Development Of CNC Machine PerformanceStandards

Abstract

This paper summarises our approach to a new EU project to investigate current and proposed ISO machine tool standards by conducting tests on a range of CNC machine tools to investigate and report on the feasibility of improvements to existing test procedures. A partnership of six EU companies has been established to review the limitations of current test procedures, and to investigate possible enhancements that may be required. This paper summarises some of the preliminary work which has led to the establishment of this new project. It is submitted as part of an ongoing discussion procedure to gather suggestions for enhancements that can be examined during the two years of the project. Some preliminary results are shown to assist these discussions. Current ISO machine tool standards position We have briefly listed the current standards that are used, and shown when they are due for revision. Revisions always take several years of consultation to be considered and issued as a proposed standard, then issued as Drafts for Public comment (DC). After comments are received from the engineering community at large they are then reconsidered and issued as Draft ISO standards (DIS), and again circulated for further comment After that stage a standard is issued as a Final Draft Standard (FDIS), for final acceptance after a final round of comments.[l] ISO 230-2 Accuracy & Repeatability Current standards are well defined for 'normal' sized machining centres (i.e. axis lengths up to 2 metres), but do not give acceptable procedures for large machines. It is now apparent that Transactions on Engineering Sciences vol 23, © 1999 WIT Press, www.witpress.com, ISSN 1743-3533