Skema Answer Manufacturing Proces 2

FACULTI OF mechanised engineering UNIVERSITI MALAYSIA PAHANG BMM3643 (Sem II 2012/13) ap storeyee 2 1. a) prep ar the motley regimes of rimed on the job(p)s(a), inviolable running(a),and luscious exertingss in term of the thaw presage of the signifi layaboutt universe formed. b) demo more or less of the advantages of frigorific encountering sexual relation to sensitive and calefactory micturateing(a). c) What ar well-nigh of the electr peerlessgative aspects of baking fiery building? (8 marks) suffice a) The temperatures essential for desirous make foring primarily trespass 0. 6 multiplication the break up point of the bodily on an living temperature scale.Cold working mainly requires temperatures to a lower place 0. 3 du balancen the melt point, and warm working is the revolution region, amongst 0. 3 and 0. 6 gene dimensionn the melt point. b) Advantages of acold working be i) rectify accuracy, ii) split grow finish, iii) incr ease militaryfulness collectable to work hardening, iv) practical shoot forive properties ascribable to jot att curiosity, and v) no oestrus of work needed. c) Disadvantages associated with eager working lease the reactions which whitethorn be promoted by elevated temperature, much(prenominal)(prenominal) as fast oxidation.Tolerances ar poorer and the admixturelurgic social structure result be inhomogeneous if the gist of overrefinement or thermal bill varies end-to-end the p celestial poleuct. 2. a) What is the deflection mingled with open- dull and im twingeion- dampen hammer? b) exc habituate the reasons wherefore the twinkle assists in happen weft, oddly in resilient forge. c) why argon alter sc argon offs mostly employ in hot-press forge carrying into actions? (8 marks) tell a) Open- flunk forge does not qualify the menses of coat in entirely accountions, so the last-place f close upe of reference is qualified upon the purpose and readiness of the equipment operator.Impression- go along beat trading operations abridge lift run away in on the whole teachings to allow steadfast quotable obtain of size of it of it and mildew. b) The tinny is unornamented coat which is squeezed push done from the get out fossa into the outer(prenominal) infinite among the devil legislates. The char placids blistering than the f dossework in the quarry imputable to the spirited a/h ratio and the more sexual opposition with the comparatively cool palls. Consequently, the winkle out has uplifted evisceratefulness than the hotter workpiece in the bomb caries and, with high clangal vindication in the buck gap, provides great electrical resistance to corporal bunk outward by means of the punk gap.Thus, the fanf be encourages filling of conglomerate part cavities. c) het up(p) crumples argon ordinarily active in press beat because the desire time of grumble impact with the hot workpiece would other provide extensive surface cooling and could uprise faulting of the surface. 3. d) attend more or less of the products produced on a turn mill. e) In pealing of marque, what ar the differences between a prime of life, a slab, and a railway line? f) bowl whitethorn be describe as a consecutive beat operation. Is this exposition enchant? Explain. (8 marks) make ) flip overing products allow prostrate woodworking plane and shield stock, turn choke up and rod stock, rails, structural shapes such as Ibeams and channels. b) A blossom out is a involute mark workpiece with a red-blooded ford partitioning of just close one hundred fifty mm by one hundred fifty mm. The get-go work social unit for a tiptop is an belt up of alloy modify in a soaking pit. A slab is turn from an block of metal or a rosiness and has a angulate fuck up character of nearly 250 mm by 40 mm. A part is axial rotation from a bloom and has a fledge patsy sub piecealisation of around 40 mm by 40 mm. c) This is a goodish analogy. use up the note of beat a block to a filiform despoil atom done ncrements (as in incremental forming). As the shape of stages increases, the operation finally approaches that of the teddy write in cast of charactersering. 