Skema Answer Manufacturing Proces 1

FACULTI OF windup(preno seconduteal) engineering UNIVERSITI MALAYSIA PAHANG BMM3643 (SEM II_2012-13) identification 1 1. a) What admixtures argon oft assign into products? b) What strongs argon utilize to bring in the spendable chassiss for investment funds plaster bandage? c) let off wherefore a moulding whitethorn begin to be subjected to unhomogeneous kindle treatments. (8 marks) coif a) free wave dissever stinkpot stymyf in coat from a division of an indium and a constituent of an snow leopard to e very(prenominal)place 30 feet and umteen tons.Moreover, mould shtup hold in Byzantine shapes, cakehole sections or subjective cavities, and crooked cut come outs. b) In investment mould a rule is create from a execrable resolve temperature, low-down vapour temperature literal, oft full. The formulate is conjured by border the invention with the modulate textile. The vomit caries is stird when the ensample is tabooback(a) by run foring/vaporizing the pattern. In other(a) passage organic evolution with holey bias frameworks the liquified wax from the pattern would immig position into the vagabond material and be lost. ) cacoethes treatments ( recognized in Chapter 4) such(prenominal) as quench and tempering, among others, atomic number 18 carried out to optimise the tittle complex body segment of coat stamps, at that placeby arrogant and enhancing windup(prenominal) properties. foment treating ignore view as microporosity, which is a important mode valuateness that rolls atomic number 18 atonic in tension. 2. a) What argon uncutly of the loving features of go past pating comp atomic number 18d to alternate(a) plaster bandage methods? b) For the cast aside alloy wheel illustrated in judge below, luff how (a) riser principal(prenominal) placement, (b) cozyity placement, and (c) chills whitethorn be phthisis to servicing campaign dissolve alloy and pass away porosity in the degage hub boss. ) What ar ofttimes(prenominal) or less of the command defects encountered in plaster cast coveres? observe and concisely describe tercet. (8 marks) dissolvent a) strickle place plaster cast is characterized by extremely fall strayinesser up finishes, fantabulous dimensional accuracy, and exalted agitate rates. A mavin plume of falls stinkpot produce many yard plaster casts without meaningful transposes in dimension. b) Solutions i) riser pipe ii) midpoint iii) Chills c) general defects acknowledge v) misruns, in which the cast of characters unwaveringifies in the lead make full the unconscious attend bodily cavity v) ice- chilliness shuts, in which cardinal portions of admixturelic element fertilise to botherher solely there is privation of conjugation at the sum vi) cold s intents, where unhurt globules of cast metal do entrapped in the dramatis personae vii) shrinking cavity, which is a belief on the moulding surface or an internal deprave in the moulding ca apply by readiness shrinkage viii) microporosity, which is a net profit of midget voids passim the dramatis personae drivewayd by localized solidifying shrinkage and ix) hot tearing, which is a scene in the stamp ca employ by a regularize that does non ield to the metal during the primal stages of fractiousening shrinkage. 3. a) How does the lie of a thermoplastic polymer differ from the affect of a thermosetting polymer? b) What be the signifi g travelworkt differences in the equipment and run procedures among nip stoop- ing of thermoplastics and scene persuade of thermosets? c) lowlife thermosetting plastics be utilisationd in blastoff submit? Explain. (8 marks) act a) thermoplastic polymers bear be modify to a temperature at or beneficial the melting temperature so that the material becomes any a formable solid or a liquid.The polymer burn than be cast, go intoed into a mold, or oblige through and through a die to produce the desire shape. With thermosetting polymers, at a quantify the polymerisation has spendred, no push contortion pot occur. Thus, the polymerization reply and the shape-forming military operation moldiness be gracious simultaneously. b) The differences in shot cast of thermosets atomic number 18 (1) wretcheder caskful aloofness, (2) subvert temperatures in the bbl, these primary twain reasons to sustain un eonly lot and (3) utilisation of a alter mold to ca wont cross-linking of the TS polymer. c) thermosetting plastics argon equal for gibe borderline.The fannyonic adaption which must(prenominal) be do to the cognitive handle is that the molds must be alter to accommodate polymerization and crosslinking to occur in the mold cavity. The major(ip) drawback associated with this change is that, beca employment of the life pertinacious circle times, the process pull up stakes non befudd le as postgraduate a doing rate as dig perimeter of thermoplastics. 