The present invention relates to a method for manufacturing a heat sink, and more particularly to a method for manufacturing a phase change type heat sink.
As computer technology continues to advance, electronic components such as central processing units (CPUs) of computers are being made to provide faster operational speeds and greater functional capabilities. When a CPU operates at a high speed in a computer enclosure, its temperature usually increases enormously. It is therefore desirable to dissipate the generated heat of the CPU quickly before damage is caused.
Conventionally, a heat sink is used to dissipate heat generated by a CPU. A conventional heat sink comprises a base contacting with the CPU and a plurality of fins attached to the base. The heat sink dissipates heat by conduction. However, as the heat generated by the CPU and other electronic devices continues to increase, the conventional heat sink can not meet its heat dissipating requirements any longer. Thus, phase change type heat sinks have gradually begun to replace the conventional heat sink.
A phase change type heat sink has an evacuated cavity and a quantity of working fluid sealed in the cavity. The phase change type heat sink transfers heat via phase transition of the working fluid. Thus, the phase change type heat sink has good heat conductivity and can quickly transfer heat from one place to another place.
Referring to
The cover 14 and the fins 20 are usually connected via welding, as a result, an interface heat resistance is formed between the cover 14 and the fins 20, which degrades the heat conduction from the cover 14 to the fins 20. Furthermore, the high temperatures used in welding can damage the capillary structure and hermetical effectiveness of the phase change type heat sink. These possible damages can result in the functional reliability of the phase change type heat sink being weakened and the useful life of the phase change type heat sink being shortened.
A method for manufacturing a phase change type heat sink, comprises the following steps: (1) offering a workpiece as parent material and fixing it; (2) performing a cutting (i.e., skiving) operation on an surface of the workpiece to form a cover integrated with a group of fins; (3) offering a tank with a cavity inside thereof and a quantity of working fluid and a capillary structure contained in the cavity; (4) welding the cover and the tank together to seal the cavity to thereby achieve a phase change type heat sink.
Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
Many aspects of the present method can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views
A method for manufacturing the phase change type heat sink 50 as described above comprises following steps as shown in
Step (1) offering a plane workpiece 300 as parent material and fixing it on an upper surface of a fixture 400. The plane workpiece 300 is made of a heat conductive material such as copper or aluminum. Preferably, the upper surface of the plane workpiece 300 is horizontal for facilitating cutting (i.e., skiving) operation in the next step. The fixture 400 has a slanted surface (not labeled) to support the work piece 300.
Step (2) performing a cutting (i.e., skiving) operation on an upper surface of the plane workpiece 300 by using a wedge-shaped cutting tool 500 moving back and forth in a line on the upper surface of the plane workpiece 300 to form the fins 210; then cutting off an unprocessed portion of the workpiece 300, whereby the cover 200 with fins 210 integrally formed is finished. The fins 210 formed in this operation may be lightly curving, a straightening step may directly go after this step to straighten the fins 210 perpendicular to the unprocessed workpiece 300.
Step (3) offering a tank 100 with a cavity 110 inside thereof. A quantity of working fluid is contained in the cavity 110 and a wick structure is formed on an inner surface of the cavity 110.
Step (4) welding the cover 200 and the tank 100 together to seal the cavity 110 to thereby achieve a phase change type heat sink 50.
Additionally, the wick structure in the cavity 110 can be omitted; in this case, the condensed working fluid flows back to a bottom of the cavity 110 by gravity. In addition, after Step (4), a vacuuming operation is applied to the cavity 110 to pump out air therein so that the tank 100 is vacuumed.
As shown in
The phase change type heat sink 50a can be manufactured in a quite similar method to that described above. The small difference is in step (2): after forming the fins 210a, the step (2) further comprises a step where the plane workpiece 300 is horizontally moved a predetermined distance relative to the cutting tool 500 to form the channel 220, then the cutting operation continues to form a neighboring group of fins 210b of the fins 210a. Furthermore, the cutting tool 500 and the feed rate control the thickness and the interval of adjacent fins 210a (or 210b).
The method utilizes the cutting (i.e., skiving) technology to cutting out a plurality of fins 210 (210a, 210b) on the upper surface of the plane workpiece 300 to form the cover 200 (200a). The fins 210 (210a, 210b) and the cover 200 (200a) are formed from a one-piece stock of the plane workpiece 300; thus, there is no interface heat resistance therebetween. The cutting technology has a fast processing capability and produces thin fins, which means that fin density of the fins 210 (210a, 210b) on the outer surface of the cover 200 (200a) can be increased. Furthermore, according to the preferred embodiment, the welding operation for mounting fins on a cover used in conventional method is avoided, whereby the possible damage to the cover 200 (200a) by the high temperature of the welding can be avoided in the preferred embodiment. Thus, the functional reliability of the phase change type heat sink 50 (50a) can be improved and the useful life of the phase change type heat sink 50 (50a) can be extended.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.