Abstract:
In the textile spinning industry the operators are assigned generally multi machines. In two or three shifts working applications the operators deserve free time of 30 min for their lunch and rest needs. During this time, machines are mostly allowed to run without supervision of operator expecting the minimum loss at the efficiencies of machines. This application seems beneficial in some cases indeed. However, this application can be useless, costly and even risky in some cases too. This work aims by using simulation methodology to expose the borders of the feasible and unfeasible areas of this application. For this aim, the efficiency of spindles or machines are estimated and compared for both strategies of a) to allow the machines to running by themselves without supervision of operator and b) to shut down the all machines completely during lunch time. The parameters used in the investigation are a) the yarn (end) breaking rates which are related basically quality of material, setting and maintenance of machines, conditions of environment like humidity and temperature and b) the number of machines or spindles assigned operators. The findings obtained show that for the small yarn breaking rates and small the number of spindles, to allow the machines continuing to run without operators can be useful despite some risks. However, in case of high yarn breaking rates and high number of machines, to allow the machines to running themselves is useless and even ineffective.
