JPH08300432A - Mold apparatus of molding machine - Google Patents

Abstract

PURPOSE: To well control the temp. of a mold for molding a highly heat-resistant resin of which the molding temp. is a specific value or more. CONSTITUTION: In the mold apparatus of a molding machine for molding a highly heat-resistant resin with a molding temp. of 400 deg.C or higher, at least six or more temp. control units consisting of the sheath heaters 7 embedded in a mold and the temp. sensors 8 detecting the temps. of the mold in the vicinity of the sheath heaters 7 are arranged to the respective parts of the mold to be individually controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device of a molding machine such as an injection molding machine, and particularly to a mold device for molding a high heat resistant resin having a molding temperature of 400 ° C. or higher. Technology.

[0002]

2. Description of the Related Art In general general-purpose resins, the molding temperature is 350 ° C. or less, and it is not necessary to maintain the mold temperature at a high temperature. Therefore, the temperature control medium such as oil or water is used for controlling the mold temperature. Is commonly used.

FIG. 6 is a diagram schematically showing a temperature control mechanism of a conventional mold. As shown in FIG. 6, a pipe 52 for circulating a temperature control medium is formed in a mold 51. By forcibly circulating a temperature control medium (temperature control fluid) such as oil or water in the pipe 52, the mold temperature is maintained at a predetermined temperature.

On the other hand, when the molten resin is filled at high speed into the cavity (molding product forming space) of the mold, defects such as the generation of air bubbles due to the entrainment of air and the occurrence of short-circuiting at the end due to air compression occur. To do. Therefore, when the molten resin is filled at a high speed, a decompression device for sucking the air in the cavity may be provided near the mold.

FIG. 7 is a view schematically showing a conventional mold mechanism provided with the above-mentioned pressure reducing device. In the figure, 51 is a mold, 53 is a cavity, 54 is an air suction pipe formed in the mold 51, and 55 is a venturi nozzle 5.
Reference numeral 56 denotes a pressure reducing device including 5a and the like, and reference numeral 56 denotes a connecting pipe connecting the pressure reducing device 55 and the air suction pipe 54.

In the configuration shown in FIG. 7, compressed air is caused to flow through the venturi nozzle 55a at a high speed in the direction of the arrow shown in the figure, whereby the outer peripheral portion of the tip of the venturi nozzle 55a is made negative due to the Venturi tube effect, whereby the inside of the cavity 53 is made. Air is sucked through the air suction conduit 54 and the connection conduit 56, and is discharged from the decompression device 55.

[0007]

As shown in FIG. 6 and as described above, the conventional temperature control mechanism of the mold is such that the temperature control medium such as oil or water is forcibly circulated through the mold so as to make one cycle. The mold temperature is controlled. Therefore, if the temperature of the temperature control medium is properly controlled, the temperature variation of each part of the mold can be kept within a range that does not pose a practical problem.

However, there is a temperature upper limit value in the temperature control using the temperature control medium, and the molding temperature is 400
It is difficult to apply, such as when molding a high heat-resistant resin of ℃ or higher, for example, when adjusting the mold temperature to a high temperature of 150 ℃ or higher, and avoid it from the viewpoint of safety. It should be.

On the other hand, when molding a high heat resistant resin having a molding temperature of 400 ° C. or higher, even if the mold temperature is adjusted to a high temperature of 150 ° C. or higher, the temperature difference between the mold and the molten resin is increased. However, in many cases, high-speed filling is performed so that the temperature of the molten resin does not drop rapidly during injection filling. In this case, as described above, it is necessary to discharge the air in the cavity before the injection filling, but if the decompression device is provided outside the mold as in the conventional configuration shown in FIG. 7,
In addition to lengthening the piping path, the responsiveness deteriorates, and it also becomes an obstacle to downsizing the entire mechanism of the molding machine.

[0010] The present invention has been made in view of the above points,
The purpose is to make it possible to satisfactorily control the temperature of a mold for molding a high heat resistant resin having a molding temperature of 400 ° C. or higher. Another object of the present invention is to make a compact molding machine having a pressure reducing means for sucking / depressurizing the air in the cavity.

[0011]

In order to achieve the above object, the present invention is embedded in a mold in a mold device of a molding machine for molding a high heat resistant resin having a molding temperature of 400 ° C. or higher. At least 6 units or more of temperature control units each including a sheathed heater and a temperature sensor that detects a mold temperature near the sheathed heater are arranged in each part of the mold, and the temperature of each temperature control unit is individually controlled. Composed.

In addition to the above construction, a depressurizing means for sucking the air in the cavity to reduce the pressure is incorporated in the mold.

[0013]

When the temperature of the mold is controlled, it is necessary to minimize the temperature difference between the parts of the mold and make the temperature distribution as uniform as possible. However, for example, when each part is heated by a heater in order to keep the mold temperature at a high temperature of 150 ° C. or higher, if each part is temperature-controlled at the same heater temperature (control for one temperature control) If each heater is driven and controlled simultaneously in the circuit), the mold will be affected by factors such as the difference in the effect of heat from the molten resin filled in the cavity and the difference in the distance from the contact area with the outside air. The temperature of each part of the above varies and the difference in temperature distribution becomes large.

Therefore, as a result of various studies, the inventor of the present application arranged at least 6 units or more of temperature control units each consisting of a sheath heater and a temperature sensor in each part of the mold to make the temperature distribution of each part of the mold uniform. As described above, it has been found that when the temperature control is independently performed for each unit based on the sensor detection result, the difference in the temperature distribution of the mold can be kept within a range that does not pose a practical problem.

