CN116141645B - Automatic opening and closing die for hollow blow molding machine - Google Patents

Abstract

The invention discloses an automatic opening and closing die for a hollow blow molding machine, which belongs to the technical field of plastic processing, and mainly comprises the following components: the plastic product cooling device comprises a base, a guide plate, a fixed plate, a motor, an adjusting screw, a moving assembly, a die, a plastic thermometer, a guide assembly, a cooling device, a three-dimensional camera and a central control system, wherein the central control system is internally provided with a temperature value of a plastic parison in each state and a safe temperature drop slope when cooling the plastic parison, the cooling liquid flow rate of the cooling device is controlled and the temperature of the cooling liquid is adjusted by analyzing each thermodynamic property of the plastic parison, the plastic temperature change in each demolding cooling process is recorded, a function image is constructed, the function of the change of the plastic temperature in the demolding cooling process along with time is subjected to iterative calculation, the influence coefficient in an accurate heat release algorithm is ensured, the production quality of the plastic product is improved, and the working efficiency of cooling demolding is improved.

Description

Automatic opening and closing die for hollow blow molding machine

Technical Field

The invention relates to the technical field of blow molding machines, in particular to an automatic opening and closing die for a hollow blow molding machine.

Background

Tanks and fuel filler tubes made of thermoplastic materials are widely used in motor vehicles. It is known to manufacture them using extrusion-blow molding machines. The thermoplastic material is extruded by heating to melt, and then passes through an extrusion head to form a generally cylindrical parison, which descends to the level of a blow mold, is blown through a blowing needle to form a shell, and is further blown to cool and set.

Publication No. CN205310776U discloses a blow mould and an extrusion-blow moulding machine for manufacturing hollow bodies, wherein the blow mould comprises two mould halves, each of which is connected to a respective bottom plate, characterized in that at least one of the mould halves is translationally movable relative to its bottom plate between a moulding position and a final open position. According to the utility model, the blow mould is capable of being opened twice, i.e. after the mould base has been driven by the blow moulding machine to the maximum mould opening position, at least one mould half can also be moved towards its base in order to increase the distance between the two mould halves (i.e. the mould opening distance). Therefore, the requirement of the corresponding mould on the mould opening distance of the blow molding machine can be reduced, the capability of the blow molding machine for adapting to moulds with different sizes is improved, and a larger playing space is created for the design of the hollow body. The utility model also relates to an extrusion-blow moulding machine comprising the above-mentioned blow mould.

The device is not provided with a plastic thermometer, a three-dimensional camera and a central control system, and can not control the flow rate of cooling liquid of the cooling device and adjust the temperature of the cooling liquid by analyzing the thermodynamic properties of plastic parisons, so that the production quality of plastic products is low, and the working efficiency of blow molding is reduced.

Disclosure of Invention

Therefore, the invention provides an automatic opening and closing die for a hollow blow molding machine, which is used for solving the problem that the flow rate of cooling liquid of a cooling device cannot be controlled by analyzing each thermodynamic property of a plastic parison in the prior art.

In order to achieve the above purpose, the present invention provides the following technical solutions: an automatic opening and closing die for a hollow blow molding machine is characterized in that a central control system divides the blow molding process of a plastic parison into a molten state stage when the plastic parison enters the die and a solid state cooling stage after solidification of the plastic parison is completed, and the central control system can judge the stage of a plastic raw material according to a plastic temperature value detected by a plastic thermometer;

the central control system stores thermodynamic property and property data of the plastic raw materials, constructs an exothermic algorithm capable of guaranteeing the blow molding quality of the plastic raw materials according to the thermodynamic property and property data of the plastic raw materials, analyzes and calculates the plastic temperature value detected by the plastic thermometer through the exothermic algorithm, and controls the flow rate of cooling liquid in the cooling device according to the calculation result;

The central control system calculates the flow rate of the cooling liquid of the cooling device in the molten state according to the safe heat release time length of the molten state;

the central control system is provided with a basic detection time period in the solid-state cooling stage, the central control system can determine a plastic temperature expected value which needs to be reached by a plastic product when the basic detection time period is ended according to the plastic temperature detected by the plastic thermometer when the basic detection time period is started, and calculate the cooling liquid flow rate in the cooling device in the basic detection time period according to the plastic temperature value when the basic detection time period is started and the plastic temperature expected value which needs to be reached by the plastic product, and control the cooling device to cool the plastic by using the cooling liquid flow rate;

when each basic detection duration is over, the central control system compares the actual temperature value of the plastic product with the temperature expected value determined when the basic detection duration is started, and the central control system can adjust the heat release algorithm through the comparison result;

the central control system detects the temperature of the plastic product in real time by controlling the plastic thermometer, and makes a difference between the temperature of the plastic product and the temperature of the cooling liquid returned by the cooling device, and adjusts the flow rate of the cooling liquid of the cooling device according to the temperature difference value, when the flow rate of the cooling liquid reaches a certain value, the central control system controls the cooling device to cool the cooling liquid according to the temperature difference value;

The central control system records the temperature from the time of entering the mold to the time of demolding each plastic product, constructs a function of the temperature changing along with time, analyzes and iterates each function, and corrects the heat release algorithm stored in the central control system through the iteration result.

In particular, thermodynamic properties and property data of the plastic raw materials are stored in the central control system:

the state of the plastic parison when entering the mold is a molten state;

the state of the plastic product after cooling is a demoulding state;

specific heat capacity Cp of the plastic raw material;

the temperature thetar of the plastic parison in the molten state;

latent heat of fusion Qm of plastic raw material;

the demolding temperature thetat of the plastic product;

the mass Z of the individual plastic articles;

the safe heat release time t1 of the molten state required by the release Qm of the plastic parison;

the central control system stores an endothermic conversion coefficient A of the cooling device;

calculating the heat release quantity Q of the plastic raw material from a molten state to a demolding state in a central control system, and setting Q= [ Cp (thetar-thetat) +qm ]. Times.Z;

calculating a temperature difference influence value B of the cooling liquid and the plastic product in the central control system, and setting B= (thetas-beta s) x L, wherein thetas is the real-time temperature of the plastic product, beta s is the real-time temperature of the cooling liquid, and L is a temperature difference influence coefficient arranged in the central control system;

The central control system calculates the flow rate Vm of the cooling liquid of the cooling device in the molten state by using the molten state safe heat release time period t1, and vm=qm/(a×b×t1).

