最も一般的なヒートシンク構造とは？

Electronic components generate heat. When they overheat, they fail. So how can we keep them cool? Heat sinks are the answer—but not all heat sinks are created equal.

The most common heat sink structures include straight-fin, pin-fin, cross-cut, flared-fin, and heat pipe-integrated designs. Each structure handles airflow, space, and thermal loads differently.

Different designs work better under different conditions. If you want to improve your product’s cooling, you need to understand how these structures behave.

How do pin-fin and straight-fin designs differ?

Too hot to handle? Your cooling system may be the problem. Pin-fin and straight-fin heat sinks are everywhere—but which one is right for your device?

Pin-fin heat sinks offer multi-directional airflow and higher surface area density, while straight-fin designs allow lower pressure drop and directional airflow efficiency.

Pin-fin and straight-fin designs look very different, and they perform differently, too. Straight fins are long and parallel. They guide airflow in one direction, which works great when air moves in a straight line. Pin-fin heat sinks, on the other hand, use many small columns arranged on the base. This allows air to flow from multiple directions.

Comparison Table: Pin-Fin vs Straight-Fin

Pin-fin sinks often perform better in forced convection (fans), where more air pushes through. However, they have higher resistance. If you’re using passive cooling or low airflow, a straight-fin sink might be better. Also, straight fins are easy to make through extrusion, which keeps costs down.

Which heat sink structure suits compact spaces best?

Tight spaces, tight deadlines—thermal designers know the pain. What kind of heat sink works when there’s barely any room?

Pin-fin, zipper-fin, and heat pipe-based heat sinks are ideal for compact spaces, thanks to their efficiency and ability to work under tight airflow constraints.

Compact designs require heat sinks that pack a lot of surface area into a small volume. That’s not easy. Standard extruded fins may not fit or cool effectively. Pin-fin structures are often ideal here. They allow airflow from many angles and pack lots of cooling surface.

Compact-Friendly Heat Sink Structures

If height is the issue, heat pipes let you move heat away from the source, then cool it somewhere roomier. Folded or zipper fins squeeze more cooling area into the same volume by layering fins tightly.

Every millimeter matters in compact designs. That’s why engineers love flexible layouts like pin-fins and heat pipe hybrids.

Why are heat pipes used in modern heat sinks?

You’ve probably seen copper heat pipes on CPUs or graphics cards. Why are they so common now?

Heat pipes are used because they spread heat fast, reduce hot spots, and allow fins to be placed farther from the heat source. They improve cooling without increasing size.

A heat pipe is a sealed tube filled with a small amount of liquid. When one end gets hot, the liquid inside evaporates. The vapor travels to the cooler end, where it condenses. This cycle transfers heat quickly across the pipe.

Why Heat Pipes Make Sense

• Super-high thermal conductivity: Better than solid copper.
• Spreads heat across large fin areas: Prevents hot spots.
• 可動部がない: Passive and reliable.
• Compact: Routes heat in tight designs.
• Orientation-friendly: Works in most angles, especially with wick structure.

Today, many high-performance heat sinks combine base plates with heat pipes and fin arrays. This hybrid method gives you both good conduction (via the pipe) and strong convection (via the fins).

For example, in laptops or compact PCs, heat pipes carry heat to side-mounted or top-mounted fins. That keeps the internal layout clean and efficient.

What are the advantages of cross-cut fin designs?

Fins are long, right? But what if you cut them? Believe it or not, that can help. Cross-cut fins are designed to break airflow patterns—in a good way.

Cross-cut fin structures improve heat transfer by breaking boundary layers and allowing more airflow paths, especially deep in the fin array.

In a straight-fin design, air flows through channels between the fins. But inside those channels, the air slows down. The deeper you go, the less cooling occurs. Cross-cutting the fins solves that.

How Cross-Cuts Improve Cooling

• Disrupt stagnant air: Cuts break boundary layers.
• Shorten conduction paths: Each fin segment is more efficient.
• Enable multi-directional air access: Helps in turbulent or partial airflow.
• Improve low-speed airflow performance: More paths for air to escape and enter.

However, this comes with a trade-off. Cross-cuts can slightly increase airflow resistance, and too many cuts reduce fin strength or thermal mass.

Table: Cross-Cut vs Standard Fins

You can think of cross-cuts as the best of both worlds—easy to manufacture like straight fins, but with performance closer to pin-fins.

結論

Different heat sink structures offer different thermal benefits. Pin-fins, heat pipes, cross-cuts, and compact fins each play a role. Choosing the right one depends on airflow, space, and thermal load.