Key Differences Between Plated Through Holes (PTH) and Non-Plated Holes in PCB Design

Summary For industrial equipment and automation product manufacturers, choosing between Plated Through Holes (PTH, commonly called “plated holes”) and Non-Plated Holes (often referred to as “mounting holes”) is more than a design detail—it impacts circuit reliability, manufacturing costs, and component compatibility. Using the wrong hole type can lead to 20% higher rework rates or field failures in industrial environments (e.g., sensor modules, control boards). This guide breaks down their core differences, use cases, and how FUMAX optimizes hole selection for industrial PCBA needs.

In PCB design, holes serve two critical roles: enabling electrical connections between layers or providing physical mounting for components. Yet many procurement engineers and design teams confuse Plated Through Holes (PTH) with Non-Plated Holes—two distinct types with unique purposes. At FUMAX (www.fumaxtech.com), we clarify this distinction daily for industrial clients, ensuring their PCBs meet the rigorous demands of automation, robotics, and industrial control systems. Let’s dive into the key differences.

PTH

1. Core Definition: Conductivity vs. Physical Function

The fundamental difference lies in their primary purpose and construction:

Plated Through Holes (PTH): The “Electrical Connectors”

Plated Through Holes (PTH) are holes drilled through the PCB, with their walls coated in a thin layer of copper (via electroplating or electroless plating). This metal layer creates a conductive path between PCB layers.

• Key Trait: Conductive by design—current flows seamlessly from top to bottom layers or between inner layers.
• FUMAX Insight: We use 18–35μm copper plating thickness for industrial PCBs, ensuring compatibility with high-current applications (e.g., 5A+ power circuits in motor controllers).

Non-Plated Holes: The “Mechanical Anchors”

Non-Plated Holes (often called “non-conducting holes” or “mounting holes”) are drilled through the PCB without any metal coating on the hole walls. They serve strictly mechanical functions, not electrical ones.

• Key Trait: Non-conductive—no current passes through the hole itself.
• FUMAX Insight: We specify non-plated holes with tight tolerances (±0.1mm) for industrial enclosures, ensuring secure mounting of PCBs in vibration-prone environments (e.g., factory floors).

2. Critical Differences: Design, Cost, and Performance

Aspect	Plated Through Holes (PTH)	Non-Plated Holes
Conductivity	Conductive (copper-plated walls)	Non-conductive (bare substrate walls)
Manufacturing	Complex (drilling + plating + quality checks)	Simple (drilling only)
Cost	30–50% higher than non-plated holes (plating adds cost)	More cost-effective for mechanical use
Layer Compatibility	Ideal for multi-layer PCBs (2–20+ layers)	Used in single/double-layer PCBs or mounting
Current Capacity	Handles up to 10A+ (depending on hole size/plating)	No current-carrying capability

2.1 Manufacturing Complexity & Cost

PTH requires additional plating steps (electroplating or electroless copper deposition) and strict quality control (e.g., checking for plating uniformity to avoid open circuits). This adds 30–50% to the hole-related manufacturing cost compared to non-plated holes.

For industrial clients, FUMAX balances cost and performance: we recommend PTH only when electrical connectivity is needed, and non-plated holes for mounting—saving one automation client 15% on their 10k-unit PCB order by optimizing hole types.

2.2 Reliability for Industrial Environments

Industrial PCBs face extreme conditions (temperature cycles, vibration, high current), making hole selection critical:

• PTH Reliability: The copper plating creates robust interlayer connections that resist thermal stress (e.g., -40℃ to +125℃ for automotive or outdoor industrial use). FUMAX uses X-ray inspection to verify plating integrity, reducing layer-to-layer connection failures by 90%.
• Non-Plated Reliability: For mounting, we specify non-plated holes with chamfered edges to prevent PCB cracking during screw tightening—critical for PCBs in high-vibration industrial machinery.

3. Industrial Use Cases: When to Choose Each

Selecting the right hole type depends on your application’s electrical and mechanical needs:

Metalization 1

When to Use Plated Through Holes (PTH)

• Multi-layer PCB Interconnections: Essential for connecting inner layers in complex industrial PCBs (e.g., 8-layer control boards for robotics).
• Through-Hole Component Mounting: Used for插件式 (through-hole) components (e.g., DIP ICs, power connectors) where the component leads are soldered to the plated hole, creating both mechanical and electrical connections.
• High-Current Paths: Ideal for power circuits in industrial power supplies (e.g., 3A+ current paths in PLCs), where the copper plating ensures low resistance and heat dissipation.

FUMAX Case: For a client’s industrial sensor module (4-layer PCB), we used PTH for interlayer signal connections and power paths, reducing signal loss by 15% compared to a non-plated alternative.

When to Use Non-Plated Holes

• PCB Mounting: Securing the PCB to enclosures or chassis (e.g., M3/M4 screw holes in industrial control panels).
• Component Alignment: Guiding through-hole components during assembly (e.g., alignment pins for large connectors).
• Heat Dissipation Vents: In high-temperature industrial applications (e.g., power amplifiers), non-plated holes act as vents to reduce PCB temperature by up to 10℃.

FUMAX Case: A robotic arm controller required 6 non-plated mounting holes with 2.5mm diameter—we added chamfers and specified a 0.1mm tolerance to ensure compatibility with the client’s enclosure, eliminating assembly delays.

4. FUMAX’s Expertise in Hole Optimization for Industrial PCBs

Industrial PCBs demand precision in hole selection—one wrong choice can lead to costly downtime. Our approach includes:

1. Custom Hole Selection: We review your schematic and BOM to recommend PTH for electrical needs and non-plated holes for mechanical use, aligning with your industrial application’s requirements (e.g., vibration resistance, current capacity).
2. Quality Control: For PTH, we use automated optical inspection (AOI) and X-ray testing to ensure uniform plating—critical for industrial PCBs with long service lives (5+ years).
3. Cost Optimization: We balance plating costs with performance, avoiding over-specifying PTH (e.g., using non-plated holes for mounting to cut costs without compromising reliability).
4. Design for Manufacturability (DFM): Our free DFM checks flag potential issues (e.g., non-plated holes too close to conductive traces) before production, reducing rework rates to <1%.

Conclusion

Plated Through Holes (PTH) and Non-Plated Holes serve distinct, non-interchangeable roles in PCB design. PTH enables reliable electrical connections for multi-layer industrial PCBs, while non-plated holes provide cost-effective mechanical mounting. For industrial equipment manufacturers, choosing the right type is critical to avoiding field failures and controlling costs.

At FUMAX, we don’t just manufacture PCBs—we optimize every detail, including hole selection, to meet the rigorous demands of industrial automation. Whether you’re designing a sensor module, control board, or power supply, our team ensures your PCBs use the right hole types for performance and durability.

Ready to optimize your PCB design with expert hole selection? Contact FUMAX today at sales10@fumaxtech.com for a free DFM consultation. We’ll review your design, recommend the ideal hole types, and provide a detailed quote tailored to your industrial PCBA needs.