RFQ Checklist for Coreless DC Motor OEM Projects
A practical RFQ checklist to speed up technical alignment, quoting, and sample planning for custom coreless DC motor sourcing.
Procurement and engineering teams can cut 1-2 quote rounds by sending a structured RFQ package from day one.
Why Most Motor RFQs Lose Time
Delays usually come from three gaps:
- Operating targets are not tied to real load points.
- Mechanical interface details are incomplete.
- Sample acceptance criteria are not agreed before build.
RFQ Data Pack Buyers Should Send
Use this as your minimum RFQ template.
| RFQ field | Why it matters | Minimum format |
|---|---|---|
| Application and duty profile | Defines real stress and control mode | One-paragraph use case plus duty cycle (%) |
| Voltage window | Prevents mismatch between nominal and worst-case behavior | Rated, min startup, and max transient voltage |
| Speed and torque targets | Enables usable winding and gear ratio selection | No-load speed, load speed, target torque at each load point |
| Current and power limits | Protects system-level electronics and thermal budget | Continuous current limit and peak duration |
| Envelope constraints | Avoids packaging redesign in later phases | Motor OD, length, shaft dia/length, connector or lead-out direction |
| Noise and vibration limits | Avoids subjective "too noisy" disputes | dBA limit and test distance (for example 10 cm) |
| Lifetime target | Aligns bearing and brush strategy | Hours or cycles under defined load and temperature |
| Environmental conditions | Controls material and lubrication choices | Temperature range, humidity, shock/vibration level |
RFQ Readiness Flow (Use Before Sending to Suppliers)
Commercial Inputs That Improve Quote Accuracy
- Volume split by phase: sample, pilot, and annual mass production.
- Required lead-time window for each phase.
- Compliance list: RoHS, REACH, and any customer-specific file pack.
- Packaging and incoming inspection expectations.
Without these four inputs, "best price" comparisons are often not apples-to-apples.
What Buyers Should Request Back from Suppliers
Ask suppliers to return these items in the first response:
- Performance curve at your actual voltage window, not only nominal voltage.
- Drawing with tolerances for shaft, mounting, and lead exit.
- Current draw and temperature-rise data at each target load point.
- Reliability plan: sample size, test conditions, and pass/fail logic.
- Change-control commitment for winding wire, magnet grade, and key components.
Sample Acceptance Scorecard (Before Mass-Production Decision)
| Checkpoint | Pass rule | Risk if skipped |
|---|---|---|
| Electrical consistency | Key parameters stay within agreed tolerance across sample set | Field return risk from batch drift |
| Startup reliability | Starts at minimum supply voltage and low-temperature boundary | Intermittent no-start in real use |
| Noise and vibration | Meets agreed test method and threshold | Subjective disputes and redesign delay |
| Mechanical fit | Passes fixture and final assembly fit test | Late-stage housing or shaft changes |
| Thermal margin | Temperature rise within system budget at duty cycle | Early failure or derating requirement |
RFQ Completeness Scoring Model (Internal Gate)
Before sending RFQ, score your package on a 100-point scale:
| Module | Weight | Pass threshold | Practical pass check |
|---|---|---|---|
| Load and duty profile quality | 25 | >= 20 | At least 3 real operating points and one peak case are defined |
| Mechanical interface clarity | 25 | >= 20 | Shaft/mounting drawings include tolerance and datum notes |
| Acceptance criteria specificity | 30 | >= 24 | Startup/noise/thermal have numeric thresholds and test method |
| Commercial readiness | 20 | >= 16 | Phase volume, lead-time target, and compliance list are complete |
Recommended internal release rule:
- Total score >= 80.
- No module below its threshold.
- If rule 1 passes but any module fails, hold RFQ and repair that module first.
Common Buyer Mistakes
- Asking for "high speed and high torque" without a load curve.
- Skipping shaft tolerance and coupling details.
- Locking unit price before agreeing sample acceptance criteria.
- Comparing quotes with different test assumptions.
Practical Rule
Treat RFQ quality as a schedule lever, not only a sourcing document.
A complete RFQ package usually saves more time and rework cost than a fast but incomplete quote request.
Downloadable Buyer Templates
Example: RFQ Review in a Typical New Product Program
Use this as a practical baseline when you brief procurement, R&D, and quality in the same meeting:
| Item | Basic RFQ | Structured RFQ |
|---|---|---|
| Technical clarification rounds | 3-4 | 1-2 |
| Time to sample release decision | 3-5 weeks | 1-2 weeks |
| Quote comparability | Low | High |
| Late-stage interface change risk | High | Medium to low |
The exact timing still depends on product complexity and internal approval speed, but this baseline is realistic for most OEM starts.
7-Day RFQ Improvement Sprint (Buyer Team Execution Plan)
| Day | Owner | Output | Done definition |
|---|---|---|---|
| Day 1 | Product + R&D | Load envelope draft | 3 core points plus peak/startup points documented |
| Day 2 | ME | Interface drawing pack | Shaft/mount tolerances reviewed by assembly owner |
| Day 3 | QA | Acceptance criteria draft | Noise/startup/thermal methods and limits defined |
| Day 4 | Procurement | Commercial assumptions | Phase quantities and target lead times approved |
| Day 5 | Cross-functional review | RFQ package v1 | All mandatory fields filled and no placeholder text |
| Day 6 | Supplier-facing rehearsal | Clarification list | Team can answer top 10 likely supplier questions |
| Day 7 | Final sign-off | RFQ release | Internal completeness score meets release rule |
Related Buyer Resources
After your RFQ draft is complete, these pages help finalize commercial and execution controls:
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