The document provides an overview of Automatically Programmed Tools (APT) language used for numerical control part programming. It describes the four types of statements in APT - geometry statements to define geometric elements, motion statements to describe tool paths, postprocessor statements with machine-specific codes, and auxiliary statements for tolerances. Geometry statements use symbols and keywords to define points, lines, circles, and planes. Motion statements include basic point-to-point and contouring commands to control the tool.

1. AUTOMATICALLY PROGRAMMED TOOLS
(APT)
Submitted by:
Amit Kumar Chauhan
MT13IND001

2. INTRODUCTION OF APT
 The APT language was the product of MIT development work on NC
programming systems.
 Its development began in June 1956, and it was first used in production
around 1959.
 Today it is the most widely used language in NC part programming.
 Although first intended as a contouring language , modern versions of APT
can be used for both positioning and continuous path programming.

3. TYPES OF STATEMENTS IN APT
The four types of statements in the APT language are:
1. Geometry Statements: which define primitive elements such as points,
lines, circles, planes, cones and spheres. They are also sometimes called
definition statements
2. Motion Statements: which describe the tool path in relation to the part
geometry
3. Postprocessor Statements: which give specific machine tool code
information as well as feeds and speeds
4. Auxiliary Statements: which give part and tool tolerances

4. 1. GEOMETRY STATEMENTS
 The general form of geometry statements is:
symbol = geometry type / descriptive data
An example of such statement is:
P1 = POINT/100.0, 200.0, 300.0
 The statement is made up of three sections.
 The first is the symbol use to identify the geometric element. Normally the
alphabet “P” is used for defining a Point, “C” for Circle, “L” for Line and
“Pl” for Plane.
 The second section of the geometry statement is an APT vocabulary word
that identifies the type of geometry element. e.g. POINT, LINE, CIRCLE,
PLANE, etc.
 The third section of the geometry statement is the descriptive data

5. DEFINITION OF POINT-1:
( COORDINATE VALUES )
P1 = POINT/2,2,2
X
Y
P1
2
2

6. DEFINITION OF POINT-2:
(INTERSECTION OF TWO PREVIOUSLY DEFINED
LINES)
P2 = POINT / INTOF,L1,L2
P2
L2
L1

7. DEFINITION OF POINT-3:
(INTERSECTION POINT OF A PREVIOUSLY DEFINED LINE
AND CIRCLE)
P3 = POINT / XSMALL, INTOF, L1, C1
Or P3 = POINT / YSMALL, INTOF, L1, C1
P4 = POINT / XLARGE, INTOF, L1, C1
Or P4 = POINT / YLARGE, INTOF, L1, C1
P3
C1
L1
P4
Y
X

8. DEFINITION OF POINT-4:
(INTERSECTION POINT OF TWO PREVIOUSLY
DEFINED CIRCLES)
P3 = POINT / XSMALL, INTOF,C1,C2
Or P3 = POINT / YLARGE, INTOF, C1,C2
P4 = POINT / XLARGE, INTOF, C1,C2
Or P4 = POINT / YSMALL, INTOF, C1,C2
P3
P4
C1
C2
Y
X

9. DEFINITION OF POINT-5: (ON THE CIRCUMFERENCE
OF A PREVIOUSLY DEFINED CIRCLE )
P2 = POINT / C1,ATANGL,75
P2
X
C1
75°

10. DEFINITION OF POINT-6:
(CENTER POINT OF A PREVIOUSLY DEFINED CIRCLE
)
P2 = POINT / CENTER, C1
C1
P2

11. DEFINITION OF LINE-1:
(PASSING THROUGH TWO PREVIOUSLY DEFINED
POINTS)
L1 = LINE/P1,P2
L1P2
P1

12. DEFINITION OF LINE-2:
(PASSING THROUGH A PREVIOUSLY DEFINED POINT AND
TANGENT TO A PREVIOUSLY DEFINED CIRCLE)
L3 = LINE / P1, RIGHT, TANTO, C1
L4 = LINE / P1, LEFT, TANTO, C1
The RIGHT or LEFT modifiers are applied by looking from the point to the
circle and deciding whether the line will pass to the right or left of the circle.
P1
C1
L3
L4

13. DEFINITION OF LINE-3:
(TANGENT TO TWO PREVIOUSLY DEFINED CIRCLES)
L1 = LINE / LEFT, TANTO, C1, LEFT, TANTO, C2
L1 = LINE / RIGHT, TANTO, C2, RIGHT, TANTO, C1
The RIGHT & LEFT modifiers are applied looking from the first circle
quoted to the second
L1
C2
C1

