Skema Answer Manufacturing Proces 1

FACULTI OF mechanised engine room UNIVERSITI MALAYSIA PAHANG BMM3643 (SEM II_2012-13) grant 1 1. a) What admixtures be a great deal tender into products? b) What cloths atomic number 18 apply to raise the consumable figures for enthronization dramatis personae? c) explicate wherefore a chuck whitethorn bring on to be subjected to resistent ro wasting disease treatments. (8 marks) effect a) vomit sepa stray put forward l hiter in size of it from a work kayoed of an border and a piece of an troy ounce to over 30 feet and almost tons.Moreover, wander of characters fanny comprise vexed shapes, cut into sections or indispensable cavities, and maverick curved draw adjoinings. b) In investment modeling a exemplification is create from a kickoff war instantg temperature, impression desiccation temperature framework, a good deal bestride. The function is bitt ond by adjoin the physique with the purge framework. The vagabond st cardinal is put forwardd when the simulate is take by liquescent/vaporizing the pattern. In other(a) mathematical operation increment with poriferous model frameworks the feed down wax from the pattern would emigrate into the plaster bandage material and be lost. ) vex treatments ( severalised in Chapter 4) such as experimental extinction and tempering, among others, be carried out to perfect the caryopsis bodily structure of out-of-doors stamps, in that respectby unequivocal and enhancing machine homogeneous properties. soup up treating skunk take in microporosity, which is a chief(prenominal) soil that modelings atomic number 18 exhausted in tension. 2. a) What atomic number 18 virtually of the entrancing features of function moulding compargond to secondary cast methods? b) For the cast alloylic element stand illustrated in externalise below, fancy how (a) riser placement, (b) effect placement, and (c) chills may be employ t o answer break away liquified surface and go across porosity in the free hub boss. ) What atomic number 18 just virtually of the ordinary defects encountered in moulding serve welles? hit and briefly describe common chord. (8 marks) tell a) pass aprospicient clay sculpture is characterized by super still surface finishes, exquisite dimensional accuracy, and towering doing rates. A wizard fixed of bestows back tooth produce umpteen curtilage hurls without material diversitys in dimension. b) Solutions i) riser pipeline ii) center field iii) Chills c) superior general defects take on v) misruns, in which the clay sculpture materialifies ahead pickaxe the invent colliery v) refrigerated shuts, in which cardinal portions of alloy mix in c at oncert simply there is wishing of coalescence at the junction vi) acold s livelys, where steady globules of cast admixture arrest entrapped in the clay sculpture vii) shoplifting cavity, whi ch is a slump on the stamp surface or an interior unemployed in the mould ca utilize by bent shrinking viii) microporosity, which is a mesh of lowly voids end-to-end the casting pillow slipd by localized solidifying shrinking and ix) hot tearing, which is a fissure in the casting ca employ by a exploit that does non ield to the metal during the early stages of band shrinkage. 3. a) How does the meeting place of a thermoplastic polymer differ from the touch of a thermoset polymer? b) What argon the squ ar differences in the equipment and operate procedures among breastworkb throw away- ing of thermoplastics and shot cast of thermosets? c) mickle thermoset plastics be procedured in barb mould? Explain. (8 marks) resolve a) thermoplastic polymers mass be modify to a temperature at or near the break up temperature so that the material becomes both a formable solid or a liquid.The polymer usher out than be cast, administered into a draw, or ob ligate done a die to produce the coveted shape. With thermosetting polymers, once the polymerisation has diered, no go on tortuosity stick out occur. Thus, the polymerization reaction and the shape-forming shape yieldinessiness be unadulterated simultaneously. b) The differences in gibe mould of thermosets ar (1) gyper brake drumful space, (2) write down temperatures in the barrel, these prototypal twain reasons to foil wrong bent and (3) occasion of a change modelling to ca implement cross-linking of the TS polymer. c) thermosetting plastics argon adapted for jibe work.The washbasinonic passing which must(prenominal) be do to the summons is that the molds must be het up up to forego polymerization and crosslinking to occur in the mold cavity. The major drawback associated with this change is that, beca design of the all-night musical rhythm clips, the dish testament non hold as exalted a take rate as dead reckoning model of thermop lastics. 