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Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Zhang, Chao

Abstract

The Plastic Injection Mold (PIM) industry has been searching for new technologies that improve the manufacturing of parts by reducing the production time and cost as well as increasing the quality of the product. The cooling systems in the PIM are designed initially to be straight-drilled into the mold, but this manufacturing process has traditionally not been very effective, since for molded parts with complex geometries, the cooling channels are not able to reach certain areas. This limitation has led the industry to develop conformal cooling channels that use the additive manufacturing technology, which allows the cooling channels to conform the part’s working surface. So, the production cycle time can be reduced and the temperature distribution in the molded part is more uniform to provide better quality in the product. That said, the cost of using conformal cooling in the manufacturing process has been demonstrated to be higher than the cost of conventional cooling channels Therefore, this research aims to investigate the advantages of conformal cooling and the degree to which it improves product quality and manufacturing cycle time. To be able to carried out these studies, CFD simulations using NX-FLOEFD by Siemens are performed to investigate the possibilities of improve conventional cooling channels, and then to compare them with a designed conformal cooling channel. The parametric studies are performed for different configurations and different operating points to improve these systems. A conformal cooling system is designed in this study for the same product part following design recommendations from previous studies. The study indicates that the conformal cooling channels proven to have a better cooling performance providing a higher quality product.

Summary for Lay Audience

Plastic Injection Molding tools have been developed in the industry for the manufacture of plastic parts and pieces used in the diverse fields. The process followed to create the product starts with the injection of the melted plastic into the tool followed by the solidification of the part, due to the cooling system inside of the cavity and core of the mold, until the expected temperature. 80% of the cycle time of this process is consumed by the cooling system, so its improvement will reduce the cycle time and this will reduce the production time and cost. For this reason the design of the cooling systems in these tools is of importance.

These cooling systems developed in the mold industry have been manufactured by the straight-drilled process, which for complex geometries, it has not been the most effective design. This limitation has led the industry to develop conformal cooling channels which use additive manufacturing technology to conform the channels to the part's working surface, providing a reduction of the cooling time and a better quality of the product. The additive manufacturing technology have been demonstrated to be higher than the cost of the straight-drilled process and for this reason it has been totally implemented in the industry. This research aims to investigate the advantages of conformal cooling system over conventional cooling and the improvements of the product quality as well as the manufacturing cycle time. Computational Fluid Dynamic (CFD) using NX-FLOEFD by Simens to obtain the most optimal configuration using conventional cooling channels in the mold, to then compare them with a designed conformal cooling system in the same tool. Parametric studies are also generated for the different configurations and operating points in the search of the most optimal configuration for the purposes of reducing the cycle time while maintaining the expected quality of the product.

The study indicates that the conformal cooling channels proven to have a better cooling performance providing a higher quality product.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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