Injection Mold QC Inspection: CMM Measurement, First Article Check & Mold Pre-Shipment Inspection Workflow

Quality control is the backbone of every reliable injection mold. A well-executed QC workflow catches dimensional errors, surface defects and assembly issues before the injection mold leaves our factory, avoiding costly rework and production delays for mass molding. Our mold QC system covers three critical stages: CMM coordinate measurement, first article inspection (FAI), and mold pre-shipment inspection.

1. CMM Coordinate Measuring (3D CMM Inspection for Mold Cavity & Core)

CMM (Coordinate Measuring Machine) is used to verify the machined dimensions of mold core, cavity, inserts and critical mold features after CNC machining and polishing.

• We import the customer’s 3D STEP drawing into CMM software.

• The probe scans mold surfaces to measure critical dimensions, tolerances, hole positions, cavity depth and texture boundaries.

• Compare measured data against CAD nominal values, generate inspection reports with tolerance deviation.

• Key purpose: Confirm mold machining meets drawing tolerance before mold assembly.

Common check items: cavity size, wall thickness position, ejector pin hole, slider & angled lifter fit dimensions.

Note: For textured molds like vertical brushed grain on ABS appearance parts, we also check texture boundary and depth to guarantee uniform pattern after injection.

2. First Article Inspection (FAI / First Article Check, after T1 mold trial)

Once the injection mold assembly is finished, we run T1 test shot and perform First Article Inspection on the molded plastic sample, this is the most important QC step to validate the mold performance.

1. We take the first qualified molded part from injection trial.

2. Visual inspection: check surface marks, sink marks, weld lines, scratches, flow marks and texture uniformity.

3. Dimension inspection: Use calipers, micrometers and CMM to measure all critical part dimensions of the molded sample.

4. Material & appearance check: verify color, surface finish, texture, flash and burrs.

5. Record all data into FAI report, attach photos and measurement data.

6. Send the report + physical samples to customer for confirmation. Only after customer approves FAI report and samples, we proceed to fine-tune the injection mold for mass production.

3. Mold Pre-Shipment Inspection (Final QC before mold delivery)

Before packing and shipping the injection mold to customer, we carry out full mold pre-shipment inspection. Inspection checklist: ✅ Mold assembly: check mold opening/closing smoothness, slider, lifter, guide pin, locking structure movement. ✅ Cooling system: test water circuits for leakage. ✅ Ejection system: test ejector plate return and ejection action repeatedly. ✅ Surface check: cavity & core polishing, texture condition, no scratch or damage. ✅ Mold marking: mold number, cavity quantity, weight, lifting points. ✅ Mold spare parts: spare ejector pins, springs, O-rings, screws as agreed. ✅ Mold documentation: 2D drawings, BOM, maintenance manual, FAI report, CMM inspection report.

After passing all checks, we clean, apply anti-rust oil, wrap and pack the injection mold for shipment.

Why this 3-step QC workflow matters for your project

1. CMM catches machining errors early at mold making stage.

2. First Article Inspection proves that your final plastic part meets your drawing specs.

3. Final pre-shipment inspection ensures the whole injection mold works properly when it arrives at your factory.

Our QC team keeps all inspection records archived for future mold maintenance and repeat orders. If you have an upcoming injection mold project, send your CAD drawing for our DFM review and QC plan.