The following are four paragraphs about "How to ensure the uniformity of the wall thickness of the preform in the design of PET bottle preform mold":
1. Reasonable mold structure planning
At the beginning of the design of PET bottle preform mold, the mold structure needs to be carefully planned. The design of the runner system is crucial to ensure that the molten PET material can flow into the cavity smoothly and evenly. Reasonably design the size and shape of the main runner, branch runner and gate to avoid the situation where the material flow rate is too different. For example, a gradual runner design is adopted to gradually accelerate or decelerate the material during the flow process, thereby reducing the uneven wall thickness caused by sudden changes in flow rate. At the same time, the location of the gate should be selected at a suitable position of the preform, generally close to the central area, to ensure that the material can be evenly diffused from the center to the surrounding area, laying the foundation for the uniformity of the wall thickness of the preform.
2. Accurate temperature control system
Temperature has an important influence on the fluidity and molding effect of PET materials. Set up a precise heating and cooling system in the mold to ensure that the mold temperature remains stable and uniform throughout the molding process. The heating system can make the material reach the appropriate melting temperature before entering the cavity, avoiding uneven wall thickness caused by poor fluidity due to too low temperature. The cooling system should quickly and evenly take away the heat to prevent local overheating or overcooling. By rationally arranging the cooling water channel, the cooling effect is evenly distributed throughout the mold cavity, ensuring that the preform shrinks evenly during the cooling process, thereby ensuring the consistency of the wall thickness.
3. Optimization and adjustment of material flow
During the injection molding process, adjust parameters such as injection pressure, speed and time to optimize the flow state of the material. Appropriate injection pressure can ensure that the material fully fills the cavity and avoid uneven wall thickness caused by problems such as short shots. Control the injection speed so that it is neither too fast nor too slow during the filling process. Too fast may cause material turbulence, and too slow may cause the material to cool too early. At the same time, according to the shape and size of the preform, reasonably set the holding time and pressure to compensate for the shrinkage of the material during the cooling process and further improve the uniformity of the wall thickness of the preform.
4. Strict quality inspection and feedback
After the design is completed, a strict quality inspection system should be established in the actual production process. We use advanced measuring equipment, such as three-coordinate measuring machines, to accurately measure the wall thickness of the preforms. We promptly detect uneven wall thickness and adjust the mold design and process parameters based on the test results. At the same time, we continuously optimize mold design and production processes through the collection and analysis of production data to ensure that the wall thickness of the preforms is always uniform during the long-term production process.
