Fish Philosophy Essay Example for Free

Fish Philosophy Essay Just finished reading â€Å"FISH Philosophy† the book and so great it was. It’s a tiny book (two hours of focused read would do) that talks about how to transform your work place (or even your life) into a fun place to enjoy and be excited to come to again and again. I don’t want to talk about the great story in the book, and the details of how a fish market ignited the idea – hence the name FISH – for a manager to transform her workplace, as I want to encourage you to get it and read it. The philosophy is simple, and goes by applying four ingredients that will turn the place from stress and dullness into relax and fun. The ingredients of FISH philosophy are as follows: 1. Choose your attitude 2. Play 3. Make their day 4. Be there Ingredient 1 – Choose your attitude: This is the platform to build upon, and the core concept that everything else depends on. You have the freedom of choice of your attitude: an optimistic and happy attitude, or a pessimistic and sad one. Choose to be happy, smiling, easy going, ignorant of mistakes, and you’ll discover how beautiful and shining you and your place would be. On the other hand, choose to be angry, frowning, hard-headed, picky on mistakes, isolated, and you’ll discover how miserable your day would be! â€Å"Choose your attitude† is the hardest ingredients, but sets the stage for all other ingredients to happen. So work on your attitude, and work on it now. Ingredient 2 – Play: Have fun, even if you have lot’s to do with deadlines nearing, and don’t seem to have enough in your schedule. All that stress come from the fact that you prevent yourself from enjoying what you do. Make it a playful project, an enjoyable study, an easy shopping, a fun meeting, etc. If you cannot enjoy what you do, then try to have some pleasant moments between the heavy tasks you work on. Engage with colleagues or family to create a play yard out of your place. Ingredient 3 – Make their day: By having fun yourself, work on extending that to others who surround you. Make their day by expressing how you’re grateful to have them, or by cheering them up. Get them out of their misery by offering advice and help. You cannot imagine how cheerful you would be when giving a hand to someone. Ingredient 4 – Be there: Be present to your family, customers, colleagues, and people by giving full attention to who calls for you to advice or help. Don’t be ignorant to those calls†¦ get to answer them on the spot, or at least dedicate some time to connect with those you care about to listen to. Ignoring a call for help from your wife, your son, a colleague, or a customer could yield to disappointments and sometimes problems that you could’ve avoided earlier. Applying FISH to your life: I actually believe in the importance of these ingredients to have better place whether at home or at work, and below are some ideas I’m thinking of to practice those in my life (both at home and at work): Ideas| At Home| At Work| Choose your attitude| Be happy, smiling, and open-minded, soft, easy going, ignorant to small acts or mistakes. Spell out the good thoughts, and ignore the bad ones. Say hi or salam to everyone you face! | Play| Educate by fun, and stop yelling. Make the shopping a learning experience for your child where he or she looks for the stuff and picks them up. Enjoy home fixes. Watch cartoons with your child while commenting. | Start your meetings with fun or jokesPost some funny pictures or comics to your desk, or common placesHave a board so employees can post some jokesHave a gaming console and work on a gaming competition| Make their day| Compliments, Compliments, Compliments. Bring your wife some flowers. Invite the family to a day out (I really mean the invite here, and not like †¦ we’re bored, let’s go out). Bring your child something he or she likes (candy for instance). | Compliment the work and attitude of your colleagues. Engage with customers and pinpoint their pains and offer solutions with what they already have. Avoid bad news, and be a passenger of the good ones! | Be there| Listen to your wife and don’t offer solutions, just listen (we all can hear, you need to listen! ). Have a conversation with your child on school or how others deal with him. Listen to the unsaid, and express your willingness to offer help if needed. | Listen to pains from colleagues and customers and offer solutionsStop emails and phone calls if someone calls for your adviceGive full attention when talking to your colleagues or customersNot all people are comfortable talking about their problems, so dig deep within the soles and look for faces that need help. | Remember to work hard on setting the stage by choosing the right attitude! Just finished reading â€Å"FISH Philosophy† the book and so great it was. It’s a tiny book (two hours of focused read would do) that talks about how to transform your work place (or even your life) into a fun place to enjoy and be excited to come to again and again. I don’t want to talk about the great story in the book, and the details of how a fish market ignited the idea – hence the name FISH – for a manager to transform her workplace, as I want to encourage you to get it and read it. The philosophy is simple, and goes by applying four ingredients that will turn the place from stress and dullness into relax and fun. The ingredients of FISH philosophy are as follows: 1. Choose your attitude 2. Play 3. Make