14. DEFINITION OF LINE-3: CONTD.
(TANGENT TO TWO PREVIOUSLY DEFINED CIRCLES)
L3 = LINE / LEFT, TANTO, C1, RIGHT, TANTO, C2
L4 = LINE / RIGHT, TANTO, C1, LEFT, TANTO, C2
C1
L4
L3
C2

15. DEFINITION OF LINE-4:
(PASSING THROUGH A PREVIOUSLY DEFINED POINT AT A
SPECIFIED ANGLE TO THE X-AXIS)
L2 = LINE / P1, ATANGL, 30
L2 = LINE / P1, ATANGL, -150
L2
30°P1
150°
Y
X

16. DEFINITION OF LINE-5:
(PASSING THROUGH A PREVIOUSLY DEFINED POINT,
PARALLEL TO A PREVIOUSLY DEFINED LINE)
L3 = LINE/P3,PARLEL,L2
L3
P3
L2

17. DEFINITION OF LINE-6:
(PASSING THROUGH A PREVIOUSLY DEFINED POINT,
PERPENDICULAT TO A PREVIOUSLY DEFINED LINE)
L3 = LINE/P1,PERPTO,L2
L3
L2
P1

18. DEFINITION OF CIRCLE-1:
(COORDINATES OF CENTER OF CIRCLE, WITH A GIVEN
RADIUS)
C1 = CIRCLE/X,Y,R
(X,Y)
C1
R

19. DEFINITION OF CIRCLE-2:
(PREVIOUSLY DEFINED CENTER POINT AND TANGENT TO
A PREVIOUSLY DEFINED LINE)
C2 = CIRCLE/CENTER,P1,TANTO,L2
P1
C2
L2

20. DEFINITION OF CIRCLE-3:
(PREVIOUSLY DEFINED CENTER POINT AND PASSING
THROUGH ANOTHER PREVIOUSLY DEFINED POINT)
C2 = CIRCLE/CENTER,P1,P2
P1
C2
P2

21. DEFINITION OF CIRCLE-4:
(PASSING THROUGH THREE PREVIOUSLY DEFINED
POINTS)
C3 = CIRCLE/P1,P2,P3
C3
P2
P3
P1

22. DEFINITION OF PLANE:
(BY THREE PREVIOUSLY DEFINED POINTS)
PL4 = PLANE/P1,P2,P3

23. 2. MOTION STATEMENTS
 APT motion statements have a general format:
motion command / descriptive data
e.g. GOTO / P1
 At the beginning of the motion statements tool must be given a starting
point
FROM / P0
Or FROM / -2, -2, 0
 The FROM is an APT vocabulary word which indicates that this is the
initial point from which others will be referenced. The FROM statement
occurs only once at the start of the motion sequence.
 In APT there are two basic types of motion statements:
a) Point to Point motion
b) Contouring motion

24. A) POINT TO POINT MOTION
 There are only two basic point to point motion commands
GOTO:
The GOTO statement instructs the tool to go to a particular point location
specified in the descriptive data.
e.g. GOTO / P2
GOTO / 2, 7, 0
GODLTA:
The GODLTA command specifies an incremental move for the tool.
e,g, GODLTA / 2, 7, 0 instructs the tool to move from its
present position to 2 units in x-direction, 7 units in y-direction and 0 units
in z-direction

25. B) CONTOURING MOTION
 In contouring motion commands the tool position must be continuously
controlled throughout the move. For contouring movements, the tool is
directed along intersecting surfaces. These surfaces have specific names in
APT.

26.  Drive Surface (DS): the surface against which the edge of tool rides.
 Part Surface (PS) : the surface on which the bottom end of the tool rides.
 Check Surface (CS) : the surface at which the tool motion is stop.

27. HOW TO APPROACH THE CHECK
SURFACE
 Modifier words, such as TO, ON, PAST or TANTO, are used to govern the
position of the tool in relation to the check surface.

28. HOW TO USE THE DRIVE SURFACE
 Motion statements, GOLFT (go to the left), GOFWD (go forward) and
GORGT(go to the right), are also used to control the cutter motion.

29. 3. POST PROCESSOR STATEMENT
Post processor command for a particular tool are :
MACHIN/ : use to specify the machine tool and call the post processor for the tool.
e.g.- MACHIN/DRILL,3
COOLNT/ : allow the coolant fluid to be turned on or off.
e.g.- COOLNT/OFF
COOLNT /ON
COOLNT/FLOOD
COOLNT/MIST
FEDRAT/: specifies the feed rate for moving the tool along the part surface in
inches per minutes:
e.g.- FEDRAT/4.5
SPINDL/: gives the spindle rotation speed in revolution per minute.
e.g.- SPINDL/ 850
FINI: end of program

30. 4. AUXILIARY STATEMENTS
• It give part and tool tolerances.
• The statement used for this are
INTOL/0.0015
OUTTOL/0.001

31. Thank you