Cooling of injection molding machine
Shanghai Meluck Refrigeration Equipment Co.,Ltd. is an advanced enterprise specialize in R&D, manufacturing, marketing, construction contracting, post sale service of refrigeration and relevant equipments. As one of the leading refrigeration product suppliers, Meluck has its products include over 20 series as box type, open type condensing units, air cooled and water cooled compressor racks, industrial chillers, air coolers of MAC, FD, D, EV, and DHF double side blowing, water defrosting air coolers, fin and copper type condensers, Shell and tube type condensers and evaporators. etc.
Everyone know the widely application of the chiller,one of the applocation is cool the mould,basically ,most of the moule manfacture have chiller equiment,So today I will come to indroduce you how to select suitable chiller in the production of mold.In the other side,because the injection molding machine often used with cold water machine, so this will be introduced.
一、how to choose the chiller.
In the factor ,a set of mould just the set of heat exchanger ,heat from the molten plastic into the mold,then the mold into the cooling medium circulation - - ice water,Only a very small pressure template part into the air and injection molding machine.As everyone knows,the cycle of plastic molding, the considerable part of time on cooling, sometimes be accounted for more than 80% of plastic molding cycle, so control the cooling time to a minimum is absolutely necessary.For example,one set of plastic molding cycle is 20s,If the change the cooling tower water but use chiller produces ice water for cooling, it can be shortened to 16 seconds .Although choose with cold water machine cost is higher,it can make the output increase 20%.In the long-term production,it can make great profit. In that way,how to choose the ice energy? From the above we can know, it connevt with the specific heat molding material, melt temperature , weight and Product demoulding temperature.
General injection molding mold cooling, cold water pressure is 0.1~0.2Mpa can meet the requirements, and the microcomputer global function of cold water can meet the this request, when the pressure is higher than 0.2Mpa,nedd make the new planning,use corresponding pressure pump to meet the needs of water supply system.
Relationship between flow and diameter:：
Pipe diameter ：3/8″， 1/2″， 3/4″， 1" ，1'/4″ ， 1'/2″ ， 2″ ， 3″
Flow rate：12 ， 20 ， 35 ， 60 ， 90 ， 130 ， 230 ， 560
the calculation formula of cold water energy for mold:q=w×c×t×s
q is for the energy of the ice water:
is weight of the material；
C is the specific heat of raw materials for plastics kcal／kg℃；
t is The temperature contrast of melt and when release the products；
s is for the safety,(1.35-2.0),when the single matchs, usually choose the small value,when
one set of chiller connect with several mold use the maxiam value。For example,one set od mole producre PP product per production is 50kgs,then require how much of the cool energy? what kind of chiller is reasonable. q=50×0.48×200×1.35＝6480 （kcal／h）；need 6480kcal／h .choose chiller Is203s is suitable。
In the practical use of cold water machine , it is difficult to obtain the complete data.According to our previous years of planning, supporting sales experience,? T = 200 ℃, it is a average value after many common products statistics.
If the mold with hot runner, should add the energy of hot runner to calculated the energy cooling capacity, general hot runner is kW as the unit, when calculated the unit into kcal/ h, 1kw=860kcal / h. If the supply of factory water adequatly, low temperature,low cost, it's Needn't to use cold water machine, but it is generally unrealistic,unless the factory located in lower water temperature near the lake; another is the use of deep well for the city to meet the need of water temperature and flow, but the cost is too high.This method can be used for experimental device, but for the factory, this is unrealistic。
二、Ice water temperature differeance
Mold cooling fluid (water)temperature is generally dependent on the processing materials
and products shape changes,such as polystyrene thin beaker,mold requires ice water temperature below 0 ℃; and the majority of cases, the mold required ice water temperature was higher than 5 ℃, microcomputer Full function of cold water can provide more than 5 ℃ cold water, low temperture intelligent temperture control chiller can meet the temperature below 5 ℃ and 0 ℃。
Setting the input and output temperature of ice is often according to product requirements,in many cases, the temperature of 3-5 ℃is the mostideal,But sometimes there is a need for temperature at 1-2 ℃. The temperature difference is small, means that the same heat out, water flow needs of the greater, contrariwise the required to the flow rate is small.For example: temperature difference is 5 ℃, need flow rate 60L,when the temperature diference is 2 ℃ ,the flow rate will need 150l.