Further, an automatic mold opening and closing device for a hollow blow molding machine comprises,

the base is arranged on the ground and used for fixing the die;

the automatic mold opening and closing module is arranged on the base and used for controlling the mold to automatically open and close;

the mold comprises a left mold and a right mold, and is arranged in the automatic mold opening and closing module and is used for providing blow molding shapes for plastic parisons;

a plastic thermometer disposed in the mold for monitoring a temperature of the plastic article;

the cooling device is arranged on the automatic die opening and closing module and is communicated with the die through a cooling hose, cooling liquid in the cooling device can enter the die shell through the cooling hose, the cooling device can detect the temperature of the cooling liquid, and the cooling liquid can be cooled and the flow rate of the cooling liquid can be controlled;

the three-dimensional camera is arranged on the automatic mold opening and closing module and is used for detecting the three-dimensional shape of the plastic product;

the central control system is arranged on the base, is connected with the automatic die opening and closing module, the three-dimensional camera, the plastic thermometer and the cooling device through a signal transmission line, and is used for controlling the cooling device to adjust the flow rate of cooling liquid and controlling the cooling device to cool the temperature of the cooling liquid by analyzing the thermodynamic properties of plastic parisons.

Further, a base guide groove is formed in the base;

the automatic mold opening and closing module comprises,

the left guide plate is arranged at the left position of the base, a circular through hole is formed in the middle of the left guide plate, guide plate guide grooves are formed in the upper portion and the lower portion of the circular through hole, and balls are arranged in the guide plate guide grooves;

the right guide plate is arranged at the right position of the base, a circular through hole is formed in the middle of the right guide plate, guide plate guide grooves are formed in the upper portion and the lower portion of the circular through hole, and balls are arranged in the guide plate guide grooves;

the left fixing plate is arranged at the left end of the base;

the right fixing plate is arranged at the right end of the base;

the left motor is arranged on the right side of the left fixing plate and is used for providing power in the horizontal direction for the left side die;

the right motor is arranged at the left side of the right fixing plate and is used for providing power in the horizontal direction for the right side die;

a left adjusting screw coaxially connected with the left motor for transmitting the rotation motion of the motor;

a right adjusting screw coaxially connected to the right motor for transmitting the rotational motion of the motor;

the left moving assembly comprises a left adjusting screw pipe and a left guide bar, wherein the left adjusting screw pipe is connected with the left adjusting screw rod through threads and penetrates through a circular through hole of the left guide plate, and the left guide bar can slide in the guide plate guide groove along the horizontal direction and is used for converting the rotary motion of the left motor into horizontal motion;

The right moving assembly comprises a right adjusting screw pipe and a right guide bar, wherein the right adjusting screw pipe is connected with the right adjusting screw rod through threads and penetrates through a circular through hole of the right guide plate, and the right guide bar can slide in the guide groove of the guide plate along the horizontal direction and is used for converting the rotary motion of the right motor into horizontal motion;

the left guide assembly is arranged at the lower part of the left die and comprises a connecting rod and a guide ball, and the guide ball can slide along the base guide groove in the horizontal direction;

the right guide assembly is arranged at the lower part of the right die and comprises a connecting rod and a guide ball, and the guide ball can slide along the base guide groove in the horizontal direction.

In particular, the central control system divides the overall exothermic process of the plastic parison into two procedures,

the central control system sets the process of releasing heat in the molten state of the plastic parison as a molten heat release program;

the central control system sets a process of changing a plastic parison into a solid state and releasing heat when the temperature is changed as a solid state cooling program;

the central control system reads temperature information returned by the plastic thermometer in real time in a molten state of the plastic parison, and when the value in the obtained temperature information changes, the central control system judges that the molten heat release process of the plastic parison is finished, judges that the plastic product is in a solid state, and enters a solid cooling process of the plastic product;

The central control system is internally provided with a basic detection duration t2, enters a plastic product solid-state cooling program, reads temperature information of the plastic product returned by the plastic thermometer every basic detection duration t2, calculates a safety slope k of the temperature of the plastic product, which is reduced along with time, and sets k=i/Qc, wherein Qc is a plastic temperature value detected by the plastic thermometer at the beginning of each basic detection duration t2, and I is a safety cooling coefficient arranged in the central control system;

the central control system calculates expected values Qy, qy=Qc-k multiplied by t2 of the plastic temperature when each basic detection time period t2 is finished;

the central control system is internally provided with an exothermic algorithm of plastic products in each basic detection time period t2 in the solid-state cooling procedure: cp (Qc-Qy). Times.Z=A.times.B.times.V.times.t2, where Qc-Qy is k.times.t2,

the central control system can calculate the cooling liquid flow rate Vi of the cooling device in the ith basic detection duration t2 in the solid-state cooling program, wherein Vi=CpxZ× (ki×t2)/(A×B×t2), wherein ki is the safety slope of the temperature drop of the plastic product in the ith basic detection duration t2 along with time.

In particular, when the ith basic detection time period t2 is finished, the central control system reads the actual temperature Qe of the plastic product returned by the plastic thermometer, calculates the absolute value Qz of the difference between Qe and Qy, qz= - |qe-qy|,

If Qz is less than or equal to Qp, the central control system judges that the actual temperature Qe of the plastic product accords with the expected value Qy of the plastic temperature when the ith basic detection duration t2 is ended, and the safety cooling coefficient I preset in the central control system is correct;

if Qz is more than Qp, the central control system judges that the actual temperature Qe of the plastic product does not accord with the expected value Qy of the plastic temperature when the ith basic detection duration t2 is ended;

wherein Qp is a difference evaluation parameter between the actual temperature Qe of the plastic product and the expected value Qy of the plastic temperature;

if Qz is larger than Qp and Qe is smaller than Qy, the central control system judges that the preset value of the safe cooling coefficient I is higher, adjusts the value of the I,

if Qz is greater than Qp and Qe is greater than Qy, the central control system determines that the preset safe cooling coefficient I is lower in value and adjusts the value of I,

when Qz is greater than Qp and Qe is less than Qy or when Qz is greater than Qp and Qe is greater than Qy, the central control system adjusts the value of the safe cooling coefficient I, and the adjusted safe cooling coefficient is I2, I2=I× (Qe/Qy).

