past year exam 2.1

Question

3.1. the belt drive from electric motor transmits an effective driving force of 800N to the 250mm diameter driving pulley on a milling machine. The torque to overcome friction on the driving parts of a machine can be assumed as 8Nm. Calculate the following: 3.1.1. Torque transmitted to the machine pulley 3.1.2. torque that is available at the milling cutter 3.1.3. the effective cutting force that can be executed by the 115mm diameter milling cutter 3.2. Calculate the power consumed by the following: 3.2.1. Lathe operation during which the cutting force applied to the cutting tool is 1000N and the rotational speed of the workpiece with a diameter of 350mm is 350r/min. 3.2.2. Shaper operation involving a cutting force by 750N and a stroke length of 120mm long taking 8 seconds to complete.

Answer 1

(3.1.1)

The effective driving force = 800 N.

Diameter of the driving machine = 250 mm

radius of the driving machine is (250/2) = 125mm.

Total torque transmitted by the driving pulley Torque = force * radius.

Therefore torque transmitted by machine pulley = 100 Nm.