CN112873773B

CN112873773B - Automatic control system of injection molding machine

Info

Publication number: CN112873773B
Application number: CN202110036933.6A
Authority: CN
Inventors: 颜国球
Original assignee: Guangzhou Shengshuo Technology Co ltd
Current assignee: Guangzhou Shengshuo Technology Co ltd
Priority date: 2021-01-12
Filing date: 2021-01-12
Publication date: 2021-11-12
Anticipated expiration: 2041-01-12
Also published as: CN112873773A

Abstract

The invention relates to an automatic control system of an injection molding machine. The injection molding device comprises an injection molding box and an equipment box, wherein the injection molding box is provided with an upper mold, a lower mold, an electric push rod and a heating box and is used for injection molding; the equipment box is provided with a PLC terminal, a controller and a current sensor and is used for controlling the temperature of the injection molding machine in real time. According to the invention, the temperature in the injection molding machine is monitored in real time and adjusted according to the real-time monitoring result, so that the problem of difficult injection molding caused by overhigh or overlow temperature is effectively avoided, and the injection molding efficiency is greatly improved.

Description

Automatic control system of injection molding machine

Technical Field

The invention relates to the technical field of injection molding machine control, in particular to an automatic control system of an injection molding machine.

Background

An injection molding machine is also known as an injection molding machine or an injection machine. It is a main forming equipment for making various shaped plastic products from thermoplastic plastics or thermosetting plastics by using plastic forming mould. The device is divided into a vertical type, a horizontal type and a full-electric type. The injection molding machine can heat plastic, apply high pressure to the molten plastic, and inject it to fill the mold, and can be divided into vertical, horizontal and vertical-horizontal compound types according to the arrangement of the injection device and the mold locking device.

Most of injection molding machines on the existing market lack a temperature control system, are difficult to control the temperature in the injection molding machine, and the temperature in the injection molding machine is too low to cause the product in the mould to solidify in advance easily, and the temperature is too high to cause injection molding to be difficult to form easily, so that the production efficiency of the mould is reduced.

Disclosure of Invention

Therefore, the invention provides an automatic control system of an injection molding machine. The injection molding machine is used for solving the problem that the injection molding machine in the prior art is difficult to mold due to overhigh or overlow temperature, so that the production efficiency of the injection molding machine is low.

In order to achieve the above object, the present invention provides an automatic control system for an injection molding machine, comprising:

the injection molding box is internally provided with a mold and a heating resistor, and the heating resistor is arranged on the bottom surface inside the injection molding box body;

the equipment box is internally provided with a PLC terminal for monitoring the temperature in the die in real time, a controller for receiving an instruction of the PLC terminal and a current sensor for detecting the current in the heating resistor; the current sensor is respectively connected with the PLC terminal and the controller, the controller is also connected with the heating resistor, and the mold is also provided with a temperature sensor;

the PLC terminal detects the temperature in the mold in real time by using the temperature sensor, sends a corresponding instruction to the controller according to the temperature measured by the temperature sensor, and adjusts the temperature in the mold of the injection molding machine according to the instruction sent by the PLC terminal;

the PLC terminal is provided with a preset material type matrix P0 and a preset injection molding temperature range matrix Ta0, the preset material type matrix P0 is set with P0(P1, P2, P3 and P4), wherein P1 is a first preset material type, P2 is a second preset material type, P3 is a third preset material type, P4 is a fourth preset material type, the preset injection molding temperature range matrix Ta0 is set with Ta0(Ta 1-Tb 1, Ta 2-Tb 2, Ta 3-Tb 3 and Ta 4-Tb 4), wherein Ta 1-Tb 1 is a first preset injection molding temperature range, Ta1 < 1, Ta 2-Tb 2 are second preset injection molding temperature ranges, Ta2 < 2, Ta 3-Tb 3 is a third preset injection molding temperature range, Ta3 < 3, Ta4 < Tb4 is a fourth injection molding temperature range which is not overlapped with each other injection molding temperature ranges;

the PLC terminal selects corresponding injection molding temperature according to the material type to heat the mold,

when the material is P1, the PLC terminal controls the injection molding temperature to be Ta 1-Tb 1, wherein Ta1 is the preset lowest injection molding temperature, and Tb1 is the highest injection molding temperature;

when the material is P2, the PLC terminal controls the injection molding temperature to be Ta 2-Tb 2, wherein Ta2 is the preset lowest injection molding temperature, and Tb2 is the highest injection molding temperature;

when the material is P3, the PLC terminal controls the injection molding temperature to be Ta 3-Tb 3, wherein Ta3 is the preset lowest injection molding temperature, and Tb3 is the highest injection molding temperature;

when the material is P4, PLC terminal control will the temperature of moulding plastics sets up to Ta4 ~ Tb4, and wherein Ta4 is for predetermineeing the minimum temperature of moulding plastics, and Tb4 is the highest temperature of moulding plastics.

Further, the PLC terminal is further provided with a preset material mass matrix M0 and a preset temperature lower correction coefficient matrix Ka0, and for the material mass matrix M0, M0(M1, M2, M3, M4) is set, where M1 is the first preset material mass, M2 is the second preset material mass, M3 is the third preset material mass, M4 is the fourth preset material mass, and the preset material masses increase in sequence; setting Ka0(Ka1, Ka2, Ka3 and Ka4) for the preset temperature lower correction coefficient matrix Ka0, wherein Ka1 is a first preset temperature lower correction coefficient, Ka2 is a second preset temperature lower correction coefficient, Ka3 is a third preset temperature lower correction coefficient, Ka4 is a fourth preset temperature lower correction coefficient, and 1 & lt Ka1 & lt Ka2 & lt Ka3 & lt Ka4 & lt 2;

when the PLC terminal sets the injection molding temperature range to Tai-Tbi, setting i to 1, 2, 3, 4, after the controller controls the heating resistor to heat the mold for D1 time, if the temperature sensor measures that the actual temperature T of the mold is less than Tai, the PLC terminal obtains the mass M of the material added into the mold, selects a corresponding temperature lower correction coefficient Ka according to the mass M of the material to correct the injection molding temperature so as to enable the actual temperature T of the mold to reach the preset injection molding temperature range Tai-Tbi,

when M1 is not less than M < M2, the PLC terminal selects Ka1 to correct the injection molding temperature;

when M2 is not less than M < M3, the PLC terminal selects Ka2 to correct the injection molding temperature;

when M3 is not less than M < M4, the PLC terminal selects Ka3 to correct the injection molding temperature;

when M is larger than or equal to M4, the PLC terminal selects Ka4 to correct the injection molding temperature;