In particular, in each basic detection time period t2, the central control system reads the temperature value θ ' of the plastic product returned by the plastic thermometer after the change and the temperature value β ' of the cooling liquid returned by the cooling device after the change in real time, calculates the temperature difference influence value B ' of the cooling liquid after the change and the plastic product, compares the temperature difference influence value B ' after the change with the temperature difference influence value B before the change, adjusts the cooling liquid flow velocity V of the cooling device according to the change of the temperature difference influence value of the cooling liquid and the plastic product, and the adjusted cooling liquid flow velocity is V ', V ' =v× (B '/B).

In particular, the central control system is internally provided with a rated cooling liquid flow rate Ve of the cooling device, compares Ve with a real-time cooling liquid flow rate Vs,

if Vs is less than or equal to 0.8 Xve, the central control system judges that the flow rate of the cooling liquid has a rising adjusting space, and no information is sent out;

if Vs is more than 0.8 Xve, the central control system judges that the flow rate of the cooling liquid does not have a lifting adjusting space and controls the cooling device to cool the cooling liquid,

the central control system calculates the difference value between the real-time temperature value theta s of the plastic product and the real-time temperature value beta s of the cooling liquid, compares the difference value with the temperature difference judging interval (F1, F2) arranged in the central control system,

if θs- βs is more than or equal to F2, the central control system controls the cooling device to cool the cooling liquid with the power of W1, and W1=H2/(θs- βs) is set;

if F2 is more than thetas-beta s is more than F1, the central control system controls the cooling device to cool the cooling liquid with the power of W2, and W2=H2/(thetas-beta s) is set;

if θs- βs is less than or equal to F1, the central control system controls the cooling device to cool the cooling liquid with the power of W3, and W3=H2/(θs- βs) is set;

wherein H1 is a first cooling power coefficient arranged in the central control system, H2 is a second cooling power coefficient arranged in the central control system, H3 is a third cooling power coefficient arranged in the central control system, and H1 is more than H2 and less than H3.

Further, the central control system compares the real-time temperature theta s of the plastic product returned by the plastic thermometer with the demolding temperature theta t of the plastic product,

if θs is more than θt, the central control system judges that cooling of the plastic product is not finished, and signals are not sent to the motor;

if θs is less than or equal to θt, the central control system judges that cooling of the plastic product is finished, and controls the left motor and the right motor to start, and opens the die;

the standard shape three-dimensional modeling of the plastic product is arranged in the central control system;

the central control system controls the left die and the right die to be opened, controls the three-dimensional camera to detect the three-dimensional shape of the demoulded plastic product, performs comparison analysis on the three-dimensional shape of the plastic product and the three-dimensional modeling of the standard shape, and calculates the shape similarity alpha s;

the central control system is internally provided with a shape similarity reference value alpha c, and the central control system compares and analyzes the alpha s with the alpha c,

if the αs is more than or equal to αc, the central control system judges that the plastic product is not deformed during demolding, and the demolding temperature θt in the central control system is reasonable in value;

if αs is smaller than αc, the central control system judges that deformation occurs when the plastic product is demolded, the numerical value of the demolding temperature thetat arranged in the central control system is higher, the demolding temperature thetat is regulated, the regulated demolding temperature is thetat 1, thetat 1=thetat multiplied by U, wherein U is a demolding temperature regulating coefficient arranged in the central control system, and U is larger than 1;

When the next plastic product is demolded, the central control system compares the three-dimensional shape of the plastic product with the three-dimensional modeling of the standard shape, if the θt1 is unreasonable, the demolding temperature adjustment coefficient U is repeatedly used for adjusting the θt1, and the demolding temperature after n times of adjustment is θtn=θt1×Un until the central control system judges that the numerical value of the demolding temperature θtn is reasonable.

Further, after assigning a value to the nth demolding temperature, the central control system judges that the demolding temperature is reasonable in value, records the temperature from when the nth plastic product enters the mold to when the nth plastic product is demolded, constructs a function thetan (t) of the nth demolding working temperature changing along with time, and takes the thetan (t) as an nth prejudgement function thetan (t) of the temperature of the plastic product changing along with time;

the central control system is internally provided with a function similarity reference value gamma of temperature change along with time, calculates the similarity lambda of thetadn (t) and a function thetadn+1 (t) of the n+1th demoulding operation temperature along with time change, compares lambda with gamma,

if lambda is more than or equal to gamma, judging that the similarity of thetadn (t) and thetadn+1 (t) accords with the expectation, judging that the variation condition of the demolding working temperature at the n+1th time accords with the n pre-judging function, assigning the thetadn+1 (t) to the n+1th pre-judging function, and setting thetadn+1 (t) =thetadn (t);

