Quality managementReading time 12 min
From Drawing to Inspection Report
An inspection report must show what was checked, how it was measured and whether it passed. Follow the path from ballooned drawing to recorded results, including first-article and sampling decisions.
01Balloon the drawing
Ballooning assigns a unique number to each drawing requirement that must be inspected. The same number appears on the report beside the measured result. This simple link lets a reviewer trace every value back to the exact location and callout on the drawing.
What gets a number
- Every toleranced dimension, whether individually called out or covered by the general tolerance.
- Every feature control frame, together with its datums.
- Every surface finish symbol, including the global default near the title block.
- Notes covering material, heat treatment and surface treatment.
- Thread specifications, deburring requirements, marking and packaging requirements.
02First-article forms
AS9102 organizes aerospace first-article inspection into three forms covering the part, materials and processes, and product characteristics. Other industries may use a similar structure, but their customer requirements still govern.
| Form | Contents | The question it answers |
|---|---|---|
| Form 1 | Part identity, drawing number, revision, part number | Which revision of which part is this |
| Form 2 | Evidence for material, special processes and functional tests | Is there proof behind the material and the processes |
| Form 3 | Measured result and verdict for every specification | What did each dimension actually measure |
What one row of Form 3 needs
| Field | Contents | Common mistake |
|---|---|---|
| Balloon number | Matches the number on the drawing | Numbering does not match the drawing |
| Specification | Nominal and deviations from the drawing | Nominal only, no tolerance |
| Measured value | The number actually obtained | Writing “OK” instead of a value |
| Instrument | Which gauge, and its identification number | Left blank, so nothing is traceable |
| Verdict | Pass or fail | Borderline values not rounded to a stated rule |
| Notes | Concession, rework, measurement conditions | Empty |
03Planning the sample size
Sampling answers two separate questions: how many units to inspect and what acceptance rule to apply. A standard such as ISO 2859-1 provides plans for attribute inspection; choose the plan to match the agreed quality level and inspection conditions.
| Batch | Code letter, general inspection level II | Sample size | Ac / Re at AQL 1.0 |
|---|---|---|---|
| 51 ～ 90 | E | 13 | 0 / 1 |
| 91 ～ 150 | F | 20 | 0 / 1 |
| 151 ～ 280 | G | 32 | 1 / 2 |
| 281 ～ 500 | H | 50 | 1 / 2 |
| 501 ～ 1200 | J | 80 | 2 / 3 |
A sampling plan manages acceptance risk; it does not prove every shipped unit is defect-free. Critical characteristics may need a stricter plan or complete inspection, depending on the customer and the risk.
04From results to capability
Keep the measured values, not only pass/fail. Actual results reveal trends, centering and drift that a binary verdict hides, and provide data for later capability analysis.
| Metric | Concept | What it looks at |
|---|---|---|
| Cp | Tolerance band ÷ 6σ | Whether the spread is small enough |
| Cpk | Also accounts for the mean being off centre | Whether it leans to one side |
| Pp / Ppk | Calculated from long-term overall variation | Real performance including between-lot variation |
Cpk targets vary by customer and characteristic. Before comparing any result with a target, check that the process is stable and the measurement system is suitable; a calculated index alone is not evidence of control.