when the PLC terminal selects a preset correction coefficient Kai with a lower temperature to correct the actual temperature, setting i to be 1, 2, 3 and 4, setting the corrected temperature to be Taj, and setting the Taj to be T multiplied by Kai;

the PLC terminal is further provided with a preset temperature high correction coefficient matrix Kb0, and Kb0(Kb1, Kb2, Kb3 and Kb4) is set for the preset temperature high correction coefficient matrix Kb0, wherein Kb1 is a first preset temperature high correction coefficient, Kb2 is a second preset temperature high correction coefficient, Kb3 is a third preset temperature high correction coefficient, Kb4 is a fourth preset temperature high correction coefficient, Kb1 is greater than 0.5, Kb2 is greater than Kb3, and Kb4 is less than 1;

when the material type in the injection molding machine is Pi, setting i to be 1, 2, 3 and 4, setting the injection molding temperature range to be Tai to Tbi by the PLC terminal, controlling a heating resistor to heat the mold for D1 time by the controller, detecting the actual temperature T of the mold to be more than Tbi by the temperature sensor, acquiring the mass M of the material in the mold by the PLC terminal, selecting a corresponding higher temperature correction coefficient Kb according to the mass M of the material to correct the injection molding temperature so as to enable the actual temperature T of the mold to reach the preset injection molding temperature range Tai to Tbi,

when M1 is not less than M < M2, the PLC terminal selects Kb1 to correct the injection molding temperature;

when M2 is not less than M < M3, the PLC terminal selects Kb2 to correct the injection molding temperature;

when M3 is not less than M < M4, the PLC terminal selects Kb3 to correct the injection molding temperature;

when M is larger than or equal to M4, the PLC terminal selects Kb4 to correct the injection molding temperature;

when the PLC terminal selects a preset temperature-raising correction coefficient Kbi to correct the actual temperature, i is set to 1, 2, 3, and 4, and the corrected temperature is Tbj, and Tbj is set to T × Kbi.

Further, the PLC terminal is further provided with a preset first current matrix Ia0 and a preset temperature lower difference matrix Ca0, and for the preset first current matrix Ia0, Ia0(Ia1, Ia2, Ia3, Ia4) is set, where Ia1 is a first preset first current, Ia2 is a second preset first current, Ia3 is a third preset first current, and Ia4 is a fourth preset first current, and the preset first currents increase in sequence; for the preset temperature lower difference matrix Ca0, setting Ca0(Ca1, Ca2, Ca3, Ca4), where Ca1 is a first preset temperature lower difference, Ca2 is a second preset temperature lower difference, Ca3 is a third preset temperature lower difference, and Ca4 is a fourth preset temperature lower difference, and the preset temperature lower differences increase in sequence;

after the controller controls the heating resistor to heat the mold for D2 time, the temperature sensor detects that the corrected temperature Taj of the mold is less than Tai, the PLC terminal calculates the difference value Ca between the actual temperature and the lowest injection molding temperature, the set Ca is Tai-Taj, after the calculation is finished, the PLC terminal adjusts the current I leading to the heating resistor according to the temperature difference Ca,

when Ca1 is less than or equal to Ca < Ca2, the PLC terminal regulates the current led to the heating resistor to Ia 1;

when Ca2 is less than or equal to Ca < Ca3, the PLC terminal regulates the current led to the heating resistor to Ia 2;

when Ca3 is less than or equal to Ca < Ca4, the PLC terminal regulates the current led to the heating resistor to Ia 3;

when Ca is larger than or equal to Ca4, the PLC terminal adjusts the current led to the heating resistor to Ia 4.

Further, the PLC terminal is further provided with a preset second current matrix Ib0 and a preset temperature deviation value matrix Cb0, and for the preset second current matrix Ib0, Ib0(Ib1, Ib2, Ib3, Ib4) is set, where Ib1 is a first preset second current, Ib2 is a second preset second current, Ib3 is a third preset second current, and Ib4 is a fourth preset second current, and the preset second currents decrease in sequence; setting Cb0(Cb1, Cb2, Cb3 and Cb4) for the preset temperature rise difference value matrix Cb0, wherein Cb1 is a first preset temperature rise difference value, Cb2 is a second preset temperature rise difference value, Cb3 is a third preset temperature rise difference value, Cb4 is a fourth preset temperature rise difference value, and the preset temperature rise difference values are increased in sequence;

after the controller controls the heating resistor to heat the mold for D2 time, the temperature sensor detects that the correction temperature Tbj of the mold is more than Tbi, then the PLC terminal calculates the difference Cb between the actual temperature and the highest injection molding temperature, the Cb is set to be Tbi-Tbj, after the calculation is finished, the PLC terminal controls the current I leading to the heating resistor according to the temperature higher difference Cb,

when Cb1 is less than or equal to Cb < Cb2, the PLC terminal adjusts the current led to the heating resistor to Ib 1;

when Cb2 is less than or equal to Cb < Cb3, the PLC terminal adjusts the current led to the heating resistor to Ib 2;

when Cb3 is less than or equal to Cb < Cb4, the PLC terminal adjusts the current led to the heating resistor to Ib 3;

when Cb is larger than or equal to Cb4, the PLC terminal adjusts the current led to the heating resistor to Ib 4.

Further, the PLC terminal is further provided with a preset maximum current value Imax, a preset first current difference matrix Δ a0, and a preset temperature-raising resistance wire length adjustment coefficient matrix Xa0, and for the preset first current difference matrix Δ a0, Δ a0(Δ a1, Δ a2, Δ a3, Δ a4) is set, where Δ a1 is a first preset first current difference value, Δ a2 is a second preset first current difference value, Δ a3 is a third preset first current difference value, Δ a4 is a fourth preset first current difference value, and the preset first current difference values are sequentially increased; for the preset heating resistance wire length adjusting coefficient matrixes Xa0 and Xa0(Xa1, Xa2, Xa3 and Xa4), wherein Xa1 is a first preset heating resistance wire length adjusting coefficient, Xa2 is a second preset heating resistance wire length adjusting coefficient, Xa3 is a third preset heating resistance wire length adjusting coefficient, Xa4 is a fourth preset heating resistance wire length adjusting coefficient, and Xa1, Xa2, Xa3 and Xa4 are set to be more than 1 and Xa1 and less than 2;

when the PLC terminal sets a first current to the heating resistor to Iai, the first current Iai is larger than Imax, and the temperature sensor detects that the actual temperature T of the die is smaller than Tai, setting i to be 1, 2, 3 and 4, and acquiring a difference value delta a between the first current Iai and the preset maximum current Imax by the PLC terminal;

when the PLC terminal sets the initial resistance wire length of the heating resistor as Lai, the PLC terminal selects a corresponding resistance wire length adjusting coefficient Xa according to the actual current difference Delta a to adjust the resistance wire length La of the heating resistor,

when the delta a is not less than delta a1 and is less than delta a2, Xa1 is selected by the PLC terminal to adjust the length of the resistance wire of the heating resistor;

when the delta a is not less than delta a2 and is less than delta a3, Xa2 is selected by the PLC terminal to adjust the length of the resistance wire of the heating resistor;

when the delta a is not less than delta a3 and is less than delta a4, Xa3 is selected by the PLC terminal to adjust the length of the resistance wire of the heating resistor;

when the delta a is larger than or equal to the delta a4, the PLC terminal selects Xa4 to adjust the length of the resistance wire of the heating resistor;

when the PLC terminal selects Xai to adjust the heating temperature of the die, setting i to be 1, 2, 3 and 4, setting the length of the adjusted resistance wire to be Laj, and setting Laj to be Lai multiplied by Xai.

