CNC Machines MCQs Quiz Multiple Choice Questions & Answers

1. A CNC machine find widest applications in the field of

1. Mask production
2. Nonconventional machining
3. none of the above
4. small lot and batch production

2. A CNC machine tool has a continuous part control both linear and circular along X, Y, Z and control of table rotation about X axis and Z axis, so the machine should be called

1. 3L, 2C
2. 5C
3. none of the above
4. 2C, L

3. A CNC milling machine would have

1. Point-to-point closed loop control only
2. Countering control
3. none of the above
4. Point-to-point open loop control only

4. A machine will be said to have CNC control if

1. The tool motion is guided by drum cams and disc cams
2. the loading and unloading of the work piece ON and OFF the machine respectively is made automatic
3. control is achieved by employment of alphanumeric data
4. The dimensions of the work piece are measured by sensors while cutting is going on

5. CNC is not applicable in

1. Milling machine
2. Lathe
3. none of the above
4. Drilling machine

6. CNC machining has the following main advantage over conventional machining practice

1. feedback control
2. flexibility
3. none of the above
4. ability to employ higher cutting speeds, feeds and depth of cut

7. The main advantage of computer numerical control over conventional automatic control which is referred to sometimes as fixed automation is

1. CNC allows for application of higher cutting speeds and feeds
2. CNC is applicable in unmanned satellites
3. CNC offers higher flexibility than conventional automatic control (fixed automation)
4. CNC is stylish while automatic conventional control is not

8. For milling a bilaterally symmetrical 2-D profile on metal plate 10 millimetres thick, a CNC milling machine would require the following accessory or attachment

1. Dividing head
2. Reversing table
3. none of the above
4. Copy milling attachment

9. Holes are to be drilled on the circumference of a circle with regular angular spacing. If a CNC machine is used it should essentially

1. Have a CNC rotary axis of motion to rotate the table, about Z-axis (inaddition to X, Y and Z axes of rotation)
2. Be a CNC milling machine with contouring control
3. none of the above
4. Have one indexing head mounted on the machine table

10. In a CNC machining centre, any complex cutting motion involving X, Y and Z moments is carried out by

1. skill of the machine operator
2. combinations of movements obtained from motors along the axis
3. none of the above
4. Use of jigs, cams, templates and tracers

11. In a CNC milling machine, a circular cutter is always produced, by

1. by copy milling
2. by combine motion of feed axis
3. none of the above
4. by operators skill and experience

12. What is the purpose of using recirculating ball screw nut mechanism in CNC machine

1. for higher surface finish
2. for carrying out up-milling
3. to remove backlash
4. to reduce the setup time

13. In a CNC turning centres, threads of different pitches are cut by

1. Different settings of the feed gearbox
2. Different settings of the speed gearbox
3. none of the above
4. Different settings of the meander drive and Norton Tumbler gears

14. In a point-to-point feed axis employing a stepper motor as a prime mover

1. an interpolator is a must
2. a tachogenerator is a must
3. none of the above
4. an encoder for position feedback is a must

15. In computer controlled machine tools terminal clergy, machining centre is

1. the centre of the cutter which actually goes to the programmed point when used without radius compensation
2. a computer-controlled machine tool capable of a variety of operations involving rotating cutters
3. none of the above
4. the origin of the machine coordinate system with respect to which the operator has to make his program

16. In computer-controlled machine tools, tool movements are controlled by

1. machine operator
2. foolproof mechanism
3. none of the above
4. Cam

17. In order to produce a circular group in milling in CNC machining centre

1. a planetary gear mechanism which actuates the table moment
2. a rotary table is necessary
3. none of the above
4. a universal dividing head is necessary

18. Interpolator is present in case of

1. point-to-point closed loop system
2. contouring control system
3. none of the above
4. Point-to-point open loop system

19. On the CNC lathe

1. 3-D programming is necessary
2. 1-D programming is sufficient
3. none of the above
4. 2-D programming is sufficient

20. The function of the tachogenerator is

1. faster response of the motor
2. to make 3-D interpolation possible
3. none of the above
4. reduction of basic length unit

21. The incremental encoder is capable of sensing

1. direction of rotation of the lead screw
2. direction of rotation of the motor
3. none of the above
4. direction of movement of the table