UNIVERSITY OF PRETORIA UNIVERSITEIT VAN PRETORIA Department of Mechanical and Aeronautical Engineering Departement Meganiese en Lugvaartkundige Ingenieurswese Copyright reserved Kopiereg voorbehou Graphical Communication MGC 110 Grafiese Kommunikasie MGC 110 Semester test 2 Time: 120 minutes 15 April 2011 Marks: 100 Semester toets 2 Tyd: 120 minute 15 April 2011 Punte: 100 Lecturers: Course Coordinator: Co-Lecturers: Mr J.J. Pienaar Mr G.D. Booysen Mr R.F. Meeser Dosente: Kursus Koordineeder: Mede-Dosente Mnr J.J. Pienaar Mnr G.D. Booysen Mnr R.F. Meeser Instructions: Answer all questions. The drawing and the multiple choice marksheet must both be handed in separately. Instruksies: Beantwoord alle vrae. Die tekening en die meervuldige keuse merkleesblad moet afsonderlik ingehandig word. QUESTION 1: Manufacturing theory [30] VRAAG 1: Vervaardigings-Teorie [30] TO BE COMPLETED ON THE MULTIPLE CHOICE CHART SIDE 1 VOLTOOI HIERDIE VRAE OP DIE MULTI KEUSE KAART KANT 1 FOLLOW THE INSTRUCTIONS ON THE CHART DO NOT MAKE ANY MARK ON THE CHART OUTSIDE THE CIRCLES PROVIDED. VOLG DIE INSTRUKSIES OP DIE KAART. MOET NIE OP ENIGE ANDER PLEK AS DIE SIRKEL OP DIE KAART ENIGE MERKE MAAK NIE. You may not mark the answers on your questions paper. Use the space provided on page 7 for your calculations U mag nie die antwoorde op u vraestel merk nie. Gebruik die deel op bladsy 7 vir rofwerk. 1
1.1) Which one of the following casting metals is most important commercially? A. Cast Iron. B. Aluminum and its alloys. C. Bronze. D. Cast Steel. E. Zinc alloys. 1.1) Watter een van die volgende giet metale is kommersieël die belanrikste? A. Giet Yster. B. Aluminium. C. Brons. D. Giet Staal. E. Sink legerings. 1.2) Identify the die in Figure 1of a blanking press. 1.2) Identifiseer die matrys in Figuur 1 van die ponspers. 1.3) Which one of the following High Energy Rate Forming processes is most widely used. Figure 1 1.3) Watter een van die volgende Hoë Energie Tempo Prosesse word die meeste gebruik. A. Electromagnetic Forming. B. Electro hydraulic Forming. C. Electrostatic Forming. D. Electron Beam Forming. E. Explosive Forming. A. Elektromagnetiese Vorming. B. Elektrohidrouliese Vorming. C. Elektrostatiese Vorming. D. Elektron Straal Vorming. E. Ontploffings Vorming. 2
1.4) A horizontal true centrifugal casting process is used to make lead pipe for chemical plants. The pipe has a length of 500mm, outside diameter of 70mm and a wall thickness of 6mm. The density of lead is 11300 kg/m 3 determine the rotational speed that will provide a G-factor of 60. A. 1238 rpm B. 3890 rpm C. 1751 rpm D. 1380 rpm E. 749 rpm 1.4) Ware horisontale sentrifugale giet word gebruik om lood pype vir chemiese aanlegte te vervaardig. Die pype is 500mm lank, buite diameter 70mm en wand dikte 6mm. Die digtheid van lood is 11300 kg/m 3 bepaal die rotasie spoed wat n G-faktor van 60 sal gee. A. 1238 rpm B. 3890 rpm C. 1751 rpm D. 1380 rpm E. 749 rpm 1.5) Strip mild steel stock 3mm thick and 50mm wide with a shear strength of 350 MPa must be parted as shown in Figure 2. Determine the force necessary for this parting operation? A. 152 kn B. 114 kn C. 127 kn D. 144 kn E. 134 kn 1.5) Strook sagte staal 3mm dik en 50 mm breed met n skuif sterkte van 350 MPa moet verdeel word soos aangetoon in Figuur 2 bepaal die ponskrag wat benodig word om die strook te verdeel. A. 152 kn B. 114 kn C. 127 kn D. 144 kn E. 134 kn Figure 2 3