Further, the PLC terminal is further provided with a preset minimum current value Imin, a preset second current difference matrix Δ b0, and a preset temperature reduction resistance wire length adjustment coefficient matrix Xb0, and for the preset second current difference matrix Δ b0, Δ b0(Δ b1, Δ b2, Δ b3, Δ b4) is set, where Δ b1 is a first preset second current difference value, Δ b2 is a second preset second current difference value, Δ b3 is a third preset second current difference value, and Δ b4 is a fourth preset second current difference value, and the preset second current difference values are sequentially increased; for the preset temperature-reducing resistance wire length adjustment coefficient matrixes Xa0 and Xa0(Xa1, Xa2, Xa3 and Xa4), wherein Xa1 is the length adjustment coefficient of the first preset temperature-reducing resistance wire, Xa2 is the length adjustment coefficient of the second preset temperature-reducing resistance wire, Xa3 is the length adjustment coefficient of the third preset temperature-reducing resistance wire, Xa4 is the length adjustment coefficient of the fourth preset temperature-reducing resistance wire, and Xa1, Xa2, Xa3, Xa4 and 1 are set to be more than 0.5 and Xa1 and more than Xa 3552 and Xa 4;

when the PLC terminal sets a second current to the heating resistor to be Ibi, the second current Ib is less than Imin and the temperature sensor detects that the actual temperature T of the die is more than Tbi, setting i to be 1, 2, 3 and 4, and then obtaining a difference value delta b between the second current Ibi and the preset minimum current Imin by the PLC terminal;

when the PLC terminal sets the initial resistance wire length of the heating resistor to Lbi, the PLC terminal selects a corresponding resistance wire length adjustment coefficient Xb according to the actual current difference value delta b to adjust the resistance wire length Lb of the heating resistor,

when the delta b1 is not less than the delta b which is less than the delta b2, the PLC terminal selects Xb1 to adjust the length of the resistance wire of the heating resistor;

when the delta b2 is not less than the delta b which is less than the delta b3, the PLC terminal selects Xb2 to adjust the length of the resistance wire of the heating resistor;

when the delta b3 is not less than the delta b which is less than the delta b4, the PLC terminal selects Xb3 to adjust the length of the resistance wire of the heating resistor;

when the delta b is larger than or equal to the delta b4, the PLC terminal selects Xb4 to adjust the length of the resistance wire of the heating resistor;

when the PLC terminal selects Xbi to adjust the heating temperature of the die, setting i to be 1, 2, 3 and 4, setting the length of the adjusted resistance wire to be Lbj, and setting Lbj to be Lbi × Xbi.

Further, the PLC terminal is further provided with a preset heating time matrix ta0, and for the preset heating time matrix ta0, ta0(ta1, ta2, ta3, ta4) is set, where ta1 is a first preset heating time, ta2 is a second preset heating time, ta3 is a third preset heating time, and ta4 is a fourth preset heating time, and the preset heating times are sequentially increased;

when the resistance wire of the heating resistor is adjusted to the maximum value by the PLC terminal and T is less than Tai, the PLC terminal sends an instruction for increasing the heating time of the heating resistor to the controller according to the material type,

when the material is P1, the PLC terminal increases the heating time to be ta 1;

when the material is P2, the PLC terminal increases the heating time to be ta 2;

when the material is P3, the PLC terminal increases the heating time to be ta 3;

when the material is P4, the PLC terminal increases the heating time period to be ta 4.

Further, the automatic control system of the injection molding machine comprises a motor arranged in the equipment box and a fan connected with the motor, the PLC terminal is further provided with a preset rotating speed matrix V0, and V0(V1, V2, V3 and V4) is set, wherein V1 is a first preset rotating speed, V2 is a second preset rotating speed, V3 is a third preset rotating speed, and V4 is a fourth preset rotating speed, and the preset rotating speeds are increased in sequence; when the temperature sensor detects that the temperature Tb in the mold is larger than Tbi, the PLC terminal calculates a temperature higher difference Cb, the Cb is set to Tb-Tbi, after calculation is finished, the PLC terminal determines the rotating speed of the fan according to the temperature higher difference to dissipate heat of the equipment box,

when Cb1 is not less than Cb < Cb2, the PLC terminal sets the rotating speed of the fan to be V1;

when Cb2 is not less than Cb < Cb3, the PLC terminal sets the rotating speed of the fan to be V2;

when Cb3 is not less than Cb < Cb4, the PLC terminal sets the rotating speed of the fan to be V3;

and when Cb is larger than or equal to Cb4, the PLC terminal sets the rotating speed of the fan to be V4.

Further, the PLC terminal is further provided with a preset resistance wire length matrix Lb0 and a preset rotation speed regulation coefficient matrix E0, for the preset resistance wire length matrix Lb0, Lb0(Lb1, Lb2, Lb3 and Lb4) is set, wherein Lb1 is the length of a first preset resistance wire, Lb2 is the length of a second preset resistance wire, Lb3 is the length of a third preset resistance wire, Lb4 is the length of a fourth preset resistance wire, and the lengths of the preset resistance wires are increased in sequence; setting E0(E1, E2, E3 and E4) for the preset rotating speed adjusting coefficient matrix E0, wherein E1 is a first preset rotating speed adjusting coefficient, E2 is a second preset rotating speed adjusting coefficient, E3 is a third preset rotating speed adjusting coefficient, E4 is a fourth preset rotating speed adjusting coefficient, and E1 is more than 1 and E2 is more than E3 and more than E4 is less than 2;

when the temperature sensor detects that the temperature of the die is too high and the PLC terminal sets the rotating speed of the fan to Vi, the PLC terminal adjusts the rotating speed of the fan according to the length Lb of the resistance wire,

when Lb1 is not less than Lb < Lb2, the PLC terminal selects E1 to adjust the rotating speed of the fan;

when Lb2 is not less than Lb < Lb3, the PLC terminal selects E2 to adjust the rotating speed of the fan;

when Lb3 is not less than Lb < Lb4, the PLC terminal selects E3 to adjust the rotating speed of the fan;

when Lb is larger than or equal to Lb4, the PLC terminal selects E4 to adjust the rotating speed of the fan;

when the PLC terminal selects Ei to adjust the rotating speed of the fan, setting i to be 1, 2, 3 and 4, setting the adjusted rotating speed of the fan to be Vj, and setting Vj to be Vi multiplied by Ei.

