Engineering - Exam Papers - HL - Paper - 2001

300 Marks
Answer Question 1, Sections A and B and FOUR other questions.

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1.
(100 Marks)
Section A - 50 Marks
Give brief answers to any ten of the following :
(a) What safety precautions should be observed when using cutting fluids ?
(b) Describe the flotation separation method shown below.
(c) Identify in which cubic crystal form shown at (i) and (ii) is slippage more likely to occur and state why this is the case.
(d) Identify and outline the function of either the transformer or rectifier shown in the circuit diagram.
(e) Name any three essential differences between metals and non-metals.
(f) Identify the main processes used to manufacture any one of the items shown.
(g) Explain the term elastic memory with reference to thermoplastics.
(h) Name any three of the electronic symbols shown and briefly outline their function.
(i) Explain the term creep with reference to metals.
(j) What environmental factors hasten the corrosion rate of metals ?
(k) Briefly describe any two common defects in metal crystals.
(l) Outline the advantages of compresses air over other forms of power supply.
(m) What contribution did any one of the following make to technology ?
(i) Gottlieb Daimler;  
(ii) Daniel Bernoulli; 
(iii) Robert Boyle.
Section B - 50 Marks
Answer all of the following :
(n) (i) Outline the principle of carburation using the sketch below.
(ii) Describe two main functions of the carburettor.
(o) (i) Explain the difference between Down Draught and Side Draught carburettors.
(ii) Describe one design consideration governing the use of a side Draught carburettor.
(p) What is meant by the term mixture strength and why is it necessary to provide a variety of strengths.
(q) Describe the operation and function of the float chamber in the diagram given below.
(r) Utilising the given diagram describe the purpose of any three of the following.
(i) Throttle lever;
(ii) Throttle butterfly;
(iii) The choke control level;
(iv) Venturi;
(v) Emulsifying tube;
(vi) Idling adjustment screw.
2.
(50 Marks)
(a) The force-extension graphs for three non-ferrous metals are shown.  Redraw the graphs into your answer book matching the metals listed below with a corresponding graph and briefly outline the ductility of each.
(i) Soft Copper;
(ii) Aluminium;
(iii) Soft Brass.
(b) Answer each of the following.
(i) Define any two of the following.
Malleability;  Toughness;  Hardness;  Young's Modulus of Elasticity.
(ii) Suggest a suitable inspection technique for detecting the following defects.
Internal cavities in aluminium castings;  Surface cracks in cast iron plates;  Internal flaws in welding joints.
(c) A non-destructive test is represented diagrammatically in the drawing below.
(i) Name the test;
(ii) Outline the principles of operation;
(iii) Suggest a suitable application.
3.
(50 Marks)
(a) Redraw the given iron-carbon diagram into your answer book and label the following phases.
(i) Ferrite;
(ii) Ferrite and Austenite;
(iii) Ferrite and Pearlite;
(iv) Austenite;
(v) Austenite and Cementite;
(vi) Cementite and Pearlite.
(b) (i) Define any two of the following terms.
Ferrite;  Pearlite;  Cementite.
(ii) Explain the effects on a 0.7% carbon steel when quenched rapidly from 900°C and cooled slowly from 900°C.
(c) Explain the operation of the thermoelectric pyrometer shown below.
4.
(50 Marks)
(a) Select any two of the following terms and give a definition for each selected.
(i) Eutectoid point;
(ii) Dendrite growth;
(iii) Vacancy;
(iv) Solid Solution.
(b) Redraw the Cadmium - Zinc equilibrium diagram, given below, into your answer book and identify and explain each of the following terms.
(i) Liquidus;
(ii) Solidus;
(iii) Eutectic point.
(c) Using the above diagram explain the solidification process from 400°C for an alloy with 30% cadmium.
5.
(50 Marks)
(a) Answer any two of the following.
(i) What is meant by dissolved acetylene ?
(ii) Describe the three types of flame shown at (A), (B) and (C).
(iii) Outline an application for each flame.
(b) Explain why it is necessary to protect the weld area from atmospheric contact
(c) Describe, with the aid of a diagram, the main features, operation and application of one of the following welding processes.
(i) Metal inert gas welding;
(ii) Tungsten inert gas welding.
OR
(c) Explain the following terms in relation to robotic control welding.
(i) Lead through method of programming;
(ii) Working envelope;
(iii) Machine vision.
6.
(50 Marks)
(a) Explain the type of polymerisation which occurs in the production of each of the following.
(i) Bakelite;
(ii) Polyvinylchloride;
(iii) Polyethylene.
(b) Describe the main differences between thermoplastics and thermosets under the following guidelines.
(i) Chemical bonding;
(ii) Properties;
(iii) Internal Structures.
(c) Describe, using the following guidelines, the process of extrusion shown below.
(i) Equipment used;
(ii) Process;
(iii) A typical end product.
7.
(50 Marks)
(a) Identify any three of the following.
(i) Identify the forces A and B acting on he cutting tool shown.
(ii) Distinguish between Orthogonal and Oblique cutting forces.
(iii) Describe an instrument for measuring cutting forces.
(iv) Suggest how altering the rake angle would affect the shear plane angle.
(b) Answer any two of the following.
(i) Distinguish between the two chucks shown and describe their applications.
(ii) Name and outline the principles of operation of the grinding process shown.
(iii) Describe the principles of operation of the quick - return mechanism shown.
(c) With reference to metrology, explain any four of the following terms.
(i) Optical Projector;
(ii) Sine Bar;
(iii) Slip Gauges;
(iv) Precision Balls;
(v) Comparator.
OR
(c) With reference to CNC lathework, indicate the code used for any four of the following functions.
(i) Tool change;
(ii) Absolute dimensions;
(iii) Spindle start / reverse;
(iv) Continuation code;
(v) Linear interpolation.
8.
(50 Marks)
(a) Identify any one of the devices shown below and explain how it functions.
(i)
(ii)
(b) Answer any two of the following.
(i) State the advantages of helical toothed gears over straight toothed gears as shown.
(ii) Describe one application of a rack and pinion mechanism.
(iii) Name the gear train shown and describe the purpose of the idler gear and outline the relationship between driver and driven gear.
(c) Identify the electronic components labeled A, B, C, D, and outline an application for the circuit.
OR
(c) Describe the operation of an automatic cross slide or an automatic carriage on a centre lathe.