JP2004237700A - Injection molding machine and its temperature monitoring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine which does not cause poor molding such as a burnt or discolored resin by determining whether the heat generated in or given to the cylinder device including the heating cylinder, the injection nozzle, the water-cooling cylinder comes from the heater or from self-heating caused by shearing. <P>SOLUTION: The injection molding machine has a cylinder device 10 in which a supplied resin material is heated and melt with a heater 15 and from which the molten resin is injected and a temperature sensing part 70 which is installed on the cylinder device 10 and senses the temperatures of the cylinder device 10. The temperature sensing part 70 has first temperature sensors 71a-75a which sense the temperatures of the bore region of the cylinder device 10 and second temperature sensors 71b-75b which sense the temperatures of the outside surface region at the same positions in the axial directions of the first temperature sensors 71a-75a and the cylinder device 10. The machine also has a display part which displays the results measured by the first temperature sensors 71a-75a and the second temperature sensors 71b-75b. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an injection molding machine having a cylinder device for heating a resin material and a method for monitoring the temperature thereof.
[0002]
[Prior art]
This type of injection molding machine is disclosed, for example, in JP-A-7-290531.
[0003]
The injection molding machine includes a mold clamping device that opens and closes a mold and performs mold clamping, and a cylinder that is disposed opposite to the mold clamping device and heats and melts a supplied resin material with a heater to inject the molten resin into the mold. And a cylinder device having a shape. The cylinder device is equipped with a heating cylinder in which the screw is rotatably arranged inside, a water-cooled cylinder in which the hopper is connected behind the heating cylinder, and a screw cooling unit. And an injection nozzle for injecting the molten resin by advancing the screw during the injection process after being stored.
[0004]
FIGS. 1A and 1B show an example of the structure of an apparatus similar to the injection molding machine disclosed in this publication. Referring to FIGS. 1A and 1B, the injection molding machine includes a cylinder device 10 having a heater 15, a temperature detection unit 20 mounted on the cylinder device 10, and detecting a temperature of the cylinder device 10. have. The cylinder device 10 includes a cylindrical heating cylinder 11, an injection nozzle 12 formed at one axial end of the heating cylinder 11, and a water-cooled cylinder 13 mounted at the other axial end of the heating cylinder 11. I have. A screw 14 is provided in the cylinder device 10 so as to be rotatable. Further, the temperature detection unit 20 provided in the cylinder device 10 includes a temperature sensor 21 for detecting the temperature of the water-cooled cylinder 13, temperature sensors 22 a to 24 a and 22 b to 24 b for detecting the temperature of the heating cylinder 11, and an injection nozzle 12. And a temperature sensor 25 for detecting the temperature of each section of the section until the supplied resin material is heated and melted and injected.
[0005]
[Patent Document 1]
JP-A-7-290531
[Problems to be solved by the invention]
In the conventional method for measuring the temperature of a cylinder device in an injection molding machine, including the examples shown in FIGS. 1A and 1B, the temperature measurement points of a heating cylinder, an injection nozzle, and a water-cooled cylinder are near the inner wall. It takes time to transfer heat from the heater to the temperature measurement point. Therefore, even if the temperature detection value of the temperature measurement point installed near the inner surface of the cylinder device reaches the set temperature value and immediately turns off the heater, the cylinder device still has residual heat given before turning off the heater. Therefore, extra heat is added to the resin in the heating cylinder. For these reasons, the amount of heat applied to the resin is not constant, and the molten state of the resin to be measured is not stable, or excessive supply or insufficient heat of the molded product causes problems such as burnt or discoloration of the molded product.
[0007]
Therefore, the technical problem of the present invention is to detect whether the heat given to the cylinder device, the injection nozzle, and the water-cooled cylinder is generated by a heater or by self-heating generated by shearing, and molding such as burning or discoloration of resin. An object of the present invention is to provide an injection molding machine capable of preventing product defects.
[0008]
[Means for Solving the Problems]
According to the present invention, a cylinder device having a cylindrical shape for injecting a molten resin by heating and melting a supplied resin material with a heater, and a temperature detector mounted on the cylinder device and detecting a temperature of the cylinder device In the injection molding machine having a part, the temperature detecting part is provided with a plurality of temperature sensors for detecting temperatures of at least an inner diameter region and an outer diameter region at the same position in the axial direction of the cylinder device. Is obtained.
