KR20190022272A - Apparatus and method for positioning sensor for injection molding machine - Google Patents

Abstract

The present application relates to an apparatus and a method for setting a sensor position of an injection molding machine. According to an embodiment of the present invention, a method for setting a sensor position for automatic dwelling conversion of an injection molding machine comprises: a dwelling conversion time measuring step of measuring a time consumed for a molten resin to be filled into a predetermined dwelling conversion position in a mold from an injection start point where an injection molding machine injects the molten resin into the mold, and setting the measured time as a dwelling conversion time; a deceleration time measuring step of measuring a time required to reduce an injection speed when the resin reaches the dwelling conversion position to a predetermined dwelling injection speed, and setting the measured time as a deceleration time; a reference conversion time setting step of setting a time prior to the dwelling conversion time as much as the deceleration time as a reference conversion time; and a sensor position setting step of setting a position where the resin reaches in the mold in the reference conversion time as a sensor position.

Description

Technical Field [0001] The present invention relates to an apparatus and method for positioning a sensor in an injection molding machine,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor positioning device and a setting method of an injection molding machine, and more particularly, to a sensor positioning device and a setting method of an injection molding machine capable of setting the position of a sensor for automatic pressure holding.

An injection molding machine is a device which is heated in a heating cylinder to inject molten resin into a cavity space of a mold apparatus at a high pressure and then cooled and solidified in the cavity space to obtain a molded article. To this end, the injection molding machine is provided with a mold clamping device and an injection molding machine. The mold clamping device includes a fixed mold plate and a movable mold plate. The mold clamping cylinder moves the movable mold plate back and forth to perform mold closing and mold opening . The injection apparatus includes a heating cylinder for heating and melting the resin supplied from the hopper, and an injection nozzle for injecting the molten resin. The injection cylinder is installed in the heating cylinder so that the screw is freely rotatable and forward and backward freely. The resin can be metered by advancing the screw, injecting the resin by the injection nozzle, and retracting the screw.

The present application is intended to provide a sensor position setting device and a setting method of an injection molding machine capable of setting the position of a sensor for automatic post-pressurization switching.

In the method of positioning a sensor for automatic pressure-relief switching of an injection molding machine according to an embodiment of the present invention, the injection position of the resin in the mold is determined based on the position of the pre- Pressure holding time to be measured is measured and set as a holding pressure switching time; A deceleration time measuring step of measuring a time required for decelerating the injection speed at the time when the resin reaches the pressure-saving switching position to a predetermined constant-pressure injection rate, and setting the deceleration time as a deceleration time; A reference switching time setting step of setting a time that is earlier by the deceleration time than the reference pressure switching time as a reference switching time; And a sensor positioning step of setting a position at which the resin reaches within the mold at the reference switching time to a sensor position.

Here, the pressure-relieving switching position may be a position at which the resin reaches the mold when the filling rate of the resin in the mold is a predetermined target filling rate. Here, the target filling rate may be 97-98%.

Wherein the deceleration time measuring step measures the deceleration time using Td = (V-Vp) * A + dt, where Td is the deceleration time (s), V is the injection speed (m / s) A is the deceleration performance of the injection molding machine (s ^ 2 / m), and dt may be the delay time of the injection molding machine. Here, the holding pressure injection speed Vp may be zero.

Here, the reference switching time setting step sets the reference switching time using Rt = Tv-Td, where Rt may be the reference switching time, Tv may be the holding pressure switching time, and Td may be the deceleration time.

Here, the sensor position setting step may set a position where the resin reaches the mold in the reference switching time as a reference area, and set the sensor position in the reference area.

The reference area may be an interface formed between the resin and a cavity in the mold at the reference switching time.

The sensor position setting device according to an embodiment of the present invention is for switching the automatic holding pressure of the injection molding machine and is used when the resin is filled from the injection start point for injecting the molten resin into the mold A measuring unit for measuring a holding time required for decelerating the injection speed at a predetermined holding pressure injection speed when the resin reaches the holding pressure changing position; And an arithmetic unit configured to set a time earlier than the hold-down time by the deceleration time as a reference transition time and set a position where the resin reaches the mold in the reference transition time as a sensor position.

