During the injection molding process of TPR raw materials, for various reasons, sometimes TPE materials may not flow uniformly and solidify in the mold, resulting in protrusions or bulges on the surface or inside of the product. The appearance of bulging not only affects the aesthetics of the product, but may also have a negative impact on the sealing, strength and other performance of the product. Do you know what to do if TPR raw materials bulge during the injection molding process? Below, the editor of Lishu will introduce to you:
TPR raw materials
Possible reasons for bulging of TPR raw materials during injection molding process:
1. Material overheating
During the injection molding process, if the TPR raw material overheats, it will enhance its fluidity, but at the same time, it will also make it prone to producing bubbles and uneven shrinkage. When TPR raw materials flow in the mold, if the temperature is too high, it will cause local excessive expansion and form bulging.
2. Excessive materials
Excessive injection of TPR raw materials into the mold is also an important reason for the bulging phenomenon. Excessive material can cause an increase in pressure inside the mold cavity, resulting in uneven distribution of TPR raw materials in the mold and the formation of local protrusions or bulges.
3. Mold design issues
The unreasonable design of the mold is also one of the reasons for the bulging phenomenon. The design of the mold's wall thickness is too thin, and the design of the cooling system is unreasonable, which can lead to uneven solidification of plastic in the mold and the formation of bulges.
4. Improper stamping process
Improper stamping process is also an important factor leading to bulging phenomenon. During the stamping process, if the parameters such as pressure, speed, and stroke are not set properly, it can lead to uneven plastic flow in the mold, forming bulges.
5. Improper pressure release
During the injection molding process, improper pressure release can also lead to bulging. Before opening the mold, if the pressure is released too quickly, it can cause the plastic to experience sudden pulling force in the mold, forming bulges.
Measures to deal with bulging of TPR raw materials during injection molding process:
1. Control material temperature
To avoid bulging caused by material overheating, it is necessary to strictly control the temperature of TPR raw materials. During the injection molding process, the heating temperature and insulation time should be reasonably set according to the characteristics and requirements of TPR raw materials, to ensure that TPR raw materials maintain stable temperature and fluidity in the mold.
2. Precise control of injection volume
To avoid bulging caused by excessive injection of TPR raw materials, it is necessary to precisely control the amount of plastic injected into the mold. During the injection molding process, the parameters of the injection molding machine and the structural design of the mold should be reasonably set according to the size and shape requirements of the product, to ensure that TPR raw materials are evenly distributed and cured in the mold.
3. Optimize mold design
To avoid bulging caused by mold design issues, it is necessary to optimize the mold design. In the process of mold design, the flowability and curing characteristics of TPR raw materials should be fully considered, and the wall thickness, cooling system and other parameters and structural design of the mold should be reasonably set to ensure the uniform flow and curing of TPR raw materials in the mold.
4. Strictly control stamping process parameters
In order to avoid bulging caused by improper stamping process, it is necessary to strictly control the stamping process parameters. During the stamping process, parameters such as pressure, speed, and stroke should be reasonably set according to the size and shape requirements of TPR products, as well as the characteristics of materials, to ensure the uniform flow and solidification of TPR raw materials in the mold.
5. Gradually release pressure
To avoid bulging caused by improper pressure release, it is necessary to gradually release the pressure before mold opening. Before opening the mold, the pressure inside the mold should be gradually reduced to avoid sudden pulling force that may cause TPR raw materials to bulge.
In summary, it is the possible cause and corresponding treatment measures for the bulging of TPR raw materials during the injection molding process. Through these measures, the occurrence of TPE bulging during injection molding can be effectively avoided, thereby improving the quality and performance of the product.
