/ep_edm/en/contect_458.html SHINI PLASTICS TECHNOLOGIES, INC.

Special Reports

2011 Quarter 2 Issue 7

Application of Air-cooling Chamber on Plastic Molding

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Working principle

 

 

 

 

 Working Principle

 

In order to replace mould sweat dehumidifiers which have high energy consumption, Shini developed Air-cooling chamber (SACC) as below:

 

SACC needs to collocate with water chillers or chilled water system and uses heat exchanger with cooling water to finish heat exchange and dehumidification to high temperature air. Centrifugal blower fan firstly absorb inlet air, again through the fan outlet cooled air is discharged after the treatment. Cold water after heat exchange is sent back water chillers or chilled water system for cycle use through cooling water outlet.

 

Before SACC start working, cooling water inlet should connect with and water chillers or chilled water outlet of chilled water system. And cooling water outlet should connect with water chillers or circulating water inlet of chilled water system, by adjusting the flow of intake cooling water and cold water temperature can get different air outlet temperatures; Switch on SACC, cooling water began to circulate in heat exchanger, and after operation, centrifugal blower form the closed channel by integrating air collecting cover, heat exchanger and air inlet joint. Then closed channel would absorb external high-temp. air into heat exchange to get through heat exchange and dehumidification. Intake air after treatment enters centrifugal blower through air collecting cover, then blower send cold air to cold air outlet. The temp. of exporting cold air can be detected temp. controller. Return air cover is optional for recycling the exporting cold air.

 

Features and application of SACC

SACC adopt side air suction with a simple structure. It occupies small space for easy movement. Can be collocated with water chillers or cooling system. Equipped with anti-phase, default phase, overload and high temperature protection. Both alarm and warning light would send alert of breakdown, making operation secure and reliable. Equipped with the pull-out air filter which has simple structure and it is convenient clean filter screen. The air throughput is 3000m3/hr and circulating return air device is optional. Air outlet can be adjusted between 12~24℃ and air-out dew-point is lower than 10℃; This series are applicable for extrusion film line cooling, cold-air stereotyping and preventing moisture condensation of moulds. Return air device is optional if used in the area with high moisture.

 

Why choose SACC

In plastic molding, too much air moisture would affect finished products qualities, leading to water-drop on the surface of goods. Therefore, mould ambient temperature needs to be controlled to maintain a sustainable good quality. Air-out dew-point of SACC is lower than 10℃ and temperature can be adjusted between 12~24℃, which can effectively control air temperature and moisture around moulds so that dry air would be full inside mould indoor to avoid dew drop during mould cooling.

 

The current blow molding machine adopts two-step way in which plastic material is made into preforms and then blow molding is finished afterwards. The plastic material in normal use at present is PET pro-environmental plastics.

 


Processes of blow molding can be divided into two steps:


1. Preforms are exposed to high temp. tube to soften body part. To keep the shape of bottleneck, it is unnecessary to heat up performs mouth. Thus some cooling facilities are needed to cool down the mouth part.


2. Place the preheated preforms into moulds and air-inflated with high pressure to finish blow molding. For the sake of controlling cooling time and ensuring goods quality, keeping a constant ambient temperature and moisture is very important.
 

 

For the air-cooling of large-sized PE plastic bags, a better controlling of air temperature and moisture during the cooling for large-sized PE plastic bags molding is fundamental for raise production volume and quality.

 

Temperature control of blow molding moulds: too low temperature would make parison temperature drop quickly so the transformation of parison blow molding get affected, which leads to a bad fitting with moulds. The figure and outline of blow molding products are far from distinct; too high temperature would prolong cooling time of parison inside moulds thus efficiency to be lowered; if cooling time were not prolonged, product’s defects like deformation, shrinkage and lack of gloss would come into being due to inadequate cooling. Cooling water and air-cooling are two different ways in controlling moulds temperature and sometimes these two ways may be adopted together to achieve a more favorable effect. In a word, one of crucial factors in ensure quality is combing temperature control of blow molding with shortening cooling time of parison.

 

 

SACC-3000