Patent Application
20200223116
The present invention relates to a resin temperature detecting device for an injection molding machine configured to detect a temperature of a resin flowing through a resin flow passage in an injection molding machine.
A process for executing injection molding includes an injection process of causing a screw in a cylinder to advance forward and injecting a molten resin accumulated at a front portion of the screw into a mold, a pressure holding process of holding a pressure for a while, a plasticizing process of accumulating the molten resin at a front portion of the cylinder while melting the resin for a next cycle until the resin, with which the mold is filled, is cooled and cured, an injection device retreating process of causing an injection device to retreat such that the molten resin accumulated at a leading end of a nozzle is not cooled and cured due to the mold, and the like.
When the aforementioned processes are repeatedly performed, the resin in the nozzle located between the mold and the cylinder after the molten resin in the cylinder is fed to the mold through the nozzle in an injection operation this time and the mold is filled with the resin is then fed to the mold at the time of next injection. Therefore, it is necessary to manage the resin remaining in the nozzle in a state that is optimal for filling the mold.
Patent Literature 1 describes a tip nozzle for an injection molding machine that includes a temperature sensor such as a thermocouple for managing a temperature of the resin and that is configured to manage the temperature by turning on and off a heater on the basis of the detected temperature.
[Patent Literature 1] Japanese Patent Laid-Open No. 2003-200474
In the tip nozzle disclosed in Patent Literature 1, the thermocouple is provided in a region that is covered with the heater attached to an outer periphery. However, since an interval from the position of the thermocouple to the resin flow passage, through which the resin is injected into the mold, is large, there is a problem that it is not possible to precisely detect the temperature of the resin to be injected into the mold and thus to highly precisely control the temperature of the resin in the resin flow passage.
Thus, an objective of the invention is to provide a resin temperature detecting device for an injection molding machine capable of highly precisely detecting a temperature of a resin to be injected into a mold and highly precisely controlling the temperature of the resin.
As an example of the present disclosure, there is provided a resin temperature detecting device for an injection molding machine, which is provided in the injection molding machine provided with a nozzle part having a resin flow passage to detect a temperature of a resin flowing through the resin flow passage, in which a heat sensing part of a temperature sensor is disposed at a heat sensing position on an injection side of a resin in the nozzle part and in a vicinity of a portion at which an inner diameter of the resin flow passage is smallest.
With this configuration, it is possible to highly precisely detect the temperature of the resin remaining in the resin flow passage and the temperature of the resin immediately before the resin is injected into the mold.
Also, in the example of the disclosure, the resin flow passage of the nozzle part is thick at a base part and is thin on the injection side of the resin. In addition, the heat sensing position is a position that is closer to the injection side than to the base part of the resin flow passage.
With this configuration, it is possible to more precisely detect the temperature of the resin immediately before the resin is injected into the mold.
Also, in the example of the disclosure, the heat sensing position is in a recessed range from an outer surface of a sprue bush, which is a resin inlet part of a mold, to a nozzle touch part.
With this configuration, it is possible to more precisely detect the temperature of the resin immediately before the resin is injected into the mold.
Also, in the example of the disclosure, the heat sensing position is a position at a shortest distance within 1 mm from an inner wall of the resin flow passage.
With this configuration, a response speed of the temperature sensor increases, and it is possible to address a case in which molding is repeated at a short cycle.
Also, in the example of the disclosure, the nozzle part has a hole penetrating therein, and the temperature sensor is inserted into the hole.
With this configuration, it is possible to dispose the temperature sensor at a position that is closer to the leading end of the nozzle.
Also, in the example of the disclosure, the nozzle part has a groove in an outer surface, the temperature sensor is a thermocouple with an outer periphery covered with a sheath, and the sheath of the temperature sensor is disposed along the groove.
With this configuration, the temperature sensor is easily secured to the nozzle part, and the position of the temperature sensor is easily determined with high precision.
According to the invention, it is possible to obtain a resin temperature detecting device for an injection molding machine capable of highly precisely detecting a temperature of a resin to be injected into a mold and highly precisely controlling the temperature of the resin.
Hereinafter, an embodiment for carrying out the invention will be described with reference to several drawings.
First, an example to which the invention is applied will be described with reference to
As illustrated in
With this configuration, it is possible to highly precisely detect the temperature of the resin immediately before the resin is injected into the mold 101.