If lambda < gamma, judging that the similarity of thetadn (t) and thetadn+1 (t) is not in accordance with the expectation, judging that the variation condition of the n+1th demoulding working temperature is not in accordance with an n pre-judging function, setting a pre-judging process function thetaz (t) in the central control system, and setting thetaz (t) = [ thetadn (t) +thetadn+1 (t) ]/2;

the central control system continues to calculate the similarity lambda 'of thetaz (t) and thetan+1 (t), compares lambda' with gamma,

if lambda' is not less than gamma, judging that the similarity of thetaz (t) and thetan+1 (t) accords with the expectation, assigning a value to an n+1-th pre-judging function thetadn+1 (t), and setting thetadn+1 (t) =thetaz (t);

if lambda ' < gamma, judging that the similarity between thetaz (t) and thetan+1 (t) is not in accordance with the expectation, repeating iterative operation on thetaz (t) and thetan+1 (t) by the central control system until the similarity between the iterative pre-judging process function thetaz ' (t) and thetan+1 (t) is larger than a similarity reference value gamma, assigning a value to a Q+1th pre-judging function thetadn+1 by the central control system, and setting thetadn+1=thetaz ' (t);

the central control system obtains thetadn+1 (t) through repeated iterative operation on a function of the demolding working temperature changing along with time, and substitutes thetadn+1, the temperature thetadn of the demolding temperature of the plastic product, the melting latent heat Qm of the plastic raw material, the mass Z of the single plastic product, the temperature difference influence value B of cooling liquid and the plastic product and the cooling liquid flow velocity V into thetadn+1 (t) in the n+1th demolding work, so as to obtain the adjusted heat absorption conversion coefficient an+1 of the cooling device, and establishes a new heat release algorithm qm=an+1×B×V×t2 and a new heat release algorithm Cp (Qc-Qy) ×Z=an+1×B×V×t2 in the n+1th demolding work.

Drawings

FIG. 1 is a schematic view of an automatic mold opening and closing structure for a blow molding machine according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a moving assembly according to an embodiment;

FIG. 3 is a schematic view of a guide assembly according to an embodiment;

FIG. 4 is a schematic diagram of an operation flow of an automatic mold opening and closing device for a hollow blow molding machine according to an embodiment of the present invention;

in the figure: 1. a base; 2. a left guide plate; 3. a right guide plate; 4. a left fixing plate; 5. a right fixing plate; 6. a cooling hose; 7. a left motor; 8. a right motor; 9. a left adjusting screw; 10. a right adjusting screw; 11. a three-dimensional camera; 12. a left die; 13. a right die; 14. a left adjusting screw tube; 15. right adjusting screw tube; 16. a left guide bar; 17. a right guide bar; 18. a connecting rod, 19, a guide ball; 20. a cooling device; 21. and a central control system.

Detailed Description

In order that the objects and advantages of the invention will become more apparent, the invention will be further described with reference to the following examples; it should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of 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 merely for explaining the technical principles of the present invention, and are not intended to limit the scope of the present invention.

It should be noted that, in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," "outer," and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, which are merely for convenience of description, and do not indicate or imply that the apparatus or elements must have a specific orientation, be constructed and operated in a specific orientation, 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 explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to the specific circumstances.

Referring to fig. 1, 2 and 3, fig. 1 is a schematic structural diagram of an automatic mold for a hollow blow molding machine according to an embodiment; FIG. 2 is a schematic diagram of a moving assembly according to an embodiment; FIG. 3 is a schematic view of a guide assembly according to an embodiment; FIG. 4 is a schematic diagram of an operation flow of an automatic mold opening and closing device for a hollow blow molding machine according to an embodiment of the present invention;

The invention provides an automatic opening and closing die for a hollow blow molding machine, which comprises,

a base 1 disposed on the ground for fixing the mold;

the automatic mold opening and closing module is arranged on the base 1 and used for controlling the mold to automatically open and close;

a mold including a left mold 12 and a right mold 13 provided in the mold automatic opening and closing module for providing a blow molding shape to a plastic parison;

a plastic thermometer (not shown) provided in the mold for monitoring the temperature of the plastic article;

the cooling device 20 is arranged on the automatic mold opening and closing module and is communicated with the mold through a cooling hose 6, cooling liquid in the cooling device 20 can enter the mold shell through the cooling hose 6, the cooling device 20 can detect the temperature of the cooling liquid, the cooling liquid can be cooled, and the flow rate of the cooling liquid can be controlled;

a three-dimensional camera 11 provided on the mold automatic opening and closing module for detecting a three-dimensional shape of a plastic product;

the central control system 21 is arranged on the base 1, is connected with the automatic mold opening and closing module, the three-dimensional camera 11, the plastic thermometer and the cooling device 20 through signal transmission lines, is internally provided with temperature values of plastic parisons in various states and safe temperature drop slopes when cooling the plastic parisons, and is used for controlling the cooling device 20 to regulate the flow rate of cooling liquid, controlling the cooling device 20 to cool the temperature of the cooling liquid, recording the temperature change of the plastic in each demolding cooling process, constructing a function image, carrying out iterative calculation on functions of the change of the plastic temperature in the demolding cooling process along with time, and correcting an exothermic algorithm stored in the central control system through iterative calculation results.

Further, a base guide groove is formed in the base 1;

the automatic mold opening and closing module comprises,

the left guide plate 2 is arranged at the left side of the base 1, a circular through hole is formed in the middle of the left guide plate, guide plate guide grooves are formed in the upper portion and the lower portion of the circular through hole, and balls are arranged in the guide plate guide grooves;

the right guide plate 3 is arranged at the right side of the base 1, a circular through hole is formed in the middle of the right guide plate, guide plate guide grooves are formed in the upper portion and the lower portion of the circular through hole, and balls are arranged in the guide plate guide grooves;

a left fixing plate 4 provided at the left end of the base 1;

a right fixing plate 5 disposed at the right end of the base 1;

a left motor 7 provided on the right side of the left fixing plate 4 for supplying power in the horizontal direction to the left die 12;

a right motor 8 provided on the left side of the right fixing plate 5 for supplying power in the horizontal direction to the right die 13;

a left adjusting screw 9 coaxially connected to the left motor 7 for transmitting the rotational movement of the motor;

a right adjusting screw 10 coaxially connected to the right motor 8 for transmitting the rotational movement of the motor;

a left moving assembly including a left adjusting screw 14 and a left guide bar 16 which are screw-coupled with the left adjusting screw 9 and pass through a circular through hole of the left guide plate 2, the left guide bar 16 being slidable in a horizontal direction in the guide plate guide groove for converting a rotational motion of the left motor 7 into a horizontal motion;

A right moving assembly including a right adjusting screw 15 and a right guide bar 17 which are screw-coupled to the right adjusting screw 10 and pass through a circular through hole of the right guide plate 3, the right guide bar 17 being slidable in a horizontal direction in the guide plate guide groove for converting a rotational motion of the right motor 8 into a horizontal motion;

the left guide assembly is arranged at the lower part of the left die 12 and comprises a connecting rod 18 and a guide ball 19, and the guide ball 19 can slide along the base guide groove in the horizontal direction;

the right guide assembly is arranged at the lower part of the right die 13 and comprises a connecting rod 18 and a guide ball 19, and the guide ball 19 can slide along the base guide groove in the horizontal direction.

