Designing, fabricating and assembling printed circuit boards entails numerous cost elements. Determining a final PCB price requires combining costs from the board fabrication processes, components, testing, logistics and margin. This article provides an overview of the key factors influencing end PCB pricing and how electronics manufacturers can estimate and manage board costs.
PCB Fabrication Cost Drivers
The bare PCB fabrication cost consists of both fixed and variable components including:
Fixed Costs
Tooling and setup – One-time costs to prepare fabrication processes including:
-CAM programming software costs
-Cleaning and coating equipment
-Developing process instructions
-Testing process parameters
Engineering support – Labor for design reviews, documentation, reporting
Equipment depreciation – Amortizing capital investment in fabrication machines
Facilities overhead – Factory space and infrastructure expenses
Variable Costs
Materials – Base laminate, copper foil, soldermask, legend ink, etc. Higher performance materials increase costs.
Labor – Operator labor for production including loading boards in equipment. Higher complexity drives more touch labor.
Energy – Electricity, gases like nitrogen and compressed air used in production.
Consumables – Chemicals, drill bits, cleanup materials used in processes like etching.
Yield loss – Scrap due to defects must be built into the cost. Yield loss has significant impact on unit costs.
Layer Count Impact
Layer count greatly affects PCB fabrication pricing:
- Each additional conductive copper layer adds material cost
- More complex layer alignment and lamination process steps are required
- Drilling cost increases due to tighter tolerances
4 to 6 layer boards have approximately 30-50% higher fabrication cost than 2 layer boards. And costs continue increasing steeply beyond 6 layers due to complexity factors.
Board Size Effects
Larger boards require more materials and longer processing times driving higher cost:
- Larger boards utilize more of the laminate materials per board
- Exposing, imaging, and etching steps take longer per board
- Larger drill bits are needed for vias and holes
- More chemical processing solution is used
Panel utilization optimization through layout and breakout patterns maximizes material usage.
Line Width and Space
PCBs with higher layer counts often require thinner traces and spacing to route complex circuitry. This increases costs:
- Tight tolerances require more precise (and expensive) imaging and etching equipment
- More sophisticated soldermasks and legend printing ability are needed
- Tighter tolerances lead to lower yields as defect likelihood increases
- Multi-up panel design can help offset costs by maximizing batch size
Another option is post-etch plating to obtain finer trace/space after initial PCB fabrication.
Hole Size Effects
- Smaller drilled holes require more expensive carbide drill bits
- Tight hole tolerance necessitates precision drilling machines
- Additional steps of deburring small holes may be needed
- Plating chemistry costs increase for plating tiny vias and holes
Blind and buried vias also add cost over standard through-hole vias.
Via and Hole Density
Higher via and hole density drives cost through:
- More drilling time needed per board
- Potential stackup alignment challenges
- Additional laser drilling passes likely required
- Increased plating complexity for many blind/buried vias
Table: Sample Via Pricing
| Via Type | Price |
|---|---|
| Standard Through Via | $0.10 |
| Blind Via | $0.35 |
| Buried Via | $0.50 |
| Microvia | $0.90 |
Pad Geometries
Complex pad shapes require more sophisticated photolithographic patterning equipment and processes. Examples include:
- 6-10 mil pitch BGA fanout routing
- Dense QFN lands with 0.35mm pitch
- Mixed density pads requiring stepped stencils
- Non-rectangular pad shapes
Simpler rectangular SMT pads with larger pitch enable lower cost processes.
##Panel Utilization
Maximizing the number of boards laid out on fabrication panels reduces cost through:
- Less material wasted
- Batch processing
- Amortizing setup across boards
But productivity and yield should not be sacrificed through overly dense panel packing.
##Special Processing
Additional fabrication steps drive cost:
- Automated optical inspection (AOI)
- Impedance testing
- Special drill operations like CNC routing
- Thick copper boards above 3 oz.
- Backdrilling of PTHs
- Controlled depth drilling
- Teardropping open solder lands
Additive steps should have defined quality benefit.
Test and Inspection Requirements
Testing to IPC Class 2, Class 3, or higher increases cost through:
- Additional inspection steps like AOI
- Electrical testing labor and fixture expenses
- Manual manipulation time per board
- Record keeping for traceability
Table: Sample Testing Pricing
| Testing Type | Price |
|---|---|
| ICT Test | $0.75 per test |
| Functional Test | $1.25 per test |
| Flying Probe | $2.50 per test |
##Lead Time Requirements
Aggressive lead times incur additional costs:
- Expedited shipping of materials
- Disruption of batch optimization
- Increased need for WIP storage space
- Additional resources for split lot prioritization
- High mix short runs drive more changeovers
Reasonable lead times allow better manufacturing planning and efficiency.
