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Inspection - Coggle Diagram
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Function
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- Purchase Parts Inspection
- Work in Process Inspection
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- Design and Method Error Correction
- Finished Products Inspection
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Acceptance Sampling
Plans
Sampling
by Attributes
- Single Sampling: Sample inspected; lot accepted/rejected based on defect threshold.
- Double Sampling: Second sample allowed if first is inconclusive.
- Multiple Sampling: More than two samples possible until decision reached.
- Approach: Measure conformance degree.
- Advantages: Fewer inspections, diagnostic information.
- Disadvantages: Higher cost, complexity.
Sampling
by Variables
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- Frequency Distribution Based
- Disadvantages: ↑ inspection cost,
↑ Time cost, ↑ complex computations.
- Technique: Grading as defective or non-defective. Measures degree of conformance to specifications.
Points
- Purpose: Control product acceptability post-manufacture.
- Method: Random sample inspection.
- Decision Basis: Sample conformity to specifications. Define lot size, sample size, acceptance criteria.
Origins
- Inspection before/after a process based on standards.
- Decision-making tool for lot acceptability.
- Popularized by Dodge and Romig during World War II.
- Sample from a lot to decide on lot acceptance or rejection.
Uses
- Destructive testing scenarios.
- High cost or infeasibility of 100% inspection.
- When vendor quality is historically excellent.
Inspection
- Purpose: Ensure product standards Based on inspection standard.
- Role in Manufacturing: Quality control, defect prevention.
- Worker Skill Level: Varied; semi-skilled in mass production.
- Inspection Staff: Separate team for quality checks.
- Industry Reputation: Relies on product quality.
- Inspection Outcome: Does not create but controls quality.
- Frequency of Inspection: From 100% inspection to sampling.
- When to Inspect: At finished products, before costly processes, automatic machine outputs, irreversible operations.