I. The difference of mold structure in the molding of super-large plastic products, only the use of hot runner to make the plastic flow balance. For example, in the production of automobile lining, home appliance shell and other components, it needs more places to feed glue at the same time or in chronological order. At this time, hot runner is required to complete this step successfully. In addition, when the injection molding machine is deviated from the center of the injection molding machine to carry out lateral glue feeding, the hot runner feeding method can make the structure of the mould simple, at the same time make the molding easier, accelerate the forming speed, reduce the forming time, and produce no material head. Generally speaking, when three plates are used for injection, the heavy mother template needs to slide on the guide post. Even the new mould can not bear the heavy load caused by the sliding for a long time, so the die life is not long. In addition, in this way, the amount of template movement needed to remove the runner material from the mold is larger than that required for the removal of the molding product from the mold at each ejection.
Therefore, it is usually necessary to use a hot runner when the following conditions are encountered: 1. A longer vertical channel is required for the ejection side of the glue; 2. In order to avoid the problem caused by too long head; 3. Molding of large or eccentrically gelled products; 4. In the use of the three-board die, the mother template needs to be moved to remove the head. If hot runner molding is used, the movement of the opening die can shorten the moving distance of the unloading head. Therefore, a large forming machine is needed to produce the three plate die when cold runner is used, and a small forming machine can be used after the hot runner is used. 5. For materials with such characteristics as high viscosity, low viscosity or high forming temperature, hot runner system can be used to solve the problem of difficult forming. For example, in metal powder, ceramic powder, plastic magnet, plastic bearing and thermoplastic rubber injection molding, etc.
II. Save plastic 1. Using the traditional cold runner, there will be a cold head, resulting in additional costs. For example, if the head of the cold material accounts for 68% of the waste rate (only 320 g of the product can be produced at the time of manufacture of 1 kg of the material, the remaining 680 g is the head of the cold material, although the head of the cold material is still recyclable, However, due to the influence of factors such as human factors and mixed ratio of recycled materials, in order to maintain normal operation, it is necessary to accumulate some cold material heads, resulting in the retention of funds. 2. Hot runner can be used in high speed injection molding field. High-speed injection molding not only improves the efficiency of molding, but also is necessary to control the wall thickness of products such as cups and containers. 3. Used in laminated die. For products with thin walls and large quantities, such as CD casings, an increase of only 15% is required to increase production by 80% at the same injection time.
III. The environmental protection and efficiency of hot runner do not produce "garbage", so there is no problem of disposal of "waste". "garbage" means a waste of resources, while the hot runner system is a low carbon product, and it does not produce any harmful factors to the environment. Because there are many kinds of plastics and they are often different in color and color, it is necessary to classify and dehumidify, dry and seal the material heads in the injection molding process. At the same time, the noise generated by the shredding can also have a negative impact on the environment. To sum up, the application of hot runner in the injection mold has the following advantages: 1. The material head is easy to take out, and can reduce the stroke of the material head out; 2. When injection, plastic flow is more average, but also can control the operating conditions of each injection point, making plastic injection easier; 3. The cost of plastic material and labor are saved.