FACTORS AFFECTING ACCURACY OF A MEASURING SYSTEM
The accuracy of an instrument depends on 5 basic elements (SWIPE)
- S- Standard
- W- Workpiece
- I- Instrument
- P= Person
- E- Environment
Normally the measuring instrument is calibrated with a standard are at regular interval. The
standard may be affected by
- Coefficient of thermal expansion
- Stability with time
- Elastic properties
- Geometric compatibility
- Position etc
2. Work piece:
The following factors affect the accuracy
- Cleanliness surface finish etc.
- Surface defects
- Hidden geometry
- Thermal equalization etc
The inherent characteristics of the instrument which affect the accuracy are
- Inadequate amplification
- Scale error
- Effect of friction backlash hysteresis etc
- Deformation while handling heavy w/p
- Calibration error
- Repeatability and readability
The factors responsible for accuracy are
- Training skill
- Sense of precision appreciation
- Ability to select measuring instrument & standard
- Attitude towards personal accuracy achievement
- Planning for measurement technique to have minimum just with consistent in precision.
The environmental factor are:
- Temperature press humidity
- Clean surrounding and minimum vibration
- Adequate illumination
- Temperature equalization between standard w/p and instrument
Higher accuracy can be achieved if all 5 factors are considered and steps are taken to eliminate them.
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