Here, the pressure-relieving switching position may be a position at which the resin reaches the mold when the filling rate of the resin in the mold is a predetermined target filling rate. Here, the target filling rate may be 97-98%.

Here, the measuring unit measures the deceleration time using Td = (V-Vp) * A + dt where Td is the deceleration time (s), V is the injection speed (m / s) (m / s), A is the deceleration performance of the injection molding machine (s ^ 2 / m), dt may be the delay time of the injection molding machine, and the holding pressure injection speed Vp may be zero.

Here, the operation unit sets the reference switching time using Rt = Tv-Td, where Rt may be the reference switching time, Tv may be the holding pressure switching time, and Td may be the deceleration time.

Here, the calculation unit may set a position where the resin reaches the mold at the reference switching time as a reference area, and set the sensor position in the reference area.

The reference area may be an interface formed between the resin and a cavity in the mold at the reference switching time.

Here, the injection molding machine includes: a mold-shaped portion for advancing the movable plate to fasten the mold between the fixed plate and the movable plate when the resin injected into the mold is cooled and solidified to take out the product formed in the mold; An injection part for melting the resin and injecting molten resin into the mold; A controller for controlling operations of the mold-shaped portion and the injection portion so as to sequentially perform mold closing, injection, holding, cooling, mold opening, and taking-out processes; And a sensor unit provided on the sensor position set in the mold and stopping the injection process when the resin is filled up to the sensor position and outputting a voltage-hold switching signal to proceed to the holding process.

In addition, the means for solving the above-mentioned problems are not all enumerating the features of the present invention. The various features of the present invention and the advantages and effects thereof will be more fully understood by reference to the following specific embodiments.

According to the sensor positioning device and the setting method of the injection molding machine according to the embodiment of the present invention, it is possible to set the position of the sensor for switching the automatic pressure holding pressure.

According to the sensor positioning device and the setting method of the injection molding machine according to the embodiment of the present invention, since the automatic pressure switch can be performed at the correct timing, overcharge of the resin in the mold can be prevented.

1 is a schematic view showing an injection molding machine according to an embodiment of the present invention.
2 is a block diagram showing an injection molding machine according to an embodiment of the present invention.
FIGS. 3 and 4 are schematic views showing positions of a pressure-relieving switch and a sensor according to an embodiment of the present invention.
5 is a block diagram illustrating a sensor positioning apparatus according to an embodiment of the present invention.
6 is a flowchart showing a method of setting a sensor position according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art can easily carry out the present invention. In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the drawings, like reference numerals are used throughout the drawings.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to "include" an element means that it may include other elements, rather than excluding other elements, unless specifically stated otherwise.

1 is a schematic view showing an injection molding machine according to an embodiment of the present invention.

Referring to FIG. 1, an injection molding machine 1 according to an embodiment of the present invention may include a molded body 10, an injection portion 20, and a hydraulic circuit 30.

Hereinafter, an injection molding machine 1 according to an embodiment of the present invention will be described with reference to FIG.

The mold clamping portion 10 may include a fixed mold plate 11, a movable mold plate 12, a tie bar 13, a mold clamping cylinder 14, and the like. The fixed plate 11 is a fixed plate and can include an insertion hole 11a. The convex portion of the upper mold 17 can be inserted into the insertion hole 11a and the upper mold 17 can be attached to the fixed plate 11. [ The fixed plate 11 can be mounted on the plurality of tie bars 13 and the fixed plate 11 can be fixed to the right end of the tie bars 13. [

At the left end of the tie bar 13, a mold-clamping cylinder 14 may be provided. The rod of the mold clamping cylinder 14 can be connected to the movable mold plate 12 with the link portion 15 therebetween. The movable plate 12 is a plate to which the lower mold 16 is attached and can be guided by the tie bar 13. [ That is, when the rod of the mold clamping cylinder 14 is extended, the movable plate 12 can be guided by the tie bar 13 and move to the fixed plate 11 side.

