UNIVERSITY OF PRETORIA
UNIVERSITEIT VAN PRETORIA
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Department of Mechanical and Aeronautical Engineering
Departement Meganiese en Lugvaartkundige Ingenieurswese
Graphical Communication MGC 110
Grafiese Kommunikasie MGC 110
Examination paper
4 June 2012
Internal Examiners
Lecturers:
Time: 180 minutes
Marks: 100
Eksamen vraestel
4 Junie 2012
Tyd: 180 minute
Punte: 100
Mr R.F. Meeser
Ms L Smith
Interne Eksamineerders
Dosente
Mnr R.F. Meeser
Me L Smith
Eksternal Examiner
Dr Lee Kim Seng (National University of
Singapore)
Eksterne Eksamineerder
Dr Lee Kim Seng (National University of
Singapore)
Instructions:
 Answer all questions
 The question paper and the multiple choice
mark sheet must both be handed in
seperately
Instruksies:
 Beantwoord alle vrae
 Die antwoordblad 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 6 for your calculations
U mag nie die antwoorde op u vraestel merk nie.
Gebruik die deel op bladsy 6 vir rofwerk.
NB FORMULAS ON PAGE 10
NB FORMULES OP BLADSY 10
1
1.1) Which one of the following is not a
machining operation?
(2)
A. Drilling
B. Broaching
C. Grinding
D. Drawing
E. High energy beam machining
1.2) The most widely used casting process is
(2)
A. Sand Casting
B. Die Casting
C. Lost Wax Casting
D. Slush Casting
E. Expanded Polystyrene Process
1.1) Watter een van die volgende is nie ‘n
masjineerings operasie nie?
(2)
A. Boorwerk
B. Trekvrees
C. Slyping
D. Uittrekking
E. Hoë-energie straal masjineering
1.2) Die giet proses wat die meeste gebruik word
is
(2)
A. Sandgiet
B. Matrysgiet
C. Verlore Was giet
D. Spoel giet
E. Polystyrene proses
Figure1.1/Figuur1.1
1.3) You are working at a sheet metal factory,
and you have been tasked to do the design of a
dustbin as depicted in Figure 1.1. Calculate the
staring BLANK size for this dustbin to be used
in a drawing operation. You may ignore bend
radii.
(4)
A. 0.486m
B. 0.7m
C. 0.528m
D. 0.443m
E. 0.379m
1.3) U werk by ‘n plaatmetaal fabriek, u was die
taak gegee om ‘n asblik soos in Figuur 1.1 te
ontwerp. Bereken die begin grootte van die
BLANK vir die asblik om gebruik te word in ‘n diep
trek proses. U mag die buig radiusse ignoreer. (4)
A. 0.486m
B. 0.7m
C. 0.528m
D. 0.443m
E. 0.379m
2
1.4) Would this drawing operation be feasible in
one single drawing step?
(2)
A. Yes
B. No
A. Ja
B. Nee
1.5) Calculate the force required to at once
punch out one handle hole on the dustbin in
Figure 1.1 if the effect of the 200mm diameter
curvature is not taken into account, and the
material used has a shear strength of 400Mpa.
(4)
1.5) Bereken die ponskrag wat benodig word om
een handvatsel gat van die asblik in Figuur 1.1
gelykmatig uit te pons indien die effek van die
200mm diameter ronding nie in ag geneem word
nie, en die materiaal ‘n skuifsterkte het van
400Mpa.
(4)
A. 126KN
B. 251KN
C. 98KN
D. 318KN
E. 223KN
A. 126KN
B. 251KN
C. 98KN
D. 318KN
E. 223KN
1.6) A true centrifugal casting operation is to be
performed in a horizontal configuration to make
cast iron pipe sections. The sections will have a
length of 3m, outside diameter of 1m and a
thickness of 20 mm. Determine the G-factor for
a rotational speed of 300 RPM.
(3)
1.6) ‘n Ware sentrifugale giet moet in die
horisontale konfigurasie geskiet om giet yster
pype te vervaardig met die volgende dimensies
lengte 3m, buite diameter 1m en wand dikte
20mm. Bepaal die G-faktor vir ‘n rotasiespoed van
300 OPM.
(3)
A. 40
B. 80
C. 70
D. 60
E. 50
A. 40
B. 80
C. 70
D. 60
E. 50
1.7) Which one of the
disadvantage of die-casting?
1.4) Sou die operasie prakties uitvoerbaar wees
vir ‘n enkele trek aksie?
(2)
following
A. Shape restriction
B. High production rate
C. Quick cooling time
D. Thin components can be cast
E. Surface finish
is
a
(2)
1.7) Watter een van die volgende is n nadeel van
die matrys giet proses?
(2)
A. Vorm beperking
B. Hoë produksietempo
C. Vinnige afkoeling
D. Dun dele kan gegiet word
E. Oppervlakte afwerking
3
1.8) A sheet metal plate 50 mm wide is to be
bent as shown. Determine the starting length of
the sheet metal plate before bending
(3)
A. 81.96 mm
B. 84.96mm
C. 86.56mm
D. 88.92 mm
E. 87.23 mm
1.8) ‘n Plaat 50 mm breed moet gebuig word soos
aangetoon. Bereken die aanvanklike lengte van
die plaat voordat dit gebuig word.
