INDIAN INSTITUTE OF TECHNOLOGY MADRAS Department of Mechanical Engineering ME3302 Automation in Manufacturing Assignment 2 Due Date: Friday, March 26, 2021 1. Solve the following problems: a) A digital flow meter operates by emitting a pulse for each unit volume of fluid flowing through it. The particular flow meter of interest here has a unit volume of 57.9 cm3 per pulse. In a certain process control application, the flow meter emitted 6489 pulses during a period of 3.6 min. Determine (a) the total volume of fluid that flowed through the meter and (b) the flow rate of fluid flow. (c) What is the pulse frequency (Hz) corresponding to a flow rate of 75,000 cm3 /min? b) The shaft of a stepper motor is directly connected to a lead screw that drives a worktable in an x-y positioning system. The motor has a step angle = 5. The pitch of the lead screw is 6 mm, which means that the worktable moves in the direction of the lead screw axis by a distance of 6 mm for each complete revolution of the screw. It is desired to move the worktable a distance of 300 mm at a top speed of 40 mm/sec. Determine (a) the number of pulses and (b) the pulse frequency required to achieve this movement. c) A voltage signal with a range of zero to 115 V. is to be converted by means of an ADC. Determine the minimum number of bits required to obtain a quantization error of (a) 5 V maximum, (b) 1 V maximum, (c) 0.1 V maximum. d) A turning operation is to be performed on an NC lathe. Cutting speed = 2.5 m/s, feed = 0.2 mm/rev, and depth = 4.0 mm. Workpiece diameter = 100 mm and its length = 400 mm. Determine (a) rotational speed of the work bar, (b) feed rate, (c) metal removal rate, and (d) time to travel from one end of the part to the other. e) The worktable of an NC machine is driven by a closed-loop positioning system which consists of a servomotor, leadscrew, and optical encoder. The lead screw pitch = 4 mm and is coupled directly to the motor shaft (gear ratio = 1:1). The optical encoder generates 225 pulses per leadscrew revolution. The table has been programmed to move a distance of 200 mm at a feed rate = 450 mm/min. (a) How many pulses are received by the control system to verify that the table has moved the programmed distance? What are (b) the pulse rate and (c) motor speed that correspond to the specified feed rate? 2. The part in Figure 1 is to be drilled on a turret-type drill press. The part is 15.0 mm thick. There are three drill sizes to be used: 8 mm, 10 mm, and 12 mm. These drills are to be specified in the part program by tool turret positions T01, T02, and T03. All tooling is high speed steel. Cutting speed = 75 mm/min and feed = 0.08 mm/rev. Use the lower left corner of the part as the origin in the x-y axis system. Write the part program in the word address format using absolute positioning. Fig 1. Part Programing 3. Write the APT geometry statements to define the outline of the cam shown in Figure 2. Fig 2. APT Programing ******************************************