The injection section 20 may include an injection cylinder 21, a heating section 22, a hopper 23, a screw 24, a nozzle section 25, an insertion cylinder 26, and the like. The rod of the injection cylinder 21 may be provided with a screw 24 and the frame of the injection cylinder 21 may be integrally formed with the heating part 22 so as to cover the screw 24. The nozzle unit 25 may be formed at the tip of the heating unit 22. [ The rod of the injection cylinder 21 can be connected to the hydraulic motor 46 and can rotate the screw 24 in accordance with the rotation of the hydraulic motor 46. [

The heating section 22 may be provided with a hopper 23 for supplying injection resin. The resin in the hopper 23 can move in the direction of the nozzle unit 25 by the rotation of the screw 24. [ At this time, the resin can be heated and heated in the heating section 22 to be plasticized.

The injection cylinder 21, the heating section 22, the hopper 23, the screw 24 and the nozzle section 25 can be moved laterally by the insertion cylinder 26. That is, when the rod of the insertion cylinder 26 is extended, the nozzle unit 25 can be inserted into the mold 17 of the fixed plate 11. [ Thereafter, when the rod of the injection cylinder 21 is elongated, the nozzle unit 25 can inject resin plasticized therein through the upper mold 17 of the stationary mold plate 11.

The hydraulic actuator such as the mold clamping cylinder 14, the injection cylinder 21, the insertion cylinder 26 and the hydraulic motor 46 can be supplied with the hydraulic oil by the hydraulic circuit 30 and can operate. The hydraulic circuit 30 may be composed of a hydraulic pump 31 and control valves 32, 34, 35, 41, 42, The hydraulic pump 31 can press-feed the hydraulic oil supplied to each of the hydraulic actuators into the hydraulic circuit 30. [ The hydraulic pump 31 may have a capacity capable of operating the hydraulic actuator such as the mold clamping cylinder 14, the injection cylinder 21, the insertion cylinder 26 and the hydraulic motor 46 simultaneously. However, since the hydraulic actuators do not actually operate at the same time, the capacity of the hydraulic motor 46 can be set to be larger than the capacity actually required by the hydraulic injection molding machine 1.

Here, the first control valve 32 can control the pilot pressure of the unloader valve 33 to unload the discharge pressure of the hydraulic pump 31. As a result, the power consumption can be reduced as much as possible, the rise in oil temperature can be prevented, and the life of the pump can be prolonged. That is, the first control valve 32 can convert the hydraulic pump 31 into a load state or a no-load state. The second control valve 34 can be switched to supply the operating oil supplied to the mold clamping cylinder 14 to the cap chamber side pressure chamber 14a or the head side pressure chamber 14b. The third control valve 35 can start or stop the supply of the operating oil to the head side pressure chamber 14b. The fourth control valve 41 can switch the supply direction of the working oil to the insertion cylinder 26 into the cap side pressure chamber 26a or the head side pressure chamber 26b. The fifth control valve 42 can switch the supply direction of the working oil to the injection cylinder 21 to the cap side pressure chamber 21a or the head side pressure chamber 21b. The sixth control valve 44 can start or stop the supply of the hydraulic oil to the hydraulic motor 46. [ The seventh control valve 47 and the relief valves 48, 49 and 50 may be used for back pressure adjustment of the injection cylinder 21 and the insertion cylinder 26.

Next, the operation of the injection molding machine 1 will be described. The injection molding machine 1 can produce a product by sequentially performing a mold closing process, an injection process, a holding process, a metering process, a cooling process, and a mold opening process. Here, the control valve may operate according to the input control signals, and the control signal may be applied to the solenoids 32a, 34a, 34b, 35a, 41a, 41b, 42a, 42b, 44a, 47a, Signal.

First, the first control valve 32 can switch the hydraulic pump 31 to a load state in accordance with an input control signal. Thereafter, in the mold closing process, the solenoids 32a of the first control valve 32, the solenoids 34a of the second control valve 34, and the solenoids 35a of the third control valve 35, Lt; / RTI > In this case, the movable plate 12 advances and the convex portion 16a of the lower mold 16 can be inserted into the concave portion 17a of the upper mold 17. The upper mold 17 and the lower mold 16 can be fixed by applying an electric signal to the solenoid 32a of the first control valve 32 and the solenoid 34a of the second control valve 34 . That is, the mold clamping cylinder 14 can supply a pressure capable of withstanding the pressure received by the lower mold 16 during the injection process. At this time, a gap may be formed between the convex portion 16a of the lower mold 16 and the concave portion 17a of the upper mold 17.

