These sources of variation effect every process to some extent or another!
Variation created by man or people:
- Inconsistency from one person to another person
- Differences in abilities, skills, motivation, attitude, etc.
Variation created by machines or equipment:
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Variation from one machine to another
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Differences in machine or equipment capability as it ages or wears
Variation created by material:
- Inconsistency from one lot of material to another
- Differences in suppliers of the same part number
Variation created by method:
- Failure to have a documented method
- Differences from one person to another person following the same method
Variation created by mother nature:
- Inconsistency from one day to the next
- Seasonal differences
Variation created by measurement:
- Inconsistency from one person to another person
- Inconsistency within the same person
- Differences between how you measure something and how your customer measures it