[0009]
According to the present invention, the plurality of temperature sensors are a first temperature sensor for detecting a temperature in an inner diameter region of the cylinder device, and an outer diameter at the same axial position of the first temperature sensor and the cylinder device. A second temperature sensor for detecting the temperature of the area, and wherein at least one set of a combination of the first and second temperature sensors is provided in a heater zone controlled by the same control signal. Machine.
[0010]
According to the present invention, further, the injection molding machine having the combination of the first and second temperature sensors at each of the plurality of positions in the axial direction of the cylinder device is obtained.
[0011]
Further, according to the present invention, the injection molding machine further has a display unit for displaying at least one of the detection values of the first and second temperature sensors.
[0012]
Further, according to the present invention, a temperature difference between the first and second temperature sensors is calculated from the detection results of the first and second temperature sensors, and the temperature difference is set to a predetermined allowable value. If it is larger than the above, it is determined that the temperature of the cylinder device is caused by self-heating of the resin material that is sheared rather than the heating by the heater, and a monitoring unit that issues an alarm to that effect is further provided. The above-described injection molding machine is obtained.
[0013]
Further, according to the present invention, a cylinder device having a cylindrical shape for injecting a molten resin by heating and melting a supplied resin material with a heater, and mounted on the cylinder device to detect a temperature of the cylinder device In the temperature monitoring method for an injection molding machine having a temperature detection unit, a plurality of temperature sensors provided in the temperature detection unit detect temperatures of at least an inner diameter region and an outer diameter region at the same axial position of the cylinder device. And a method for monitoring the temperature of the injection molding machine.
[0014]
Further, according to the present invention, the temperature detecting unit detects a temperature of an inner diameter region of the cylinder device, a first temperature sensor, and detects a temperature of the first temperature sensor and an outer diameter region of the cylinder device. And a temperature monitoring method for the injection molding machine, further comprising a step of displaying at least one of the detection values of the first and second temperature sensors.
[0015]
Further, according to the present invention, a temperature difference between the first and second temperature sensors is calculated from the detection results of the first and second temperature sensors, and the temperature difference is set to a preset allowable value. If the temperature is greater than the temperature of the cylinder device, it is determined that the temperature of the cylinder device is caused by self-heating of the resin material which is sheared more than the heating by the heater, and a step of issuing an alarm to that effect is provided. A method for monitoring the temperature of the injection molding machine is obtained.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an injection molding machine and a temperature monitoring method according to an embodiment of the present invention will be described with reference to the drawings.
[0017]
[Embodiment 1]
Referring to FIGS. 2A and 2B, this injection molding machine includes a cylinder device 10 having a heater 15 and a cylinder device as in the conventional example shown in FIGS. 1A and 1B. And a temperature detector 70 that is mounted on the cylinder 10 and detects the temperature of the cylinder device 10. The cylinder device 10 includes a cylindrical heating cylinder 11, an injection nozzle 12 formed at one axial end of the heating cylinder 11, and a water-cooled cylinder 13 mounted at the other axial end of the heating cylinder 11. I have. A screw 14 is provided in the cylinder device 10 so as to be rotatable.
[0018]
The temperature detecting unit 70 detects a first temperature sensor group 70a that detects a temperature in an inner diameter region of the cylinder device 10, and an outer diameter region of the cylinder device 10 at the same position as the first temperature sensor group 70a in the axial direction of the cylinder device 10. And a second temperature sensor group 70b for detecting the temperature of
[0019]
The first temperature sensor group 70a mainly detects the heat of fusion generated when the resin material supplied from a hopper (not shown) attached to the water cooling cylinder 13 is melted by the rotation of the screw 14 in the heating cylinder 11. On the other hand, the second temperature sensor group 70b mainly detects heat generated from the heater 15 for heating the heating cylinder 11.
[0020]
More specifically, as the first temperature sensor group 70a, a temperature sensor 71a for detecting the temperature of the water-cooled cylinder 13, temperature sensors 72a to 74a for detecting the temperature of the heating cylinder 11, and a temperature of the injection nozzle 12 A temperature sensor 75a is provided near the inner wall of the cylinder device. On the other hand, as a second temperature sensor group 70b, a temperature sensor 71b for detecting the temperature of the water-cooled cylinder 13, temperature sensors 72b to 74b for detecting the temperature of the heating cylinder 11, and a temperature sensor 75b for detecting the temperature of the injection nozzle 12 Are provided near the outer wall of the cylinder device.
