According to Kally Tong’s article “Injection Molds 101: Cold Runner vs. Hot Runner Molds” on LinkedIn, plastic injection molding, a groundbreaking technology since the late 19th century, still predominantly utilizes two types of molds: cold runner and hot runner systems. Each system offers distinct advantages and limitations, crucial for informed decision-making in plastic manufacturing.

Cold runner molds employ unheated runners to distribute molten plastic to mold cavities. In two-plate molds, runners remain attached to the final product, requiring a separate ejection process. Three-plate molds automatically separate runners from the molded part, facilitating recycling and reducing waste.

In contrast, hot runner molds utilize heated runners, maintaining consistent temperatures for superior flow control. With options like externally and internally heated systems, hot runners eliminate the need for separate runners, enhancing efficiency and reducing cycle times.

Understanding the nuances between cold and hot runner molds empowers manufacturers to optimize their plastic injection processes for specific applications, ensuring efficiency and quality in production.

Explore Paul Murphy Plastics’ expertise in optimizing extrusion processes here.

Photo and article with all rights reserved, courtesy of Kally Tong on LinkedIn