1.6) The foreman of the workshop needs to know from you how long he must cut the plate before bending it to produce the part as shown in Figure 3. A. 158.8mm B. 163.3mm C. 164.6mm D. 169.2mm E. 173.5mm 1.6) Die voorman van die werkswinkel wil by jou weet hoe lank hy die plaat moet afsny voordat hy dit buig om die onderdeel soos aangetoon in Figuur 3 te produseer. A. 158.8mm B. 163.3mm C. 164.6mm D. 169.2mm E. 173.5mm Figure 3 1.7) He also wants to know the bending force required for this operation to set his machine? He will bend it with a V-die opening of 30mm. The tensile strength of the material is 400 MPa. A. 110.8 kn B. 254.7 kn C. 156.3 kn D. 442.2 kn E. 332.5 kn 1.7) Hy wil ook weet wat die buig krag moet wees sodat hy sy masjien kan instel vir die buigbewerking. Hy sal dit buig met n V- matrys met n opening van 30mm. Die treksterkte van die material is 400 MPa. A. 110.8 kn B. 254.7 kn C. 156.3 kn D. 442.2 kn E. 332.5 kn 4
1.8) You as a junior engineer must design a punch to blank round disks for a drawing operation to produce a cup as shown in Figure 4. Determine the diameter of the punch ignoring punch radius and wall thinning in the drawing operation. A. 195mm B. 205mm C. 210mm D. 215mm E. 200mm 1.8) As n junior ingenieur word jy gevra om n pons te ontwerp om ronde skywe te pons vir n diep trek bewerking om die koppie, soos aangetoon in Figuur 4, te produseer. Bepaal die diameter van die pons wat jy benodig en ignoreer die ponsradius en verdunning van die kante in die dieptrek proses? A. 195mm B. 205mm C. 210mm D. 215mm E. 200mm Figure 4 1.9) For the tube shown in Figure 5, the wall thickness is 5 mm and it has an inner diameter of 60mm and a length of 50mm. Determine the final length of this tube if it is to be spun to a wall thickness of 3mm. A. 63mm B. 72mm C. 86mm D. 93mm E. 97mm 1.9) Die buis in Figuur 5 se wand dikte is 5mm en het n binne diameter van 60mm en is 50mm lank. Die wand dikte moet na 3mm gespin word. Bepaal die finale lengte van die buis. A. 63mm B. 72mm C. 86mm D. 93mm E. 97mm 5
Figure 5 SPACE FOR YOUR CALCULATIONS; IT WILL NOT BE GRADED SPASIE VIR BEREKENINGE; DIT SAL NIE NAGESIEN WORD NIE 6
SPACE FOR YOUR CALCULATIONS; IT WILL NOT BE GRADED SPASIE VIR BEREKENINGE; DIT SAL NIE NAGESIEN WORD NIE g= 9.81 m/s 2 mv F = R 2 30 2gGF N = π D F=StL Formulas /Formules 2 K bf TSwt F = D K = 1.33 for V-Bending and K = 0. 33 for edge bending bf A BA = 2π ( R + K bat), 360 K = 0.5 for R 2t and K = 0. 33 for R < 2t ba ba bf 7
QUESTION 2: Orthographic drawing [70] TO BE COMPLETED ON THE FRONT OF YOUR A3 DRAWING SHEET A cast component is shown in figure 6. Draw the following views to fully describe the component. A full section principle view. 2 Auxiliary views that fully describe the details of the two inclined surfaces on the right of the component. Both slots on surface A must be visible. A partial top view. VRAAG 2: Ortografiese tekening [70] VOLTOOI OP DIE VOORKANT VAN U A3 TEKENVEL n Gietstuk word aangetoon in Figuur 6. Teken die volgende aansigte om die component volledig te kan beskryf. n Volsnit vooraansig. 2 hulp aansigte om die skuins vlakke op die regterkant van die komponent volledig te beskryf. Beide gleuwe moet sigbaar wees. n Gedeeltelike bo-aansig. Indicate all dimensions and relevant hidden detail. Use third angle projection for this question. Use the following title: CAST Use the following drawing number: GX-T2 X indicates your specific group number. Dui alle mates en toepaslike verborge detail aan. Maak gebruik van derde hoekse projeksie vir hierdie vraag. Gebruik die volgende title: GIETSTUK Gebruik die volgende tekening nommer: GX-T2 X dui u spesifieke groepnommer aan. 8
Figure 6/ Figuur 6 9