JPH0584747A - Device for adjusting temperature of mold of plastic molding machine - Google Patents

Abstract

PURPOSE:To reduce the mixing amount of the high and low temp. fluids allowed to flow to the mold of a plastic molding machine at the time of the changeover of the temp. of the mold in a mold temp. adjustor for heating or cooling the mold during a molding process. CONSTITUTION:A changeover manifold 11 changing over high and low temp. fluids to allow either one of them to flow to a mold is arranged to the fixing plate 4 and movable plate 5 of the mold. By this constitution, as compared with such a case that the changeover manifold 11 is placed in the vicinity of a fluid temp. adjustor 10, the amount of the fluid remaining in the mold part ahead of the changeover manifold can be reduced to a large extent. The changeover timing of the changeover valve provided to the changeover manifold is controlled by a timer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a metal mold capable of selectively supplying a fluid for heating or cooling a metal mold of a plastic molding machine to two levels of high temperature and low temperature during the molding process. The present invention relates to a mold temperature adjusting device.

[0002]

2. Description of the Related Art Conventionally, in a plastic injection molding machine or the like, the temperature of the mold has been adjusted so as to be a constant temperature during the process. However, from the viewpoint of improving productivity, it has recently become necessary to significantly shorten the molding cycle, and in order to significantly shorten the molding cycle, it is necessary to rapidly lower the mold temperature after filling the mold with resin. It is necessary to promote cooling. On the other hand, such a rapid change of the mold temperature takes too much time to change the mold temperature because the heat capacity of the mold is large. When the mold temperature is raised or lowered by switching between the high-temperature fluid and the low-temperature fluid through the cooling groove of the mold, the fluid to be replaced remaining in the mold part at the time of switching between the high-temperature fluid and the low-temperature fluid becomes the replacement fluid circuit. There is a problem that the high temperature fluid and the low temperature fluid are mixed with each other, and it is technically difficult to solve this problem. Here, the fluid refers to a medium such as water or oil used for cooling or heating the mold.

By the way, recently, the above-mentioned problem of mold heat capacity is solved by providing multiple cooling grooves in the vicinity of a cavity of a molded product, as disclosed by the inventors of the present invention in Japanese Patent Application No. 2-41177. Although it has become possible, the problem that the high-temperature fluid and the low-temperature fluid are mixed still remains unsolved. That is, when the high temperature fluid and the low temperature fluid are mixed, the temperatures of the high temperature fluid and the low temperature fluid change greatly, so that the desired mold temperature change cannot be achieved, and the energy loss corresponding to the mixture of the high temperature fluid and the low temperature fluid is large. That causes a fatal defect.

[0004]

As described above, in the prior art, the temperature of the mold is adjusted to two levels, high temperature and low temperature, during the molding process by switching between the high temperature fluid and the low temperature fluid. In this case, there is a problem in that the high temperature fluid and the low temperature fluid are mixed with each other at the time of switching, so that a desired mold temperature change cannot be achieved and energy loss is large.

Therefore, according to the present invention, 1) a plurality of switching valves for switching between a high temperature fluid and a low temperature fluid are installed on a mold mounting plate of a molding machine or in the vicinity thereof. 2) The operation timing of each return side switching valve for the high temperature fluid and the low temperature fluid is delayed from the operation timing of each supply side switching valve by any of the following means. A) Delay by the time set by the timer. B) A temperature detecting means is provided in the fluid outlet passage of the mold to detect when the fluid temperature of the passage reaches a set temperature when switching from high temperature to low temperature or a set temperature when switching from low temperature to high temperature. Delay to the point. 3) The fluid tank has any structure. B) The tanks that store the high-temperature fluid and the low-temperature fluid each have a change in the amount of stored fluid that exceeds the capacity of the fluid to be replaced that remains in the fluid passage between the inlet-side switching valve and the outlet-side switching valve of the fluid in the mold. Be tolerable. (B) In the same tank, a high temperature fluid can be accommodated on the upper side and a low temperature fluid can be accommodated on the lower side without a boundary wall between the two, and a discharge port and an inflow port for the fluid are provided in each accommodating portion. It is an object of the present invention to solve the above-mentioned problems and to provide a mold temperature adjusting device in which the amount of the high temperature fluid and the low temperature fluid mixed is extremely small by taking technical measures such as the above.