Further, injection molding machine automatic control system still includes alarm and alarm lamp, works as temperature sensor detects the temperature of mould with the difference of the highest temperature of moulding plastics surpasss the fourth and predetermines the high difference of temperature or works as current sensor detects when the change volume of electric current is unusual, the PLC terminal to the controller sends the instruction of starting alarm lamp and alarm.

Compared with the prior art, the injection molding machine has the advantages that through setting the material type and the temperature range value corresponding to the material type in the PLC terminal, the injection molding machine can select different temperature ranges for heating the mold aiming at different materials, so that the injection molding machine can flexibly adjust the heating temperature, the injection molding efficiency is ensured, and meanwhile, the production efficiency of the system is effectively improved.

Furthermore, the PLC terminal is also provided with a preset material quality matrix M0 and a preset temperature lower correction coefficient matrix Ka0, when the heating resistor heats the die, the temperature sensor detects the temperature of the die in real time and transmits the temperature to the PLC terminal, the PLC terminal compares the real-time temperature T with the preset temperature Tai and analyzes, if T is less than Tai, the PLC terminal judges that the temperature of the die is too low and needs to be corrected, the PLC terminal corrects the heating temperature by acquiring the mass of the material in the die and the correction coefficients corresponding to the mass of different materials and the lower temperature, so that the heating temperature can reach a preset temperature range value, the control of the PLC terminal on the heating temperature is improved, the production efficiency of the system is further improved while the injection molding efficiency is further ensured.

Further, the PLC terminal is also provided with a preset temperature over-high correction coefficient matrix Kb0, the temperature sensor detects the temperature of the mold in real time and transmits the temperature to the PLC terminal, the PLC terminal compares and analyzes the real-time temperature T and the preset temperature Tai, if T is greater than Tbi, the PLC terminal judges that the heating temperature of the mold is too high and needs to be corrected, and the PLC terminal corrects the heating temperature by acquiring the material quality in the mold and the temperature over-high correction coefficients corresponding to different material qualities, so that the heating temperature can be reduced to the preset temperature range value, the control of the PLC terminal on the heating temperature is further improved, the injection molding efficiency is further guaranteed, and the production efficiency of the system is further improved.

Further, the PLC terminal is provided with a preset first current matrix Ia0 and a preset temperature lower difference matrix Ca0, the heating resistor heats the mold, the temperature sensor detects the actual temperature T in the mold in real time, when T is smaller than Tai, the PLC terminal obtains the value of the actual temperature and compares the value of the actual temperature with the minimum injection molding temperature of the preset temperature range value to calculate a temperature difference value, the current to the heating resistor is increased through the temperature difference value adjustment to further adjust the injection molding temperature, the control of the PLC terminal on the injection molding temperature is further improved, the injection molding efficiency is further guaranteed, and meanwhile the production efficiency of the system is further improved.

Further, the PLC terminal is provided with a preset second current matrix Ib0 and a preset temperature higher difference matrix Ca0, when the heating resistor heats the mold, the temperature sensor detects the actual temperature T of the mold in real time, when T is larger than Tbi, the PLC terminal obtains the value of the actual temperature and compares the value of the actual temperature with the maximum injection molding temperature of the preset temperature range value to calculate a temperature difference value, the actual current to the heating resistor is reduced through the temperature difference value adjustment to further adjust the injection molding temperature, the control of the PLC terminal on the injection molding temperature is further improved, the injection molding efficiency is further guaranteed, and meanwhile the production efficiency of the system is further improved.

The PLC terminal is further provided with a preset maximum current value Imax, a preset first current difference matrix delta a0 and a preset heating resistance wire length adjusting coefficient matrix Xa0, when the heating resistor heats the mold, the PLC terminal adjusts the current, T is less than Tai, the PLC terminal obtains the current value detected by the current sensor in real time, the real-time current value I is compared with the adjusted current value Iai to calculate the difference, and the PLC terminal adjusts the length of the resistance wire according to the difference and the preset heating resistance wire length adjusting coefficient to increase the injection molding temperature and further improve the control of the injection molding temperature.

The PLC terminal is further provided with a preset minimum current value Imin, a preset second current difference value matrix delta b0 and a preset heating resistance wire length adjusting coefficient matrix Xb0, when the heating resistor heats the mold, the PLC terminal adjusts the current, T is less than Tbi, the PLC terminal obtains the current value detected by the current sensor in real time, the real-time current value I is compared with the adjusted current value Iai to calculate the difference value, and the PLC terminal adjusts the length of the resistance wire according to the difference value and the preset cooling resistance wire length adjusting coefficient to reduce the injection molding temperature and further improve the control of the injection molding temperature, so that the injection molding efficiency is further guaranteed, and the production efficiency of the system is further improved.

Further, the PLC terminal is further provided with a preset heating time matrix T0, when the heating resistor heats the mold and the PLC terminal adjusts the length of the resistance wire to the longest length through the controller, the temperature sensor detects that the actual temperature T of the mold is smaller than the preset minimum injection molding temperature in real time, the PLC terminal increases the heating time through the controller to increase the injection molding temperature, the control of the injection molding temperature is further improved, the injection molding efficiency is further guaranteed, and meanwhile, the production efficiency of the system is further improved.

Furthermore, the PLC terminal is also provided with a preset rotating speed matrix V0, when the injection molding machine performs injection molding, the PLC terminal controls and starts the fan through the controller and enables the fan to radiate the equipment box at a certain rotating speed, so that the protection of the parts of the injection molding machine is improved, the injection molding efficiency is further ensured, and the production efficiency of the system is further improved.

Furthermore, the PLC terminal is further provided with a preset resistance wire length matrix Lb0 and a preset rotating speed adjusting coefficient matrix E0, when the injection molding temperature is too high, the PLC terminal acquires the adjusting length of the resistance wire in real time and controls the rotating speed of the fan to be adjusted in real time through a controller according to the adjusting length of the resistance wire, so that the protection of parts of the injection molding machine is further improved, the injection molding efficiency is further guaranteed, and the production efficiency of the system is further improved.

