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Aluminium PCB (MCPCB): When Metal Core Beats FR-4

LED and power boards use a metal core for one reason: heat. Here is how to specify the stackup, finish and mechanical features so the board does what the thermal model promised.

Hitech Circuits Engineering Desk

Shenzhen, China · PCB fabrication and assembly

2 min read

Published:

Last updated:

Technical review: Process figures checked against our published capability sheet. View capability sheet

What a metal-core stackup looks like

A typical MCPCB is a single conductive layer on a dielectric layer bonded to an aluminium base. The dielectric is thin — often 0.05–0.2 mm — because its job is to conduct heat while standing off voltage. That thin dielectric is also why metal-core boards are usually single-sided: routing a second signal layer means adding another dielectric and copper, and the thermal benefit per layer drops.

Specify the thermal path, not just the material

  • Thermal vias move heat from a pad to the metal base; state their diameter, pitch and whether they are filled.
  • Copper thickness on the circuit layer affects spreading; 1–2 oz is common, and heavier copper helps where current density is high.
  • Solder mask must be specified for the finish you choose; white mask is common on LED boards but yellows under prolonged high temperature.

Mechanical details that decide yield

Metal boards are machined, not routed like thin FR-4. Specify the outline, V-score or routing tolerances, and whether the aluminium edge will be exposed. Remember that the metal base is conductive: mounting holes need clearance or insulating hardware, and the board edge should be deburred.

What we build

Our plant runs 1–38 layer FR-4 boards up to 580 × 1900 mm and 0.1–6.0 mm thick, and as an aluminum pcb manufacturer we also build aluminium, ceramic and high-frequency boards for thermal and RF work. Send the thermal requirement, the LED or power device footprint and the mechanical drawing; we will confirm the stackup and the finish before tooling.

Technical Specifications

Layer count
1–38 layers (FR-4); 1–2 layer typical for MCPCB
Board thickness
0.1–6.0 mm (FR-4)
Maximum board size
580 × 1900 mm

Frequently Asked Questions

  • When should a design use an aluminium board instead of FR-4?

    Use metal core when the thermal path matters more than signal density: LED arrays, power conversion and motor drivers where heat must leave the component through the board. For dense digital routing the lower dielectric constant of FR-4 and the ability to build many layers usually win.

  • Can aluminium boards carry plated through holes?

    Single-sided MCPCB usually avoids PTH because the aluminium base is conductive; connections are made with thermal vias or mechanical interfaces. If you need plated holes, the stackup must isolate the metal core and the design should be reviewed before tooling.

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