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Control Chart Generator
Statistical Process Control & Quality Monitoring
Control Chart Generator
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Process Control Chart
Control Limits
UCL: 10.5492
Center Line: 10.1900
LCL: 9.8308
Std Dev: 0.1197
Process Status
Status:High Variation
Out of Control: 0 points
Trending: 0 points
Data Summary
Sample Size: 10
Range: 0.4000
Mean: 10.1900 mm
Control Chart Rules & Interpretation
Out of Control Signals:
- Any point beyond control limits (±3σ)
- 7+ consecutive points on one side of center line
- 2+ consecutive points beyond warning limits (±2σ)
- Unusual patterns or trends
Process Capability:
- Cpk ≥ 1.33: Excellent capability
- Cpk ≥ 1.0: Adequate capability
- Cpk < 1.0: Poor capability
- Cp: Potential capability (centered process)
📊 About Control Charts
Control charts are statistical tools used to monitor process performance over time and detect when a process goes "out of control."
Key Components
- • Center Line (CL) - Process average
- • Upper Control Limit (UCL) - +3σ
- • Lower Control Limit (LCL) - -3σ
- • Warning limits at ±2σ
Applications
- • Manufacturing quality control
- • Service process monitoring
- • Healthcare performance tracking
- • Financial process control
🎯 Control Chart Types
Variable Data Charts
- • X̄-R Chart: Sample average and range
- • X̄-S Chart: Sample average and standard deviation
- • I-MR Chart: Individual values and moving range
Attribute Data Charts
- • p-Chart: Proportion defective
- • np-Chart: Number defective
- • c-Chart: Count of defects
- • u-Chart: Defects per unit
🏭 Practical Example
Scenario: Automotive Parts Manufacturing
A manufacturer produces engine pistons with a target diameter of 85.00mm ± 0.10mm. Quality control measures 5 pistons every hour:
Process Monitoring:
- • Sample size: 5 pistons per subgroup
- • Frequency: Every hour (24 subgroups/day)
- • Chart type: X̄-R Chart for continuous monitoring
- • Specification limits: 84.90 - 85.10mm
Results Analysis:
- • Process average: 85.02mm (slightly high)
- • Process variation: ±0.03mm (excellent control)
- • Cpk = 1.67 (process very capable)
- • Action: Minor adjustment to center process
⚠️ Out of Control Signals
Pattern Recognition
- • Rule 1: Any point beyond ±3σ limits
- • Rule 2: 9+ consecutive points on one side
- • Rule 3: 6+ consecutive increasing/decreasing
- • Rule 4: 14+ alternating up and down
- • Rule 5: 2/3 consecutive beyond ±2σ
Corrective Actions
- • Investigate: Find root cause immediately
- • Adjust: Make process corrections
- • Document: Record actions taken
- • Monitor: Verify improvement
- • Prevent: Implement preventive measures