1. COMPUTER ASSISTED PART PROGRAMMING
The alternative to manual part programming is the use of high-
level programming language, which:
Defines the geometry part in terms of basic geometry
elements (points, lines …)
Instructs the machine about the cutting tool
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2. APT LANGUAGE
The most comprehensive and widely used language is Automatically
Programmed Tool (APT) – the first prototype of the APT system was
developed at MIT in 1956.
The APT statements belong to one of the five types:
Identification statements
Geometry statements
Motion statements
Post-processor statements
Auxiliary statements
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4. APT LANGUAGE
Geometry statements, the general form of geometry statement is:
Symbol = geometry type/descriptive data
In the case of points:
P1 = POINT/X, Y, Z
In the case of Line:
L2 = LINE/P1,P2
In the case of plane:
PL3 = PLANE/P2,P3,P5
In the case of circle:
C4 = CIRCLE/CENTRE, P6, RADIUS, 10.0
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16. 17
Motion statements, with regard to point-to-point
operation there are three motion statements for
positioning the tool at a desired point:
Syntax:
Motion command/descriptive data
FROM/point_location
GOTO/point_location
GODLTA/Δx, Δy, Δz
17. 18
Start point :
FROM/TARG or FROM/x, y, z
Cutter:
CUTTER/dia
Tolerances :
INTOL/0.005
OUTTOL/0.005
Set up commands
18. 19
Point to point motion
GOTO/point GOTO/P7 GOTO/2.0, 5.0, 0.0
GODLTA/dx, dy, dz GODLTA/1.0, 2.0, 0.0
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GO/{TO}, Drive surface, {TO} Part surface, {TO},
Check surface
Or
GO/{TO}, Drive surface, {TO} Part surface, {TANTO},
Check surface
…And the same with PAST or ON instead of TO
GOLFT/
GORGT/
GOUP/
GODOWN/
GOFWD/
GOBACK/
For example:
GO/TO, L1, TO, PS, TANTO, C1
GO/PAST, L1, TO, PS, TANTO, C1
21. 22
The effect of the motion modifiers words are shown in below fig.
23. 24
Auxiliary commands
CLPRT -Obtain the computer print out of cutter location sequence on
the cnc tape
FINI -indicate the end of the computer program
PARTNO- used at start of program to identify the part program
41. OTHER PART PROGRAMMING LANGUAGES
ADAPT (ADaptation APT) was the first attempt to adapt APT
programming system for smaller computers
AUTOSPOT (AUTOmatic Sytem for POsitioning Tools) was
developed by IBM and first introduced in 1962
EXAPT (EXtended subset of APT) was developed jointly in
German in about 1964 by several universities to adapt APT for
European use. It is compatible with APT and thus can use the
same processor as APT
COMPACT was developed by Manufacturing Data Systems,
Inc. (MDSI)
SPLIT (Sundstrand Processing Language Internally
Translated) was developed by Sundstrand Corporation,
intended for its own machine tools
MAPT (Micro-APT) is a subset of APT, to be run on the
microcomputers
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