Process Step is a work item type that represents a discrete manufacturing or assembly operation within a production workflow. Process Steps form the Level 1 (top level) of the Process FMEA (PFMEA) hierarchy, where failure modes and their root causes are analyzed to ensure product quality and process reliability in automotive manufacturing environments.
Process Steps are central to IATF 16949/APQP (Advanced Product Quality Planning) workflows and serve as parent entities for Process Failure Modes and Control Plan Items. They provide the structural foundation for documenting manufacturing processes, identifying failure points, implementing detection and prevention controls, and maintaining traceability to system elements and equipment.
Overview and Purpose
In TestAuto2 — Automotive Safety Solution, Process Steps enable:
- Process FMEA Analysis: Structure the manufacturing workflow to systematically identify what can go wrong at each production stage
- Control Plan Development: Link manufacturing processes to quality characteristics and inspection methods
- Equipment Traceability: Connect process steps to the production equipment (system elements) that execute them
- Failure Mode Analysis: Serve as the parent entity for Process Failure Modes (Level 2 in the PFMEA hierarchy)
- ISO 26262 & IATF Integration: Support functional safety requirements by documenting process controls and their effectiveness
A typical example: “Solder Wave Process for Circuit Board Assembly” or “Sensor Housing Injection Molding” are Process Steps that organize manufacturing operations.
Core Properties
| Name | Type | Default | Description |
|---|
id | String | Auto-generated | Unique identifier for the process step (e.g., PS-001, PS-Solder-Wave) |
title | String | Required | Human-readable name of the manufacturing process step (e.g., “Wave Soldering - PCB Assembly”) |
description | String | Empty | Detailed description of the process step, including inputs, outputs, and key parameters |
status | Enum | draft | Workflow status tracking process maturity (values: draft, inProgress, inReview, pendingApproval, approved, rejected, obsolete) |
assignedTo | User | Unassigned | Engineer or process owner responsible for defining and maintaining the process step documentation |
priority | Enum | normal | Priority level for process improvement actions (values: low, normal, high, critical) |
category | String | Empty | Process category classification (e.g., “Assembly”, “Molding”, “Testing”, “Soldering”) |
Relationship Fields
| Name | Link Role | Target Type | Cardinality | Description |
|---|
processFMEAs | assesses | Process Failure Mode | 0..* | Outgoing link: Process Failure Modes analyzed for this process step |
controlPlanItems | monitorsThrough | Control Plan Item | 0..* | Outgoing link: Quality characteristics and inspection methods that control this process |
systemElements | involves | System Element | 0..* | Outgoing link: Production equipment, tooling, or manufacturing resources used in this step |
processFlow | partOf | Process Flow Document | 0..1 | Outgoing link: Parent process flow document that sequences this step |
relatedProcessSteps | precedesIn / followsIn | Process Step | 0..* | Bidirectional links: Process sequence and dependencies (e.g., Wave Soldering precedes Rework Soldering) |
PFMEA Hierarchy Structure
Process Steps occupy Level 1 of the three-level PFMEA hierarchy:
When you drill down into a Process Step row in the PFMEA Risksheet, you see all associated Failure Modes (Level 2). Each Failure Mode can have multiple root causes (Level 3), each with its own occurrence, detection, and RPN values. Metrics roll up from Level 3 → Level 2 → Level 1.
