dc.description.abstract |
Overall equipment effectiveness (OEE) is key equipment effectiveness measuring tool in
the implementation of total productive maintenance (TPM). Due to the limitations of
handling dynamic production loss, a deterministic method of handling OEE is not
recommended, because it doesn,t consider the dynamic nature of loss parameter that cause
to have daynamic result of OEE. Addtionaly, hidden losses are not investigated and
considerd well in deterministic method. As a result, the uncertainty method has been
introduced to reduce decision risk. Using the data collected during the production of 10-and 20-liter jerry cans, a study was conducted to investigate the effect of uncertain OEE at
the Amhara Golden pipe fitting technology company. Operator log sheets were used to
collect primary data for 45 days or 90 shifts to assess the blowing machine's OEE for both
products. The analysis has been conducted using four OEE models: model 1 with three
deterministic parameters, model 2 with three uncertain parameters, model 3 with five
deterministic parameters, and model 4 (proposed) with all five parameters being
uncertain. The availability, performance, quality, and OEE world-class evaluation are
90%, 95%, 99%, and 85%, respectively. Model 1's results in availability, performance,
quality and OEE are 78.84%, 66.84%, 97.45%, and 50.83% respectively for a 20L product.
Model 2 results are expressed as fuzzy numbers; availability (44.5%, 78%, 100%),
performance (44.5%, 78.6%, 100%), quality (97.7%, 98.2%, 98.7%), and OEE (19.3%,
60.3%, 98.3%) with a defuzzification value of 44.5%. Model 3 of availability, usability,
human factors, performance, and quality is 94.49%, 98.9%, 75.8%, 78.6%, 98.2%, and
54.6%, respectively. Model 4 yielded the following results: availability (89.8%, 92.3%,
94.2%), usability (72.4%, 98.3%, 98.5%), human factor (73.4%), 98.3%, 98.5%),
performance (44.9%, 78.6%, 100%), quality (98.1%, 98.2%, 98.3%), and OEE (21.1%,
61.3%, 89.8%) with a defuzzification value of 43.1%. The daily production variation for
the 26 days is (10.3%, 50.83%, and 86.84%). The closest models to the daily variation are
models 2 and 4 since the result is closer to the daily variation value. Model 4 is selected
for its additional importance, which is the visibility of loss. Finally, the uncertainty impact
would have been displayed if the planner and scheduler used this OEE result separately.
Key Words: TPM, OEE, Uncertain, Deterministic, Modified, Fuzzy Set, Defuzzification. |
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