In the production process of high-quality PVC baseballs, it is necessary to control the key points of raw materials, molding, post-treatment and other links.
In terms of raw materials, it is necessary to strictly control the quality of PVC resin, select resin with an appropriate degree of polymerization, and ensure that it meets the performance requirements of the product. At the same time, precisely control the addition ratio of stabilizers, plasticizers, fillers and other additives. The types and addition amounts of additives will affect the product’s weight, flexibility, stability and other properties.
In the forming process, mold design is of vital importance. It is necessary to ensure that the dimensional accuracy of the mold is high, and the dimensional tolerance is controlled within a very small range. At the same time, the position and size of the gate should be reasonably designed to enable the PVC melt to flow smoothly and evenly into the mold cavity, avoiding insufficient or excessive local filling. It is also necessary to set up exhaust grooves inside the mold to promptly discharge the gas inside the mold, preventing problems such as bubbles and material shortage in the product caused by gas residue. During the injection molding process, parameters such as injection pressure, injection speed, holding time and cooling temperature need to be precisely adjusted. Too low injection pressure can lead to insufficient melt filling, while too high pressure may cause the melt to overflow from the mold. If the injection speed is too fast, it will cause turbulence in the melt within the cavity; if it is too slow, the melt will cool down too quickly. Insufficient holding time and pressure can cause the baseball to contract and dent, while too long or too high pressure may lead to the generation of internal stress. The cooling time and temperature will affect the crystallinity and shrinkage rate of PVC material, and thus influence the dimensional accuracy and roundness of the product.
In the post-processing stage, the scraps and waste products generated during the production process are recycled and reused. After undergoing crushing, cleaning, drying and other treatments, they are reused as raw materials, which can reduce costs and minimize resource waste. Meanwhile, according to the product requirements, heat treatment correction methods can be adopted to eliminate internal stress and improve roundness. However, it is necessary to pay attention to controlling the temperature and time of heat treatment to avoid product deformation or performance degradation due to excessively high temperature or long time. For defects such as burrs and flash generated during the injection molding process, mechanical processing or manual trimming methods should be adopted to remove them. During the trimming process, the force and precision should be controlled to avoid secondary impact on the roundness of the product.