Heat sink

Abstract

A heat sink is manufactured by forming a fin 2 for dissipating heat by separating a length of material from a substrate 1 while leaving the proximal end attached to the substrate 1. The fins are cut from the substrate by stamping process using the stamping single or progressive die tooling cutting the substrate 1 along dotted line 16. The heat sink is a unitary construction, with the fins 2 being integrally formed with the substrate 1.

Description

BACKGROUND TO THE INVENTION[0001] The present invention relates to heat sinks and to a method of forming the same. More particularly, but not exclusively, the present invention relates to an improved method of forming heat dissipating fins of a heat sink.[0002] Heat sinks are well known components used, for example, for dissipating heat from electronic circuitry, CPUs (computers) and microprocessors in order to cool the components to enable them to function consistently and properly. Heat sinks are often used in conjunction with printed circuit boards which are found in electronic equipment such as television sets and audio amplifiers. There are many types of conventional heat sinks.[0003] One of the most widely used heat sink is extruded heat sink. It is well know to manufacture the extruded heat sink by extruding aluminium, through a complex shaped die to produce a section. Extrusion limits, such as the fin height-to-gap and fin thickness, usually dictate the flexibility in design...

AI Technical Summary

Benefits of technology

[0007] It is another object of the present invention to provide an improved method of forming the fins to achieve maximum fin height-to-gap aspect ratio and to reduce the fin thickness to as thin as 0.2 mm. The improved method is less expensive, faster and more flexible, and which results in higher cooling capacity and more reliable heat sinks.

[0009] Such a method may allow a heat sink to be formed from a unitary sheet of material. The fins are an integral part of the substrate and therefore do not need to be attached to a base (As the folder type or U-fin heat sink does), so there are no joints which could reduce conduction of heat or deteriorate with rough handling and / or ageing. Fins may be produced by cutting thin lengths of material from the substrate.

[0011] The fin may extend generally perpendicularly to the plane of the substrate. This may be advantageous as it allows heat to escape from a plurality of fins as it rises between the fins.

[0014] The method may typically be used to form a plurality of the very fine fins up to 0.2 mm in thickness on the substrate. A plurality of fine fins that provide larger surface area expose to the air stream will provide improved heat dissipation.

[0015] The plurality of fins may be formed in a series of spaced apart rows. The space between the adjacent fins can be minimised to achieve the maximum fin height-to-gap aspect ratio (20 to 40) thus increase the surface area for better cooling capacity. The spacing apart of the rows may allow improved air circulation, which may also increase heat dissipation.

[0017] Each fin may be a single thin layer of material extending from the substrate. By forming the fins as single layers, no heat is trapped within a single fin, and heat dissipation may be improved.

Problems solved by technology

However, as the aspect ratio increases, the extrusion tolerance is compromised.

Also, extrusion equipment is expensive, the process slow, Further, in order that it can be made by an extrusion process, a heat sink must be made from aluminium, and other materials cannot be used.

One disadvantage of such an arrangement is that the corrugated sheet which forms the fins forms a heat trap between alternate pairs of fins.

Such an arrangement is disadvantageous in that the additional manufacturing step of applying the rivets is necessary, and further in that the rivets may work lose, reducing the effectiveness of the heat sink.

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