CNC Cutting Machine Practice Test

How is the control resolution of a table calculated?

1. By multiplying pitch with total steps

2. By dividing pitch by points per revolution

3. By adding steps to the pitch of the screw

4. By finding the average distance per motor rotation

The correct answer is: By dividing pitch by points per revolution

The control resolution of a table in CNC machining is primarily determined by the relationship between the pitch of the lead screw and the steps taken by the motors. The correct method for calculating control resolution involves dividing the pitch (the distance the table moves per revolution of the screw) by the number of steps the motor takes to complete one revolution, also referred to as points per revolution. This calculation gives a precise understanding of how far the cutting tool moves with each motor step, thus defining the resolution. For example, if a screw has a pitch of 5 mm and the motor has 200 steps per revolution, the calculation results in a control resolution of 0.025 mm per step (5 mm divided by 200 steps). This precision is crucial for accurate cutting and machining processes. The other choices do not accurately reflect the relationship needed for calculating control resolution. For instance, multiplying pitch with total steps would yield a total travel distance rather than resolution per step, adding steps to pitch mixes unrelated units, and averaging distance per motor rotation does not consider the defined steps impacting movement precision directly.