Engineering

Two of Two TITLE OF ASSESSMENT: Manufacturing Systems  and Quality MODERATED: KR PLEASE READ ALL INSTRUCTIONS AND INFORMATION CAREFULLY. This assignment contributes 5 0% to your final module mark. Please ensure that you retain a duplicate of your assignment. We are required to send samples of student work t o the external exa miners for moderation purposes. It will also safeguard in the unlikely event of your work going astray. THE FOLLOWING LEARNING OUTCOMES WILL BE ASSESSED: Knowledge an understanding of: Modern manufacturing economics, systems and organisation Skills and the ability to: Undertake a costing analysis for a range of product types. Apply the basic principles of quality control IMPORTANT INFORMATION You are required to submit your work within the bounds of the University In fringement of Assessment Regulations (see your Programme Guide). Plagiarism, paraphrasing and downloading large amounts of information from external sources, will not be tolerated an d will be dealt with severely. Although you should make full use of any s ource material, which would normally be an occasional sentence and/or paragraph (referenced) followed by your own critical analysis/evaluation. You will receive no marks for work that is not your own. Your work may be subject to checks for originality whic h can include use of an electronic plagiarism detection service. Where you are asked to submit an individual piece of work, the w ork must be entirely your own. The safety of your assessments is your responsibility. You must not permit another student acces s to your work. Where referencing is required, unless otherwise stated, the Harvard referencing system must be used (see your Programme Guide). Submission Date and Time 4 th May 201 7 Submission Location Online EAT104: Coursework 2: 20 1 6 /20 1 7 Session M anufacturing: Economics, Quality and Organisation This work contributes 50% of the marks allocated to the module. This work covers Learning Outcomes 3, 5 and 6. Learning Outcomes 1, 2 and 4 were covered by the elements within “Coursework 1”. The task s comprising this assessment are given below. Part A comprises a series of quantitative questions relating to manufacturing economics and quality control. Part B comprises CES exercises which relate to manufacturing economics and some environmental impacts associated with manufacturing. PART A : Quantitative Analysis A 1. A company wishes to introduce a new product. In order to do this, it must invest in some new manufacturing equipment. The choice is between Machine A and Machine B. Costs and income a ssociated with each machine are as follows. Costs / Income Machine A Machine B Fixed Costs £75,000 £87,000 Variable Cost per Product Produced £13 £10.50 Selling Price for each Product £25 £25 Plot separate break - even graph s (Costs/Income - v - No of Pr oducts) for Machine A and Machine B . Which machine would you recommend for purchase? Why? (1 5 marks) A 2. A batch of 2500 components is manufactured by an operator. Each of these components takes 4 minutes to make. The direct materials costs are £2 per component. The operator is paid £15 per hour (direct labour costs) . If the total overheads in this company are calculated at 350% of direct labour costs, what is the true cost of manufacturing each component? ( 10 marks) A 3. (a) A potential 6 - year manufa cturing project requires the purchase of a new piece of machinery. You are the project manager and you must choose between two potential machines (Machine A and Machine B), either of which would be suitable. The cost of each machine is identical at £80,0 00. However, they differ in performance such that the projected future cash flows are different for each machine. Projected cash flows over the 6 years of the project are as follows in Table Q A 3: Table Q A 3: Six year cash flow figures for Machine A and Machine B. Year Cash Flow: Machine A Cash Flow: Machine B 0 - £80,000 - £80,000 1 £5,000 £35,000 2 £8,000 £25,000 3 £12,000 £18,000 4 £20,000 £10,000 5 £25,000 £7,000 6 £30,000 £5,000 (i) By simple inspection of the cash flow figures, estimate the payback period for each machine and thereby state which machine you would choose and justify your choice. (ii) Your colleague disagrees with your choice. Sugg est one valid reason why your colleague’s choice may be justified? ( 10 marks) ( b ) Calculate the total NPV for each machine after 6 years assuming a discount (inflation) rate of 7% for