Views: 0 Author: Site Editor Publish Time: 2025-04-23 Origin: Site
A CMM dimensional report is a structured document generated after measuring an injection-molded part using a Coordinate Measuring Machine. It includes:
Actual measurements of critical dimensions
Comparison with CAD/tolerance limits
Pass/Fail status for each feature
Graphical representations (e.g., color-coded deviation maps)
A typical CMM report in injection molding includes:
| Section | Description |
|---|---|
| Part Information | Part number, revision, material, and inspection date. |
| Measurement Plan | List of checked dimensions (e.g., diameters, angles, flatness). |
| Tolerance Comparison | Shows nominal value, measured value, and deviation. |
| Deviation Plot | Visual heatmap (e.g., red = out of tolerance, green = acceptable). |
| Summary & Conclusion | Overall pass/fail judgment and notes (e.g., "Hole Ø5.1mm exceeds max tolerance"). |
✔ Ensures Part Accuracy – Confirms dimensions match the CAD model.
✔ Detects Mold Wear – Identifies gradual deviations (e.g., cavity erosion).
✔ Supports PPAP/FAI – Required for First Article Inspection in automotive/aerospace.
✔ Reduces Scrap & Rework – Catches defects early before mass production.
Warpage (due to uneven cooling)
Sink Marks (from insufficient packing pressure)
Hole Misalignment (mold core shift)
Out-of-Tolerance Wall Thickness (flow imbalance)
| Feature | Nominal (mm) | Measured (mm) | Tolerance (±mm) | Status |
|---|---|---|---|---|
| Diameter (Ø10) | 10.00 | 10.05 | 0.1 | ✅ Pass |
| Wall Thickness | 2.00 | 1.88 | 0.15 | ❌ Fail |
| Flatness | 0.00 | 0.12 | 0.1 | ❌ Fail |
Conclusion: Wall thickness and flatness exceed tolerance; mold adjustment needed.
Define Critical Dimensions Early (GD&T callouts in design).
Use Statistical Process Control (SPC) to track trends over time.
Compare with Moldflow Analysis to predict warpage/shrinkage.
Archive Reports for Traceability (important for ISO/IATF audits).
CMM dimensional reports are essential for quality assurance in injection molding. By analyzing these reports, manufacturers can optimize injection molds, reduce defects, and ensure consistent part quality.
