First, how the optional chiller
In fact, a mold is a heat exchanger, heat from the molten plastic incoming mold, then the mold incoming continuously by circulating a cooling medium - ice water, only a small part into the air and the platen of the injection molding machine. Is well known, plastic molding cycle, a relatively large portion for cooling, and sometimes can be accounted for more than 80% of the plastic molding cycle, the cooling time is controlled to the minimum absolutely necessary. Example, a molding cycle is generally 20 seconds, such as cooling water use the Chiller generated ice water instead of the original cooling towers, it can be shortened to 16 seconds. Although originally selected with the chiller cost is higher, but it will enable the production increased by 20%, and can achieve great gains in the long-term production. So, how to choose ice water energy? From the above we can know that it is the specific heat of the molding material, the melt temperature, weight and temperature products during demolding. Of a mold the ice-water and the energy of the desired formula: Q = W × C × △ T × S
Wherein: Q is the energy of ice water required kcal / h;
W is the weight of the plastic raw materials kg / h;
C is the plastic raw materials than hot kcal / kg ° C;
The temperature difference △ T is the temperature of the melt and products Stripping ℃ (see table);
S is a safety factor (usually take 1.35-2.0), when the stand-alone match, generally choose a small value, whichever is greater when a chiller with multiple die match, If you choose air-cooled chiller, S should appropriate choice.
For example: a mold to produce PP products, the hourly production of about 50kg, asked the cooling requirements for how much? Much chiller should be equipped with appropriate?
Q = 50 × 0.48 × 200 × 1.35 = 6480 (kcal / h);
Hour need 6480kcal / h cooling, the choice the PR the Chiller process in difficult to obtain a more complete data. According to our previous years of planning, supporting sales experience, △ T = 200 ℃, it is an average of many commonly used products after years of statistics.
If the mold with hot glue Road should be added to the energy of the hot glue Road cold calculation the the generally hot glue Road KW units, unit conversions should be calculated as kcal / h 1KW = 860kcal / h. Adequate water supply plant, low temperature, low cost, and you do not need to use chiller, which generally is not realistic unless the factory lower lake water temperature; Another is the use of The city deep well water supply to meet the needs of the temperature and flow, but are often too costly. The experimental apparatus can use this method, but for the plant, it is impractical to do so.
Second, the ice water temperature difference
Mold the temperature of the cooling fluid (ice) is generally subject to the processing materials and the shape of the article to large changes, such as polyethylene thin-walled beaker, the molds require ice water temperature below 0 ℃; while most other cases, the mold the temperature of the ice water requirements are more than 5 ℃, microcomputer full-function chiller to provide more than 5 ℃ ice water, low temperature smart thermostat chiller can meet the requirements below and up to 0 ℃ 5 ℃.
The mold at the entrances to the difference in temperature of the ice water is often based products require to set, in many cases, the temperature difference is 3-5 ° C is ideal, but sometimes also requires that the temperature 1-2 ° C. The smaller the temperature difference, the means to take out the same amount of heat, the greater the flow of ice water, whereas the smaller the required flow. Such as: temperature difference of 5 ° C, the flow needs 60L, to the temperature difference between the 2 ℃, the traffic you need to 150L.
Third, the ice water flow
The flow of ice water for a mold is directly related to the temperature difference between heat and ice water out of the mold and the mold away. For example; want 6480kcal / h of the heat away from the mold, if a temperature difference of 3 ° C, then at least the required flow? Ice water flow rate Q = 6480 ÷ 3 ÷ 60 = 36 (L / min).

, Ice water processing
Softening of the water chiller is a problem that can not be overlooked, the PH value of water need to constantly observing, The Best PH value should be equal to 7, the PH value greater than 7 will have a terrible corrosion phenomena, such as do not take measures, will be reduced by 30% in the evaporator, mold fouling, will play the role of thermal insulation, serious, its energy conversion effect. Obviously This requires consideration of the softening of hard water. The most effective way, and can be configured in the system, an electronic water softener, such softening is based on the principle of ion exchange design production. According to different softeners can be configured in different specifications, and is directly connected to a circulating water pipeline, the general configuration of the flow will not be too high cost of water treatment softeners, detergents adding a certain percentage to the circulatory system on a regular basis .
Chiller flow, pressure
General injection molding mold cooling, ice water pressure selection 0.1 ~ 0.2Mpa to meet the requirements to meet this requirement, and microcomputer full-function chiller when the pressure requirements higher than 0.2Mpa additional planning, in order to facilitate the corresponding pressure to meet the needs of the system water pumps.
The relationship between flow and diameter table:
Diameter 3/8 "and 1/2" 3/4 "1" 1 '/ 4 "1' / 2" 2 "3"
Flow 12 20 35 60 90 130 230 560
, Hydraulic oil and cooling of the barrel feed section
Usually hydraulic oil barrel feeding zone using water cooling towers to cool because it is not only the best method, production costs alone watching is also extremely economical unless specific requirements, available ice water temperature its cooling.
Seven or ice water pipe insulation
Ice water pipeline insulation, pipe insulation can not only prevent the the cold serious loss, but also prevent dew condensation formed in the outer wall of tube. For example: the ice water temperature of 10 ° C and an ambient temperature of 30 ° C, a 25-meter-long, the surface area of ​​25m ² thermal radiation of the metal pipes up to 750kcal / h, which is almost a 3HP compressor cooling capacity 10% 5HP compression cooling capacity generated by the machine for about 6%.
Chiller and mold connection, usually with enhanced hose connection, because the hose itself insulate function, but longer than 5m, should be considered a moderate insulation.
The Schedule: different molding materials require injection and mold temperature and hematocrit heat.
Material injection temperature ° C mold temperature ℃ hematocrit hot Kcal / kg ℃
Polyethylene 160 ~ 310 0 ~ 70 0.55
Polystyrene 185 ~ 2500 ~ 60 0.35
Nylon NYLON 230 ~ 300 25 ~ 70 0.58
The polycarbonate the PC 280 to 320 From ~~ 130 0.03
Polypropylene PP 200 ~ 280 0 ~ 80 0.48
ABS 180 ~ 260 40 ~ 80 0.40