their day 4. Be there Ingredient 1 – Choose your attitude: This is the platform to build upon, and the core concept that everything else depends on. You have the freedom of choice of your attitude: an optimistic and happy attitude, or a pessimistic and sad one. Choose to be happy, smiling, easy going, ignorant of mistakes, and you’ll discover how beautiful and shining you and your place would be. On the other hand, choose to be angry, frowning, hard-headed, picky on mistakes, isolated, and you’ll discover how miserable your day would be! â€Å"Choose your attitude† is the hardest ingredients, but sets the stage for all other ingredients to happen. So work on your attitude, and work on it now. Ingredient 2 – Play: Have fun, even if you have lot’s to do with deadlines nearing, and don’t seem to have enough in your schedule. All that stress come from the fact that you prevent yourself from enjoying what you do. Make it a playful project, an enjoyable study, an easy shopping, a fun meeting, etc. If you cannot enjoy what you do, then try to have some pleasant moments between the heavy tasks you work on. Engage with colleagues or family to create a play yard out of your place. Ingredient 3 – Make their day: By having fun yourself, work on extending that to others who surround you. Make their day by expressing how you’re grateful to have them, or by cheering them up. Get them out of their misery by offering advice and help. You cannot imagine how cheerful you would be when giving a hand to someone. Ingredient 4 – Be there: Be present to your family, customers, colleagues, and people by giving full attention to who calls for you to advice or help. Don’t be ignorant to those calls†¦ get to answer them on the spot, or at least dedicate some time to connect with those you care about to listen to. Ignoring a call for help from your wife, your son, a colleague, or a customer could yield to disappointments and sometimes problems that you could’ve avoided earlier. Applying FISH to your life: I actually believe in the importance of these ingredients to have better place whether at home or at work, and below are some ideas I’m thinking of to practice those in my life (both at home and at work): Ideas| At Home| At Work| Choose your attitude| Be happy, smiling, and open-minded, soft, easy going, ignorant to small acts or mistakes. Spell out the good thoughts, and ignore the bad ones. Say hi or salam to everyone you face! | Play| Educate by fun, and stop yelling. Make the shopping a learning experience for your child where he or she looks for the stuff and picks them up. Enjoy home fixes. Watch cartoons with your child while commenting. | Start your meetings with fun or jokesPost some funny pictures or comics to your desk, or common placesHave a board so employees can post some jokesHave a gaming console and work on a gaming competition| Make their day| Compliments, Compliments, Compliments. Bring your wife some flowers. Invite the family to a day out (I really mean the invite here, and not like †¦ we’re bored, let’s go out). Bring your child something he or she likes (candy for instance). | Compliment the work and attitude of your colleagues. Engage with customers and pinpoint their pains and offer solutions with what they already have. Avoid bad news, and be a passenger of the good ones! | Be there| Listen to your wife and don’t offer solutions, just listen (we all can hear, you need to listen! ). Have a conversation with your child on school or how others deal with him. Listen to the unsaid, and express your willingness to offer help if needed. | Listen to pains from colleagues and customers and offer solutionsStop emails and phone calls if someone calls for your adviceGive full attention when talking to your colleagues or customersNot all people are comfortable talking about their problems, so dig deep within the soles and look for faces that need help. | Remember to work hard on setting the stage by choosing the right attitude!

Potential for Large Scale Ethanol Production Essay -- Renewable Fuel

Potential for Large Scale Ethanol Production Recent legislation by the Congress of the United States has created a mandate for 5 billion gallons of renewable fuel (notably ethanol) to be consumed annually by 2015. In light of this recent push for alternative fuels, many different biomass solutions have been considered to meet the energy need for the 200 million cars on the road. While the most efficient bio-fuels are derived from palm oil and sugarcane, the Unites States has begun to focus on the more regional corn crops to produce new renewable fuels. This program appears to have great potential towards achieving a sustainable future devoid of foreign oil dependence, until the economic implications of large-scale ethanol production are considered. With that said, it’s important for the United States Government to understand the relative inefficiency, environmental, and social cost of large-scale ethanol production in the US. Ethanol is a fuel grade form of alcohol that is produced from grain fermentation to create a clean, burnable oil alternative (Heinberg, 171). On a small scale, ethanol production appears to be a practical form of energy for farmers, but is limited by its lack of production facilities and unfavorable energy returned on energy invested. Ethanol has an extremely variable EROEI according to several net energy analyses. Cornell professor David Pimentel found a 29% net loss of energy after conducting two independent tests. Both studies found that, â€Å"the fuel cost more energy to produce than it eventually delivered to society.