Characteristic Custom Fields

Overview

Characteristic work items represent measurable design properties (e.g., braking distance, battery voltage tolerance, acceleration response time) that directly impact product quality, safety, and compliance. Custom fields support both design specification (target values and tolerances) and traceability to failure modes and control plans.

Characteristic custom fields bridge the gap between design requirements and manufacturing control. They capture the “what to control” specification that drives process control plans, statistical process control (SPC) monitoring, and verification test acceptance criteria.

Classification Fields

Field Name	Type	Default	Description
classification	Enum	(none)	Categorizes characteristic type: `standard`, `safety-critical` (SC), `critical-component` (CC), or `process-parameter`. ISO 26262 SC designates characteristics requiring ASIL decomposition. AIAG SC/CC designates special characteristics requiring enhanced control methods. Determines control plan rigor and inspection frequency.

Classification Usage Matrix

Classification	Source Standard	Control Plan Impact	Verification
standard	Design Intent	Standard control	Sampling inspection
safety-critical	ISO 26262 ASIL	100% inspection +SPC	Enhanced verification
critical-comp	AIAG-VDA PPAP	Continuous SPC+audit	Capability studies
process-param	APQP	In-process monitoring	Process capability

When a characteristic is marked SC or CC, all linked failure modes automatically inherit higher rigor requirements. Control plans must include reactive measures (detection + correction) and documented traceability to risk mitigation strategies.

Target Value and Tolerance Fields

Field Name	Type	Default	Description
targetValue	String	(empty)	Nominal or ideal specification value for the characteristic. Format: numeric with optional unit suffix (e.g., `98.5 mm`, `5.2 V`, `150 ms`). Represents the design intent specification that manufacturing processes should achieve. Used in control plan target and as pass/fail threshold for verification test cases. Does not include tolerance—represents a single point value.
tolerance	String	(empty)	Acceptable deviation from target value, defining upper and lower specification limits (USL/LSL). Format: bilateral notation `±X` (e.g., `±0.5 mm`), range notation `X to Y` (e.g., `98.0 to 99.0 mm`), or asymmetric `+X / -Y` (e.g., `+1.0 / -0.8 V`). Specification limits = targetValue ± tolerance. Used in control chart limits (control limits typically ±2σ, specification limits are USL/LSL).

Target Value and Tolerance Example

Characteristic: Brake Pedal Effort (Engagement)

targetValue: 70 N
tolerance:  ±5 N

Specification Limits:
  Upper Specification Limit (USL) = 70 + 5 = 75 N
  Lower Specification Limit (LSL) = 70 - 5 = 65 N

Control Plan:
  Measurement Technique: Force gauge per ISO 6954
  Sample Size: 5 parts per shift
  Sample Frequency: Every 4 hours
  Control Limits: ±2σ = ±3 N (typical for normal process)
  Reaction Plan: If any part > 75 N or < 65 N, stop production and investigate

Tolerance may be entered as free-text notes if the characteristic is qualitative or environmental (e.g., ±0.5 mm for dimensions, operating temperature 0–40°C for operational constraints, visual inspection per AQL 1.5 for attribute characteristics).

Traceability and Integration Fields

Characteristic-to-FailureMode Relationship

Characteristics link to failure modes through the failureModes relationship, enabling simultaneous review of design intent and associated risks:

This relationship is used in the Component Characteristics PowerSheet to display failure modes in a denormalized grid, enabling traceability from design parameter to risk analysis in a single view.

Characteristic-to-ControlPlan Integration

Control Plan Items reference characteristics through the controlPlanItems relationship to define the controls required: Control Plan Item Custom Fields document the measurement and reaction strategy for each characteristic.

Field Organization in PowerSheets

Characteristics Sheet View

Column	Field	Purpose
ID	objectId	Work item identifier (e.g., `CHAR-001`)
Title	title	Characteristic description (e.g., `Brake Pedal Engagement Force`)
Target Value	targetValue	Nominal specification value
Tolerance	tolerance	Acceptable deviation from target
SC/CC	classification	Safety-critical or critical-component indicator (orange/red badge)

Component Characteristics Sheet — Dual-Section Layout

The Component Characteristics PowerSheet displays two sections: Characteristics Section (Green Header)

Characteristic ID, Title, Target Value, Tolerance, SC/CC Classification
Each row represents one characteristic
Collapse-to summary view for executive reporting

Failure Modes Section (Red Header)

Linked failure modes from component DFMEA/PFMEA
Failure Mode ID, Description, Final Action Priority
Color-coded AP: green (Low), orange (Medium), red (High)
Progressive workflow: view without failure modes during design phase, enable during FMEA phase

Without Failure Modes View

Progressive workflow support: switch to Without Failure Modes view during characteristic definition (V-model left side, before FMEA), then enable full view during FMEA execution (right side):

Design Phase              FMEA Phase
    │                        │
    ├─ Characteristic       ├─ Characteristic (same)
    │   • ID                 │   • ID
    │   • Target Value       │   • Target Value
    │   • Tolerance          │   • Tolerance
    │   • SC/CC (NO FMs)     │   • SC/CC
    │                        │   • Failure Mode 1 (FM1-001)
    │                        │   • Failure Mode 2 (FM1-002)
    │                        │   • Failure Mode 3 (FM1-003)

SC/CC Classification Color Coding

The classification field uses conditional rendering in PowerSheets to provide visual risk indication:

Value	Display	Color	Meaning
`standard`	(no badge)	default	Standard characteristic, normal control
`safety-critical`	SC	orange	ISO 26262 ASIL-driven, 100% inspection required
`critical-component`	CC	red	AIAG special characteristic, continuous monitoring
`process-parameter`	(no badge)	default	Process control variable, in-line monitoring

SC (Safety-Critical): Derived from ISO 26262 HARA/ASIL analysis. Characteristic must be controlled to prevent functional safety failures. Requires design FMEA with risk mitigation and enhanced verification.
CC (Critical Component): Derived from AIAG-VDA PPAP/FMEA special characteristics. Characteristic critical for product/process performance. Requires control plan with sampling + SPC, enhanced inspection at receipt and in-process, and capability study (Cpk ≥ 1.33).

Custom Field Definitions (XML Reference)