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some rules of Thumb
Definition: Mold: 1) A hallow form or matrix into which a plastic material is placed and which imparts to the material its final shape as a finished article. 2) To impart shape to a plastic mass by means of confining cavity or matrix. Heat Exchanger: A device for exchanging heat from one medium to another
Rules of thumb:
As mention previously the following diagram should explain the offset of fluid lines to wall cavity.
The above sketch shows that the water channel has a diameter of d and that by using that as a basis of measurement their placement in the mold can be calculated. The figures of 3d and 1.5 d are assuming maximum for placement purposes. The rings around the water channels represent distance, and are meant to show what is happening.
Another bit of data is that the diameter d can be based on part thickness as follows:
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Part Thickness mm
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Channel Diameter mm
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'T'
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'd'
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2
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8-10
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4
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10-12
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5
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12-15
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A note of caution and or the math, more water flow into the mold is better.
In most cases the author has come across yes, but this is not necessary true on a cost basis for the plant, in regards to energy and equipment cost. An interesting article on testing of water flow has recently shown that once the water has reach a turbulent flow rate any additional flow is not improving the cooling rate enough to justify the cost of this (the processor may need to determine for their own application). This is very enlightening as typically everyone has always wanted more flow more flow, yet in fact once a flow rate of turbulence has been reached it is good enough, to stabilize steel temperature, and thus heat exchange rate.
Thus one can say we need turbulence. See article:
http://www.ptonline.com/articles/measuring-the-magic-of-turbulent-flow-mold-cooling
*** The influences of cross-sectional area 5th power of the diameter. An example of this is that for a diameter of 8 mm the pressure drop per meter is 3 times greater than for a 10mm diameter.
The use of loops and or a serial flow path within the mold if monitored is okay, and may need to be split due to issues, while the use of a parallel system can individualize each circuit they must then be monitored for flow and pressure, temperature so that it is uniform.
***** While the above is the data, the part criticalness shall determine most of this. Each circuit should be tested for flow and pressure drop. Correct, how is one to know what flow one has prior to an issue if they are not measured. Again a simple way is to measure temperature difference from in to out on that circuit, (when in operation and mold is operating).
SlSilvey
11022014.01
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