AUTOMATIC PROGRAMMING TOOL

Prepared by:•Mehul Chauhan•Anis Dandiwala

Automatic programming tool(APT) is the most powerful, comprehensive and universal geometric processor language.

NC languages are broadly divided into three groups:

Machine tool oriented APT like Special Types

Introduction:

Machine tool Oriented system These are generally developed by the

machine tool manufactures for generating NC tapes to be used for their machine tool.

These systems are normally single pass tape preparation system with no post processors.

The examples of such languages are SPLIT (Standard Processing Languages Internally Translated), which is used for standard machine tool.

Introduction:

Introduction:APT Like systems: Since APT is the most powerful, comprehensive and

universal geometric processor language used all over the world by a large number of companies.

The basic advantages of the APT system is the versatility with which even complicated geometrical configurations of workpieces can be described.

Often, this versatility of the system becomes a great disadvantage particularly to be used for a class of components of for a particular type of machine tool.

To alleviate these disadvantages, the other system have been developed such as NELAPT,UNIAPT, EXAPT,IFAPT, ADAPT,etc.

Introduction: In the following, some features of these

languages which are different from APT are discussed.

NELAPT: NELAPT developed by the National

Engineering Laboratory, UK is a subset of APT with a few advanced features not available in APT.

Vocabulary of NELAPT is same as APT. C for CIRCLE V for VECTOR GB for GOBACK YS for YSMALL

Introduction: The storage requirements for the complete

NELAPT system is 40 k words (24 bites length)

EXAPT: The most important development of APT is

probably EXAPT (Extended subset of APT). One of the basic specifications for the EXAPT

system was that the language is to be both geometrically and technologically oriented and task for the machine tool is simplified.

Introduction: Further ,three versions of EXAPT are

available:EXAPT-1: For positioning machines,

such as drilling.EXAPT-2: For turning centers.EXAPT-3: For milling operations for

straight line and continuous path control system.

Introduction:Special Types: All the other tape preparation language that

will not fall into the above two categories are grouped into this. There is a large variety in this category such as GNC,ELAN, GTL, TAPEPREP, NUFORM, QUICK-PATH,GENESIS, VNC,GETURN, COMPACT-2,TOOLPATH, etc.

Introduction:GNC: It is Graphical Numerical Control. It was

developed to provide an easy to use interactive tape preparation system.

This system has been implemented on a large number of computer systems.

The system consists of following modules from among which the user can make out a system that is suited for his purpose.

Introduction: Geometry definition module (k curves) Turned parts definition module Macro facility Machining definition module Lathe module Milling,drilling,flame cutting module Plotting module Post processors

Introduction: The complete APT programming consist of

the following four types of statement : Geometry Motion Post Processor Compilation Control

APT GEOMETRY:

The point geometry is normally broken into a number of surface elements that could be defined from the data given in a part print.

In this section, we would discussed the geometrical definition which are more generally used.

With these geometrical definitions ,it is possible to define most of the parts except for the very complex ones.

Before we discussed the geometric definition it is pertinent to explain some convention that are followed in presenting the information in the definitions.

APT GEOMETRY:

For each of the definitions the general form is presented in which the following rules are observed:

I. The symbol in lower case letters underlined represents the surface type specified,

II. A symbol in lower case letter without underline represent a scalar,

III. The word shown in the upper case letters are the MINOR keywords,And

IV. All possible modifier are presented one below the other enclosed by an opening brace from among which only one appropriate for the definition is to be selected.

APT GEOMETRY: In the figures ,the defined geometry

elements are shown as solid lines and all other possible geometric elements as shown in Broken lines.

Any geometrical element may be definable from more than one definition, in which case a part programmer should choose the one which simple and involves least amount of computation.

APT GEOMETRY: Nesting: The geometrical definition or arithmetical computations

can be nested wherever necessary .The nested definition is a definition enclosed in parentheses and then inserted in another statement, e.g.

PL2=PLANE/P1 ,P2, P3 Similarly, arithmetic computation in necessary during the

geometric definitions or in any other statements can also be nested.e.g.

P2=POINT/(25-12*COS(35)0,(12-6*SIN(35)). Too much of nesting in a single statement would make it

unnecessarily long and is likely to be error prone and as such it is not advisable to indulge in unnecessary nesting.

APT GEOMETRY: ZSURF: ZSURF specifies a plane which is to be used

to provide a Z value for every subsequent point definition in which no Z value has been specified.

ZSURF may be redefined within a part program, where ZSURF is not sepcified,all point definitions which have no Z value specified are given a Z value equal to zero.

APT GEOMETRY: GEOMETIC COMMANDS:o POINT o LINEo CIRCLEo PLANEo VECTORo PATTERNo SPHEREo GCONIC o TABCYL

APT GEOMETRY: LINES: Syntax : <Symbol>=LINE/<parameter

string>. Lines do not have a direction and are of

infinite length. Lines must not be perpendicular to the XY plane. Lines are planes perpendicular to the XY plane.

APT GEOMETRY:

APT GEOMETRY: CIRCLES: Syntax: <Symbol>=CIRCLE/<parameter

string> A circle is always considered as a circular

cylinder perpendicular to the XY plane of infinite height.The radius value must not be negative.

APT GEOMETRY:

APT GEOMETRY: