Views: 0 Author: Site Editor Publish Time: 2025-08-14 Origin: Site
1. The melt flow balance is good, reducing product warping and deformation
The square box and square lid molds belong to typical thin-walled structures. The three-point injection method distributes three injection ports around the mold cavity, allowing the melt to be filled synchronously from three directions towards the center and edges of the cavity. Compared with the problems of uneven filling and large differences in cooling shrinkage caused by a long melt flow path in single point injection, three-point injection can significantly shorten the flow distance of the melt in the mold cavity, reduce pressure loss and temperature gradient in different areas, and thus reduce the warping and deformation of the product caused by internal stress concentration. In actual production, the square boxes and lids produced using this mold have high edge flatness, and the fit gap between the lid and the box body can be controlled within 0.1mm, meeting the sealing requirements of the lunch box mold.
2. Improved molding efficiency, suitable for mass production
Thin walled lunch boxes require high injection molding speed and pressure. Three point injection molding can increase the melt filling rate and shorten the single molding cycle by simultaneously feeding multiple injection ports under the same injection molding pressure. For example , square boxes with a wall thickness of 0.4-0.8mm , the filling time of three-point gluing can be shortened by 20% -30% compared to single point gluing, greatly improving the production capacity per unit time and meeting the demand for large-scale production of food box products.
3. Improve material utilization and reduce plastic box/lid production costs
Under the three-point injection method, the melt flows more evenly in the mold cavity, which can reduce the scrap rate caused by insufficient filling. At the same time, due to the shortened flow path, the pressure transmission during the holding stage of the injection molding process is more balanced, and the deviation of the product wall thickness is smaller, which can further reduce the wall thickness and raw material consumption while ensuring strength. In addition, although the total volume of aggregate from the three inlet ports is greater than that of single point inlet ports, compared to multi-point inlet ports (such as four or more points), the labor or equipment costs for subsequent inlet ports are lower, and the comprehensive material and processing costs can be reduced by 5% -8%.
In summary:
In the production of square boxes and square lid (lunch boxes mold), three-point injection molds have the advantages of balanced melt flow, high molding efficiency, and high material utilization. By optimizing gate design, improving mold processing accuracy, and strengthening process parameter management, the advantages of three-point injection molding are maximized to achieve high-quality and high-efficiency production of thin-walled lunch box products.