[0021]
Here, instead of the water-cooled cylinder as the resin supply unit, an air-cooled cylinder having a heat sink, a fan, or the like on the outer wall may be provided. In this case, while the temperature of the biting portion of the resin material supplied from the hopper is detected by the first temperature sensor, the temperature near the outer wall radiated from the heat sink or the fan of the air-cooled cylinder by the second temperature sensor. Can be detected. By reducing the temperature deviation between the two, the stability of the resin biting can be monitored, and the measuring time can be stabilized. As a result, it is possible to stabilize the thermal history imparted to the resin over the entire plasticizing region, stabilize the measuring process, and prevent problems with the molded product.
[0022]
Referring also to FIG. 3, the injection molding machine further includes a display unit 30 for displaying detection results of the first and second temperature sensor groups 70a and 70b.
[0023]
The display unit 30 includes amplifiers 31a and 31b connected to the temperature sensors 71a to 75a and the temperature sensors 71b to 75b, a controller 32 to which detection results of the amplified temperature sensors are input, and a controller 32. The display 33 is configured by a connected liquid crystal display or the like.
[0024]
With the above configuration, the user of the injection molding machine refers to the display on the display 33 and determines whether any of the temperature differences between the temperature sensors 71a to 75b and the temperature sensors 71b to 75b is set to a predetermined allowable value. If it is larger than the value, it is determined that the temperature of the cylinder device 10 (the heating cylinder 11, the heating nozzle 12, the water-cooling cylinder 13) is caused by self-heating of the resin material that is sheared more than the heating by the heater. , An alarm is displayed on the display 33. As a result, it is possible to prevent a molded article defect such as burnt or discoloration of the resin which may occur conventionally.
[0025]
Further, by displaying the temperature detection values of the inner diameter region and the outer diameter region at the same position in the axial direction on the display 33, the molten resin in the cylinder device for controlling the heater and the heat of the heater attached to the cylinder device are controlled. By grasping the transfer characteristics, it is possible to realize optimal heater temperature control according to the molding conditions.
[0026]
[Embodiment 2]
The injection molding machine according to the second embodiment of the present invention has the configuration shown in FIGS. 2A and 2B as in the first embodiment. Therefore, description of portions having the same configuration as in the first embodiment will be omitted.
[0027]
Referring to FIG. 4, the present injection molding machine obtains the respective temperatures of first temperature sensors 71a to 75a and second temperature sensors 71b to 75b from the detection results of first and second temperature sensor groups 70a and 70b. The difference is calculated, and when the temperature difference between the first temperature sensors 71a to 75a and the second temperature sensors 71b to 75b is larger than a preset allowable value, the temperature of the cylinder device 10 is higher than that of the heater. An alarm unit 40 is further provided as monitoring means for judging that the heat is caused by self-heating of the sheared resin material and issuing an alarm to that effect.
[0028]
The alarm unit 40 includes amplifiers 41a and 41b connected to the temperature sensors 71a to 75a and the temperature sensors 71b to 75b, respectively, and a temperature difference “a−” between the amplified temperature sensors 71a to 75a and the temperature sensors 71b to 75b. b), a comparator 43 for comparing the temperature difference “ab” with an allowable value set in advance and stored in a memory in the controller 44, and a comparison result by the comparator 43 is “ When the allowable value is smaller than (ab), the controller 44 determines that the temperature of the cylinder device 10 is caused by self-heating of the resin material that is sheared rather than heated by the heater, and outputs an alarm signal to that effect. And a display 45, a flash lamp 46, and a buzzer 47 that display, emit light, and emit a buzzer or siren according to an alarm signal from the controller 44. It is configured Ri.
[0029]
With the above-described configuration, the user of the injection molding machine refers to the display 45, the flash lamp 46, and the buzzer 47, and determines whether any of the temperature differences between the temperature sensors 71a to 75a and the temperature sensors 71b to 75b respectively. When an alarm is issued when the temperature is larger than the allowable value set in advance, the molding conditions are adjusted, and the temperature of the cylinder device 10 (the heating cylinder 11, the heating nozzle 12, the water-cooling cylinder 13) is higher than the heating by the heater. The situation that is caused by self-heating of the resin material to be sheared is avoided. As a result, it is possible to prevent a molded article defect such as burnt or discoloration of the resin which may occur conventionally.
[0030]
A combination of the first temperature sensor and the second temperature sensor is provided at each of a plurality of positions in the axial direction of the cylinder device 10, and the allowable value is set at each of a plurality of positions in the axial direction of the cylinder device 10. Therefore, the alarm unit 40 issues an alarm when the temperature difference of at least one of the plurality of axial positions of the cylinder device 10 is larger than a preset allowable value. .