[0006]

For this reason, the present invention provides a mold by selectively switching between a high temperature fluid and a low temperature fluid in a mold of a molding machine during the molding process of a plastic molded product by the molding machine. In the mold temperature adjusting device for controlling the temperature of 1., a switching valve for switching between the high temperature fluid and the low temperature fluid is installed on the mold mounting plate of the molding machine or in the vicinity thereof. It is a means for solving the problem.

Further, according to the present invention, when switching between the high temperature fluid and the low temperature fluid, the operation timing of each return side switching valve of the fluid is delayed by a predetermined time from the operation timing of each supply side switching valve. This is a means for solving the problem.

Further, according to the present invention, during the molding process of a plastic molded product by the molding machine, the temperature of the mold is controlled by selectively switching a high temperature fluid and a low temperature fluid to flow in the mold of the molding machine. In the mold temperature adjusting device described above, the tank for storing the same high temperature fluid and the same low temperature fluid has a capacity equal to or greater than the capacity of the fluid to be replaced remaining in the fluid passage between the inlet side switching valve and the outlet side switching valve of the fluid in the mold. The change in the amount of stored fluid is allowed in the tank, and this is a means for solving the problem.

[0009]

According to the present invention, 1) By installing a plurality of switching valves for switching between the high temperature fluid and the low temperature fluid on the mold mounting plate of the molding machine or in the vicinity thereof, those switching valves are mounted on the mold. The amount of fluid to be replaced when switching between the high temperature fluid and the low temperature fluid in the mold is significantly reduced as compared with the case where the fluid is installed away from the board.

2) By delaying the operation timing of each return-side switching valve for the high-temperature fluid and the low-temperature fluid with respect to the operation timing of each supply-side switching valve, the fluid to be replaced in the mold can be heated to a high temperature. When the temperature of the fluid is low and the temperature of the fluid is low, the fluid can be returned to the circuit of the low temperature fluid, and the amount of the high temperature fluid and the low temperature fluid mixed is extremely small. Particularly, when the method of delaying the operation timing of the return side switching valve is changed as follows, the operation also differs as follows. B) When the operation timing is delayed by the set time of the timer, the delay time can be changed arbitrarily, which makes it possible to find the delay time that minimizes the mixing amount of the high temperature fluid and the low temperature fluid. To do. B) In the case of means for providing a temperature detection means in the fluid outlet passage of the mold and detecting when the fluid temperature of the passage reaches the set temperature and delaying it until that time, the driver does not need to adjust the delay time. , The switching valve is automatically delayed.

3) By configuring the fluid tank so that the storage amount change of the high temperature fluid and the low temperature fluid by the amount of the fluid to be replaced in the mold can be allowed, the fluid to be replaced is transferred to the high temperature circuit when it is hot. In the case of low temperature, when returned to the low temperature circuit, it is possible to absorb the change in each fluid amount caused thereby. Especially, the operation is different as follows depending on the structure of the tank. B) In tanks in which high-temperature fluid tanks and low-temperature fluid tanks are provided separately and each tank can tolerate changes in the amount of stored fluid, the changes in the amount of stored fluid in each tank are large.
It is possible to reliably return the fluid to be replaced in the mold to the respective circuits regardless of whether the fluid is hot or cold. B) In the same tank, a tank that can store a high temperature fluid on the upper side and a low temperature fluid on the lower side without a boundary wall between them,
Since the boundary surface of the high temperature fluid and the low temperature fluid moves up and down in the tank according to the change in the mutual fluid amount, it is possible to cope with the movement of both the high temperature and the low temperature replaced fluid in one mold of the tank.

As described above, according to the present invention, the amount of the fluid to be replaced in the mold can be reduced by the constitution of the above item 1) 2)
With the construction of item (1), it is possible to prevent the high temperature fluid and the low temperature fluid from mixing in the mold, and with the construction of item 3), the movement of the fluid to be replaced in the mold can be absorbed by the tank.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an injection molding machine according to the embodiment of the present invention. 1 is an injection device, 2 is a raw material hopper, and 3 is a screw cylinder. The raw material charged from the raw material hopper 2 is plasticized by the screw cylinder 3 and injected into the molds 8 and 9 by the injection operation of the injection device 1. Reference numeral 4 is a fixed platen, 5 is a movable platen, and a fixed side mold 8 and a movable side mold 9 are attached to the fixed platen 4 and the movable platen 5, respectively. 6 is a mold clamping ram,
A mold clamping cylinder 7 is used to open and close the mold. Reference numeral 10 is a fluid temperature controller, and pipings 21A to 24A and 21B to 24 are provided between the fluid temperature controller and the switching manifolds 11 and 12.
Connected at B. The switching manifolds 11 and 12 are attached to the fixed platen 4 and the movable platen 5, respectively. In addition, the pipes 31A, 3 from the switching manifold 11 to the fixed side mold 8
2A is connected, and pipes 31B and 32B are connected from the switching manifold 12 to the movable side mold 9.

