KR100932958B1 - Filling imbalance control device and method used in injection mold - Google Patents

Abstract

The present invention detects the charging imbalance through the temperature and pressure data according to the time inside the cavity obtained from the temperature sensor and the pressure sensor and accordingly the charging imbalance by automatically adjusting the runner cross section through the signal of the control device and the runner cross section adjusting means. It is an object of the present invention to provide an apparatus and method for solving the problem.

In order to achieve the above object, according to the present invention, an injection mold including a plurality of cavities, further comprising a sprue for supplying resin to the plurality of cavities, a plurality of runners, and a plurality of gates. Charge imbalance control device used in the One or more runner section adjusting means for adjusting the size of one or more runner sections of the plurality of runners, a sensor installed to monitor the environment inside the cavity, and the runner section adjusting means based on a monitoring signal transmitted from the sensor It provides a charging imbalance adjusting device comprising a control means for controlling the.

Injection mold, filling imbalance, runner section control means, sensor, control means

Description

Filling imbalance adjusting device and method for injection mold {FILLING IMBALANCE ADJUSTING APPARATUS AND METHOD FOR INJECTION MOLD}

1 is a cross-sectional view showing a state in which the filling imbalance adjusting device of the present invention is mounted on an injection mold.

Figures 2a and 2b is a detailed view of the section adjustment device.

3A is a graph showing a change in temperature value in the cavity when the cross section of the runner is not adjusted.

3B and 3C are graphs showing changes in temperature values in the cavity when the cross section of the runner is adjusted.

4A is a graph showing changes in pressure values in the cavity when the cross section of the runner is not adjusted.

4B and 4C are graphs showing changes in pressure values in the cavity when the cross section of the runner is adjusted.

The present invention relates to a filling imbalance control device for a injection mold including a plurality of cavities and further comprising a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities. will be.

Injection molding is a manufacturing technology that melts a resin, injects it into a cavity formed in an injection mold through sprues, runners, and gates, and solidifies it to form a molded article of a desired shape.

Injection molds used in injection molding are divided into single cavity, multi cavity, and family types according to the product placement and method, and are generally suitable for mass production. Multi-cavity or family molds are used.

The problem of resin filling imbalance which occurs frequently in the molding of many products through injection molding is that it causes defects such as dimensional change, deformation due to residual stress, flash, mold life, and unfilled product. Known.

There are two main causes of filling imbalance: molding side and processing side. First, on the molding side, the actual resin flow inside the mold is caused to vary depending on various factors such as the temperature of the resin, the injection speed, and the temperature of the mold. For this reason, the difference from the theoretical flow balance obtained through injection molding analysis appears. In addition, on the processing side, it is difficult to secure substantially the uniformity of quality because the machining error that occurs during the mold processing is not precisely processed to the theoretically designed dimensions. Therefore, the problem of filling imbalance occurs not only in the mold of the family system having a different shape of the cavity, but also in the mold of the multi-cavity method consisting of the cavity of the same shape.

Until now, in the industrial field, CAE (Computer Aided Engineering) was used to calculate the length and diameter of the runner and gate for uniform charging, and reflected this data in the mold design and fabrication. The trial and error method eliminates charge imbalance by further processing the runner and gate of the mold. However, this method is time-consuming and expensive.

Accordingly, Korean Patent Laid-Open Publication No. 2003-0006321 (published on July 12, 2001) has installed a supply balance control device in the runner to adjust the flow cross-sectional area of the runner in order to eliminate additional processing of the runner and the gate. However, this device is also just to adjust the supply balance through the trial and error method, and the mold must be disassembled to adjust the flow path area of the runner.

The present invention is to solve the problems of the prior art, the charge imbalance is detected through the temperature and pressure data over time inside the cavity obtained from the temperature sensor and the pressure sensor, and thus the cross section of the runner and the signal of the control device and the runner It is an object of the present invention to provide an apparatus and a method for relieving charge imbalance by automatically adjusting through a section adjusting means.

In order to achieve the above object, according to the present invention, an injection including a plurality of cavities, and further includes a sprue, a plurality of runners, and a plurality of gates to supply resin to the plurality of cavities. A filling imbalance adjusting device for a mold, comprising: at least one runner section adjusting means for adjusting the size of at least one of the runners of the plurality of runners, a sensor installed to monitor an environment inside the cavity, and transmitted from the sensor It provides a charging imbalance adjusting device including a control means for controlling the runner cross-section adjusting means based on the monitoring signal.