† (Heinberg, 173) While this study painted a negative picture for ethanol production, a USDA researcher recognized as much as a 77% energy profit; although, a ... ... farmers needs. Works Cited Evans, Michael K. The Economic Impact of the Demand for Ethanol. Chicago, IL: Diane Co., 1997. 2 Apr. 2007 . Hebert, Joseph H. "Study: Ethanol Won'T Solve Energy Problems." USA Today. 10 July 2006. 2 Apr. 2007 . Hirsch, Tim. "Brazilian Biofuels' Pulling Power." BBC. 8 Mar. 2007. 2 Apr. 2007 . Pica, Erich. "Power Politics: Linking Congress, Campaign Contributions and Energy Policy." Friends of the Earth 6 (2003): 1-2. 2 Apr. 2007. Segelken, Roger. "Ethanol." Health and Energy. 2 Apr. 2007 . Potential for Large Scale Ethanol Production Essay -- Renewable Fuel Potential for Large Scale Ethanol Production Recent legislation by the Congress of the United States has created a mandate for 5 billion gallons of renewable fuel (notably ethanol) to be consumed annually by 2015. In light of this recent push for alternative fuels, many different biomass solutions have been considered to meet the energy need for the 200 million cars on the road. While the most efficient bio-fuels are derived from palm oil and sugarcane, the Unites States has begun to focus on the more regional corn crops to produce new renewable fuels. This program appears to have great potential towards achieving a sustainable future devoid of foreign oil dependence, until the economic implications of large-scale ethanol production are considered. With that said, it’s important for the United States Government to understand the relative inefficiency, environmental, and social cost of large-scale ethanol production in the US. Ethanol is a fuel grade form of alcohol that is produced from grain fermentation to create a clean, burnable oil alternative (Heinberg, 171). On a small scale, ethanol production appears to be a practical form of energy for farmers, but is limited by its lack of production facilities and unfavorable energy returned on energy invested. Ethanol has an extremely variable EROEI according to several net energy analyses. Cornell professor David Pimentel found a 29% net loss of energy after conducting two independent tests. Both studies found that, â€Å"the fuel cost more energy to produce than it eventually delivered to society.† (Heinberg, 173) While this study painted a negative picture for ethanol production, a USDA researcher recognized as much as a 77% energy profit; although, a ... ... farmers needs. Works Cited Evans, Michael K. The Economic Impact of the Demand for Ethanol. Chicago, IL: Diane Co., 1997. 2 Apr. 2007 . Hebert, Joseph H. "Study: Ethanol Won'T Solve Energy Problems." USA Today. 10 July 2006. 2 Apr. 2007 . Hirsch, Tim. "Brazilian Biofuels' Pulling Power." BBC. 8 Mar. 2007. 2 Apr. 2007 . Pica, Erich. "Power Politics: Linking Congress, Campaign Contributions and Energy Policy." Friends of the Earth 6 (2003): 1-2. 2 Apr. 2007. Segelken, Roger. "Ethanol." Health and Energy. 2 Apr. 2007 . Potential for Large Scale Ethanol Production Essay -- Renewable Fuel Potential for Large Scale Ethanol Production Recent legislation by the Congress of the United States has created a mandate for 5 billion gallons of renewable fuel (notably ethanol) to be consumed annually by 2015. In light of this recent push for alternative fuels, many different biomass solutions have been considered to meet the energy need for the 200 million cars on the road. While the most efficient bio-fuels are derived from palm oil and sugarcane, the Unites States has begun to focus on the more regional corn crops to produce new renewable fuels. This program appears to have great potential towards achieving a sustainable future devoid of foreign oil dependence, until the economic implications of large-scale ethanol production are considered. With that said, it’s important for the United States Government to understand the relative inefficiency, environmental, and social cost of large-scale ethanol production in the US. Ethanol is a fuel grade form of alcohol that is produced from grain fermentation to create a clean, burnable oil alternative (Heinberg, 171). On a small scale, ethanol production appears to be a practical form of energy for farmers, but is limited by its lack of production facilities and unfavorable energy returned on energy invested. Ethanol has an extremely variable EROEI according to several net energy analyses. Cornell professor David Pimentel found a 29% net loss of energy after conducting two independent tests. Both studies found that, â€Å"the fuel cost more energy to produce than it eventually delivered to society.† (Heinberg, 173) While this study painted a negative picture for ethanol production, a USDA researcher recognized as much as a 77% energy profit; although, a ... ... farmers needs. Works Cited Evans, Michael K. The Economic Impact of the Demand for Ethanol. Chicago, IL: Diane Co., 1997. 2 Apr. 2007 . Hebert, Joseph H. "Study: Ethanol Won'T Solve Energy Problems." USA Today. 10 July 2006. 2 Apr. 2007 . Hirsch, Tim. "Brazilian Biofuels' Pulling Power." BBC. 8 Mar. 2007. 2 Apr. 2007 . Pica, Erich. "Power Politics: Linking Congress, Campaign Contributions and Energy Policy." Friends of the Earth 6 (2003): 1-2. 2 Apr. 2007. Segelken, Roger. "Ethanol." Health and Energy. 2 Apr. 2007 .