By providing the guide ball 19 at the lower part of the mold and providing the base guide groove on the base 1, the movement of the mold in the horizontal direction can be restrained.

Further, thermodynamic properties and property data of the plastic raw materials are stored in the central control system 21, including:

the state of the plastic parison when entering the mold is a molten state;

the state of the plastic product after cooling is a demoulding state;

specific heat capacity Cp of the plastic raw material;

The temperature thetar of the plastic parison in the molten state;

latent heat of fusion Qm of plastic raw material;

the demolding temperature thetat of the plastic product;

the mass Z of the individual plastic articles;

the safe heat release time t1 of the molten state required by the release Qm of the plastic parison;

the central control system 21 stores an endothermic conversion coefficient A of the cooling device 20;

calculating the heat release quantity Q of the plastic raw material from a molten state to a demolding state in the central control system 21, and setting Q= [ Cp (thetar-thetat) +qm ]. Times.Z;

calculating a temperature difference influence value B of the cooling liquid and the plastic product in the central control system 21, and setting B= (thetas-beta s) x L, wherein thetas is the real-time temperature of the plastic product, beta s is the real-time temperature of the cooling liquid, and L is a temperature difference influence coefficient arranged in the central control system 21;

the central control system 21 calculates the flow rate Vm of the cooling liquid of the cooling device 20 in the molten state using the molten state safe heat release time period t1, and vm=qm/(a×b×t1).

If the heat release amount of the plastic parison in the molten state is not calculated, the cooling modes of the solid cooling procedure and the molten heat release procedure are the same in the whole heat release process, so that the heat release process of the crystalline material in the molten state is unreasonable, the surface of the plastic product is cracked, and the central control system 21 performs independent analysis and calculation on the heat release process of the plastic parison in the molten state by setting the safe heat release time length of the molten state, thereby ensuring the safe and reliable heat release process of the plastic product and avoiding the problem of cracking.

Further, the central control system 21 divides the overall exothermic process of the plastic parison into two procedures,

the central control system 21 sets the process of releasing heat in the molten state of the plastic parison as a melting heat release program;

the central control system 21 sets the process of changing the plastic parison into a solid state and releasing heat when the temperature is changed as a solid state cooling program;

the central control system 21 reads temperature information returned by the plastic thermometer in real time in a molten state of the plastic parison, when the value in the obtained temperature information changes, the central control system 21 judges that the molten heat release process of the plastic parison is finished, judges that the plastic product is in a solid state, and the central control system 21 enters a solid cooling process of the plastic product;

the central control system 21 is internally provided with a basic detection time period t2, the central control system 21 enters a solid cooling program of a plastic product, the central control system 21 reads temperature information of the plastic product returned by the plastic thermometer every basic detection time period t2, calculates a safety slope k of the temperature of the plastic product, which is reduced along with time, and sets k=i/Qc, wherein Qc is a plastic temperature value detected by the plastic thermometer at the beginning of each basic detection time period t2, and I is a safety cooling coefficient arranged in the central control system 21;

The central control system 21 calculates expected values Qy, qy=qc-k×t2 of the plastic temperature at the end of each basic detection time period t2;

the central control system 21 is internally provided with an exothermic algorithm of each basic detection duration t2 of the plastic product in the solid-state cooling procedure: cp (Qc-Qy). Times.Z=A.times.B.times.V.times.t2, where Qc-Qy is k.times.t2,

the central control system 21 can calculate the cooling fluid flow rate Vi of the cooling device 20 in the i-th basic detection period t2 in the solid-state cooling program, and vi=cp×z× (ki×t2)/(a×b×t2), where ki is the safety slope of the temperature decrease of the plastic product in the i-th basic detection period t2 over time.

If the safety slope of the temperature of the plastic product falling along with time is not set, the device falls too fast in the solid state cooling procedure, so that the surface of the plastic product is cracked to reduce the quality of the plastic product, or the temperature falls too slowly in the solid state cooling procedure, the production working efficiency is affected, and the central control system 21 provides a reference for the whole cooling process by setting the safety slope of the temperature of the plastic product falling along with time, so that the working efficiency is improved on the premise of ensuring the production quality.

Further, the central control system 21 reads the actual temperature Qe of the plastic product returned by the plastic thermometer at the end of the ith basic detection time period t2, calculates the absolute value Qz of the difference between Qe and Qy, qz= -Qe-qy|,

If Qz is less than or equal to Qp, the central control system 21 determines that the actual temperature Qe of the plastic product matches the expected value Qy of the plastic temperature when the ith basic detection duration t2 is ended, and the preset safe cooling coefficient I in the central control system 21 is correct;

if Qz > Qp, the central control system 21 determines that the actual temperature Qe of the plastic product does not match the expected value Qy of the plastic product at the end of the ith basic detection period t 2;

wherein Qp is a difference evaluation parameter between the actual temperature Qe of the plastic product and the expected value Qy of the plastic temperature;

if Qz is greater than Qp and Qe is less than Qy, the central control system 21 determines that the preset safe cooling coefficient I is higher in value and adjusts the value of I,

if Qz > Qp and Qe > Qy, the central control system 21 determines that the preset safe cooling coefficient I is lower in value and adjusts the value of I,

when Qz > Qp and Qe < Qy or when Qz > Qp and Qe > Qy, the central control system 21 adjusts the value of the safe cooling coefficient I, and the adjusted safe cooling coefficient is I2, i2=i× (Qe/Qy).

