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How to choose a high quality hot runner and high quality manufacturer


Hot runner technology, with its saving cost, shorten the molding cycle and other unique technical advantages, plastic injection molding process has become an important direction of development. In European and American countries, most of the injection molding production depends on the hot runner technology, but in China, the use of this advanced technology companies are less and less. However, with the further development of China's mold industry, this technology will be gradually extended and widely used, so how to choose the appropriate hot runner system?
Those cases can be directly used in hot runner systems
Injection pressure
Injection pressure loss in hot runner system can not be ignored. Many hot runner mold users have a misunderstanding: located in the hot runner is always hot, so the injection pressure loss of hot runner is much smaller than the cold flow channel. Actually otherwise, in order to meet the needs of hot runner structure design, soluble body in the hot runner system flow distance will be greatly increased, so hot runner system in the injection pressure loss also is not a small glimpse. In practical application, because of the large injection pressure loss caused by hot runner system, the difficulty of injection molding is many, so the CAE software is used to analyze and calculate the flow of plastic (such as PC, POM, etc.), which is used in hot runner system.
    Heating mode
One main difference between the hot runner system is the heating mode of the material. The internal heating system is the heater directly installed in the melt, from the internal heating raw materials. External heating system is in the external heating raw materials, so that the raw material in the absence of obstacles to flow through the flow channel. The external heating system solves the problem of dead melt channel, and the shear melting curve in the more reasonable. Gate type
There are many types of gates for selection. The factors to be considered include: allowing the gate mark, gate location, and the type of material for injection molding. Both the non crystallization, the crystallization or the thermoplastic elastomer, the different gate types all have the limit to the specific material. Understanding the most suitable material for the use of the gate can help select the best gate.
   Standard or not
Under normal circumstances, the hot runner system supplier to provide standard and non - quasi - standard two kinds of hot runner system. Then, the user should choose the standard hot runner system, including the standard length and the standard size of the nozzle, hot runner plate, gate insert, etc.. This is not only because the standard hot runner system is low price, delivery time is short, and parts are interchangeable, for future use and maintenance. Once one of the parts is broken, the other one is fitted with another.
Types of processing plastics
When choosing a hot runner system, the type of plastic to be processed must be considered. For example, if the processing of glass reinforced plastics (such as glass reinforced nylon material, etc.) should be used to choose the good wear resistance of the gate inserts; if the processing easy thermal decomposition of plastic (such as PVC) should be used to open, no flow dead heat flow path system; if the processing flow of the plastic material (such as PC) should consider the use of larger nozzle series, and in the hot runner plate, the use of large size, etc..
Weld size
In order to guarantee the best system performance, it is necessary to analyze the plastic parts and processing conditions. Therefore, it is not only to consider the weight of the product, but also to calculate the appropriate size of the weld, including melt flow index, injection time, injection cycle and melt temperature. The suitable size of the weld is very important to the heat flow path. The size of the weld can lead to the degradation of the plastic, or the uneven or incomplete filling of the plastic parts, and the color change is slow. In order to determine the optimum size of the weld, the pressure drop, the residence time, the Wen Sheng, the shear velocity, the color frequency and other factors need to be considered.
Multi zone temperature control
If the user needs a large size, complex heat flow system, or processing temperature sensitive, processing parameters of the narrow range of plastic, it should choose a hot runner design scheme with multi area, respectively. Such users can adjust and control the temperature distribution according to the need of temperature distribution. An ideal hot runner system should have uniform temperature distribution, but in fact there are many reasons to lead to different temperature of the hot runner system, such as the quality of the hot runner heating module, the heat flow path system and the mold, the heat loss, the plastic solution in the hot runner and the different shear heat. Hot runner system size becomes more complex, the more you should choose a hot runner system of multi zone temperature control