KR101954165B1 - A method of controlling an amount of heat by an inverter pump in a plastic resin injection molding - Google Patents

Abstract

The present invention relates to a method of controlling quantity of heat by an inverter pump in plastic resin injection molding. More specifically, the present invention relates to a method of controlling quantity of heat by an inverter pump in plastic resin injection molding, which not only enables heating and cooling modes to be controlled by including a heater for heating cooling water and a chiller for cooling a heat medium such that the cooled heat medium is mixed with a circulating heat medium to lower temperature of the heat medium in order to allow molds for injecting a plastic resin to maintain a preset allowable temperature range, but also can continuously inject a plastic resin with a constant level, can prevent the generation of defects and can extend lifespan of a mold by controlling quantities of heat required in each of a plurality of molds and the temperature difference between an inflow and an outflow of the heat medium flown in and flown out of each of the molds such that the temperature of each mold can be maintained within the preset allowable temperature range at all times.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an amount of heat generated by an inverter pump in a plastic resin injection molding,

The present invention relates to a plastic resin injection molding machine capable of preventing the extension of the life of a metal mold and the defects of a finished product by allowing a metal mold to be operated at a predetermined temperature required for injection in a injection molding of a plastic resin, And a method of controlling the amount of heat by the pump.

In general, an injection mold provided in an injection molding machine and using a molten resin to mold a desired product always maintains a constant temperature so as not to overcool and overheat, thereby preventing the production of defective products due to temperature differences and changes .

One of the conventional examples for keeping the injection mold at a constant temperature is as follows. The injection mold is divided into a movable mold and a stationary mold. The movable mold is provided with a movable side cooling water supply manifold and a movable side cooling water discharge manifold And the stationary side cooling water supply manifold and the stationary side cooling water discharge manifold are connected to the stationary mold through the cooling water line.

However, such a conventional configuration can not maintain the temperature of the specific cooling flow path and the temperature of the hot air flow path of the movable mold and the stationary mold at a precise constant temperature, so that the life of the injection mold is shortened and product defects due to overcooling and overheating There is a problem that it occurs in a large amount.

In other words, in order to use the injection mold for a long time and to eliminate the production of defective products according to the temperature, it is necessary to keep the specific cooling flow path and the warm flow path, which affect the quality, Is controlled to be maintained.

Overcooling and overheating of the injection mold not only result in incomplete molding of the product but also cause a delay in the molding time. Among them, the subcooling is the most influential factor on the life of the injection mold and the product failure. very important.

Korea Registered Utility Model No. 20-0363040 (Registered on September 14, 2004)

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a plurality of mold internal cooling channels and temperature control channels for injecting plastic resin, A plurality of circulation lines are formed for each of the molds so that the heating and cooling can be performed at the same time, and the heating medium for the heater is heated and the cooling water (cooled heating medium) through the chiller is mixed with the circulating heating medium. And the temperature difference after the heating medium inlet / outlet is controlled to be the predetermined heat quantity and the predetermined temperature difference, the respective molds are maintained at the predetermined temperature and the injection process is performed, The plastic resin which can extend the life of the mold while reducing the defective rate of entry In Ex molded to provide a heat quantity control method by the drive pump.

Other objects and advantages of the present invention will be described hereinafter and will be understood by the embodiments of the present invention. Further, the objects and advantages of the present invention can be realized by the means and the combination shown in the claims.