[0031]
Further, in the present invention, the first temperature sensor and the second temperature sensor do not necessarily have to be located at the same position in the axial direction, and may be arranged shifted in the axial direction. In this case, the temperature difference at the same position in the axial direction can be obtained by calculating the detected temperature detected value.
[0032]
【The invention's effect】
The injection molding machine according to the present invention detects whether the temperature rise of the water-cooled cylinder, the heating cylinder, the injection nozzle, etc. of the cylinder device is due to the heating of the heater or to the self-heating caused by shearing. It is possible to suppress a molded article defect such as discoloration, or to stabilize the biting of the resin material in the resin supply section, thereby suppressing the occurrence of a molded article defect.
[Brief description of the drawings]
1 (a) and 1 (b) are schematic cross-sectional views showing a conventional injection molding machine.
FIGS. 2A and 2B are schematic sectional views showing an injection molding machine according to an embodiment of the present invention.
FIG. 3 is a schematic circuit diagram showing an injection molding machine according to Embodiment 1 of the present invention.
FIG. 4 is a schematic circuit diagram showing an injection molding machine according to Embodiment 2 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Cylinder device 11 Heating cylinder 12 Injection nozzle 13 Water cooling cylinder 14 Screw 15 Heater 20 Temperature detection part 21, 22a, 22b, 23a, 23b, 24a, 24b, 25 Temperature sensor 31a, 31b Amplifier 32 Controller 33 Indicator 40 Alarm part 41a, 41b Amplifier 42 Difference calculator 43 Comparator 44 Controller 45 Indicator 46 Flash lamp 47 Buzzer 70 Temperature detector 70a First temperature sensor group 70b Second temperature sensor group 71a-75a, 71b-75b Temperature sensor

Claims (8)

Injection molding having a cylinder device having a cylindrical shape for injecting a molten resin by heating and melting a supplied resin material with a heater, and a temperature detector mounted on the cylinder device and detecting a temperature of the cylinder device. On the machine,
An injection molding machine, characterized in that the temperature detecting section is provided with a plurality of temperature sensors for detecting temperatures in at least an inner diameter region and an outer diameter region at the same position in the axial direction of the cylinder device. The plurality of temperature sensors are a first temperature sensor that detects a temperature in an inner diameter region of the cylinder device, and a second temperature sensor that detects a temperature in an outer diameter region at the same axial position of the first temperature sensor and the cylinder device. And two temperature sensors,
The injection molding machine according to claim 1, wherein one or more sets of the combination of the first and second temperature sensors are provided in a heater zone controlled by the same control signal. The injection molding machine according to claim 2, wherein a combination of the first and second temperature sensors is provided for each of the plurality of positions in the axial direction of the cylinder device. 4. The injection molding machine according to claim 2, further comprising a display unit that displays at least one of the detected values of the first and second temperature sensors. 5. A temperature difference between the first and second temperature sensors is calculated from the detection results of the first and second temperature sensors, and when the temperature difference is larger than a predetermined allowable value, 5. A monitoring device for judging that the temperature of the cylinder device is caused by self-heating of the resin material which is sheared more than the heating by the heater, and further issues a warning to that effect. The injection molding machine according to any one of the above. Injection molding having a cylinder device having a cylindrical shape for injecting a molten resin by heating and melting a supplied resin material with a heater, and a temperature detector mounted on the cylinder device and detecting a temperature of the cylinder device. In the method of monitoring the temperature of the machine,
Temperature monitoring of an injection molding machine, comprising a step of detecting at least the temperature of an inner diameter region and an outer diameter region at the same position in the axial direction of the cylinder device by a plurality of temperature sensors provided in the temperature detection unit. Method. The temperature detection unit includes a first temperature sensor that detects a temperature of an inner diameter region of the cylinder device, a first temperature sensor, and a second temperature sensor that detects a temperature of an outer diameter region of the cylinder device. Equipped,
7. The temperature monitoring method for an injection molding machine according to claim 6, further comprising a step of displaying at least one of the detection values of said first and second temperature sensors. A temperature difference between the first and second temperature sensors is calculated from the detection results of the first and second temperature sensors, and when the temperature difference is larger than a predetermined allowable value, 8. The method according to claim 6, further comprising a step of determining that the temperature of the cylinder device is caused by self-heating of the resin material which is sheared more than the heating by the heater, and issuing an alarm to that effect. Temperature monitoring method for injection molding machines.

Images