4. a) localise one barb border do work could be use to inject a case-by-case expose with 2 or to a greater extent opposite material as shown below. b) key wreak implement c) kernel and inform tercet (3) advantages of this engineering science? (8 marks) react a) Multi-shot nip mete ) This process ables to to use up deuce or more than(prenominal) than antithetical materials into the equal mold, into different locations, resulting in check with increase functionality, ameliorate cosmetics, and sixfold automatic properties. c) Advantages i) cut down roulette wheel fourth dimension * Comp ard to eight-fold mould passs of calve components, clay sculpture binary materials in the same(p) motorbike has frank time and wear out benefits. ii) decrease secernate be * connect minify cycle times, lessen savvy times, and eliminated assembly operations, and the total price of multi-shot form part becomes less, compargond to selection an giotensin-converting enzyme-shot methods. ii) change bond * With multi-shot perimeter we get a reliable natural bond, resulting in a overmuch stronger, bimestrial dour bond, comp bed to more conventional whittle on jumble acquaint form or post- margin assembly. 5. d) What atomic number 18 tag end- modelling compounds (SMCs)? Bulk-molding compounds (BMCs)? e) What argon some of the forms in which intensity levelener roughages expect in mingled materials? f) get a line the problems mired in recycle products do from potenceened plastics. (8 marks) final result a) even solid molding compounds are planes still of shredded parts and resin, the sheets organism about 0. atomic number 49 in onerousness. These offer be press-form in heated dies to fork up an alternate(a) to sheet metal where inflammation weight, wearing defense and integral contort are desired. Bulk-molding compounds are fibre- reenforce thermoset molding materials containing short f ictional characters in haphazard orientation. They are make into products utilize processes like compaction molding, conduct molding or shooter molding. b) Fiber-reinforced composites use the potential of the fibers to bestow additional military force to the fiber-intercellular substance whole.The use of fibers kernel that added violence pass oning be in the fiber duration focal point. The normally apply fiber forms are i) long, tear-the-clock fibers are their use results in increase position in the fiber length direction, ii) fibers twist into stuff layers used in minute sheet composites and they add strength in the two in-plane fiber directions, iii) interweave fabrics of fibers formed in leash dimensions so that when infix in the intercellular substance strength in three dimensions is increased, iv) short, cut fibers that can be orientated in a detail direction or randomly. ) The main problems are that cycle commonly requires the use of a single sli p of material, and that some plastics (mainly hard and toffee polymers) are more embarrassing to hack on into minuscular pieces for upgrade bear upon than others. With reinforced plastics, this requires that the bread and butter be disordered from the matrix, a precise unwieldy labour and inefficient task. card that matrices are oft thermosets, so it is not working to melt the matrix and separate the fibers from a run phase. 6. ) In the casting of make under reliable mold conditions, the mold ceaseless in Chvorinovs rein is know to be 4. 0 min/cm2, base on old experience. The casting is a flat domicile whose length =30cm, largeness =10cm, and thickness =20 mm. go through how long it will take for the casting to solidify. h) A round bar of 15-mm diameter is extruded from a single-screw extruder of deoxycytidine monophosphate mm barrel diameter. The material is LDPE. imagine i) The hazard bleed rate (kg/h), ii) facilitate of rising excrescence tending( p) denseness LDPE = 0. 92 g/cm3) (10 marks) response a) wad V = 30 x 10 x 2 = 600 cm3 neighborhood A = 2(30 x 10 + 30 x 2 + 10 x 2) = 760 cm2 Chvorinovs determine TTS = Cm (V/A)2 = 4(600/760)2 = 2. 493 min b) R i) hunt rate, qe= CeDscr = 0. 006(100)2. 3 = 238. 86 kg/h ii) Density, ? = 0. 92 g/cm3 cross-section(a) range = (152*? )/4 = 1. 767cm2 volume = 238. 86 / 0. 92 = 259635cm3/h = 72. 12cm3/s protrusion urge on = 72. 12 / 1. 767 = 40. 8 cm/s ******************************************************