A robust PCBA quotation checklist is the technical foundation that bridges the gap between a design file and a physical, functional circuit board assembly. It goes beyond simple pricing to define the exact scope of materials (BOM), manufacturing data (Gerber), and validation protocols (Testing) required to minimize production risks. By standardizing this input data, engineers and procurement teams ensure that the final quote accurately reflects the complexity, quality standards, and lead times necessary for a successful build.

Key Takeaways

• Data Completeness: A quote is only as accurate as the data provided; missing Pick-and-Place (XY) files or ambiguous BOMs can delay quotes by 2–3 days.
• BOM Validation: Ensure every line item includes a Manufacturer Part Number (MPN); descriptions alone lead to a 15–20% risk of incorrect component selection.
• Attrition Rates: Always account for component overage; standard practice requires 3–5% extra for passives (0402 and smaller) and 1–2% for active ICs to cover machine waste.
• Gerber Precision: Files must be in RS-274X or ODB++ format with clear drill charts; vague drill tolerances often force manufacturers to pause for Engineering Questions (EQ).
• Testing Scope: Define test coverage early; In-Circuit Testing (ICT) typically requires test points on >90% of nets, while Functional Circuit Testing (FCT) relies on specific firmware and jigs.
• Validation Tip: Before submission, run a "dry run" BOM scrub against a distributor database (e.g., DigiKey or Mouser) to identify obsolete parts immediately.
• Decision Rule: If your board contains BGAs with pitch < 0.5mm, you must explicitly request X-Ray inspection in the quotation to ensure voiding compliance.

Contents

• What It Really Means (Scope & Boundaries)
• Metrics That Matter (How to Evaluate It)
• How to Choose (Selection Guidance by Scenario)
• Implementation Checkpoints (Design to Manufacturing)
• Common Mistakes (and the Correct Approach)
• FAQ (Cost, Lead Time, Materials, Testing, Acceptance Criteria)
• Glossary (key terms)
• Conclusion (next steps)

What It Really Means (Scope & Boundaries)

The PCBA quotation checklist serves as the governing document for the entire manufacturing relationship. It is not merely a request for cost; it is a specification of the "build-to-print" requirements. The scope encompasses three distinct pillars: the Bill of Materials (BOM), which dictates what is being built; the Gerber/CAD data, which dictates where and how it is built; and the Testing/Quality criteria, which dictates if the build is acceptable.

Boundaries are critical here. A standard quotation checklist typically covers the assembly labor, PCB fabrication, component procurement, and standard inspection (AOI). It often excludes non-recurring engineering (NRE) for custom test fixtures, conformal coating, or box-build assembly unless explicitly requested. Understanding these boundaries prevents "scope creep" where costs balloon later due to undefined requirements like specific cleanliness standards (e.g., ionic contamination < 1.56 µg/cm² NaCl equivalent) or specific packaging needs.

Metrics That Matter (How to Evaluate It)

To ensure a quotation is actionable and low-risk, specific metrics regarding data quality and manufacturing capability must be evaluated. The following tables outline the critical parameters for the input data (BOM/Gerber) and the expected output quality.

Table 1: Data Input Quality Metrics

Metric	Acceptable Range / Target	Why It Matters	How to Verify
BOM Completeness	100% MPN Coverage	Descriptions (e.g., "10k Resistor") are insufficient and cause sourcing errors.	Check that every row has a valid Manufacturer Part Number.
Component Lifecycle	0% Obsolete / NRND	Obsolete parts halt production; Not Recommended for New Design (NRND) risks future supply.	Run BOM through a supply chain tool (e.g., SiliconExpert, Octopart).
Pick & Place Accuracy	X/Y coordinates to 0.01mm	Ensures precise placement, especially for 0201s and fine-pitch BGAs.	Verify Centroid file export settings in EDA software.
Drill File Tolerance	±3 mil (0.076mm)	Vague tolerances lead to fitment issues for through-hole components.	Review drill chart in Gerber fabrication notes.
Solder Mask Expansion	2–4 mil (0.05–0.10mm)	Prevents solder bridging on fine-pitch ICs.	Inspect Gerber layers using a viewer (e.g., CAM350).
Fiducial Count	Min 3 Global, 2 per BGA	Essential for machine vision alignment during assembly.	Visually confirm fiducials on the copper and paste layers.