SUMMARY OF THE INVENTION The present invention, as a means for solving the above problems,
A stationary mold 10 and a movable mold 20 for plastic resin injection;
A circulation line (30) installed in each of the stationary mold (10) and the movable mold (20) and circulating the heating medium;
An inverter pump (31) installed in the circulation line (30) for transferring the heating medium;
A first line 41 in which a first control valve V1 is installed in the circulation line 30 and a heater 32 is installed to heat the heating medium;
A second line (42) in which a second control valve (V2) is installed in the circulation line (30) and circulates the heat medium through the heater (32);
A third control valve V3 is installed in the circulation line 30 and is connected to the chiller 50 so that the cooled heat medium circulated through the chiller 50 is mixed with the circulating heat medium, Line 43;
Main temperature sensors (61, 62) for measuring temperatures of the stationary mold (10) and the movable mold (20);
Outlet temperature sensors 71 and 72 respectively installed at the inflow and outflow ports of the circulation lines 30 provided in the stationary mold 10 and the movable mold 20 for measuring a temperature difference between the inflow and outflow of the heating medium; Lt; / RTI >
The fixed mold 10 and the movable mold 20 are controlled by the control unit 80 to control the inverter pump 31 for controlling the flow rate and a plurality of The first, second, and third lines L1, L2, and L3 are automatically selected through control of the control valves V1, V2, V3, and V4 to operate in any one of heating, cooling,
When the measured calorie amount of each of the dies is compared with the preset calorie amount and the measured calorie amount is different from the preset calorie amount, the flow amount of the heating medium is increased or decreased through the inverter pump 31, A step (S10) of controlling the heat medium flow rate until the allowable range is reached;
If the measured calorie of each mold reaches the preset calorie tolerance range in step S10,
Output temperature difference between the respective molds is compared with the preset temperature difference through the above-mentioned inflow and outflow temperature sensors (71, 72)
The flow rate of the heating medium is increased through the inverter pump 31 to adjust the temperature of the second line 42 when the measurement inflow and outflow temperature difference of each of the molds reaches the predefined temperature difference allowable range, The heat medium is circulated without using the heater 32 and the chiller 50 to control the flow rate of the heat medium,
When the measured inflow and outflow temperature difference of each metal mold reaches the predetermined temperature difference tolerance range by reducing and controlling the flow rate of the heating medium through the inverter pump 31 when the measured inflow and outflow temperature difference is smaller than the preset temperature difference, So that the heating medium is circulated without using the heater 32 and the chiller 50 so that the flow rate and temperature difference of the heating medium are controlled,
(S20), when the measured calorie value of each of the molds falls within the allowable range of the preset calorie amount and the measured inflow and outflow temperature difference also falls within the allowable range of the preset temperature difference, the mold injection is completed

The predetermined heat quantity and the preset temperature difference of each of the stationary mold 10 and the movable mold 20 are kept within the allowable range at the same time so that defects of the injection product are not generated.

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As described above, the present invention has the effect of controlling the temperatures of the stationary mold and the movable mold used for plastic resin injection, respectively, and maintaining the predetermined temperature of each mold.

Further, the present invention has an effect that each of the dies is always kept at a predetermined temperature individually by controlling the amount of heat required by each of a plurality of dies used for plastic resin injection and the temperature difference between the heat medium inlet and outlet.

Further, in the present invention, a plurality of circulation lines through which the heating medium flows are provided for each of the molds, so that the heating and cooling are simultaneously performed in a single mold, and the temperature of the mold is maintained at a predetermined temperature.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an embodiment in which a plastic resin injection mold according to an embodiment of the present invention is operated in a heating mode and a cooling mode at the same time, and the process is progressed so as to be maintained at a predetermined temperature of the mold.
2 and 3 are schematic diagrams of a plastic resin injection mold according to an embodiment of the present invention, in which the flow rate of a heating medium is controlled by an interferometer pump in order to adjust a heat quantity of a mold for maintaining a predetermined temperature of the metal mold. .

Before describing in detail several embodiments of the invention, it will be appreciated that the application is not limited to the details of construction and arrangement of components set forth in the following detailed description or illustrated in the drawings. The invention may be embodied and carried out in other embodiments and carried out in various ways. It should also be noted that the device or element orientation (e.g., "front," "back," "up," "down," "top," "bottom, Expressions and predicates used herein for terms such as "left," " right, "" lateral, " and the like are used merely to simplify the description of the present invention, Or that the element has to have a particular orientation. Also, terms such as " first "and" second "are used herein for the purpose of the description and the appended claims, and are not intended to indicate or imply their relative importance or purpose.

The present invention has the following features in order to achieve the above object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