Discuss Steinbeck’s presentation of The American dream in Of Mice And Men Essay

George and lennie want to recreate happier time â€Å"I could build a smoke house like the one grandpa had† this shows they want to recreate there childhood when they were safe and cosy A kid of paradise with lots of food – a cosy life â€Å"When we kill a pig we can smoke the bacon and the hams and make sausages† So they can eat some rich fresh succulent meat whenever they want it Better working conditions – not getting canned not working if they didn’t want to â€Å"No one could can us an if we don’t Steinbeck’s language shows the dream won’t come true because he uses alliteration to slow down your reading and by the way curley’s wife neck clicks there is no more sound as if the universe came to a massive stand still As soon as he says â€Å"stop† the first time its like running into a brick wall as if its just like boom dead end no way out to late and no more American dreamland then followed by the second as if that was the rest of the wall boxing him in as to seal his fate as lennie says â€Å"i didn’t want to hurt you but george’ll be mad if you go yelling † and then as it dawns on him of what his actions done â€Å"I done a bad thing I done another bad thing † this leaving the reader feeling sorry for lennie as he is a bit simple as if in his head he is still a kid in a full grown mans body . And as Steinbeck writes the end of chapter five his words showing how distressed / depressed and scared for lennie candy is â€Å"poor bastard† and emphasizing how quiet the barn is as if death himself had walked and lingered in the darkened corners of the barn as the darkness appears in as if a symbolic sign of death hovering the ranch with his scythe waiting to collect his crop. Candy cry’s because when he finds curlys wife dead because he knows that it was lennie and that curly is going to kill lennie when he finds out he will chase down lennie like a hound chasing a rabbit homing in waiting for the death blow and after lennies gone so have George and candies dream and as this starts to hit him he starts to worry about his friends and there future . George talks to lennie about the dream before he shoots him so lennies calm and happy not distressed , panicky and depressed so his last moment is one of his favourite memories George decides to go and to shoot lennie so that he can make lennie happy and calm before he is executed rather than lennie upset and crying at the hand of curly just so that lennie can be happy and glad before he is shot which is really good it must take a lot of courage to shoot a friend It’s a shame really been as they nearly had the finance to buy there dream place with all the three of there money put together had enough to place the deal on the house Steinbeck shows that something will go wrong at the end as he got the title for this novel from a poem by the Scottish writer Mr. Robert burns the poem goes like this The best laid schemes o’ mice an men Gang aft agley An’ leare us nought but grief an’ pain For promised joy In other words the plans of mice and men often go ugly and leave nothing but grief and pain when it was promised to give us joy. The story is set back just after the cowboy/bandit era a time were movies were quite and woman were even more so Its set about two friends who travel together and stop off at ranches to do some work before they move on to earn enough money to support there American dream which is that when they have enough money to buy a ranch they saw for 600 American dollars and then they could live of the fat of the land and everything would be perfect â€Å"an if we didn’t like the guy we just say get out and wed have a spare room and if a friend came by we’d say why don’t you stay the night and by god he would† Steinbeck’s idea of the American dream is basically that the dream can only be reached by the wealthy and unavailable to the poor and dreamful

Overview Of Hard Disk Drives - Free Essay Example

Sample details Pages: 14 Words: 4302 Downloads: 10 Date added: 2017/06/26 Category Statistics Essay Did you like this example? LITERATURE REVIEW The suspension manufacturing process is an important research area. So, this chapter presents: An introduction physical components in HDD Don’t waste time! Our writers will create an original "Overview Of Hard Disk Drives" essay for you Create order An introduction component of suspension Finite Element Method Principle types of bending Bending Methods Theoretical Bending Models Design of Experiments Experimental Analysis 2.1 Physical component in HDD The computer hard disk drives (HDD) are used to store a large quantity of information for retrieval as and when required. Figure 2.1 shows the main components of Hard disk drives. A Hard disk drive consists of three important mechanical components such as a fly head mechanism, a head positioning mechanism, and a disk spindle mechanism. However, Read/Write operations on a magnetic disk are performed by the rotational motion of the recording and the radial motion of the recording head using the swing arm actuator. [6]. Figure 2.1: Components of hard disk drive assembly. Table 2.1: Function for component of Hard disk drives Components of hard disk drive Functions HEAD ARM The magnetic element reads/writes magnetic signals SLIDER The strategically shaped block of graphite that carries the head READ/WRITE HEAD It is integrated with slider, which is mounted on the head of suspension. This device used to record information on the disk or read information from it. SUSPENSION The head is attached to this components and it is the carrier for the Slider that allows the head to fly over the disk surface. VCM The VCM or actuator is the device used to position the head arm to different tracks on the surface of the platter. DISK/MEDIA/PLATTERS A thin round aluminum or glass substrate that is coated with a magnetic material. The head writes and reads to/from the disk. SPINDLE/MOTOR Disks are stacked along the length of the spindle and the motor spins the disks at a consistent RPM (Revolutions Per Minute). 2.2 Component of suspension The suspension interconnects carries signals from the write driver to the write head and from the read head to the preamplifier. Therefore, the components of Hard disk drive are composed of Load beam, Mount plate, and Flat flexure circuit as shown in Figure 2.2 [7]. Figure 2.2: The component of the suspension. 