Table 2: Manufacturing & Quality Output Metrics

Metric	Acceptable Range / Target	Why It Matters	How to Verify
BGA Voiding	< 25% (IPC Class 2)	Excessive voids reduce thermal and mechanical reliability of the joint.	Request X-Ray inspection reports for all BGA components.
Solder Paste Height	4–6 mils (typical)	Too little paste causes opens; too much causes shorts.	Review SPI (Solder Paste Inspection) data logs.
Component Overage	3–5% (Passives), 1% (Actives)	Machines drop parts; insufficient overage causes short shipments.	Check the "Attrition" or "Overage" line item in the quote.
First Pass Yield (FPY)	> 98% (Mass Production)	Low yield indicates process instability or poor DFM.	Ask for FPY statistics on similar technology builds.
Test Coverage	> 90% (ICT), 100% (Power)	Unverified nets leave latent defects undetected.	Review the "Testability Report" provided by the assembly house.
Ionic Contamination	< 1.56 µg/cm²	High contamination leads to dendritic growth and shorts over time.	Request ROSE test results if reliability is critical.

How to Choose (Selection Guidance by Scenario)

Selecting the right quotation parameters depends heavily on the stage of the product lifecycle and the specific technology requirements. Use these decision rules to tailor the checklist.

1. If you are in the Prototype (NPI) phase, choose a "Turnkey" service where the assembler sources all components to save administrative time, even if material costs are 10–15% higher.
2. If you are in Mass Production, choose a "Consigned" or "Partial Turnkey" model for high-value ICs to control costs, while letting the assembler manage low-cost passives (C-parts).
3. If your board uses Fine-Pitch BGAs (< 0.5mm), choose to mandate 100% X-Ray inspection and include bga voiding control: stencil, reflow, and x-ray criteria in the quality notes.
4. If the product is Class 3 (Medical/Aerospace), choose to require a First Article Inspection (FAI) report that verifies 100% of component values before the full run is populated.
5. If you have Impedance Controlled Traces, choose to include a specific dielectric stackup request in the Gerber notes, specifying the material (e.g., Isola 370HR) and target impedance (e.g., 50Ω ±10%).
6. If the design requires Conformal Coating, choose to specify the coating type (Acrylic, Silicone, Urethane) and the "keep-out" areas clearly on a dedicated mechanical layer.
7. If you require Functional Testing (FCT), choose to provide the test fixture design and firmware executable as part of the RFQ package to get an accurate labor quote.
8. If cost is the Primary Driver, choose to allow "Substitutes Approved" for passive components (resistors/capacitors), allowing the assembler to use house stock brands (e.g., Yageo, Samsung).
9. If lead time is Critical (< 5 days), choose to select components solely from domestic distributors (e.g., DigiKey, Mouser) and avoid parts showing "Factory Stock" or "Allocation."
10. If the board has Thick Copper (> 2oz), choose to increase the minimum spacing rules in your design and request a heavy-copper specific thermal profile for reflow soldering.

Implementation Checkpoints (Design to Manufacturing)

Moving from a quote to a physical board requires a disciplined implementation process. This checklist ensures that the data handed off matches the quote and manufacturing capabilities.

1. Bom Scrubbing and Validation

• Action: Export the BOM and verify every MPN against a live distributor database.
• Acceptance Check: 100% of MPNs show "Active" lifecycle status and have stock available for the build quantity + 5% attrition.
• Why: This is how to avoid bom mismatch and substitution risk in turnkey pcba projects; catching obsolete parts here prevents weeks of delay.

2. Gerber File Generation

• Action: Generate RS-274X or ODB++ files including all copper layers, solder mask, silkscreen, drill files, and board outline.
• Acceptance Check: Load files into a third-party viewer (e.g., DFM Now) to verify layer alignment is within 0.05mm.

3. Centroid (Pick & Place) File Creation

• Action: Export the XY coordinate file including Designator, Layer, X-Mid, Y-Mid, Rotation, and Package.
• Acceptance Check: Verify that rotation angles match the footprint orientation (e.g., Pin 1 alignment) for all ICs.