FIG. 2 is a perspective view of the switching manifold 11.
Each of the switching valves H1A, L1A, H2A, and L2A is attached to the bracket 15 with U bolts 16 via pipes 17 and 18. The switching manifold 12 has the same structure. As shown in FIGS. 1 and 2, by installing the switching manifolds 11 and 12 on the fixed platen 4 and the movable platen 5, which are attached to the mold, as compared with the case where these switching manifolds are placed near the fluid temperature controller 10. , The amount of fluid remaining in the die portion ahead of each switching manifold can be greatly reduced.

FIG. 3 shows the structure of the fluid tank incorporated in the fluid temperature regulator 10, which has the same structure for both the high temperature fluid and the low temperature fluid. In the figure, reference numeral 60 is a tank in which the fluid 68 is stored. 61 is a float, and when the height of the stored fluid 68 falls below S ₁ , the float 6
1 is lowered, the plug 62 is opened, and the supply fluid 6 is supplied from the water supply pipe 63.
5 flows in. On the other hand, when the height of the stored fluid 68 rises above S ₂ , it flows out from the drain pipe 64 to the outside 66. Therefore, the height of the stored fluid 68 is maintained between S ₁ and S ₂ , and the stored fluid amount change ΔV during that period is allowed. A discharge pump 50 sucks the stored fluid 68 and discharges it to the discharge port 51, and the fluid flows in from the other inflow port 52. When this tank is a high temperature fluid tank, a heater (not shown) is incorporated to increase the temperature of the fluid, and when it is a low temperature fluid tank, a cooling circuit (not shown) is incorporated to cool the fluid. Used for.

FIG. 4 shows a temperature adjusting fluid circuit, 10 is a fluid temperature adjusting machine, and a high temperature fluid unit 10H is provided in the adjusting machine.
Also, a low temperature fluid unit 10L is provided, and a high temperature fluid and a low temperature fluid are discharged from these units and returned after circulation. 19H and 19L are a high temperature fluid discharge pipe and a low temperature fluid discharge pipe, respectively, and 20H and 20L are a high temperature fluid return pipe and a low temperature fluid return pipe, respectively.
Is a flow control valve. Each of the fluid tanks described in FIG. 3 is incorporated in each of the high temperature fluid unit 10H and the low temperature fluid unit 10L, and the discharge port 51 of FIG. 3 is connected to the high temperature or low temperature fluid discharge pipe 19H or 19L of FIG. 52 is the hot or cold fluid return pipe 20H or 20 of FIG.
Equivalent to L.

Further, in FIG. 4, the electromagnetic switching valves H1A, L1A, H2A, L2A for the fixed side mold are incorporated in the switching manifold 11 as described with reference to FIG. L1B, H2B, L2B are
It is incorporated in the switching manifold 12. Further H3
L3 is an electromagnetic switching valve for bypassing the high temperature fluid and the low temperature fluid, respectively. All of these electromagnetic switching valves are switched between two positions, open and closed, and open when energized (ON). The high temperature fluid discharges the high temperature fluid discharge pipe 19 when the electromagnetic switching valve H3 is OFF, that is, when it is closed.
One from H flows into the fixed side mold cooling groove 35A through the pipe 21A, the switching valve H1A and the pipe 31A, and the other from the pipe 2
1B, the switching valve H1B, and the pipe 31B to flow into the movable-side mold cooling groove 35B. And from the cooling groove 35A to the pipe 3
2A, the switching valve H2A, the pipe 23A, and the other from the cooling groove 35B to the pipe 32B, the switching valve H2B, the pipe 23B.
And return to the return pipe 20H. The electromagnetic switching valve H3 is O
N, that is, when the high temperature fluid is open, the high temperature fluid flows from the discharge pipe 19H
Return to the return pipe 20H via 3. Further, when the flow rate adjusting valve 27 throttles the flow rate to the mold by the flow rate adjusting valves 25 and 26, the pressure in the discharge pipe 19H rises too much when the switching valve H3 is turned off, that is, closed and the fluid is sent to the mold. To prevent
Return pipe 20H from the discharge pipe 19H through the flow rate adjusting valve 27.
It adjusts the flow rate to escape. Also, the circuit for the cryogenic fluid is constructed in exactly the same way.

