Overview
Characteristics serve as critical bridge elements in the data model, connecting design requirements to failure analysis and manufacturing control plans. They capture:
- Target specifications for design attributes (e.g., sensor response time, material hardness, voltage stability)
- Measurement methods to verify compliance
- Tolerance ranges defining acceptable variation
- Classification as Safety Critical (SC) or Critical Characteristic (CC) under IATF 16949
- Relationships to failure modes (FMEA) and control plan items (APQP)
Characteristics exist at two levels:
| Level | Purpose | Example |
|---|
| Design Characteristics | Specify measurable product attributes derived from Design Requirements | Camera sensor focal length ± 0.5mm, ECU response latency < 50ms |
| Process Characteristics | Define measurable manufacturing process parameters that ensure consistent output | Solder reflow temperature 245–260°C, PCB press force 500–600 kg |
Core Properties
| Name | Type | Default | Description |
|---|
ID | String | Auto-generated | Unique identifier (e.g., CHAR-0342). Automatically assigned by Polarion. |
Title | String | Required | Short descriptive name (e.g., “Camera Module Focal Length”). Appears in all reports and traceability matrices. |
Description | Text | Optional | Detailed explanation of what is being measured, why it matters, and any relevant context (regulatory, safety, functional). |
Status | Enum | Draft | Workflow state: Draft → In Progress → In Review → Approved. Drives document publication readiness. |
Assignee | User | Unassigned | Owner responsible for specification, measurement method definition, and acceptance criteria. |
Priority | Enum | Normal | None, Low, Normal, High, Urgent. Reflects criticality in design and manufacturing. |
Category | Multi-Select | Empty | Organizational tags (e.g., “Electrical”, “Mechanical”, “Safety-Critical”). Enables filtering and reporting. |
Hyperlinks | Link Set | Empty | External document references (e.g., supplier datasheets, test procedures, standards). |
Attachments | File Set | Empty | Supporting files: measurement reports, tolerance stack-up analyses, simulation results, acceptance criteria matrices. |
Comments | Thread | Empty | Collaborative discussion thread for review feedback, clarifications, and decision rationale. |
Custom Fields (Characteristic-Specific)
Specification Properties
| Name | Type | Default | Description |
|---|
characteristicId | String | Auto-generated | Unique short identifier (e.g., “CHAR-001”). Used in control plans, risksheets, and reports. Enables quick reference in manufacturing environments. |
characteristicType | Enum | Product | Distinguishes between Product (part attribute) and Process (manufacturing parameter). Controls visibility in Characteristics vs. Manufacturing Characteristics sheets. |
targetValue | Decimal/String | Required | Nominal or desired specification value (e.g., 50.0, 25°C, ”< 100 ms”). Must be measurable and repeatable. |
toleranceType | Enum | Bilateral | Format for tolerance specification: Bilateral (±), Upper Only (X max), Lower Only (X min), Range (min–max). |
toleranceUpper | Decimal | Optional | Upper tolerance limit (e.g., 50.5 for ±0.5). Defines maximum acceptable value. |
toleranceLower | Decimal | Optional | Lower tolerance limit (e.g., 49.5 for ±0.5). Defines minimum acceptable value. |
toleranceDisplay | String | Computed | Read-only merged display of tolerance (e.g., “49.5–50.5” or “±0.5”). Automatically formatted from toleranceType and limit values. |
unit | String | Optional | Measurement unit (e.g., mm, μm, ms, A, °C, dB, %). Appears in all specifications and test reports. |
measurementMethod | Text | Required | How the characteristic is measured or verified: Inspection (visual/dimensional), Test (functional/performance), Analysis (calculation/simulation), Supplier Data (incoming inspection). |
acceptanceCriteria | Text | Required | Clear pass/fail rule (e.g., “Value within ±0.5 mm when measured at 20°C with calibrated calipers ISO 3611”). Removes ambiguity in acceptance decisions. |
