When the topic of energy efficiency comes up, energy-efficient machine tools don’t immediately spring to mind. Yet machine tools contain motors and auxiliary components whose energy demand varies widely during machining operations.
Machine tools are complex power-driven industrial devices employed to manufacture ready-for-use parts or semi-finished products. Encompassing a whole array of tools for cutting and forming metal, wood and plastics, and all their accessories, machine tools are used by companies in a variety of sectors like the automotive industry, general machinery, precision engineering, the medical sector, transport, aerospace, and dies and mould.
As natural resources become scarce, environmental performance criteria for machine tools need to be defined and the use of these criteria specifiedMachine tools obviously use different forms of energy, such as electrical energy, compressed air, hydraulic energy, energy hidden in the cooling and lubrication system, etc. Therefore, the energy demand of a machine tool is considered as key data for investment, but does not stand alone. The performance of a machine tool is multidimensional regarding its economic value, its technical specification and its operating requirements, which are influenced by the specific application.
ISO has recently published the first two parts of a new International Standard for the environmental evaluation of machine tools, which proposes to analyse machine tools with regard to the delivered functions in order to highlight the commonalities in the huge variety of existing machine tool types.
ISO 14955-1, Machine tools – Environmental evaluation of machine tools – Part 1: Design methodology for energy-efficient machine tools
ISO 14955-1:2017 constitutes the application of eco-design standards to machine tools, mainly for automatically operated and/or numerically controlled (NC) machine tools.
ISO 14955-1:2017 addresses the energy efficiency of machine tools during the use stage, i.e. the working life of the machine tool. Environmentally relevant stages other than the use stage and relevant impacts other than energy supplied to machine tools are not within the scope and need special treatment (e.g. according to ISO/TR 14062). Elements of eco-design procedure according to ISO/TR 14062 are applied to machine tools. Reporting of results to users and suppliers and monitoring of results are defined.
ISO 14955-2, Machine tools – Environmental evaluation of machine tools – Part 2: Methods for measuring energy supplied to machine tools and machine tool components
This document describes how measurements are made by providing measuring methods in order to produce reproducible data about the energy supplied to a machine tool under specified conditions. Furthermore, it provides methods to quantify the energy supplied to components in order to assign their share to generalized machine tool functions as described in ISO 14955‑1. It supports the energy-saving design methodology according to ISO 14955‑1 by providing measuring methods for the energy supplied to machine tools.
The assignment of the energy supplied to machine tool functions requires measurements at machine tool component level. These measurements need to be reproducible and independent of conditions other than those being recorded and documented.