FIG. 5 is a sequence showing a mold temperature adjustment mode in the injection molding process. In the figure, the temperature is switched from the high temperature to the low temperature after the set time of the timer 1 from the start of the injection filling process, and the low temperature is switched to the high temperature after the set time of the timer 2 from the start of the mold opening process. By switching the temperature adjustment mode between high temperature and low temperature in this way, the mold temperature is raised during injection filling to facilitate the resin flow in the mold, and in the subsequent cooling process the mold temperature is lowered to cool the resin. Promote. In the figure, the timer 1 times out and switches from high temperature to low temperature in the injection filling process. This is due to the time lag between the sequence switching and the actual mold temperature change. Therefore, the actual mold temperature becomes low only after the injection filling process is completed.

FIG. 6 shows each electromagnetic switching valve, particularly electromagnetic switching valves H1A, H1B, H in switching from a high temperature to a low temperature and from a low temperature to a high temperature in the mold temperature adjusting mode of FIG.
2A, H2B, L1A, L1B, L2A, L2B ON
A sequence showing how to shift OFF, which is a characteristic part of the present invention. In FIG. 6, switching from high temperature to low temperature will be described. First, the switching valve L for low temperature fluid bypass.
3. The high temperature fluid inlet switching valves H1A, H1B are turned off, and at the same time, the high temperature fluid cutting / entry switching valve H3 and the low temperature fluid inlet switching valves L1A, L1B are turned on to keep the fluid flowing into the mold from high temperature. Change to low temperature. At this time, since the switching valves H2A, H2B, L2A, L2B at the fluid outlets have not been switched yet, the high temperature fluid remaining in the mold part directly returns to the high temperature fluid circuit through the switching valves H2A, H2B. Then, the changeover valves L3, H1A, H1B, H3,
The switching valve H2A is turned off and the switching valve L2A is turned on by the timer A after the switching of L1A and L1B is started. Similarly, the switching valve H2B is turned off and the switching valve L2B is turned on by the timer B. Here, the timers A and B are
In each of the fixed side mold and the movable side mold, an appropriate time is set so that the inflowing low temperature fluid does not flow out of the high temperature fluid outlet switching valves H2A and H2B into the high temperature circuit. The same applies when switching from low temperature to high temperature. According to the above-mentioned sequence, when switching between the high temperature and the low temperature, most of the fluid to be replaced that remains in the mold part returns to the high temperature circuit if it is high temperature, and returns to the low temperature circuit if it is low temperature.
The amount of the high temperature fluid and the low temperature fluid mixed is extremely small.
As described above, the amount of fluid to be replaced in the mold portion is reduced as shown in FIGS. 1 and 2, so that the setting of the timers A and B can be shortened and the loss time required for switching can be reduced.

FIG. 7 shows an example of trial calculation of the relationship between the fluid temperature change in the tank and the mixed fluid amount when switching between the high temperature fluid and the low temperature fluid. In the example of FIG.
Uses cryogenic fluid. The amount of fluid to be replaced in the mold is 2
There is 500 cm ^3, and if the fluid to be replaced is mixed in the fluid circuit on the replacement fluid side after switching due to switching between the high temperature fluid and the low temperature fluid, the fluid temperature in the tank on the replacement fluid side will change by 5 ° C. On the other hand, when the means of this embodiment is applied, the amount of the mixed fluid becomes 500 cm ³ or less even if a slight leak is seen, and the temperature change of the fluid in the tank is 1 or less.
It will be less than ℃ and it will be greatly improved. When the temperature change of the fluid in the tank is small in this way, the mold temperature can be adjusted with high accuracy, and the quality of the molded product becomes stable.