(3)
A. 81.96 mm
B. 84.96 mm
C. 86.56 mm
D. 88.92 mm
E. 87.23 mm
Figure2/Figuur2
4
1.9) A round bar is to be machined to yield the
part in Figure 2. The part’s diameter is reduced
in a lathe after which a flat portion is cut on a
milling machine. Given a cutting speed of
80m/min, calculate the feed required to perform
the cut from a diameter of 40mm to 30mm in a
time of 1 minute with a single pass. (4)
A. 0.1mm/rev
B. 0.094mm/rev
C. 0.078mm/rev
D. 0.113mm/rev
E. 0.106mm/rev
1.9) ‘n Ronde staaf moet gemasjineer word soos
in Figuur 2 getoon. Eerstens word die staaf se
diameter verklein op ‘n draaibank en dan word die
plat stukkie afgefrees op ‘n freesmasjien. Vir ‘n
snyspoed van 80m/min, bereken die benodigde
voer om die staaf se diameter van 40mm na
30mm te verklein in ‘n enkel lopie in een minuut.
(4)
A. 0.1mm/rev
B. 0.094mm/rev
C. 0.078mm/rev
D. 0.113mm/rev
E. 0.106mm/rev
1.10) A face milling operation is used to
machine the top off of the cylinder with the
cutter as is given in Figure 2. Calculate the time
it will take for the cut to be completed given the
following:
(4)
1.10) ‘n Vlak frees bewerking word gebruik om die
bokant van ‘n silinder af te frees met ‘n snybeitel
soos aangedui in Figuur 2. Bereken die tyd
benodig om die operasie uit te voer met die
volgende gegee:
(4)
Chip load = 0.1mm/tooth
Rotational speed of cutter = 500 RPM
Spaander las = 0.1mm/tand
Rotasiespoed = 500 OPM
A. 3.8 s
B. 12.0 s
C. 5.3 s
D. 21.3 s
E. 9.2 s
A. 3.8 s
B. 12.0 s
C. 5.3 s
D. 21.3 s
E. 9.2 s
5
SPACE FOR CALCULATIONS. THIS WILL
NOT BE GRADED.
SPASIE VIR ROF WERK. DIT SAL NIE GEMERK
WORD NIE.
6
QUESTION 2: Assembly drawing
[50]
TO BE COMPLETED ON THE FRONT OF
YOUR A3 DRAWING SHEET
VRAAG 2: Samestellings tekening
[50]
VOLTOOI OP DIE VOORKANT VAN U A3
TEKENVEL
The detail drawings of a number of components
are shown in Figure 2.2. The components form
part of a ROOF HOIST POINT. There are
standard components used in the assembly
which are not shown in Figure 2.2.
Die detail tekeninge van ‘n aantal komponente
word getoon in Figuur 2.2. Die komponente vorm
deel van ‘n DAK HYS PUNT. Daar is standaard
komponente wat nie aangedui word op Figuur 2.2
nie.
Draw the following views to fully describe the
assembly.
Teken die volgende aansigte om die samestelling
te beskryf.



A FULL SECTION-principle view as is
seen from direction A in the schematic
diagram Figure 2.1.
An EXTERNAL right view as seen from
direction B.
A PARTIAL TOP view to show only the
mounting holes



‘n VOLSNIT-Vooraansig soos gesien uit
rigting A op die skematiese diagram Figuur
2.1.
‘n BUITE Regter-aansig soos gesien vanuit
rigting B.
‘n GEDEELDLIKE BO-aansig om slegs die
monteeringsgate te toon
Complete the item list for the assembly and add
the relevant dimensions.
Voltooi die item lys vir die sametelling en voeg die
nodige dimensies by.
Use third angle projection for this question.
Maak gebruik van derde hoekse projeksie.
Use the following title: “ROOF HOIST POINT”
Use the following drawing number: GX-EXAM
X indicates your specific group number.
G1 Tuesday 07:30
G2 Tuesday 10:30
G3 Wednesday 14:30
G4 Thursday 08:30
Gebruik die volgende titel:“DAK HYS PUNT”
Gebruik die tekening nommer: GX-EKSAMEN
X dui u spesifieke groepnommer aan.
G1 Dinsdag 07:30
G2 Dinsdag 10:30
G3 Woensdag 14:30
G4 Donderdag 08:30
Figure 2.1/Figuur 2.1
7
8
Question 3: Isometric drawing
[20]
Vraag 3: Isometriese tekening
[20]
TO BE COMPLETED ON THE BACK OF
YOUR A3 DRAWING SHEET
VOLTOOI OP DIE AGTERKANT VAN U A3
TEKENVEL
3 Views of a component is shown in Figure 3.
3 Aansigte van ‘n component word aangetoon
in Figuur 3.
Draw an isometric sketch of the component.
Teken ‘n isometriese skets van die
component.
Figure 3/ Figuur 3
9
FORMULA SHEET / FORMULE BLAD
CENTRIFUGAL CASTING / SENTRIFUGALE GIET
OTHER
=
=
ℎ
=
=
CUTTING / SNY
c = at
F = StL
BENDING / BUIG
=2
( +
)
<2 ,
= 0.33
≥2 ,
= 0.5
TURNING / DRAAIWERK
=
=
=
=
DRILLING / BOORWERK
=
=
=
=
MILLING / FREES
=
=
=
=
10