An electric signal is applied to the solenoid 32a of the first control valve 32, the solenoid 34a of the second control valve 34 and the solenoid 41b of the fourth control valve 41 in the injection process, The injection cylinder 21, the heating section 22, the hopper 23, the screw 24 and the nozzle section 25 can be advanced. In this case, the nozzle unit 25 can be inserted into the upper mold 17. [ The solenoid 32a of the first control valve 32, the solenoid 34a of the second control valve 34 and the solenoid 42b of the fifth control valve 42 are electrically connected A signal can be applied. In this case, the rod of the injection cylinder 21 can be advanced, and the plasticized resin stored at the tip end of the heating part 22 can be injected into the injection hole 17b of the nozzle part 25 and the mold 17 Can be injected into the cavity formed between the convex portion 16a of the lower mold 16 and the concave portion 17a of the upper mold 17. [

When the injection process is completed, the holding process can be performed. An electric signal may be applied to the solenoid 32a of the first control valve 32, the solenoid 42b of the fifth control valve 42, and the solenoid 47a of the seventh control valve 47 in the holding process. Thus, the plasticized resin stored in the tip end portion of the heating section 22 can be subjected to a predetermined pressure by the injection cylinder 21. The resin injected into the cavity formed between the convex portion 16a of the lower mold 16 and the concave portion 17a of the upper mold 17 can be gradually contracted by cooling. Therefore, a predetermined pressure can be applied to the plasticized resin located at the tip end of the heating part 22 to replenish the plasticized resin to the shrunk part.

In the weighing step, the screw 24 can be rotated by driving the hydraulic motor 46, and the resin in the hopper 23 can be fed into the heating part 22 as the screw 24 rotates. Further, the resin supplied into the heating section 22 can be heated and melted in the heating section 22.

On the other hand, electric signals are applied to the solenoids 32a of the first control valve 32 and the solenoids 41a of the fourth control valve 41 to control the injection cylinder 21, the heating cylinder 22, the hopper 23, The screw 24 and the nozzle 25 are retracted and the solenoid 32a of the first control valve 32, the solenoid 47b of the seventh control valve 47 and the solenoid 47b of the sixth control valve 44, An electric signal may be applied to the injection cylinder 44a to retreat the rod of the injection cylinder 21. Thereafter, the resin injected into the cavity formed between the convex portion 16a of the mold 16 and the concave portion 17a of the mold 17 may be subjected to a cooling process in which the resin is cooled for a predetermined time.

After the cooling process, a mold opening process can be performed. The mold can be opened by applying an electric signal to the solenoid 32a of the first control valve 32 and the solenoid 34b of the second control valve 34 to retreat the moving template 12 . Further, the formed resin product can be pushed by a cylinder (not shown) protruding from the through hole 16b of the lower mold 16, and can be removed from the lower mold 16. [

Meanwhile, the injection molding machine according to the embodiment of the present invention can be automatically switched to the pressure holding process in the injection process. If the transition from the injection process to the holding process is delayed, the resin in the mold may be overcharged, and if the transfer to the holding process is fast, the resin in the mold may be overcharged. According to the embodiment, the driver of the injection molding machine can directly switch to the pressure holding process, but it can be more stable and efficient to automatically switch to the pressure holding process according to predetermined conditions and the like. For this, an injection molding machine according to an embodiment of the present invention may include a molded body 10, an injection part 20, a sensor part 40, and a control part 50.

Since the mold-shaped portion 10 and the injection portion 20 have been described in detail with reference to FIG. 1, detailed description thereof will be omitted here. Although the configuration of the hydraulic circuit is omitted in Fig. 2, the hydraulic circuit of Fig. 1 may be applied.

The control unit 40 may control the operations of the mold clamping unit 10 and the injection unit 20 to sequentially perform mold closing, injection, holding, cooling, mold opening, and taking out processes. Since the operation of the control unit 40 has been described with reference to FIG. 1, a detailed description thereof will be omitted.

The sensor unit 50 may be installed on a predetermined sensor position in the mold. When the resin is filled up to the sensor position, the sensor unit 50 may detect the filling of the sensor and output a voltage change signal. That is, the sensor unit 50 may stop the injection process and transmit the pressure change-over signal to the control unit 40 so as to switch the pressure holding process.