2.2.1 Suspension Functions All magnetic Hard disk drive require suspensions to hold/support the Read/Write head and provide precise preload angle (GL) [8]. Figure 2.3: Suspension Functions. A suspension assembly holds recording heads over the spinning disk surface but instead flyà ¢Ã¢â€š ¬? at a precise very small height above the disk surface. It is the suspension that allows the head to fly less than 0.01 micrometer above the disk surface that is rotating continuously at speeds range between 5,400 to 20,000 rpm as shown in Figure 2.4. Human hair~50 mm Dia. Fly height 0.01mm Dust particle ~5 mm Dia. Figure 2.4: The precise very small height above the disk surface. 1. The flying height concern, the ability of the head to read or write data, while insufficient flying height causes the head to scratch the disk surface and destroy the magnetic coating and the data on the disk. The head is able to stay precisely at the correct flying height because of the equilibrium of the upward force of the air driven under the head and the downward force controlled by the suspension assembly as shown in Figure 2.5. Preload angle DGL DGLL Figure 2.5: Force balance on suspension operation. Spring rate is both the output of individual standard Gram load and the displacement, because the individual standard Gram load and displacement are directly affected the spring rate whether low or high Spring rate. The range of changing DGL has low spring rate. On other hand, the range of changing DGL has high spring rate. However, low or high spring rate will be displacement Dz in z direction, if we consider low spring rate better than high spring rate. 2. The suspension must also hold the head at the correct angles in two axes PSA and RSA simultaneously. 3. The suspension must also optimize resonance for provide less off-track movement during seek. 4. Others critical parameters as customer requirement. 2.3 Finite Element Method 2.3.1 Introduction Considered to the direct methods, the finite element technique further offers the idea of discretization, this time of the very structure or solid under investigation. This allows broadening the class of problems amenable to solution so as to include those dealing directly with modern technology. On the other hand, a sufficiently fine mesh and/or high order of approximation within elements ensure that the error is kept reasonably small. This technique requires the processing of extensive data and may efficiently be implemented with the help of computers only. 2.3.2 Fundamental Concepts FEM cuts a structure into several elements (pieces of the structure). Then it reconnects elements at à ¢Ã¢â€š ¬Ã…“nodesà ¢Ã¢â€š ¬? as if nodes were pins or drops of glue that hold elements together. This process results in a set of simultaneous algebraic equations. Figure 2.6: Many engineering phenomena can be expressed by à ¢Ã¢â€š ¬Ã…“governing equationsà ¢Ã¢â€š ¬? and à ¢Ã¢â€š ¬Ã…“boundary conditionsà ¢Ã¢â€š ¬?. Figure 2.7: FEM Resolution way; FEM approximates problem equations to a set of algebraic equations. K = Property U = Behavior F = Action Figure 2.8: Behavior is the unknown parameter of the problem. 2.3.4 Basic steps in the Finite Element Method The basic steps involved in and finite element analysis consist as shown in Figure 2.9 [9]. Post-processing Phases Solution Phase Preprocessing Phase Figure 2.9: Basic steps in the Finite element method. 2.3.4-1 Preprocessing phase 1. Create and discretize the solution domain into finite element; that is, subdivide the problem into nodes and elements. 2. Assume a shape function to represent the physical behavior of an element; that is an approximate continuous function is assumed to represent the solution of an element. 3. Develop equation for an element. 4. Assemble the element to present the entire problem. Construct the global stiffness matrix. 5. Apply boundary conditions, initial conditions, and loading. 2.3.4-2 Solution phase Solve a set of linear or nonlinear algebraic equations simultaneously to obtain nodal results, such as displacement values at different nodes or temperature values at different nodes in a heat transfer problem. 2.3.4-3 Post-processing phase Obtain other important information. At this point, we may interest in values of principal stresses. 2.4 Principle types of Bending 2.4.1 Introduction Sheet-metal parts are typically produced by a sequence of bending operations. The bending process starts with a flat part and ends up with a three-dimensional object of interconnected planes. Sheet metal bending and metal forming is performed with the use of a metal bending machine called press brake, using various tool and holding resources. Tools consist of dies and punches of different shape and length. There is also a need of grippers that hold the part during operations. The workpiece to be metal formed is placed in the machine and the shoes are raised with elevation levers. The work is then slid into place, and the shoes lowered back down onto the piece to be formed. Metal bending occurs by applying force to the bending lever on the bending brake as shown in Figure 2.10. Adjustment bolts determine the radius of the metal bend. Minimum bend radius is a function of the ductility and thickness of the material being worked. It is needful to bend the work slightly beyond the desired angle because the sheet metals will springback. Sheet metal bending is carried out in metal fabrication shops [10]. (a) (b) (c) (d) Figure 2.10: Sheet metal bending process. (a): position part on the die; (b): position punch on the part; (c): perform bending; (d): take out the part. 2.4.2 Design parameters The problems associated with forming high strength steel often are created during the design stage, when products are designed in such a way that they cannot be manufactured using conventional stamping methods. Or the product requires numerous or special offline operations, such as annealing or normalizing. Further, few of the most important part characteristics that need to be addressed during the design stage [10]. 