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    Natural Convection and Inclined Parallel Plates 

    by
    thermal
    Published on 19th May '12 12:03     Number of Views: 2024 
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    Natural convection has been used to cool electronics for ages. It is a simple and reliable method. The big drawback, of coarse, is that the cooling capacity is limited. All possible means to enhance natural convection are therefore more than welcome. This article is about one particular method, inclined parallel plates.

    My first encounter with this issue happened when I was trying to design a cooling system for active electronics mounted in radio masts. Fans were excluded for reliability reasons. The only realistic alternative was therefore natural convection. The equipment was enclosed in metal boxes that needed to be cooled from one side. Applying a wide but not very high heat sink could have solved the problem but horizontal structures are not considered esthetical in radio masts. A second restraint was therefore that the heat sink not could be made much wider than the mast itself.
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    The thermal interface problem 

    by
    thermal
    Published on 18th May '12 20:08     Number of Views: 1423 
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    A few years ago solving an interface problem was just a matter of applying thermal grease. Things are much more complicated today. Not at least because the heat fluxes are increasing. The large flora of commercially available interface materials is a good illustration of that. The interface problem has many facets and they can not all be brought up in this article. Fortunately, there are experts to consult. The purpose of this article is therefore not to be complete, nor profound. It is rather to present an overview that hopefully could help some readers to become better discussion partners when consulting the real experts.
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    Front-end Thermal Design 

    by
    thermal
    Published on 15th May '12 22:00     Number of Views: 1412 
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    The thermal design has from its early days and forward focused on the calculation accuracy problem. Great progresses have been made. The best methods nowadays have a quality beyond what is needed for most standard applications. The back side of the coin is that these methods require plenty of detailed inputs, which makes them poorly adjusted to the requirements in the early phases of a design process.

    This article will discuss several aspects of front and back end thermal design. It will also expose some front end methods that have been practised by the author for more than 10 years and still are competitive.
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    iPhone & Android apps now available FREE! 

    by
    admin
    Published on 7th May '12 16:20     Number of Views: 1968 
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    Great news! We are delighted to announce that our FREE apps are now available for iPhone and Android mobile devices.

    This is the ultimate app for mechanical engineers! The MDF app gives you access to www.mechanicaldesignforum.com from your mobile device. Our popular discussion forums put a global network of mechanical engineers at your fingertips, allowing you to share knowledge, exchange ideas and make industry contacts. The MDF app also provides you with access to technical articles, including manufacturing process design guides and CAD tutorials.
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    Getting Started with 3D Printing 

    by
    cwarner7_11
    Published on 6th May '12 00:33     Number of Views: 7834 
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    Here is a description of my recent experiences building a 3D printer and getting it up and running, for those that might be interested in this technology.

    Includes my first print results which turned out to have surprisingly good accuracy (although needing some tweaking to get things "printable"). Good accuracy? I can not measure the variation from 90º on my printed parts, all axes combinations. Dimensional tolerances are on the order of 0.7 mm., all three axes. At least half of this can be attributed to material shrinkage during cooling. Improving surface quality will most likely improve tolerances significantly. Coming soon - tweaking my 3D printer for improved print quality.
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    Area of plane shapes 

    by
    admin
    Published on 28th Apr '12 23:30     Number of Views: 1582 
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    Here's a useful guide to calculating the area of basic shapes.



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    Electro-discharge machining (EDM) 

    by
    GarethW
    Published on 28th Apr '12 08:40  Number of Views: 7167 
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    Process Description
    Electro-Discharge Machining (EDM) is machining with sparks. The work-piece is held in a jig submerged in a dielectric fluid such as kerosene. A power supply generates rapid electric pulses that create a discharge between the work piece and an electrode (a continuous wire or a shaped graphite form) at the point at which the two are closest. The discharge creates a plasma causing the melting, and probably the vaporisation, of a minute bite of material, slowly eating into the work piece; the debris is swept away by the dielectric fluid. EDM is remarkable for its ability to shape difficult materials (provided they are conductors) and do so with great precision.
    Any electrical conductive material can be machined irrespective of hardness.
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    Convert those units the easy way! 

    by
    GarethW
    Published on 28th Jan '12 23:32     Number of Views: 5270 
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    Here's is a great piece of freeware. It's simply called "convert" by Josh Madison. It's an amazingly useful program - something that every mechanical engineer should have on their desktop! It's function is simple - it converts any imaginable unit of measure. Force, mass, volume, acceleration, density, distance etc. Here's a screenshot:


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