Instead of the timers A and B for shifting the operation timing of the electromagnetic switching valve described in FIGS. 8 and 6, the outlet temperature of the fluid for temperature control of the actual mold is measured and the switching valve of the fluid outlet is switched. It shows the principle. In the figure, the outlet temperature of the temperature adjusting fluid of the mold is switched from the high temperature T _H to the low temperature T _{L and then} to the high temperature T _H again. When switching from a high temperature to low temperature, slightly lower temperature T _HL higher temperature T _H in a steady state
Is set, and the switching valves L3 and H1 are first set in the same manner as in FIG.
A, OFF H1B is OFF, the switching valve H3, L1A, L1B is OFF, the next actual when the fluid outlet temperature of the mold became T _HL to (at point P) switching valve H2A or H2B
Then, the switching valve L2A or L2B is switched to ON. Since the fluid outlet of the mold is in both the fixed side mold and the movable side mold, the respective temperatures are measured by the temperature sensors 41 and 42 in FIG. 4, and the fixed side switching valves H2A and L2A and the movable side mold are The operation timing is determined separately from the switching valves H2B and L2B. Further, when switching from the low temperature to the high temperature, the temperature _TLH which is slightly lower than the low temperature _{TL in the} steady state is set and the same operation is performed. In this way, by using the temperature sensor to detect when the outlet temperature of the actual mold temperature control fluid reaches the set value, and by determining the operation timing of the electromagnetic switching valve,
It is not necessary for the driver to perform the adjustments such as the timers A and B in FIG. 6, and the operation of the electromagnetic switching valve can be automatically shifted even if the mold or the temperature adjustment condition is changed. However, after detecting the time when the fluid outlet temperature of the mold reaches the set value, the timing may be further delayed by a timer to set a more appropriate switching valve operation timing.

FIG. 9 shows another embodiment of a tank for storing hot fluid and cold fluid. In the figure, reference numeral 80 denotes a tank, which is shared by the high temperature fluid 88 and the low temperature fluid 90. 70 is a pump for high temperature fluid, which discharges the high temperature fluid to the discharge pipe 19H,
Return from 0H to the tank. Similarly, 75 is a low temperature fluid pump that discharges the low temperature fluid to the discharge pipe 19L and returns it from the return pipe 20L to the tank. As described in the first embodiment, when the high temperature and the low temperature are switched, the amount of the fluid to be replaced in the die part is the high temperature circuit,
As it goes in and out of the low temperature circuit, the boundary surface between the high temperature fluid and the low temperature fluid in this tank moves up and down between the heights S _H and S _L to allow the fluid amount change ΔVc therebetween. Further, reference numeral 82 is an electromagnetic switching valve for fluid replenishment, which is opened when the liquid level sensor 81 detects that the level of the stored fluid is too low.
Replenish the fluid from 1. Reference numeral 83 is a relief valve which is automatically opened when the pressure in the tank rises too much to drain the fluid in the tank to 92. As described above, in the tank of this embodiment, one tank can share the high temperature fluid and the low temperature fluid,
In addition, since the fluctuation of the boundary liquid level between the two is allowed, the system can be constructed very economically. Even if the upper high temperature fluid and the lower low temperature fluid come into contact with each other via the liquid level as in this tank, the thermal conductivity of water is small, and since the upper temperature is high, there is no convective heat transfer. The heat transfer between the cryogenic fluids is slight and no problem.

[0023]

As described above in detail, according to the present invention, 1) by installing a plurality of switching valves for switching between a high temperature fluid and a low temperature fluid on a die mounting plate of a molding machine or in the vicinity thereof, The amount of fluid to be replaced when switching between high temperature and low temperature in the mold becomes small. Further, when the switching valve is directly attached to the mold, the switching valve needs to be replaced every time the mold is replaced, whereas in this method, the switching valve does not need to be replaced even if the mold is replaced. 2) Replacing the die part by appropriately delaying the operation of each return-side switching valve for high-temperature fluid and low-temperature fluid with respect to the operation of each supply-side switching valve by a timer or a temperature detecting means at the fluid outlet of the die part. The fluid with a high temperature is returned to the high temperature circuit, and the fluid with a low temperature is returned to the low temperature circuit, and the mixture of the high temperature fluid and the low temperature fluid is extremely reduced. 3) Each tank for high-temperature fluid and low-temperature fluid is configured to allow fluctuations in the amount of stored fluid, or a tank shared by both fluids stores the high-temperature fluid above and the low-temperature fluid below to allow vertical movement of the interface between the two. With this configuration, the tank can absorb the return amount of the fluid to be replaced in the mold part. 4) As a result, when the mold temperature is adjusted by switching between the high temperature fluid and the low temperature fluid, the amount of the high temperature fluid and the low temperature fluid that are mixed is extremely small, and therefore the energy loss due to the mixture of the two is small and stable molding is possible. It is possible to obtain excellent effects such as

[Brief description of drawings]

FIG. 1 is a plan view of an injection molding machine according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a switching manifold installed on the mold mounting plate (fixed plate) of FIG.

