What Is a Hot Runner Mold?
Knowledge

What Is a Hot Runner Mold?

Hot runner technology is an advanced technology being applied to the runner systems of plastic injection molds. Hot runner process are still in the development stage of plastic injection molding technology.
Published: Apr 25, 2022
What Is a Hot Runner Mold?

What Is a Hot Runner?

During the plastic injection process a “Hot Runner” ensures that the plastic passing through the runner stays molten by heating the runner. Temperatures along the entire runner, from the barrel outlet of the injection molding machine to the gate at the mold, are in a constant state of flux. By using heating rods and heating rings near the runner, a high-temperature state is maintained and the plastic in the runner is kept molten. Generally, between operation runs, it is not necessary to open the runner to take out the plastic after the machine is shut down. It is only necessary to heat the runner to the required temperature when the machine is turned on again. The production cycle of the hot runner mold is shorter than that of the traditional mold, which saves on raw materials. Today, hot runner molds have been widely used in industrial manufacturing.

What are Gates and Runners?

Runners are the tunnels molten plastic flow through to get to the mold. At the end of the runner is the gate which leads into the mold cavity. A hot runner mold is a mold in which the runners of a traditional three-plate mold are heated. Hot runner systems are divided into a fully hot runner and semi hot runner. The semi-hot runner has a simple hot runner structure on one side of the mold, is stable and easy to use, and has a low failure rate. Due to its simple structure, the maintenance cost is low, and the stability of production is more guaranteed.

The hot runner structure includes a manifold, a nozzle, and a temperature control box. A hot runner can be divided into open type (miniature semi-hot runner) and needle valve type (insulated runner). The hot nozzle directly determines the design of the hot runner system and how the mold is manufactured. A manifold is used when a mold has multiple cavities or multi-point feeding and is generally divided into standard and non-standard. Its structure is mainly determined by the distribution of cavities in the mold, the arrangement of the nozzles, and the position of the gates. The mold has a temperature control box for electronic control.

The Working Principle of the Hot Runner:

In the hot runner mold, the plastic raw material enters directly into the mold chamber rather than passing through a traditional cold runner which allows the runner to cool and solidify between each cycle.

Advantages of Hot Runner:

  • Shortens cycle time -
    The molding cycle of the part is shortened. Because there is no limitation on the cooling time of the runner system, the part can be ejected in time after it is formed and solidified. Many thin-walled parts produced with hot runner molds can have a molding cycle of fewer than 5 seconds.
  • Saves on plastic -
    There is no cold runner in the hot runner mold, so production and material costs are reduced.
  • Reduces waste -
    During the hot runner mold forming process, the plastic melt temperature is accurately controlled in the runner system. Plastic flows more uniformly into the cavities, resulting in consistent quality parts. The gate quality of the parts formed by the hot runner is good, the residual stress after demolding is low, and the deformation of the parts is small.
  • Production is automated -
    Elimination of subsequent processes is conducive to production automation. The product is finished when it leaves the mold, and there is no need to trim the gate and recycle the cold runner. Many foreign product manufacturers have combined hot runner and automation to greatly improve production efficiency.

Disadvantages of Hot Runner:

  • Higher initial costs -
    The cost of hot runner molds, as well as the components, can be significantly higher. For low volume production, the high overhead cost of mold tooling is the main reason hot runner molds are not more widely accepted.
  • High equipment requirements -
    Precision machining is required on the production process of hot runner mold equipment. The integration and cooperation requirements of the hot runner system and the mold are extremely strict. Lapses in quality could result in serious production process problems. Poor plastic seals could lead to plastic overflow and damage to hot runner components, interrupting production. If the relative positions of nozzle inserts and gates are not good, a serious decline in product quality could result.
  • Complex operation and maintenance -
    Compared with cold runner molds, hot runner molds are more complicated to operate and maintain. Improper use and operation can easily damage hot runner parts, making production impossible and causing huge economic losses. For new users of hot runner molds, it may take a long time to accumulate experience.
Published by Apr 25, 2022 Source :kknews

Further reading

You might also be interested in ...