The charging imbalance adjusting device of the present invention preferably further includes a wired or wireless communication means connected to the sensor for transmitting a monitoring signal between the sensor and the control means.

In addition, the filling imbalance adjusting device of the present invention, the runner cross-section adjusting means, it is preferable to include a protruding member capable of advancing and retreating into the runner, and drive means for driving the advancing and retracting of the protruding member. At this time, the protruding member includes a screw rod screwed to the through hole communicating with the runner, the driving means is coupled to the drive motor and the screw rod and the drive motor, respectively, to drive the drive motor. It is preferable to include a pair of gears meshing with each other to rotate the screw rod.

In addition, the charge imbalance control device of the present invention, the sensor comprises a temperature sensor installed on the cavity wall at the charging end position, or the injection mold further comprises a cavity core, the sensor is the cavity at the charging end position It is preferable to include a temperature sensor installed in the core.

In addition, the charge imbalance control device of the present invention, the sensor comprises a pressure sensor is installed on the cavity wall near the gate, or the injection mold further comprises a cavity core, the sensor is the cavity near the gate It is preferable to include a pressure sensor installed in the core.

On the other hand, according to the present invention, a filling imbalance control method for an injection mold, which includes a plurality of cavities and further includes a sprue, a plurality of runners, and a plurality of gates to supply resin to the plurality of cavities, Monitoring an environment inside the cavity by a sensor, calculating an adjustment amount of at least one runner cross section of the plurality of runners based on a monitoring signal obtained from the sensor, and according to the calculated adjustment amount of the at least one runner cross section It provides a filling imbalance control method of the injection mold comprising the step of adjusting the cross section of the.

In the charging imbalance control method of the present invention, it is preferable that the monitoring signal obtained from the sensor includes a temperature inside the cavity over time, and the buffer time of each of the plurality of cavities is monitored by monitoring the temperature inside the cavity over time. It is desirable to calculate an adjustment amount of at least one runner cross section of the plurality of runners so as to capture and match the cushioning time of each cavity.

In addition, in the charging imbalance control method of the present invention, it is preferable that the monitoring signal obtained from the sensor includes a pressure inside the cavity with time, and also the buffer time of each of the plurality of cavities by monitoring the pressure inside the cavity according to the time. It is preferable to calculate the amount of adjustment of one or more runner cross sections of the plurality of runners so as to capture and to match the buffer time of each cavity.

Embodiments of the present invention will be described below with reference to the drawings.

First, the apparatus of the present invention will be described in detail.

1 shows an injection mold 1 and a filling imbalance control apparatus of the present invention used therein. In FIG. 1, the injection mold 1 is illustrated as a mold having two cavities 2 and 2 ′. However, the filling imbalance adjusting device according to the present invention may be a multi-cavity type or a family type type if a plurality of cavities are provided. It can be used for any injection mold.

The injection mold 1 has a sprue 3, two runners 4 and 4 ′ and two gates 5 and 5 ′ for supplying resin to the cavities 2 and 2 ′. . Therefore, the resin is supplied through the sprue 3 to branch to each runner 4, 4 ′ and then to the cavities 2, 2 ′ via the gates 5, 5 ′.

The filling imbalance adjusting device of the present invention is to monitor the environment inside the cavity (2, 2 ') and the runner section adjusting means installed to adjust the cross-section of any one of the two runner (4, 4'). Sensors 11, 12; 11 ', 12' installed and via sensors 13, 14; 13 ', 14' for transmission of monitoring signals from the sensors 11, 12; 11 ', 12'. Runner section adjusting means based on a wired or wireless communication means (not shown) connected to (11, 12; 11 ', 12') and a monitoring signal transmitted from the sensors 11, 12; 11 ', 12'. It consists of control means (not shown) which controls (10).

Sensors for obtaining information inside the cavities 2, 2 'use pressure sensors 11, 11' or temperature sensors 12, 12 'or both. In the case of the pressure sensors 11 and 11 ', it is preferable to be installed near the gates 5 and 5' so as to obtain a lot of information of the environment inside the cavity 2 and 2 '. In this case, in order to measure the surface temperature of the mold, detect the filling phenomenon of the resin, and to automatically switch the pressure, it is preferable to install at the filling end position of each cavity (2, 2 '). In the case of the temperature sensors 12 and 12 ', since the response speed is faster than the pressure sensors 11 and 11', the utilization is high.

