ir YABA COLLEGE OF ‘TECHNOLOGY, YABA. LAGOS. SCHOOL OF ENGINEERING. MECHANICAL ENGINEERING DEPARTMENT. sl E SION EXAMINATIONS. COURSECoDE /trTy TECOND SEMESTER 2020 / 2024 ACADEMIC SESSION PASE 1 (py -E: MEM 423 - PRESS AND CUTTING TOOLS MECHANICAL ENGINEERING, (MANUFACTURING OPTION). ‘TIME: 3 HOURS. MATRICULATION UMBE aa INSTRUCTIONS NUMBER OF STUDENT: : 1. ATTEMPT ANY FIVE (5) QUESTIONS FROM THE AVAILABLE SEVEN (7) QUESTION: 2, THERE SHOULD BE NO OTHER WRITINGS, JOTTINGS OR INSCRIPTIONS ON THE QUESTION PAPER EXCEPT THE MATRICULATION NUMBER OF THE STUDENT. QUESTION ONE. (@). Briefly define the blanking press toc!s work operation. Th). Study Fig Q1 (b) properly and determine the values of L mm and B mm respectivel; the following: (i). The blanking force N (ii). The work done Nm, for one complete completion ofthe ly. Estimate also blanking process. (ii). The percentage material utilisation. Take: t= 4mm,X=2.90mm and t=95N / mm? (@. Briefly define the bending press work operation. Scanned with CamScanner =o 24 il ea Sat & a 42 mt La i | Fig Qt (b). A BLANKING LAYOUT. QUESTION TWO.the clip bending of Fig Q 2 (b); if the die opens for eight times the material thickness, the circle of radius Rolin Is of three (3) coils at point whilst the ultimate tensile strength ofthe matetial ofthe lip is 400N/mm?, & 30° 6 a X% a D , “Vi a Se Bp Z Z Z = : E z 2 a s 2 2 4 2 Rg 8 ay 4 ; ¢ oe Fig Q2 (b). A BENDING PRESS ‘WORK OPERATION. QUESTION THREE, G), Briefly define the piercing press work operation. ©). The gasket of Fig Q.3(0) was tobe produced by plercing a cork material Of 6 mm thickness anda shear stress of 105N/ mé, Study the layout Properly and determine the following: (i). The material B Srecifcation required for producing the gasket. (i), The percentage material utilisation (li), The Plereing force, Fr. N:(iv) The Workdone ay the pumctrift! of the material material yuptured at 30% of the ickness & -—_+—_~¢ | a3 4 bea We ¥ Fig Q 3(b). A PIERCING PRESS TOOLS WORK OPERATION. Scanned with CamScanner, _ J *‘ QUESTION FOUR, (@)Enumerate any five (5) major factors that could actually influence your decision to replace an in - house production facility. (0). An in - house production facility was bought for N380, 000:00; eight (8) years ago, It has an estimated useful life span of twenty (20) years, an annual operating cost of N90, 000:00 and a salvage value of N15, 00:00. Presently, a new multipurpose production facility intended to boost production as well as the quality of the product wil cost ¥ 480,000:00, with an estimated useful life span of twenty five (25) years, an annual operating cost of ¥ 40, 000:00 and a salvage value of N20, 000:00. If, however, the rate of capital recovery is fifteen per cent (15 %) at an estimated life span of fifteen (15) years, advise Management on the purchase / replacement of the in ~ house production facility. QUESTION FIVE, @). Briefly explain the press work operation, extrusion and classify it accordingly. (b). The slug going through the extrusi process of Fig Q5 (b) has yield stress in pure shear given a: SON /mm* with an initial diameter of 63mm and a final diameter of 7mm. Estimate the actual extrusion Pressure of the process and the fractional reduction, sue Die SLUG CONTAINER |__exmunensstar—— J— DIE HOLDER, PRESSURE PAD ig. Q5 (b). DIRECT EXTRUSION METHOD, Scanned with CamScannerdustry: sh a tool rake angle of tinuous chip