Towards an Optimization Calculation for Preventative and Reactive Calibration Strategies

Minimising manufacturing waste and reducing downtime are becoming increasingly important to industrial companies, especially those manufacturing with high levels of output or to a high level of accuracy, such as mobile phone, submarine, and aircraft. Increasingly, predictable output quality from machine tools relies on systematic calibration to improve and maintain their capabilities, as well as to reduce waste in terms of scrapped parts and energy from re-manufacturing. However, such calibrations remove the machine from normal manufacturing duties, which could have large financial implications.
This paper presents a cost optimisation process that is used to reduce unnecessary downtime while maintaining the machine at the required capability. The concept of this work will ultimately lead to a technically-driven management tool that can optimise the schedule of a calibration plan. In the paper we use a case study to validate the presented technique for both preventative and reactive calibration strategies. This case study shows that the calibration cost for both strategies can be decreased by intelligently reducing machine tool downtime. This results in the cost of using a preventative strategy being reduced, making it a commercially attractive alternative to reacting to failure, increasing the feasibility of using reactive calibration.