4. DFM Review (Design for Manufacturability)

• Action: Submit files for a preliminary DFM check by the Turnkey Assembly provider.
• Acceptance Check: Receive a DFM report with 0 "Showstopper" errors (e.g., missing solder mask dams < 4 mil).

5. Test Point Assignment

• Action: Ensure critical nets have accessible test points (min 0.8mm diameter) for ICT or flying probe.
• Acceptance Check: Test coverage report shows > 90% net accessibility.

6. Engineering Question (Eq) Resolution

• Action: Respond to manufacturer EQs regarding stackup, impedance, or component footprints.
• Acceptance Check: All EQs closed within 24 hours to maintain the quoted lead time.

7. Solder Paste Stencil Approval

• Action: Review the stencil aperture modifications proposed by the assembler.
• Acceptance Check: Apertures for BGAs and QFNs are reduced (typically 10–20%) to control solder volume and prevent bridging.

8. First Article Inspection (Fai)

• Action: Request a full FAI report for the first assembled unit.
• Acceptance Check: First Article Inspection report confirms all component values measure within tolerance and polarity is correct.

9. Reflow Profile Tuning

• Action: Manufacturer runs a thermal profiler board to set oven zones.
• Acceptance Check: Time Above Liquidus (TAL) is 45–75 seconds, and peak temperature does not exceed component max ratings (usually 245°C–260°C).

10. Final Quality Audit

• Action: Perform visual and functional checks on the production lot.
• Acceptance Check: Shipment includes Certificate of Compliance (CoC) and X-Ray images for BGA components.

Common Mistakes (and the Correct Approach)

Even with a checklist, specific errors frequently derail PCBA projects. Understanding the impact and the fix is crucial for a smooth transaction.

1. Mistake: Providing only a "Description" in the BOM (e.g., "100nF Cap").

   • Impact: Assembler selects a part with incorrect voltage or temp coefficient, causing field failure.
   • Fix: Always provide a specific Manufacturer Part Number (MPN).
   • Verify: BOM columns must include "Manufacturer" and "MPN".

2. Mistake: Ignoring Component Orientation in Centroid Files.

   • Impact: Polarized capacitors or diodes are placed in reverse, leading to immediate short circuits.
   • Fix: Mark Pin 1 clearly on the Silkscreen and Assembly drawing.
   • Verify: Check the Assembly Drawing layer against the Centroid file rotation.

3. Mistake: Omitting X-Ray Requirements for BGAs.

   • Impact: Hidden solder bridges or excessive voiding under the BGA go undetected.
   • Fix: Specify bga voiding control: stencil, reflow, and x-ray criteria in the quote notes.
   • Verify: Confirm the quote includes a line item for "X-Ray Inspection."

4. Mistake: Failing to Define Panelization.

   • Impact: Boards arrive as singles, making automated assembly inefficient or impossible.
   • Fix: Request "Array/Panel" delivery with breakaway rails (typically 5–10mm) and fiducials on the rails.
   • Verify: Review the panel drawing provided by the fab house before production.

5. Mistake: Incomplete "Do Not Populate" (DNP) Instructions.

   • Impact: Expensive parts are placed on unneeded footprints, wasting money and potentially causing shorts.
   • Fix: Add a "DNP" or "Fitted" column in the BOM; mark DNP components clearly.
   • Verify: Cross-reference the BOM DNP list with the pick-and-place file.

6. Mistake: Using Ambiguous Drill Charts.

   • Impact: Manufacturer guesses if holes are plated (PTH) or non-plated (NPTH), affecting grounding and mounting.
   • Fix: Separate PTH and NPTH into different tools or files; specify tolerances clearly.
   • Verify: Check the Gerber drill file header for tool definitions.

7. Mistake: Forgetting to Specify PCB Surface Finish.

   • Impact: Receiving HASL (uneven) instead of ENIG (flat) causes placement issues for fine-pitch BGAs.
   • Fix: Explicitly state "ENIG" or "Immersion Silver" in the fabrication notes.
   • Verify: Check the quote line item for "Surface Finish."

8. Mistake: Not Accounting for Moisture Sensitivity Levels (MSL).

   • Impact: Components crack during reflow due to absorbed moisture (popcorning).
   • Fix: Ensure the assembler follows J-STD-033 for baking MSL parts.
   • Verify: Check that the assembler has controlled storage and baking ovens.

