Thermal design often starts with a standard extrusion — until the layout no longer fits. A custom CNC machined heat sink offers full design freedom, but at a different cost structure. Here is how to decide.
Process Comparison
| Factor | CNC machined | Extruded | Extruded + machined |
|---|---|---|---|
| Tooling | None | Extrusion die | Die (or standard profile) |
| Fin geometry | Any accessible shape | Constant profile | Profile + pockets/holes |
| Best quantity | Prototype – low volume | High volume | Medium – high |
| Lead time | Short | Die adds time | Moderate |
| Material | 6061, 6063, copper | 6063 typical | 6063 |
When CNC Machining Wins
- Prototypes and small batches where a die is not justified
- Complex mounting pockets, bosses and cut-outs integrated into the heat sink
- Pin fins or varying fin heights
- Copper heat spreaders for compact high-power designs
When to Switch to Extrusion
Once your design is stable and annual volume grows, an extrusion die often reduces unit cost dramatically. A hybrid approach — extrude the fin profile and CNC machine pockets and holes — gives the best of both.
Finishing for Thermal Performance
Black anodizing improves radiative heat transfer in natural convection. Conductive chromate (chemical film) keeps contact surfaces electrically conductive. Flatness of the mounting surface is critical — specify it on the drawing.
Explore our CNC milled aluminum heat sink parts or send a drawing via request a quote.
Get a Quote for Your Parts
Send your drawing (PDF, STEP or DWG) with quantity, material and finish. An engineer from Zhufeng Precision will review it and reply within 24 hours.
FAQ
Is a machined heat sink better than an extruded one?
Not inherently. Machining offers design freedom for low volumes; extrusion is cheaper at high volumes.
Why are heat sinks anodized black?
Black anodizing increases emissivity, improving heat radiation especially in natural convection.
Can you machine copper heat sinks?
Yes. Copper conducts heat better than aluminum but is heavier and more expensive.