SkN and utting processes in th Jj on a lathe machine wi rm and the Tength of the com given as: six. ommenrontne general considerations for metal ct ess tube of jeter is turnet xd is. 30m/mil olution is 105mm. The hor ‘mt; determine the following os, QuEsTio" ©, yp a sear gon The cutting SPEC generated for one TeV 2.25KN respectively. IfAc= 35 x 10~* F 84mm outside diam n, depth of cut is 0.85m ital and vertical forces are 1. Vs, Ve, Weand Wr. eration. ‘pove, as prepared by one HND Ill PT ‘QUESTION SEVEN. jrawing press tools work oP is 21mm, (@). Briefly comment on the wire di (b). In the industrial wire drawing process of FigQ7 (b) at neering Student (Manufacturing Option): The initial diameter of the bar nt of fiction is 0.35, the included angle of the die is 40° (0. The drawing force. (i) The splitting force by the dies. Mechanical Engi whilst its final diameter is 3.5mm, the coefficie! ‘and the mean die pressure is 140kN /m?. Determine edie and (iif). The percentage reduction, between the two halves of th L Fig Q7 ig Q7 (b). A WIRE DRAWING PRESS WORK OPERATION. Scanned with CamScannerHINT: SOME VERY USEFUL FORMULATIONS pis. a) Fp = Froosa" + sina*(N), ty[ Eso eGo") (N/m) are fc e peso oF a0" 0°) (NID Mr (eater ary te nh ares Wr, | %100%, Fa= no?y (4) =f Bultim), Y= cle (m?), ne tom 4A) x 100% P= oavsasvin(4 Aerm y = V3. K (N/m), if von , Mises’ yield criterion is applied. Y = 2K (N /m?), if Tresca’s yield criterion is applied. Lr = SL, W=FX,P= (Ar As) (1+ cota). Quy (2 =P), ss an 25 = ay 4 n= Goyer aT ays l-« (3) tana” .s =e +) ea" + sina’) Ly =| 7 anor) w= SppmP, C= 15t B= 0.015H +t, E Fe +rPrt, inee-( Bee) Vs = 5 T= Resin a yee. ; u cosa’ _ yy cosa® 1 Vet (opin), Vs = Veg = veSEES (on/min) | | | 5 Scanned with CamScannerYABA COLLEGE OF TECHNOLOGY, YABA. LAGOS. ‘SCHOOL OF ENGINEERING. MECHANICAL ENGINEERING DEPARTMENT. SECOND SEMESTER: 2020 / 2021 ACADEMIC SESSION EXAMINATIONS, EM 423 — PRESS AND CUTTING TOOLS.. iG. ROM THE AVAILABLE SEVEN (7) QUESTIONS. INGS, JOTTINGS OR INSCRIPTIONS ON THE OF THE STUDENT. ME: 3 HOURS, ‘TITLE: MI Sounst cope (FT) MECHANICAL ENGINEERIN' a ‘ATTEMPT ANY Five (5) QUESTIONS FI z THERE SHOULD BE NO OTHER WAIT! + QUESTION PAPER EXCEPT THE MATRICULATION NUMBER QuESTION ONE. ‘ows the\blanking layout of a component for five (5) productions per batch as prepared rkshop \Attendant of Mechanical Engineering Workshop I! of the College. Using Fig Q1 g exercise. The ed the Fig at sh by the Wor calculate the blanking force and work done in the course of the blankin as given, its shear stress Is 85N / mm? and the punch penetrat ness of the material is 4mm, tl material for 2.45mm before rupture. Estimate also, the percentage material utilisation. Se Sa m Se an Pe ear a x L 4 2 (mm) 5 Fig Q1. BLANKING LAYOUT. QUESTION TWO. A 63mm diameter bar was machined on a lathe machine with a single point tool of rake angle 15°. The cutting speed is found to be 30m / minutes; Its depth of cut is 0.40mm while its length of a continuous chip for one revolution was 90mm. The cutting force is 5. 