POWER ONLY
Mixed copper multilayer
Heavy copper on power layers, standard copper on control and signal layers in one stackup.
ConvertersDrives
3–10 OZ FINISHED COPPER
Heavy Copper PCB Manufacturer for High-Current Power Boards
APTPCB builds heavy copper PCBs with 3–10 oz finished copper for power supplies, motor drives, inverters and EV charging hardware. Send the current map and temperature-rise budget; engineering checks copper weight, spacing, lamination and assembly before the order is released.
- 3–10 oz finished copper
- Copper sized to current and temperature rise
- Mixed heavy and standard copper layers
- Assembly profile reviewed with the board
Get an Instant Quote
When do you need a heavy copper PCB?
Use heavy copper (3 oz / 105 µm finished copper or more) when a trace on standard 1–2 oz copper would have to be too wide to fit, or when a board replaces wiring or a bus bar. Thicker copper carries the same current in a narrower trace, spreads heat from power parts, and holds up better at plated holes and connector pins.
The price is in fabrication: thick copper needs etch compensation, wider spacing, resin-rich lamination and slower drilling. Those limits are listed by copper weight on the heavy copper PCB capabilities page (trace/space, annular ring and lamination rules), so you can check a layout before asking for a quote.
COPPER WEIGHT VS CURRENT
How much current can a heavy copper trace carry?
It depends on width, copper weight, allowed temperature rise and how well the board spreads heat. The widths below are external traces on a 1.6 mm FR-4 board at 25 °C ambient, no airflow, for a 20 °C rise, taken from our IPC-2152 heavy copper sizing guide. Use them to pick a starting copper weight, then confirm with IPC-2152 for your stackup.
- 20 A: about 3.2 mm on 3 oz, 2.3 mm on 4 oz, 1.5 mm on 6 oz, 0.85 mm on 10 oz.
- 40 A: about 8.4 mm on 3 oz, 6.1 mm on 4 oz, 3.9 mm on 6 oz, 2.1 mm on 10 oz.
- 60 A: about 14.2 mm on 3 oz, 10.4 mm on 4 oz, 6.6 mm on 6 oz, 3.6 mm on 10 oz.
- 100 A: 3 oz is not recommended; about 20.5 mm on 4 oz, 12.8 mm on 6 oz, 7.0 mm on 10 oz.
- A nearby internal plane can reduce the required width; a hotter ambient or a tighter rise budget increases it.
RFQ CHECKLIST
What do you need to send for a heavy copper PCB quote?
State finished copper per layer, not starting foil. Most heavy copper quotes stall on that one point.
- Files: Gerber or ODB++, drill file, fabrication drawing with revision, stackup and quantity.
- Copper: finished copper weight on every layer, and which nets need it (power only, or full layers).
- Current and heat: continuous and peak current on the main paths, allowed temperature rise, ambient and cooling.
- Voltage: working voltage, creepage and clearance, and any hipot requirement.
- Mechanics: press-fit or bolted terminals, bus bar or coin inserts, board thickness and flatness limits.
- Assembly and records: through-hole parts, soldering method, inspection class and the reports you need with each lot.
WHY APTPCB
Why order heavy copper PCBs from APTPCB?
Engineering checks copper weight against your current and spacing before anything is quoted as final, so you do not pay for 10 oz where 4 oz on the power layers does the job. Mixed constructions, with heavy copper on power layers and standard copper on signal layers, are reviewed as one stackup.
Board fabrication and assembly are quoted together when you need them. Heavy copper boards absorb a lot of soldering heat, so the reflow and selective soldering profile for thick copper through-hole joints is planned with the stackup, not after the boards arrive.
CONSTRUCTIONS
Heavy copper PCB constructions we quote
The construction is chosen from where the current flows and how the board is mounted.
POWER ONLY
HIGH CURRENT
LOCAL HEAT
COPPER WEIGHT MATRIX
Which copper weight should you specify: 3 oz, 4 oz, 6 oz or 10 oz?
Pick the lightest copper that meets current and temperature rise. Every step up widens the minimum spacing and adds fabrication cost.
3–4 oz: the usual starting point
FitsPower supplies, converters, 20–60 A paths
Min trace / space10/10 mil (3 oz); 12/12 mil (4 oz)
Signal routingFine-pitch parts possible on lighter layers
Cost impactLowest of the heavy copper range
6 oz: high-current power stages
FitsMotor drives, inverters, battery systems
Min trace / space18/18 mil
Watch forResin fill between thick traces, drill wear
Cost impactExtra plating and lamination control
8–10 oz: bus bar replacement
FitsPaths near 100 A, wiring or bus bar replacement
Min trace / space22/24 mil (8 oz); 22/25 mil (10 oz)
Watch forBoard flatness, solder fill on through-holes
Cost impactHighest; consider copper only on power layers
Before choosing more copper
If the heat comes from a few parts rather than the current path, a metal core or copper coin may solve it for less. See the high thermal conductivity PCB guide for the comparison.
QUALITY RECORDS
How is a heavy copper PCB checked before it ships?
Thick copper failures show up at resin fill, hole walls and finished copper thickness, so that is where inspection is focused.
IPC-6012: rigid board performance (Class 2 or 3 as specified)IPC-A-600: acceptabilityIPC-2152: current-carrying capacity
Finished copper
Copper thickness confirmed by microsection against the weight on the drawing.
Lamination
Resin fill between thick traces checked for voids before the lot moves on.
Electrical
Netlist test on every board; hipot where the RFQ calls for it.
Where heavy copper PCBs are used
Each of these puts high current through the board itself.
Power supplies and converters
AC-DC and DC-DC stages where copper weight sets trace width and heat.
EV charging and battery systems
Chargers, BMS and power distribution with long high-current paths.
Motor drives and inverters
IGBT and MOSFET stages with through-hole power terminals.
Solar and energy storage
Inverters and combiner boards; see the power and energy PCB page for the full board mix.
COST
What makes a heavy copper PCB cost more?
Copper weight is only part of it. These are the items that move the quote.
Quality
Records you can ask for
Per lot
- MicrosectionFinished copper and plating
- Electrical testNetlist, every board
- HipotWhen specified
- CoCWith each shipment
Cost
Heavy copper cost drivers
Fabrication
- Copper weightPer layer
- Layers with heavy copperMore layers, more cost
- DrillingSlower through thick copper
- InsertsCoins and bus bars add steps
Cost
How to lower heavy copper cost
Design
- Power layers onlyStandard copper elsewhere
- Copper weightLightest that meets rise
- SpacingDesign to the table, not the minimum
- PanelStandard sizes and drills
Heavy copper PCB manufacturer FAQ
Questions buyers and power engineers ask before ordering.
Get your heavy copper PCB quoted with the copper weight checked
Upload the fabrication package with current paths and temperature-rise targets. Engineering confirms copper weight per layer, spacing, lamination and assembly before pricing.
- Copper weight checked against current
- DFM on spacing, drilling and resin fill
- Board and assembly quoted together if needed