each year of the project. Table B3b provides a list of discount factors for a range of discount/inflation rates. (10 marks) (c) Calculate the total NPV for Machine A only assuming a discount (inflation) rate of 4% for each year of the project. Hence calculate the Internal Rate of Return (IRR) for Machine A over the 6 year p eriod by a graphical method. ( 10 marks) Table B 3 b. Discount Factors over 6 years for various inflation/discount rates. A 4. A PVC pipe for water transport is manufactured by Company A. This extruded pipe has a nominal outer diameter of 25 cm and the drawing specifications state that this diameter should be 25cm ± 0.4cm. As part of a Quality Control regime, the pipe is regularly inspected for compliance to this requirement. Inspections involve diameter measurements on sample batches of 10 pipes. For each sample batch, the average diameter and range of diameters are to be found. Table Q A 4 gives details of the measurements for 8 successive sample batches. Sample Batch 10 x DIAMETER (cm) 1 24.7 25 24.7 24.9 24.9 24.8 24.9 24.9 24.6 24. 9 2 25 24.9 24.9 25 25 25.1 25 24.9 24.8 24.7 3 24.6 24.6 24.7 25 24.9 24.9 25 24.7 25 25.1 4 25 24.6 24.8 25 25 24.7 24.8 25 25 24.9 5 25.4 25.5 25.4 25.5 25.6 25.5 25.7 25.7 25.6 25.4 6 25.3 25.4 25.5 25.6 25.6 25.5 25.6 25.6 25.4 25.4 7 25.6 25.7 25.6 25.7 25.6 25.6 25.4 25.3 25.2 25.6 8 25.5 25.6 25.3 25.5 25.5 25.5 25.4 25.5 25.6 25.6 Table QA 4. QC data for extruded pipe. Discoun t Factors for given discount (inflation) rates over a 6 - year project Years 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 1 0.9901 0.9804 0.9709 0.9615 0.9524 0.9434 0.9346 0.9259 0.9174 0.9091 2 0.9803 0.9612 0.9426 0.9246 0.9070 0.8900 0.8734 0.8573 0.8417 0.8264 3 0.9706 0.9423 0.9151 0.8890 0.8638 0.8396 0.8163 0.7938 0.7722 0.7513 4 0.9610 0.9238 0.8885 0.8548 0.8227 0.7921 0.7629 0.7350 0.7084 0.6830 5 0.9515 0.9057 0.8626 0.8219 0.7835 0.7473 0.7130 0.6806 0.6499 0.6209 6 0.9420 0.8880 0.8375 0.7903 0.746 2 0.7050 0.6663 0.6302 0.5963 0.5645 For the “Average Control Chart”, the Control Limits are 25cm ± 0.2cm and the Drawing Limits are 25cm ± 0.4cm. For the “Range Control Chart”, the Control Limit is 5mm and the Action Limit is 8mm. (a) Calculate (i) the average and (ii) the range for each sample batch. ( 10 marks) (b) Plot the average and range control charts showing the appropriate limits on each. ( 10 mar ks) (c) Comment on the Quality implications of the data you have analysed. ( 10 marks) A 5 The “Economies of Scale” equation may be written as: C 2 = C 1 x (Q 2 / Q 1 ) n where C 1 is the known cost of a previous project, C 2 is the cost of a new (large r) project, Q 1 is the SIZE of the first project and Q 2 is the SIZE of the new project. The index, n, is a term which governs how economies of scale apply. If your original manufacturing project cost £1,034,564 , how much would a new manufacturing project 3 times the size cost if n = 0.6? (1 5 marks) PART B: CES Exercises on Manufacturing B1. Compare the manufacturing processes of (i) manual green sand casting and (ii) gravity die casting in terms of their respective economics. The component to be manu factured is 20cm in length and possesses a mass of 500g. It is to be manufactured from a cast aluminium alloy of price £1.75 per kg . Use CES (Edu Level 3) to generate plots of Cost per Unit (£) - v - Batch size (No of units produced) for each process simil ar to that shown below: Use the UPPER bound as your line for the basis of comparison . This helps avoid ambiguity in data analysis and interpretation. The full set of assumptions on which you should base your plots is as follows: Economic Factor Value Capital Write - Off Time (y r) 5 Component Length (m) 0.2 Component Mass (kg) 0.5 Discount Rate (%) 5 Load Factor 0.5 Mat erials Price (£/kg) 1.75 Overhead Rate (£/hr) 75 Tasks: (i) Manually extract sufficient data points from your CES - generated plots (remember to use the UPPER line of each plot for your own data set to avoid ambiguity). (ii) Enter the data into Excel in the following format , or similar : Batch Size Cost per Unit (£) Die Casting Sand Casting 1 ? ? 10 ? ? 100 ? ? 1000 ? ? 10000 ? ? 100000 ? ? 1000000 ? ? 