Automatic set-up

Confidence in machine tool build quality has risen to the point that there is now a strong drive towards fully traceable 'on-machine' measurement for process control and verification. This in turn has opened the door for 24-hour, seven-day-a-week unmanned machining strategies.

Unlike full verification, which generally requires a complete co-ordinate-measuring machine (CMM) inspection of the component, process verification focuses on critical areas that would govern the 'health' of subsequent machining processes or determine whether a billet/casting is positioned so that it can be machined within the required constraints of the program.

If these are within the process limits the rest of the machining processes can be relied on to be correct, as can the process control used to oversee the manufacturing as a whole. Naturally, the best results require that the machines are well maintained and mapped so that an understanding is gained of temperature-related drift and positioning anomalies.

On the other hand, process verification has its sceptics, and is often subject to considerable criticism, chiefly on account of established arguments. These include 'doing anything but cutting on a machine tool wastes precious time' and 'you should never measure a part using the same machine that made it.'