(c) Elaborate the principles of vacuum forming process for thermoplastics, given a shaped form. Question 5 (a) [4] i. Explain the Spin welding process with the help of a diagram. [6] ii. Name the two requirements for the process to be successful? [4] (b) i. Which are the most common fastners used in assembly? [2] ii. Which joining process could be suitable for joining rubber sheet material? [2] (a) i. Give three reasons why mechanical fastners must be kept to a minimum for the assembly process. [3] i. What are the three things recommended to lower the assembly costs? [3]

(a) With the aid a diagram, describe the principle of spot-welding process.

Why is cost a consideration in joint design?

What are the advantages and disadvantages of welding as compared to other types of assembly operations?

a) A bicycle frame is being designed to carry a pedal force of 800N. Assuming axial loading only, which material will produce the lightest frame out of the two in the table below? Assume a design factor of 1.2  b) If the bicycle frame is being welded together and an internal flaw size of 30mm results, which material will produce the lighter section? (Apply a design factor of 1.2 If the bicycle frame needs to last a minimum 3 x 105 cycles, with an average stress of 150MPa and an alternating stress of 200MPa, use the Soderberg criterion to pick a suitable material from the two alloys listed above. Show all your working.

(b) You are required to joint two parts together by joining process. One of the parts needs to be remove out of an assembly and replaced with a new part several times during the product's life due to failure. Recommend a suitable ioining process for this condition with ONE (1) example.

(4) The average flow stress is the flow stress multiplied by which of the following factors: (a) n, (b) (1-n), (c) 1/n, or (d) 1/(1+n), where n is the strain hardening exponent? (5) The strength of a brazed joint is typically (a) equal to, (b) stronger than, or (c) weaker than soldered joint? (6) Thread cutting operation is normally performed on which one of the following machine tools: (a) drill press, (b) lathe, (c) milling machine, (d) planer, or (e shaper? (7) Of the following cutting conditions, which one has the greatest effect on cutting temperature: (a) cutting speed, (b) depth of cut, or (c) feed? (8) The maximum possible draft in a rolling operation depends on which of the following parameters (two correct answers): (a) coefficient of friction, (b) roll diameter, (c) roll velocity, (d) stock thickness, (e) strain

What do you understand by the term welded joint? How it differs from riveted joint?

Are the Expansion joints, used to mitigate thermal stress in materials?

A pipe can be manufactured as (a) seamless (cold rolled and extruded) or (b) hot rolled and welded.  (i) Describe the process for manufacturing each type of pipe:  (a) Seamless (cold rolled and extruded) pipe;  (b) Hot rolled and welded pipe.  (ii) Why might a cold rolled seamless pipe be better suited to drilling operations than a hot rolled and welded pipe? A particle reinforced composite (containing flakes) has particles evenly distributed throughout the matrix where the rule of mixtures applies.  (i) State THREE effects that a larger volume of carbon particles within the matrix produces. A drill bit is a cutting tool on the end of a rotary subsea drill. A Thermally Stable Polycrystalline (TSP) drill bit can be used to drill a subsea well. TSP bits are man-made polycrystalline structures consisting of a multitude of synthetic diamond crystals sintered together at high pressure and temperature, used to aid cutting into hard rock formations.  (i) Describe THREE reasons why this type…