10000000 ? ? (iii) Using Excel, plot Cost per Unit (y - axis) - v - Batch Size (x - axis) show ing both die casting and sand casting on the same graph. Use LOG scales for both sets of axes. Label and title all graphs appropriately. (iv) Report on your results. Discuss the comparative economics of the two competing processes in terms of: (a) the SHAPE of the graph (i.e. why is it this shape?) (b) Determine the batch size at which the cost per unit is identical for both processes. (c) Explain why the unit component cost is cheaper for one process at low batch sizes while cheaper fo r the other process at larger batch sizes. Use as many of the economic factors used (in the assumption table above) as necessary to help your explanation. (50 marks) B2. Two alternative methods of producing shafts for automotive applications are (i) hot metal extru sion (for metal shafts) an d (ii) filament winding (for fibre composite shafts) . Hot Metal Extrusion In HOT EXTRUSION, a compressive force is applied to a metal billet to force it to flow through a shaped die. There are two methods: direct extrusion, in which the die is stationary and the metal is forced through it by a moving ram. In indirect extrusion, the die itself compresses the stationary billet. The advantage of indirect extrusion is the lower friction between the billet and the container, resulti ng in lower extrusion forces, but the equipment is more complex and the product length is restricted. Hot extrusion is limited to ductile metals with room temperature hardness below 6 GPa and melting points below 2000K. A variant of the process - hydrost atic extrusion - may be used with brittle materials. The process is frequently subject to lower tolerances due to effects of heat and die wear. Better tolerances can be achieved by cold drawing as a secondary process. Steels usually require a molten glas s lubricant (Sejournet process). Rolling is frequently more economical for suitable, simple shapes and large production runs. Process schematic _ Filament Winding In FILAMENT WINDING, axisymmetric parts are produced by winding the resin - impregnated reinforcement (rovings or tape) on a rotating mandrel. The winding pattern could be helical, hoop or polar depending on the application. A multi - axis winding spindle could be used for winding more complex shapes. Winding is continued until the desired ma terial thickness has been achieved. The component is pulled off the mandrel as soon as it has hardened. The high reinforcement content of the process results in products with high strengths. The mandrel is made of either steel or plaster. Process schemat ic Background Two candidate materials for the shaft are compet ing here. The metal shaft will be made using a wrought aluminium alloy. The composite shaft will be prepared using a glas s fibre / polyester resin combination. The choice of material will determine the manufacturing process employed (i.e. one of the above two processes ) . Tasks (i) The process economics for hot metal extrusion and filament winding have been calculated as follows: Batch Size (n) Unit Cost (£) Unit Cost (£) Hot Metal Extrusion Filament Winding 1 10021.6 1021.7 10 1021.6 121.7 100 121.6 31.7 1000 31.6 22.7 10000 22.6 21.8 100000 21.7 21.7 1000000 21.6 21.7 10000000 21.6 21.7 Plot these data on a single set of axes (use log axes) of Unit Cost (y - axis) - v - Batch size (x - axis). Which process would you choose for small (10,000 shafts) production runs? Comment on your choices. (ii) Your planned production run is ≥ 10,000 shafts . You have been instructed to take environmental impact issues of your choice into account as well as the process economics. Use the “Eco - Audit” tool in CES to compare the energy and CO 2 impacts of the 2 possible material / process choice s. Base your environmental impact assessments on the following data . Materials i) A wrought aluminium alloy (Al 6061 in T4 condition). Find the alloy in CES via the “Material Universe” route, Metals and Alloys / Non - ferrous / Aluminium / Wrought / 6000 series / 6061 / T4) ii) A glass fibre / polyester resin composite of 75/25 w/w respective composition (find in CES via the “Material Universe” rou te, Hybrids...../ Composites / Polymer Matrix / Polyester / Unidirectional fibre / Filament wound ± 60⁰). Eco - Variable Inputs Use inputs to the eco - audit tool as per the following screenshots: ï‚· Generate plots of energy and CO 2 impacts for each stage of the shaft life cycle. ï‚· Which shaft material/process would you sel e ct if you we re seeking to minimi se overall environmental impact (HINT: look at the environmental impact situation both with and without consideration of “ End - of - Life Potential” )? ï‚· Justify your answers