classification | Enum | None | Safety/quality classification per IATF 16949: None, SC (Special Characteristic), CC (Critical Characteristic). Drives visual highlighting in control plans. |
Relationship & Traceability
| Name | Type | Default | Description |
|---|
refines | Link | None | Many-to-one link to parent Design Requirement(s) that this characteristic operationalizes. Enables bidirectional RTM traceability. Cardinality: a characteristic refines 1–N design requirements. |
assessedBy | Link | None | Many-to-many backlink from Failure Mode(s) in FMEA analysis that identify how this characteristic could fail. Automatically populated by failure mode linking. |
linkedTo | Link | None | Flexible link role for custom relationships (e.g., to supplier specifications, test cases, standards clauses). |
allocationRationale | Text | Optional | Engineering justification for tolerance and acceptance criteria (e.g., “Tolerance derived from stack-up analysis per GD&T; acceptance criteria verified via Design Verification Test DV-023”). |
designElementAllocation | Text | Optional | Which design component(s) or subsystem(s) the characteristic applies to (e.g., “Camera Module Lens Assembly”; enables multi-level traceability. |
SC/CC Classification and Visual Treatment
Characteristics marked as SC (Special Characteristic) or CC (Critical Characteristic) receive special attention in manufacturing and quality control:
| Classification | Badge Color | Row Background | Meaning | Workflow Impact |
|---|
| SC | Orange (#ff8c00) | Light orange (#ffe6cc) | Special Characteristic per IATF 16949; requires enhanced process control | 100% first-piece inspection; SPC charting; control plan mandatory |
| CC | Red (#c62828) | Light red (#ffcccc) | Critical Characteristic affecting safety or functionality | Advanced control plan; reduced AQL; possible 100% inspection; formal sign-off required |
| None | Gray (default) | White | Standard characteristic; routine inspection applicable | Standard control plan; normal AQL acceptance; normal workflow |
Characteristics classified as SC or CC trigger mandatory control plan items. Failure to establish controls for SC/CC characteristics is a non-compliance finding in automotive audits (IATF 16949). All SC/CC characteristics must have corresponding entries in the Control Plan risksheet with defined measurement method, sample size, and reaction plan.
Relationship Diagram
The characteristic acts as the bridge between static design intent (requirements) and dynamic manufacturing control (control plans) while serving as the assessment target for failure analysis (failure modes).
Linked Work Item Types
| Target Type | Link Role | Cardinality | Usage Example |
|---|
| Design Requirement | refines | N:1 or N:N | Multiple characteristics operationalize a single design requirement (e.g., three characteristics for “Camera Module Performance” requirement) |
| Failure Mode | assessedBy (backlink) | N:N | A characteristic can be assessed by multiple failure modes (e.g., “Lens Coating Durability” assessed by environmental stress failures). Failure modes link forward to characteristics. |
| Control Plan Item | See control-plan-item.md | 1:N | Each characteristic can have multiple control plan items (e.g., incoming inspection, in-process, final inspection) |
| Function | Indirect via DesReq | N:N | Characteristics support verification that functions work correctly; linked through intermediate Design Requirement(s) |
PowerSheet Integration
Characteristics appear in three PowerSheet configurations:
1. Characteristics Sheet
Comprehensive view of all product and process characteristics with full specification details:
| Column Group | Columns | Purpose |
|---|
| Identification | ID, Title, Type (Product/Process) | Basic reference |
| Specification | Target Value, Unit, Tolerance Type, Upper/Lower Limits | Measurement definition |
| Control | Classification (SC/CC), Measurement Method, Acceptance Criteria | Quality control parameters |
| Traceability | Refines (Design Req Link), Count of Failure Modes | RTM and risk linkage |
| Status | Workflow State, Assignee, Priority | Governance |
