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Cork Institute of Technology
Higher Certificate in Engineering in Biomedical Engineering – Award
(NFQ – Level 6)
Summer 2007
Materials and Manufacturing Processes – Paper 2
(Time: 3 Hours)
Instructions Answer TWO questions from section A and ONE question from Section. B Use separate answer books for each Section.
Examiners: Mr. D. Sullivan Mr. N. Morris Mr. M. Murphy Mr. P. McHugh
Section A - Answer TWO Questions
Q1. (a) Sketch and describe the operation of Retro-Reflective scanning. (8 Marks)
(b) Sketch and describe an Inductive sensor. (6 Marks) (c) Sketch and describe Diffuse scanning and state its main purpose. (6 marks)
Q2. (a) List the sequence of operations for the electro-pneumatic sequence shown in Fig2. (8 Marks) (b) Divide the sequence into groups, stating how many groups there are. (6 marks) (c) Prepare a Boolean expression for the following Logic symbol.
(6 Marks)
Q3. (a) Sketch a PLC ladder diagram to produce the following sequence
A+B+C+C-B-A- (10 marks) (b) Draw a Ladder program to illustrate the use of a counter as found within a P.L.C. (10 marks)
S
S2 K
Section B - Answer ONE question (25 marks)
Q4. (a) Differentiate between grinding honing and lapping with respect to the form taken by the abrasive used. (3 marks)
(b) Illustrate, with the aid of diagrams, the structure of a grindwheel and show how the wheel is self sharpening. (8 marks)
(c) Before mounting on a spindle, a grindwheel must be checked for soundness. Explain how this is done. (6 marks)
(d) Explain the function of the bond with reference to grinding. Name 4 types of bond and state when each might be used. (8 marks)
Q5. (a) Give an example of a simple closed loop control system and explain how it works. (5 marks) (b) According to basic convention, how are the three principle axes on a machine tool designated? (5 marks) (c) The following information relates to a cutting test under orthogonal conditions: Rake Angle = 12° Chip Thickness ratio = 0. Axial force Fa = 880 N Tangential force Ft = 1250 N
Calculate the shear plane angle. Use Merchants Circle to determine the shear force Fs , the friction force F f, the compression force Fcm and the normal force N in the above operation. Calculate the co-efficient of friction at the chip/tool interface. Note: Merchants circle must be drawn on the graph paper supplied. (15 marks)