If the central control system 21 does not compare the actual temperature of the plastic product with the expected value of the plastic temperature, it cannot be judged whether the safety cooling coefficient set in the central control system 21 is wrong, so that the self-checking capability of the system is reduced, the system loophole cannot be corrected through self-checking, and the rationality of the safety cooling coefficient is verified by comparing the actual temperature of the plastic product with the expected value of the plastic temperature, so that the error correction capability and the self-adapting capability of the system are improved, and the device can perform cooling work under different environments.

Further, in each basic detection period t2, the central control system 21 reads the temperature value θ ' of the plastic product returned by the plastic thermometer after the change and the temperature value β ' of the cooling liquid returned by the cooling device 20 in real time, calculates the temperature difference influence value B ' of the cooling liquid after the change and the plastic product, compares the temperature difference influence value B ' after the change with the temperature difference influence value B before the change, and adjusts the cooling liquid flow velocity V of the cooling device 20 according to the change of the temperature difference influence value of the cooling liquid and the plastic product, where the adjusted cooling liquid flow velocity V ' is V ' =v× (B '/B).

Further, the central control system 21 is provided with a rated cooling fluid flow rate Ve of the cooling device 20, the central control system 21 compares Ve with a real-time cooling fluid flow rate Vs,

if Vs is less than or equal to 0.8XVe, the central control system 21 judges that the flow rate of the cooling liquid has a rising adjusting space, and does not send any information to the outside;

if Vs > 0.8 xe, the central control system 21 determines that the coolant flow rate does not have a rise adjustment space, and controls the cooling device 20 to cool the coolant,

the central control system 21 calculates the difference value between the real-time temperature value theta s of the plastic product and the real-time temperature value beta s of the cooling liquid, compares the difference value with the temperature difference judging sections (F1, F2) arranged in the central control system 21,

If θs- βs is greater than or equal to F2, the central control system 21 controls the cooling device 20 to cool the cooling liquid with the power of W1, and W1=H2/(θs- βs) is set;

if F2 > θs- βs > F1, the central control system 21 controls the cooling device 20 to cool the cooling liquid with the power of W2, and sets w2=h2/(θs- βs);

if θs- βs is less than or equal to F1, the central control system 21 controls the cooling device 20 to cool the cooling liquid with the power of W3, and W3=H2/(θs- βs) is set;

wherein H1 is a first cooling power coefficient arranged in the central control system, H2 is a second cooling power coefficient arranged in the central control system, H3 is a third cooling power coefficient arranged in the central control system, and H1 is more than H2 and less than H3.

If the cooling power of the cooling device 20 is not regulated, when the temperature difference between the cooling liquid and the plastic product is smaller and smaller after the flow rate of the cooling liquid reaches the rated flow rate, the cooling efficiency is reduced, and the central control system 21 increases the cooling power by controlling the cooling device 20, so that the temperature difference between the cooling liquid and the plastic product is kept within a normal range, and the working efficiency of the cooling device 20 is ensured.

Further, the central control system 21 compares the real-time temperature thetas of the plastic product returned by the plastic thermometer with the demolding temperature thetat of the plastic product,

If θs is greater than θt, the central control system 21 determines that cooling of the plastic product is not finished, and signals are not sent to the motor;

if θs is less than or equal to θt, the central control system 21 judges that cooling of the plastic product is finished, and controls the left motor 7 and the right motor 8 to start, and opens the mold;

the central control system 21 is internally provided with a standard shape three-dimensional modeling of plastic products;

the central control system 21 controls the left die 12 and the right die 13 to be opened, controls the three-dimensional camera 11 to detect the three-dimensional shape of the demoulded plastic product, performs comparison analysis on the three-dimensional shape of the plastic product and the three-dimensional modeling of the standard shape, and calculates the shape similarity alpha s;

the central control system 21 is internally provided with a shape similarity reference value alpha c, the central control system 21 carries out comparison analysis on the alpha s and the alpha c,

if αs is more than or equal to αc, the central control system 21 judges that the plastic product is not deformed during demolding, and the demolding temperature θt in the central control system 21 is reasonable in value;

if αs is less than αc, the central control system 21 determines that deformation occurs when the plastic product is demolded, the numerical value of the demolding temperature θt set in the central control system 21 is higher, the demolding temperature θt is regulated, the regulated demolding temperature is θt1, θt1=θtxU, wherein U is a demolding temperature regulation coefficient set in the central control system 21, and U is more than 1;

When the next plastic product is demolded, the central control system 21 compares the three-dimensional shape of the plastic product with the three-dimensional modeling of the standard shape, if it is judged that θt1 is unreasonable, the demolding temperature adjustment coefficient U is repeatedly used to adjust θt1, and the demolding temperature after n times of adjustment is θtn=θt1×U≡until the central control system 21 judges that the demolding temperature θtn is reasonable in value.

Further, the central control system 21 assigns a value to the nth demolding temperature and determines that the demolding temperature is reasonable, records the temperature from when the nth plastic product enters the mold to when the nth plastic product is demolded, constructs a function θn (t) of the nth demolding working temperature changing along with time, and takes the θn (t) as an nth prejudgement function θdn (t) of the plastic product temperature changing along with time;

the central control system 21 is internally provided with a function similarity reference value gamma of temperature change along with time, the central control system 21 calculates the similarity lambda of the function thetadn (t) and the function thetadn+1 (t) of the n+1th demoulding operation temperature along with time change, and compares the lambda with the gamma,

if lambda is more than or equal to gamma, judging that the similarity of thetadn (t) and thetadn+1 (t) accords with the expectation, judging that the variation condition of the demolding working temperature at the n+1th time accords with the n pre-judging function, assigning the thetadn+1 (t) to the n+1th pre-judging function, and setting thetadn+1 (t) =thetadn (t);

If λ < γ, determining that the similarity between θdn (t) and θn+1 (t) does not meet the expectation, determining that the n+1th demolding operation temperature change condition does not meet the n pre-determination function, setting a pre-determination process function θz (t) in the central control system 21, and setting θz (t) = [ θdn (t) +θn+1 (t) ]/2;

the central control system 21 continues to calculate the similarity lambda 'of thetaz (t) to thetan +1 (t), and compares lambda' to gamma,

if lambda' is not less than gamma, judging that the similarity of thetaz (t) and thetan+1 (t) accords with the expectation, assigning a value to an n+1-th pre-judging function thetadn+1 (t), and setting thetadn+1 (t) =thetaz (t);

if λ ' < γ, determining that the similarity between θz (t) and θn+1 (t) does not meet the expectation, the central control system 21 repeatedly iterates the operations between θz (t) and θn+1 (t) until the similarity between the iterated pre-determination process function θz ' (t) and θn+1 (t) is greater than the similarity reference value γ, and the central control system 21 assigns a value to the q+1 pre-determination function θdn+1, and sets θdn+1=θz ' (t).

