How to achieve high cycle molding
Selection of appropriate cooling equipment
High-cycle molds
Shortening lightweight time (ideal plasticization and injection volume)
It is necessary to consider the above three points.
Selection of appropriate cooling facilities
Stable mold temperature is essential to reduce dimensional variation.
Generally, equipment selection is made from the following process.
(1) Calculation of total heat content
①Calculation of calorific value of resin
1. Shot weight ・・・・・・A1(kg/shot)
2. Number of shots per hour・・・・・A2(shots/h)
3. Specific heat of molten material・・・・・A3(kcal/kg・℃)(0.25-0.4)
4. Injection temperature of material (temperature at front) - A4(°C)
5. Product removal temperature・・・・A5(℃)(80～120)
6. Latent heat of solidification of molten material・・・・A6(kcal/kg)(40～50)
(A1×A2)×(A3×(A4-A5)+A6)=Heat value of resin
② Calculation of heat capacity of hot runner
Hot runner capacity・・・・B1(kW)
Percentage of the heat load・・・・B2(%)(=80%)
(B2÷100)×B1×860=Hot runner heat quantity
③ Calculation of total heat quantity
Heat value of resin + heat value of hot runner = overall heat value
(2) Temperature controller flow calculation
Flow calculation for temperature controllers
Conditions
1. Mold inlet/outlet temperature difference・・・C1(Normally 1 to 1.5℃)
2. Specific heat of medium・・・・C2(1 kcal/kg°C for water)
3. Conversion of heat per minute to per hour
Total heat value ÷ (C3 × C1 × C2) = temperature controller flow rate
Generally calculated with a mold inlet/outlet temperature difference of 1 to 1.5°C
↓↓
Calculated at 0.5°C to minimize dimensional variation in molded products
Using the above formulas and the values set by the assumptions, we can determine the specifications of the cooling system required for a high cycle
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