Custom Fields for Process Analysis
| Field Name | Type | Enumeration | Description |
|---|
processCategory | Enum | Process categories defined in project config | Classification of process type (e.g., “Assembly”, “Welding”, “Coating”, “Testing”) |
processOwner | User | — | Person responsible for process execution and control maintenance |
standardOperatingProcedure | Text | — | Reference to or inline documentation of the SOP governing this process |
equipmentId | String | — | Manufacturing equipment ID or asset tag (cross-reference to system element) |
cycleTime | Float | — | Nominal cycle time in seconds or minutes for this process step |
yield | Float | — | Typical first-pass yield percentage for this process (baseline for PFMEA severity assignment) |
controlMethodology | Enum | SPC, 100%_Inspection, Sampling, Visual, Automated | Quality control approach used to verify process conformance |
effectivenessMetric | Float | — | Process control effectiveness rating (pre- and post-mitigation) as input to PFMEA detection ratings |
SC/CC and Control Plan Integration
Process Steps connect to Control Plan Items via the monitorsThrough link role. When a Control Plan Item is marked as a Special Characteristic (SC) or Critical Characteristic (CC), it indicates that:
- SC (Special Characteristic) — This process parameter significantly affects product function or safety and requires documented control plan procedures
- CC (Critical Characteristic) — This process parameter is critical to safety (per ISO 26262) and requires enhanced control, measurement, and reaction planning
The TestAuto2 Control Plan Risksheet displays Process Steps at Level 1, with associated Characteristics and Control Methods nested below, showing which quality attributes are monitored at each production stage.
A single Process Step may have multiple Control Plan Items. For example, “Wave Soldering” might have control plan items for:
- Solder temperature (process characteristic)
- Joint quality (product characteristic)
- Flux coverage (process characteristic)
- Lead-free solder composition (material characteristic)
Workflow State Transitions
Process Steps follow the standard seven-state lifecycle workflow:
| From State | To State | Condition | Auto-Action |
|---|
draft | inProgress | Assignee set | — |
draft / inProgress | inReview | Peer review requested | Clear approvals |
inReview | inProgress | Rework requested | — |
inReview | pendingApproval | Approval requested | — |
pendingApproval | approved | All required signatures collected | Mark approvals as final |
approved / inReview / pendingApproval | rejected | Rejected by approver | Clear approvals; revert to draft |
| Any | obsolete | Process step superseded or retired | Mark superseded entity reference |
Process Steps should not enter approved state until the associated PFMEA analysis is complete and risk controls (prevention and detection methods) are defined. This ensures traceability between process definition and quality controls.
Relationship to ISO 26262 and IATF 16949
ISO 26262 Integration
Process Steps support ISO 26262-4 (System Design) and Part 9 (Functional Safety Assessment) by:
- Documenting manufacturing processes that could introduce systematic failures (e.g., solder defects affecting electrical safety)
- Linking to System Elements (production equipment) to ensure equipment reliability
- Connecting to Process Failure Modes that chain upstream to Design Failure Modes and System Requirements
- Enabling closed-loop traceability: Hazard → Safety Goal → System Requirement → Design → Process Failure Analysis
IATF 16949/APQP Alignment
Process Steps are core to APQP (Advanced Product Quality Planning):
- Phase 1 (Plan & Program Definition): Define manufacturing process steps and operational flow
- Phase 2 (Product Design & Development Verification): Link design characteristics to process steps via Control Plan Items
- Phase 3 (Process Design & Development Verification): Execute PFMEA analysis; assign occurrence/detection ratings based on process control effectiveness
- Phase 4 (Product & Process Validation): Monitor Control Plan Item measurements to validate process capability
- Phase 5 (Feedback, Assessment & Corrective Action): Drive continuous improvement through PFMEA updates and control plan refinement
Linking to Other Work Item Types
Upstream Links (Process Definition)
| Target Type | Link Role | Purpose |
|---|
| Process Flow | partOf | Parent process flow diagram; defines sequence and dependencies |
| System Element | involves | Production equipment, tooling, fixtures, or manufacturing resources |
