PCBMASTER Shares with You Which Is More Cost-Effective in IoT Product Development, HDI or Rigid-Flex PCB
Author: Jack Wang
With the rapid popularization of Internet of Things (IoT) devices, the design of electronic products is increasingly trending towards miniaturization, multi - functionality, and high reliability. As a core component of IoT devices, the choice of printed circuit boards (PCBs) directly affects the product's performance, cost, and market competitiveness. Among them, high - density interconnect (HDI) PCBs and rigid - flex PCBs have become popular options in IoT development due to their unique technical advantages. However, which solution is more cost - effective? This article will conduct an in - depth analysis from multiple dimensions such as design, manufacturing, and application scenarios to help developers make the optimal decision.
I. HDI PCB: Cost Advantages of Miniaturization and High Integration
1. Technical Features Matched with IoT Requirements
HDI PCBs achieve high - density wiring through technologies such as microvias and blind/buried vias. The line width/line pitch can be as low as 50μm/50μm, and the number of layers is usually 8 - 20. This structure is highly suitable for IoT devices that require miniaturization, such as smartwatches and medical sensors.
①Space - Saving: The high integration of HDI can reduce the PCB area by 30% - 50%, reducing the cost of the enclosure and overall materials.
②Signal Integrity: The short - path design reduces signal loss, making it suitable for high - frequency communication modules (such as 5G/Wi - Fi 6).
2. Cost Structure Analysis
Initial Cost: The laser drilling and special materials (such as low - loss substrates) of HDI result in a single - board cost that is 20% - 40% higher than that of ordinary PCBs.
Long - term Benefits:
①Reduced use of connectors and cables (saving 15% of the assembly cost).
②High reliability reduces the rework rate (a smart home case shows a 60% reduction in failure rate).
3. Applicable Scenarios
①High - Complexity Devices: Such as IoT gateways with AI edge computing.
②Mass Production: The marginal decrease in the single - board cost is significant after mass production.
II. Rigid - Flex PCB: Hidden Costs of Flexibility and Reliability
1. Technical Advantages and IoT Pain Points
Rigid - flex PCBs integrate rigid boards and flexible circuits, allowing for three - dimensional folding installation. Its core values are as follows:
①Mechanical Adaptability: Suitable for scenarios that require bending, such as wearable devices (such as foldable - screen bracelets) and industrial sensors.
②Reduced Connection Points: Eliminates traditional cables and connectors, reducing the assembly failure risk by 25%.
2. Hidden Cost Challenges
①Material Cost: The price of polyimide (PI) substrate is 3 - 5 times that of FR - 4.
②Process Complexity: Requires multiple - process lamination, and the yield rate is usually 10% - 15% lower than that of HDI.
③Design Verification Cost: The bending life test of the flexible part (such as 100,000 cycles) increases the development cycle.
3. Economic Break - even Point
①Small - batch, High - value Products: Such as military - grade IoT terminals, which can afford a higher unit price.
②Long - life - cycle Devices: Reduces maintenance costs (an industrial IoT device case shows a 18% reduction in total cost).
III. Cost Comparison: Key Decision - making Factors
Dimension | HDI PCB | Rigid - Flex PCB |
Initial Design Cost | High (requires special software and simulation) | Extremely high (3D structure verification) |
Single - board Manufacturing Cost | Medium - high (laser drilling costs) | High (materials + composite process) |
Assembly Cost | Low (high integration) | Extremely low (no connectors) |
Maintenance Cost | Low (high reliability) | Medium (flexible part is prone to fatigue) |
Applicable Quantity | Order qty > 10k is better | Order qty < 1k is better |
IV. Practical Cases: How to Choose the Optimal Solution?
Case 1: Smart Home Controller
Requirements: Supports Wi - Fi/Bluetooth/Zigbee, size <5cm², mass production of 50,000 units per month.
Choice: A 6 - layer HDI achieves full - function integration, and the total cost is 12% lower than that of an 8 - layer ordinary PCB.
Case 2: Wearable Health Monitor
Requirements: Arc - shaped to fit the wrist, resistant to 50,000 bends.
Choice: Although the single - board cost is 30% higher, it reduces the assembly man - hours by 40%.
V. Future Trends: Hybrid Technologies and Cost Optimization
With the development of technology, HDI rigid - flex PCBs (such as flexible circuits with HDI layers) are emerging. Such designs can achieve both high - density wiring and three - dimensional installation. Although the current cost is high, they have shown potential in high - end IoT devices (such as AR glasses).
Conclusion: Cost Savings Depend on Product Definition
Choose HDI: If miniaturization, high - frequency performance, and large - scale production are pursued.
Choose Rigid - Flex PCB: If mechanical flexibility or ultra - low assembly cost is required.
Hybrid Solution: For the high - end market, to balance performance and special structural requirements.
By accurately matching product requirements with technical characteristics, developers can reduce the total cost of ownership (TCO) by 15% - 30%, gaining a competitive edge in the red - ocean IoT market.
If you want to learn more, PCBMASTER welcomes your consultation at any time!
Author: Jack Wang