Tolerable Tracing Techniques for the 3 30 MKIII - Term Paper Example

THE ANALYSIS AND SPECIFICATION OF MANUFACTURING PROCESSES: DESIGN OF A 3” 30° MKIII HIGH LIFT FOOT VALVE Client Insert Name Client Insert Institution Client Insert Due Date The Analysis and Specification of Manufacturing Processes: Design of a 3” 30° MKIII High Lift Foot Valve Introduction Any design process requires astute understanding of the required functions intended for the product under consideration for design. With a good understanding of the functions intended for the product, this enables the designer to have an idea of the manufacturing process as well as the materials and methods that are relevantly fit for use in the process of designing and manufacturing the product (Bosserman 2010). According to Bosserman (2010), it is important to ensure that these two fundamental attributes of any design process are well understood and appreciated before commencement of any design work can be considered. When there is insufficient information about these attributes of the manufacturing process, there is a great likelihood that the process may not go on well and in return may not help accomplish the objective of having a creative and sufficiently done design. Possible Design Methods for the 3” 30° MKIII High Lift Foot Valve There are two ways through which the 3” 30° MKIII High Lift Foot Valve can be designed and manufactured. The first method is Investment Casting. According to Degarmo, Black & Kohser (2003), investment casting is also called lost-wax casting is a metal forming industrial process that has been in use for over 5000 years from the concept of bees forming wax moulds to form specific patterns within their hives. The method in modern times has been improved with high-technology waxes, specialized alloys and refractory materials which help produce components with high accuracy, versatility, integrity, and repeatability in different metals and alloys (Bosserman 2010). The second method of manufacturing that can be used for this 3” 30° MKIII High Lift Foot Valve is the Computer Numerical Controlled (CNC) Milling. This process involves drilling and cutting using computer guided machines where it uses a rotating cylindrical cutting tool. The way the system is set, its cutter is able to rotate on multiple axes to create different shapes, holes, and slots (Degarmo, Black & Kohser 2003). In addition to this, the system allows the work-piece to be moved across the milling tool in different directions to enable greater maneuverability and hence greater capacity to be made into different shapes (Degarmo, Black & Kohser 2003). CNC Milling devices are of different types and shapes based on the number of axes that they operate around and these are usually labeled with different letters such as X, Y, and Z. The x-y plane refers to the machine’s movement horizontally, forward and back as well as sideways whereas the z plane refers to the machine’s movement vertical movement, up and down (Sias 2006). There is also the w-plane which refers to the machine’s movement diagonally moving across a plane that is vertical (Degarmo, Black & Kohser 2003). Investment Casting Manufacturing Process for the 3” 30° MKIII High Lift Foot Valve As has been described above, investment casting is a manufacturing process that uses coated wax patterns on refractory ceramic material to create the desired shapes of the design. The ceramic is allowed to cool and harden which allows its internal geometry to take the shape of the casting used. A machining tool is then made by pouring molten metal wax into the cavity that had the wax pattern allowing the metal to solidify inside the ceramic mould and the finished product is obtained by breaking the metal casting (Sias 2006). This method is chosen over the CNC Milling method because the former is cheaper and less complicated to use when manufacturing highlift footvalve. This method does not require the use of complex computer aided equipment but instead only requires a well designed wax pattern and casting metal to manufacture the desired product. Therefore, the selection was based on cost and complexity which make it easier and more affordable for production. The Investment Casting Manufacturing Process Plan for the 3” 30° MKIII High Lift Foot Valve with figures This process involves different dependent processes that start with the manufacturing of the wax pattern to be used for the making of the 3” 30° MKIII High Lift Foot Valve and for this design, it is made of wax rather than plastic since the former melts out easily afterwards and can easily be reused (Sias 2006). For the 3” 30° MKIII High Lift Foot Valve design, it mould will be cast after careful calculations of the required shape keeping into consideration the shrinkage of wax and the ceramic material as well as the metal casting itself. Figure 1 below shows the end product that is desired to be achieved by this process. Fig. 1: The Finished Product of the 3” 30° MKIII High Lift Foot Valve In order to achieve this high-end product, the first step is to draw the design of the 3” 30° MKIII High Lift Foot Valve with the design specifications that are required. The Fort Vale Engineering design has an inlet flange drilled 8 by 14mm holes equidistant on a 178mm PCD and the outlet flange are drilled 4 by 17mm holes that are also equidistant on a 160mm PCD. The main contact parts of the valve are manufactured in a 316 stainless steel with Fortyt O ring to main poppet used as the standard (Kalpakjian & Schmid 2006). The following are the specifications of the valve (see figures 2 to 4): Its weight is 8.7 kg Its design pressure (MAWP) is 