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Specialty Manufacturer of Heat Sink Products
Unique Application of Thermal Analysis Tool


MIZUTANI ELECTRIC IND. (hereinafter Mizutani Electric), a specialty manufacturer of heat sinks and radiators for electronic devices, has been using Cradle scSTREAM for thermal analysis. Computational simulation has enabled the company to decrease the amount of experimental testing needed and substantially reduce their product development lead-time. Now they want to take another step to advance their simulation capabilities by drawing on their past experiences. To learn more about how Mizutani Electric is advancing the use of simulation, we interviewed Yousuke Watanabe, assistant manager of the Mizutani Electric Technology Center.

Yousuke Watanabe
Assistant manager of technology center

Reducing Lead-time using Intensive Simulation Analyses and Building Expertise

 One of Mizutani Electric's primary reasons for using simulation was to reduce product development lead-time. Before introduction of the software, engineers repeatedly conducted production tests to verify design changes. This often took several weeks to complete. CFD analysis has reduced the number of trial production tests needed to validate a design.

 In addition, Mr. Watanabe points out that appropriately dealing with unknown and/or variability in physical properties is crucial for obtaining high accuracy results and speeding up the process. Mizutani Electric's extensive product and manufacturing experience has been important here. They can propose an optimum product design for their customers by resolving unknowns associated with physical properties using their vast product and manufacturing experience. Mr. Watanabe explains that "The effects of the physical properties are directly reflected in the simulation analysis results, but the thermal analysis for the experimental test results is less accurate. We can use the simulation analysis to conduct sensitivity analyses to understand which physical properties are most important. By doing this we can make the overall analysis process more accurate. This also enables us to make the most of our know-how as a heat sink manufacturer."

 Mr. Watanabe goes on to say that they always try to design their analysis conditions so they can easily identify the causes for differences between the simulation and experimental results. There are always some differences between the simulation and experimental results. However, Mr. Watanabe says "We always work on improving our ability to trace the cause of the differences using the expertise we've accumulated over many years."

Fig. 2 HEATLANE® Heat sink (click to enlarge)

Analyses Enhance the Development of a New Product

 Mizutani Electric's patented HEATLANE® Heat sink uses a HEATLANE® plate with a significantly higher thermal conductivity compared to conventional materials and designs. The plate is bent in layers and fins are connected to each layer. The very high thermal conductivity of the plate enables the HEATLANE® plate to conduct heat to the end of the plate much quicker than aluminum or copper boards. When the fin is long, neither aluminum or copper can effectively conduct heat to the end of the fin. The HEATLANE® plate equalizes the heat in the heat sink and maximizes the efficiency in a small space.

The example in Fig. 2 uses a plate bent in an S shape which transports heat to the upper stage fin for the best dissipation performance. Mr. Watanabe explains, "We believe that we can potentially replace a conventional water cooling system with the HEATLANE® method."

Fig. 3 The result comparison between
​the current and previous heat sinks
(click to enlarge)

 Optimal fin heat dissipation will occur when the metal temperature is uniform across the fin. The analysis for a conventional fin revealed that the temperature varies greatly from one end to the other. scSTREAM was used to identify concepts that could improve fin temperature uniformity. This analysis showed that heat dissipation efficiency could be improved 40% over a conventional fin by using special soldering techniques (Fig 3). Mizutani confirmed that the soldered fins performed in actual experimental tests just as scSTREAM predicted. This helped build their confidence in analytical simulation.

Fig.4 EC-JOINT (called ECO-JOINT)

 ​​Another concept nearing production release, "EC-JOINT (Registered utility model)", has been shown to improve heat dissipation e ciency by 20%. For this design, a heat pipe is connected to the side of the heat sink where the fins are located. No secondary material such as solder or adhesive is used because the heat pipe is tightly pressed into the heat sink to make direct contact. The heat pipe concept is both economical and environmentally friendly (doesn't require use of secondary materials). One critical design/manufacturing requirement is producing an extremely at heat pipe so that it can make perfect contact with the heat sink. A special capability of "EC-JOINT" is that heat can be uniformly conducted across the entire fin even if the heat source generates heat in a local area or disperses it across the fin with a varying distribution. In addition, because the heat pipe is set to the side of the heat sink where the fins are located, design engineers can easily allocate parts to oneside of the base face. This places the parts on one side of the base face reducing its overall size. This is an extremely important benefit for Mizutani Electric customers.

Seeking Ways to Get Even More Benefits from using Simulation

 Mr. Watanabe also discussed future improvements for thermal analysis. Certainly simulation at Mizutani Electric has reduced the number of production tests needed to validate a design. This has shorted product development lead-time. But Mizutani Electric would like to take the next step by seamlessly integrating the company's accumulated know-how with the software tool to design new composite radiators that will be developed over the next few years. Mizutani Electric believes an opportunity exists to shorten development time even more for the new composite radiators by harnessing the lessons learned from previous analyses.

What is Expected from CRADLE?

 Mr. Watanabe says, "In scSTREAM Version 10 we can input an upper limit for heat transport that enables us to stop the computations and eliminate unnecessary analysis. This brought a great advantage to our product development." Mitzutani Electric also expects Cradle to improve the compatibility of the data between older versions of scSTREAM and the current version. At this time, data compatibility is primarily between the current version and the previous version. Mr. Watanabe says he is satisfied with the current functions in scSTREAM, but still has expectations to improve the usability of the software even more. He says, "It would be even more convenient if we could exchange model data between scSTREAM and HeatDesigner."

*All product and service names mentioned are registered trademarks or trademarks of their respective companies.
*Contents and specifications of products are as of April 31, 2013 and subject to change without notice. We shall not be held liable for any errors in figures and pictures, or any typographical errors.

Company Details


Established 1967
Business Production and sales of radiators for semiconductors
President & CEO Kazuo Mizutani
Head Office Chiyoda-Ku Tokyo
Employees 80 employees as of March 31, 2009
Capital 90,000,000 JPY



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