GATE Past Year Questions: Numerical Control

Try yourself: For a 3-axes CNC table, the slide along the vertical axis of the table driven by a DC servo motor via lead screw nut mechanism. The lead screw has pitch of 5 mm. This lead screw is fitted with a relative (incremental) circular encoder. The basic length unit (BLU) of the slide along the vertical axis of the table is 0.005 mm. When the table moves along the vertical axis by 9 mm. The corresponding number of pulses generated by the encoder is

[2010]

Try yourself: In a CNC feed drive, a stepper motor with step angle of 1.8 degree drives a lead screw with pitch of 2 mm. The basic length unit (BLU) for this drive is

[2008]

Try yourself: The interpolator in a CNC machine controls

[2007]

Try yourself: Match the following:
Group-I
P. G08
Q. G41
R. G01
S. G02
Group-II
1. Linear interpolation
2. Acceleration
3. Circular interpolation
4. Cutter radius compensation
P Q R S

[2006]

Try yourself: For machining the circular arc shown in the figure below on a NC machining, the interpolation parameters (I, K) and the incremental movements in the direction of the X and Z axes are programmed as

[2004]

Try yourself: Match the following​

Group I
P. G09
Q. G41
R. G01
S. G03
Group II
1. Linear interpolation
2. Retardation
3. Circular interpolation
4. Cutter radius compensation

  P Q R S

[1994]

Try yourself: A DC servomotor is directly driving an NC table. The pitch of the lead screw of the table is 5 mm. The motor rotates at 100 rpm for an applied voltage of 10 V. If the voltage speed characteristic of the motor is linear, the applied voltage for a table of 3 m/min is equal to

[1992]

Try yourself: Feed motion can be provided with stepper motors in CNC

[1991]

Try yourself: A  axis control in a typical CNC machine provides

[1990]

Try yourself: The most common interpolation methods in continuous path NC machining are

[1990]

Try yourself: If the z-axis an d x-axis o f CNC lath e are provided with straight line controls, it is possible to carry out

[1989]

Try yourself: Interpolator in a CNC machine

[2018]

Try yourself: Circular arc on a part profile is being machined on a vertical CNC milling machine, CNC part program using metric units with absolute dimensions is listed below: ............................................
N60 G01 X 30 Y 55 Z 5 F50N70
G02 X 50 Y 35 R 20N80 G01 Z 5............................................
The coordinates of the centre of the circular arc are:

[2017]

Try yourself: In a CNC milling operation, the tool has to machine the circular arc from point (20, 20) to (10, 10) at sequence number 5 of the CNC part program. If the center of the arc is at (20,10) and the machine has incremental mode of defining position coordinates, the correct tool path command is

[2015]

Try yourself: A drill is positioned at point P and its has to proceed to point Q. The coordinates of point Q in the incremental system of defining position of a point in CNC part program will be

[2015]

Try yourself: The function of interpolator in a CNC machine controller is to

[2015]

Try yourself: For the CNC part programming, match Group A with Group B :
Group A
P. Circular interpolation, counter clock wise
Q. dwell
R. circular interpolation, clock wise 
S. Point to point countering

Group B
I. G02
II. G03
III. G04
IV. G00

[2014]

Try yourself: For machining a rectangular island represented by coordinates P(0,0), Q(100,0), fl( 100,50) and S(0,50) on a casting using CNC milling machine, an end mill with a diameter of 16 mm is used. The trajectory of the cutter centre to machine the island PQRS is

[2014]

Try yourself: A CNC vertical milling machine has to cut a straight slot of 10 mm width and 2 mm depth by a cutter of 10 mm diameter between points (0, 0) and (100, 100) on-the XY plane (dimensions in mm). The feed rate used for milling is 50 mm/min. Milling time for the slot (in seconds) is

[2012]

Try yourself: In a CNC program block, N002 G02 G91 X40 Z40..., G02 and G91 refer to

[2010]

Try yourself: Match the following:
NC Code    Definition
P. M05      1. Absolute coordinate system
Q. Q01      2. Dwell
R. Q04      3. Spindle stop
S. G90      4. Linear interpolation

[2009]

Try yourself: A customer insists on a modification to change the BLU of the CNC drive to 10 microns without changing the table speed. The modification can be accomplished by

[2008]

Try yourself: The Basic Length Unit (BLU), i.e., the table movement corresponding to 1 pulse of the pulse generator, is

[2008]

Try yourself: Which type of motor is NOT used in axis or spindle drives of CNC machine tools?

[2007]

Try yourself: NC contouring is an example of

[2006]

Try yourself: The tool of an NC machine has to move along a circular arc from (5,5) to (10,10) while performing an operation. The centre of the arc is at (10,5). Which one of the following NC tool path commands performs the above mentioned operation?

[2005]

Try yourself: Which among the NC operations given below are continuous path operations?
Arc Welding (AW)
Drilling (D)
Laser Cutting of Sheet (LC)
Milling (M)
Punching in Sheet Metal (P)
Spot Welding (SW)

[2005]

Try yourself: During the execution of a CNC part program block NO20 GO2 X45.0 Y25.0 R5.0the type of tool motion will be

[2004]

Try yourself: Machining of complex shapes on CNC machine requires

[2002]

Try yourself: In finish machining of an island on a casting with CNC milling machine, an end mill with 10 mm diameter is employed, The corner points of the Island are represented by (0, 0), (0, 30), (60, 30) and (50, 0). By applying cutter radius compensation, the trajectory of the cutter will be

[2000]

Try yourself: In a point to point control NC machine, the slides positioned by an integrally mounted stepper motor drive. If the specification of the motor is 1 deg/pulse, and the pitch Of the lead screw is 3.6 mm.What is the expected positioning accuracy?

[1997]

Try yourself: With reference to NC machine, which of the following statement is wrong?

[1993]

Try yourself: In PTP type of NC system

[1992]

Try yourself:  In NC part programming spindle speed of 730 rpm will be coded by the magic -3 rule as

[1989]