Overview
Process Failure Modes operate within a three-level PFMEA hierarchy:
Each process failure mode is assessed using AIAG-VDA FMEA methodology with pre-mitigation and post-mitigation severity, occurrence, and detection ratings. The combination of these three ratings produces an Action Priority (AP) score that drives control implementation prioritization.
Core Properties
| Name | Type | Default | Description |
|---|
| ID | String | Auto-generated | Unique identifier for the process failure mode work item (e.g., PFM-001). Assigned by Polarion outline numbering system within the PFMEA document hierarchy. |
| Title | String | Required | Concise description of the failure mode (e.g., “Inadequate torque application during fastening”). Must be specific to the process failure scenario, not generic. |
| Description | String | Optional | Extended narrative describing the failure mode in detail. Captured in Level 2 of the risksheet hierarchy and serves as the collapseTo target for aggregating causes. |
| Status | Enumeration | Draft | Workflow state of the process failure mode. Values: Draft, In Progress, In Review, Approved, Closed. Tracks completion through PFMEA lifecycle. |
| Assignee | User | Unassigned | Team member responsible for mitigation planning and control verification for this failure mode. |
| Priority | Enumeration | Medium | Internal priority for action assignment independent of Action Priority calculation. Values: Low, Medium, High. |
| Module | Link (riskSpecification) | — | Parent PFMEA document containing this failure mode. Auto-populated when creating failure modes in Risksheet context. Required for document-level RPN aggregation in reports. |
FMEA Assessment Properties
Process FMEA uses a three-part assessment framework: Severity (S), Occurrence (O), and Detection (D). Each component has pre-mitigation and post-mitigation ratings.
Severity Rating
| Name | Type | Default | Description |
|---|
| pfmSeverity | Enumeration (1-10) | 0 | Severity rating of the effect of the failure mode — how serious the consequence is if the failure occurs. Scale 1 (minimal impact) to 10 (catastrophic impact, safety-critical). Severity typically does NOT change between pre- and post-mitigation because it reflects the inherent impact of the failure, not control effectiveness. |
- 1 — Negligible: No effect on performance or customer satisfaction
- 2–3 — Minor: Slight performance degradation, customer may notice
- 4–5 — Moderate: Significant performance loss, safety not impacted
- 6–7 — High: Major performance loss or minor safety concern
- 8–9 — Severe: Significant safety concern or system inoperability
- 10 — Catastrophic: Potential safety hazard or vehicle failure
Occurrence Ratings (Before and After Mitigation)
| Name | Type | Default | Description |
|---|
| premitigationPFMOccurrence | Enumeration (1-10) | 0 | Likelihood rating of how frequently the cause occurs given CURRENT process controls, before implementing additional mitigation. Scale 1 (remote) to 10 (very high). Used in pre-mitigation RPN calculation. |
| postmitigationPFMOccurrence | Enumeration (1-10) | 0 | Likelihood rating of how frequently the cause occurs AFTER implementing process control improvements (prevention controls). Demonstrates risk reduction from prevention control implementation. Used in post-mitigation RPN calculation. |
- 1 — Remote: <1 in 1,000,000 parts
- 2 — Very Low: 1 in 500,000 parts
- 3 — Low: 1 in 100,000 parts
- 4–5 — Moderate: 1 in 10,000 to 1 in 5,000 parts
- 6–7 — High: 1 in 1,000 to 1 in 500 parts
- 8–9 — Very High: 1 in 100 to 1 in 50 parts
- 10 — Extremely High: >1 in 50 parts (more than 20,000 per million)
Detection Ratings (Before and After Mitigation)
| Name | Type | Default | Description |
|---|
| premitigationPFMDetection | Enumeration (1-10) | 0 | Effectiveness rating of current process controls at DETECTING the failure mode before it reaches the customer, before implementing additional detection controls. Scale 1 (certain detection) to 10 (no detection). Used in pre-mitigation RPN calculation. Inverted scale: higher = worse. |
| postmitigationPFMDetection | Enumeration (1-10) | 0 | Effectiveness rating of process controls at DETECTING the failure mode AFTER implementing additional detection mechanisms (gauges, tests, inspections). Demonstrates detection improvement. Used in post-mitigation RPN calculation. |