三、Ice water flow rate
The temperature of ice flow mold required for direct and mould to take away the heat and ice import mold. For example: must be 6480kcal / H heat from the die away, if the temperature is 3 ℃, then at least need to flow for how much? Water flow rate q=6480 / 3 / 60=36 (L / Min).
四、Ice water quality theory
Water softening, in the process of using chiller, is a problem that can not be ignored, the water PH value needs to be constantly observed, the best ph Value should be equal to 7, more than 7 PH values produce corrosion phenomena terribly, if not take measures , theevaporator, inside mould will fur up, will play the insulation role, seriously, make theenergy conversion decreased by 30%. Obviously this requires softening of hard water consideration.The most effective way, is configured an electronic hard water softener in the system, such softener is designed acording to ion exchange principle . According to the flow configure different of Softening specificatly, is directly connected to the circulating water pipes, the general configuration and softening device costs are not too
high , also can add a certain proportion detergent in the circulatory system .
五、Ice machine flow rate and pressure
Generally injection molding mold cooling, pressure of cold water is 0.1 ~ 0.2MPa can meet the requirements, and the microcompture whole funcation chiller can meet the this requirement, when the pressure is asked higher than 0.2MPa, need new planning, in order to use the corresponding pressure from the pump to meet the needs of water supply system.
六、Cooling of the hydraulic oil cylinder and material barrel feeing section
Usually the hydraulic oil and barrel feeding section adopt the cooling tower water cooling, because this is not the best method, wfq0803wf just see the production cost , is also very economical,unless there are special requirements for its temperature, can be used in ice water to cool its.Usually the hydraulic oil and barrel feeding section adopt the cooling tower water cooling, because this is not the best method, wfq0803wf just see the production cost , is also very economical, unless there are special requirements for its temperature, can be used in ice water to cool its.七、 Keep warm of the ice water pipe
Ice water pipeline must be heat insulated, because pipeline insulation can not only prevent cold capacity seriously loss , but also prevents the dew formation in the outer wall of the tube . For example: the water temperature is 10 ℃, the environment temperature is 30 ℃, a 25 meters long, the heat radiation surface area for metal pipeline 25m2 can reach 750kcal / h, this is 10% refrigeration quantity of 3hp compressor , 6% of 5HP compressor.
Connect the cold water machine, usually adopts reinforced rubber hose connection, because the hose itself have thermal insulation function, but the length of more than 5m , also want to consider the appropriate insulation. In the use of chiller, another device which closely linked with is the injection molding machine, as well as the association is so big, that how to choose the injection molding machine, let us introduce to you. Domestic vertical, horizontal injection molding machine under normal temperature conditions, cooling water condensing temperature water-cooled chiller in below 35 degrees (air cooled type Chiller condensing temperature is below 43 degrees) of the matching.
A、First method: 1HP cooling water chiller with 80t Injection molding machine with temperture 5-10
1HP cooling water chiller with 100t Injection molding machine with temperture 10-15degrees
1HP cooling water chiller with 120t Injection molding machine with temperture 15-20 degrees
(air-cooled chiller for cooling is cooling water chiller 0.8 times, 1HP air cooled machine can be equipped with 64 tons of clamping force of injection molding ,machine temperature control in 5-10 degrees)
B、The second method:1hp water cooling chiller can match the injection molding machine with the injection mold quality is 100z once time and the temperature is controled in 5-10 degrees
C、Matching of chiller and cooling tower, according to the practical experience , 1HP chiller need about one set of 1.2 RT cooling tower can take away the heat generated by the chiller.
Contact Meluck for more detail, hotline:86-19979207433，Phone:86-21-39199141
