JPS62207619A - Heating cylinder of injection molder - Google Patents

Abstract

PURPOSE:To realize the uniform temperature distribution throughout the whole hating cylinder and consequently make it possible to stably manufacture favorable injection molded items by providing a plurality of band heaters which are fitted through a heat transferring body onto a cylinder main body and arranged in the axial direction of the cylinder main body in such a manner as being separated from one another. CONSTITUTION:A tubular heat transferring body 10 made of copper alloy base material or the like having high heat conductivity is interposed between a cylinder main body 1 and respective band heaters 2. When the temperature difference develops between heating zones adjacent to each other by the difference between the set temperatures of the respective heating zones, heat transfer occurs through the heat transferring body 10 from the higher temperature side band heater 2 to the cylinder main body 1 in the lower temperature side heating zone within the cylinder main body 1 so as to make the temperature difference between both the heating zones smaller. As a result, the discontinuity on the temperatures among the heating zones is removed and the uniform temperature distribution is formed throughout the whole heating cylinder. Consequently, the stable manufacture of favorable molded items is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating cylinder for an injection molding machine, and in particular to a heating cylinder for an injection molding machine.
The present invention relates to a heating cylinder for an injection molding machine that provides a smooth temperature distribution along the axial direction of the heating cylinder.

Conventional technology 01 An injection molding machine is equipped with a heating cylinder in the injection device, and the injection molding material supplied from the hopper to the heating cylinder is heated by a heater on the outer periphery of the heating cylinder, and the screw is rotated to knead the injection material. I'm trying to melt it. In order to uniformly heat various injection materials to the required melting temperature within the heating cylinder, conventionally, as shown in Fig. 3,
A plurality of heating zones are provided in the axial direction of the heating cylinder, and a band heater 2 is provided on the outer periphery of the cylinder body 1 in each heating zone, and the temperature of each heating zone is detected by a thermocouple 3. Turn on and off the power supply to the cylinder axial temperature valve of the injection material in the heating cylinder.
The temperature is controlled to be optimal depending on the type of injection material. However, if the set temperature of each heating zone is set to different values in order to obtain the required temperature distribution, the fourth
As shown in the figure, the temperature is discontinuous between the heating zones, especially between the band heaters 2, and the injection material inside the heating cylinder is
When it reaches this discontinuity, it is inconvenient because it is suddenly heated or cooled. In order to solve this problem, it has been known to provide a large number of heating zones, but in this case, the temperature control system becomes complicated and the cost of the device increases.

Problems to be Solved by the Invention The present invention eliminates temperature discontinuities that tend to occur in the heating cylinder of an injection molding machine by using a simple device configuration, and creates a smooth temperature distribution of n over the entire heating cylinder. Obtain IT and stably produce suitable indexed molded products! The purpose is to provide a heating cylinder of 3fi injection molding.

Means for Solving the Problems The heating cylinder of the injection molding machine of the present invention has a cylindrical heating cylinder mounted on the outer peripheral surface of the cylinder body and made of a material having higher thermal conductivity than the material of the cylinder body. It has a configuration including a heat transfer body and a plurality of band heaters that are fitted into the cylinder body via the heat transfer body and are spaced apart from each other in the axial direction of the cylinder body.

The set temperature of each heating zone is determined and controlled to the set temperature so that the temperature distribution of the injection molding material in the working heating cylinder becomes appropriate depending on the molding material. When the set temperatures of each heating zone are different and a temperature difference occurs between adjacent heating zones, the temperature difference between the heating zones is generated through a highly thermally conductive heat transfer body interposed between the cylinder body and the band heater. Heat transfer is performed between the cylinder body and the band heater so that . As a result, thermal discontinuities between heating zones, particularly between band heaters, are eliminated.

Embodiment FIG. 1 shows a heating cylinder of an injection molding machine according to an embodiment of the present invention, and the basic structure of the cylinder is almost the same as the conventional heating cylinder shown in FIG.

