The Manufacturing Process for Plastic Bags, Pipelines, and the Propeller for an Outboard Maritime Motor - Essay Example

Manufacturing Technology Primary manufacturing is when we make products which can be used as raw material for other products. This is when raw material is changed into semi finished products. Primary manufacturing has three processes: obtaining the material, refining the material, and creating industrial materials. (Teaching with Historic Places Lesson Plan, n.d) The manufacturing process for plastic bags used at supermarkets use he material plastic, sometimes they can use PET / PET / PE and laminated of PA, PET, BOPP, AL, VMPET, VMCPP, PE, CPP. This depends on the type of plastic bag that is being produced. Different bags need different type of material and all these bags can carry different types of products for example: bags made from laminated of PA, PET, BOPP, AL, VMPET, VMCPP, PE, CPP can carry meat and seafood while the bags produced from plastic are normal shopping bags used for promotional items etc. A plastic bag produced with synthetic thermoplastic material has two strips attached to it which are uniformly spaced with relevance to the median longitudinal axis of the sheet of plastic. In the finished bag these extend over the whole height and are arranged in such a way that the width of the space between the lateral folds which are produced after folding the flat band about the median longitudinal axis and then the longitudinally extending weld seam closes the hose thus formed. The sheet is then bent about the longitudinal median axis to form a hose longitudinally open at one side so that the reinforcing strips are opposite one another. Lateral folds are formed in the hose to form two collapsible sidewalls and two reinforced sidewalls, and a longitudinal weld seam is made to longitudinally close the hose. Furthermore, a bottom weld seam transverse to the longitudinal weld seam is made and the so formed bag is separated from the strip and a grip aperture is formed in the upper portion of the bag. The sheet is then bent about the longitudinal median axis to form a hose longitudinally open at one side so that the reinforcing strips are opposite one another. Lateral folds are formed in the hose to form two collapsible sidewalls and two reinforced sidewalls, and a longitudinal weld seam is made to longitudinally close the hose. It is also possible to have the upper portion contoured simultaneously with the forming of the grip aperture. (Method Of Manufacturing Plastic Carrier Bags, n.d) The propeller for an outboard maritime motor is basically the thing that connects the boat with the water. The propeller is the thing that gives you the performance, if the propeller is bad then the boat will perform poorly and if the propeller is in good condition then the boat will perform well. The size of the propeller has two features or dimensions to it: the diameter and the pitch. The diameter of a two-blade propeller is the measurement, in inches, from the outer tip of one blade to the outer tip of the other. The pitch is the measurement in inches of how far forward the prop would "screw" itself if it was rotated in a solid material. (Wawrzyniak, n.d) A boat propeller has some features: a hub which has a front, back and an axis of rotation, this come between the front and the back. A number of blades extend from the hub between the front and the back and each of these blades has a surface adjacent to the hub in a slanted angle to the axis of rotation. The blade tip has an adjacent surface which forms a dihedral angle with the surface that is adjacent to the hub. The surface adjacent to the blade tip is inclined at a greater angle to the hub than the surface adjacent to the hub. Moreover, each and every blade has a trailing edge which extends in a semi circle from the hub and each trailing edge is substantially straight or at a 90 degree angle and an arcuate leading edge extends between a respective blade tip and hub. Each of the leading and trailing edges extend to and abut the hub. On each blade tip there is a flange which is provided and disposed on each blade tip. It extends parallel to the hub axis toward the hub back. The flange can be disposed at more or less a 90 angle with the surface bordering the blade tip and the flange may include an arcuate edge which extends in between the leading and trailing edges. The flange is on the forward camber only. If possible, the blades are given some space in between and around the hub without overlapping. A total of five blades may be provided. Furthermore, the propeller may include a pointed spinner having an aerodynamic connection with the hub front for enabling streamline flow of water there past. There are core holes in the hub which are disposed around the axis; these may provid for preventing shrinkage of the propeller during manufacture, particularly when the material manufacture