The injection molding machine is further provided with an alarm and an alarm lamp, when the temperature sensor detects that the difference value between the temperature of the mold and the highest injection molding temperature exceeds the preset highest temperature deviation value, the PLC terminal sends an instruction for starting the alarm lamp and the alarm to the controller, and when the current sensor detects that the current variation is abnormal, the PLC terminal sends an instruction for starting the alarm lamp and the alarm to the controller, and after the central controller receives the instruction, the alarm lamp and the alarm are started to inform a user of checking, so that the injection molding temperature is further controlled, the injection molding efficiency is further guaranteed, and meanwhile, the production efficiency of the injection molding system is further improved.

Drawings

FIG. 1 is a schematic diagram of the external structure of the automatic control system of the injection molding machine according to the present invention;

FIG. 2 is a cross-sectional view of the automatic control system of the injection molding machine according to the present invention.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.

It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Fig. 1 to fig. 2 are schematic diagrams showing an external structure of the automatic control system of an injection molding machine according to the present invention and cross-sectional views of the automatic control system of an injection molding machine according to the present invention. The automatic control system of the injection molding machine comprises an injection molding box 3 and an equipment box 13, wherein an upper mold 6, a lower mold 7, an electric push rod 4, an injection molding pipe 11 and a heating box 8 are arranged in the injection molding box 3, the heating box is arranged on the bottom surface inside a box body of the injection molding box, a heating resistor is arranged in the heating box, and the end surface of the upper mold, far away from the lower mold, is connected with the electric push rod; the equipment box is provided with a PLC terminal 14, a controller 15 and a current sensor 12, the PLC terminal 14 is used for monitoring the temperature of the injection molding machine die in real time, and the controller 15 is used for receiving instructions of the PLC terminal and controlling the heating box 8 and the electric push rod 7.

Specifically, the current sensor 16 is respectively connected with the PLC terminal 14 and the controller 15, the controller 15 is further connected with the electric push rod 4 and the heating box 8, the side wall of the injection molding box 3 is further provided with an injection molding pipe 11, the injection molding pipe 11 penetrates through the injection molding box 3 and penetrates through the side wall of the lower mold 10 close to the injection molding box 3, the side wall of the lower mold 10 far away from the injection molding pipe 11 is further provided with a temperature sensor 12, and the temperature sensor 12 and the PLC terminal 14 are further provided; when the injection molding machine is operated, the PLC terminal 14 monitors the temperature detected by the temperature sensor 12 in real time and sends an instruction to the controller 15 according to the real-time temperature, and the controller adjusts the temperature in the mold of the injection molding machine according to the instruction of the PLC terminal 14.

With reference to fig. 1 to 2, the automatic control system of an injection molding machine according to the embodiment of the present invention further includes a bottom plate 1, support legs 2, an alarm 17, a warning light 18, a movable door 19, an observation window 20, a handle 21, an equipment box door 27, and a handle 28, wherein the equipment box 13 and the injection molding box 2 are disposed on the bottom plate 1; the bottom plate 1 is supported by four supporting legs 2, the movable door 19 is installed on the injection molding box 3, and the observation window 20 is arranged on the movable door 19 and used for observing the working state inside the injection molding machine; the movable door 19 is also provided with a handle 21 positioned on the right side of the observation window 20, so that the movable door 19 can be conveniently opened when the interior of the injection molding machine needs to be maintained; the alarm 17 is arranged on the side wall of one side of the injection molding box 3 and used for alarming and prompting a user when the temperature of the injection molding machine is too high; an equipment box door 27 is installed on the front side of the equipment box 13, and a handle 28 is installed on the equipment box door and used for checking and maintaining components in the equipment box 13 and setting various types of data for the PLC terminal.

Specifically, before the injection molding machine runs, various data are set in the PLC terminal by opening the equipment box door 27, and then the movable door is opened to inspect components in the injection molding box 3; when the injection molding machine is operated, the operation condition in the injection molding machine can be observed in real time through the observation window 20; when the temperature is too high or the current is unstable when the injection molding machine operates, the controller controls the alarm 17 to give an alarm and enables the warning lamp 18 to light up to remind a user.

Fig. 2 is a cross-sectional view of the automatic control system of the injection molding machine according to the present invention. According to the automatic control system of the injection molding machine, an upper mold and a heating resistor 9 are installed in an injection molding box 3, and the heating resistor 9 is arranged on the bottom surface inside a box body of the injection molding box 3; a PLC terminal 14 for monitoring the temperature of the mold in real time, a controller 15 for receiving an instruction of the PLC terminal 14 and a current sensor 16 for detecting the current of the injection molding machine are installed in the equipment box 13; the current sensor 16 is respectively connected with the PLC terminal 14 and the controller 15, the controller 15 is also connected with the heating resistor 9, and the mold is also provided with a temperature sensor 12.

Specifically, the PLC terminal 14 sends an instruction to the controller 15 according to the real-time monitoring temperature, and the controller 15 adjusts the temperature in the mold of the injection molding machine according to the instruction of the PLC terminal 14, so that the injection molding machine is automatically controlled, and the injection molding efficiency is improved.

As shown in fig. 2, a reinforcing plate 5, a supporting column 7 and a heating resistor 9 are further installed in the injection molding box, the reinforcing plate 5 is installed on two sides of the electric push rod 4 and used for fixing the electric push rod 4 on the upper end surface of the inner side of the injection molding box 3, the supporting column 7 is arranged on the lower end surface of the inner side of the injection molding box 3 and used for supporting the heating box 8, and the heating resistor 9 is arranged in the heating box 8; still install current sensor 16, backup pad 22, fixed column 23, motor 24, fan 25 and filter screen 26 in the equipment box, current sensor 16 installs on the inside up end of equipment box 13, current sensor 16 with the PLC terminal connection for real-time detection access to heating resistor 9's electric current, backup pad 22 is fixed the inside right side wall of equipment box 13, fixed column 23 is fixed the inside up end of equipment box 13, the one end that backup pad 22 keeps away from equipment box 13 with the fixed column 23 is kept away from the one end of equipment box is connected, motor 24 is installed on fixed column 23 right side, the one end that motor 24 kept away from fixed column 23 is installed fan 25, fan 25 right side equipment box wall is installed filter screen 26.

Specifically, when the injection molding machine is operated, the electric push rod 4 pushes the upper mold 10 to move downwards so as to clamp the upper mold 10 and the lower mold 11, and the heating resistor 9 heats the lower mold 11 for injection molding. Monitoring the temperature in the injection molding box 3 and the current detected by a current sensor 16 in real time through the PLC terminal 14 so as to keep the injection molding temperature within a certain range; the equipment box 13 is cooled by the fan 25.

Referring to fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal is provided with a preset material type matrix P0 and a preset injection molding temperature range matrix Ta0, and for the preset material type matrix P0, P0(P1, P2, P3, P4) is set, wherein P1 is a first preset material type, P2 is a second preset material type, P3 is a third preset material type, P4 is a fourth preset material type, Ta0(Ta 1-Tb 1, Ta 2-Tb 2, Ta 3-Tb 3, Ta 4-Tb 4) is set for the preset injection molding temperature range matrix Ta0, ta 1-Tb 1 are a first preset injection molding temperature range, Ta1 is less than Tb1, Ta 2-Tb 2 are a second preset injection molding temperature range, Ta2 is less than Tb2, Ta 3-Tb 3 are a third preset injection molding temperature range, Ta3 is less than Tb3, Ta 4-Tb 4 are a fourth preset injection molding temperature range, and the range values of the preset injection molding temperatures are not overlapped with each other;

specifically, the PLC terminal selects the corresponding injection molding temperature according to the material type to heat the mold,

It can be understood that, in the PLC terminal 14 according to the embodiment of the present invention, the preset material types and the preset injection molding temperature ranges are not limited to four types described in this embodiment, and may be any material types required for injection molding, and a user may input the data into the PLC terminal in a programming manner to control an injection molding machine to complete injection molding operation.

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal 14 further includes a preset material quality matrix M0 and a preset correction coefficient matrix Ka0 with a lower temperature, and for the material quality matrix M0, M0(M1, M2, M3, M4) is set, where M1 is the first preset material quality, M2 is the second preset material quality, M3 is the third preset material quality, and M4 is the fourth preset material quality, and the preset material qualities are sequentially increased; for the preset temperature lower correction coefficient matrix Ka0, Ka0(Ka1, Ka2, Ka3, Ka4) is set, where Ka1 is a first preset temperature lower correction coefficient, Ka2 is a second preset temperature lower correction coefficient, Ka3 is a third preset temperature lower correction coefficient, Ka4 is a fourth preset temperature lower correction coefficient, and 1 < Ka1 < Ka2 < Ka3 < Ka4 < 2.

Specifically, when the PLC terminal sets the injection temperature range to Tai-Tbi, i is set to 1, 2, 3, 4, after the controller controls the heating resistor to heat the mold for D1 time, if the temperature sensor measures that the actual temperature T of the mold is less than Tai, the PLC terminal obtains the mass M of the material added into the mold, selects a corresponding temperature lower correction coefficient Ka according to the mass M of the material to correct the injection temperature so that the actual temperature T of the mold reaches the preset injection temperature range Tai-Tbi,

when the PLC terminal 14 selects a preset correction coefficient Kai with a lower temperature to correct the actual temperature, setting i to 1, 2, 3, 4, and setting Taj to T × Kai;

specifically, when the PLC terminal sets the injection temperature range to Tai-Tbi, sets i to 1, 2, 3, 4, and the controller 15 controls the heating resistor to heat the mold for D1 time, the temperature sensor 12 detects that the actual temperature T of the mold is greater than Tbi, the PLC terminal 14 obtains the mass M of the material in the mold, selects a corresponding higher temperature correction coefficient Kb according to the mass M of the material to correct the injection temperature so that the actual temperature T of the mold reaches the preset injection temperature range Tai-Tbi,

when the PLC terminal 14 selects the preset temperature overshoot correction coefficient Kbi to correct the actual temperature, i is set to 1, 2, 3, and 4, the corrected temperature is Tbj, and Tbj is set to T × Kbi.

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal 14 further includes a preset first current matrix Ia0 and a preset temperature difference matrix Ca0, and for the preset first current matrix Ia0, Ia0(Ia1, Ia2, Ia3, and Ia4) are set, where Ia1 is a first preset first current, Ia2 is a second preset first current, Ia3 is a third preset first current, and Ia4 is a fourth preset first current, and the preset first currents are sequentially increased; for the preset temperature lower difference matrix Ca0, setting Ca0(Ca1, Ca2, Ca3, Ca4), where Ca1 is a first preset temperature lower difference, Ca2 is a second preset temperature lower difference, Ca3 is a third preset temperature lower difference, and Ca4 is a fourth preset temperature lower difference, and the preset temperature lower differences increase in sequence;

specifically, when the controller 15 controls the heating resistor to heat the mold for a time D2, and the temperature sensor 12 detects a corrected temperature Taj < Tai of the mold, the PLC terminal 14 calculates a difference value Ca between an actual temperature and a minimum injection temperature, sets Ca-Tai-Taj, and after the calculation is completed, the PLC terminal 14 adjusts a current I to the heating resistor according to the temperature difference value Ca,

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal 14 further includes a preset second current matrix Ib0 and a preset temperature difference matrix Cb0, and for the preset second current matrix Ib0, Ib0(Ib1, Ib2, Ib3, Ib4) is set, where Ib1 is a first preset second current, Ib2 is a second preset second current, Ib3 is a third preset second current, Ib4 is a fourth preset second current, and the preset second currents are sequentially decreased; setting Cb0(Cb1, Cb2, Cb3 and Cb4) for the preset temperature rise difference value matrix Cb0, wherein Cb1 is a first preset temperature rise difference value, Cb2 is a second preset temperature rise difference value, Cb3 is a third preset temperature rise difference value, Cb4 is a fourth preset temperature rise difference value, and the preset temperature rise difference values are increased in sequence;

specifically, after the controller 15 controls the heating resistor 9 to heat the mold for D2 time, and the temperature sensor 12 detects that the corrected temperature Tbj > Tbi of the mold, the PLC terminal 14 calculates the difference Cb between the actual temperature and the maximum injection temperature, sets Cb equal to Tbi-Tbj, and after the calculation, the PLC terminal 14 controls the current I to the heating resistor 9 according to the difference Cb between the actual temperature and the maximum injection temperature,

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal 14 further includes a preset maximum current value Imax, a preset first current difference matrix Δ a0, and a preset temperature-increasing resistance wire length adjustment coefficient matrix Xa0, and for the preset first current difference matrix Δ a0, Δ a0(Δ a1, Δ a2, Δ a3, and Δ a4) is set, where Δ a1 is a first preset first current difference value, Δ a2 is a second preset first current difference value, Δ a3 is a third preset first current difference value, and Δ a4 is a fourth preset first current difference value, and the preset first current difference values are sequentially increased; for the preset heating resistance wire length adjusting coefficient matrixes Xa0 and Xa0(Xa1, Xa2, Xa3 and Xa4), wherein Xa1 is a first preset heating resistance wire length adjusting coefficient, Xa2 is a second preset heating resistance wire length adjusting coefficient, Xa3 is a third preset heating resistance wire length adjusting coefficient, Xa4 is a fourth preset heating resistance wire length adjusting coefficient, and Xa1, Xa2, Xa3 and Xa4 are set to be more than 1 and Xa1 and less than 2;

specifically, when the PLC terminal 14 sets a first current to the heating resistor as Iai, the first current Iai > Imax, and the temperature sensor detects that the actual temperature T of the mold is less than Tai, i is set to 1, 2, 3, 4, the PLC terminal obtains a difference Δ a between the first current Iai and the preset maximum current Imax;

