The cold runner that injects the Pet Preform mold refers to the portion between the mold inlet and the gate. The molten plastic maintains fluidity in the flow path due to the injection pressure and its own heat. However, as part of the molding material, the runner is not a product. Therefore, when designing the mold, we not only need to consider the filling effect, but also need to consider the material saving effect caused by shortening or reducing the flow path; but in fact, it is difficult for us to balance the two, which is why we need hot runner mold
Also known as a no-runner system, a hot runner is a system in which molten plastic does not solidify after each injection, so that when the plastic part is released, the gates in the flow path need not be released. Because the plastic in the flow channel is not solidified, the flow path remains clear the next time the injection is made.
1. Advantages of hot runner molds compared with cold runner molds
Why did you develop a hot runner system? What benefits can the hot runner system bring to us? Engineers familiar with plastic injection molding processes know that traditional injection molding is always accompanied by the following disadvantages:
Difficult to fill; b. Thin-walled large-size parts are easily deformed; c. Material waste in the flow path; when using multi-cavity molds, the quality of plastic parts is inconsistent, and so on.
The advent of hot runner systems provides a near-perfect solution to these problems. In general, hot runner systems have the following advantages:
■ Shorter cycle time
Due to the limitation of the cooling time of the runner, the plastic parts can be discharged in time after molding and curing. For the production of thin-walled small parts, the molding cycle can be kept within 5s.
In a complete hot runner mold, the material is not wasted because there is no cold runner. This has greater implications for the application of more expensive plastic materials. In fact, in the era when the world’s crude oil and raw materials were expensive, the world’s major hot runner manufacturers witnessed a leap-forward development. This is because hot runner technology is an effective way to reduce waste and thereby reduce the cost of raw materials.
■ Reduce defective products and improve product quality
During hot runner injection molding, the temperature of the molten plastic in the runner system can be precisely controlled so that the plastic can flow into each cavity in a more consistent manner, thereby ensuring consistent product quality. The quality of the hot runner gate is higher, so after demolding, the parts produced will have less internal stress, resulting in smaller part deformation. Therefore, many high quality products on the market are produced using hot runner molds.
■ Eliminate the following steps to help with production automation
Once molded with a hot runner mold, the part becomes the final product, so there are no next steps, such as gate dressing, recycling, and runner cooling, to help with production automation. Many manufacturers at home and abroad have combined hot runner systems with automation to greatly increase production efficiency.
2, hot runner type
Advantages of the valve hot runner include:
Shorten production cycle and increase production efficiency;
Since the cold runner is replaced, there is no cold slug, which saves a lot of raw materials;
Improve product consistency without obvious gate marks;
Significantly improve the appearance of the product;
Helps reduce product stress, minimize product distortion and structural brittleness, thereby increasing the productivity and life cycle of complex products;
Provide more process control, allowing precise adjustment of the injection molding process;
Not limited by changes in plastic injection molding materials.
Choosing Jilian Plastic Mould, we are a China Pet Bottle manufacturer with rich experience. We can design reasonable and efficient products according to your actual situation, let you spend the least time to harvest the highest quality products and the most intimate service. . If you are heartbeat, come and contact us!