Further, the central control system 21 performs repeated iterative operation on the function of the change of the demolding operation temperature with time to obtain θdn+1 (t), and substitutes the demolding temperature θtn+1 of the plastic product, the temperature θr of the plastic parison in the molten state, the latent heat Qm of melting the plastic raw material, the mass Z of the single plastic product, the temperature difference influence value B of the cooling liquid and the plastic product, and the cooling liquid flow velocity V into θdn+1 (t), so as to obtain the adjusted heat absorption conversion coefficient an+1 of the cooling device 20, and establishes a new heat release algorithm qm=an+1×b×v×t2 and a new heat release algorithm Cp (Qc-Qy) ×z=an+1×b×v×t2 in the n+1 demolding operation.

If the central control system 21 does not construct each cooling process into a function image and compare the function images, it cannot be judged whether the heat absorption conversion coefficient of the cooling device 20 arranged in the central control system 21 is wrong, so that the system is disordered, and the system loophole cannot be corrected through self-detection.

Thus far, the technical solution of the present invention has 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 protection of the present invention is not limited to these specific embodiments. Equivalent modifications and substitutions for related technical features may be made by those skilled in the art without departing from the principles of the present invention, and such modifications and substitutions will be within the scope of the present invention.

Claims (9)

1. An automatic opening and closing mold for a hollow blow molding machine, characterized by comprising,

the base is arranged on the ground and used for fixing the die;

The automatic mold opening and closing module is arranged on the base and used for controlling the mold to automatically open and close;

the mold comprises a left mold and a right mold, and is arranged in the automatic mold opening and closing module and is used for providing blow molding shapes for plastic parisons;

a plastic thermometer disposed in the mold for monitoring a temperature of the plastic article;

the cooling device is arranged on the automatic die opening and closing module and is communicated with the die through a cooling hose, cooling liquid in the cooling device can enter the die shell through the cooling hose, the cooling device can detect the temperature of the cooling liquid, and the cooling liquid can be cooled and the flow rate of the cooling liquid can be controlled;

the three-dimensional camera is arranged on the automatic mold opening and closing module and is used for detecting the three-dimensional shape of the plastic product;

the central control system is arranged on the base, is connected with the automatic die opening and closing module, the three-dimensional camera, the plastic thermometer and the cooling device through signal transmission lines, and controls the cooling device to regulate the flow rate of cooling liquid and controls the cooling device to cool the temperature of the cooling liquid by analyzing the thermodynamic properties of plastic parisons;

The central control system divides the blow molding process of the plastic parison into a molten state stage when the plastic parison enters the mold and a solid state cooling stage after the plastic parison is solidified, and the central control system can judge the stage of the plastic raw material according to the plastic temperature value detected by the plastic thermometer;

the central control system stores thermodynamic property and property data of the plastic raw materials, constructs an exothermic algorithm capable of guaranteeing blow molding quality of the plastic raw materials according to the thermodynamic property and property data of the plastic raw materials, analyzes and calculates a plastic temperature value detected by the plastic thermometer through the exothermic algorithm, and controls the flow rate of cooling liquid in the cooling device according to a calculation result;

the central control system calculates the flow rate of the cooling liquid of the cooling device in the molten state according to the safe heat release time length of the molten state;

the central control system is provided with a basic detection time period in the solid-state cooling stage, the central control system can determine a plastic temperature expected value which needs to be reached by a plastic product when the basic detection time period is ended according to the plastic temperature detected by the plastic thermometer when the basic detection time period is started, and calculate the cooling liquid flow rate in the cooling device according to the plastic temperature value when the basic detection time period is started and the plastic temperature expected value which needs to be reached by the plastic product, and control the cooling device to cool the plastic by using the cooling liquid flow rate;

When each basic detection duration is over, the central control system compares the actual temperature value of the plastic product with the temperature expected value determined when the basic detection duration is started, and the central control system can adjust the heat release algorithm through the comparison result;

the central control system detects the temperature of the plastic product in real time by controlling the plastic thermometer, and makes a difference between the temperature of the plastic product and the temperature of the cooling liquid returned by the cooling device, and adjusts the flow rate of the cooling liquid of the cooling device according to the temperature difference, when the flow rate of the cooling liquid reaches a certain value, the central control system controls the cooling device to cool the cooling liquid according to the temperature difference;

the central control system records the temperature from the time of entering the die to the time of demolding each plastic product, constructs a function of the temperature changing along with time, analyzes and iterates each function, and corrects the heat release algorithm stored in the central control system through the iteration result.

2. The automatic opening and closing mold for a hollow blow molding machine according to claim 1, wherein the thermodynamic properties and property data of the plastic raw material are stored in the central control system:

the state of the plastic parison when entering the mold is a molten state;

The state of the plastic product after cooling is a demoulding state;

specific heat capacity Cp of the plastic raw material;

the temperature thetar of the plastic parison in the molten state;

latent heat of fusion Qm of plastic raw material;

the demolding temperature thetat of the plastic product;

the mass Z of the individual plastic articles;

the safe heat release time t1 of the molten state required by the release Qm of the plastic parison;

the central control system stores an endothermic conversion coefficient A of the cooling device;

calculating the heat release quantity Q of the plastic raw material from a molten state to a demolding state in a central control system, and setting Q= [ Cp (thetar-thetat) +qm ]. Times.Z;

calculating a temperature difference influence value B of the cooling liquid and the plastic product in the central control system, and setting B= (thetas-beta s) x L, wherein thetas is the real-time temperature of the plastic product, beta s is the real-time temperature of the cooling liquid, and L is a temperature difference influence coefficient arranged in the central control system;

the central control system calculates the flow rate Vm of the cooling liquid of the cooling device in the molten state by using the molten state safe heat release time period t1, and vm=qm/(a×b×t1).

