Maintenance optimization using fuzzy logic and delay time model
摘要
The downtime experienced in the Nigerian manufacturing sector has become a threat to its existence because of the huge cost implications. Despite the different strategies adopted, the results have not been very promising. Research into organizational production data showed that the root causes of breakdowns are predominantly man and method, which are both measures of the organizational workforce capability. Skill and attitude are factors that affect a technician’s probability of perfect inspection (PPI) in the field. A fuzzy logic rule-based system quantifies the measured skill and attitude to obtain the corresponding PPI. The outcome from the fuzzy logic system was used to evaluate the expected downtime as well as the optimal inspection interval through the application of the delay time model (DTM). The delay time model accounts for the human factor in carrying out inspection and repair, which has a significant effect on the overall downtime proportion. The results from the case study showed that as the capability required for proper maintenance drops, there is a sharp increase in the proportion of downtime from breakdowns and repairs. This highlights the impact that the organizational workforce has in bridging the gap between the expected results from an adopted maintenance model.