According to one embodiment of the present invention,
A stationary mold 10 and a movable mold 20 for plastic resin injection;
A circulation line (30) installed in each of the stationary mold (10) and the movable mold (20) and circulating the heating medium;
An inverter pump (31) installed in the circulation line (30) for transferring the heating medium;
A first line 41 in which a first control valve V1 is installed in the circulation line 30 and a heater 32 is installed to heat the heating medium;
A second line (42) in which a second control valve (V2) is installed in the circulation line (30) and circulates the heat medium through the heater (32);
A third control valve V3 is installed in the circulation line 30 and is connected to the chiller 50 so that the cooled heat medium circulated through the chiller 50 is mixed with the circulating heat medium, Line 43;
Main temperature sensors (61, 62) for measuring temperatures of the stationary mold (10) and the movable mold (20);
Outlet temperature sensors 71 and 72 respectively installed at the inflow and outflow ports of the circulation lines 30 provided in the stationary mold 10 and the movable mold 20 for measuring a temperature difference between the inflow and outflow of the heating medium; Lt; / RTI >
The fixed mold 10 and the movable mold 20 are controlled by the control unit 80 to control the inverter pump 31 for controlling the flow rate and a plurality of The first, second, and third lines L1, L2, and L3 are automatically selected through control of the control valves V1, V2, V3, and V4 to operate in any one of heating, cooling,
When the measured calorie amount of each of the dies is compared with the preset calorie amount and the measured calorie amount is different from the preset calorie amount, the flow amount of the heating medium is increased or decreased through the inverter pump 31, A step (S10) of controlling the heat medium flow rate until the allowable range is reached;
If the measured calorie of each mold reaches the preset calorie tolerance range in step S10,
Output temperature difference between the respective molds is compared with the preset temperature difference through the above-mentioned inflow and outflow temperature sensors (71, 72)
1) When the measured inflow / outflow temperature difference is larger than the preset temperature difference, the flow rate of the heating medium is increased and controlled through the inverter pump 31, 42 to circulate the heating medium without using the heater 32 and the chiller 50 to control the heating medium flow rate,
2) When the measured inflow / outflow temperature difference is smaller than the preset temperature difference, the flow rate of the heating medium is reduced and controlled through the inverter pump 31, The heat medium is circulated without using the heater 32 and the chiller 50 by using the heater 42 to adjust the flow rate and temperature difference of the heat medium,
(S20) that the mold injection is completed when the measured calorific value of each of the molds falls within the allowable range of the preset calorie amount and the measured inflow and outflow temperature difference also falls within the allowable range of the predetermined temperature difference

The predetermined heat quantity and the preset temperature difference of each of the stationary mold 10 and the movable mold 20 are kept within the allowable range at the same time so that defects of the injection product are not generated.

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Hereinafter, a method of controlling the amount of heat by the inverter pump in the plastic resin injection molding according to a preferred embodiment will be described in detail with reference to FIGS. 1 to 3. FIG.

As shown in the figure, in the plastic resin injection molding according to the present invention, the method of controlling the heat quantity by the inverter pump includes the fixed mold 10, the movable mold 20, the circulation line 30, the inverter pump 31, 41, a second line 42, a third line 43, main temperature sensors 61, 62, and inlet / outlet temperature sensors 71, 72.

The stationary mold 10 and the movable mold 20 are upper and lower molds for plastic resin injection. Each of the molds is provided with a circulation line 30 to be circulated through the circulation line 30, (Fixed mold 10 and movable mold 20, hereinafter referred to as 'each mold' for convenience of explanation) are heated according to the temperature of the heating medium (water) , Or the mold is cooled and the temperature is lowered.

In addition, only the single circulation line 30 is formed in each of the stationary mold 10 and the movable mold 20 so that the temperatures of the respective molds can be adjusted. However, in the present invention, Separate circulation lines 30 are separately provided on the right side and separate circulation lines 30 are separately provided on the left and right sides of the movable mold 20 so that two circulation lines 30 are provided for each mold So that the temperature can be individually controlled.

Of course, according to the embodiment of the present invention, a plurality of circulation lines 30 may be formed instead of a plurality of molds for each of the molds, so that various circulation lines are divided into several parts of a single mold.

The circulation line 30 is a pipeline that is installed in the stationary mold 10 and the movable mold 20 to circulate the heating medium, as described above. In this circulation line 30, an interverter pump 31 is provided to circulate the heating medium and to control the flow rate of the circulating heating medium.

The circulation line 30 has a first line 41, a second line 42, and a third line 43 formed therein.

A heater 32 is installed in the first line 41 to allow the first line 41 of the circulation line 30 to be heated when the heating medium moves.

The second line 42 bypasses the first line 41 provided with the heater 32 and allows the heating medium to flow without heating the heating medium without passing through the first line 41. [

The third line 43 is a line connected to a chiller 50. A part of the heating medium flows into the chiller 50 and a heating medium cooled in the chiller 50 is supplied to the circulation line 30 And the cooled heating medium of the chiller 50 is mixed with the circulating heating medium at a constant temperature to be mixed. For example, when the heater 32 is turned on at a predetermined temperature, the temperature of the circulating heat medium is continuously increased. In the case of the third line 43, , It is used in the case where it is maintained at the preset temperature allowable range, or when the injection process is completed and the mold has to be cooled.

