Precision ADM recently completed a conformal cooling mold project that developed an improved “Venturi Cup” for Melet Plastics. The project received funded from Canada Makes through its Metal Additive Demonstration Program. The goal of the project was to show how a mold optimized using additive manufacturing (AM) methods can increase quality and productivity.
“This project is an excellent example of how the Metal Additive Demonstration Program works,” said Frank Defalco Manager Canada Makes. “Learning about the capabilities offered by adopting AM is what will make Canadian industry more productive and conformal cooling is a key area that needs to be exploited.”
One of the major factors contributing to the deformation of molded plastic parts is a lack of uniform heat distribution throughout molds. Various areas of the final part created by a mold cool at different rates creating internal stresses and deformations.
Dale Kellington General Manager of Precision ADM stated, “conformal cooling applications continue to have a direct impact on part quality, cycle times and productivity of injection molded parts”
A warping defect was reported in the production of a “Venturi Cup” part manufactured by Melet Plastics Inc. for use in an AGCO-Amity JV air seeder. The goal was a reduction in the warping seen in the large rectangular section of the part. Proposed alterations included changes in material, wall thickness and coolant temperature, as well as an optimized mold for cooling produced by Precision ADM using additive manufacturing methods.
Using conventional mold design, coolant channels are required to be drilled as a separate operation but are restricted to a path of connecting straight lines. This restriction is the cause of non-uniform heat distribution that causes part deformation. Additive manufacturing methods can be used to create molds featuring a coolant channels that follow the contours of a mold, drastically improving heat distribution during cooling. This has the added benefit of eliminating the task of drilling cooling channels.
Dale added, “with software such as Moldex our engineers can simulate the injection molding process and demonstrate the beneficial cooling characteristics of conformal cooling molds for production”
The project showed significant results. This application of additive manufacturing showcases the complex subsurface geometries that are possible using the method. The use of the optimized mold together with a decrease in wall thickness resulted in a warpage reduction of 42%; an overall warpage reduction of 54% was achieved with all other alterations included.