Most RFQs fail because they describe part geometry but not decision-critical requirements. Suppliers then quote with different assumptions, and buyers cannot compare offers fairly.
Below is the RFQ structure that sourcing and engineering teams can use together in live supplier rounds.
1. Define project intent first
Your RFQ should start with one clear statement:
- Application and failure consequence
- Prototype objective (fit check, performance validation, pilot release)
- Target launch timeline
Without this context, suppliers optimize for different goals and quote variance increases.
2. Mandatory technical fields
Use this minimum technical pack:
| Field | What to Provide | Why It Matters |
|---|---|---|
| Performance target | Pull force / flux / position requirement + test condition | Prevents grade-only quoting ambiguity |
| Operating environment | Continuous/peak temperature, media exposure, duty cycle | Drives material and retention method selection |
| Mechanical interface | 2D drawing with critical dimensions + datum definition | Controls tolerance stack and fixture plan |
| Material constraints | Required/forbidden materials, coating expectations | Reduces redesign risk after quote |
| Reliability expectation | Cycle life target and critical failure mode | Aligns test method before pilot |
3. Attach the right files
At minimum:
- 2D PDF with tolerances and datums
- 3D CAD (STEP preferred when available)
- Target validation plan or acceptance note
If one of these is missing, call it out explicitly so suppliers do not guess silently.
4. Specify acceptance criteria, not only features
Write measurable acceptance lines:
- Dimensional acceptance (critical features)
- Functional acceptance (pull-force/flux window)
- Cosmetic acceptance where relevant
Also define test condition boundaries (temperature, fixture type, measurement position).
5. Separate prototype from production assumptions
This is where many cost disputes start.
Prototype section should include:
- Sample quantity
- Required lead time
- Validation output expected
Production section should include:
- Forecast volume band
- Cost target logic
- Change-control expectations after approval
6. Include commercial control fields
Mandatory commercial lines:
- Incoterm and destination
- NRE handling model (itemized + rebate or reuse terms)
- Payment milestones tied to deliverables
This keeps engineering and commercial closure synchronized.
7. RFQ comparison framework for buyers
When multiple quotes return, compare on normalized fields:
- Assumption completeness
- Validation scope coverage
- Risk controls and fallback plan
- NRE transparency
- Prototype-to-production continuity
Lowest unit price with weak assumptions is usually the most expensive path later.
8. RFQ checklist before sending
Before sending, confirm:
- All critical dimensions and datums are labeled
- Performance target includes test condition
- Environment profile is complete
- Prototype and production sections are separated
- NRE logic and ownership expectations are written
In practice, this checklist shortens quote revision cycles and reduces pilot-stage delay.
8. Advanced Deep Dive: The Impact of Magnetization Angle Tolerances
In precision sensor applications, defining the mechanical dimensions is not enough. The magnetic vector itself has a tolerance.
Case Study: Rotary Encoder Misalignment
- The Problem: An OEM specified a diametrically magnetized ring magnet with strict mechanical tolerances (±0.02mm). However, the angle of magnetization (the true magnetic north/south split) was deviating by up to 3 degrees relative to the mechanical keyway. This caused unacceptable phase-shift errors in the encoder output.
- The Specification Fix: We updated the drawing to explicitly include a Magnetic Declination Tolerance of ±0.5 degrees relative to Datum A (the keyway).
- The Manufacturing Fix: We implemented a custom-keyed magnetizing fixture that physically locked the rotor's keyway into perfect alignment with the magnetizing coils during the high-voltage pulse.
- Takeaway: If the angle of the field matters, it must be explicitly toleranced and fixtured.
If you want a fast pre-quote review, send your draft package to [email protected].
