Version 1.0 General Certificate of Education (A-level) January 2013 Design and Technology: Product Design PROD1 (Specification 2550) Unit 1: Materials, Components and Application Report on the Examination
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This paper performed as expected with students attempting all parts. The level of response was varied and questions dealing with polymers were generally more confidently answered than those dealing with metals. Administration There are still a significant number of candidates making use of additional sheets. The responses on the additional sheets very often merely repeat that on the original paper and in many cases do not result in further marks being awarded. Section A 1(a) 1(b) This question appeared to be surprisingly challenging for candidates with many failing to mention the link between the computer and the machine. A number of students discussed the advantages of CNC and/or made reference to cutting accurately rather than focussing on the definition of CNC. Responses to this question were mixed. Better responses named a suitable application, with the most common being CNC laser cutter, router or milling machinery. Reasons were then well linked to the stated application such as, repeated accuracy and speed of producing complex parts. 2 Most students were able to suggest a suitable product with supporting comments. The most popular products were furniture items. Better responses mentioned aspects such as, no grain issues as in natural timber, large sheet sizes not constricted by natural timber size. Marks were not awarded for generic terms such as, cheap, strong, easy to work with. 3 This was generally well answered with most students able to correctly match the equipment to the application. 4(a) 4(b) This question was primarily well answered with the most popular answers focussing on sanding of timbers and hot metal processes such as casting or welding. Leading on from the previous named process, students showed a good understanding of why there was a need for the safety precaution. 5 This question was not particularly well answered and, although a large number were able to identify the bonding risks with cyanoacrylate, many failed to elaborate on this. Higher level responses included reference to the use of UV light, the ease of wiping up spillage with water. Many lower level respondents were of the opinion that UV hardening needed to be exposed to sunlight. Section B 6(a) 6(b) Responses to this question varied from students demonstrating good use of technical language and linking this to product use, through to vague unexplained points. Better responses included references to aspects such as good compressive strength enabling the bench to take the weight of people, an appreciation of aesthetics such as the grey colour to suit the current urban style or how pigments can be added to alter the colour scheme. There were mixed responses to this question, with some accurate descriptions of producing the mould and bench, through to variations of sand casting, pressure die casting and injection moulding. The better responses discussed mixing constituent parts, manufacture of moulds with aspects such as removable panels, pouring the concrete, removal of air pockets, smoothing the surface and setting time. Poorer ones often referred to cement and discussed aspects such as heating the mixture to make it set. 3
6(c) 7(a)(i) 7(a)(ii) 7(b) 8(a)(i) 8(a)(ii) 8(a)(iii) 8(b)(i) 8(b)(ii) 8(c) The mark scheme allowed a range of possible modifications. Most popular responses considered the use of rebar or the addition of a central leg to spread the load. The answers for the nickel plated pencil case were not answered as well as HIPS in question 7(a)(ii) and this may indicate that metal is an area for centres to focus on. Some students tended to state what the material should do, rather than why the material is appropriate. There were also some students who wasted time by describing how the pencil case would be manufactured rather than material properties linking to suitability for the manufacture process. Again generic statements such as, strong and withstand wear and tear were a feature of lower level answers. The better responses made reference to factors such as, malleability for press forming the shape, as well as the nickel acting as a sacrificial layer preventing the steel from rusting. The properties of HIPS were generally well linked to product use and good points were made regarding HIPS chemical resistance allowing it to be used with shaving products, impact resistance when dropped in sink and, as a thermoplastic, its ability to be injection moulded to produce the complex 3D body shape. Weaker answers tended to include nonspecific statements such as, good strength to weight ratio, cheap and easy to mould. The majority of students gave appropriate reasons for using cellulose acetate. Many considered the transparent nature of the material allowing the consumer to view the food product, the material s chemical resistance and food safe nature. Lower attaining answers referred to the cheap nature of the material and there was some confusion between biodegradable and recyclable. Almost all students were able to suggest a suitable material, with MDF and plywood being the most popular. Most students scored half marks or below on this question. Many of the reasons for the material s use were nonspecific such as, can be easily cut, cheap, strong, comes in many shapes and sizes. The better answers described how the material could be cut easily with a jigsaw to produce the curved shape as well as the smooth, flat surface making it suitable for painting. Good comparisons were made to natural timbers in terms of cost, board size, lack of defects etc. The most popular reason for using acrylic was its transparent nature, allowing people to see that it was a collection box or for staff to establish when the box needed to be emptied. Generic statements were again evident in the lower level answers with strong to protect the money and cheap being amongst the more frequently proposed. The mark allocation was largely in the lower marks breakdown as most students offered quite generic descriptions and used non-technical language. A number referred to a CNC machine rather than a specific machine such as a CNC router. There were a number of candidates who described at length how to use the proposed tooling rather than how to make the product. Higher attaining responses used detailed notes and diagrams showing detail such as the use of a template, band saws and jigsaws to cut out the parts as well as specific joining methods such as dowel joints. They also included aspects such as tessellation of parts and cutting rebates or using screws to join the acrylic panel. This question revealed a lack of understanding of the term fabrication. While some students were able to identify that this was appropriate for a one-off product they failed to consider why this was relevant. The better responses considered factors such as tooling set up costs and one off production, the ability for the product to be manufactured with basic tools, where separate pieces could then assembled on site. Most students attained half marks for this question and this was primarily due to the lack of detail in responses. A number of students still incorrectly refer to spray 4
painting as a specific finish and a range of inappropriate finishes were proposed including powder coating and electrostatic painting. Some chose to outline the advantages of the finish. Acrylic paint was the most popular finish proposed and higher attaining students described preparing the surface by sanding, applying primers or undercoats as required using brushes, rollers or spray application, using even layers and sanding off high spots. 8(d) Answers to this question were varied in nature and a number of students elected to redesign the product rather than develop the original giraffe design. The best answers modified the giraffe by including features such as coin runs, activation of animal sounds or a thank you message when the donation was made. They also included features such as a seat or area for photos, lower money slots for children to place coins, a moving tail, money drop shelf similar to an arcade game and facts about animals or a quiz incorporated into the spots. Better respondents also discussed the use of marine ply or HDPE sheets as well as the use of templates and jigs to aid batch production. Lower level respondents did not tend to address the batch production aspect or suggested mass production techniques such as injection moulding. Mark Ranges and Award of Grades Grade boundaries and cumulative percentage grades are available at www.aqa.org.uk/over/stat.html The UMS conversion calculator can be found at www.aqa.org.uk/umsconversion 5