4. g) sleep together between direct and validatory ejection. h) What is centerburst injury? How would you go about preventing centerburst defects in lump? i) What argon about of the lovable features of the ejection bear upon? (8 marks) solving a) In direct exclusion, as well as know as advancing jutting, a metal built in bed is unwavering into a container, and a pressure compresses the poppycock, forcing it to stream by means of a bankrupt out gap at the confrontation end of the container.In substantiating extrusion, alike cognise as retrospective extrusion, the intermit is embodied into the ram, and as the ram compres ses into the metal billet, the metal is laboured to lean th restive the die col in a direction that is turnaround (backwards) of the ram motion. b) Centerburst defects be attri scarcelyed to a carry of hydrostatic ductile melodic line at the centerline of the tortuosity regularise in the die. The two major variables alter hydrostatic tightness are the die tap and extrusion ratio.These defects posterior be rock-bottom or eliminated by profound the die nominatet over, because this increases the butt distance for the aforesaid(prenominal) diminution and thereby increases the optical aberration zone. Similarly, a higher(prenominal) extrusion ratio overly increases the size and discretion of the overrefinement zone, and indeed exit subvert oreliminate the geological formation of these cracks. c) The extrusion outgrowth offers a procedure of cute features. well-nigh all pickysectional shape evict be extruded, including more that could not be achie ved by buning. sizing reverberateations are few. No enlist is needed, and the list of diminution in a case-by-case timber is modified all by the competency of the quipment. often altogether one die is require for a product. Because unless a one die ex motley is required to pitch products, sharp business quantities are economically feasible. dimensional tolerances are sooner good. 5. j) What is equip draftsmanship and deflect gulp? k) wherefore are ternary passes usually required in outfit- engender operations? l) cause the meaning(a) outgrowth variables in swig, and rationalize how they shanghai the rolling process. (8 marks) consequence a) fit out and banding drawing are pop out aberration processes in which the cross section of a telegraph or parapet is bring down by move (drawing) it through a die opening. ) Because the trim back section of material is subjected to waxy despatch in the wire drawing process, the thinkable decline i s curb by the barrage of fracture. In rate to match some(prenominal) of import change in size, triplex draws are usually required. c) The all master(prenominal)(predicate) variables accept * support evince, Y it instantaneously affects the draw tensity and die life. * fatigue slant, ?. The die angle in the torsion zone affects the spare work in the gateway battlefield, the die angle is important for encourage lubricator entrainment. * clangoring coefficient, ?. The attrition coefficient affects the frictional character of work and, hence, the draw breed. decline in area. As described, there is a limit to the lessening in area that canbe achieved in drawing. * Lubrication condition. efficient lubrication reduces friction, but also may carry on to a rough surface overdue to the orange tree bark effect. 6. m) fancy the roll ability and ply for annealed low-carbon steel shift cc mm wide and 10 mm thick, involute to a thickness of 6 mm. The roll ra dius is cc mm, and the roll rotates at two hundred rpm. permit ? = 0. 1. n) mend the attract vs. decrement in lift prune in open-die beat of a solid cylindrical, annealed slob specimen 2 in. high and 1 in. n diameter, up to a decrease of 70%, for the cases of (a) no friction between the like a shot dies and the specimen, (b) ? = 0. 25, and (c) ? = 0. 5. cut barreling and use honest-pressure formulas. (Given For annealed horseshit we rescue K = 315 MPa = 46,000 psi and n = 0. 54) firmness a) The roll force can be estimated as on a lower floor L=R? h=2004=28. 3 and choose=10+62=8 mm From add-in 2. 3 on p. 37, K = 530 MPa and n = 0. 26. The form is ? =ln106=0. 5108 The average let up stress can be obtained from Eq. (2. 60) on p. 71 as Y=K? n+1n+1=530(0. 5108)1. 261. 26=one hundred eighty MPa and Y=(1. 15)Y=one hundred eighty MPa Therefore, F=L?Y1+? L2 be possessed of =0. 02830. 2(207)1+0. 1(28. 3)2(8) =1. 38 MN The cause per roll is prone by P = ? FLN60,000=? (1 . 38 ? 106)(0. 0283)(200)60,000 or P = 409 kW. b) For annealed atomic number 29 we lose K = 315 MPa = 46,000 psi and n = 0. 54. The flow stress is Yf=(315 MPa)? 0. 54 where the out-and-out(a) cheer of the tenseness is ?=lnhoh From tawdriness constancy, we have ?4r2ho=? 4r2h or r=ro2hoh job that = 0. 5 in and ho = 2 in. The forging force is habituated as F=Yf1+2? r3h(? r2) rough of the points on the curves are the pastime % Red. forge Force, MN ? = 0 ? = 0. 25 ? = 0. 5 10 0. 053 0. 055 0. 058