Heavy Copper Boards
Finished copper from 3oz to 20oz for high-current paths: extreme reliability for power modules, EV chargers and industrial drives.
What is a Heavy Copper Board
A PCB with finished copper thickness ≥ 3oz (105μm) is a heavy copper board, achieved by electroplating or thick copper foil - carrying hundreds of amps on limited board space, it is the backbone of power and new-energy boards.
| Copper Thickness | 3 - 20 oz finished copper |
| Conversion | 1 oz ≈ 35 μm, 20 oz ≈ 700 μm |
| Process | Electroplated copper build-up + differential etch compensation |
| Via Treatment | Resin plugging + electroplated capping |
| Quality Standard | IPC Class 3 optional, cross-section archive |
| Typical Uses | Power modules, OBC, charging piles, energy storage |
Choose Copper Weight by Current
Current capacity is determined by copper weight and trace width together. The figures below assume a 30℃ temperature rise - final rating subject to engineering review.
3 oz
Low-current power- Carries about 20A (10mm trace width)
- Suitable for standard power main loops
- Typical: inverters, converters
6-10 oz
Motor & automotive- Carries about 35-55A
- Resin plugging + capping for reliability
- Typical: motor drives, OBC
20 oz
Busbar grade- Carries about 90A and above
- Parallel vias share current and lower temperature
- Typical: ESS PCS, charging pile busbars
Current Carrying Reference
| Finished copper | Ref. current | Typical use |
|---|---|---|
| 2 oz | ~15 A | PSU main power path |
| 3 oz | ~20 A | Inverters / converters |
| 6 oz | ~35 A | Motor drives / chargers |
| 10 oz | ~55 A | Onboard charger (OBC) |
| 20 oz | ~90 A | ESS / charging pile busbar |
Process Challenges & Our Solutions
Severe etching undercut makes trace tolerance hard to hold
Differential etching with width compensation plus free Gerber review
High-current vias heat up and threaten long-term reliability
Resin plugging with copper capping and parallel via grouping
Lamination alignment and thickness tolerance are hard to keep
IPC Class 3 acceptance with cross-section archive for every batch
Product Showcase
Power Module Cases
6-Layer Servo Drive Heavy Copper Board
4-Layer Inverter Heavy Copper Board
8-Layer Charging Module Heavy Copper Board
4-Layer Welding Equipment Heavy Copper Board
EV / New Energy Cases
10-Layer Onboard Charger (OBC) Board
6-Layer Charging Pile Busbar Board
12-Layer ESS PCS Power Board
8-Layer Inverter Power Board
Manufacturing Capabilities
Standard manufacturing capability range for this product line. Contact our engineers to evaluate special requirements.
| Finished Copper | 3 - 20 oz |
| Layer Count | 2 - 12 layers |
| Min. Trace/Space | 10/10 mil (3oz) |
| Hybrid Stack-up | Heavy copper layers + standard signal layers |
| Via Plugging | Resin plugging + electroplated capping |
| Surface Finish | ENIG / HASL |
| Quality Standard | IPC Class 3 optional, cross-section archive |
| Electrical Test | 100% electrical test; four-wire testing for high-current points |
Lead Time & Pricing Highlights
Current without compromise
Up to 20oz Copper
Carries hundreds of amps on tight board space.
Better Thermal Rating
Thick copper spreads heat and reduces hot spots.
Class 3 Reliability
IPC Class 3 workmanship for automotive and industrial grade.
Typical Applications
EV Charging
Onboard chargers and charging pile power modules.
Power Modules
Inverters, converters and motor drives.
Industrial Drives
Servo drives and industrial power supplies.
New Energy
Photovoltaic and energy-storage power boards.
From Gerber to delivery in four steps
Upload Files
Send Gerber/ODB++ and stack-up table; standard boards get instant pricing.
Review & Quote
Complex boards get an engineer review before quoting.
Confirm Production
Confirm specs and price, pay online, and your boards enter the production queue.
Test & Deliver
Flying probe/fixture testing on every board with reports, shipped worldwide.
Further Reading
For more PCB process knowledge and technical practice, visit our blog center.