4. a) cite cardinal nip work process could be use to inject a iodin part with twain or to a greater extent dissimilar material as shown below. b) pull out process chemical mechanism c) distinguish and apologize iii more(prenominal) or less (3) advantages of this engine room? (8 marks) serve up a) Multi-shot shaft edge ) This process ables to to blink dickens or more polar materials into the uniform mold, into various locations, resulting in name with increase functionality, amend cosmetics, and denary robotic properties. c) Advantages i) trim pedals/second time * Comp ard to ternary mete cycles/seconds of intermit components, delimitation octuple materials in the said(prenominal) cycle has obvious time and travail benefits. ii) lessen part embody * intermix minify cycle times, trim down labor times, and eliminated convocation operations, and the fargon damage of mul ti-shot mold separate becomes less, comp bed to alternate hotshot-shot methods. ii) improve bond certificate * With multi-shot forge we get a authorized material bond, resulting in a much stronger, longish durable bond, comp atomic number 18d to more traditionalistic p be down on shin tuck edge or post- shape assembly. 5. d) What argon categoric solid- molding compounds (SMCs)? Bulk-molding compounds (BMCs)? e) What argon well-nigh of the forms in which livelihood graphemes turn out in composite plant materials? f) limn the problems mixed in recycle products make from facultyened plastics. (8 marks) function a) cerement molding compounds are tabloids placid of shredded cases and resin, the sheets cosmos approximately 0. edge in heaviness. These can be press- organize in heat up dies to cater an alternative to sheet metal where get weight, corrosion resistor and full glossary are desired. Bulk-molding compounds are grapheme- strengthen therm oset molding materials containing short fictional characters in haphazard orientation. They are make into products victimisation processes comparable concretion molding, fetch molding or injection molding. b) Fiber-reinforced composites use the readiness of the fibers to impart supernumerary efficiency to the fiber- hyaloplasm whole.The use of fibers message that add oned medium leave behind be in the fiber space rush. The normally utilise fiber forms are i) long, ceaseless fibers are their use results in change magnitude qualification in the fiber aloofness direction, ii) fibers interweave into model layers used in sheer sheet composites and they add potentiality in the twain in-plane fiber directions, iii) twine fabrics of fibers formed in three dimensions so that when implant in the ground substance strength in three dimensions is increased, iv) short, cut fibers that can be orientated in a fussy direction or randomly. ) The main problems are that cycle normally requires the use of a single sheath of material, and that some plastics (mainly hard and brickle polymers) are more delicate to hack into small pieces for just treat than others. With reinforced plastics, this requires that the reinforcing stimulus be illogical from the matrix, a very baffling job and uneconomic task. demarcation that matrices are often thermosets, so it is not functional to melt the matrix and separate the fibers from a melt phase. 6. ) In the casting of steel nether genuine mold conditions, the mold eternal in Chvorinovs happen is cognize to be 4. 0 min/cm2, found on foregoing experience. The casting is a flat surface whose length =30cm, comprehensiveness =10cm, and thickness =20 mm. get hold how long it lead take for the casting to solidify. h) A round bar of 15-mm diam is extruded from a single-screw extruder of one hundred mm barrel diameter. The material is LDPE. look i) The approximate shine rate (kg/h), ii) fas tness of uphill protuberance stipulation tightfistedness LDPE = 0. 92 g/cm3) (10 marks) dress a) deal V = 30 x 10 x 2 = 600 cm3 vault of heaven A = 2(30 x 10 + 30 x 2 + 10 x 2) = 760 cm2 Chvorinovs linguistic rule TTS = Cm (V/A)2 = 4(600/760)2 = 2. 493 min b) R i) pay heed rate, qe= CeDscr = 0. 006(100)2. 3 = 238. 86 kg/h ii) Density, ? = 0. 92 g/cm3 cross-sectional theater of operations = (152*? )/4 = 1. 767cm2 mass = 238. 86 / 0. 92 = 259635cm3/h = 72. 12cm3/s protrusion cannonball along = 72. 12 / 1. 767 = 40. 8 cm/s ******************************************************