A 250-mm-wide strip with a thickness of 20 mm is fed through a rolling mill with two
Question:
A 250-mm-wide strip with a thickness of 20 mm is fed through a rolling mill with two powered rolls, each of radius = 200 mm. The work thickness is to be reduced to 17 mm in one pass at a roll speed of 60 rev/min. The work material has a flow curve defined by K = 280 MPa and n = 0.14, and the coefficient of friction between the rolls and the work is assumed to be 0.14. Determine if the friction is sufficient to permit the rolling operation to be accomplished. If it is, calculate the a. roll force, b. torque, and c. power.
Problem 2 A round disk of 200-mm diameter is blanked from a strip of 3.0-mm, half-hard cold-rolled steel whose shear strength = 300 MPa, and clearance allowance = 0.075. Determine a. the appropriate punch and die diameters, and b. blanking force
Problem 3 A drawing operation is used to form a cylindrical cup with inside diameter = 100 mm and height = 80 mm. The starting blank size = 150 mm and the stock thickness = 3.0 mm. Based on these data, is the operation feasible?
Problem 4 For the drawing operation of Problem 3 (Cup Drawing), the tensile strength of the sheet metal (low-carbon steel) = 300 MPa and yield strength = 175 MPa. The die corner radius = 5 mm. Determine: a. the drawing force and, b. the blank-holding force
Problem 5 A turning operation is performed on a cylindrical work part whose diameter = 150 mm and length = 500 mm. Cutting speed = 3.0 m/s, feed = 0.3 mm/rev, and depth of cut = 2 mm. Determine: a. the cutting time and, b. the material removal rate.
Problem 6 A drilling operation is performed to create a through hole on a steel plate that is 20 mm thick. Cutting speed = 0.4 m/s, and feed = 0.20 mm/rev. The 18-mm-diameter twist drill has a point angle of 120. Determine the following once the drill reaches full diameter: a. the machining time and, b. the metal removal rate