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Abstract:
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In recent years, textile mills have been faced with
the problems of high labor turnover and absenteeism. This
has been a particularly serious problem among spinning frame
doffers, and various remedies have been tried to solve the
problem.
One solution is the redeployment of doffers, and, to
a lesser extent, spinners, in different strategies which
would utilize the existing labor in the best way.
This thesis covers the development of a dynamic
simulation model of the spinner and doffer jobs. It will
enable comparisons to be made between various operating
strategies with emphasis on the doffing, piecing, and creeling
work.
Two models were developedl one model for a conventional
spinning room in which the doffers and spinners work independently;
the other model for a combination of the doffer
and spinner work into a single job.
The conventional spinning room model is a combination
of two basic routinesl a doffer routine and a spinner routine.
In operation the doffer routine simulates the doffing of
frames during a selected increment of time. For convenience
this time period was selected as the spinner cycle time.
At the end of each doffing time increment, the spinner routine simulates the piecing and creeling work at each side in the
assignment for one cyole. The simulation alternates between
the two routines until the desired simulation time is reached.
The model was validated against data from a Member
Mill, and several strategies were simulated and compared. A
doffing labor cost was determined for the main strategies
used.
One of the strategies simulated was the combination of doffer and spinner work into one job. This entailed the
development of a second model to simulate the combined work.
As part of this model, a method of generating piecing and
creeling occurrences per side was developed in which the
frequency of occurrences was related to the time elapsed
since the last service.
The computer programs of the two models are available
for use or adaptation by mills.
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