The round-bar-shaped sheathed heater used as a heater is, for example, four arranged so as to surround the four sides of the cavity, and an appropriate number of sheathed heaters are arranged before and after the cavity. Are individually driven and controlled based on the temperature detection information from the temperature sensor attached to each. As a result, the temperature difference between the respective parts of the mold becomes as small as possible, and it is possible to guarantee the molding of a good product. That is, in the case of molding a high heat-resistant resin having a molding temperature of 400 ° C. or higher, which is difficult to control with the temperature control medium, the temperature control of the mold can be performed reliably and satisfactorily.

On the other hand, if a decompression device for sucking the air in the cavity to reduce the pressure, for example, a venturi nozzle is installed in the mold, the air pipe path from the cavity to the decompression device is shortened.・ Responsiveness of depressurization is enhanced, which contributes to shortening the molding cycle, and the entire molding machine system can be made compact.

[0017]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a simplified sectional view of a mold device of an injection molding machine according to an embodiment of the present invention. In the figure, 1 is a mold including a fixed mold 2 and a movable mold 3, 4 is a cavity forming a space for forming a molded product, and 5 is a cavity 4.
To the resin injection port 6, 7 is a sheathed heater embedded in each part of the mold 1, and 8 is a thermoelectric generator also embedded in the mold 1 to detect the mold temperature in the vicinity of each sheathed heater 7. It is a pair sensor.

As shown in FIG. 2, the well-known sheathed heater 7 has a heater built in a cylindrical holding casing, and is installed in a round hole formed in the mold 1. Further, the well-known thermocouple sensor 8 shown in FIG.
It is mounted in a round hole drilled in the mold and detects the mold temperature near the corresponding sheath heater 7.

In the present invention, the temperature control unit composed of the pair of the sheathed heater 7 and the thermocouple sensor 8 has 6 units or more, preferably 8 units or more, arranged in each part of the mold, and each unit has In addition, the temperature control is independently performed based on the sensor detection result.

FIG. 4 is a sectional view taken along the line AA of FIG. 1. As shown in FIG. 4, in this embodiment, four temperature control units are arranged so as to surround the four sides of the cavity 4. Thus, the temperature of the region on the 4 side of the cavity 4 can be controlled. Further, as shown in FIG. 1, six temperature control units are arranged above and below the cavity 4 in the figure, and therefore, in this embodiment, a total of ten temperature control units are used to make the mold 1 Is configured to control the temperature of each part of.

In this embodiment having such a configuration,
When molding a high heat-resistant resin with a molding temperature of 400 ° C., for example, each part of the mold 1 is maintained at a high temperature of 150 ° C. so that the temperature distribution of each part of the mold 1 becomes uniform. As a result of independently controlling the temperature of each unit based on the sensor detection result, it was confirmed that the difference in the temperature distribution of the mold 1 is within a range that does not pose a practical problem.

FIG. 5 is a cross-sectional view of an essential part showing a depressurizing mechanism in the cavity in the mold apparatus of this embodiment. In FIG. 5, the temperature control unit is omitted for the sake of simplification of the drawing.

In FIG. 5, 9 is a venturi nozzle 9.
It is a pressure reducing device equipped with a, etc., and is integrally embedded and mounted in the mold 1. Further, 10 is an air suction pipe line formed in the mold 1 for connecting the decompression device 9 and the cavity 4.
Reference numeral 1 is an air outflow conduit formed in the mold 1 for discharging the exhaust gas from the decompression device 9 to the atmosphere.

In the structure shown in FIG. 5, compressed air is caused to flow through the venturi nozzle 9a at a high speed in the direction of the arrow shown in FIG. The air is sucked through the air suction conduit 10 and discharged from the decompression device 9 through the air outflow conduit 11 to the outside air.

By adopting such a configuration, the air piping path (air suction piping 10) from the cavity 4 to the decompression device 9 is shortened, the response of intake and decompression is improved, and the molding cycle is shortened. In addition, the entire molding machine system can be made compact.

[0026]

As described above, according to the present invention, it is possible to reliably and satisfactorily control the temperature of a mold for molding a high heat resistant resin having a molding temperature of 400 ° C. or higher, which contributes to molding of a good product. it can. Further, it is possible to make a compact molding machine having a pressure reducing means for sucking / depressurizing the air in the cavity.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view of a mold device of an injection molding machine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a sheathed heater in FIG.

FIG. 3 is an explanatory diagram showing a thermocouple sensor in FIG. 1.

FIG. 4 is a sectional view taken along line AA of FIG. 1;

FIG. 5 is a cross-sectional view of essential parts showing a depressurizing mechanism in the cavity in the mold device of the injection molding machine according to the embodiment of the present invention.

FIG. 6 is an explanatory view schematically showing a temperature control mechanism of a conventional mold.

FIG. 7 is an explanatory view schematically showing a conventional mold device provided with a pressure reducing means.

[Explanation of symbols]

 1 Mold 2 Fixed Side Mold 3 Movable Side Mold 4 Cavity 5 Sprue 6 Resin Injection Port 7 Sheath Heater 8 Thermocouple Sensor 9 Pressure Reduction Device 10 Air Suction Pipeline 11 Air Outflow Pipeline

Claims (2)

[Claims] 1. A temperature for detecting a mold heater embedded in a mold and a mold temperature in the vicinity of the sheath heater in a mold device of a molding machine for molding a high heat resistant resin having a molding temperature of 400 ° C. or higher. A mold apparatus for a molding machine, wherein at least 6 or more temperature control units each comprising a sensor are provided in each part of the mold, and each temperature control unit is individually temperature-controlled. 2. The mold apparatus of a molding machine according to claim 1, wherein a pressure reducing means for sucking air in the cavity to reduce the pressure is incorporated in the mold.