1 / 1
Famous Heavy Copper PCBs from China Suppliers - High Current Capacity & Excellent Heat Dissipation Factory Solutions Companies, Pricelist
Product Description
What is Heavy Copper PCB?
▶
The core is used in high-current and high-power scenarios (such as power supplies, new energy, industrial control, etc.). The key points of its design, manufacturing and application are as follows:
Core Features & Application Scenarios
⚡
Strong Current-Carrying Capacity
The current-carrying capacity of 70μm copper foil (2 oz) is approximately twice that of 35μm copper foil (1 oz) under the same line width.
🌡️
Good Heat Dissipation
The thick copper layer quickly conducts heat, reducing the risk of device overheating in demanding environments.
🔩
High Mechanical Strength
Thick copper enhances the PCB's resistance to bending and impact, extending service life.
🏭 Typical Applications
Power converters (AC-DC / DC-DC), BMS for new energy vehicles, industrial frequency converters, control boards for welding machines, and more.
Key Design Points
1 Selection of Copper Foil Thickness
| Specification | Thickness | Recommended Scenario |
|---|---|---|
| 2 oz | 70 μm | Large current circuits ≥ 5A |
| 3 oz | 105 μm | Medium-high power applications |
| 4 oz | 140 μm | High-power industrial use |
| 6–12 oz | 210–420 μm | Ultra-power scenarios ≥ 20A |
2 Trace & Current-Carrying Capacity Design
- Current-carrying capacity must be calculated combining copper thickness, line width, and temperature rise requirements (typically designed for a 10℃ temperature rise).
- Formula reference: I = K × W × T0.83 — where I = current, K = coefficient, W = line width, T = copper thickness.
- Example: 2 oz copper (70μm), wire width 5mm → current-carrying capacity ≈ 15A at 10℃ rise.
- Keep high-current traces as short and wide as possible; avoid narrow necks (sudden line width changes cause local overheating).
- Multi-layer boards can use parallel connection of multiple copper layers (e.g., 2 layers of 2 oz = 4 oz equivalent) to enhance current-carrying capacity.
3 Via & Pad Design
- Vias: For high-current vias, increase hole diameter (≥ 0.5mm), add more vias (estimate ~1A per hole), and ensure copper plating thickness on hole wall ≥ 20μm (vs. 8–12μm for standard PCBs).
- Pads: Thick copper pads should be enlarged (0.2–0.5mm larger than standard pads) to prevent heat dissipation during soldering from causing false soldering.
4 Heat Dissipation & Insulation Design
- Heat dissipation: The thick copper area can be designed as a "copper sheet heat sink", or a metallized via array (via spacing ≤ 1mm) can be added to connect to the heat dissipation layer.
- Insulation: Wire spacing for thick copper layers should be widened — for 70μm copper, the corresponding wire spacing should be ≥ 0.2mm to prevent creepage breakdown under high voltage.
Manufacturing Process Difficulties & Control
🔧 1. Copper Foil Lamination & Etching
Thick copper lamination: Requires high-temperature and high-pressure lamination (180℃ / 4MPa) to ensure peel strength between the copper foil and substrate (≥ 1.2N/mm).
Thick copper etching: Etching rate is slow (~1μm/min); etching time must be precisely controlled to avoid side etching (side etching amount ≤ 0.05mm). A stepwise etching process should be adopted to reduce line width deviation.
📐 2. Lamination & Warpage Control
The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from the substrate. During lamination, a "symmetrical structure" (consistent copper thickness between upper and lower layers) should be adopted, and a rigid support layer should be added to prevent PCB warping — warping degree must be ≤ 0.5%.
✨ 3. Surface Treatment
The surface of thick copper is prone to oxidation. It is preferred to choose tin plating (high-temperature tin layer) or nickel-gold plating to avoid OSP (incomplete organic film coverage).
The pad area needs to be enlarged with a "solder mask opening window" to ensure proper bonding force between the solder and thick copper.
Core Summary
The core of heavy copper PCBs is "high current-carrying capacity + heat dissipation". In terms of design, it is essential to match copper thickness with current-carrying capacity requirements. In manufacturing, challenges such as thick copper etching and lamination warping must be carefully resolved. Heavy copper PCBs are best suited for high-power, high-current industrial and energy scenarios.
Send Inquiry
Frequently Asked Questions (FAQ)
Q
What is the minimum copper thickness considered "heavy copper" in PCB manufacturing?
Generally, copper thickness of 2 oz (70μm) or above is considered heavy copper. Standard PCBs typically use 1 oz (35μm) copper foil. Heavy copper PCBs commonly range from 2 oz to 12 oz depending on the application's current and power requirements.
Q
How do I calculate the current-carrying capacity of a heavy copper trace?
The current-carrying capacity can be estimated using the formula: I = K × W × T0.83, where I is the current (A), K is a process coefficient, W is the trace width (mm), and T is the copper thickness (μm). For example, a 2 oz copper trace (70μm) with a 5mm width can carry approximately 15A at a 10℃ temperature rise.
Q
What are the main challenges in manufacturing heavy copper PCBs?
The three primary manufacturing challenges are: (1) Etching control — thick copper etches slowly and is prone to side etching, requiring a stepwise etching process; (2) Lamination warpage — the CTE mismatch between thick copper and substrate requires symmetrical layer design; and (3) Surface treatment — thick copper surfaces oxidize easily, making tin plating or nickel-gold plating the preferred finishing methods.
Q
What surface finishes are recommended for heavy copper PCBs?
For heavy copper PCBs, HASL (Hot Air Solder Leveling / tin plating) or ENIG (Electroless Nickel Immersion Gold / nickel-gold plating) are strongly recommended. OSP (Organic Solderability Preservative) is generally not ideal for heavy copper because the organic film may not fully cover the large copper surface areas, leading to oxidation issues.
Q
Which industries and products most commonly use heavy copper PCBs?
Heavy copper PCBs are widely used in: power electronics (AC-DC and DC-DC converters), new energy vehicles (Battery Management Systems / BMS), industrial automation (frequency converters, motor drives), welding equipment (welding machine control boards), and renewable energy (solar inverters, wind power systems) — any application requiring high current and efficient thermal management.
Q
Can multiple layers of standard copper replace a single heavy copper layer?
Yes. In multi-layer PCB designs, connecting multiple copper layers in parallel can effectively increase the current-carrying capacity. For example, two layers of 2 oz copper connected in parallel are electrically equivalent to a single 4 oz copper layer. This approach can be a practical solution when manufacturing constraints limit the use of very thick single copper layers.
