2. 03/30/15
Numerical Control
Numerical Control is the operation of a
machine using coded instructions which
consists of letters, numbers, punctuation
marks, and other symbols. This coded
information is known as the Part Program
These types of systems are referred to as
“hardwire controls” and were popular from
the 1950’s to 1970’s.
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Engineering design of a part
Develop manufacturing plan for the
part
Program numerical control
instructions to allow the part to be
manufactured according to the plan
Process the program to develop
cutter location data set
Post Process for a specific machine
tool
The basic NC
Process
From Bedworth et
al. 1991
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Computer Numerical Control
CNC
NC machine with a microprocessor as an
integral part of the MCU. Data handling, control
sequences, and response to input is determined
by the integrated microprocessor.
Started in the 1970s
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CNC Advantages
Increased Program storage capability at the machine
Program editing at the machine
Control systems upgrades possible
Option -resident CAM system at machine tool
Tool path verification
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Part Programming
APT (Automatically Programmed Tool) is a
software compiler for simplifying numerical
control Programming.
Developed by MIT in 1959
APT is the most widely used processor
8. 03/30/15
APT
APT (Automatically Programmed Tool) is a
software compiler for simplifying numerical
control Programming.
Developed by MIT in 1959
APT is the most widely used processor
9. 03/30/15
APT Characteristics
•Three-dimensional unbounded surfaces and
points are defined to represent the part to be made
•Surfaces are defined in a X-Y-Z coordinate
system
•In Programming, the tool does all the moving; the
part is stationary.
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APT NC Words (Codes)
N Code - Sequence Number
G Code - Control Functions
F Code - Feed Rate
S Code - Spindle Speed
T Code - Tool Selection
M Code - Miscellaneous functions
X, Y, Z Code - Coordinate position
16. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.0 Z0.0 S500 M04
G57 PS0
G00 Rapid movement (no cutting)
X26.0 X location (as a diameter; 13 form zero)
Z0.0 Z location
S500 Spindle speed is 500 rpm
M04 Rotate spindle counterclockwise
APT Program Interpretation
x
z
(0,0) +ve
+ve
17. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
G01 Linear interpolation (cutting)
X-0.20 Move only in x direction until you pass
the center by 0.1 mm (facing)
F100 Set feed rate to 100 mm/min.
APT Program Interpretation
18. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
G00 Move rapidly away from workpiece (no cutting)
Z2.0 the movement is 2 mm away from the face.
APT Program Interpretation
19. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
Go to a safe location away from the
workpiece [x = 50 (25 from zero), z = 50] to
change the tool.
APT Program Interpretation
20. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
N0060 T0404
T0404 Select tool number 404
Since we are using the same tool (404)for
both turning and facing, N0050, N0060 are
not needed
APT Program Interpretation
21. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
N0060 T0404
N0070 G57 G00 X25.00 Z2.0 S500 M04
G57 PS0
G00 Rapid movement (no cutting)
X25.0 X location (as a diameter; 12.5 form zero)
Z2.0 Z location
S500 Spindle speed is 500 rpm
M04 Rotate spindle counterclockwise
APT Program Interpretation
22. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
N0060 T0404
N0070 G57 G00 X25.00 Z2.0 S500 M04
N0080 G01 X22.5 Z-70.0 F100
G01 Linear interpolation (cutting)
Z-70 Move only in z direction (external turning)
F100 Set feed rate to 100 mm/min.
APT Program Interpretation
23. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
N0060 T0404
N0070 G57 G00 X25.00 Z2.0 S500 M04
N0080 G01 X22.5 Z-70.0 F100
N0090 G00 X26.0 Z2.0 S500
G00 Move rapidly away from workpiece (no cutting) to
location x= 26.0 (13.0 from zero) and z = 2.0.
APT Program Interpretation
24. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
N0060 T0404
N0070 G57 G00 X25.00 Z2.0 S500 M04
N0080 G01 X22.5 Z-70.0 F100
N0090 G00 X26.0 Z2.0 S500
N0100 G84 X17.5 Z-20.0 D0=200 D2=200 D3=650
G84 Turning cycle for machining the step
X17.5 final diameter
Z-20 length of step is 20 mm
D0=200 Finish allowance in X direction (0.2 mm)
D2=200 Finish allowance in Z direction (0.2 mm)
D3=650 Depth of cut in each pass (0.65 mm)
APT Program Interpretation
25. 03/30/15
O0013
N0010 T0404
N0020 G57 G00 X26.00 Z0.0 S500 M04
N0030 G01 X-0.20 F100
N0040 G00 Z2.0
N0050 X50.0 Z50.0
N0060 T0404
N0070 G57 G00 X25.00 Z2.0 S500 M04
N0080 G01 X22.5 Z-70.0 F100
N0090 G00 X26.0 Z2.0 S500
N0100 G84 X17.5 Z-20.0 D0=200 D2=200 D3=650
N0110 G00 Z2.0
G00 Move rapidly away from workpiece (no cutting)
Z2.0 the movement is 2 mm away from the face.
APT Program Interpretation
37. 03/30/15
Program Interpretation
G55 X200 Y80
Program 1
N001 M06 T1
N002 M03 rpm 400
N003 G01 X-8 Y0 Z0 XYFeed 150
N004 G01 X-8 Y0 Z-0.5 ZFeed 150
Lower the end mill to determine the depth of
cut
38. 03/30/15
Program Interpretation
G55 X200 Y80
Program 1
N001 M06 T1
N002 M03 rpm 400
N003 G01 X-8 Y0 Z0 XYFeed 150
N004 G01 X-8 Y0 Z-0.5 ZFeed 150
N005 G01 X70 Y0 Z-0.5 XYFeed 75
Move from the lower left corner
of the work piece to the right
lower one cutting with
feed=75mm/min
39. 03/30/15
Program Interpretation
G55 X200 Y80
Program 1
N001 M06 T1
N002 M03 rpm 400
N003 G01 X-8 Y0 Z0 XYFeed 150
N004 G01 X-8 Y0 Z-0.5 ZFeed 150
N005 G01 X70 Y0 Z-0.5 XYFeed 75
N006 G01 X70 Y60 Z-0.5 XYFeed 75
Move from the lower left corner
of the work piece to the right
lower one cutting with
feed=75mm/min