The sensor position where the sensor unit 50 is located may be a position where the resin reaches the mold at the reference switching time. The reference switching time corresponds to a time earlier than the holding pressure change time by the deceleration time and the holding pressure change time corresponds to a time point at which the holding pressure should be converted into the holding pressure process and the deceleration time may be a time required for switching from the injection process to the holding process . Therefore, the pressure holding process is switched to the holding process by the deceleration time before the holding pressure conversion time to be converted into the actual holding process, so that the holding process can be actually performed from the holding pressure changing time.

Here, the holding pressure change time is a time required for the resin to be filled in the mold from the start of injection to the predetermined holding pressure changing position, and the deceleration time is a time to decelerate the injection speed when the resin reaches the holding pressure changing position to a predetermined holding pressure injection speed It may be the time required for the operation. The deceleration time depends on the deceleration performance of the injection molding machine, and it is possible to calculate the time required from the injection speed of the actual injection molding machine to the holding pressure conversion speed using the deceleration performance of the injection molding machine. In addition to the time required for deceleration, the deceleration time may further include a delay time occurring in the control operation for switching to the actual pressure holding process after transmitting the pressure holding switch signal.

Therefore, by calculating the reference changeover time, it is possible to know the time point at which the actual pressuring process should be switched. In order to detect the reference changeover point, the point where the resin reaches the mold at the reference changeover time can be set as the sensor position. Here, the sensor may be a temperature sensor or the like, and when a high-temperature resin contacts the sensor, the sensor may detect the high temperature resin to generate a voltage-holding signal.

5 is a block diagram illustrating a sensor positioning apparatus according to an embodiment of the present invention.

Referring to FIG. 5, the sensor positioning apparatus according to an embodiment of the present invention may include a measuring unit 110 and a calculating unit 120.

Hereinafter, a sensor positioning apparatus according to an embodiment of the present invention will be described with reference to FIG.

The measuring unit 110 can measure the holding pressure change time required when filling the molten resin from the injection starting point to inject the molten resin into the mold of the injection molding machine up to the preset holding pressure switching position. In order to automatically proceed to the holding process after the injection molding process, the injection molding machine may set the holding pressure switching position in advance in the mold. Therefore, when the resin injected by the injection step is filled up to the post-pressurization switching position, the injection process can be stopped and the process can be switched to the post-pressurization process. Here, as shown in Fig. 3, the pressure-holding position A may be set in advance, and when the sensor is provided on the pressure-holding position A, the resin is filled up to the pressure-holding position A The time can be confirmed. Accordingly, the measuring unit 110 can measure the post-hold time, which is the time required for the resin to be filled up to the post-pressure change position after injection of the resin into the mold starts.

3, depending on the embodiment, when the filling rate of the resin in the mold corresponds to 97 to 98%, the holding pressure switching position is set to the holding pressure changing position .

The injection molding machine does not drive the injection cylinder 21 any longer and the resins stored in the tip end portion of the heating part 22 are introduced into the mold part by the pressure applied in the holding process . Therefore, as shown in Fig. 3, the conversion from the injection step to the pressure holding step can be performed at the time when the filling of the inside of the mold is almost completed.

On the other hand, when the resin is filled in the mold by the injection process, the resin can be sequentially introduced from the injection port in the mold. Here, the molds are the same and the injection speed is kept constant for each injection step, so that the position of the resin corresponding to each filling rate can be kept constant.

Thereafter, the measuring unit 110 can measure a deceleration time required for deceleration of the injection speed at a predetermined holding pressure injection speed when the resin reaches the holding pressure changing position. In the injection step, the resin can be injected into the mold at a constant injection speed, but depending on the embodiment, the injection speed may vary. Therefore, the measuring unit 110 can measure the time required for the injection speed to decelerate to the holding pressure injection speed on the basis of the injection speed when the resin reaches the pressure-holding position.

Specifically, the measuring unit 110 can measure the deceleration time using Td = (V-Vp) * A + dt. Here, Td is the deceleration time (s), V is the injection speed (m / s), Vp is the boom injection speed (m / s), A is the deceleration performance of the injection molding machine (s ^ 2 / Lt; / RTI > That is, the deceleration time can be measured by adding the delay time of the injection molding machine to the time required to decelerate the injection speed to the positive pressure injection speed. Here, dt is the delay time of the injection molding machine, and may be the time required until the control signal is switched to the actual pressure holding process after inputting the control signal for switching to the pressure holding process. On the other hand, the holding pressure at the holding pressure is an injection speed at which the resin is injected into the mold in the holding process, and may be generally zero.

Here, the measuring unit 110 may include a sensor or the like in the actual injection molding machine to measure the post-pressurization switching time and the deceleration time. However, according to the embodiment, it is also possible to generate the model through the analysis of the injection molding machine, and to measure the respective hold pressure switching time and the deceleration time in a manner of simulating the processes of the injection molding machine using the model.

The calculation unit 120 can set a time earlier than the hold-down time by the deceleration time as the reference transition time and set the position where the resin reaches the mold at the reference transition time as the sensor position. Specifically, the reference switching time can be set using Rt = Tv-Td, where Rt may be the reference switching time, Tv may be the holding pressure switching time, and Td may be the deceleration time. That is, when the pressure is switched to the pressure holding process after reaching the pressure holding time, the transition to the pressure holding process may be delayed, and the resin in the mold may be overcharged. Therefore, it is possible to switch to the pressure holding process in advance before the hold pressure switching time, which is the point at which the actual pressure holding process should be converted, thereby overcoming the problem of overcharging. As measured by the measuring unit 110, the deceleration time Td may be required for switching from the injection process to the holding process. Therefore, in consideration of the deceleration time Td, the reference switching time point can be set so as to switch to the pressure holding process earlier than the post-pressure change time by the deceleration time.

Then, the calculation unit 120 can confirm the position where the resin filled in the mold reaches when the reference switching time is reached through experiments or simulations, and can set the sensor position using the position. Here, the position at which the resin reaches the mold in the reference switching time can be set as the reference area, and in some embodiments, the boundary formed between the resin and the cavity in the mold at the reference switching time can be set as the reference area have. At this time, the sensor position can be set to be included in the reference area. That is, as shown in FIG. 4, the reference area s can be set and the sensor position B can be set on the reference area s so that the sensors are installed in the sensor position B. Here, the calculation unit 120 may arbitrarily set the sensor position B on the reference area s using a random function or the like. In some embodiments, the calculation unit 120 performs machine learning on a plurality of sensor positions, And a point indicating the result can be set to the sensor position B. [ It is also possible to set the optimum sensor position B by performing fluid analysis and the like on the movement of the resin in the mold.

On the other hand, the sensor may be provided at the sensor position (B), and the sensor senses the temperature of the high temperature resin to confirm that the resin has reached the sensor position. Accordingly, the sensor senses the resin and can transmit the control signal to the control unit of the injection molding machine or the like, and the control unit can control the injection molding machine to proceed to the pressure holding process in the injection process.

6 is a flowchart showing a method of setting a sensor position according to an embodiment of the present invention.

Referring to FIG. 6, the sensor position setting method according to an embodiment of the present invention may include a step of measuring a pressure change time (S10), a deceleration time measuring step (S20), a reference switching time setting step (S30) (S40).

Hereinafter, a method of setting a sensor position according to an embodiment of the present invention will be described with reference to FIG.

In the post-pressurization switching time measuring step S10, the time during which the resin is filled from the start of injection for injecting the molten resin into the mold to the predetermined post-pressurization switching position in the mold can be measured and set as the post-pressurization switching time. In order to automatically proceed to the holding process after the injection process, the holding pressure switching position in the mold can be set in advance. Thereafter, when the resin injected by the injection process is filled up to the transferring position, the injection process can be stopped and the process can be switched to the transferring process. Therefore, in the step of measuring the pressure-pressure conversion time (S10), it is possible to measure the pressure-pressure conversion time, which is the time required until filling of the pressure-pressure conversion position after the injection of resin starts.

