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China To Promote Hot Runner Mold Technology Long Way To Go
Sep 01, 2017

This paper describes what is the hot runner technology, the composition of the hot runner system, the scope of application, and the development of the technology in China.

China's mold industry in recent years, rapid development, according to incomplete statistics, to the end of 2002, China's total mold production enterprises more than 20,000, employing about 50 million people, mold annual output value of about 44 billion yuan, the annual number of mold exports Showing a growing trend. In the world, but also on the mold is a big country. However, as the mold industry inextricably linked to the hot runner system, in China's development is chilling.


    In China, if you do the polls. Ask someone what is mold? It is estimated that many people will tell you with their own point of view, but you have to ask what is the hot runner? It can be said that in addition to some people in the field of expertise, you can answer very few people, and even most people do not know for the hot runner, even the hot runner is used in which industry are not clear, so Reality for a mold country is really a sad. According to the plan, by 2005, China's mold product level will reach the international mid-90s level, automobile mold and other production will also enter the era of independent development, but for the hot runner system, China is still still in the early stages.


One, what is hot runner


Hot runner technology is used in plastic injection mold casting flow channel system is an advanced technology, plastic injection molding process is a hot direction. The so-called hot runner molding refers to the plastic from the injection nozzle to the gate of the plastic is always kept in molten state, each time in the mold does not need to cure as waste removal, retention in the casting system of the melt can be injected at the time of injection Cavity.


The ideal injection molding system should form a uniform density of components, free from all flow paths, burrs and gates. Relatively cold runner, the hot runner to do this, it is necessary to maintain the material in the hot runner of the molten state, will not be sent with the forming parts. The hot runner process is sometimes referred to as a thermal manifold system, or a flowless molding process.


Basically, the thermal manifold can be regarded as an extension of the barrel and the nozzle of the injection molding machine. The function of the hot runner system is to send the material to each gate of the mold.


Second, the hot runner technology advantages and disadvantages


So why is this hot runner technology appear? What are the benefits of hot runner technology? Familiar with the injection molding process friends know that conventional injection molding often have the following unfavorable factors: 1, filling difficult; 2, thin-walled large parts of the deformation; 3, runner raw material waste; 4, multi-cavity mold The quality of the injection molding is different.


Hot runner technology, the problem is to provide a more complete solution, in general, the use of hot runner has the following benefits:


1, save raw materials, reduce into.


2, shorten the molding cycle, improve machine efficiency


3, to improve the surface quality and mechanical properties.


4, do not have to use three-plate mold that can use the point gate.


5, can be economically to the side gate molding a single product.


6, to improve the degree of automation.


7, available needle valve gate control gate frozen.


8, multi-cavity mold injection of the same quality.


9, to improve the surface beauty of injection molded products.


However, each technology will have its own shortcomings exist, hot runner technology is no exception:


1, mold structure is complex, high cost, high maintenance costs.


2, boot a period of time will be stable technology, resulting in more expensive price.


3, the emergence of melt leakage, heating element failure, the product quality and production progress greater impact.


The third shortcoming above, it is important to note that these unfavorable conditions can be reduced by purchasing quality upper heating elements, hot runner plates and nozzles and carefully maintained during use.


Third, the composition of the hot runner system


1, hot runner board:


Hot runner manifold


Hot runner manifold


The main task is to constantly melt the melt from the main channel into the individual nozzles, the melt transfer process, the melt pressure drop as much as possible, does not allow the degradation of materials. Commonly used hot runner board in the form of: a font, H type, Y type, X font; structure with external hot runner plate and heating hot runner board two categories.


2, nozzle:


Hot runner nozzle


Hot runner nozzle



Hot runner mold according to the nozzle structure in different forms, types are similar, but the various manufacturers of processing technology and implementation methods are very different, which determines the hot runner system quality and price differences. Generally have open, needle valve and several other special forms.


Needle-type nozzle technology is more advanced, the advantages are:


A. In the product does not leave the gate mark, into the gate at the traces of smooth;


B. Can use a larger diameter of the gate, the cavity can be filled to speed up, and further reduce the injection pressure, reduce product deformation.


C. to prevent the phenomenon of the phenomenon of wire when the mold and salivation phenomenon;


D. When the injection molding machine screw back, can effectively prevent from the mold cavity in the anti-material;


E. Can be combined with sequential control to reduce product welds.


3, heating elements



Hot runner heating element


Hot runner heating element



The heating element is an important part of the hot runner system, and its heating accuracy and service life have great influence on the control of the injection molding process and the stability of the hot runner system. Generally have heating rods, heating rings, tube heaters, screw heaters (heating wire rod) and so on.