| Work Instructions | references | External SOP, drawing, or procedural documentation |
Downstream Links (Process Analysis & Control)
| Target Type | Link Role | Purpose |
|---|
| Process Failure Mode | assesses | PFMEA row (Level 2); what can go wrong at this step |
| Control Plan Item | monitorsThrough | Quality characteristic or inspection method that controls this step |
| Risk Control | controlledBy | Mitigation action that reduces PFMEA severity, occurrence, or detection |
PowerSheet Integration: Process Steps Sheet
The Process Steps Sheet PowerSheet provides a two-section view:
- Left Section (Process Steps): ID, Title, Description, Category, Owner, Cycle Time, Yield
- Right Section (System Elements): Linked equipment and manufacturing resources via
systemElements relationship
# Process Steps Sheet - Simplified Structure
source:
entityType: ProcessStep
columnGroups:
- name: "Process Steps"
columns:
- id [collapsed focus]
- title [bold ascending sort]
- description
- category
- processOwner
- cycleTime
- yield
- name: "Equipment Involved"
expansion:
relationship: systemElements
columns:
- id
- title
- equipmentType
- Verify all process steps are documented and assigned
- Trace equipment involvement across the production workflow
- Ensure process steps are linked to correct System Elements (no orphaned steps or equipment)
Risksheet Column Integration: PFMEA Level 1
Process Steps appear as Level 1 rows in the Process FMEA Risksheet:
| Column Group | Columns | Notes |
|---|
| Process Identification | Process Step ID, Title, Description, Category | Level 1 row headers; collapsible to title |
| Failure Modes | FM Count, Associated Failure Modes | Drill-down to Level 2 |
| Controls & Status | Prevention Controls Summary, Detection Controls Summary | Aggregate from Level 2-3 |
| RPN / Action Priority | RPN Range, Highest AP (H/M/L) | Aggregated metrics |
| Equipment | Linked System Elements | Quick reference to production resources |
- Level 2 (Failure Modes) appear indented below, showing what can go wrong
- Each Failure Mode (Level 2) can be further expanded to show Level 3 root causes
- Individual cause rows show Severity, Occurrence, Detection, RPN, and pre/post-mitigation values
- Control methods (prevention and detection) are documented per cause
Example: Sensor Housing Injection Molding Process
PS-003: Injection Molding - Sensor Housing Assembly
| Property | Value |
|---|
| Status | Approved |
| Owner | Manufacturing Engineer (Bob Smith) |
| Equipment | Injection Molding Machine XYZ-2000 |
| Cycle Time | 45 seconds |
| Yield | 96.5% |
- CP-001: Mold Temperature (Process Char) — Target: 85+/-5 C
- CP-002: Injection Pressure (Process Char) — Target: 1200+/-50 bar
- CP-003: Wall Thickness (Product Char - SC) — Target: 2.5+/-0.2 mm
- CP-004: Surface Finish (Product Char) — Target: Ra 1.6 um max
PFMEA Failure Modes (assesses):
- FM-1: Incomplete Fill (short shot) — O:4, D:5, AP:H
- FM-2: Surface Voids/Porosity — O:3, D:3, AP:H
- FM-3: Flash at Parting Line — O:2, D:2, AP:M
- FM-4: Warping/Dimensional Variation — O:5, D:4, AP:H
System Elements (involves):
- Injection Molding Machine XYZ-2000
- Mold Cavity Assembly
- Hopper & Drying System
Creating and Managing Process Steps
Typical Workflow
- Define — Create a Process Step work item with title, description, and process category
- Assign Ownership — Set
processOwner and assignedTo fields
- Link Equipment — Use
systemElements relationship to link to production equipment
- Execute PFMEA — Create Process Failure Modes (Level 2) linked via
assesses relationship
- Define Controls — Link Control Plan Items via
monitorsThrough relationship
- Approve — Route through review/approval workflow; transition to
approved state
- Monitor — Track Control Plan Item measurements and update effectiveness ratings
Best Practices
Each Process Step should represent one distinct manufacturing operation. Avoid combining multiple operations into a single step (e.g., separate “Soldering” from “Rework Soldering” or “Inspection”). Finer granularity enables more precise failure mode identification.
Always link Process Steps to the actual production equipment (System Elements). This enables supply chain risk assessment (e.g., “Which processes depend on Equipment X?”) and supports production audit trails.
All Control Plan Items linked to a Process Step must have defined Target Values, Tolerances, and Reaction Plans before the Process Step is approved. Missing or incomplete control specifications can delay quality certification.
References
For related documentation, see:
