JP4549733B2 - Mold temperature adjusting device and adjusting method - Google Patents

Description

  The present invention relates to a mold temperature adjusting device and a temperature adjusting method in which a switching timing of a high temperature medium and a low temperature medium is appropriately adjusted to shorten a molding cycle time.

In the injection process of the injection molding machine, when the temperature of the mold is low, the surface of the molten resin injected into the cavity of the mold is rapidly solidified. In this case, since the transfer of the cavity surface of the mold to the molded product becomes insufficient, defects called sink, weld, and silver may occur on the surface of the molded product.
Therefore, solidification of the surface of the molten resin is delayed by filling the mold with a molten resin previously heated to a temperature equal to or higher than the thermal deformation temperature of the resin. Then, a molding method of performing mold opening has been proposed.

  When such a molding method is employed, it is desirable to shorten the molding process cycle. Therefore, recently, a system for controlling the molding timing based on the temperature of the molded product and a system for rapidly raising and lowering the temperature of the mold have been introduced.

Conventional mold heating / cooling switching devices for molding machines include a high-temperature heat medium heater, a high-temperature heat medium recovery tank, a low-temperature heat medium cooler, a low-temperature heat medium recovery tank, a high-temperature heat medium and a low-temperature heat medium. It has the structure provided with the some pump etc. which each distribute | circulate a medium.
In this mold heating / cooling switching device, the mold is heated by passing a high-temperature heat medium through a temperature control path (heat medium path) provided in the mold, and the mold reaches a temperature suitable for resin filling. At that time, the supply of the high-temperature heat medium is stopped. When molten resin is filled in the mold cavity, the heat medium passed through the mold is switched to a low temperature heat medium, thereby cooling the mold. When the mold reaches a temperature suitable for mold opening, supply of the low-temperature heat medium is stopped, mold opening and taking out of the molded product are performed, and then mold closing and mold reheating are performed. .

In the above mold heating / cooling switching device, when the mold temperature is switched from a high temperature to a low temperature, the low temperature heat to which the high temperature heat medium remaining in the temperature control path of the mold is newly supplied to the temperature control path. It is pushed out by the medium and collected in a high-temperature heat medium recovery tank.
Further, when the temperature of the mold is switched from the low temperature to the high temperature, the high temperature heat medium whose temperature has been adjusted in the high temperature heat medium recovery tank is supplied to the temperature adjustment passage, whereby the low temperature heat remaining in the temperature adjustment passage is obtained. The medium is pushed outward and collected in a low-temperature heat medium recovery tank. (For example, see Patent Document 1)

JP 10-34657 A

  By the way, since the mold has a large heat capacity, the time constant of heat change is large. According to the heating / cooling switching device described in Patent Document 1 described above, since it takes a long time for the mold to reach the set temperature, there is a problem that the molding cycle becomes long.

In order to eliminate such problems, the temperature of the high temperature heat medium should be set higher and the temperature of the low temperature heat medium should be set lower to shorten the time until the mold temperature reaches the set temperature. . However, by doing so, the temperature of the mold cannot be quickly set to the target temperature because of so-called excessive temperature control.
In addition, mold temperature adjustment must be performed in consideration of the weight of the mold, the temperature of the heat medium, the flow velocity, the resin material, etc., but in the past it was adjusted depending on trial and error and the experience and intuition of the operator. For this reason, it was difficult to perform optimum adjustment.

  The present invention has been proposed in order to solve such problems, and it is possible to appropriately adjust the switching timing of the high-temperature heat medium and the low-temperature heat medium to shorten the molding cycle time. An object is to provide an adjusting device and a mold temperature adjusting method.

The present invention is a mold temperature control device that performs temperature control of a mold by selectively flowing a high-temperature heat medium and a low-temperature heat medium at a predetermined temperature through a heat medium passage provided in the mold, A mold temperature measuring means for actually measuring the mold temperature, and a value TH obtained by subtracting a heating overshoot temperature correction value ΔTH from a predetermined resin filling start mold temperature value TH when the mold is heated. When the temperature rises to -ΔTH, the supply of the high-temperature heat medium to the mold is stopped, and when the mold is cooled, the temperature of the mold is set to a predetermined cooling completion mold temperature TL, and a cooling undershoot temperature correction value Mold temperature control means for stopping the supply of the low-temperature heat medium to the mold when the value drops to a value obtained by adding ΔTL1 to TL + ΔTL1.
The heating overshoot temperature correction value ΔTH is a predicted rise temperature value that defines the supply stop time of the high-temperature heat medium so that overshoot of the mold temperature is suppressed, and the cooling undershoot temperature correction value ΔTL1 Is a predicted lowering temperature value that defines the supply stop point of the low-temperature heat medium so that undershooting of the mold temperature is suppressed.

The mold temperature control means is configured to measure the temperature rise corresponding to the heating overshoot temperature correction value ΔTH by actually measuring the temperature of the mold with the mold temperature measurement means, or a high temperature warming time set value. Recognizing the time S1 by the time measuring means and measuring the temperature decrease corresponding to the cooling undershoot temperature correction value ΔTL1 by actually measuring the temperature of the mold with the mold temperature measuring means, or recognized by the temperature of the mold is measured by the time measuring unit of time S2 of descending from the value TL + ΔTL1 to the value TL.

  The mold temperature control means starts supplying the high-temperature heat medium to the mold when the temperature of the mold falls to the value TL + ΔTL2 (<ΔTL1), and the temperature of the mold rises to the value TH. It is configured to start supplying the low-temperature heat medium to the mold at a time.

The mold temperature control means measures the value TL + ΔTL2 by the mold temperature measurement means when the temperature of the mold falls to the value TL + ΔTL2 (<ΔTL1), or the low temperature heat retention time set value SH Can be recognized by measuring time with a time measuring means.

The temperature of the high-temperature heat medium, the temperature of the low-temperature heat medium, the resin filling start mold temperature TH, the heating overshoot temperature correction value ΔTH, the cooling completion mold temperature TL, the cooling undershoot temperature correction value ΔTL1, and The mold temperature control condition setting means for setting the high temperature heat medium supply start mold temperature correction value ΔTL2 as the mold temperature control condition, the mold temperature control condition in the molding process is displayed, and the mold temperature control condition in the actual molding process is displayed. Display means for displaying the actual temperature change of the mold;
Can be further provided.

  The display means can switch and display the mold temperature control condition and the measured temperature change on the same screen.

  The heating overshoot temperature correction value ΔTH is predicted based on the time constant of the temperature change of the mold when the mold is heated, and the cooling undershoot temperature correction value ΔTL1 is calculated as the mold itself. A means for predicting based on the time constant of the temperature change of the mold when the mold is cooled can be further provided.

The present invention also provides a mold temperature adjustment method for controlling the temperature of a mold by selectively flowing a high temperature heat medium and a low temperature heat medium at a predetermined temperature through a heat medium passage provided in the mold. The mold temperature adjusting method includes a step of actually measuring the temperature of the mold, and when the mold is heated, the temperature of the mold is changed from a predetermined resin filling start mold temperature value TH to a heating overshoot temperature correction value ΔTH. The supply of the high-temperature heat medium to the mold at the time when the temperature rises to TH-ΔTH, and when the mold is cooled, the temperature of the mold is a predetermined cooling completion mold temperature TL And the step of stopping the supply of the low-temperature heat medium to the mold when the temperature drops to the value TL + ΔTL1 obtained by adding the cooling undershoot temperature correction value ΔTL1.
The heating overshoot temperature correction value ΔTH is a predicted rise temperature value that defines the supply stop time of the high-temperature heat medium so that overshoot of the mold temperature is suppressed, and the cooling undershoot temperature correction value ΔTL1 Is a predicted lowering temperature value that defines the supply stop point of the low-temperature heat medium so that undershooting of the mold temperature is suppressed .

The temperature rise corresponding to the heating overshoot temperature correction value ΔTH is measured by measuring the temperature of the mold by the mold temperature measuring means or by measuring the high temperature heat retention time set value S1 by the time measuring means. Can be recognized. Further, the temperature drop corresponding to the cooling undershoot temperature correction value ΔTL1 is measured by actually measuring the temperature of the mold by the mold temperature measuring means, or the temperature of the mold is changed from the value TL + ΔTL1 to the value TL. It can be recognized by measuring the time S2 descending by the time measuring means.

The time S1 can be predicted based on the time constant of the temperature change of the mold when the mold is heated, and the time S2 is the time when the mold is cooled. It can be predicted based on the time constant of the temperature change of the mold.
The supply of the high-temperature heat medium is started, for example, when the temperature of the mold falls to a value TL + ΔTL2 (<ΔTL1), and the supply of the low-temperature heat medium is performed, for example, when the temperature of the mold is a value TH. It starts when it rises.
When the temperature of the mold falls to the value TL + ΔTL2 (<ΔTL1), the value TL + ΔTL2 is actually measured by the mold temperature measuring means, or the low temperature heat retention time set value SH is timed by the time measuring means. Can be recognized.

The mold temperature adjustment method according to the present invention includes the temperature of the high temperature heat medium, the temperature of the low temperature heat medium, the resin filling start mold temperature TH, the heating overshoot temperature correction value ΔTH, and the cooling completion mold temperature TL. The step of setting the cooling undershoot temperature correction value ΔTL1 and the high temperature heat medium supply start mold temperature correction value ΔTL2 as mold temperature control conditions, respectively, and the mold temperature control on the reference mold temperature curve in the molding process And a step of displaying on the display means a first image in which conditions are added, and displaying on the display means a second image showing the actual temperature change of the mold in the actual molding process. Can do.

The heating overshoot temperature correction value ΔTH can be predicted based on a time constant of the mold temperature change when the mold is heated, and the cooling undershoot temperature correction value ΔTL1 is It can be predicted based on the time constant of the mold temperature change when the mold alone is cooled.

According to the present invention, when the mold is heated, when the temperature of the mold rises to a value TH−ΔTH obtained by subtracting the heating overshoot temperature correction value ΔTH from the predetermined resin filling start mold temperature value TH. The supply of the high-temperature heat medium to the mold is stopped, and when the mold is cooled, the temperature of the mold decreases to a value TL + ΔTL1 obtained by adding a cooling undershoot temperature correction value ΔTL1 to a predetermined cooling completion mold temperature TL. At that time, the supply of the low-temperature heat medium to the mold is stopped. Therefore, the molding cycle time can be shortened without causing overshoot or undershoot of the mold temperature.

  In the present invention, the heating overshoot temperature correction value ΔTH is predicted based on the time constant of the actual temperature change of the mold when the mold is heated, and the cooling undershoot temperature correction value ΔTL1 is Since the prediction is based on the time constant of the actual temperature change of the mold when the mold is cooled, the heating overshoot temperature correction value ΔTH and the cooling undershoot temperature correction value ΔTL1 can be optimally set.

  Furthermore, according to the present invention, the temperature control condition setting means for setting the mold temperature control condition is provided in the injection molding condition setting / display means provided in the molding machine control means for controlling the injection molding machine. Since the mold temperature control condition set by the condition setting means and the actual measurement value of the mold in the actual molding process are displayed on the injection molding condition setting / display means, the mold control device There is no need to separately provide control condition setting means and display means. Therefore, the device cost can be reduced.

A first embodiment of a mold temperature adjusting device and a mold temperature adjusting method according to the present invention will be described below with reference to the drawings. In this embodiment, water is used as a heat medium for heating and cooling the mold, but a heat medium other than water such as oil or water vapor may be used.
FIG. 1 is a schematic diagram showing a main part of an injection molding machine and a mold temperature adjusting device according to the first embodiment, FIG. 2 is a block diagram showing a temperature adjustment control system of the mold temperature adjusting device, and FIG. FIG. 4 is a view showing an example of an image showing a mold temperature setting value entry frame and an actual measurement value for each operation process of the molding machine. FIG. 4 shows an actual measurement waveform of the temperature change of the mold when the mold is heated and cooled. An example of an image is shown.

First, the configuration of the mold clamping device 20 and the mold temperature adjusting device 30 of the injection molding machine will be described with reference to FIG.
The mold clamping device 20 includes a fixed die plate 2 fixedly supported by the base 1 and a movable die plate 3 facing the fixed die plate 2. The movable die plate 3 is movably supported by a guide rail 13 laid on the base 1 via a linear bearing 18 so as to be close to and away from the fixed die plate 2.
For example, a hydraulically driven hydraulic cylinder 12 is used to move the movable die plate 3. A fixed mold 4 and a movable mold 5 are respectively attached to the opposing surfaces of the fixed die plate 2 and the movable die plate 3. Accordingly, the dies 4 and 5 are opened and closed by the movement of the movable die plate 3 by the hydraulic cylinder 12.

The fixed die plate 2 incorporates a plurality of mold clamping hydraulic cylinders 2a. The hydraulic cylinder 2a is built in, for example, the four corners of the fixed die plate 2.
A tie bar 9 having a thread groove at one end is directly connected to the ram 8 slidably disposed in each hydraulic cylinder 2a. One end of each tie bar 9 passes through the movable die plate 3 and is screwed into a half nut 11 installed on the side opposite to the mold of the movable die plate 3. Therefore, each tie bar 9 can move integrally with the movable die plate 3.

  The hydraulic switching valve 16 switches the driving hydraulic pressure of the mold opening / closing cylinder 12, the mold clamping cylinder 2a, the injection screw 7, and the like, and is controlled by a command given from the molding machine control device 15. The molding machine control device 15 includes setting display means 15a including a touch key type image display panel. In this setting display means 15a, molding conditions of the molding machine such as injection pressure are set, and measured values such as injection pressure are displayed in the form of waveforms or the like.

  The injection unit 10 is for injecting molten resin into a mold cavity formed by mold-clamping a fixed mold 4 and a movable mold 5, and is composed of an injection cylinder 6, an injection screw 7, and the like. The injection cylinder 6 includes a nozzle that contacts the resin inlet of the fixed mold 4 during the injection operation. The injection screw 7 is driven forward and backward by a drive mechanism (not shown) for injection of molten resin, and is rotated by a drive mechanism (not shown) for plasticizing the resin.

  When the molded product in the cavity is cooled and solidified, the movable mold 5 is disconnected from the fixed mold 4. Thereafter, the movable mold 5 is separated from the fixed mold 4 by the operation of the moving hydraulic cylinder 12, and the molded product is taken out. A mold temperature sensor 62 is attached to the movable mold 5. The mold temperature sensor 62 may be provided in the fixed mold 4 or may be provided in both the fixed mold 4 and the movable mold 5.

Next, the mold temperature adjusting device 30 will be described.
The low-temperature water tank 23 incorporates a low-temperature water temperature regulator (not shown) that adjusts the low-temperature water to a low set temperature. A pipe 31a attached to the bottom of the low-temperature water tank 23 is connected to the heat medium inlets of the dies 4 and 5 via the low-temperature water pump 26, the low-temperature water pipe 31c, the on-off valve 52 and the supply pipe 31d. On the other hand, the pipe 31 e attached to the upper part of the low-temperature water tank 23 is connected to the heat medium outlet of the molds 4, 5 via the on-off valve 55 and the return pipe 35.

  A low-temperature water temperature sensor 63 provided in the low-temperature water tank 23 detects the temperature of the low-temperature water in the tank 23 that is a heat medium. The output of the low-temperature water temperature sensor 63 is a control for maintaining the temperature of the water in the tank 23 at the low target temperature, specifically, the refrigerant passing through the low-temperature water temperature regulator provided in the tank 23. Used to control the amount of.

  The high temperature water tank 24 has a built-in high temperature water temperature regulator (not shown) that adjusts the high temperature water to a high set temperature. A pipe 41 provided in the lower part of the high-temperature water tank 24 is provided with a high-temperature water pump 28 for circulating high-temperature water, and is connected to the supply pipe 31 d via an on-off valve 53. On the other hand, a pipe 42 provided on the upper portion of the high-temperature water tank 24 is connected to the return pipe 35 via an on-off valve 54.

  The high temperature water tank 24 is provided with a high temperature water temperature sensor 64 that detects the temperature of the high temperature water in the tank 24. The output of the high-temperature water temperature sensor 64 is a control for maintaining the temperature of the high-temperature water in the tank 24 at the above-mentioned high set temperature, specifically, heat passing through a high-temperature water temperature regulator provided in the tank 24. Used to control the amount of medium.

  When the high-temperature water pump 28 is operated with the on-off valves 52 and 55 closed and the on-off valves 53 and 54 opened, the high-temperature water from the high-temperature water tank 24 flows through the heat medium passages of the molds 4 and 5. The molds 4 and 5 are heated. At this time, if the operation of the low-temperature water pump 26 is continued, the water sent from the low-temperature water tank 23 to the connection pipe 31b returns to the tank 23 through the flow path and the pipe 37 throttled by the water pressure regulating valve 61. The water pressure in the pipe 31b will rise to a predetermined value. The pipe 31 b communicates with the bottom of the recovery tank 25 via the pipe 36, and the upper part of the recovery tank 25 communicates with the high-temperature water tank 24 via the pipe 44. Accordingly, the water pressure in the pipe 31b is transmitted to the high temperature water tank 24 through the recovery tank 25. As a result, the saturated vapor pressure of the high temperature water in the tank 24 is increased, and the temperature of the high temperature water is set to 100 degrees. Adjustment and holding can be performed as described above.

  When the on-off valves 53 and 54 are closed and the operation of the high-temperature water pump 28 is stopped, the reflux of the high-temperature water is stopped. Therefore, by opening the on-off valves 52 and 55, the low temperature water from the low temperature water tank 23 can be returned to the molds 4 and 5 to cool the molds 4 and 5.

  The vertical cylindrical heat recovery tank 25 connected to the high temperature water tank 24 via the pipe 44 includes the heat medium passage volume of the molds 4 and 5, the internal volume of the high temperature water supply pipe 41, and the supply pipe 31d. Of the return pipe 35, the pipe volume of the section 35a from the heat medium outlet of the dies 4 and 5 to the connecting portion of the high temperature water return pipe 42, and the volume of the high temperature water return pipe 42 in total. Is also formed so as to increase its volume. Therefore, the heat recovery tank 25 functions to suppress mixing of high temperature water and low temperature water.

  The mold temperature adjusting device 30 having the above-described configuration is controlled by a mold temperature control device 32 that cooperates with the molding machine control device 15. In FIG. 2, components that are mechanically built in or adjacent to each other are collectively shown, pipes (heat medium pipes and hydraulic pipes) are indicated by double lines, and electric signal lines are indicated by single lines. .

In FIG. 2, the mold temperature control device 32 includes a control processing unit (CPU), a storage circuit for storing set values, actual measurement values, display image data, and the like, and an input / output circuit. The image display means 33 is provided in the vicinity of the operator's hand together with the setting means 46.
The image display means 33 includes a touch key type image display panel as shown in FIG. In the display image of the image display panel, the setting position of the mold temperature in the molding process, the operation start position of the timer, and the like can be designated with touch keys. The set values of temperature and time are input with a numeric key provided on the setting means 46.

The mold temperature control device 32 sets the temperature of the water in the low-temperature water tank 23 detected by the low-temperature water temperature sensor 63 to the low-temperature water set value (of the low-temperature water tank) set by the setting means 46 (TLW in FIG. 3). The temperature adjustment of the low-temperature water provided in the low-temperature water tank 23 is performed so that the temperature deviation is eliminated, that is, the temperature of the water in the low- temperature water tank 23 is maintained at the low-temperature water set value. Adjust the flow rate of the refrigerant flowing through the heat exchanger. Note that the flow rate of the refrigerant is adjusted by controlling an electromagnetic valve (not shown).

Similarly, the mold temperature control device 32 sets the temperature of the water in the high temperature water tank 24 detected by the high temperature water temperature sensor 64 to the high temperature water set value (of the high temperature water tank) set by the setting means 46 (FIG. 3 ) . The temperature of the water in the high-temperature water tank 24 is maintained at the high-temperature water set value so that the temperature deviation is eliminated. Adjust the flow rate of the heat medium flowing through the high-temperature water temperature controller (heat exchanger).
In addition, by raising the saturation temperature of the water vapor in the tank 24 by the water pressure adjusting action by the water pressure adjusting valve 61 described above, it is possible to stably maintain the high temperature water at a high target temperature of 100 degrees or more.

  The molding machine control device 15 switches the hydraulic switching valve 16 in accordance with a molding process program, sends hydraulic oil to each hydraulic cylinder responsible for each process of the injection molding machine, and rotates the injection screw 7 to plasticize the resin. Drive the motor to drive.

  The mold temperature control device 32 detects the actual temperatures of the molds 4 and 5 detected by the mold temperature sensor 62 and the set temperatures of the molds 4 and 5 corresponding to the respective molding steps (targets set by the setting means 46). When the actual temperature of the molds 4 and 5 matches a set temperature corresponding to a certain molding process, the molding machine controller 15 is instructed to move to the next molding process, and the mold The mold temperature adjusting device 30 is instructed to set a timer for determining the change of the heat medium sent to the molds 4 and 5 or the change timing of heating and cooling.

  Hereafter, with reference to FIGS. 1-4, the effect | action of the molding process of an injection molding machine and the metal mold | die temperature control apparatus 30 linked with this is demonstrated.

Heating and mold 4, 5 prior to the filling of the molten resin, in order to cool the mold 4, 5 after filling of the resin in advance, the hot water set point (hot water tank) THW, low temperature water setpoint (low hot water tank) TLW, mold heating time of the heating overshoot temperature correction value .DELTA.TH, cooling during mold cooling undershoot temperature correction value DerutaTL1, resin filling start mold temperature TH, cooling End Ryokin type After the temperature TL and the supply of the low temperature water are stopped, the mold temperature correction value ΔTL2 when starting the supply of the high temperature water is set by the setting means 46.

  Incidentally, an object having a large heat capacity such as the molds 4 and 5 has a low heat transfer rate. For this reason, even if the feeding of the heat medium is stopped when the temperature of the molds 4 and 5 reaches the set temperature, a phenomenon that the temperature further changes occurs. That is, during heating, a phenomenon (overshoot) occurs in which the temperature of the molds 4 and 5 exceeds the set temperature after stopping the feeding of the heat medium, and during cooling, the temperature of the molds 4 and 5 is set to the set temperature after stopping the feeding of the heating medium. (Undershoot) occurs. The overshoot temperature and the undershoot temperature mean the rising temperature and falling temperature of the molds 4 and 5 after stopping the feeding of the heat medium, respectively.

When setting the above-mentioned high-temperature water set value (for a high-temperature water tank) THW, low- temperature water set value (for a low- temperature water tank ) TLW, etc., the rectangles displayed as THW, TLW, etc. After touching the frame, a specific numerical value is input with the numeric keypad provided in the setting means 46 in the frame.

The heating overshoot temperature correction value ΔTH is a predicted rise temperature value that defines the supply stop time of the high-temperature heat medium so that the overshoot of the temperature of the molds 4 and 5 is suppressed, and the cooling undershoot The temperature correction value ΔTL1 is a predicted falling temperature value that defines the supply stop time of the low-temperature heat medium so that undershoot of the mold temperature is suppressed.
The heating overshoot temperature correction value ΔTH and the cooling undershoot temperature correction value ΔTL1 can be predicted using the following method.

That is, the molds 4 and 5 are heated and cooled in a state where the resin is not filled (dry cycle), and the time constant of the temperature change of the molds 4 and 5 is measured. This time constant corresponds to the heat capacity of the molds 4 and 5, and the heating overshoot and the cooling undershoot become more noticeable as the time constant increases. Therefore, the overshoot temperature correction value (ΔTH) and the undershoot temperature correction value (ΔTL1) are predicted and set based on this time constant.

The image display means 33 can display the measured waveform of the mold temperature change when the mold is heated and cooled (dry cycle) as an image on the screen of the image display panel.
When a sample mold is used and the temperature of the mold is raised and lowered by dry cycle using high-temperature water at 145 ° C. and low-temperature water at 22 ° C., the measurement result of the temperature is shown in FIG. An image is displayed as shown in FIG.
When the mold temperature at the start of injection is 120 ° C and the temperature change with respect to the surrounding time is seen, a temperature rise of 15 ° C is observed in 5 seconds, and when the cooling end temperature is around 70 ° C, the temperature drops by 20 ° C in about 10 seconds. Is seen. Therefore, the mold temperature control device 32 calculates the time constant based on the change in the mold temperature and the up / down time, and the heating overshoot temperature correction value (ΔTH) and the cooling undershoot temperature are calculated from the time constant. A correction value (ΔTL1) is predicted.

Operation during mold heating:
The mold temperature control device 32 is configured so that the measured values TTKH and TTKL from the low temperature water temperature sensor 63 and the high temperature water temperature sensor 64 are the high temperature water temperature (set value) THW and the low temperature water while all the on-off valves 52 to 55 are closed. It is determined whether or not the temperature (set value) TLW has been reached, and when the measured values TTKH and TTKL are confirmed to have reached the set temperature, the on-off valves 53 and 54 are opened, and the high-temperature water pump 28 Start driving. Thereby, high temperature water is supplied to the molds 4 and 5.
Thereafter, when the CPU of the mold temperature control device 32 determines that the mold temperature has reached TH-ΔTH (see FIG. 3), the on-off valves 53 and 54 are closed and high-temperature water based on the command from the CPU. The pump 28 is stopped, and as a result, the supply of hot water to the mold is stopped.

Operation during resin filling and mold cooling:
The injection unit 10 stands by in a state where the molten resin is stored at the tip of the injection cylinder 6. When the mold temperature rises from the value TH-ΔTH by the heating overshoot temperature correction value ΔTH and reaches the value TH, that is, the resin filling start mold temperature value TH, the mold temperature control device 32 moves to the molding machine control device 15. A screw operation command signal is sent. Thereby, the injection screw 7 is moved forward, and a filling process for filling the resin into the mold cavity is started.

By the way, it can be known based on the output of the mold temperature sensor 62 that the temperature of the molds 4 and 5 has increased to the value TH. However, the high temperature heat retention time set value S1 can be predicted from the time constant measured in the dry cycle. Accordingly, the time point at which the mold temperature reaches the value TH may be recognized by measuring the time S1 from the time point when the mold temperature has reached the value TH-ΔTH. In this case, the time S1 can be measured by the timer.

At the same time as the filling of the resin into the mold cavity is started, the on-off valve 52 and the on-off valve 54 are opened by the mold temperature control device 32. Thereby, since the low temperature water is supplied to the molds 4 and 5, the high temperature water stored in the heat medium passage in the molds 4 and 5 is discharged and replaced with the low temperature water. After the replacement with the low-temperature water is completed (after the cooling water replacement time set value SR has elapsed), the mold temperature control device 32 opens the open / close valve 55 and the open / close valve 54 provided in the high-temperature water pipe 42. Close. As a result, low-temperature water is circulated and supplied to the mold, so that the mold cooling process proceeds.
The time SR can be predicted from a time constant measured in the dry cycle. Therefore, the time point when the replacement of the heat medium passages in the molds 4 and 5 with the low-temperature water is completed can be recognized by measuring the time SR with the timer.

Switching the heating medium to the mold and opening the mold:
When the mold temperature reaches the value TL + ΔTL1, the mold temperature control device 32 closes the on-off valves 52 and 55 to stop the supply of the low-temperature water to the mold, and the mold temperature reaches the value TL + ΔTL2. After (or after the low temperature heat retention time set value SH shown in FIG. 3 has elapsed since the supply of the low temperature heat medium is stopped), the on-off valve 53 is opened. Thereby, since the high temperature water is supplied to the molds 4 and 5, the low temperature water stored in the heat medium passage in the mold is discharged and replaced with the high temperature water.

By the way, it can be known based on the output of the mold temperature sensor 62 that the temperatures of the molds 4 and 5 have reached the value TL + ΔTL2. However, the low temperature heat retention time set value SH can be predicted from the time constant measured in the dry cycle. Therefore, the time when the mold temperature reaches the value TL + ΔTL2 may be recognized by measuring the time SH from the time when the mold temperature reaches the value ΔTL1. In this case, the time SH can be measured by the timer.

When the mold temperature falls to the value TL, that is, the cooling completed mold temperature value TL, a mold opening command signal is sent from the mold temperature control device 32 to the molding machine control device 15, and as a result, the molds 4 and 5 are opened. The molded product is taken out. Thereafter, the molds 4 and 5 are closed and wait in that state.
The fact that the temperature of the molds 4 and 5 has decreased to the value TL can be known based on the output of the mold temperature sensor 62. However, the time S2 when the mold temperature falls from the value TL + ΔTL1 to TL can be predicted from the time constant measured in the dry cycle. Therefore, the time point when the mold temperature reaches the value TL may be recognized by measuring the time S2 from the time point when the mold temperature reaches the value TL + ΔTL1. In this case, the time S2 can be measured by the timer.

Mold reheating operation:
As described above, the open / close valve 53 is opened, and the low temperature water stored in the heat medium passage in the mold is discharged by the high temperature water. When the high temperature water is replaced with low temperature water, the open / close valve 54 is opened and the open / close valve 55 of the low temperature water pipe 35 is closed. Thereby, circulation supply of high temperature water is continued and the reheating process of a metal mold | die is advanced.
Note that the point in time when high temperature water is replaced with low temperature water can be predicted from the time constant measured in the dry cycle. Therefore, the time when the replacement of the high-temperature water is completed can be recognized by measuring the estimated time with the timer after the opening / closing valve 53 is opened.

The mold temperature control device 32 displays the measured value of the mold temperature in the above process at the lower part of the screen of FIG. 3 for each cycle of the molding process. Based on the display screen, the operator sets the high-temperature water set value (THW), the low-temperature water set value (TLW), so that the resin molding conditions by the injection molding machine are optimized and the molding cycle is minimized. The set values of the heating overshoot temperature correction value (ΔTH), the cooling undershoot temperature correction value (ΔTL1), and the high temperature heat medium supply start mold temperature correction value (ΔTL2) are corrected.

  The image display means 33 may be configured such that the upper image and the lower image in the image display panel of FIG. 3 can be switched and displayed on the same screen. In this way, the image display means 33 can be reduced in size and cost.

According to the above embodiment, the high temperature water set value (THW), cold water setpoint (TLW), heating the overshoot temperature correction value (.DELTA.TH), by setting the cooling undershoot temperature correction value (ΔTL1) appropriate Can minimize the molding cycle. Further, in the display panel of the image display means 33, the set value of the mold temperature for each molding process of the molding machine can be compared with the measured value, so that an optimal mold temperature change pattern can be easily set. Can do.

