Heat Sink Fabrications Guide
QUICK & EASY GUIDE TO CHOOSING A HEAT SINK
1
Heat Sink Reference Guide
www.boydcorp.com
September 2020
Boyd Heat Sink Fabrications Guide
A Quick & Easy Guide to Choosing a Heat Sink
Overview
Over several decades, Boyd has built the world’s largest portfolio of heat sinks and thermal management technologies.
We’ve utilized this experience and knowledge to develop our Heat Sink Reference Guide to help you find the right heat
sink solution. This article covers the most popular passive heat sink types, integrations, customizations and how to
choose the right fabrication and fin type for your application. Choosing the correct heat sink is essential to optimized
cooling, with higher performance in more compact geometries at the correct price point. Our quick reference guide will
help you to decide where to begin in building and choosing your heat sinks.
CONTENTS
Heat Sink Basics … 2
Quick Overview in Heat Sink Classification
Heat Sink Fabrications … 3
Stamped Board Level
Extrusions
Skived
Bonded Fin (& Brazed)
Zipper
Folded Fin
Die Cast
Additional Components … 9
Thermal Interface Materials
Fans & Blowers
Embedded Heat Pipes
Next Steps … 11
Get started finding your ideal heat sink.
Heat Sink Fabrications Guide
QUICK & EASY GUIDE TO CHOOSING A HEAT SINK
2
Heat Sink Reference Guide
www.boydcorp.com
September 2020
HEAT SINK BASICS
The heat sink is one of the most fundamental components in cooling electronic devices. For any heat source that cannot
be properly cooled through its own conduction cooling and needs more efficient cooling than a heat spreader, a heat
sink is necessary to move heat away from the source and dissipated through more optimized conduction or convection.
Heat sinks are primarily constructed with a base and fins. The
base is typically a planar surface that makes contact with the
heat source and spreads the heat from the hot spot to the fins.
Fins can be cut or constructed in any number of geometries
which often run perpendicular to the base to disperse heat. The
goal is to optimize the surface area of the heat sink so that the
most heat can be transferred and dissipated.
With rare exceptions, heat sinks are made of a thermally
conductive metal, the most common being Aluminum.
Aluminum has a thermal conductivity of 235 watts per Kelvin
per meter and is lightweight and inexpensive, making it ideal for
lighter, more cost-efficient heat sinks. Copper is also a popular
choice. Although copper is more expensive and heavier, it can
be necessary for high performing applications due to its high
thermal conductivity at 400 W/mK.
Finally, engineers often class heat sinks into “natural”
convection or “forced” convection. Natural convection (Passive)
heat sinks maximize surface area and conduct heat without the
addition of active components. Forced Convection (Active) heat
sinks are designed to utilize components such as fans and
blowers to force cooler air across the fins, creating turbulence
and increasing the cooling performance of the heat sink.
Basic heat spreaders are used in smaller applications
that emit very little heat and a heat sink is unnecessary.
Natural convection heat sink. Heat spreads across the
base and up the fins.
Force convection heat sink utilizing an impinged fan to
force air across the fins and create turbulence.
There are variations in fin density and length between convection types even when it is a
very similar construction.