This article mainly decribes about Stack Mold Technology & Application in plastic injection molding.
What is Stack mold?
Stack mold can be described as a mold assembly consisting of a series of single-face molds of the same size, mounted back-to-back or “stacked” next to the other. Without increasing the plastic injection molding machine platen size or tonnage, stack molds double (or more for increased stack mold levels) the output of standard plastic injection molds, increasing molding efficiency and reducing the overall part cost. Stack molds can also produce multi-component assemblies or a family of parts in one shot on one plastic injection molding machine.
Most stack molds have an equal number of the same cavities in each side of the mold, or parting surface, but they can also have different cavities in each mold parting surface to produce a family of parts per shot, with each part being a different shape and size.
Optimal Molding Efficiency and Improved Automation
Stack mold allows to manufacture different sizes or geometry in one shot on one plastic injection molding machine, saving machine and labor cost. Enhance the output of a given molding machine, providing immediate production and part cost savings
Doubled Part Production
Comparing to standard mold, stack mold clamping force only increases by 10%～15% but productivity could increase by 90%～95%. Instead of increasing the mold size by adding more cavities, a stack mold maintains mold size and machine size by adding a second layer of cavities parallel to the first layer. The fill, pack and cooling time remain the same for a stack mold and only the mold open and mold close time will add slightly to the cycle time.
Reduced Production and Part Cost.
The part price is determined by the machine hour rate, which is directly related to the machine clamp tonnage. A stack mold requires only about half the clamp tonnage than a single-face mold with the same number of cavities.
Stack Mold Applications
Stack mold technology offers greatest advantages for plastic injection molded parts that do not require large mold opening strokes. It is widely used in a wide range of applications , some of which includes:
Consumer products, such as toilet seat
Plastic packaging, such as Thin wall lids,containers, closures and caps