Next, a second embodiment of the mold temperature adjusting device and the mold temperature adjusting method according to the present invention will be described with reference to FIGS.
In the second embodiment, the image display means 33 and the setting means 46 shown in FIGS. 1 and 2 are omitted, and the setting display means 15a of the molding machine control device 15 has these functions. That is, the setting display means 15a includes a touch key type image display panel as shown in FIG. 3, and the image shown in FIG. 3 is displayed when the first display mode is set by the operation of the touch key or the like. Is done. In this case, as described above, the setting position of the mold temperature in the molding process, the operation start position of the timer, etc. can be designated with the touch key, and the set values of the temperature and time corresponding to the designated position can be set. A numeric keypad (not shown) can be used for input.

  The set value of the mold temperature control condition displayed on the image display panel is transferred from the molding machine control device 15 to the mold temperature control device 32, whereby the mold temperature control is executed. Then, the actual measured value of the mold temperature is transferred from the mold temperature control device 32 to the molding machine control device 15, and the actual measured value is displayed on the image display panel as illustrated in the lower part of FIG.

On the other hand, when the second display mode is set by operating a touch key or the like, an image for setting molding conditions is displayed on the image display panel. In this case, setting positions of molding conditions such as injection pressure, injection speed, and pressure holding speed can be designated with the touch keys, and set values corresponding to the designated positions can be entered with the numeric keys.
The molding machine control device 15 controls the drive hydraulic pressure of the mold opening / closing cylinder 12, the mold clamping cylinder 2a, the injection screw 7 and the like based on the set value displayed on the image display panel, and the injection pressure and the like. Are displayed on the image display panel.

  As described above, according to the second embodiment, by selecting the first display mode, the set value of the mold temperature control condition and the actual measured value of the mold temperature can be displayed. By selecting the second display mode, it is possible to display the set values of the molding conditions and the measured values such as the injection pressure and the injection speed, so that the operator's workability can be improved. Further, since it is not necessary to provide image display means and setting means in the mold temperature control device 32, the apparatus cost can be reduced.

It is a schematic diagram which shows the principal part and mold temperature control apparatus of the injection molding machine which concern on 1st Embodiment. It is a block diagram which shows the temperature control system of the metal mold | die temperature control apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the image which shows the setting value entry frame and measured value of mold temperature with respect to each operation | movement process of an injection molding machine. It is a figure which shows an example of the image which shows the actual measurement waveform of the temperature change of the metal mold | die heated and cooled with the metal mold | die simple substance. It is a schematic diagram which shows the principal part and mold temperature control apparatus of the injection molding machine which concern on 1st Embodiment. It is a block diagram which shows the temperature control system of the metal mold | die temperature control apparatus which concerns on 1st Embodiment.

Explanation of symbols

4 fixed mold 5 movable mold 10 injection unit 15 molding machine control device 15a setting display means 20 mold clamping device 23 low temperature water tank 24 high temperature water tank 25 recovery tank 26 low temperature water pump 28 high temperature water pump 32 mold temperature control device 33 Image display means 52, 53, 55 On-off valve 61 Water pressure adjusting valve 62 Mold temperature sensor 63 Low temperature water temperature sensor 64 High temperature water temperature sensor

Claims (14)

