Procescapabiliteitsindex (Cp/Cpk) is een begrip binnen de industriële digitalisering en kwaliteitsmanagement & software.
Definitie
Procescapabiliteitsindex (Cp/Cpk) zijn statistische maatstaven die de capability van een manufacturing process meten om producten binnen gespecificeerde toleranties te produceren. Cp meet process potential capability, terwijl Cpk de actual capability meet rekening houdend met process centering ten opzichte van het target value.
Kenmerken
- Cp calculation: Process spread vergeleken met specification tolerance (USL-LSL/6σ)
- Cpk calculation: Process capability adjusted voor centering, minimum van Cpu en Cpl
- Process stability: Requires statistical process control voordat capability assessment
- Normal distribution: Assumes process data follows normal statistical distribution
- Short-term capability: Typically calculated over limited time periods (25-100 samples)
- Specification limits: Requires clearly defined upper en lower specification limits
- Statistical significance: Minimum sample sizes voor reliable capability estimates
- Continuous monitoring: Regular recalculation als process conditions change
- Benchmarking standards: Industry-accepted minimum Cp/Cpk values voor different applications
Toepassing
Machining process capability:
- Turning operations: Diameter, length, surface finish capability studies
- Milling processes: Dimensional accuracy, surface quality capability assessment
- Grinding operations: Precision grinding capability voor tight tolerances
- CNC process validation: Machine capability verification voor new setups
Welding process capability:
- Weld penetration: Depth en consistency capability studies
- Weld bead geometry: Width, height, profile capability assessment
- Mechanical properties: Tensile strength, hardness capability evaluation
- Non-destructive testing: X-ray, ultrasonic test result capability
Quality control applications:
- SPC implementation: Process capability as basis voor control charts
- Incoming inspection: Supplier process capability verification
- Process qualification: New process approval based on capability studies
- Quality improvement: Capability tracking voor process optimization
Supplier assessment:
- Vendor qualification: Supplier process capability requirements
- Quality agreements: Minimum Cp/Cpk values in supplier contracts
- Process audits: Capability verification during supplier evaluations
- ISO compliance: Process capability as quality system requirement
Production planning:
- Process selection: Choosing manufacturing methods based on capability requirements
- Tolerance allocation: Design tolerance assignment based on process capability
- Capacity planning: Production volume decisions considering process capability
- Cost optimization: Balancing process capability met manufacturing costs
Gerelateerde begrippen
Verwante termen:
- SPC - Process control methodology using capability indices
- Quality analysis - Data analysis tools voor capability calculation
- Control plan - Quality planning document including capability requirements
- Process validation - Manufacturing process qualification using capability studies
Verwante concepten:
- Six Sigma - Quality improvement methodology emphasizing process capability
- Lean - Efficiency methodology complemented by capability improvement
- MSA - Measurement reliability assessment prerequisite for capability
- DFM - Product design considering manufacturing process capabilities
Bronnen
- AIAG (Automotive Industry Action Group) - SPC manual en capability guidelines
- ISO/TS 16949 - Automotive quality standard including capability requirements
- ASQ (American Society for Quality) - Process capability training en certification
- NIST Engineering Statistics Handbook - Statistical methods voor capability analysis
- Minitab Statistical Software - Capability analysis tools en procedures
- JMP Statistical Software - Process capability calculation en visualization
- Montgomery Design en Analysis of Experiments - Statistical process control textbook
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