What are the characteristics of the reflow ratio of PET injection molding machine?

Reflow ratio is an important parameter in the plastic injection molding process, especially playing a key role in the operation of PET injection molding machines. The backflow ratio refers to the ratio between the screw retraction distance and the feed amount. It is usually used to control the movement of the screw during the injection process. In PET injection molding machines, the reflow ratio has some characteristics, which will be analyzed in detail below:

1. Control the melting state of plastic: Adjustment of the reflow ratio can affect the retraction distance of the screw, thus changing the time the molten PET material stays on the screw. A smaller reflow ratio means that the distance the screw retreats is smaller, and the PET material stays on the screw for a shorter time, which may cause the PET material to be insufficiently melted. On the contrary, a larger reflow ratio will increase the residence time of the PET material on the screw, which will help the PET material to fully melt.

2. Control the stability of the injection process: An appropriate reflux ratio can ensure the stability of the injection process. If the reflux ratio is set too large and the screw retreat distance is too long, it may cause too many plastic columns to form in the barrel, affecting the stability of the injection process. If the reflow ratio is set too small, the air in the barrel may be compressed, affecting the quality of the molded product.

3. Affects the appearance and quality of the product: The reflow ratio directly affects the appearance and quality of the molded product. A reflow ratio that is too large may cause defects on the surface of the molded product, such as bubbles, flow marks, etc.; while a reflow ratio that is too small may result in insufficient surface finish of the molded product, and even affect the density and strength of the product.

4. Suitable for different molded product requirements: The choice of reflow ratio depends on the specific molded product requirements. For some molded products that require higher surface quality, the reflow ratio can be appropriately increased to ensure that the PET material remains on the screw for sufficient time, making the surface of the molded product smoother. 

5. It needs to be optimized according to specific process parameters: the setting of the reflow ratio needs to comprehensively consider the influence of other injection molding process parameters. For example, changes in parameters such as injection speed, injection pressure, and holding time will all affect the selection of the reflow ratio. 

6. Pay attention to the performance and stability of the equipment: The setting of the reflow ratio also needs to take into account the performance and stability of the injection molding machine equipment. An excessively large reflow ratio may exceed the load-bearing capacity of the injection molding machine, leading to equipment performance degradation or failure, while an excessively small reflow ratio may affect the stability and production efficiency of the injection molding machine.