##Location Specific Factors
Country specific factors also impact PCB pricing:
- Labor rates and facility costs
- Import duties and logistics
- Supply chain infrastructure maturity
- Economies of scale
- Environmental regulations
- Currency exchange rates
Qualifications and Certifications
Special qualifications like ISO, automotive, aerospace, medical add costs:
- Dedicated facilities and personnel
- More stringent processes and auditing
- Higher performance materials
- Extended record-keeping and traceability
There are likely few suppliers with accredited facilities, limiting competition.
Order Volume Pricing
Larger order volumes provide economies of scale through:
- Amortizing fixed costs over more boards
- Optimized batch sizes during production
- Volume component procurement discounts
- Lower cost shipping per board
Table: Volume Pricing Example
| Order Qty | Board Price |
|---|---|
| 1-50 | $50 |
| 50-100 | $45 |
| 100-500 | $40 |
| 500-1000 | $35 |
| 1000+ | $30 |
Summary of Cost Drivers
The key PCB cost drivers include:
- Layer count
- Board size
- Line width/space
- Hole size/density
- Pad geometries
- Panel utilization
- Special processing
- Test requirements
- Lead time
- Location
- Qualifications
- Order volume
Understanding cost drivers allows designers and engineers to make informed tradeoffs between board performance and cost during development.
Estimating PCB Assembly Costs
In addition to base fabrication expenses, fully assembled PCB pricing includes assembly process and component costs.
Assembly Processes
- Solder paste dispensing
- SMT pick and place machine programming and setup
- Reflow soldering
- Through-hole component insertion
- Manual and automated inspection
- Box build activities like cabling and fastening
- Functional testing and programming
Higher component densities require more advanced assembly equipment with smaller placements tolerances, driving cost.
Component Costs
The bill of materials (BOM) makeup largely determines assembly expenses:
- Component costs – passives vs ICs vs connectors
- Package sizes – 0402 vs 0508, QFP vs BGA
- Mix of through-hole and SMT parts
- Component sourcing – supplies vs consignment
- Densely populated boards require more inspection points
BOM cost reduction through component engineering and sourcing is key.
Estimating End PCB Cost
While full-turnkey estimates from assemblers provide the most accurate pricing, manufacturers can also roughly estimate total board cost using:
Bare Board Cost – Fabrication quote based on design files
Component Cost – Complete BOM list with up-to-date supplier pricing
Assembly Cost – Buildup from standard SMT, through-hole, and test process costs
Margin – Markup percentage
Local Taxes – Geographic sales taxes if applicable
Accurate costing ensures the end product is commercially viable and priced appropriately based on market factors.
Controlling PCB Costs
Methods to manage board costs include:
- Design optimization through DFM practices like panel utilization
- Standardized component packages and consolidation
- Modified layer counts, board thickness, finishes
- Market analysis for competitive fabrication and assembly pricing
- Value engineering alternate materials or processes
- Multi-sourcing and staged regional sourcing plans
- Customs optimization through bonded warehouses
Cost management should not compromise quality or manufacturability.
Conclusion
Determining true PCB pricing is a complex endeavor encompassing numerous fabrication, component, assembly, and logistics factors. Understanding the key cost drivers provides the ability to estimate and manage board costs through design tradeoffs, supplier selection, volume optimization, and global supply chain strategies. Keeping PCB cost in check without sacrificing quality requires expertise across the full electronics development, manufacturing, and distribution lifecycle.
How is PCB Price Calculated – FAQ
Q: What is the best way to get an accurate PCB cost estimate?
A: Getting budgetary quotes for fabrication + assembly from potential vendors using your actual design files and BOM will give the most accurate estimate.
Q: How much does it typically cost to fabricate a 2 layer vs. a 4 layer board?
A: As a rough estimate, 4 layer boards run about 30-50% higher cost than 2 layer. But many other factors like density impact cost too.
Q: What are some ways PCB design optimization can help reduce board costs?
A: Methods like maximizing panel utilization, standardizing hole sizes, optimizing layer counts, and simplifying line widths/spaces.
Q: Should PCB procurement focus primarily on finding the lowest cost supplier?
A: While cost is crucial, quality, reliability, and manufacturability for your specific design are also vital. The cheapest option may have hidden costs later if boards fail.
Q: How can manufacturers estimate component costs in PCB pricing?
A: Maintain an up-to-date BOM costed out from suppliers plus overhead/margin to roll up total component cost impact.