58 PSI Its hydraulic test pressure is 87 PSI Its design temperature range is -200C to 2000C Fig. 2: The Fitting Details of the 3” 30° MKIII High Lift Foot Valve – top view Fig. 3: The Fitting Details of the 3” 30° MKIII High Lift Foot Valve – side view Fig. 4: The Fitting Details of the 3” 30° MKIII High Lift Foot Valve – Sectional view The mold that is made for this design combines different wax patterns to form a single casting and a ceramic pouring cup is attached at the end of the bar. In some other cases, this can be achieved by attaching the wax patterns on a wax bar with ceramic pouring cup at the top of it making a system that is referred to as Wax pattern tree as seen in figure 7 below. Figure 5 shows the wax pattern that is designed for this process which is then dipped in a refractory slurry that is composed of very fine grained silica, binders and water to obtain a ceramic layer on top of the surface of the pattern (Kalpakjian & Schmid 2006). In order to increase the thickness of the ceramic coat, this pattern is constantly and repeatedly dipped into the slurry and after attaining the required thickness of about 10mm, the coated pattern is then allowed to cool down (see figure 6). Fig. 5: The Wax pattern for the 3” 30° MKIII High Lift Foot Valve – Wax Pattern Fig. 6: Refractory slurry invested over wax pattern of the 3” 30° MKIII High Lift Foot Valve Fig. 7: Investment Casting Wax Pattern Tree for the 3” 30° MKIII High Lift Foot Valve Fig. 8: Wax melted out of the mold of the investment casting The next step of the investment casting process is important in helping establish a strong product for effective use. The ceramic mold that is already hardened to the required hardness is heated to a temperature of 1750C while turned upside down and this process helps the wax to flow out of the mold to leave the metal casting empty (see figure 8). After this process, the ceramic mold is further heated to about 10000C to strengthen it and remove any leftover wax and contaminants and this is followed by pouring metal casting while the mold is still hot. This helps the liquid metal to flow easily through the cavity created to give best dimensional accuracy for the valve being manufactured (Kalpakjian & Schmid 2006). Costing and Pricing The manufacture of the 3” 30° MKIII High Lift Foot Valve has many vote heads that have to be well understood in order to be able to provide the appropriate quotation. There are four criteria that guide the pricing and costing of the designed footvalve and they are as follows: Raw materials – this refers to the direct materials that are required for the manufacture of the foot valve. It includes the cast iron/stainless steel materials that form the most part of the valve and the slurry and molten cast iron that is also used in the process of manufacture (Kalpakjian & Schmid 2006). Direct labor costs – this refers to the costs that are associated with the employees that work towards the manufacture of the valve throughout the whole production process. Variable overhead costs – this refers to the costs that are not constant or directly involved in the manufacturing process. This costs vary because they increase and decrease in quantity from time to time as the production process increases or decreases depending on the attributes involved (Kalpakjian & Schmid 2006). These costs include electricity bills, rental payments and communication costs all of which affect the production costs in one way or another. Fixed overhead costs – this refers to the indirect costs of production that do not fluctuate from time to time based on the production quantities manufactured. Some of the most important fixed costs include salaries given to specific production personnel that do not work directly towards the manufacture of the valve such as administrative personnel, security guards, and executive/management leadership of the company. Another fixed overhead cost is the depreciation of production buildings and equipment as well as other manufacturing assets that would eventually require renovation and replacement after a certain length of time. Lastly, occupancy costs such as insurance for the building and some machinery as well as property taxes also form part of the fixed overhead costs that eventually affect the pricing of the manufactured products in the end (Kalpakjian & Schmid 2006). Usually, Kalpakjian & Schmid (2006) indicate manufacturing processes do not usually produce single products for economic prudency’s sake and so usually manufacture hundreds or thousands of units and from these units, the cost for a single unit is estimated. For the design manufacture of the 3” 30° MKIII High Lift Foot Valves at Forte Valve Engineering, the following is the summary of the costing and pricing schedule used: Production Capacity – 150000 Units Actual Capacity – 120,000 units Production Cost Components Unit Price ($) Annual Total ($) Raw Materials 215 25,800,000 Direct Labor 125 15,000,000 Variable Manufacturing overhead costs 70 8,400,000 Total variable manufacturing costs 410 49,200,000 Fixed manufacturing overhead costs 350 42,000,000 Total manufacturing costs 760 91,200,000 Bibliography Bosserman, B. 2010. "Control of Hydraulic Transients". Pumping Station Design, vol. 3, no. 5, pp. 153 - 171 Degarmo, E., Black, J. & Kohser, R. 2003. Materials and Processes in Manufacturing (9th edn.). New York: Wiley Press. Sias, F. 2006. Lost-wax Casting: Old, New, and Inexpensive Methods (illustrated ed.), New York: Woodsmere Press. Kalpakjian, S. & Schmid, S. 2006. Manufacturing Engineering and Technology (5th ed.). 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