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal is further provided with a preset minimum current value Imin, a preset second current difference matrix Δ b0, and a preset temperature reduction resistance wire length adjustment coefficient matrix Xb0, and for the preset second current difference matrix Δ b0, Δ b0(Δ b1, Δ b2, Δ b3, and Δ b4) is set, where Δ b1 is a first preset second current difference value, Δ b2 is a second preset second current difference value, Δ b3 is a third preset second current difference value, and Δ b4 is a fourth preset second current difference value, and each preset second current difference value increases in sequence; for the preset temperature-reducing resistance wire length adjustment coefficient matrixes Xa0 and Xa0(Xa1, Xa2, Xa3 and Xa4), wherein Xa1 is the length adjustment coefficient of the first preset temperature-reducing resistance wire, Xa2 is the length adjustment coefficient of the second preset temperature-reducing resistance wire, Xa3 is the length adjustment coefficient of the third preset temperature-reducing resistance wire, Xa4 is the length adjustment coefficient of the fourth preset temperature-reducing resistance wire, and Xa1, Xa2, Xa3, Xa4 and 1 are set to be more than 0.5 and Xa1 and more than Xa 3552 and Xa 4;

specifically, when the PLC terminal sets a second current to the heating resistor to Ibi, the second current Ibi is less than Imin, and the temperature sensor detects that the actual temperature T of the mold is less than Tai, setting i to 1, 2, 3, 4, the PLC terminal obtains a difference Δ b between the second current Ibi and the preset minimum current Imin;

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal is further provided with a preset heating time matrix ta0, and for the preset heating time matrix ta0, ta0(ta1, ta2, ta3, ta4) is set, where ta1 is a first preset heating time, ta2 is a second preset heating time, ta3 is a third preset heating time, and ta4 is a fourth preset heating time, and the preset heating times are sequentially increased.

Specifically, when the resistance wire of the heating resistor is adjusted to the maximum value by the PLC terminal 14 and T is less than Tai, the PLC terminal sends an instruction for increasing the heating time of the heating resistor to the controller according to the material type,

Referring to fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the automatic control system of an injection molding machine includes a motor 24 disposed in the equipment box 13 and a fan 25 connected to the motor, the PLC terminal further has a preset rotation speed matrix V0, and for the preset rotation speed matrix V0, V0(V1, V2, V3, and V4) is set, where V1 is a first preset rotation speed, V2 is a second preset rotation speed, V3 is a third preset rotation speed, and V4 is a fourth preset rotation speed, and the preset rotation speeds are sequentially increased.

Specifically, when the temperature sensor detects that the temperature Tb in the mold is greater than Tbi, the PLC terminal calculates a temperature difference Cb, sets Cb to Tb-Tbi, and after the calculation is completed, the PLC terminal 14 determines the rotation speed of the fan according to the temperature difference to dissipate heat of the equipment box 13,

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the PLC terminal 14 further includes a preset resistance wire length matrix Lb0 and a preset rotation speed adjustment coefficient matrix E0, and for the preset resistance wire length matrix Lb0, Lb0(Lb1, Lb2, Lb3, Lb4) is set, where Lb1 is a first preset resistance wire length, Lb2 is a second preset resistance wire length, Lb3 is a third preset resistance wire length, Lb4 is a fourth preset resistance wire length, and the preset resistance wire lengths are sequentially increased; setting E0(E1, E2, E3 and E4) for the preset rotating speed adjusting coefficient matrix E0, wherein E1 is a first preset rotating speed adjusting coefficient, E2 is a second preset rotating speed adjusting coefficient, E3 is a third preset rotating speed adjusting coefficient, E4 is a fourth preset rotating speed adjusting coefficient, and E1 is more than 1 and E2 is more than E3 and more than E4 is less than 2;

As shown in fig. 2, in the automatic control system of an injection molding machine according to the embodiment of the present invention, the automatic control system of an injection molding machine further includes an alarm 17 and a warning light 18, and when the difference between the temperature of the mold detected by the temperature sensor 12 and the highest injection molding temperature exceeds a fourth preset temperature deviation or the current sensor 12 detects that the variation of the current is abnormal, the PLC terminal 14 sends an instruction to start the warning light 18 and the alarm 17 to the controller 15.

Specifically, when the temperature sensor 12 detects that the temperature of the mold and the preset highest injection molding temperature exceed a preset temperature high difference value or when the current sensor 16 detects that the current variation does not conform to the preset current variation, the PLC terminal determines that the injection molding temperature is too high or the current is unstable, which may result in unsuccessful injection molding and requires a user to intervene to check the reason.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic control system of an injection molding machine, comprising:

when the material is P4, the PLC terminal controls the injection molding temperature to be Ta 4-Tb 4, wherein Ta4 is the preset lowest injection molding temperature, and Tb4 is the highest injection molding temperature;

the PLC terminal is further provided with a preset first current matrix Ia0 and a preset temperature lower difference matrix Ca0, and for the preset first current matrix Ia0, Ia0(Ia1, Ia2, Ia3 and Ia4) is set, wherein Ia1 is a first preset first current, Ia2 is a second preset first current, Ia3 is a third preset first current, Ia4 is a fourth preset first current, and the preset first currents are increased in sequence; for the preset temperature lower difference matrix Ca0, setting Ca0(Ca1, Ca2, Ca3, Ca4), where Ca1 is a first preset temperature lower difference, Ca2 is a second preset temperature lower difference, Ca3 is a third preset temperature lower difference, and Ca4 is a fourth preset temperature lower difference, and the preset temperature lower differences increase in sequence;

when Ca is larger than or equal to Ca4, the PLC terminal adjusts the current led to the heating resistor to Ia 4;

the PLC terminal is further provided with a preset maximum current value Imax, a preset first current difference matrix delta a0 and a preset temperature-raising resistance wire length adjustment coefficient matrix Xa0, and for the preset first current difference matrix delta a0, delta a0 (delta a1, delta a2, delta a3 and delta a4) is set, wherein the delta a1 is a first preset first current difference, the delta a2 is a second preset first current difference, the delta a3 is a third preset first current difference, the delta a4 is a fourth preset first current difference, and the preset first current differences increase in sequence; for the preset heating resistance wire length adjusting coefficient matrixes Xa0 and Xa0(Xa1, Xa2, Xa3 and Xa4), wherein Xa1 is a first preset heating resistance wire length adjusting coefficient, Xa2 is a second preset heating resistance wire length adjusting coefficient, Xa3 is a third preset heating resistance wire length adjusting coefficient, Xa4 is a fourth preset heating resistance wire length adjusting coefficient, and Xa1, Xa2, Xa3 and Xa4 are set to be more than 1 and Xa1 and less than 2;

