In the modern injection molding industry, stack mold technology (Stack Mold) is increasingly adopted by manufacturing enterprises as an efficient plastic injection molding solution. It is also known as stacked molds or multi-level molds. By stacking multiple parting surfaces within the same mold set, it enables the production of multiple parts in a single injection cycle, significantly improving injection molding production efficiency.
The working principle of stack molds is simple yet highly effective: Traditional injection molds have only one parting surface, whereas stack molds feature multiple mold layers stacked in parallel (typically 2 layers). Molten plastic is simultaneously injected into the cavities of each layer. When the injection molding machine clamps, all layers form parts at the same time; during mold opening, products from each layer are ejected synchronously. This innovative design achieves doubled (or even multiplied) output without significantly increasing the machine’s clamping tonnage. It is particularly suitable for producing thin-walled parts, small multi-cavity components, and flat plastic products.
The core advantages of stack molds are remarkable: Compared with conventional single-face molds, the required clamping force increases by only 5%-15%, while output can rise by 90%-100%. This directly reduces per-part production costs, shortens delivery cycles, and minimizes equipment footprint. Additionally, stack molds support multi-material co-injection (such as 2K stack molds), delivering high precision and excellent surface quality. They perfectly meet the demands for high productivity and low energy consumption in industries such as automotive, medical, packaging, and electronics.
In practical applications, stack mold technology is widely used for high-volume production of thin-walled parts, including automotive door panels, turnover crates, electronic housings, bottle caps, and containers. For example, in a high-end automotive interior or door panel stack mold project, production efficiency can increase by nearly 100%, delivering significant economic benefits to the enterprise and fully demonstrating the value of Stack Mold in modern injection molding processes.