Heat Sink Technical Information
Heat sinks are devices that enhance heat dissipation from a hot surface to cooler ambient fluids, usually air. A heat sink does this by increasing the surface area that is in contact with the cooling fluid.
Aluminum extrusions are the most cost effective solution for cooling a majority of electronic devices. The versatility of the aluminum extrusion process allows for a wide variety of geometric configurations. Extrusion die tooling is also relatively inexpensive when compared to many other forms of tooling. Our engineering staff is prepared to assist you with your design to help reduce cost and improve extrudability.
| Thermal Properties | Metric | English | Comments |
| Heat Capacity | 0.9 J/g-°C | 0.214 BTU/lb-°F | |
| Thermal Conductivity | 208 @/m-K | 1450 BTU/in/hr-ft²-°F | |
| Melting Point | 616°C | 1140°F | Solidus |
| Liquidus | 654°C | 1210°F | |
| CTE, Linear 20°C | 23.4 µm/m-°C | 13 µm/in-°F | 20-100°C |
| CTE, Linear 250°C | 25.6 µm/m-°C | 14.2 µm/in-°F | Average over the range 20-300°C |
| Physical Properties | Metric | English | Comments |
| Density | 2.7 g/cc | 0.0975 lb/in³ | |
| Mechanical Properties | Metric | English | Comments |
| Hardness, Brinell | 60 | 60 | 500 kg load with 10mm ball |
| Harndness, Knoop | 83 | 83 | Converted from Brinell Hardness Value |
| Hardness, Vickers | 70 | 70 | Converted from Briness Hardness Value |
| Tensile Strength, Ultimate | 185 MPa | 26800 psi | |
| Tensile Strength, Yield | 145 Mpa | 21000 psi | |
| Elongation @ break | 12% | 12% | In 5cm: Sample 1.6mm thick |
| Modulus of Elasticity | 69 GPa | 10000 psi | Average of Tension and Compression. In aluminum alloys, the compresive modulus is typically 2% greater than the tensile modulus. |
| Poisson’s Ratio | 0.33 | 0.33 | |
| Fatigue Strength | 60 MPa | 10200 psi | 500,000,000 Cycles |
| Shear Modulus | 25.8 GPa | 3740 psi | |
| Shear Strength | 115 MPa | 16700 psi | |
| Electrical Properties | Metric | English | Comments |
| Electrical Resisitvity | 0.0000031 ohm-cm | 0.0000031 ohm-cm | |
| * Source: MatWeb.com, the Online Materials Database | |||
| Further information on aluminum alloy properties may be found at MatWeb website. | |||
M&M Metals extrusions comply with industry standard tolerances established by the Aluminum Association, Inc. Tolerances are directly related to the extruded shape: the larger the shape the greater the tolerance will be. In many cases, we can maintain ½ of the industry standard on one or two particular features. For full information of industry tolerances consult the Aluminum Association, Inc. website at www.aluminum.org.
Price Reduction Ideas
1. To keep burrs and shavings to a minimum on holes, locate holes between fins.
2. For larger quantity orders (500+ parts lot size with an annual usage of 2,500+ parts) design hole locations to fall between fins so that they can be punched, not drilled.
- Keep material thickness under 0.250″.
- Keep hole diameter greater or than or equal to material thickness.
- Keep the edge of the hole at least 1.5 times the hole diameter from the edge of the part and/or at least .020 in from the nearest fin.
3. Keep fin thickness greater than .032″.
4. Keep extruded base flatness to .004 in/in 9standard extrusion flatness tolerance). Pats can be machined to within .001 in/in.
5. Keep surface roughness to √ 125
The following guidelines apply to custom extruded heat sinks:
(These will help keep the die cost down and increase design extrudability)
Extrusions
The following guidelines apply to custom extrusions:
(These will help keep the die cost down and increase design extrudability)
Resources
Standards Organizations
American National Standards Institute
ASTM International
Best Manufacturing Standards
International Organizations for Standardization
ASTM International
Other Sites of Interest
The Aluminum Association
The Bergquist Company – Thermal Interface Materials
Fujipoly – Electronic Packaging
GrafTech International – Carbon and Graphite Solutions
Laird Technologies – Thermal Interface Solutions
MatWeb – Your Source for Materials Information
Parker Comerics – EMI Shielding and Thermal Interface Solutions
Saint-Gobain – Performance Plastics