2.4.3 Bending Radius and Bending Angle Bending dies should be designed so as to avoid sharp bent edges. The inside bending radius ri1,mm depends on the sheet metal thickness s [mm] and should be selected to be as large as possible, because sharp bent edges may lead to material failure. On principle, the bending radius should assume the values recommended by DIN6953. When bending sheet metal, particular attention should also be paid to the rolling direction for bending is transverse to the direction of the sheet metal, r1, min [10]. Figure 2.11: Elastic recovery after Bending. Remember that a small profile radius not only may cause an embrittlement fracture, but also can reduce the metal flow inward. Metal that is not in radial compression has very little resistance to flow. For example, the side walls of a deep-draw box have very little resistance to flow and are not as sensitive to the limiting draw ratio; however, the corners of the box are in radial compression. This radial compression causes a resistance to flow. Increasing the radius size reduces the amount of compression, resulting in increased metal flow inward [10]. 2.4.4 Springback When designing a bending die, it is necessary to consider springback that occurs after unloading. The material has a tendency to partially return to its original shape because of the elastic recovery of the material as shown in Figure 2.11. This is influenced not only by the tensile and yield strengths, but also by thickness, bend radius and bend angle. Springback occurs with all types of forming by bending, when bending in presses, folding, roll forming and roll bending. As a result of springback, the bending die angle a does not correspond precisely to the angle desired at the workpiece a2. The angle ratio is the so-called springback factor kR, which depends on the material characteristics and the ratio between the bending radiuses and sheet metal thickness (r/s) [10]. 2.5 Bending Methods There are so many types of bending operation. Most common methods for bending metal sheet are: Wiping Die Bending, Double Die Bending, and Roll Bending [11]. 2.5.1 Wiping Die Bending Wiping die bending is also known as flanging. One edge of the sheet is bent to 90 while the other end is restrained by the material itself and by the force of blank-holder and pad. The flange length can be easily changed and the bend angle can be controlled by the stroke position of the punch. Figure 2.12: Wiping Die Bending. 2.5.2 Double Die Bending Double die bending can be seen as two wiping operations acting on the work piece one after another. Double bending can enhance strain hardening to reduce springback. Figure 2.13: Double Die Bending. 2.5.3 Roll Bending The operations described in this section use rolls to form sheet metal. Roll bending is an operation in which large sheet-metal parts are formed into curved sections by means of rolls. As the sheet passes between the rolls, the rolls are brought toward each other to a configuration that achieves the desired radius of curvature on the work. A related operation is roll straightening in which nonflat sheets are straightened by passing them between a series of rolls. The rolls subject the work to a sequence of decreasing small bends in opposite directions, thus causing it to be straight at the exit [12]. Figure 2.14: Roll Bending. 2.6 Theoretical Bending Models Bending along a straight line is the most common of all sheet forming processes; it can be done in various ways such as forming along the complete bend in a die, or by wiping, folding or flanging in special machines, or sliding the sheet over a radius in a die. A very large amount of sheet is roll formed where it is bent progressively under shaped rolls. Failure by splitting during a bending process is usually limited to high-strength, less ductile sheet and a more common cause of unsatisfactory bending is lack of dimensional control in terms of springback [15]. 2.6.1 Variables in bending a continuous sheet To consider a unit width of a continuous sheet in which a cylindrical bent region of radius of curvature à ? is flanked by flat sheet as shown in Figure 2.15. The bend angle is ÃŽÂ ¸, and a moment per unit width M, and a tension (force per unit width) T are applied. We note that the tension T is applied at the middle surface of the sheet. The units of M are [force] [length]/ [length] and of T [force]/ [length]. Figure 2.15: A unit length of a continuous strip bent along a line. 2.6.2 Geometry and strain in bending In bending a thin sheet to a bend radius more than three or four times the sheet thickness, it may be assumed that a plane normal section in the sheet will remain plane and normal and converge on the centre of curvature as shown in Figure 2.16. Figure 2.16: Deformation of longitudinal fibers in bending and tension. In general, a line CDO at the middle surface may change its length to CD if, for example, the sheet is stretched during bending; i.e. the original length lO becomes. A line AB0 at a distance y from the middle surface will deform to a length. The axial strain of AB is where ÃŽÂ µa is the strain at the middle surface or the membrane strain and ÃŽÂ µb is the bending strain. Where the radius of curvature is large compared with the thickness, the bending strain can be approximated as, The strain distribution is approximately linear as shown in Figure 2.17. Figure 2.17: Assumed strain distribution in bending. 2.6.3 The pure bending calculation of beam The pure bending operation mention as below section, which is calculated for the theoretical bending moment [13].The simple case of pure bending is examined that the possessing a vertical axis of symmetry, subjected to equal and opposite and couples as shown in Figure 2.18. Figure 2.18: Pure bending. The stress is needed to assured that is consistent with the boundary conditions at ends. These condition are required the results of the internal forces be zero. Therefore, the bending moments about the neutral axis equal the applied moment, : , An expression for normal stress can be written as follows. This is familiarly elastic flexure formula applicable to straight beams applicable. Since, given section, I and M are constant; the maximum stress is obtained by taking: Where S is the elastic section modulus, these formula is widely employed in practice because if its simplicity and facilitate its use also. This,, is regularly used as a measure of the bending strength of materials. 