Reference no: EM1386180

1. A solid cube of copper with each side = 1.0 ft is converted into metallic powders of spherical shape by water atomization. What is the percentage increase in total surface area if the diameter of each particle is 0.004 in (assume that all particles are the same size)?

2 An orthogonal cutting operation is performed using a rake angle of 15^o. Chip thickness before the cut = 0.012 in and width of cut = 0.100 in. The chip thickness ratio is measured after the cut to be 0.55. Determine (a) the chip thickness after the cut, (b) shear angle, (c) friction angle, (d) coefficient of friction, and (e) shear strain.

3. The power required to turn a medium carbon steel is approximately 3.8 W/mm³/s. If the maximum power available at the machine spindle is 5 hp, find the maximum metal removal rate. Also find, for a cutting speed of 36 m/min and feed rate of 0.25 mm/rev, the depth of cut and the cutting force which will occur when the metal removal rate is at the maximum value [746 Watts = 1hp].

4. The outside diameter of a cylinder made of titanium alloy is to be turned. The starting diameter is 500 mm, and the length is 1000 mm. Cutting conditions are: f = 0.4 mm/rev, and d =3.0 mm. The cut will be made with a cemented carbide cutting tool whose Taylor tool life parameters are: n = 0.23 and C =400. Units for the Taylor equation are min for tool life and m/min for cutting speed. Compute the cutting speed that will allow the tool life to be just equal to the cutting time for this part.

5. In a turning operation at a cutting speed of 165m/min, cutting force is 1080 N, and the thrust force is 1000 N, the rake angle is 10^o, the shear plane angle was found to be 19^o.

i) Determine the velocity of shearing along the shear plane and the velocity of sliding at the tool-chip interface.
ii) Find the work done per minute in shearing the metal and against the friction.
iii) Show that the work input is equal to the sum of the work done in shearing and against friction.

6. A machinability rating is to be determined for a new work material using the cutting speed of 60 min tool life as the basis of comparison. For the test material (B1112 steel), test data resulted in Taylor's equation parameter values of n = 0.29 and C = 500. For the new material, n = 0.21, and C = 400. The results were obtained with using cemented carbide tooling. (a) Compute a machinability rating for the new material, (b) Compute the machinability rating for a 10 min tool life.

7. Cemented carbide inserts are used to turn a part with a length of 21.0 in and diameter = 4.0 in. The parameters in the Taylor equation are: n = 0.25 and C = 800 (ft/min). The operator and machine tool rate = $45.00/hr, and the tooling cost per cutting edge = $2.00. It takes 2.5 min to load and unload the work part and 1.50 min to change inserts. Feed = 0.015 in/rev. Determine (a) cutting speed for maximum production rate, (b) tool life, and (c) cycle time and cost per unit of product.