Assigment Manufacturing Process

FACULTI OF MECHANICAL ENGINEERING UNIVERSITI MALAYSIA PAHANG BMM3643 (Sem II 2012/13) Assignment 4 1. a) What distinguishes machining from other manufacturing processes? b) What is a machining center? c) How important is the control of interruptting-fluid temperature in trading operations performed in machining centers? Explain. (8 marks) 2. a) What are the primary considerations in tool selection? b) What is the service of a helical-tooth cutter over a straighttooth cutter for slab mill? c) What are the consequences if a cutting tool chips? (8 marks) 3. ) Why might it be coveted to use a heavy depth of cut and a lightheaded feed at a given fixture in number? b) Explain the reasoning behind the various design guidelines for turning. c) In drilling, the deeper the hole, the great the torque. Why? (8 marks) 4. a) For producing flat surfaces in mass production machining,how does face mill differ basically from peripheral milling? b) Why is end milling such an important versatil e process? c) Why is grain put important in grinding cycle per seconds? Explain the relationship between gumption size and surface finish. (8 marks) 5. ) Why has the wire-EDM process become so wide used in industry, especially in tool and die manufacturing? Explain. e) What is meant by the term overcut in electric discharge machining? f) What is the nature of the surface obtained by electro discharge machining? (8 marks) 6. g) Estimate the time required for face milling an 20. 32 cm-long, 7. 62 cm-wide brass block using a 2032 cm-diameter cutter with 12 HSS teeth. (Given Using the high-speed-steel tool, lets take a recommended cutting speed for brass (a copper alloy) at 90 m/min = 1. 5 m/sand the maximum feed per tooth as 0. mm) h) In a surface grinding operation performed on hardened plain carbon paper steel, the grinding wheel has a diameter = 200 mm and breadth = 25 mm. The wheel rotates at 2400 rev/min, with a depth of cut (infeed) = 0. 05 mm/pass and a crossfeed = 3. 50 mm. The reciprocating speed of the work is 6 m/min, and the operation is performed dry. Determine i) the length of contact between the wheel and the work, ii) the volume rate of metal removed. iii) If there are 64 agile grits/cm2 of wheel surface, estimate the number of chips formed per unit time. (10 marks)