Injection molding technology: Introduction of hot runner technology

hot runner history, present and future
    As an advanced injection molding technology - hot runner technology, the increasing use of the United States and Europe can be traced back to the mid-last century or even earlier. As the hot runner has many advantages, therefore, relatively fast development in foreign countries, many plastic mold factory produced more than 50% of the mold using a hot runner technology, part of the mold factory even more than 80%, while in China, this technology in the past years before they really get the promotion and application. As the industry continues to develop mold, hot runner in the use of plastic mold and gradually increase the proportion. But overall less than 10%, this gap is enormous.

    In recent years, hot runner technology in China gradually extended, largely because of the mold's exports to Europe and America brought rapid development. In the United States and Europe, has been dependent on the injection molding hot runner technology. It can be said, do not use molds hot runner technology is now difficult to export, which also caused a lot of hot runner technology for mold manufacturers consciousness changes.

    Because many foreign imports more expensive hot runner system, a large part of the domestic manufacturers can not accept, so there have been some domestic hot runner system components. This hot runner technology in China to promote a great advantage. Although hot runner technology has begun to promote, but some companies use rate of 20% or more, usually a simple tip Tsui, Tong Tsui. A few companies use the world's advanced level of difficulty needle-type nozzle, but the overall rate of adoption of hot runner less than 10% and 80% abroad, far from 50.

    Second, the principle of hot runner

    Cold runner mold is the gate between the entrance and part of the product. Plastic injection molding in the flow passage by the pressure and flow of its own heat to maintain the state, as the flow channel forming part of the material, but are not part of the product. So when we design the mold fill is necessary to consider the effect, but also to consider how by shortening, narrowing the flow channel to save material, the ideal is the case, but the practical application is difficult to achieve best of both worlds.

    Hot Runner, also known as non-flow refers to flow after each injection of plastic is not solidified, the mold plastic products will not flow in the outlet prolapse. Because plastic does not flow in solidification, so when the next injection flow is still smooth.

    Brief words, is the hot runner injection molding machine nozzle extension.III. The advantages of hot runner molds
    In today's world of hot runner molds industrial countries and regions have been very widely used. This is mainly because the hot runner mold has the following salient features:

    1, shortening the molding cycle parts

    Because there is no runner system cooling time constraints, can be promptly cured molding parts ejection. Many use the hot runner mold thin-wall parts molding cycle in 5 seconds or less.

    2, save the plastic raw material

    In pure hot runner mold cold runner failing, so no production costs expected. This is expensive for the application of plastic items especially significant. In fact, a major international manufacturer of hot runner in the world are oil and plastic raw materials, expensive years has seen rapid development. Because the hot runner technology is expected to reduce the cost effective way to reduce the cost of materials.3, to reduce product costs, improve product quality

    In hot runner molding process, plastic melt temperature in the flow system to be accurately controlled.Plastic can be more uniform state into the mold cavity, the result is consistent quality parts. Gate hot runner molding components of good quality, low residual stress after stripping, parts deformation. So many high-quality products on the market by the hot runner molds. MOTOROLA mobile phones such as the familiar, HP printer, DELL laptop computer with many plastic parts are made of hot runner molds.

    4, to eliminate the follow-up process is conducive to automation.

    The hot runner mold after molding parts for the finished product, and recovery processing without pruning gate cold runner processes. Conducive to automation. Many products of foreign manufacturers are combining the hot runner and automation to significantly increase productivity.

    5. Expand the application of bamboo mold around the injection molding process

    Many advanced plastic molding hot runner technology is developed on the basis of. Such as PET preform production, in co-injection mold multicolor, multi-material co-injection process, STACKMOLD and so on.

    IV. Drawback hot runner mold

    Although compared with the cold runner mold, hot runner mold has many significant advantages, but users also need to know about mold hot runner mold shortcomings. Summed up the following points.

    1, the mold costs

    More expensive components, hot runner, hot runner molds may be substantially higher cost. If the production of small parts, a high proportion of the cost of the mold tool, the economy does not take count. For many developing countries, die user, the price of your hot runner system is widely used in hot runner molds affect one of the key.

    2, hot runner mold production process equipment for high

    Hot runner molds need to be made to ensure precision processing machinery. Hot runner systems and integration and the mold with the extremely strict requirements, or die in the production process will be a lot of serious problems. Such as the plastic seal is not good cause damage plastics overflow interrupt production of hot runner components, nozzle inserts and the relative position of the gate leading to poor product quality, a serious decline and so on.

    3, operation and maintenance complex

    Compared with the cold runner molds, hot runner mold operation and maintenance complex. Easily damaged by improper operation such as the use of hot runner parts, so that production can not be, causing huge economic losses. Hot runner mold for a new user, you need a longer time to accumulate experience.

    V. hot runner system components

    Although the world there are many manufacturers and a variety of hot runner hot runner product line, but a typical hot runner system by following a few major components:

    1. Hot runner plate (MANIFOLD)

    2. Nozzle (NOZZLE)

    3. Temperature controller

    4. Auxiliary parts

    VI. Technical key hot runner applications

    A successful project requires the application of hot runner molds multiple links to be protected. One of the most important of the two technical factors. First, the plastic temperature control, the second is plastic flow of control.

    1. Plastic temperature control

    Application of plastics in hot runner temperature control is extremely important.Many production occurred during the processing and product quality

    Problem directly from the hot runner temperature control system is not good. Methods such as using hot needle injection molding product gate gate the problem of poor quality, method of forming the gate valve closed when the valve needle difficulties, multi-cavity mold filling time and the quality of parts and other inconsistencies. If possible should be chosen, respectively, with multi-zone hot runner temperature control system to increase the use of the flexibility and adaptability.

    2. Plastic flow control

    Plastic flow in hot runner system to balance. Gate to open the plastic while simultaneously filling the cavity. Weight for the part to the differences between the FAMILYMOLD runner size design balance. Otherwise there will be some parts filling packing enough, and some parts are over-filling packing, flash is too large and poor quality. Runner runner size design should be reasonable. Size is too small filling pressure loss is too large. Size too large, too large hot runner, hot runner system plastic stays in too long, damage caused by material properties after forming parts can not meet the requirements. The world has been designed to help users design the best flow of CAE software such as MOLDCAE.

    VII. The application of hot runner molds

    1. Types of plastic materials

    Hot runner mold has been successfully used for processing a variety of plastic materials. Such as PP, PE, PS, ABS, PBT, PA, PSU, PC, POM, LCP, PVC, PET, PMMA, PEI, ABS / PC and so on. You can use any cold runner mold plastic materials can be used hot runner mold.

    2. Part size and weight

    Hot runner mold parts with the minimum of 0.1 grams. Maximum of 30 kg. Wide range of applications flexibility.

    3. Industry

    Hot runner mold in the electronics, automotive, medical, daily necessities, toys, packaging, construction, office equipment and other industrial sectors have been widely used.

    Eight International Briefing on the hot runner mold

    Industry in the world, more developed countries extremely active hot runner mold. The increased proportion of hot runner molds. Small number of less than 10 people die factories for the production of hot runner molds. Overall in North America, Europe, use of hot runner technology, longer hours, more experienced in high level. In Asia, except Japan, Singapore, South Korea, Taiwan, Hong Kong leader. North America, Europe, although higher levels of mold, but the price is higher delivery longer. In contrast, Asian hot runner manufacturers on price and delivery more competitive. And China's hot runner mold is still in its infancy, but is growing rapidly, the ratio continues to increase.

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