China Injection Mold Cooling System
Designed for cooling
Cooling designed to make the uniform cooling and is within a short time fix molding, waterways arranged a direct impact on the quality and cost of the molding cycle of the product
For Quality: When water is used to control the molding mold temperature, mold temperature and its fluctuations on product shrinkage deformation, dimensional stability, mechanical strength, stress cracking and surface quality are all affected. Main features: surface finish, residual stress, crystallinity, thermal bowing
In order to control the injection mold temperature, 100 degrees below, usually adopts water as cooling
medium.Cooling water temperature by circulating water pump of the thermostat, circulating in the
cooling channel is arranged on the mold manufacturing internal, to stabilize the mold by heat conduction
and radiation temperature.
Cycle usually from the injection mold external cannot observe the cooling water (if the mould is transparent
enough to observe the into into into). In fact, the cooling water flow mode from fluid mechanics is the existence
of "laminar" and "turbulent" two modes.
In order to efficiently plastic mold temperature control, cooling water state is best "turbulent" state.
"Turbulence" state can be tailored by the fluid dynamic viscosity coefficient, hole diameter, velocity of such
decisions "Reynolds number" of this indicator for approximately predict.
Only water speaking words, in order to make the cooling water into turbulence, by using the above a certain
flow speed so that to achieve the water flow in the manner.
That is to say, if you have identified a cooling hole die diameter, in order to achieve turbulent, only the circulation pump supply rate was maintained at a certain value above can supply.
In this case, because of the dynamic viscosity coefficient will change due to water temperature, so it needs to flow through the change of water temperature.
Injection mold cooling system design principles
(1) reasonably determine the center distance and the cooling duct from the cooling water hole spacing and
cavity wall of the cooling duct, namely how much water cooling hole number, a great impact on the mold
cooling effect.FIG (a) shown in the temperature of the cooling duct to ensure uniform distribution of the cavity
surface, and Fig (b) the structure shown by the distance between the opening of the cooling duct is too large,
so that the cavity surface temperature changes greatly, from 53.33 ℃ to 61.65 ℃ range, causing parts of the
article uneven shrinkage.
(2) as much as possible from the cavity surface to cooling hole is equal when the plastic wall thickness uniformity, the cooling medium from the hole and the cavity surface should be the same everywhere, that arrangement and shape of the cavity water hole as far as possible consistent, as (a). When uneven thickness plastic parts, wall thickness should be strengthened cooling water holes should be close to the cavity distance is smaller, but not less than 10 mm.
(3) reduce the temperature of the cooling medium such as human population at the poor water and outlet water temperature too much will make the injection mold uneven temperature distribution, especially for very long process large plastic parts, material flow, the lower the temperature. For the whole of the cooling rate is substantially the same, in addition to shortening the cooling circuit, but also by changing the arrangement in the form of cooling channels. Fig (a) shown in the form of people and water and water temperature, and plastic parts uneven cooling; and Figure (b) in the form of overcoming the above drawbacks, cooling effect is good, but the cooling water consumption.
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