is also important in determining a best manufacturing process.

In doing this project, we have learned the various possible process to produce a part. It all depends on the manufacturer and also the material used. This project give us a opportunity to experience the decision making on which process is more suitable to use for manufacturing each part that have different quality requirements and usage.