| Summary: | This research is aimed to develop time-based guidelines that can help to preserve the
optical health of the visual inspectors at SanDisk Storage Malaysia (a WD company).
The research objectives is to identify the time patterns where defect escapees occur, to
analyse relationship between time and visual acuity and also to develop time based
guidelines for Visual Inspection operators. The method employed to analyse this is by
analysing a set of data retrieved from the system called Defect Escapee data. This data is
based on the number of drives inspected by first inspection station called VMI (Visual
Manual Inspection)3 but then detected as reject in the second inspection station; FQA
(Final Quality Assurance). Data analysis shows that there is a pattern between the time
that had lapsed in continuous visual inspection task and the occurrences of escapee from
VMI3 to FQA station. To confirm these findings two sets of controlled experiment was
conducted on which the visual inspectors were given 15 minutes break after every 1 hour
of inspection before they resume their visual inspection task. Another set, is where after
every 1.5 hours of visual inspection task, the visual inspectors were asked to swap duties
with mechanical assembly or manual related tasks before they return to their visual
inspection tasks after 1.5 hours. In conclusion, there is a correlation between continuous
inspection and defect detecting accuracy. The accuracy is inversely proportionate to time.
The longer the time spent in continuous visual inspection, the lesser the visual inspection
accuracy. This study is beneficial for organizations having visual inspection as part of
their process. The research results able to give insight to the process owners to develop
the most suitable work pattern for their employees stationed at Visual Inspection work
cells. (Abstratct by author)
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