What are the advantages of hot runner molds?
What is a hot runner?
Hot runner technology is an advanced technology applied to the pouring runner system of plastic injection hot runner molds, and is a hot direction in the development of plastic injection molding technology. The so-called hot runner molding means that the plastic sent from the injection machine nozzle to the gate is always kept in a molten state, and does not need to be solidified and taken out as waste every time the mold is opened. The molten material retained in the pouring system can be injected into the cavity during the next injection.
The ideal injection molding system should form a part with uniform density, unaffected by all runners, flash and gates. To achieve this, hot runners must maintain the material in a molten state in the hot runners and not be sent out with the molded part. The hot runner process is sometimes called a hot manifold system, or runnerless molding. Basically, the hot 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 in the mold.
- Advantages and disadvantages of hot runner technology?
What benefits can hot runner technology bring us? Friends who are familiar with injection molding know that conventional injection molding often has the following disadvantages:
- Difficulty in filling the mold.
- Deformation of thin-walled large parts.
- Waste of runner raw materials.
- The quality of injection molded parts of multi-cavity molds is different. The emergence of hot runner technology provides a relatively complete solution to these problems. Generally speaking, the use of hot runners has the following benefits:
- Save raw materials and reduce costs.
- Shorten the molding cycle and improve machine efficiency.
- Improve the surface quality and mechanical properties of products.
- Point gates can be used without using three-plate molds.
- Single products can be economically molded with side gates.
- Improve the degree of automation.
- Needle valve gates can be used to control gate freezing.
- The quality of injection molded parts of multi-cavity molds is consistent.
- Improve the surface aesthetics of injection molded products.
However, every technology has its own shortcomings, and hot runner technology is no exception:
- The mold structure is complex, the cost is high, and the maintenance cost is high. (We recommend that you follow the “Mechanical Engineer” public account to get the dry goods knowledge and industry information at the first time)
- It takes a while for the process to stabilize after starting the machine, resulting in a large number of waste products.
- When melt leakage occurs and heating element failure occurs, it has a great impact on product quality and production progress.
The third shortcoming above needs special attention. By purchasing high-quality heating elements, hot runner plates and nozzles and carefully maintaining them during use, these adverse situations can be reduced.
- What are the components of the hot runner molds system?
The hot runner is composed of four parts: hot runner plate, nozzle, heating element, and temperature controller.