2.6.4 Plastic deformation Unlike elastic deformation, during which, for example, a rod under a tensile load returns to its initial length as long as a defined value (elastic limit of the material) is not exceeded, a workpiece which is plastically deformed retains its shape permanently [14]. Figure 2.19: Tension test bar change in length under stress. 2.6.5 Deformation resistance The resistance to be overcome during a deformation is composed of the flow stress and the friction resistances in the tool, which are brought together under the term à ¢Ã¢â€š ¬Ã…“resistance to flowà ¢Ã¢â€š ¬? [14]. Kf=Flow stress which is direct variation as follows material, type of force, true strain, strain rate, and Temperature. Kr=Friction between tools with material which is direct variation as follows lubricate, surface by surface between tools and material, Temperature, Specify compression stress between tools work piece. Ki= the geometric of forming area, from stress of forming area and relations between Kf and Kr. 2.6.6 Choice of material model for forming In the experiment, the material model for the bending have as actual stress-stain curve. In general material will have an elastic, plastic strain-hardening behavior [15]. Figure 2.20 shows that several example of material behavior are given in many cases. The magnitude of the strain is depending on the bend ratio, this is defined as the ratio of the radius of curvature to sheet thickness,. Figure 2.20: Material models for bending. (a) An actual stressà ¢Ã¢â€š ¬Ã¢â‚¬Å"strain curve. (b) An elastic, perfectly plastic model. (c) A rigid, perfectly plastic model. (d) A strain-hardening plastic model. 2.6.6-1 Strain-hardening model The preload forming process deforms the stainless steel material into some angles, which use a strain-hardening plastic model [15]. Other material of preload forming is not formed by forming tools, which is only assembled with the stainless steel. So, we will describe its behavior as shown in Figure 2.20(d), the strain-hardening model is large the strain. The elastic strains can be neglected, and the low strain hardening model is used, the model expresses as following. Where is strength coefficient Table 2.2 Typical values of strength coefficient K and strain hardening exponent n for selected metals. Material Strength Coefficient, K Strain Hardening Exponent, n MPa lb/in2 Aluminum, pure, appealed 175 25,000 0.20 Aluminum, alloy, appealeda 240 35,000 0.15 Aluminum, alloy, heat treated 400 60,000 0.10 Copper, pure, annealed 300 45,000 0.50 Copper alloy,brassa 700 100,000 0.35 Steel, low C, appealeda 500 75,000 0.25 Steel, high C, appealeda 850 125,000 0.15 Steel, alloy, appealeda 700 100,000 0.15 Steel, stainless, austenitic, appealeda 1200 175,000 0.40 2.6.6-2 Bending without tension The workpiece is bent by a pure moment without any tension or compression being applied, the neutral axis will be at the mid-surface [15]. The pure bending process is examined here for elastic bending and strain-hardening as the following. 2.6.6-3 Elastic bending The linear elastic is bent of sheet shows the material models in the Figure 2.21. The material model [15] of elastic bending as shown in Figure 2.21(a) where the yield stresses- is S. The relationship of stressà ¢Ã¢â€š ¬Ã¢â‚¬Å"strain relation is given as . The distribution shown in Figure 2.21(b), the distribution of stress in Figure 2.21(c). Figure 2.21: Linear elastic bending of sheet showing the material model (a), the strain distribution (b), and the stress distribution (c). The stress at a distance y from the neutral axis, is The moment at the section for elastic spring back, is Figure 2.22: Moment curvature diagram for elastic bending. Where is the second moment of area for a unit width of sheet, and is the curvature. The limit of elastic bending is when the outer fibre at reaches the plane strain yield stress S. The limiting elastic moment is given by The curvature at this moment is; From Figures 2.22 shown that the moment, curvature diagram are within this elastic range, which is a linear. 2.6.7 Elastic unloading and spring back If a sheet is bent by a moment to a particular curvature, as shown in Figure 2.23, and the moment then released [15]. There will be a change in curvature and bend angle. The length of the mid-surface is This will remain unchanged during unloading as the stress and strain at the middle surface are zero. From this, we obtain in which = constant, we obtain Figure 2.23: Unloading a sheet that has been bent by a moment without tension. 2.7 Design of Experiments In engineering, experimentation shows an important role in new product design, manufacturing process development, and process improvement. The object in many cases may be to develop a robust design. In this study, design of experiments (DOE) will be used to optimize composite design tools to minimize variation in forming process. Usually, experiments are performed to gain insight about a process so that conclusions and decisions can be made to develop design tools, and mathematics model. Statistically designed experiments make it possible to test several process key parameter input variables (KPIV) simultaneously in order to assess the effect of each on the process key parameter output variables (KPOV). At composite manufacturing, processes are geared towards factors significant and as-significant production runs. This approach is known as à ¢Ã¢â€š ¬Ã…“sequential experimentation. In general, experiments are used to study the performance of design. The design can be represented by the model as shown in Figure 2.24. We can usually visualize the process as a combination of machines, methods, people, and other resources that transforms some input into an output that has one or more observable responses. Some of the process variables x1, x2 and so on are controllable, whereas other variables z1, z2 and so on are uncontrollable. Inputs (KPIV) X1, X2, X3, X4à ¢Ã¢â€š ¬Ã‚ ¦Xn Outputs (KPIV) Y Design forming Process Figure 2.24: General mathematical model of process and design. The process variation or error, e, will be some function of many component errors. e = e1 + e2 + e3 + à ¢Ã¢â€š ¬Ã‚ ¦ en The central limit theorem states that the distribution of the linear function of errors will tend to normality almost irrespective of the individual distributions. The error in an experiment or process can arise in an additive manner from several independent sources; consequently, the normal distribution becomes a plausible model for the combined experimental for process error. 