2. Component Characteristics Sheet (per Component)
Filtered view showing only characteristics for a specific component:
- Component Name (from parent System Element)
- Product Characteristics (Design attributes)
- Sensor Response Time: 10-15 ms
- Operating Temperature: -40C to +85C
- Vibration Tolerance: up to 10 g @ 50-500 Hz
- Process Characteristics (Manufacturing)
- Solder Temperature: 245-260C
- Assembly Pressure: 500-600 kg/cm2
3. Control Plan Sheet
Links characteristics to control plan items and manufacturing control strategies:
| Characteristic | Measurement Method | Sample Size | Control Frequency | Reaction Plan |
|---|
| Solder Joint Shear Strength | Pull Test ISO 4545 | 1 per batch | Every 8 hours | Adjust reflow profile |
| Component Lead Pitch | Vision Inspection | 100% first piece | Per lot change | Rework or scrap |
Risksheet Integration
In DFMEA and PFMEA riskhseets, characteristics appear as:
- Assessment Target: Failure modes “assess” characteristics to identify failure mechanisms (e.g., “Solder Joint Fatigue” assesses “Solder Joint Shear Strength”)
- Level 1 Grouping (in some PFMEA configurations): Process Characteristics form the top level of hierarchy, with failure modes as Level 2
- Classification Display: SC/CC badges rendered with color-coded background; enables instant recognition in crowded FMEA tables
- Control Link: Characteristics linked to risk controls that define how the failure will be mitigated in the design or manufacturing process
Example PFMEA structure:
- Process Characteristic: Wave Solder Temperature
- Failure Mode: Temperature Too High
- Effect: Component Thermal Damage
- Cause: Thermostat Failure
- S: 8 | O: 3 | D: 4 | AP: H
- Control: SPC Monitoring + Backup Thermostat
- Failure Mode: Temperature Too Low
- Effect: Cold Solder Joint
- Cause: Heating Element Degradation
- S: 7 | O: 2 | D: 5 | AP: M
- Control: Preventive Maintenance Schedule
Custom Field Dependencies
- toleranceType controls which tolerance limit fields are required. Set to Bilateral to require both Upper and Lower; set to Upper Only to require only toleranceUpper.
- characteristicType filters display in PowerSheets. Product characteristics appear in design-focused views; Process characteristics appear in manufacturing-focused sheets.
- classification (SC/CC) auto-triggers review flag in workflow. SC/CC characteristics cannot transition to Approved status without assigned control plan items.
- acceptanceCriteria must reference measurementMethod; they work together to define complete acceptance logic (e.g., “Measured via method X; passes if value ≤ Y”).
Workflow States
Characteristics follow the standard document workflow:
Characteristics cannot be used in control plans or manufacturing workflows until Approved status is reached. In-progress characteristics are visible for review and comment but not yet binding.
Creating and Linking Characteristics
- Create in Design Space under component folder
- Specify target value, tolerance, unit, and measurement method
- Classify as SC or CC if applicable (automotive quality standards)
- Link to parent Design Requirement via
refines relationship
- Validate against failure modes in FMEA (failure mode links forward to characteristic)
- Transition to Approved when accepted by design review
- Use in Control Plan — Control Plan Items reference approved characteristics to define manufacturing controls
Example: Camera Module Focal Length Characteristic
ID: CHAR-0342
Title: Camera Module Focal Length
Type: Product
Target Value: 50.0
Unit: mm
Tolerance: Bilateral ± 0.5
Upper Limit: 50.5
Lower Limit: 49.5
Measurement Method: Optical bench measurement per ISO 9012 at 20°C ± 2°C
Acceptance Criteria: Value within 49.5–50.5 mm; measured on calibrated
optical bench in climate-controlled lab
Classification: SC (affects sensor image quality)
Refines: [Design Requirement] Camera Module Optical
Performance (DR-0156)
Assessed By: [Failure Mode] Lens Decentering (FM-0234)
[Failure Mode] Manufacturing Tolerance Stack-Up (FM-0235)
Allocation: Camera Module Lens Assembly (component CAMERA-MOD-001)
See Also
