Volumetric compensation for precision manufacture through a standard CNC controller

Volumetric performance is replacing axis accuracy as the accepted measure of machine tool positioning performance. Long-term, multinational projects, such as the manufacture and maintenance of modern aircraft, require comparable machining performance for any machine used by any member of the supply chain throughout the world, for the duration of the project. Standards for measurement, such as ISO 230, and methods of evaluation of volumetric accuracy [1] are imperative in order to ensure each machine conforms to the required tight machining tolerances.
Having established a volumetric accuracy figure for a process, it is the responsibility of the machine tool builder to provide equipment capable of achieving the requisite accuracy throughout the volume. Misalignments,
necessary clearances and imperfections during manufacture and assembly mean that a machine cannot be perfectly built, but error avoidance techniques [2] can be implemented to minimize the resultant error.
Good mechanical design and build practices should always be followed, with the limiting factor being the likely increased cost of implementing such a strategy. Compensation of the remaining errors can be a relatively inexpensive means of improving performance.