How to Estimate PCBA Cost: From BOM to Accurate Quotation

Core Components of PCBA Cost

Understanding the full scope of PCBA (Printed Circuit Board Assembly) cost is essential for accurate budgeting and project feasibility. PCBA cost is a multidimensional system, primarily consisting of the following major components:

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PCB Manufacturing Costs

Includes substrate material costs, processing fees, etc., influenced by board type, number of layers, size, and design complexity. For example, a four-layer board typically costs about twice as much as a double-sided board. Special surface finishes like ENIG (Electroless Nickel Immersion Gold) can increase costs by 20%-30%.

Component Procurement Costs

Component costs account for 40%-60% of the total PCBA cost, and a small decimal error could lead to losses in the tens of thousands. While common components such as resistors and capacitors have stable prices, high-end ICs and BGAs are subject to market fluctuations and international supply constraints.

SMT Assembly Costs

Calculated based on the number of SMT points, the industry typically counts standard SMD components (e.g., resistors, capacitors) as 2 points per piece, QFP and similar mid-sized chips based on pin count, and large chips like BGAs as 4-6 points.

DIP Assembly Costs

Through-hole soldering costs are usually calculated based on pin count, with wave soldering and manual soldering having different unit prices. Hand soldering ranges from 0.08 to 0.15 RMB per pin, while wave soldering is more economical at 0.03 to 0.08 RMB per pin.

Testing and Quality Control Costs

Includes AOI (Automated Optical Inspection), flying probe testing, functional testing, etc. The more test points, the higher the cost. Additional expenses include test fixture development (1500–8000 RMB) and functional test development fees (2000–10000 RMB).

Auxiliary Materials and Operating Costs

Covers costs for auxiliary materials such as solder paste, flux, stencils, and packaging materials, as well as operational expenses like equipment depreciation, utilities, and management costs.

PCB Cost Calculation and Design Optimization

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PCB Cost Calculation Formula and Application

PCB Cost = Material Cost + Process Cost + Special Process Fees

PCB Material Cost Calculation

Single PCB material cost = Price per square meter of PCB ÷ Number of PCBs produced per square meter

Process Cost Factors

· Drilling Costs: Number of holes × hole diameter coefficient (more holes or smaller diameters increase costs)

· Trace Width/Spacing: Precision traces below 0.2mm/0.2mm increase costs by 30%-50%

· Layer Count: Each additional layer increases costs by 40%-60%

Special Process Additions

· Impedance Control: Increases costs by 10%-15%

· Blind/Buried Vias: Increases costs by 25%-40%

· Gold Fingers: Calculated based on gold layer area

PCB Design Optimization Strategies

By optimizing panelization, material utilization can increase from 70% to over 85%, reducing costs by 10%-15%. Tools like Huaqiu DFM can automatically calculate optimal panelization schemes. Avoid features like hole diameters under 0.3mm or trace widths below 0.15mm.

BOM Management

Standardized BOM Process

1. Export the BOM list from the schematic

2. Merge identical component models

3. Standardize naming conventions

4. Specify key parameters

5. Differentiate between substitute and unique part numbers

Merging Component Models

Consolidating identical parts reduces procurement complexity and enables volume discounts.

Naming Standardization

Ensure consistency in units (e.g., use µF/nF for capacitors) to avoid confusion during sourcing.

Key Parameter Labeling

Specify tolerances, voltages, and packaging sizes clearly to ensure correct component selection.

Differentiating Substitute and Unique Part Numbers

Mark alternatives distinctly to allow flexibility without compromising design integrity.

SMT Assembly Cost Calculation

Detailed Explanation of SMT Point Calculation Rules

· Standard SMD Components: 2 points per piece

· Small Chips: 3 points

· Mid-sized Chips: Based on pin count

· Large Chips (e.g., BGA): 4-6 points

Formula: SMT Cost = Number of SMT Points × Unit Price + Stencil Fee + Setup Fee

Steel stencil costs range from 100–800 RMB; setup fees are typically between 500–2000 RMB per batch.

Impact of Unit Price Factors

Different technologies affect pricing; for example, BGA placement is pricier due to X-ray inspection requirements.

Batch Discount Analysis

· 5,000–20,000 Pieces: 8%-12% discount

· Over 20,000 Pieces: 15%-25% discount

DIP Assembly and Testing Cost Calculation

DIP Assembly Cost Calculation

DIP Cost = Number of Through-Hole Solder Points × Unit Price + Wave Soldering Fixture Cost

Fixtures cost between 500–3000 RMB but are reusable across batches.

Testing Cost Structure and Optimization

Testing Cost = Number of Flying Probe Test Points × Unit Price + Functional Test Development Fee + Test Fixture Fee

For small batches, flying probe testing is economical; for mass production, switch to fixtures for a ~60% cost reduction.

Total PCBA Cost Calculation and Practical Case

Total Cost Calculation Formula

PCBA Total Cost = PCB Cost + Component Cost × (1 + Loss Factor) + SMT Cost + DIP Cost + Testing Cost + Packaging and Logistics Cost + (Profit & Management Fees)

Logistics usually account for 1%-3%, profit margins range from 10%-30%.

Quick Cost Estimation Formula

· Standard Double-Sided Board (1.6mm FR4) + Common Components: ≈ 8-15 RMB/100 points

· Four-Layer Board + Precision Components: ≈ 15-28 RMB/100 points

Typical Cost Structure Proportions

· Component Procurement: ~50%

· SMT: ~20%

· PCB: ~10%

· Testing & Logistics: ~10%

· Others: ~10%

PCBA Cost Optimization Strategies

DFM Design Optimization

Set reasonable trace width/spacing (≥0.15mm) to avoid increased production difficulty and higher scrap rates.

Component Procurement Strategy

· Consolidated Procurement: Merge procurement needs to secure volume discounts

· Alternative Materials: Use domestic components to replace imported ones when performance requirements are met

Production Batch Optimization

Merge production runs to reduce line changeovers; plan delivery schedules to avoid expedited orders, which incur additional fees (typically 15%-25% extra).

Process Route Selection

Choose simpler processes where possible: e.g., use lead-free solder paste for basic boards or red glue with wave soldering for boards with large components.

Testing Plan Optimization

Use flying probe tests during prototyping; shift to fixtures during mass production to significantly reduce per-unit testing costs.

PCBA Quotation Process and Time Management

PCB Quotation Process

When complete documentation is provided and no special processes are required, quotations can be completed within the same day. Ensure Gerber files are complete for faster turnaround.

Component Quotation Process

· Common Components: 1-2 days

· Specialty Chips: 3-4 days (due to price fluctuations and supply chain verification)

Processing Fee Quotation

Based on BOM and Gerber files, calculations can be completed within 1-2 days.

Tips for Reducing Quotation Time

· Provide complete documentation, including BOM, Gerber files, and process notes

· Pre-identify long-lead components like FPGAs or specialty ICs

· Establish long-term partnerships with suppliers for shared inventory access

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