Polymers: Quality Control Systems: Tolerance
Design & Technology: AQA GCSE, topic 5.4.3
Tolerance in Quality Control Systems
In quality control systems, materials are cut, shaped, and formed to tolerances.
Cutting and shaping
- Materials can be cut to form parts.
- These parts need to be identical.
- Forming identical parts is not always possible.
- If we were to cut each material to size, there would be mistakes.
- This is why tolerances are introduced.
Tolerance
- Tolerance is the acceptable dimension that a piece of material can be.
- 1mm more or less than the specified measurement is usually tolerated.
- Tolerance does not allow for mismatched products to slip through the net.
- Tolerance allows products to be tested, checking if they meet quality standards.
Go / no-go systems
- A go / no-go system is a gauge that tests against the tolerances set for a part.
- The test can only be passed if you meet the 'go' requirement.
- The test can only be passed if you fail the 'no-go' requirement.
Example of go / no-go systems
- If a polymer rod fits the specified hole, it meets the 'go' requirement.
- If a polymer rod falls through the slightly larger hole, it fails the 'no-go' requirement.
- If either of the tests does not pass, the part needs to be redesigned or remanufactured.
- The part must fit within the tolerance boundaries.