1. Basic Quality Control Philosophy
Quality control for precision parts is not just "gatekeeping" at final inspection — it is "prevention" throughout the entire manufacturing process. An effective QC system follows these principles:
- Prevention first: Through process control and in-process inspection, detect and eliminate hazards before defects occur
- Everyone participates: Quality is everyone's responsibility — operators, inspectors, engineers, managers
- Data-driven: Speak with measurement data, use statistical analysis (SPC) to find trends and anomalies
- Traceability: Every batch records material source, machining process, inspection results, operators
2. Incoming Quality Control (IQC)
Purpose
Ensure purchased raw materials, outsourced parts, and standard parts meet drawing and technical requirements, preventing non-conforming materials from entering production.
Inspection Content
- Material verification: Check mill certificates for grade, chemical composition, mechanical properties; perform PMI (Positive Material Identification) via spectral analysis when needed
- Dimensional inspection: Bar stock diameter, length, straightness, roundness; sheet thickness, flatness; tube OD, wall thickness, ovality
- Surface quality: Check for cracks, scratches, oxide scale, rust, inclusions
- Quantity and identification: Verify quantity, check material identification is clear and traceable