Here, the holding pressure switching position can be set using the filling rate at which the resin is filled in the mold. For example, when the filling rate of the resin in the mold corresponds to 97 to 98%, the position where the resin in the mold reaches can be set as the holding pressure switching position. That is, as shown in Fig. 3, when the resin in the mold is mostly filled, the process can be switched to the holding process. When the resin is filled in the mold by the injection process, the resin can be sequentially introduced from the injection port in the mold. Here, if the molds are the same and the injection speed is kept constant for each injection step, the position of the resin corresponding to each filling rate can be kept constant.

However, when the resin is injected to the transferring position to the transferring pressure, that is, when the transferring time of the transferring pressure reaches the transferring time, it is necessary to stop the injection process and proceed to the transferring step. However, in the case of high-speed injection or the like, it may not be immediately switched to the holding-pressure process at the holding pressure switching time depending on the deceleration performance of the injection molding machine or the like. In this case, the transition to the pressure holding step may be delayed, and the resin in the mold may be overcharged.

In the deceleration time measuring step S20, the time required for decelerating the injection speed to a predetermined constant-pressure injection speed may be measured and set as the deceleration time. In the injection step, the resin can be injected into the mold at a constant injection speed. Depending on the embodiment, the injection speed can be varied according to the progress of the injection step. Therefore, in the deceleration time measuring step S20, it is possible to measure the time required for deceleration at the holding pressure injection speed on the basis of the injection speed when the resin reaches the post-transfer pressure changing position.

Specifically, in the deceleration time measuring step S20, deceleration time can be measured using Td = (V-Vp) * A + dt. Here, Td is the deceleration time (s), V is the injection speed (m / s), Vp is the boom injection speed (m / s), A is the deceleration performance of the injection molding machine (s ^ 2 / Lt; / RTI > That is, the deceleration time can be measured by adding the delay time of the injection molding machine to the time required to decelerate the injection speed to the positive pressure injection speed. Here, dt is the delay time of the injection molding machine, and may be the time required until the control signal is switched to the actual pressure holding process after inputting the control signal for switching to the pressure holding process. On the other hand, the holding pressure at the holding pressure is an injection speed at which the resin is injected into the mold in the holding pressure process. Normally, the holding pressure at the holding pressure can be zero since injection is not performed in the holding process.

In the reference switching time setting step (S30), the reference switching time can be set to a time that is earlier by the deceleration time than the holding pressure switching time. Specifically, the reference switching time can be set using Rt = Tv-Td, where Rt may be the reference switching time, Tv may be the holding pressure switching time, and Td may be the deceleration time.

That is, when the pressure is switched to the pressure holding process after reaching the pressure holding time, the transition to the pressure holding process may be delayed, and the resin in the mold may be overcharged. Therefore, it is possible to switch to the pressure holding process in advance before the hold pressure switching time, which is the point at which the actual pressure holding process should be switched to, thereby solving the problem of overcharging or the like. As measured in the deceleration time measuring step S20, the deceleration time Td may be required to switch from the injection process to the holding process. Therefore, in consideration of the deceleration time Td, the reference switching time point can be set so as to switch to the pressure holding process earlier than the post-pressure change time by the deceleration time.

In the sensor position setting step (S40), the position at which the resin reaches the mold in the reference switching time can be set as the sensor position. Through experiments or simulations, it is possible to identify the position where the resin filled in the mold reaches when the reference switching time is reached, and the sensor position can be set using this. Here, the position at which the resin reaches the mold in the reference switching time can be set as the reference area, and in some embodiments, the boundary formed between the resin and the cavity in the mold at the reference switching time can be set as the reference area have. The sensor position can be set in the reference area. That is, as shown in FIG. 4, the reference area s can be set and the sensor position B can be set on the reference area s so that the sensors are installed on the sensor position B. Here, the sensor position B can be arbitrarily set by using a random function or the like on the reference area s. According to the embodiment, by performing a machine learning or the like for a plurality of positions, Position (B). It is also possible to set the optimum sensor position B by performing fluid analysis and the like on the movement of the resin in the mold.

On the other hand, the sensor may be provided at the sensor position (B), and the sensor senses the temperature of the high temperature resin to confirm that the resin has reached the sensor position. Accordingly, the sensor senses the resin and can transmit the control signal to the control unit of the injection molding machine or the like, and the control unit can control the injection molding machine to proceed to the pressure holding process in the injection process.

