Analysis of breakdowns and improvement of preventive maintenance on drawframe machines :

Abstract

Maintenance is the actions necessary for retaining or restoring a piece of equipment, machine or system to the specified operating conditions to achieve maximum useful life. Preventive maintenance is the set of plan activities that are performed on plant, equipment, machinery and systems before the occurrence of a failure in order to protect them to prevent or eliminate any degradation in their operating conditions. Production may be stopped due to many reasons like breakdown of machine, maintenance work, labour issues, and inventory problem. It is necessary to reduce the breakdown of machine or equipment in the company for efficient production to meet the demands. The main objective of this project is to analyse the breakdown and improve the preventive maintenance on drawframe machines. 'The drawframes are the last quality improvement machines in spinning process in textile industry. Breakdown history for four drawframe machines (DO/6 no. 1, DO/6 no. 2, RSB 951 no. 1 and RSB 9-51 no.2) were analysed and noticed that DO/6 no.2 and RSB 951 no.2 have higher downtime and therefore contributed major production loss to the company. Hence detailed study was carried out to minimise production The machine breakdowns were studied using different analysis and inspection tools like fishbone diagram, why-why analysis, Pareto analysis, and measures to determine the root causes of the breakdown and develop preventive corrective actions. The machine availability (MA) was determine by MTBF and MTTR. Based on the problems root cause analyses were carried to develop and improve new preventive maintenance schedule and checklist for a machine. After implementation of root cause analysis and new preventive maintenance schedule, the machine availability was increased by 2.26% and Mean time between failures (MTBF) was increased by 29.58% and Mean time to repair (MTTR) was reduced by 34.48%.

Keywords: Machine availability, Fishbone diagram; Why-why analysis, Preventive maintenance, Corrective action, Pareto analysis, Root cause analysis, Breakdown and downtime.