 4, thermostat


Hot runner thermostat


Hot runner thermostat



Thermostat is the hot runner system for the various locations of the temperature control of the instrument, from the bottom to the high-end respectively, off-bit type, integral differential proportional control and new intelligent thermostat and other types, according to the needs of users with other In-mold components are used together.


Fourth, which molds are suitable for use with hot runners


The above talk about the benefits of so many hot runner, then whether each mold can use hot runner? the answer is negative. In general, hot runner technology is only applicable to plastic molds, and not every plastic mold is suitable.


Fifth, hot runner technology in China


As an advanced injection molding technology, hot runner technology in Europe and the United States universal use can be traced back to the middle of the last century or even earlier, as early as December 1940, E.R.Knowles made a hot runner technology patent. In China, the real application of this technology is nothing more than what happened in recent years.


With the increasing use of hot runner technology, hot runner mold in the proportion of plastic mold will gradually increase. Because of the above-mentioned advantages of using hot runner technology molds, therefore, the application of hot runner technology in foreign countries to develop faster, many plastic mold factory produced more than 50% of the mold used hot runner technology, or even 80% Very obvious. Hot runner in the country has also been used for production, but the overall less than 10%, this gap is quite large, which means that the industry has a considerable market space exists.


In recent years, hot runner technology in China's gradual promotion, which is largely due to China's exports to Europe and the United States the rapid development of the company's exports. In Europe and the United States, injection molding production has been quite dependent on hot runner technology. It can be said that basically no mold using hot runner technology is now very difficult to export, which also caused a lot of mold manufacturers for the hot runner technology awareness of the change. But because many foreign imports of hot runner system prices are more expensive, a large part of the domestic manufacturers can not accept, so there have been some domestic commercial hot runner system components. This is a great advantage for the promotion of hot runner technology in China. However, although the hot runner technology has begun to promote, and some plant utilization rate of 20% or more, the general use of internal or external thermal hot runner device, a few units with the world's advanced level of difficult needle valve hot runner device, but the overall On the hot runner adoption rate of less than 10%, compared with 50 to 80% abroad, or far enough.


In recent years, the world's leading hot runner technology suppliers have been stationed in the Chinese market in various forms, or to establish a production base, or to find agents, or set up offices, or the establishment of subsidiaries, it should be said that the trend of China Mold industry, the rapid upgrading of technology has played a huge role. (South Korea's Yudo), SINO (R) (first sharp) and other brands in our country have a considerable influence; another headquartered in the Netherlands Synventive (the first), the United States and the United States, (Husky) has been committed to the popularity of hot runner technology in China for many years. The United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, (Anole) Hot Runner Technology Service Co., Ltd., a Sino-German joint venture established in Zhejiang Huangyan's production base, will also be a wholly-owned Asian operations center - Husky Shanghai Technology Center also has a strong hot runner to provide capacity; Built in the middle of this year, the product of its heating components will be all the leading technology company in Germany Anole products; At the same time, China's large number of emerging private enterprises are also aware of this area of unlimited business opportunities, have established hot runner manufacturers, which for It is of great significance to reduce the use cost of hot runner technology and its popularization and application. In general, China's local enterprises are currently able to provide most of the technology is still relatively junior, choose a small space, the quality of instability, the shortening of the problem of short-term problems often affect the downstream business of its products trust.


As mentioned earlier, hot runner technology in China's penetration rate is very low, the reason is multifaceted. Many mold companies and injection molding companies have a wait-and-see attitude to this technology, or even do not understand it, which is largely because of the hot runner supplier publicity is not enough. As a hot runner supplier, it is necessary for its end customers (injection companies) to understand that the use of hot runners is to help them profit, not only make their products more beautiful, raw materials are saved, more productive, but also can help Increasing the service life of the mold. In this regard, hot runner suppliers and mold companies as intermediate links have a lot of work to do; the other hand, is to teach customers the correct use of hot runner system. Many customers (including mold enterprises and injection molding enterprises) after the purchase of the hot runner, due to improper use, often burn the heating element and even the temperature controller, which in turn lead to product quality decline, heavy damage caused by mold damage, injection molding machine stop Turn and so on, so that customers will mistakenly believe that the hot runner is a bad thing. Therefore, in China to promote hot runner technology, customer propaganda work long way to go, so that injection companies to accept and really learn to use hot runner technology will be hot runner suppliers in the future the most important work.


Hot runner technology is widely used in plastic mold a major change. In the injection molding, it has a considerable number of unparalleled advantages, it can be said that with the further development of its technology mature and reduce the cost of manufacturing, hot runner technology will increasingly show its huge advantages. The development of hot runner components of the national standards, and actively produce cheap high-quality components, do hot runner technology promotion, is the development of hot runner mold key.