The present invention is not limited to the above-described embodiments and the accompanying drawings. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: shaped portion 20:
30: Hydraulic circuit 40: Sensor unit
50: Injection section S10: Step of measuring the hold-pressure conversion time
S20: deceleration time measuring step S30: reference switching time setting step
S40: Sensor position setting step

Claims (17)

A method of positioning a sensor for automatic deflection of an injection molding machine,
Measuring the time during which the resin is filled from the injection starting point at which the molten resin is injected into the mold until the resin is filled up to the predetermined set pressure change position in the mold, and setting the fixed pressure change time as the set pressure change time;
A deceleration time measuring step of measuring a time required for decelerating the injection speed at the time when the resin reaches the pressure-saving switching position to a predetermined constant-pressure injection rate, and setting the deceleration time as a deceleration time;
A reference switching time setting step of setting a time that is earlier by the deceleration time than the reference pressure switching time as a reference switching time; And
And setting a position at which the resin reaches within the mold at the reference switching time to a sensor position.
2. The apparatus according to claim 1,
Wherein the resin is a position at which the resin reaches the mold when the filling rate filled in the mold is a predetermined target filling rate.
3. The method of claim 2,
Wherein the target filling rate is 97-98%.
The method according to claim 1, wherein the deceleration time measuring step
The deceleration time is measured using Td = (V-Vp) * A + dt,
T is the deceleration time (s), V is the injection speed (m / s), Vp is the compression injection speed (m / s), A is the deceleration performance of the injection molding machine (s ^ 2 / Wherein the time is a time.
5. The method of claim 4,
And the holding pressure injection speed Vp is zero.
The method as claimed in claim 1, wherein the reference switching time setting step
Rt = Tv-Td, wherein Rt is the reference switching time, Tv is the holding pressure switching time, and Td is the deceleration time.
The method of claim 1, wherein the sensor positioning step
Wherein a position at which the resin reaches the mold at the reference switching time is set as a reference area and the sensor position is set in the reference area.
8. The method of claim 7,
And a boundary surface formed between the resin and a cavity in the mold at the reference switching time.
A sensor position setting apparatus for switching an automatic holding pressure of an injection molding machine,
A transferring time required for filling the molten resin into the mold from the injection starting point to the predetermined transferring position of the resin to the preset transferring position, A measuring unit for measuring a deceleration time required to decelerate at a speed; And
And a calculating unit that sets a time earlier than the holding time by the deceleration time as a reference switching time and sets a position at which the resin reaches the mold in the reference switching time as a sensor position.
10. The apparatus according to claim 9,
Wherein the resin is a position at which the resin reaches the mold when the filling rate filled in the mold reaches a preset target filling rate.
11. The method of claim 10,
Wherein the target filling rate is 97-98%.
The apparatus as claimed in claim 9, wherein the measuring unit
The deceleration time is measured using Td = (V-Vp) * A + dt,
T is the deceleration time (s), V is the injection speed (m / s), Vp is the compression injection speed (m / s), A is the deceleration performance of the injection molding machine (s ^ 2 / Time of the sensor.
13. The method of claim 12,
And said holding pressure injection speed Vp is zero.
10. The image processing apparatus according to claim 9,
Rt = Tv-Td, wherein Rt is the reference switching time, Tv is the holding pressure switching time, and Td is the deceleration time.
10. The image processing apparatus according to claim 9,
Sets a position where the resin reaches the mold at the reference switching time as a reference area, and sets the sensor position in the reference area.
16. The method of claim 15,
Wherein the reference position is an interface formed between the resin and a cavity in the mold at the reference switching time.
The injection molding machine according to claim 9, wherein the injection molding machine
A mold for moving the movable plate forward to clamp the mold between the stationary plate and the movable plate when the resin injected into the mold is cooled and solidified to take out the product formed in the mold;
An injection part for melting the resin and injecting molten resin into the mold;
A controller for controlling operations of the mold-shaped portion and the injection portion so as to sequentially perform mold closing, injection, holding, cooling, mold opening, and taking-out processes; And
And a sensor unit disposed on the sensor position set in the mold and outputting a voltage-hold switching signal for stopping the injection process and proceeding to a holding process when the resin is filled up to the sensor position. Setting device.

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