The sensors 11, 12; 11 ', 12' are installed by processing the sensor holes in the walls of the cavities 2, 2 ', which may affect the molding quality of the product's appearance in order to improve the appearance quality of the product. It is more preferable to process and install the sensor holes in the cavity cores 6 and 6 'as shown, rather than the fixed side of the mold (the upper mold part of the cavity in FIG. 1).

2 shows a runner section adjusting means. The runner end section adjusting means includes a protruding member that can move back and forth into the runner 4, and drive means for driving the forward and backward of the protruding member. In this embodiment, the protruding member is a screw rod 10 that is screwed into the through hole 7 communicating with the runner 4, and a driving motor (not shown), a screw rod 10, and a drive are driven to drive the protrusion member. It is provided with a pair of gears (not shown) coupled to the motors and engaged with each other to rotate the screw rod 10 by the driving of the driving motor. Therefore, as the screw rod 10 is rotated by the driving motor, the screw rod 10 can be moved back and forth into the runner 4.

By configuring the runner section adjustment means as described above, the linear movement distance according to the rotation can be easily controlled by using the principle of the screw, so that the change due to the section adjustment can be easily calculated despite the simple structure.

In this embodiment, since the number of runners 4 and 4 'is two, the runner section adjusting means may be provided in only one runner 4, but may be provided in both runners 4 and 4' if necessary. . In addition, in the case of a mold having a large number of runners, the number of runners to be adjusted can be installed.

The signals monitored by the sensors 11, 12; 11 ', 12' are transmitted to the control computer via a wired or wireless communication device connected thereto. The monitored pressure and temperature values are stored in a computer in real time and used to control the runner cross-section.

Next, the filling imbalance adjusting method in the present invention will be described in detail.

First, the environment inside the cavities 2, 2 'is monitored by the sensors 11, 12; 11', 12 '. Monitored pressure and temperature values are stored and analyzed on a computer as described above.

The amount of adjustment of the cross section of the runner 4 is then calculated based on the pressure and temperature values monitored from the sensors 11, 12; 11 ′, 12 ′.

3A is a graph showing changes in temperature values in both cavities 2 and 2 'when the runner cross section is not adjusted. Examining the graph, it can be seen that the temperature value increases rapidly after a certain time. This suddenly changing position is the buffering point and the time at this point is the buffering time t ₂ , t _{2 ′} .

However, since the buffering time t ₂ of the cavity ₂ and the buffering time t _{2 ′} of the cavity _{2 ′} are different from each other, first, overcharge occurs in the buffered cavity 2.

In order to match this cushioning time, the cross section of the runner 4 connected to the cavity 2 where the cushioning takes place first by the above-described device is reduced. Then, according to the reduced cross-section, and slow down the buffer time of the cavity (2), therefore, the buffer time (t ₂ of the cavity (2) the buffer time (t ₂₎ and the cavity _(2), as shown in Figure 3b ) Are approximately equal to each other. However, if the cross section of the runner 4 is excessively reduced, the buffering time t ₂ of the cavity 2 becomes slower than the buffering time t _{2 ′} of the cavity 2 ′ as shown in FIG. 3C. Therefore, proper adjustment of the cross section of the runner 4 is required.

Such adjustment of the cross section of the runner 4 may be made based on the pressure values monitored by the sensors 11, 12; 11 ′, 12 ′.

That is, the cushioning time t ₂ of the cavity 2 is determined by a graph showing the change in the pressure value in both cavities 2 and 2 'when the cross section of the runner 4 shown in FIG. 4A is not adjusted. In contrast to the cushioning time t _{2 ′} of the cavity 2 ′, the cross sections of the runner 4 are adjusted to coincide with each other, so that the cushioning time t ₂ and the cavity ( The buffering time t _{2 'of 2'} ) is approximately equal to each other.

According to the present invention, by detecting the charging imbalance through the temperature and pressure data over time inside the cavity obtained from the temperature sensor and the pressure sensor and accordingly by automatically adjusting the runner cross section through the signal of the control device and the runner cross section adjusting means Charge imbalance can be eliminated.

That is, by adjusting the runner cross section, it is possible to solve the flash phenomenon, the residual stress, the weight deviation, and the like, which are closely related to the effects of overcharging, and also to prolong the mold life.

In particular, unlike the prior art, it is possible to resolve the filling imbalance in real time even without disassembling the mold to process and control.

