Introduction; General - Siemens SINUMERIK 840 User Manual

07.90
1

Introduction

1.1

General

The ever increasing rationalization and automation of manufacture makes additional demands
on numerically controlled machine tools. Measuring on the machine is one of the new tasks to
be coped with.
In order to be able:
• to use touch trigger probes,
• to use the path measuring systems of the machine for measuring actual values and
• to do without additional external electronic controls for measured value processing,
adapted functions are required in the control (CNC).
Before dealing in more detail with the measuring cycles created for measurement and
measured value processing, some practical applications for measuring on the machine are
given as an introduction to the subject.
The general purpose to be achieved by measurement on CNC turning machines and CNC
milling machines and machining centres is to detect at an early stage impermissible
dimensional deviations of the workpiece to enable suitable compensation measures to be
initiated automatically.
Dimensional deviations are due to different causes:
• Tool wear and tool clamping
• Heat effects on the CNC machine, i.e. thermal expansion of the ball screw, machine bed
or spindle head.
In addition to checking the workpiece for dimensional accuracy, measuring on a CNC machine
offers further applications:
• Detection of tool breakage
• Measuring the tool geometry
• Determination of workpiece clamping tolerances
• Compensation for factors influencing the machining process (e.g. force and temperature)
• Identifying a pallet
• Determination of the centre point of a hole.
For this wide range of measuring tasks, specially tailored programmable measuring cycles are
required putting the machine tool manufacturer and user in a position to achieve optimum
solutions to the measuring tasks to be performed on his machine tool.
©
Siemens AG 1990 All Rights Reserved
SINUMERIK 840/850/880 (BN)
6FC5197- AB70
1 Introduction
1.1 General
1–1