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Tube type X-COOLER for microprocessors produced by metal injection moulding (MIM) technology
Feature article: PIM International, Vol.2 No. 1 March 2008, pages 51-54, 2128 words
FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan-Strasse 2, 2700 Wiener Neustadt, Austria
Abstract
Demand for better CPU coolers is rising continuously in parallel to the speed and reliability of microprocessors, following the motto 'faster, better, cheaper'. Microprocessor dissipation heat increases, lowering the thermal conductance of metal coolers and cooling power and thus increasing the failure rate, breakdown and burning of the device. The need for higher cooling power, exeeding the thermal limits of the classical metal coolers led to the development of new very complex cooler geometries that cannot be produced by powder die pressing or mould casting. A tube X-type cooler, consisting of thin tubes placed in a squared matrix bundle and shaped from Cu powder by MIM technology was developed to respond to the increasing demands for higher cooling rates. The main parameters of the injection, debinding and sintering processes were investigated, and the structure of Cu-powder, green (as injected) part, debinded (brown) part and sintered part as obtained by metallography and SEM, respectively, are given.
Introduction
Metal injection moulding technology today has been adopted as a technology of choice for producing complex shaped parts with high production rates, reproducible high tolerances with less finishing work, wide range of available materials, low labour costs and minimal scrap losses [1]. The disadvantages of MIM technology are: high cost of starting powder and feedstock, expensive equipment (PIM machine and mould complexity), possible high running costs, and complexity of the part design with the moulding in mind. For smaller series and prototypes, some other technologies such as RP (Rapid Prototyping) technology or classical casting, cutting, deformation, etc. are much cheaper and give results in a short time, but for large numbers PIM is definitely at an advantage [2], [3].
The prototype of X-COOLER fits all production requirements (technical and economic) demanded by metal injection moulding technology. It was a great challenge for metal injection moulding technology to produce the tube type CPU X-COOLER using pure Cu. This part consists of a bundle of thin tubes arranged in a matrix on the square Cu carrier plate as the motherboard. This heat sink shape with small and long tubes used instead of pins is patented by Fotec, Wiener Neustadt, Austria [4]. The development work started in 2003, and the following year led to a successful solution for producing the X-COOLER by metal injection moulding technology. ......
Further sections of this article include:
- The optimal processor cooling criteria
- Injection Moulding
- Debinding and sintering treatment
- Properties of the tube type MIM X-COOLER
- Conclusion
Figures and Tables:Fig. 1 CPU heat sink shaped by MIM Cu (pure copper): base plate area 50 x 50 mm2, height 30 mm, 96 'tubes' with wall thickness 0.3 mm Fig. 2 SEM micrograph of Cu powder Fig. 3 Copper feedstock granules, size of about 3.5mm Fig. 4 Ejection of the green part of X-COOLER (Cu feedstock) from the mould Fig. 5 Green part of tube type X-COOLER shaped by MIM technology Fig. 6 SEM fractographs of MIM Cu X-COOLER (heat sink) magnified ×3000: MIM green part (a), MIM de-binded (brown) part (b), MIM sintered part (c) Fig. 7 Microstructure of sintered parts (a) polished surface (b) Polished and etched surface (Cu-grains, boundaries and pores) Table 1 Copper powder specification [7] Table 2 Copper feedstock specification [7], [8] Table 3 Metal injection moulding (MIM) parameters of the FOTEC’s tube type X-COOLER Table 4 Cu MIM samples sintered in hydrogen Table 5 The main properties of FOTEC’s tube type X-COOLER |
__________________________________ Also available from PIM International: Cooling performance of tube X-COOLER shaped by MIM technology Micro-channelled heat exchanger manufactured by Ceramic Injection Moulding and co-firing (PDF Store) Metal and ceramic injection moulding: A guide for designers and end-users (Free feature) ______________________________________ |
