After plastic injection molding, what are the factors that affect the cooling rate of the product?

After plastic injection molding, it is mainly the wall thickness of the plastic product. The greater the thickness of the product, the longer the cooling time. Generally speaking, the cooling time is approximately proportional to the square of the thickness of the plastic product, or proportional to the 1.6th power of the largest runner diameter. That is, the thickness of the plastic product is doubled, and the cooling time is increased by 4 times.

1. Mold material and its cooling method. Mold materials, including mold core, cavity materials, and mold base materials have a great influence on the cooling rate. The higher the thermal conductivity of the mold material, the better the effect of transferring heat from the plastic per unit time, and the shorter the cooling time.

2. Cooling water pipe configuration method. The closer the cooling water pipe is to the mold cavity, the larger the pipe diameter and the larger the number, the better the cooling effect and the shorter the cooling time.

3. Coolant flow rate. The larger the cooling water flow (generally to achieve turbulent flow), the better the effect of cooling water to take away heat by thermal convection.

4. The nature of the coolant. The viscosity and thermal conductivity of the coolant will also affect the thermal conductivity of the mold. The lower the viscosity of the coolant, the higher the thermal conductivity and the lower the temperature, the better the cooling effect.

5. Plastic selection. Plastic refers to the measurement of the speed at which plastic conducts heat from a hot place to a cold place. The higher the thermal conductivity of the plastic, the better the heat conduction effect, or the lower the specific heat of the plastic, the temperature is prone to change, so the heat is easily dissipated, the heat conduction effect is better, and the required cooling time is shorter.

6. Processing parameter setting. The higher the material temperature, the higher the mold temperature, the lower the ejection temperature, and the longer the required cooling time.