Control Plan

When to Activate This Skill

• "Create a control plan for [part/process]"

• "What inspection frequency for [characteristic]?"

• "Define control methods for [operation]"

• "Link PFMEA to control plan"

• "What's the reaction plan for [out-of-spec condition]?"

• "Develop prototype/pre-launch/production control plan"

Control Plan Phases

Prototype Control Plan

• Purpose: Control during prototype build

• Focus: Dimensional measurements, material tests, performance

• Frequency: Often 100% on critical dimensions

• Duration: Until prototype approval

Pre-Launch Control Plan

• Purpose: Control during PPAP/validation runs

• Focus: Enhanced inspection, process validation

• Frequency: Increased sampling, SPC establishment

• Duration: Until production approval (PSW)

Production Control Plan

• Purpose: Ongoing production control

• Focus: Standardized controls, sustained quality

• Frequency: Based on process capability

• Duration: Life of production

AIAG Control Plan Format

Required Columns

Column Description Source

Part/Process Number Operation step number Process Flow

Process Name/Description Operation description Process Flow

Machine/Device/Jig/Tool Equipment used Process documentation

Characteristic Number Unique ID for characteristic Sequential

Product Characteristic Part feature being controlled Drawing, spec

Process Characteristic Process parameter affecting product PFMEA

Special Char Class CC, SC, or blank PFMEA/Drawing

Product/Process Spec Tolerance or requirement Drawing, spec

Evaluation/Measurement Gage/method used MSA

Sample Size Quantity inspected Based on risk

Sample Frequency How often inspection occurs Based on risk

Control Method How results are recorded/used SPC, checklist, etc.

Reaction Plan Action when out of spec Defined response

Special Characteristics

Critical Characteristics (CC)

• Symbol: Shield, (CC), or inverted delta

• Criteria: Safety or regulatory compliance

• Requirements:

• Documented in Control Plan

• Enhanced inspection (often 100%)

• SPC required (Cpk ≥1.67)

• Traceable records

• Identified on drawing

Significant Characteristics (SC)

• Symbol: Diamond, (SC)

• Criteria: Fit, function, appearance significant to customer

• Requirements:

• Documented in Control Plan

• Appropriate inspection frequency

• SPC recommended (Cpk ≥1.33)

• Records maintained

Standard Characteristics

• Symbol: None

• Criteria: All other characteristics

• Requirements:

• Documented in Control Plan

• Sampling based on risk

• Records as required

Sample Size and Frequency Guidelines

Based on Severity (from PFMEA)

Severity Sample Size Frequency Rationale

9-10 (Safety) 100% Every piece Safety critical - no escape

7-8 (High) 100% or n≥5 Per hour or per lot High customer impact

5-6 (Moderate) n≥3 Per shift or per setup Moderate risk

1-4 (Low) n≥1 Per lot or periodic Low risk

Based on Process Capability

Cpk Range Typical Frequency Notes

<1.00 100% or very frequent Process not capable

1.00-1.33 Every hour or more Marginal capability

1.33-1.67 Per shift or setup Capable

1.67 Per setup, daily, or lot Highly capable

Standard Frequency Terms

Term Meaning When to Use

Continuous 100% inspection Safety, high risk

Per piece Every part Critical characteristics

Per hour n pieces every hour SPC, high-risk

Per shift Start and end of shift Setup-sensitive

Per setup At setup only Stable characteristics

Per lot One sample per production lot Low-risk, stable

Daily Once per day Periodic verification

Weekly Once per week Very stable

Control Methods

Inspection Methods

Method Description Typical Use

Visual Operator observation Surface defects, presence

Go/No-Go Gage Attribute check Hole size, thread, profile

Caliper/Micrometer Variable measurement Dimensions

CMM Coordinate measurement Complex features

Height Gage Surface plate measurement Flatness, position

Profilometer Surface finish Ra, Rz

Hardness Tester Material property HRC, HRB

Torque Wrench Fastener torque Assembly

Leak Test Seal integrity Fluid systems

Functional Test Performance verification End-of-line

Recording Methods

Method Description When to Use

Check Sheet Attribute recording Visual checks, presence

Data Log Variable data recording Measurements

SPC Chart Statistical control chart Critical/significant

Traveler Part-specific record Traceability

Electronic MES/database entry High volume

None (process control) Poka-yoke, automated Error-proofed

Reaction Plans

Standard Reaction Plan Format

IF [out-of-spec condition] THEN:

1. STOP - Halt production/segregate suspect
2. CONTAIN - Quarantine affected parts
3. NOTIFY - Alert supervisor/quality
4. EVALUATE - Determine root cause and extent
5. CORRECT - Implement fix before restart
6. VERIFY - Confirm correction effective

Reaction Plan Examples

Dimension Out of Spec:

• Stop production

• Segregate last good part to current

• Notify Quality/Supervisor

• Check tool condition, offset, fixture

• Adjust/replace as needed

• Run first piece, verify to spec

• Inspect segregated parts 100%

Visual Defect:

• Reject defective part

• Assess severity (isolated vs trend)

• If trend: notify supervisor, review process

• Identify root cause (tool, material, handling)

• Implement correction

• Resume with enhanced attention

SPC Out of Control:

• Mark control chart

• Continue production if within spec

• Investigate pattern (rule violated)

• Identify assignable cause

• Implement correction

• Document on chart

PFMEA to Control Plan Linkage

Required Flow

PFMEA Item → Control Plan Entry ───────────────── ─────────────────── Process Step → Part/Process Number Function → Characteristic Failure Mode → What we're preventing Detection Control → Control Method S/O/D Ratings → Sample Size/Frequency Special Char → Special Char Class

Linkage Verification

For each Control Plan line, verify:

• PFMEA has corresponding failure mode

• Special characteristics match

• Control method addresses PFMEA detection

• Frequency appropriate for risk level

• Reaction plan defined

Output Format

When generating Control Plan content:

Control Plan

Part Number: [P/N] Part Name: [Description] Customer: [Customer Name] Control Plan Number: CP-[DEPT]-[SEQ] Phase: [ ] Prototype [ ] Pre-Launch [X] Production Revision: [Rev] | Date: [YYYY-MM-DD] PFMEA Reference: PFMEA-[XXX]

Operation: [Number] - [Name]

Characteristic 1: [Description]

Integration with Related Skills

PFMEA

Control Plan is direct output of PFMEA:

• Every PFMEA detection control → Control Plan method

• PFMEA severity drives inspection frequency

• PFMEA updates trigger Control Plan review

Load: read ~/.claude/skills/Pfmea/SKILL.md

MSA

All gages in Control Plan require MSA:

• Gage R&R for variable gages

• Attribute agreement for attribute gages

• MSA acceptance before production approval

Load: read ~/.claude/skills/Msa/SKILL.md

AutomotiveManufacturing

Work instructions must reflect Control Plan:

• Inspection steps in work instructions

• Operator-level control methods

• Quality checkpoints documented

Load: read ~/.claude/skills/Automotivemanufacturing/SKILL.md

Supplementary Resources

For detailed guidance: read ~/.claude/skills/Controlplan/CLAUDE.md

For templates: read ~/.claude/skills/Controlplan/templates/control-plan-template.md

For control method selection: read ~/.claude/skills/Controlplan/reference/control-methods.md

For sampling guidelines: read ~/.claude/skills/Controlplan/reference/sample-frequencies.md