Claims (16)

delete delete delete delete A filling imbalance adjusting device used for an injection mold including a plurality of cavities and further including a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities, At least one runner section adjusting means for adjusting the size of at least one of the runners of the plurality of runners, a sensor installed to monitor the environment inside the cavity, and the runner section adjusting based on a monitoring signal transmitted from the sensor Control means for controlling the means, And the sensor comprises a temperature sensor mounted to the cavity wall at a charging end position to capture the buffer time of the cavity by detecting a sudden temperature change. A filling imbalance adjusting device used for an injection mold including a plurality of cavities and further including a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities, At least one runner section adjusting means for adjusting the size of at least one of the runners of the plurality of runners, a sensor installed to monitor the environment inside the cavity, and the runner section adjusting based on a monitoring signal transmitted from the sensor Control means for controlling the means, The injection mold further includes a cavity core, and the sensor includes a temperature sensor installed in the cavity core at a charging end position to capture the buffer time of the cavity by detecting a sudden temperature change. Filling imbalance control device used in injection mold. A filling imbalance adjusting device used for an injection mold including a plurality of cavities and further including a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities, At least one runner section adjusting means for adjusting the size of at least one of the runners of the plurality of runners, a sensor installed to monitor the environment inside the cavity, and the runner section adjusting based on a monitoring signal transmitted from the sensor Control means for controlling the means, And said sensor comprises a pressure sensor mounted to said cavity wall near said gate to capture a buffering time of said cavity by sensing a sudden pressure change. A filling imbalance adjusting device used for an injection mold including a plurality of cavities and further including a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities, At least one runner section adjusting means for adjusting the size of at least one of the runners of the plurality of runners, a sensor installed to monitor the environment inside the cavity, and the runner section adjusting based on a monitoring signal transmitted from the sensor Control means for controlling the means, The injection mold further includes a cavity core, and the sensor includes a pressure sensor installed at the cavity core near the gate to capture a buffering time of the cavity by detecting a sudden pressure change. Filling imbalance control device used in injection mold. delete As a filling imbalance control method for an injection mold, comprising a plurality of cavities, and further comprising a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities, Monitoring an environment inside the cavity by a sensor; Calculating an adjustment amount of at least one runner cross section of the plurality of runners based on the monitoring signal obtained from the sensor; And And adjusting the cross section of the runner according to the calculated amount of the at least one runner cross section. The sensor is a temperature sensor provided at the position of the charging end of the cavity in order to capture a rapid temperature change, the capturing time of the cavity, The method of controlling the imbalance filling of the injection mold, characterized in that the monitoring signal obtained from the sensor includes the temperature inside the cavity over time. 11. The method according to claim 10, wherein the temperature of the interior of the cavity is monitored over time to capture the buffering time of each of the plurality of cavities, and to adjust the buffering time of each of the cavities to adjust the runner cross section of at least one of the plurality of runners. Filling imbalance control method of the injection mold, characterized in that for calculating. As a filling imbalance control method for an injection mold, comprising a plurality of cavities, and further comprising a sprue, a plurality of runners, and a plurality of gates for supplying resin to the plurality of cavities, Monitoring an environment inside the cavity by a sensor; Calculating an adjustment amount of at least one runner cross section of the plurality of runners based on the monitoring signal obtained from the sensor; And And adjusting the cross section of the runner according to the calculated amount of the at least one runner cross section. The sensor is a pressure sensor provided near the gate to capture the buffer time of the cavity by detecting a sudden pressure change, The method of controlling the imbalance filling of the injection mold, characterized in that the monitoring signal obtained from the sensor comprises a pressure in the cavity over time. The method according to claim 12, wherein the pressure in the cavity according to the time is monitored to capture the buffer time of each of the plurality of cavities and to adjust the buffer time of each of the cavities to adjust the runner cross section of at least one of the plurality of runners. Filling imbalance control method of the injection mold, characterized in that for calculating. The injection mold according to any one of claims 5 to 8, further comprising a wired or wireless communication means connected to the sensor for transmitting a monitoring signal between the sensor and the control means. Charge imbalance regulator used. The injection mold according to any one of claims 5 to 8, wherein the runner cross-section adjusting means includes a protruding member that can move back and forth into the runner, and drive means for driving the retracting of the protruding member. Charge imbalance adjuster used in. The method of claim 15, wherein the protruding member comprises a screw rod for screwing into the through-hole communicating with the runner, the drive means is coupled to the drive motor, and the screw rod and the drive motor, respectively, the drive motor Filling imbalance control device used in the injection mold, characterized in that it comprises a pair of gears meshing with each other to rotate the screw rod by the driving of.

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