custom heat sink fabrication - manufacture of heatsinks

Pages written in Adobe 5.0.

You will need Adobe 4.0 reader to open.

If you do not have this version

download it here.

Custom Aluminum and Copper Heat Sink Fabrication

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.

The most common alloy for heat sinks is 6063-T5. This alloy is easy to extrude and has very good thermal and mechanical

properties. The following table lists some common properties of 6063-T5*:

Thermal Properties	Metric	English	Comments
Heat Capacity	0.9 J/g-°C	0.215 BTU/lb-°F
Thermal Conductivity	209 W/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
Hardness, Knoop	83	83	Converted from Brinell Hardness Value
Hardness, Vickers	70	70	Converted from Brinell 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 compressive modulus is typically 2% greater than the tensile modulus.
Poisson's Ratio	0.33	0.33
Fatigue Strength	70 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 Resistivity	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 size of 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 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 (standard extrusion flatness tolerance). Parts can be machined to within .001 in/in

5. Keep surface roughness to .

The following guidelines apply to custom extruded heat sinks:

(These will help keep the die cost down and increase design extrudability)

figure 1	figure 2
Use fin height to spacing ration less than 8:1 (Y/X) for ease of extrusion	Preferred Putting a radius on fins and base makes extruding easier.		Not Recommended Not putting radius on fins and base can cause die to crack.


To improve extrudability, have a 60° opening for screw bosses.	To ensure that extrusion will fill properly and die won't break , avoid small fins surrounded by large fins.		For threaded hardware, use serrated extruded slots.	To save machining, use straight slots for PC boards


Preferred Not Recommended Large hollow spots require sufficient die attachment metal to keep hollow from breaking off in die and to allow even flow.		A proven method to mate two pieces of extrusion.

Extrusion Size Limits:

We can extrude up to a 15.0" wide heat sink extrusion.

Heat sinks wider than 15.0" can be manufactured using our weld-assembly process.