What are the reference bases for cooling time in injection molding processing?

In the injection molding process, cooling time is one of the key factors affecting product quality and productivity. Reasonable determination of the cooling time can not only ensure the quality of products, but also improve productivity and reduce energy consumption.

So, how to determine the cooling time? The following are some key references.

1. Material properties: different plastic materials have different thermal conductivity, thermal diffusivity and melting point. The higher the thermal conductivity of the material, the faster the cooling rate; the greater the thermal diffusivity, the more uniformly the internal heat is distributed; the higher the melting point, the longer the cooling time. Therefore, when determining the cooling time, the first thing to consider the physical properties of the material used.

2. Product thickness: the thickness of the product directly affects the length of the cooling time. Generally speaking, the thicker the product, the longer the cooling time. This is because it takes longer for the heat inside a thick-walled product to completely escape to the surface, thus extending the cooling time.

3. Mold temperature: The effect of mold temperature on cooling time is also very significant. The lower the mold temperature, the faster the cooling rate and the shorter the cooling time. However, too low a mold temperature may lead to rapid solidification of the plastic material, the formation of internal stresses, or even cracks. Therefore, the control of mold temperature needs to take into account the material properties and product quality requirements.

4. Injection cycle: The injection cycle includes injection time, pressure holding time and cooling time. When determining the cooling time, the balance of the entire injection cycle needs to be considered. If the cooling time is too short, it may cause the product to enter the next cycle before fully cured, affecting product quality; on the contrary, too long cooling time will reduce production efficiency.

5. Environmental factors: the ambient temperature and humidity of the production plant will also affect the cooling time. Higher ambient temperature or humidity, the cooling rate will slow down, the cooling time grows accordingly. 6.

6. Cooling system design: the cooling system design of the mold has a direct impact on the cooling effect. Reasonable cooling channel layout and cooling medium flow rate can effectively improve the cooling efficiency and shorten the cooling time.

7. Experimental and empirical data: In practice, it is often necessary to adjust and determine the optimal cooling time through experiments and accumulated empirical data. The cooling time setting can be gradually optimized through quality inspection of products under different conditions.