2. The automatic control system of an injection molding machine according to claim 1, wherein the PLC terminal is further provided with a preset material mass matrix M0 and a preset temperature-lowering correction coefficient matrix Ka0, and for the material mass matrix M0, M0(M1, M2, M3, M4) is set, wherein M1 is a first preset material mass, M2 is a second preset material mass, M3 is a third preset material mass, and M4 is a fourth preset material mass, and the preset material masses are sequentially increased; setting Ka0(Ka1, Ka2, Ka3 and Ka4) for the preset temperature lower correction coefficient matrix Ka0, wherein Ka1 is a first preset temperature lower correction coefficient, Ka2 is a second preset temperature lower correction coefficient, Ka3 is a third preset temperature lower correction coefficient, Ka4 is a fourth preset temperature lower correction coefficient, and 1 & lt Ka1 & lt Ka2 & lt Ka3 & lt Ka4 & lt 2;

the PLC terminal sets the injection molding temperature range to Tai-Tbi, sets i to 1, 2, 3, 4, the PLC terminal obtains the mass M of the material in the mold after the controller controls the heating resistor to heat the mold for D1 time, the temperature sensor detects that the actual temperature T of the mold is more than Tbi, selects a corresponding higher temperature correction coefficient Kb according to the mass M of the material to correct the injection molding temperature so as to enable the actual temperature T of the mold to reach the preset injection molding temperature range Tai-Tbi,

3. The automatic control system of an injection molding machine according to claim 2, wherein the PLC terminal is further provided with a preset second current matrix Ib0 and a preset temperature rise difference matrix Cb0, and for the preset second current matrix Ib0, Ib0(Ib1, Ib2, Ib3, Ib4) is set, where Ib1 is a first preset second current, Ib2 is a second preset second current, Ib3 is a third preset second current, Ib4 is a fourth preset second current, and the preset second currents decrease in order; setting Cb0(Cb1, Cb2, Cb3 and Cb4) for the preset temperature rise difference value matrix Cb0, wherein Cb1 is a first preset temperature rise difference value, Cb2 is a second preset temperature rise difference value, Cb3 is a third preset temperature rise difference value, Cb4 is a fourth preset temperature rise difference value, and the preset temperature rise difference values are increased in sequence;

4. The automatic control system of an injection molding machine according to claim 3, wherein the PLC terminal is further provided with a preset minimum current value Imin, a preset cooling current difference matrix Δ b0 and a preset cooling resistance wire length adjustment coefficient matrix Xb0, and for the preset cooling current difference matrix Δ b0, Δ b0(Δ b1, Δ b2, Δ b3, Δ b4) is set, wherein Δ b1 is a first preset cooling current difference value, Δ b2 is a second preset cooling current difference value, Δ b3 is a third preset cooling current difference value, and Δ b4 is a fourth preset cooling current difference value, and each preset cooling current difference value is increased in sequence; for the preset cooling resistance wire length adjustment coefficient matrixes Xb0 and Xb0(Xb1, Xb2, Xb3 and Xb4), wherein Xb1 is a first preset cooling resistance wire length adjustment coefficient, Xb2 is a second preset cooling resistance wire length adjustment coefficient, Xb3 is a third preset cooling resistance wire length adjustment coefficient, Xb4 is a fourth preset cooling resistance wire length adjustment coefficient, and Xb1, Xb2, Xb3 and Xb4 are set to be 0.5 < Xb1 < Xb2 < Xb3 < Xb4 < 1;

5. The automatic control system of an injection molding machine according to claim 4, wherein the PLC terminal is further provided with a preset heating time matrix ta0, for the preset heating time matrix ta0, ta0(ta1, ta2, ta3, ta4) is set, wherein ta1 is a first preset heating time, ta2 is a second preset heating time, ta3 is a third preset heating time, ta4 is a fourth preset heating time, each preset heating time increasing in order;

6. The automatic control system of an injection molding machine according to claim 5, wherein the automatic control system of an injection molding machine comprises a motor disposed in the equipment box and a fan connected to the motor, the PLC terminal is further provided with a preset rotation speed matrix V0, and a V0(V1, V2, V3, V4) is set, wherein V1 is a first preset rotation speed, V2 is a second preset rotation speed, V3 is a third preset rotation speed, and V4 is a fourth preset rotation speed, and the preset rotation speeds are increased in sequence;

when the temperature sensor detects that the temperature Tb in the mold is larger than Tbi, the PLC terminal calculates a temperature higher difference Cb, the Cb is set to Tb-Tbi, after calculation is finished, the PLC terminal determines the rotating speed of the fan according to the temperature higher difference to dissipate heat of the equipment box,

7. The automatic control system of an injection molding machine as claimed in claim 6, wherein the PLC terminal is further provided with a preset resistance wire length matrix Lb0 and a preset rotation speed adjustment coefficient matrix E0, for the preset resistance wire length matrix Lb0, Lb0(Lb1, Lb2, Lb3, Lb4) is set, wherein Lb1 is a first preset resistance wire length, Lb2 is a second preset resistance wire length, Lb3 is a third preset resistance wire length, Lb4 is a fourth preset resistance wire length, and the preset resistance wire lengths are increased in sequence; setting E0(E1, E2, E3 and E4) for the preset rotating speed adjusting coefficient matrix E0, wherein E1 is a first preset rotating speed adjusting coefficient, E2 is a second preset rotating speed adjusting coefficient, E3 is a third preset rotating speed adjusting coefficient, E4 is a fourth preset rotating speed adjusting coefficient, and E1 is more than 1 and E2 is more than E3 and more than E4 is less than 2;

8. The automatic control system of an injection molding machine according to claim 7, further comprising an alarm and an alarm lamp, wherein when the temperature sensor detects that the difference between the temperature of the mold and the maximum injection temperature exceeds a fourth preset temperature rise difference or when the current sensor detects that the variation of the current is abnormal, the PLC terminal sends an instruction to the controller to start the alarm lamp and the alarm.