Characteristics and Application of SMD

We usually use cooled water to cool down mould and products to obtain shorter cycle time in injection molding process. But when the temperature of the moulds surface is lower than the dew-point of ambient air, the vapor in the ambient air will be condensed on the moulds surface. And this phenomenon has a bad effect on the product quality and production efficiency. Whats worse, it can also corrode the mould and cause environmental pollution. Therefore, our company developed the SMD series of mould sweat dehumidifier to deal with it. This series apply honeycomb rotor system to dehumidify the ambient air of the mould, ensuring ambient air with low dew-point (0 ~ -10℃), and the dew-point will be constant in different seasons and can reduce the rate of defective products.

The appearance of mould sweat dehumidifier is showed in figure 1. The working principle as follows: the vapor of ambient air is absorbed by the hygroscopic material of honeycomb when going through the rotor, and then desorbed in the regenerative section by the regenerative heated air. As the rotor is rotating slowly, two air streams pass through honeycomb and the vapor of the air shifts from being absorbed by the hygroscopic material in the dehumidifying section to be desorbed by the heated air in the regenerative section, resulting constant low dew-point ambient air for using.

P.I.D. temperature control is applied in our mould sweat dehumidifiers, and you can set regenerative temperature and actual dew-point for precise temperature control. As showing in figure 2 and figure 3, there are two typical applications in injection molding system: One is open design (figure 2), and the other is closed design (figure 3). In wet hot area, lots of vapor is included in the ambient air. Our closed system will be applied for preventing the honeycomb rotor from absorbing lots of vapor from the air. The temperature of process air between air outlet and the mould is approximately 30℃, and the vapor in the ambient air will not condense on the surface of the sight-glass of the injection machine, especially suitable to the high-moisture areas. But usually, open system will be applied, which adopting standard dehumidifiers.

Recently,the structure of old type was improved as follows: Firstly, cancelled the air collection hood to reduce the cover area and down the cost without affecting its performance. Secondly, replaced the double honeycomb and vertical install structure with single honeycomb structure, and optimized the installation area for the internal components. With these improvements, malfunction rate is reduced, as well as reasonable structure, convenient maintenance, low energy consumption, and low cost.