Next, a configuration of the resin temperature detecting device for an injection molding machine according to the embodiment of the invention will be described with reference to the drawings. As described above,
As illustrated in
The nozzle of the injection molding machine 100 is provided with a sprue bush 110 on which the nozzle of the injection molding machine 100 abuts for guiding the resin into the mold 101. However, a structure between the sprue bush 110 and the mold 101 is illustrated in a simplified manner in
An injection side of a resin in the nozzle part 1 has substantially a conical shape. Also, a projecting end of the nozzle part 1 on the injection side is substantially a spherical surface. A through-hole 13 is formed inside the nozzle part 1 along an outer surface of the conical shape.
The temperature sensor 10 is inserted into the through-hole 13. The temperature sensor 10 is a thermocouple with an outer periphery covered with a sheath in one example. Although a lead wire is drawn out of the temperature sensor 10, illustration thereof is omitted in
At the nozzle part 1, the resin flow passage 11 has an inner diameter that gradually decreases from the base part toward the leading end part N located on the injection side (in the −Z direction among directions illustrated in
The temperature sensor 10 is disposed such that the heat sensing part SP of the temperature sensor 10 is located in the vicinity of the leading end part N, which is a portion at which the inner diameter of the resin flow passage 11 is smallest.
In addition, the position of the heat sensing part SP is a position that is closer to the leading end part N than to a base part (a part with a thick diameter other than the leading end part N) of the resin flow passage 11 in the example illustrated in
Also, the heat sensing part SP of the temperature sensor 10 is located within a range of the leading end part N when seen in a Y-axis direction in this example.
Also, the heat sensing part SP is at a position at a shortest distance (the distance in a direction (Y-axis direction) of an outer surface of the nozzle from an inner wall of the resin flow passage 11 in the state illustrated in
Since the heat sensing part SP of the temperature sensor 10 is located at a position that is close to the resin 12 flowing through the resin flow passage 11 in this manner, it is possible to highly precisely detect the temperature of the resin remaining in the resin flow passage 11 and the temperature of the resin immediately before the resin is injected into the mold.
The temperature control device includes a temperature sensor 10, a temperature adjuster 30, a heater power source 41, a solid state switch 40, and a heater 15. The temperature control device is adapted to control the amount of heat generated by the heater 15 on the basis of a temperature detection signal from the temperature sensor 10 provided at the nozzle part 1.
The temperature adjuster 30 is configured of an A/D converter 31, a PID arithmetic operation part 32, and a D/A converter 33. The A/D converter 31 converts an electromotive force of the temperature sensor 10 (thermocouple) into digital data, and the PID arithmetic operation part 32 obtains an amount of operation on the basis of an externally set target temperature and an output value of the A/D converter 31 and outputs data of the amount of operation to the D/A converter 33. The D/A converter 33 generates a PWM signal in accordance with the amount of operation. The PWM signal is given as an on/off signal for the solid state switch 40.
The temperature of the heater 15 is controlled to follow the target temperature through the operations of the temperature control device illustrated in
In this example, a groove 14 is formed along an outer surface of the portion with the substantially conical shape of the nozzle part 1, and the temperature sensor 10 is attached to the groove 14. Specifically, the sheath of the temperature sensor 10 is bonded to the groove 14. Other configurations are similar to those illustrated in
In this example, the groove 14 is formed along the outer surface of the part with the substantially conical shape of the nozzle part 1, and further, a hole 17 dug in the Y-axis direction from the groove 14 is formed. The temperature sensor 10 is inserted into the hole 17. Other configurations are similar to those illustrated in
If the hole 17 at which the temperature sensor 10 is provided is pierced toward the resin flow passage 11 as illustrated in
The injection side of the resin in the nozzle part 1 has substantially a conical shape. Also, the projecting end of the nozzle part 1 on the injection side is substantially a spherical surface. The hole 17 is formed along an outer surface with the conical shape inside the nozzle part 1. The temperature sensor 10 is inserted into the hole 17. Other configurations are the same as those illustrated in
The sprue bush 110 is attached to a resin injection part of the mold 101. The projecting end of the nozzle part 1 abuts the nozzle touch part NT of the sprue bush 110. The nozzle touch part NT of the sprue bush 110 is recessed from an outer surface S-S of the sprue bush 110.
The heat sensing part SP of the temperature sensor is within a recessed range d from the outer surface S-S of the sprue bush 110 to the nozzle touch part NT.
With this configuration, it is possible to detect the temperature of the resin at a position that is closer to the mold.
Finally, it is a matter of course that the aforementioned embodiment for carrying out the invention is described only for illustrative purposes on all points and is not restrictive. It is possible for those skilled in the art to appropriately add modifications and changes. The scope of the invention is indicated not by the aforementioned embodiment but by the claims. Further, the scope of the invention includes changes from the embodiment within a scope that is equivalent to the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-232248 | Dec 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/042764 | 11/20/2018 | WO | 00 |
