6 Steps for an Accurate PCB Assembly Quote

Getting an accurate PCB assembly (PCBA) quote is essential to managing costs, timelines, and quality expectations. A precise quote depends on multiple factors such as the accuracy of design documentation, clarity in assembly type, component sourcing strategy, and access to board fabrication suppliers. From prototype runs to low-to-mid production volumes, aligning quote requests with IPC guidelines (e.g., IPC-A-610, IPC-2612, IPC-1752) helps ensure consistent communication and expectations between OEMs and contract manufacturers.

Key Factors Affecting PCB Assembly Quotes

1. Bill of Materials (BOM) Accuracy

The BOM must be in Excel format and should include:

• Manufacturer and distributor part numbers
• Detailed component descriptions (e.g., capacitors, resistors, ICs, discrete semiconductors)
• Specified quantities, voltage/current tolerances, and part ratings
• Reference designators
• Approved vendor list (AVL) or cross-reference suggestions for alternates

A clean, validated BOM reduces quoting delays, sourcing confusion, and potential cost escalations.

2. PCB Design Files and Technical Drawings

For accurate quoting, assemblers rely on standardized data formats per IPC-2581 or Gerber files. Designers should submit the following:

• Gerber files: Complete with drill data and layer stack-up
• ODB++ or IPC-2581: Optional, but increasingly preferred for intelligent data exchange
• Centroid (XY) file: For automated pick-and-place programming
• Assembly and fabrication drawings: Include mechanical outlines, fiducials, special instructions, and layer callouts
• Schematics: Aid in process review and troubleshooting

Well-prepared documentation reduces NPI delays or costly rework.

3. Assembly Complexity and Process Type

Labor and equipment costs scale with assembly difficulty. Clearly indicate:

• Technology type: SMT, Through-Hole (THT), or Mixed Technology
• Component density: High I/O BGAs, fine-pitch ICs, PoPs, or micro BGAs may require X-ray or 3D AOI
• Double-sided assembly: Adds handling steps and complexity
• Lead-free compliance: If required, specify RoHS per IPC-A-610 Class 2 or 3

Rework considerations: Identify any areas requiring manual rework or non-standard operations

4. Component Sourcing and Availability

Component procurement plays a significant role in cost and lead time:

• Define whether the job is Turnkey, Consigned, or Partial Consignment
• Provide sourcing constraints (e.g., authorized distributors only)
• Specify alternate parts if original components are long lead or obsolete
• Collaborate with EMS providers that offer AVL management and strong supplier networks

5. Testing and Inspection Requirements

Include test strategies and inspection standards during the quoting phase:

• AOI: Automated Optical Inspection for SMT components
• X-ray: Mandatory for BGAs and bottom-terminated components (BTCs)
• Flying Probe Test
• FCT: Functional Circuit Testing based on the end-product use case
• First Article Inspection (FAI): Often required in aerospace, defense, or automotive per IPC J-STD-001

More comprehensive testing improves yield but adds both time and cost.

6. Lead Time

Specify:

• Turnaround expectations: Standard lead times, quick-turn, or expedited builds
• Bare board availability: Include expected fab lead time if not bundled with assembly quote

Be aware that compressed schedules often require faster component sourcing, kitting, and machine setup, which can affect cost.

Tips for Maximizing Quote Accuracy

• Use standardized formats: IPC-2581 or ODB++ enable streamlined quoting
• Double-check part availability: Avoid EOL or constrained components
• List acceptable alternates: Increases sourcing flexibility
• Specify industry class: IPC-A-610 Class 2 (standard), Class 3 (high reliability)
• DFM feedback: Use a manufacturing partner that performs DFM checks on every order. Proactive design reviews can prevent yield losses

An accurate PCB assembly quote is the product of detailed planning, clear communication, and standards-based documentation. By aligning your BOM, design files, and test requirements with IPC guidelines and supplier expectations, you create a smoother quoting process and reduce risk throughout the production lifecycle. Whether you’re working on PCB prototypes or scaling into volume production, a robust and well-documented quote request is a critical step for a successful project.

Learn more about Summit’s assembly services and submit files for a quick quote.