FIG. 3 is a structural schematic diagram of individual tanks for storing a high temperature fluid and a low temperature fluid.

FIG. 4 is an overall temperature control fluid circuit diagram.

FIG. 5 is a sequence diagram showing a high temperature and a low temperature in a mold temperature adjustment mode in an injection molding process.

FIG. 6 is a sequence diagram showing how to shift the operation of the electromagnetic switching valve when switching between high temperature and low temperature.

FIG. 7 is a graph showing the relationship between the fluid temperature change in the tank and the mixing amount of the high temperature fluid and the low temperature fluid when switching between the high temperature and the low temperature.

FIG. 8 is a principle diagram for determining an operation time point of an electromagnetic switching valve by detecting an outlet temperature of a temperature adjusting fluid in a mold.

FIG. 9 is a schematic diagram of another embodiment of a tank containing hot and cold fluids.

[Explanation of symbols]

4 Fixed Plate (Mold Mounting Plate) 5 Movable Plate (Mold Mounting Plate) 8 Fixed Side Mold 9 Movable Side Mold 10 Fluid Temperature Controller 11, 12 Switching Manifold 60 Tank 80 Shared Tank H1A, H1B, H2A, H2B , H3 High temperature fluid side solenoid switching valve L1A, L1B, L2A, L2B, L3 Low temperature fluid side solenoid switching valve

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[Procedure amendment]

[Submission date] December 6, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Instead of the timers A and B for shifting the operation timing of the electromagnetic switching valve described in FIGS. 8 and 6, the outlet temperature of the fluid for temperature control of the actual mold is measured and the switching valve of the fluid outlet is switched. It shows the principle. In the figure, the outlet temperature of the temperature adjusting fluid of the mold switches to a low temperature T _L from hot T _H, switched later also switching to a high temperature T _H. When switching from a high temperature to low temperature, high temperature T _H than the slightly lower temperature T of the steady state
_HL is set, and first, as in FIG. 6, the switching valves L3, H
1A, H1B is OFF, switching valves H3, L1A, L1B
Is turned off, and then the temperature of the fluid outlet of the mold is actually _THL.
When it becomes, the switching valve H2A or H2B is turned off (at the point P).
To F, the switching valve L2A or L2B is switched to ON. Since the fluid outlet of the mold is in both the fixed side mold and the movable side mold, the respective temperatures are measured by the temperature sensors 41 and 42 in FIG. 4, and the fixed side switching valves H2A and L2A and the movable side mold are The operation timing is determined separately from the switching valves H2B and L2B. Also when switching from a low temperature to a high temperature, it performed similarly by setting the temperature T _LH have slightly higher than the low temperature T _L in the steady state. In this way, by using the temperature sensor to detect when the outlet temperature of the actual mold temperature control fluid reaches the set value, and by determining the operation timing of the electromagnetic switching valve,
It is not necessary for the driver to perform the adjustments such as the timers A and B in FIG. 6, and the operation of the electromagnetic switching valve can be automatically shifted even if the mold or the temperature adjustment condition is changed. However, after detecting the time when the fluid outlet temperature of the mold reaches the set value, the timing may be further delayed by a timer to set a more appropriate switching valve operation timing.

Claims (3)

[Claims] 1. A mold for controlling the temperature of a mold by selectively switching a high-temperature fluid and a low-temperature fluid to flow in a mold of the molding machine during a molding process of a plastic molded product by the molding machine. A mold temperature adjusting device for a plastic molding machine, characterized in that, in the temperature adjusting device, a switching valve for switching between the same high temperature fluid and the same low temperature fluid is installed on a mold mounting plate of the molding machine or in the vicinity thereof. 2. The switching timing of each return side switching valve of the fluid is delayed by a predetermined time from the switching timing of each supply side switching valve when switching between the high temperature fluid and the low temperature fluid. 1. A mold temperature adjusting device for a plastic molding machine according to 1. 3. A mold for controlling the temperature of the mold by selectively switching a high temperature fluid and a low temperature fluid to flow through the mold of the molding machine during the molding process of the plastic molded product by the molding machine. In the temperature control device, the tank that stores the same high-temperature fluid and the same low-temperature fluid has a storage fluid that is equal to or larger than the volume of the fluid to be replaced that remains in the fluid passage between the fluid inlet-side switching valve and the outlet-side switching valve of the mold. A mold temperature adjusting device for a plastic molding machine, characterized in that it has a structure in which a change in quantity can be allowed in a tank.