structure comes from local suppliers. small rates Dangerous operation Casting Die casting alloys are normally non-ferrous and there is a large number available with a wide range of physical and mechanical properties covering almost every conceivable application a designer might require. Aluminum and zinc alloys are the most widely used. First, the mould is sprayed with lubricant and closed. This lubricant helps control the temperature of the die and assists in the removal of the casting. Molten metal is then injected into the die under high pressure. Die preparation Filing Ejection Shakeout Inserts can be cast-in (such as threaded inserts, heating elements, and high strength bearing surfaces). Reduces or eliminates secondary machining Rapid production rates. Casting tensile strength as high as 415 (60 ksi). Casting of low fluidity metals. The main disadvantage to die casting is the very high capital cost. Both the casting equipment required and the dies and related components are very costly, as compared to most other casting processes. Therefore to make die casting an economic process a large production volume is needed. Turing are simple abstract computational devices intended to help investigate the extent and limitations of what can be computed. In preparing the machine, users will be expected to select the appropriate work holding devices, and to mount and secure Turning produces solids of revolution which can be tightly toleranced because of the specialized nature of the operation. Turning is turning All materials Very good tolerances Short lead Limited to rotational parts Part may require several operations
them to the machine spindle. Users will be required to select the appropriate cutting tools, to mount and secure them to the appropriate tool holding devices, and to place the cutting tools in the relevant positions within the tool posts , turrets ,slides or tools in the relevant positions within the tool posts , turrets ,slides or tool change magazine/carousel, where this applicable performed on a machine called a lathe in which the tool is stationary and the part is rotated. The figure below illustrates an engine lathe. are designed solely for operations, so that precise control of the cutting results in tight tolerances. The work piece is mounted on the which rotates relative to the stationary tool. times operations and machines High equipment cost Significant tool wear Large amount of scrap Milling is the most common form of machining, a material removal process, which can create a variety of features on a part by cutting away the unwanted material. The milling process requires a milling machine, workpiece, fixture, and cutter. The workpiece is a piece of pre-shaped material that is secured to the fixture, which itself is attached to a platform inside the milling machine. The cutter is a cutting tool with sharp teeth that is also secured in the milling machine and rotates at high speeds. By feeding the workpiece into the rotating cutter, material is cut away from this workpiece in the form of small chips to create the desired shape. It is compatible with all materials Flexible use Short lead times The milling process, those that are present can often be attributed to inaccuracies in a features dimensions or surface roughness. In short, the use of an inadequate milling machine, a dull cutting blade or failure to secure the work piece in question is the biggest problems manufacturers face when implementing
the process. The chips must exit out of the hole created by the cutting. Chip exit can cause problems when chips are large and/or continuous. The drill can wander upon entrance and for deep holes. For deep holes in large workpieces, coolant may need to be delivered through the drill shaft to the cutting front. Once the drill site has been selected and surveyed, a contractor or contractors will move in with equipment to prepare the location. If necessary, the site will be cleared and leveled. A large pit will be constructed to contain water for drilling operations and for the disposal of drill cuttings and other waste. A small drilling rig, referred to as a dry hole differ, will be used to start the main hole. A large diameter hole will be drilled to a shallow depth and lined with conductor pipe. Drilled holes are characterized by their sharp edge on the entrance side and the presence of burrs on the exit side (unless they have been removed). Also, the inside of the hole usually has helical feed marks. Help learners master materials at their own pace. Good drill and practice provides feedback to students, explains how to get the correct answer, and contains a system to keep track of student progress. They can be used to build confidence as more answers are correctly provided For most students, it's boring, and Lacks the that "hands-on learning" provides, and It has no application in the student's i.e. rarely will the student make the connection with why these things are important moulding Plastics bottles and containers of all sizes and shapes e.g. fizzy drinks bottles and shampoo bottles Polymers used: HDPE, LDPE, PET, PP, PS, PVC Hollow thermoplastic tube is extruded between a split mould and clamped at both ends Hot air is blown to the parison which expands it to take the shape of the mould Once cooled product is ejected by opening the split mould Intricate shapes can be formed Can produce hollow shapes with thin walls Ideal for mass production High initial set- up cost because the mould is expensive
Abrading Filing Grinding A bench grinder. A grinding disk. Sanding Emery cloth 6 Heat treatment p60-61 CHARACTERISTICS PREPARATION PROCESSES ADVANTAGES PICTURE annealing and tempering • The metal is heated (Not to ‘red hot’) (1) • The temperatures are signified by the changing colour of the metal when heated (1) • The metal is then quenched in water (1) • retain a sharp edge (1) • harder than the material to be cut (1) • reduce wear (1) • It is tempered to remove some of the brittleness / hardness / to increase the toughness of the blade (1) making the blade more flexible / reduce the chances of it snapping / withstand impact (1) hardening. 7. Conversion and Seasoning p62 conversion and through (slab sawn)
Customers Benefits • customers receive products that are higher standard/reliable (1) • customer satisfaction with service/product improved as less breakages/better service (1) • customer reassured by quality of organization (1) Quality Control monitor/check/test product at specific points. Quality control is that part of Quality Assurance that involves inspection and testing of a product either during or immediately after production. Quality control refers to the procedures carried out by a quality inspector at certain stages during manufacture. Quality control tests are typically conducted after each process of manufacture and/or after complete assembly/completion of the product. Tolerances (acceptable amount by which a product’s size or other feature can differ from that stated in the specification) are set for products/components and these are that standards to which the QC inspector checks the products/components. E.g. Checking size Checking weight Checking function Checking that a surface is level There is 100% inspection where all units in the batch are inspected, normal inspection where a sample is inspected, the sample is determined by the sampling plan, and reduced inspection which is like normal inspection, but uses a smaller sample size and is more economical. Computer aided inspection uses a CMM (coordinate measuring machine) to measure dimensions. This is a faster, more accurate way of measuring dimensions. Laser scanning systems are also used; they create a 3D model of the part. Testing takes place in a lab after the product has been manufactured. Testing is concerned with the product’s performance. Non destructive or failure testing is when the product is tested until it shows signs of breaking to determine how much force is needed to deform it. Destructive testing is when the product is destroyed while being monitored so that data can be gathered about the product, e.g. car crash testing with crash test dummies. Testing to Destruction: Force is applied in one form or another till the products breaks • Product is tested in controlled conditions (1) • Force is applied until the product breaks(1) • Information is gathered on how much protection is gained (1) • Information is gathered on how much force is needed/limits of force at point of destruction (1) • Information is gathered on how the product behaves/breaks upon breaking (1)