includes urethane or other chemicals like it. These core holes are only needed when the hub diameter may make the mass off material to be greater which may result in shrinkage during the manufacturing process. In addition, an efficiency of the propeller in accordance with the present invention is enhanced when the leading edge, trailing edge, and the flange arcuate edge comprise featheredges. (Method Of Manufacturing Plastic Carrier Bags, n.d) Sulphuric acid is a clear, colorless, odorless, viscous liquid that is very corrosive. It is often used to monitor a country's degree of industrialization. Sulphuric acid is largely used in agricultural fertilizers. The manufacturing process for a pipeline to carry this corrosive chemical needs to be very precise and accurate. The materials used need to be non-corrosive with sulphuric cid otherwise the pipeline will corrode away very quickly as the main purpose of this pipeline will be to carry this chemical around the chemical plant. We need to make sure that the material for the pipe is acid resistant and to manufacture such material or buy it is very expensive. Thus when we make it we should be very careful and correct. One material is the pipeline pigs which keep the inner wall of the pipe clean. This is possible because the pig body is of elongated cylindrical construction with the outside diameter of the pig body being substantially that of the pipeline in which the pig is to be employed. There are a few methods of making pipes; the manufacturing of pipes had evolved over time. There is the furnace butt-welding process, the wrought iron tubes were formed into 20 foot long pieces of flat stock by drawing the burning hot pieces through a welding bell. This welding bell forced the flat stock into a cylindrical shape. The second type of manufacturing was the furnace lap-welding process. In this the 20 foot long plates were made on pyramid rolls. The long edges of the plates were scarfed from the flame before forming. After this they were shaped by the pyramid rolls. The red hot cans were reheated and the hot air was sent towards the tapered edges, eventually it formed the shape of a circle. The third method of manufacturing pipes was the electric resistance welded pipe. This was made from plates or coils of steel strips. All types of forming for this method were done at room temperature. The edges were sheared; large mills with mechanical rollers shaped the skelp then into a cylinder. The electric current heated the edges, the hot metal bonded as the edges were forced together mechanically. The next type of pipe was the seamless pipe. It was formed from a solid round billet. This billet was made into an oval shape by spiraling it between two rolls. The billet was forced onto and around a stationary piercing mandrel as a tensile-stress-induced separation developed in the center of the oval billet. This was then reheated and pushed over on a solid plug which reduced the thickness. This also helped in making it longer and finally any irregularities were removed making it smooth. The electric flash welded pipe came after this. This was a cold process in which the skelp was formed into 40 foot long cans. The edges were forced together mechanically and an electric current heated it. Any excess material was exuded inside or outside the pipe. Other excess material was trimmed off leaving a flash both inside and outside. The straight seam submerged arc welded pipe is next in line. This was made by cold forming 40 foot long steel plates into cans and then joining the edges with an added filler metal weld. The process is termed submerged-arc because the arc is created between a continuously supplied filler metal and the can and maintained within a bed of powdered flux. The heat melts the flux and the filler weld. Now the double submerged arc process is used. In this both inside and outside weld bead is deposited, super ceded the submerged arc process with its weld bead only on the outside. In this each piece is passed through cold expansion, and internal hydraulic pressure is used to plastically deform the pipe against an external die. (Kiefner and Trench, 2001) Bibliography 1. Boat propeller, Accessed on June 10, 2008 from http://www.freepatentsonline.com/7025642.html 2. John F. Kiefner and Cheryl J. Trench, (2001) Oil Pipeline Characteristics and Risk Factors: Illustrations from the Decade of Construction, Accessed on June 10, 2008 from http://committees.api.org/pipeline/ppts/docs/decadefinal.pdf 3. Max Wawrzyniak, Obsolete Outboards, Accessed on June 10, 2008 from http://www.duckworksmagazine.com/05/columns/max/12/index.htm 4. METHOD OF MANUFACTURING PLASTIC CARRIER BAGS, Accessed on June 10, 2008 from http://www.freepatentsonline.com/3593622.html 5. Teaching with Historic Places Lesson Plan, Accessed on June 10, 2008 from http://www.saugus.mec.edu/District/TAHG/LessonPlans/PrimaryManufacturing.pdf. Read More