FAQ (Cost, Lead Time, Materials, Testing, Acceptance Criteria)

Q: How does the number of unique line items (BOM lines) affect the quotation cost? A: The number of unique line items directly impacts the "feeder setup" labor cost.

• Each unique part requires a separate feeder slot on the pick-and-place machine.
• More lines mean longer setup times and higher NRE charges.
• Consolidating values (e.g., using 10k resistors everywhere instead of 10k and 10.2k) reduces cost.

Q: What is the standard lead time for a turnkey PCBA quote? A: A standard turnkey quote typically takes 24–48 hours to generate.

• Delays occur if the BOM lacks MPNs or if Gerber files are corrupt.
• Complex BOMs with > 200 line items may take 3–4 days for sourcing verification.
• "Quick-turn" quoting options are often available for standardized designs.

Q: How do I handle "Substitute Parts" in the quotation checklist? A: You should explicitly define your substitution policy in the RFQ.

• "No Substitutes": Manufacturer must buy the exact MPN (higher risk of lead time issues).
• "Passive Subs Allowed": Manufacturer can use equivalent resistors/capacitors (lower cost, faster).
• "Approval Required": Manufacturer proposes subs, but you must sign off (balanced approach).

Q: What testing should I request for a batch of 50 prototype boards? A: For small prototype batches, heavy fixture-based testing is usually cost-prohibitive.

• AOI (Automated Optical Inspection): Essential for all builds to check placement and polarity.
• Flying Probe: Good for prototypes as it requires no fixture, though it is slow.
• Visual Inspection: Manual check under magnification for workmanship.

Q: How is component overage (attrition) calculated in the quote? A: Assemblers buy more parts than the BOM quantity to account for machine waste.

• Passives (0402+): Typically 3–5% overage or a minimum of 50–100 extra parts.
• Passives (0201): May require higher overage due to handling difficulty.
• Expensive ICs: Usually 0–1% overage; often supplied on cut tape with a leader extender.

Q: What is the difference between NRE and Unit Cost in the quote? A: NRE (Non-Recurring Engineering) is a one-time setup fee, while Unit Cost is per board.

• NRE: Stencils, machine programming, test fixtures, tooling.
• Unit Cost: PCB material, components, assembly labor per minute.
• Re-orders usually exclude NRE unless the design changes.

Q: How do I verify that the assembler used the correct PCB material (e.g., FR4 TG170)? A: Verification is done through documentation and marking.

• Request a "Material Certificate" or CoC from the laminate supplier.
• Check the PCB edge markings (UL watermark) which often indicate the material grade.
• Specify the material explicitly in the Components & BOM notes.

Q: What are the acceptance criteria for solder joints? A: Acceptance is generally based on IPC standards.

• IPC-A-610 Class 2: Standard industrial/consumer (most common).
• IPC-A-610 Class 3: High reliability (medical, aerospace, life support).
• Criteria cover wetting angles, solder volume, and component alignment.

Glossary (Key Terms)

Term	Definition
AOI	Automated Optical Inspection. A camera-based system that scans assembled boards for missing parts, polarity errors, and solder quality.
BOM	Bill of Materials. The comprehensive list of all components, including MPNs, quantities, and reference designators.
Centroid File	Also known as the Pick-and-Place or XY file. Contains the coordinates and rotation for every component on the PCB.
DFM	Design for Manufacturability. The process of designing a PCB layout to minimize manufacturing errors and costs.
EQ	Engineering Question. A formal query from the manufacturer to the designer to clarify ambiguities in the data package.
FAI	First Article Inspection. A detailed verification report of the first unit produced to ensure process validity before mass production.
Fiducial	A copper marker on the PCB used by assembly machines for optical alignment and correction.
Gerber	The standard file format (RS-274X) used to convey PCB fabrication data (copper layers, drill, mask) to the manufacturer.
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Conclusion

pcba quotation checklist (bom, gerber, testing) is easiest to get right when you define the specifications and verification plan early, then confirm them through DFM and test coverage. Use the rules, checkpoints, and troubleshooting patterns above to reduce iteration loops and protect yield as volumes increase. If you’re unsure about a constraint, validate it with a small pilot build before locking the production release.

Related links

• Turnkey Assembly
• First Article Inspection
• Components & BOM
• Design for Manufacturability