- 1 — Certain: Current controls 100% detect failure before escape
- 2 — Very Low: >99% detection likelihood
- 3 — Low: 95-99% detection likelihood
- 4–5 — Moderate: 80-95% detection likelihood
- 6–7 — High: 50-80% detection likelihood
- 8–9 — Very High: 10-50% detection likelihood
- 10 — Extremely High: <10% detection likelihood (near certain escape)
Action Priority and RPN Calculation
| Name | Type | Default | Description |
|---|
| premitigationPFMAP | Enumeration (H/M/L) | Unrated | Action Priority rating BEFORE implementing risk controls, derived from Severity × Occurrence × Detection using AIAG-VDA FMEA-4 classification thresholds. Guides prioritization of mitigation resource allocation. Typically calculated via Risksheet formula. Values: High, Medium, Low. |
| postmitigationPFMAP | Enumeration (H/M/L) | Unrated | Action Priority rating AFTER implementing process controls, demonstrating risk reduction effectiveness. Guides decisions on whether controls are adequate or further mitigation is needed. Required for PFMEA completion. |
| pfmRPN | Integer | 0 | Pre-mitigation Risk Priority Number calculated as Severity × Occurrence × Detection. Used for initial prioritization and threshold-based alerts. Typical thresholds: 1–40 (Low), 41–100 (Medium), >100 (High/unacceptable). |
| pfmRPNPost | Integer | 0 | Post-mitigation RPN showing residual process risk after control implementation. Demonstrates mitigation effectiveness. Must be ≤ pre-mitigation RPN; ideally below action threshold (typically 40–100 depending on industry). |
AIAG-VDA FMEA standards recommend: 1–40 (acceptable), 41–100 (monitor/plan controls), >100 (unacceptable, immediate action required). Thresholds are customizable per organizational risk appetite.
Description Fields
| Name | Type | Default | Description |
|---|
| effectOfFailure | String (free-text) | Undetermined | Describes the customer-visible or downstream consequence if the failure mode occurs (e.g., “Product dimensions out of specification, customer rejection”). Used to determine severity rating. Distinct from Cause (why failure happens) and Failure Mode (how failure manifests). |
| causeOfFailure | String (free-text) | Undetermined | Free-text description of the root cause enabling the failure mode (e.g., “Wrench calibration drift causing torque variation”). Appears in Level 3 of the risksheet. Multiple causes can exist per failure mode, each with separate O/D ratings. Used to design prevention controls. |
Effect = WHAT happens when failure occurs (consequence)
Cause = WHY failure occurs (root reason)
Failure Mode = HOW failure manifests (the state or behavior)
Conflating these leads to weak mitigation targeting the wrong level.
Process Control Fields
| Name | Type | Default | Description |
|---|
| preventionControl | String (free-text) | — | Description of process controls that PREVENT the cause from occurring (e.g., “Torque wrench calibration procedure every 500 uses”). Prevention controls target root causes and lower occurrence ratings. Examples: procedure changes, tool calibration, training, equipment upgrades. Justifies occurrence ratings. |
| detectionControl | String (free-text) | — | Description of process controls that DETECT the failure before it reaches the customer (e.g., “100% final dimension gauge check”). Detection controls do not prevent failure but catch it. Examples: in-process inspections, gauging, visual checks, test runs. Justifies detection ratings. |
Safety Classification
| Name | Type | Default | Description |
|---|
| scccClassification | Enumeration | Unclassified | Safety classification for characteristics linked to this failure mode: SC (Safety Critical) or CC (Critical Characteristic). SC items require stricter verification and control per IATF 16949. Rendered as orange badge (SC) or red badge (CC) in PowerSheet views. |
SC (Safety Critical): Failure affects vehicle safety or compliance with safety standards. Requires enhanced controls and verification.
CC (Critical Characteristic): Failure affects product function, performance, or customer satisfaction but not safety. Standard controls apply.
