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Abstract:
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Machine reliability and flag maintenance effectiveness are two factors that can affect
the productivity of a weaving operation. Benchmarking is a tool to aid in achieving World
Class performance by seeking out and applying the best practices of other organizations. A
benchmark is a standard or set of standards by which an organization can be compared.
A key measure of flag maintenance effectiveness is the percent fITst time repair
success of the technicians working on the equipment. An effective flag maintenance program
analyzes repetitive failures and finds ways to prevent them from recurring.
Reliability is the probability that for a specified time an item will perform its intended
function without failure. Failure rate is expressed in terms of failure per unit time. Mean
time between failure (MTBF) is the reciprocal of the failure rate. MTBF is the average time
that a machine is expected to run between failure.
The purpose of this thesis was to establish benchmarks for machine reliability and flag
maintenance effectiveness in projectile weaving operations. Projectile weaving was chosen
because the age of the equipment in the industry and the mechanical nature of the weft
insertion mechanism facilitated the collection of flag data. The methodology used to
benchmark machine reliability and flag maintenance effectiveness, however, can be applied
to other types of weaving equipment.
The Weave ITT computer software was used to index the weaveability of the fabric
styles in each plant in the study because fabric styling can affect the MTBF of a weave plant.
Since the age of the weaving equipment can also affect the MTBF of a weave plant,
benchmarks were established for Sulzer PU and Sulzer TW -11 machines because these machines are in the same general age group.
The benchmark for flag maintenance effectiveness was established from the plant with
the highest first time repair success. The benchmark for flag maintenance effectiveness is
92.0 percent first time repair success.
The benchmarks for MTBF were established by determining the flags per 100
machine hours for each of the fourteen categories of flag failure used in this study for each
machine type. The benchmark MTBF for Sulzer PU machines and Sulzer TW-ll machines
were determined from this data at various Weave ITT indices.
A method was also established to determine the machine production hours that can be
gained by reaching the benchmarks for flag maintenance effectiveness and MTBF. The gain
in machine production varies from plant to plant depending on their current performance.
The decision to pursue these benchmarks ultimately rest with the management of the weaving
operations.
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