Improvement of Ring Frame Spindle Utilization in Cotton Short Staple Spinning: A Case Study of a Cotton Spinning Mill

Abstract

Spinning mills play a very significant role in backward integration of the textile value chain by converting fibres into yarn for fabric production. Ring spinning is the most widely used short staple cotton spinning system to produce yarn from cotton fibers and is used by 7 of the 8 spinning mills. Ring spinning mills have been operating at low spindle utilisation between 67 to 80% which is below the recommended standard norm of 98% resulting to yarn production loss occurring from frequent stoppages of the ring frame and increase in the number of spindles running without producing yarn. This results in low spindle utilisation of the mill which reduces the ring frame spindle hours used for yarn production. The overall objective of this study was to improve ring frame spindle utilisation in terms of spindle hours utilized for yarn production in cotton short staple spinning, by carrying out a case study in cotton spinning mill. The specific objectives were to analyse ring spinning process production parameters, evaluate the factors affecting ring frame spindle utilisation and formulate a productivity improvement method for spinning mills. The Research design adopted by this study was a descriptive and quantitative case study. Pareto analysis was used to classify ring frame production losses based on Overall Equipment Effectiveness (OEE) classification of major losses and Ishikawa diagram used to carry out Root Cause Analysis of main causes of production loss. Failure Mode and Effects Analysis (FMEA) technique was used to map the failures which occurred within the process that contributed to production loss which were ranked using their Risk Priority Numbers (RPN). A questionnaire based on Grunberg (2007) Performance Improvement Method (PIM) was used to analyse and evaluate mill production and management practices. A production improvement method was recommended using 7level evaluation criteria of the PIM technique. Pareto analysis revealed that Idling and minor stoppages accounted for 63% losses while breakdown accounted for 22.8% of losses. Root Cause Analysis (RCA) identified use of manual doffing, lack of time awareness, and delay in replacement of empty bobbins as significant factors that affected ring frame doffing stoppage loss. It was recommended that a standardized procedure based on Single Minute Exchange of a Die (SMED) technique for the doffing procedure would yield the highest results in minimizing ring frame stoppage. A key finding from the study showed that utilisation of equipment for production in manufacturing was not just the overall time the machine was running but about standardization of the entire process of production to maximize utilization of the machine for output. Through this study spinning mills can apply the recommendations to improve ring frame productivity in order to reduce the cost of production and improve their competitiveness.