Headline
Knowledge
Motion Control Systems in Factory
Motion control encompasses every technology related to the movement of objects. Motion control is also referred to as Servo Control or Robotics and is implemented in industrial processes to move specific loads in a controlled way. It is the core technology of factory automation and is the real-time management of the position and speed of mechanical moving parts according to the expected motion trajectory and specified motion parameters.
Headline
Knowledge
What is Rapid Tooling Molding Technology?
Rapid molding technology is a fast, convenient, and practical mold manufacturing technology. It is especially suitable for the development and trial production of new products, process verification, and functional verification, as well as multi-variety and small batch production.
Headline
Knowledge
The Mother of Machinery - Overview of Machine Tools
Life is full of inventions that provide convenient services and entertainment: mobile phones, MRTs, notebooks, computers, cars, etc. These exquisite finished products presented to consumers are all processed by a series of complex processes and assembled. Among them, in the industrial process of the product, the machine tool has a very critical position, without it, it is impossible to produce equipment and parts, so it has won the title of "The Mother of Machinery". However, despite its important role, it is little known. Therefore, in this article, we will expose the state of the machine tool industry, understand its contribution to the manufacturing industry, and extend the visible development in the future.
Headline
Knowledge
The Principle and Difference Between Punching and Blanking Die Processing Technology
Blanking is a punching piece used as a blank on the plate. Punching is punching round holes on the workpiece, and it can be performed simultaneously with blanking.
Headline
Knowledge
Anode Material Technology and Application in Lithium Batteries
The negative electrode material refers to the raw material that constitutes the negative electrode in the battery. The negative electrode of lithium-ion battery is made of negative electrode active material carbon material or non-carbon material, binder and additive to make paste glue, which is evenly spread on both sides of copper foil, dried and rolled. The key to the successful fabrication of lithium-ion batteries lies in the preparation of negative electrode materials that can reversibly de/intercalate lithium ions.
Headline
Knowledge
Do You Know About Drilling Machine?
Drilling machine is a general-purpose machine tool with a wide range of uses, which can process parts such as drilling, reaming, flat plane and tapping. When the drilling machine is equipped with process equipment, it can also carry out boring, and when the drilling machine is equipped with a universal worktable, it can also carry out drilling, and reaming.
Headline
Knowledge
Introduction of the Broach
The so-called broach refers to the order of size, the rough cutter and the fine cutter. Most of the cutters are mainly installed on the broaching machine, which is called the broach. Broach is a forming tool used for broaching. There are multiple rows of cutter teeth on the surface of the cutter, and the size and shape of each row of cutter teeth increase and change sequentially from the cutting end to the cutting end. When the broach makes a broaching motion, each tooth cuts a certain thickness of metal from the workpiece, and finally obtains the required size and shape.
Headline
Knowledge
The Three Key Enterprise Applications of Edge Computing Are Closely Related to Cloud, Industrial Internet of Things, and 5G
Edge Computing is a distributed network architecture that allows data to be processed and analyzed closer to its source, moving resources such as computing, storage, and network bandwidth as close to users (or endpoints) as possible. Industrial Internet of Things (IIoT), artificial intelligence, big data analysis to 5G networks, edge computing can be said to be the expansion and extension of IT environments and computing technologies that seek common ground in differences.
Headline
Knowledge
What is a Five-axis Controller?
The five-axis controller is the core of the five-axis processing machine, which is used to control the trajectory of the five-axis simultaneous motion and the compensation of the motion.
Headline
Knowledge
What is Laser Cutting and Uses?
There is more than one type of laser cutting. It can use different medias to generate lasers of different wavelengths, so the scope, characteristics and functions of the applications are different. In the following, the article will take you to understand the uses of laser cutting in different fields, so that you can better understand the laser cutting technology.
Headline
Knowledge
What is a Metal Shredder? Used in the Steel Industry to Manufacture Scrap Steel Resources
With the rapid development of the iron and steel industry, the iron steel industry has gradually shown contradictions such as insufficient natural resources, excessive energy consumption per ton of output, and environmental pollution. As the second mining industry of the iron and steel industry, scrap steel resources have the advantages of saving energy, reducing pollution, protecting the environment, recycling, etc., and its influence will be increasing.
Headline
Knowledge
What is A Punch? Introduction of Punching Principles, Types and Materials
A punch, also known as a punch press, is a forming process technology. There are many kinds of it. Due to different structural principles, the price and processing effect will change in response, but they all have the same structure. With the rapid development of the stamping industry, competition in all walks of life has increased. "Punches are also used in various industries, such as aerospace, education, auto parts, diving equipment and so on.
Agree