A mold temperature control device that performs temperature control of a mold by selectively flowing a high-temperature heat medium and a low-temperature heat medium at a predetermined temperature through a heat medium passage provided in the mold,
Mold temperature measuring means for measuring the temperature of the mold;
When the mold is heated, when the temperature of the mold rises from a predetermined resin filling start temperature value TH to a value TH-ΔTH obtained by subtracting the heating overshoot temperature correction value ΔTH, the high-temperature heat medium to the mold When the mold is cooled, when the temperature of the mold falls to a value TL + ΔTL1 obtained by adding a cooling undershoot temperature correction value ΔTL1 to a predetermined cooling completion mold opening start temperature TL, to the mold Mold temperature control means for stopping the supply of the low-temperature heat medium,
The heating overshoot temperature correction value ΔTH is a predicted rise temperature value that defines the supply stop time of the high-temperature heat medium so that overshoot of the mold temperature is suppressed, and the cooling undershoot temperature correction value ΔTL1 Is a predicted temperature drop value that defines the supply stop point of the low-temperature heat medium so that undershooting of the mold temperature is suppressed.   The mold temperature control means measures the temperature rise corresponding to the heating overshoot temperature correction value ΔTH by actually measuring the temperature of the mold with the mold temperature measuring means, or the temperature of the mold Is recognized by measuring the time S1 estimated to be required to increase from the value TH-ΔTH to the value TH by the time measuring means, and the temperature decrease corresponding to the cooling undershoot temperature correction value ΔTL1 is By actually measuring the temperature of the mold with the mold temperature measuring means, or by measuring the time S2 that is expected to be required for the temperature of the mold to drop from the value TL + ΔTL1 to the value TL with the time measuring means. 2. The mold temperature adjusting device according to claim 1, wherein the mold temperature adjusting device recognizes the mold temperature.   The mold temperature control means starts supplying the high-temperature heat medium to the mold when the temperature of the mold falls to the value TL + ΔTL2 (<ΔTL1), and the temperature of the mold rises to the value TH. 2. The mold temperature adjusting apparatus according to claim 1, wherein supply of the low-temperature heat medium to the mold is started at a time point.   The mold temperature control means measures the value TL + ΔTL2 by the mold temperature measurement means when the temperature of the mold falls to the value TL + ΔTL2 (<ΔTL1), or the temperature of the mold 4. The apparatus for adjusting a mold temperature according to claim 3, wherein a time SH estimated to be required to drop from the value TL + ΔTL1 to the value TL + ΔTL2 is recognized by measuring time SH. The temperature of the high-temperature heat medium, the temperature of the low-temperature heat medium, the resin filling start temperature TH, the heating overshoot temperature correction value ΔTH, the cooling completion mold opening start temperature TL, the cooling undershoot temperature correction value ΔTL1, and the high Mold temperature control condition setting means for setting the heating medium supply start temperature ΔTL2 as a mold temperature control condition;
Display means for displaying the mold temperature control conditions in the molding process, and displaying the actual temperature change of the mold in the actual molding process;
The mold temperature adjusting device according to claim 1, further comprising:   6. The mold according to claim 5, wherein the display means is configured to switch and display the mold temperature control condition and the measured temperature change on the same screen. Temperature adjustment device.   The heating overshoot temperature correction value ΔTH is predicted based on the time constant of the temperature change of the mold when the mold is heated, and the cooling undershoot temperature correction value ΔTL1 is calculated as the mold itself. 6. The mold temperature adjusting device according to claim 5, further comprising means for predicting based on a time constant of a temperature change of the mold when the mold is cooled. A mold temperature adjustment method for controlling the temperature of a mold by selectively flowing a high-temperature heat medium and a low-temperature heat medium at a predetermined temperature through a heat medium passage provided in the mold,
Measuring the temperature of the mold;
When the mold is heated, when the temperature of the mold rises to a value TH−ΔTH obtained by subtracting the heating overshoot temperature correction value ΔTH from a predetermined resin filling start mold temperature value TH, the high temperature applied to the mold is increased. Stopping the supply of the heating medium;
At the time of cooling the mold, supply of the low-temperature heat medium to the mold when the temperature of the mold drops to a value TL + ΔTL1 obtained by adding a cooling undershoot temperature correction value ΔTL1 to a predetermined cooling completion mold temperature TL And a step of stopping
The heating overshoot temperature correction value ΔTH is a predicted rise temperature value that defines the supply stop time of the high-temperature heat medium so that overshoot of the mold temperature is suppressed, and the cooling undershoot temperature correction value ΔTL1 Is a predicted temperature drop value that defines the supply stop point of the low-temperature heat medium so that undershoot of the mold temperature is suppressed. The temperature rise corresponding to the heating overshoot temperature correction value ΔTH is measured by measuring the temperature of the mold by the mold temperature measuring means or by measuring the high temperature heat retention time set value S1 by the time measuring means. The temperature decrease corresponding to the cooling undershoot temperature correction value ΔTL1 is detected by actually measuring the temperature of the mold by the mold temperature measuring means, or the temperature of the mold is the value TL + ΔTL1. 9. The method for adjusting the mold temperature according to claim 8, wherein the time S2 descending from the value TL to the value TL is recognized by measuring with a time measuring means. The time S1 is predicted based on the time constant of the temperature change of the mold when the mold is heated, and the time S2 is the temperature change of the mold when the mold is cooled. The method for adjusting the mold temperature according to claim 9, wherein prediction is performed based on a time constant. The supply of the high temperature heat medium is started when the temperature of the mold is lowered to a value TL + ΔTL2 (<ΔTL1), and the supply of the low temperature heat medium is started when the temperature of the mold is raised to a value TH. The method for adjusting the mold temperature according to claim 9, wherein the mold temperature is adjusted.   When the temperature of the mold falls to the value TL + ΔTL2 (<ΔTL1), the value TL + ΔTL2 is actually measured by the mold temperature measuring means, or the low temperature heat retention time set value SH is timed by the time measuring means. The method for adjusting a mold temperature according to claim 11, wherein the mold temperature is recognized. The temperature of the high-temperature heat medium, the temperature of the low-temperature heat medium, the resin filling start mold temperature TH, the heating overshoot temperature correction value ΔTH, the cooling completion mold temperature TL, the cooling undershoot temperature correction value ΔTL1, and A step of setting a high temperature heat medium supply start mold temperature correction value ΔTL2 as a mold temperature control condition;
  A second image showing a change in the measured temperature of the mold in the actual molding process is displayed on the display means with a first image formed by adding the mold temperature control condition on the reference mold temperature curve in the molding process. Displaying an image on the display means;
The method for adjusting a mold temperature according to claim 8, further comprising: The heating overshoot temperature correction value ΔTH is predicted on the basis of a time constant of the mold temperature change when the mold unit is heated, and the cooling undershoot temperature correction value ΔTL1 is used to cool the mold unit. 9. The method for adjusting a mold temperature according to claim 8, wherein the mold temperature is predicted based on a time constant of the mold temperature change at the time.

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