In FIG. 1, a cylindrical heat transfer body 10 is tightly fitted on the outer peripheral surface of a cylinder body 1.
A predetermined number, for example, three conventionally known band heaters 2 are fitted into the cylinder body 1 via the cylinder body 1, and are spaced apart from each other in the axial direction of the cylinder body 1 in separate heating zones.

The heat transfer body 10 is made of a copper alloy material, such as a VI material, which has higher thermal conductivity than the constituent material of the cylinder body 1, such as an iron alloy material. In the figure, reference numeral 3 denotes a thermal lightning pair for each heating zone, which is connected to a temperature control system (not shown) together with each band heater.

Hereinafter, the operation of the heating cylinder configured as described above will be explained.

First, the set temperature of each heating zone is determined so that the temperature of the injection molding material in the heating cylinder is appropriate for the molding material, and as is known in the art, each heating zone is controlled by a temperature control system (not shown). Power supply to each band heater 2 is controlled so that the temperature of the heating zone reaches the set temperature. The set temperature of each heating zone is set according to the molding material, and therefore each takes a different value. Due to the low thermal conductivity of the cylinder body 1 made of, for example, an iron alloy material, a thermally discontinuous zone occurs between each heating zone as described above.

In contrast, in this embodiment, a cylindrical heat transfer body 10 made of a highly thermally conductive copper alloy material is interposed between the cylinder body 1 and each band heater 2, and the set temperature of each heating zone is When a temperature difference occurs between adjacent heating zones due to the difference in temperature, the heat is transferred from the band heater 2 on the high-temperature side to the cylinder body 1 in the heating zone on the low-temperature side of the cylinder body 1 via the heat transfer body 10. Therefore, the heat transfer takes place in such a way that the temperature difference between the two heating zones is reduced.As a result, the temperature discontinuity between the heating zones is eliminated and the entire heating cylinder is distributed as shown in FIG. A smooth temperature distribution is formed.

In the above embodiment, the heat transfer body 10 was constructed of a single long cylindrical body, but instead of this, a short cylindrical body disposed between adjacent band heaters to provide a heat transfer path between the two band heaters may be used. A plurality of cylindrical bodies may be used.

Effects of the Invention As described above, according to the present invention, the band heaters are fitted on the outer peripheral surface of the cylinder body between the cylinder body of the heating cylinder and the plurality of band heaters fitted in the cylinder body, and are made of the material that constitutes the cylinder body. A cylindrical heat transfer body made of a highly thermosetting material is interposed, and the set temperature for each heating zone where each band heater is arranged is different, resulting in a temperature difference between adjacent heating zones. Since the heat transfer is performed through the heat transfer body so that the temperature difference between the two heating zones becomes small, the temperature discontinuity between the heating zones, especially between the band heaters, is removed, and the heating A smooth temperature distribution of 1 q can be applied to the entire cylinder, making it possible to stably produce suitable injection molded products.

Moreover, since only a cylindrical heat transfer body is provided, the device configuration is simple, and even if the distance between the band heaters is large, the temperature does not become discontinuous between the band heaters, improving temperature controllability. Therefore, there is no need to provide a large number of band heaters, and the overall configuration of the temperature control system can be simplified and the cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a partial vertical sectional view of a heating cylinder of an injection molding machine according to an embodiment of the present invention, FIG. 2 is a diagram showing the humidity component A5 in the heating cylinder of FIG. A partial longitudinal sectional view showing a conventional heating cylinder, and Fig. 4 are temperature Yri diagrams in the heating cylinder of Fig. 3. 1... Cylinder body, 2... Band heater, 10.
・Heat transfer body. 1st tm 2nd figure stone pL tree 2 da nai 1! ! Figure 3: Sword 0

Claims (1)

[Claims] a cylindrical heat transfer body that is fitted onto the outer circumferential surface of the cylinder body and made of a constituent material having higher thermal conductivity than the constituent material of the cylinder body; A heating cylinder for an injection molding machine, comprising a plurality of band heaters spaced apart from each other in the axial direction of the cylinder body.