850 kN with a thrust of 2.850kN and given that the area of the chip is 20 x 10 ~ ° m*. Determine the following parameters of the machining process. Scanned with CamScanner» (a). The coefficient of friction of the machining process. M (b). The work done in overcoming friction. WF (©). The total work done during the machining process. “>F {d). The shear velocity, Ns (e}. Work done in shear, WS ‘QUESTION THREE. ‘The press tools piercing layout of the gasket of a gas turbine Is 28 shown in Fig 03. The material de from a cock material of 7mm thick, Its shear stress is SSN / mm’, Its of the gear box is ma idity is 125 MN / mm’, Study the given Fig Q3 density is 3500k8 / m?, whilst its modulus of rigi rnd determine the following: the material specification, the % material utilisation, the properly a piercing force, thickness ofthe material. The strip of the gasket is 18 mm wide. the work done if the material ruptures at a punch penetration of 30% of the Fig Q3. A PIERCING LAYOUT ‘QUESTION FOUR. (2). Briefly outline any of the five (5) factors that could actually influence your decision to replace an in-house press tool, (b). A dri ji ei Jig was bought for 8250, 00:00; eight (8) years ago. It has an estimated useful life of 25years, an annual operating cost of N85, 000:00 and a salvage value of 10, 000:00. 2 Scanned with CamScanneree YABA COLLEGE OF TECHNOLOG SCHOOL OF ENGINEERING. MENT: MECHANICAL ENGINEERING DEPAR’ COURSE CODE / TITLE: MEM 423 ~ PRESS AND XAMINATION. SECOND SEMESTER 2014 2015 ACADEMIC SESSION oor CLASS: HND II FT MECHANICAL ENGINEERIN\ TIME: ReCULATION NUMBER OF STUDENT «..- . UCTIONS gBSTIONS. . ATTEMP: UESTIONS FROM THE AVAILABLE SEVEN (7) Q! & 2 THER aD ae NO OTHER WRITINGS, JOTTINGS OR INSCRIPTIONS ON THE (QUESTION PAPER EXCEPT THE MATRICULATION NUMBER OF THE STUDENT: QUESTION ONE (@). Explain the term “PIERCING?” as used in most press tools operations. (). The gearbox gasket of Fig QI (b) is made from a synthetized cork material specified as: 400 x 200 x 3 mm, the strip ‘width is $0 mm and its yield shear stress is 85 N / mm’, Estimate the piercing force and work done in the course of producing it, if the gasket material ruptures at 30% of the thickness of the material. al Fig QI (b) GEARBOX GASKET QUESTION TWO (a). Explai (@). Explain the term “BEND ALLOWANCE” as used in the press tools industry. 1 die i x stress is350.N/ mm, pens eight times the thickness of the material, whist its ul te yield J imate yiel ___ _ Scanned with CamScannerFig Q2 (b) CLIP BENDING QUESTION THREE Briefly enumerate and explain any five tres. e factors that could actually influence your decision to replace a press tool of )..A press tool was bought for 200,000.00 five years ago, with an estimated useful life span of twenty years, an annual operating cost of 8,000.00 and a salvage value of 84 10,000.00. To boost the-volume-of proshiction andthe — acsctic values of the products, Management proposed the purchase of a challenger press tol. The cost of the challenger res tool is 8 300,000.00 with a life span of twenty five years, an annual operating-eost of N-5,000.00.and salvage ‘value of § 12,000.00. As the newly employed production engineer, advise Management accordingly if the rate of capital recovery is 12% QUESTION FOUR (). Briefly explain BLANKING. ©), Fig Q4 (6) is the blanking layout of an opener stock to be mass produced from mild stel plate of four millimetres thick, Given that the shear stress of the material is 75 N /mm?, whilst it ruptures at 35% of its thickness, estimate the following: (@. The material specification for production. (i. Percentage material utilisation. ‘The required blanking force, Gil). The work done in blanking a batch size of five pieces per production, Scanned with CamScanner