2.8 Experimental Analysis In this section, we will focus on the HDD suspension and the researches that relate for background of this thesis, these topics are discussed follows. Esat et al. (2002) Finite element analysis of spring in bending of aluminum sheets [2]. In manufacturing industry, the bending operation involves with springback. Therefore, it is a practical problem to predict the final geometry of the workpiece after elastic springback recovery and also the design a appropriate tools in tools for compensate for springback , So, this research uses the commercial software for finite for finite element method (FEM) to analyze plastic strains and the equivalent von misses stresses are presented. The results of FEA are comparing with the empirical data, which is a good agreement of its result. The numerical method analyze and design bending dies, punch, and others parameter. Because of it uses very short period of time, the FEA is possible to obtain suitable dies that compensate for springback. On the other hand, the manufacturing process are trial and error procedures that a long time and the result wastage of material and effort. Chou,I.N Hung, C. (1997). Finte element analysis and optimization on springback reduction [3].Several springback reduction techniques used in the U-channel bending processes were analyzed with the finite element method, which included are bottoming, pinching die and spanking and movement techniques. The relationship between the amount of springback and the forming parameters in each technique was first established through finite element simulations, and then the optimization analysis was coupled with the finite element analysis to find the optimum forming parameters for each springback reduction technique. Siwakorn Srisawat (2008). He study simulation model for reducing residual stress in HDD suspension during forming process [16]. One component of the HDD suspension is the flat TG, which is formed into a curved TG during the TG forming process. This process leaves residual stress in the TG walls. This residual stress could affect the head gimbal assembly at factories and also the response of the HDD operation. A simulation model in finite element analysis is proposed in this paper to address two aims. The first is improved prediction of elastic springback as forming TG is an elastic-plastic recovery phenomenon during unloading that leads to springback. The second aim is to reduce the residual stress that occurs in TG during its forming process. Kazan Recep al. (2002) Prediction of springback in wipe-bending process of sheet metal using neural network [17]. The wipe-bending is one of processes the most frequently used in the sheet metal product industry. Furthermore, the springback of sheet metal, which is defined as elastic recovery of the part during unloading, should be taken into consideration so as to produce bent sheet metal parts within acceptable tolerance limits. Springback is affected by factors such as sheet thickness, tooling geometry, lubrication conditions, and material properties and processing parameters. In this paper, the prediction model of springback in wipe-bending process was developed using artificial neural network (ANN) approach. Here, several numerical simulations using finite element method (FEM) were performed to teaching data of network. The learned network is numerically tested and can be easily implemented springback prediction for new cases. Tekiner Zafer. (2004) the examination of springback of sheet metal with several thicknesses and properties in bending dies [18]. The bending die has an importance in the sheet metals product industry. However, the springback of the sheet metal may be taken into consideration in the bending die design for an experimental study. There are two types of the bending die have been conducted to study that is V-bending die and this is a subdivided into corner bending in the air. The springback must be known in order to produce bent sheet metal part within the acceptable tolerance limits. In this research carried out on the determination of amount springback of bent products. The modular V-bend die many induces the several sheet metal with the bending angles for the amount of springback. The amount of springback results are in line with the result of pervious researches. Ekaratch et al.(2008) Vibration analysis of suspension in HDD with FEM [19] the vibration of slider or Read/Write head is one of the major concerns for hard disk drive manufacture. R/W head is an important part that performs read/write data on the media. The air pressure, caused by air flow through the gap between R/W head and media, sustain the flight height of slider above the media, called air bearing. In general, the gap between the head and the media is very small. Thus, if the vibration level of the Head-Suspension is too high, the head and the media could come into contact and damage both components. The main objective of is work is to study the mechanical vibration of suspension that holds R/W head. The Finite Element model of suspension is conducted having air bearing stiffness between the Head and the media as a combination of linear springs. The natural frequencies and the corresponding mode shapes of the combined system are employed to use in conjunction with mechanical t roubles and cost occurred for testing physical models. Kajonsak et al. (2009) He had studied of HGA behaviors after mounted with Shipping Comb [20]. In Head Stack Assembly process, a shipping comb is mounted to HAS adjacent the HGA area. This is to prevent the vibration of the sliders, attached at the end of suspension, when joining HAS to the other parts or conduct the measurements, storage and transportation. This work is aimed to study the behaviors of HGA when shipping comb. Having various dimensions and shapes, is mounted on using Finite Element analysis for analysis and comparison Gram load value. The components of Shipping Comb are 5 parts Swage shuttle fixture, fixture, Spreader pins, Load cell and Gripper.