HEIDENHAIN TNC 370 - Fundamentals; Cartesian Coordinate System; Conversational Programming; Introduction

1 Introduction
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1.2 Fundamentals
Introduction
This chapter addresses the following topics:
l What is NC?
l The part program
l Programming
l Reference system
l Cartesian coordinate system
l Additional axes
l Polar coordinates
l Setting a pole
l Datum setting
l Absolute workpiece positions
l Incremental workpiece positions
l Programming tool movements
l Position encoders
l Reference mark evaluation
What is NC?
NC stands for Numerical Control. Simply put, numerical control is the
operation of a machine by means of coded instructions. A modern
control such as the TNC 370 has a built-in computer for this purpose
and is therefore also called CNC (Computerized Numerical Control).
The part program
A part program is a complete list of instructions for machining a work-
piece. It contains such information as the target position of a tool
movement, the tool path - i.e. how the tool should move towards the
target position - and the feed rate. The program must also contain
information on the radius and length of the tools, the spindle speed and
the tool axis.
Conversational programming
Conversational programming is an especially easy way of writing and
editing part programs. From the very beginning, the TNCs from HEI-
DENHAIN were developed specifically for shop-floor programming
by the machinist. This is why they are called TNC, for Touch Numerical
Controls. You begin programming each machining step by simply
pressing a key. The control then asks for all further information required
to execute the step. You can also program the TNC 370 in IS0 or in
DNC mode.
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TNC 370 -