| It was a 2 years issue
continually bother the engineers and buyers. |
| The symptom was that when
drove the screw into a blank hole (Fig 1), chippings
around the top of screwit were found (Fig 2), and it
is not acceptable by QC inspection. |
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Fig 1. Blank Hole |
Fig 2. Chippings |
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| The chippings were caused caused by askew screw
but why some screw works properly, and some not? |
| There were a couple of different screws that
were used in production (Fig 4), and all good screws
had the property of self-positioning. |
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 |
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Fig 3. Askew screw |
Fig 4. screws |
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People with local and international suppliers to solve 2-year-old issue |
| Further study fond that the "self-positioning
property" has nothing to do with the tip shape of
screw, but related the way of manufacturing process. |
| The conclusion is: |
| |
The screw supplier changed source |
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