Assignment #5 Material and Manufacturing Processes (M2794.001800) Fall 2014, Prof. Ahn, Sung-Hoon Out: November 13, 2014 / Due: 6PM, November 20, 2014 (Bldg. 301, Room 1405) 1. Figure 1 is an aluminum work-piece after flat milling. Diameter of the tool was 1.0 mm, feed per tooth was 0.25 μm. Find the spindle speed [rpm], and cutting speed [m/s]. Feed rate (linear speed) is 15 mm/min, and the number of cutter blades is 4. Figure 1. Work-piece after flat milling 2. Using the Taylor equation for tool wear and letting n = 0.3, calculate the percentage increase in tool life if the cutting speed is reduced by (a) 30% and (b) 60%. 3. In a surface-grinding operation, calculate the chip dimensions for the following process variables: D = 20 cm, d = 0.025 mm, v = 9.1 m/min, V = 1500 m/min, C = 77.5 per cm2, and r = 20. 4. Cast iron work pieces are machined by milling operation and grinding, respectively, as shown in the Figure 2. The geometry of the milling cutter and grinder, and process parameters, which are depth of cut (d), width of cut (w) and work piece speed (v), are shown in the Table 1. Answer the questions below. Tool V d w D Workpiece Fc v Figure 2. Schematic of cutting process 1 Table 1. Specifications of each process Cutting speed Specific Depth of cut Width of cut Tool diameter Work piece Process (V) energy (u) (d) (w) (D) speed (v) (m/min) (W-s/mm3) (mm) (mm) (m) (m/min) Milling 500 3 20 10 0.1 0.6 Grinding 2500 15 2 A. From the Table 1, calculate material removal rate of each process. B. Calculate the cutting force ( Fc ) acting on the milling cutter and grinder respectively. (Assume that the power consumed in the process and the torque required can be calculated with following equations: J mm3 W s rad Power ( ) = MRR ( ) × Specific energy ( ) = Torque ( N m ) × Rotational speed ( ) s s mm3 s Torque ( N m ) = (N) × D / 2 (m) ) 5. Compare pros and cons between focused-ion beam machining and laser beam machining.(at least five) 6. Select one item around you and guess its manufacturing process and explain why. 2 .