That is, when the heater 32 is driven, the cooling water (cooled heat medium) flows in through the third line 43 (simultaneous operation of the second and third lines 42 and 43) or the heater 32 is stopped (The second line 42 is OFF, and the third line 43 is operated only) through the third line 43 in a state where the third line 43 is in a state of being opened. In order to maintain the temperature of the mold at the pre-set temperature tolerance range, it is a part that can be selected in various ways in the control unit 80.

As a result, when the temperature of the heating medium is raised, the temperature is raised by using the first line 41, and when the temperature is higher than the predetermined temperature tolerance range of the circulating mold, the third line 43 is used And the heater 32 and the chiller 50 are heated by using the second line 42 when the temperature of the mold is maintained within the preset temperature tolerance range by using the first and third lines 41 and 43. [ So that the heat medium circulates without using the heat medium. This control is performed for each of the first, second and third lines L1, L2 and L3 of the first, second and third lines L1, L2 and L3 in the circulation line 30 via a separate control unit 80 The flow to one or more of the first, second, and third lines L1, L2, and L3 of the heating medium is selected through ON / OFF of a plurality of installed control valves (solenoid valves) Quenching operation, and the quenching operation.

For example, in the present invention, the first control valve V1 (three-way valve) is provided at the branch points of the first and second lines in the circulation line 30, The second control valve V2 is provided in the second line 42 so that the ON / OFF of the second line 42 can be controlled And the third line 43 is also provided with a third control valve V3 so that ON / OFF of the third line 43 can be controlled.

The main temperature sensors 61 and 62 are respectively installed in the fixed mold 10 and the movable mold 20 described above and measure the temperature to check whether each of the molds is maintained in the preset temperature tolerance range.

The measured temperature is transmitted to the control unit 80. The control unit 80 compares the measured temperature with the predetermined temperature of each mold and then outputs a single or a plurality of circulation lines 30 installed in each mold or each mold. The first, second and third lines (L1, L2, L3) are selected and opened and closed while controlling a plurality of control valves ON / OFF after determining which mode (heating, cooling, .

The inlet and outlet temperature sensors 71 and 72 are installed at the inlet and outlet of each of the circulation lines 30 installed in the stationary mold 10 and the movable mold 20. The inlet and outlet temperature sensors 71 and 72 are provided with a heating medium inlet and outlet temperature difference )).

In the present invention, the above-described mold is composed of the stationary mold 10 and the movable mold 20, and each of these molds may have the same preset temperature tolerance range. However, the stationary mold 10 and the movable mold 20 20 may have different preset temperature tolerances.

Accordingly, in the present invention, the amount of heat of the stationary mold 10 (the temperature of the stationary mold 10 when the stationary mold 10 has a pre-set temperature tolerance range allowing plastic injection) And the amount of heat of the movable mold 20 (the allowable range of the amount of heat when the movable mold 20 has a preset temperature tolerance range for allowing the movable mold 20 to perform plastic injection) The temperature difference between the front and rear ends of the heating medium flowing into the mold 10 and the movable mold 20 is controlled.

The formula for calculating the calorie is as follows as well known.

(Where Q is the amount of heat required for each mold to have a preset temperature for injection, C is the specific heat (heat required to raise the mold by 1 ° C), M is the mass (heat transfer amount) In other words, it adjusts the flow rate of the heating medium with the inverter pump while comparing the inflow and outflow temperature difference of the heating medium in accordance with the heat quantity specified in advance for each of a plurality of molds so that the heat quantity is corresponding to the specified heat quantity.

The measured heat quantity M 'of each mold is compared with a preset heat quantity (a heat quantity tolerance range M for allowing each mold to have a preset temperature for injection), and the inverter pump 31 (Step S10). Thereafter, the temperature measurement value? T 'of the mold is compared with the preset temperature difference? T, and the flow rate of the heat medium is adjusted through the inverter pump The preset heating calorie permissible range of the fixed mold 10 and the movable mold 20 is maintained at all times by controlling the flow rate of the heating medium through the valve 31 so as not to cause defects in the injection product .

If the measured calorie amount is higher than the preset calorie permissible range (step S11) or the measured inflow and outflow temperature difference is lower than the preset temperature difference allowable range (step S21), the flow rate circulated through the inverter pump 31 is decreased When the measured calorie amount is lower than the preset calorific value allowable range in step S12 and the measured inflow / outflow temperature difference is higher than the preset temperature difference allowable range in step S22, the flow rate circulated through the inverter pump 31 is increased, So that the predetermined calorific value of each of the above-described molds is within the preset calorific value allowable range. (If the flow rate of the incoming heat medium is small while the temperature of the mold is high, the temperature difference between the inlet and outlet of the heat medium passing through the mold is larger than the case where the flow rate of the incoming heat medium is large. In order to increase the flow rate of the heat medium,

In addition, in the present invention, there is provided an automatic bypass function for circulating the heat medium in the circulation line 30 without transferring the heat medium to the respective molds when the discharge pressure abnormality (valve locking phenomenon) of the inverter pump 31 occurs, And a fourth control valve (V4) is provided in a connection line connecting the inlet and outlet sides of the first control valve (30).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various changes and modifications may be made without departing from the scope of the appended claims.

10: stationary mold 20: movable mold
30: circulation line 31: inverter pump
32: heater 41: first line
42: second line 43: third line
50: Chiller 61, 62: Main temperature sensor
71, 72: Inlet / outlet temperature sensor 80:
V1: first control valve V2: second control valve
V3: third control valve V4: fourth control valve

Claims (4)

A stationary mold 10 and a movable mold 20 for plastic resin injection;
A circulation line (30) installed in each of the stationary mold (10) and the movable mold (20) and circulating the heating medium;
An inverter pump (31) installed in the circulation line (30) for transferring the heating medium;
A first line 41 in which a first control valve V1 is installed in the circulation line 30 and a heater 32 is installed to heat the heating medium;
A second line (42) in which a second control valve (V2) is installed in the circulation line (30) and circulates the heat medium through the heater (32);
A third control valve V3 is installed in the circulation line 30 and is connected to the chiller 50 so that the cooled heat medium circulated through the chiller 50 is mixed with the circulating heat medium, Line 43;
Main temperature sensors (61, 62) for measuring temperatures of the stationary mold (10) and the movable mold (20);
Outlet temperature sensors 71 and 72 respectively installed at the inflow and outflow ports of the circulation lines 30 provided in the stationary mold 10 and the movable mold 20 for measuring a temperature difference between the inflow and outflow of the heating medium; Lt; / RTI >
The fixed mold 10 and the movable mold 20 are controlled by the control unit 80 to control the inverter pump 31 for controlling the flow rate and a plurality of The first, second, and third lines L1, L2, and L3 are automatically selected through control of the control valves V1, V2, V3, and V4 to operate in any one of heating, cooling,
When the measured calorie amount of each of the dies is compared with the preset calorie amount and the measured calorie amount is different from the preset calorie amount, the flow amount of the heating medium is increased or decreased through the inverter pump 31, A step (S10) of controlling the heat medium flow rate until the allowable range is reached;
If the measured calorie of each mold reaches the preset calorie tolerance range in step S10,
Output temperature difference between the respective molds is compared with the preset temperature difference through the above-mentioned inflow and outflow temperature sensors (71, 72)
1) When the measured inflow / outflow temperature difference is larger than the preset temperature difference, the flow rate of the heating medium is increased and controlled through the inverter pump 31, 42 to circulate the heating medium without using the heater 32 and the chiller 50 to control the heating medium flow rate,
2) When the measured inflow / outflow temperature difference is smaller than the preset temperature difference, the flow rate of the heating medium is reduced and controlled through the inverter pump 31, The heat medium is circulated without using the heater 32 and the chiller 50 by using the heater 42 to adjust the flow rate and temperature difference of the heat medium,
(S20) that the mold injection is completed when the measured calorific value of each of the molds falls within the allowable range of the preset calorie amount and the measured inflow and outflow temperature difference also falls within the allowable range of the predetermined temperature difference
The predetermined heat quantity and the preset temperature difference of each of the stationary mold 10 and the movable mold 20 are kept within the permissible range at the same time so that defects of the injection product are not generated. In the plastic resin injection molding, A method for controlling the amount of heat by a pump.
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