Relationships and Links
| Link Role | Target Type | Cardinality | Description |
|---|
| assesses | processStep | Many-to-One | Links the process failure mode to the parent Process Step being analyzed. Each Level 2 failure mode assesses exactly one process step. Established in Risksheet Level 1→2 hierarchy via itemLink. |
| assessedBy | cause | Many-to-Many | Inverse relationship: Level 3 causes that contribute to this failure mode. Each cause can be assessed by multiple failure modes. Enables multi-cause analysis per failure mode. |
| mitigatedBy | riskControl | Many-to-Many | Links to Risk Control work items that reduce occurrence or detection risk for this failure mode. Enables traceability from failure mode to implementation (e.g., procedure change, new equipment). |
| linkedTo (characteristic) | characteristic | Many-to-Many | Optional links to Characteristic work items for characteristics affected by this failure mode. Enables traceability from characteristics to process risks. |
Workflow Lifecycle
Process Failure Modes follow a standard FMEA workflow with 5 states:
| State | Meaning | Typical Actions |
|---|
| Draft | Initial creation, not yet formally analyzed | Add description, identify causes, estimate initial ratings |
| In Progress | Being actively analyzed and assessed | Finalize S/O/D ratings, design controls, calculate AP |
| In Review | Complete, awaiting peer review and approval | Review team assesses adequacy of controls; provides feedback |
| Approved | Reviewed and accepted; controls approved for implementation | Engineering team implements controls; tracks completion |
| Closed | Mitigation completed and verified; no further action | Document post-mitigation evidence; compare pre vs post ratings |
Three-Level Risksheet Hierarchy
The Process Failure Mode appears as Level 2 in the standard PFMEA risksheet structure:
Level 1: Process Step
├─ Process Step ID: PS-001
├─ Process Step Title: "Fastening - Sensor Housing"
│
└─ Level 2: Process Failure Mode
├─ Failure Mode: "Inadequate torque"
├─ Effect: "Housing loose, sensor alignment failure"
├─ Severity: 8
├─ Occurrence: 4 (before) → 2 (after prevention)
├─ Detection: 7 (before) → 2 (after detection)
├─ RPN: 224 (before) → 8 (after)
├─ AP: High (before) → Low (after)
│
└─ Level 3: Cause of Failure
├─ Cause: "Wrench calibration drift"
├─ Prevention: "Calibration check every 500 uses"
└─ Detection: "Torque verification gauge on line"
Custom Fields for PFMEA Workflows
The following custom fields are typically configured in Process FMEA risksheet columns:
| Field | Level | Purpose |
|---|
pfmSeverity | 2 | Severity rating (1-10 scale) |
premitigationPFMOccurrence / postmitigationPFMOccurrence | 3 | Pre/post occurrence at cause level |
premitigationPFMDetection / postmitigationPFMDetection | 3 | Pre/post detection at cause level |
premitigationPFMAP / postmitigationPFMAP | 3 | Pre/post action priority at cause level |
pfmRPN / pfmRPNPost | 3 | Pre/post RPN (typically formula-calculated) |
preventionControl | 3 | Description of control preventing cause |
detectionControl | 3 | Description of control detecting failure |
effectOfFailure | 2 | Consequence description (used for severity determination) |
scccClassification | 2 | SC/CC classification for safety traceability |
Creating and Editing Process Failure Modes
Process Failure Modes are typically created within a PFMEA document using the Risksheet interactive editor:
- Create a Process Step as Level 1 item (e.g., “Fastening”)
- Add Level 2 Process Failure Mode rows under each process step
- Complete Effect and Severity fields
- Add Level 3 causes with O/D ratings
- Design prevention and detection controls
- Calculate (or manually enter) pre/post RPN and AP scores
- Submit for review and approval
All process failure modes within a PFMEA document are grouped by their parent process step. When exported or reported, failure modes roll up to document totals for RPN distribution and AP summaries.
PFMEA Document Context
Process Failure Modes are exclusive to Process FMEA (PFMEA) documents, which appear in the Risks space alongside Design FMEA and HARA documents. A typical PFMEA document contains:
- 10–30 Process Steps (assembly stations, handling procedures, test operations)
- 20–60 Process Failure Modes (potential failures per step)
- 30–100 Causes (root causes per failure mode)
- 15–40 Control Plan Items (mitigating controls linked to failure modes)
The Process FMEA becomes input to the Control Plan, which translates process controls into manufacturing line specifications and operator procedures.
Reporting and Dashboards
Process Failure Modes aggregate in several standard reports:
| Report | Purpose |
|---|
| System PFMEA Report | Executive summary: RPN distribution (Low/Med/High), high-RPN alerts, process failure mode counts by document |
| FMEA Coverage Report | All-in-one comparison: Design FMEA vs Process FMEA: counts, RPN ranges, control effectiveness metrics |
| Process FMEA Risksheet | Interactive three-level editor: process steps, failure modes, causes, controls, RPN calculations |
| Control Plans Report | Mapping of process failure mode mitigations to Control Plan Items: measurement methods, frequencies, reaction plans |
Process failure modes with post-mitigation RPN >100 trigger dashboard alerts and are flagged for immediate corrective action. These represent unacceptable residual process risk requiring additional controls or design changes.
Integration with Risk Controls
Process Failure Modes link to Risk Control work items via the mitigatedBy link role. A single failure mode can be mitigated by multiple controls (e.g., procedure change + equipment upgrade + inspection). The Risk Control tracks implementation status, evidence, and verification of each mitigation action.
See Also