3. The automatic opening and closing mold for a hollow blow molding machine according to claim 2, wherein a base guide groove is provided on the base;

the automatic mold opening and closing module comprises,

the left guide plate is arranged at the left position of the base, a circular through hole is formed in the middle of the left guide plate, guide plate guide grooves are formed in the upper portion and the lower portion of the circular through hole, and balls are arranged in the guide plate guide grooves;

The right guide plate is arranged at the right position of the base, a circular through hole is formed in the middle of the right guide plate, guide plate guide grooves are formed in the upper portion and the lower portion of the circular through hole, and balls are arranged in the guide plate guide grooves;

the left fixing plate is arranged at the left end of the base;

the right fixing plate is arranged at the right end of the base;

the left motor is arranged on the right side of the left fixing plate and is used for providing power in the horizontal direction for the left side die;

the right motor is arranged at the left side of the right fixing plate and is used for providing power in the horizontal direction for the right side die;

a left adjusting screw coaxially connected with the left motor for transmitting the rotation motion of the motor;

a right adjusting screw coaxially connected to the right motor for transmitting the rotational motion of the motor;

the left moving assembly comprises a left adjusting screw pipe and a left guide bar, wherein the left adjusting screw pipe is connected with the left adjusting screw rod through threads and penetrates through a circular through hole of the left guide plate, and the left guide bar can slide in the guide plate guide groove along the horizontal direction and is used for converting the rotary motion of the left motor into horizontal motion;

the right moving assembly comprises a right adjusting screw pipe and a right guide bar, wherein the right adjusting screw pipe is connected with the right adjusting screw rod through threads and penetrates through a circular through hole of the right guide plate, and the right guide bar can slide in the guide groove of the guide plate along the horizontal direction and is used for converting the rotary motion of the right motor into horizontal motion;

The left guide assembly is arranged at the lower part of the left die and comprises a connecting rod and a guide ball, and the guide ball can slide along the base guide groove in the horizontal direction;

the right guide assembly is arranged at the lower part of the right die and comprises a connecting rod and a guide ball, and the guide ball can slide along the base guide groove in the horizontal direction.

4. An automatic opening and closing mold for a hollow blow molding machine according to claim 3, characterized in that the central control system divides the entire exothermic process of the plastic parison into two procedures,

the central control system sets the process of releasing heat in the molten state of the plastic parison as a molten heat release program;

the central control system sets a process of changing a plastic parison into a solid state and releasing heat when the temperature is changed as a solid state cooling program;

the central control system reads temperature information returned by the plastic thermometer in real time in a molten state of the plastic parison, and when the value in the obtained temperature information changes, the central control system judges that the molten heat release process of the plastic parison is finished, judges that the plastic product is in a solid state, and enters a solid cooling process of the plastic product;

the central control system is internally provided with a basic detection duration t2, enters a plastic product solid-state cooling program, reads temperature information of the plastic product returned by the plastic thermometer every basic detection duration t2, calculates a safety slope k of the temperature of the plastic product, which is reduced along with time, and sets k=i/Qc, wherein Qc is a plastic temperature value detected by the plastic thermometer at the beginning of each basic detection duration t2, and I is a safety cooling coefficient arranged in the central control system;

The central control system calculates expected values Qy, qy=Qc-k multiplied by t2 of the plastic temperature when each basic detection time period t2 is finished;

the central control system is internally provided with an exothermic algorithm of plastic products in each basic detection time period t2 in the solid-state cooling procedure: cp (Qc-Qy). Times.Z=A.times.B.times.V.times.t2, where Qc-Qy is k.times.t2,

the central control system can calculate the cooling liquid flow rate Vi of the cooling device in the ith basic detection duration t2 in the solid-state cooling program, wherein Vi=CpxZ× (ki×t2)/(A×B×t2), wherein ki is the safety slope of the temperature drop of the plastic product in the ith basic detection duration t2 along with time.

5. The automatic opening and closing mold for a blow molding machine according to claim 4, wherein the central control system reads the actual temperature Qe of the plastic product returned by the plastic thermometer at the end of the ith basic detection time period t2, calculates the absolute value Qz of the difference between Qe and Qy, qz= -i Qe-qy|,

if Qz is less than or equal to Qp, the central control system judges that the actual temperature Qe of the plastic product accords with the expected value Qy of the plastic temperature when the ith basic detection duration t2 is ended, and the safety cooling coefficient I preset in the central control system is correct;

if Qz is more than Qp, the central control system judges that the actual temperature Qe of the plastic product does not accord with the expected value Qy of the plastic temperature when the ith basic detection duration t2 is ended;

Wherein Qp is a difference evaluation parameter between the actual temperature Qe of the plastic product and the expected value Qy of the plastic temperature;

if Qz is larger than Qp and Qe is smaller than Qy, the central control system judges that the preset value of the safe cooling coefficient I is higher, adjusts the value of the I,

if Qz is greater than Qp and Qe is greater than Qy, the central control system determines that the preset safe cooling coefficient I is lower in value and adjusts the value of I,

when Qz is greater than Qp and Qe is less than Qy or when Qz is greater than Qp and Qe is greater than Qy, the central control system adjusts the value of the safe cooling coefficient I, and the adjusted safe cooling coefficient is I2, I2=I× (Qe/Qy).

6. The automatic opening and closing mold for a blow molding machine according to claim 5, wherein in each basic detection time period t2, the central control system reads the temperature value θ ' of the plastic product returned by the plastic thermometer and the temperature value β ' of the cooling liquid returned by the cooling device after the change in real time, calculates the temperature difference influence value B ' of the cooling liquid after the change and the plastic product, compares the temperature difference influence value B ' after the change with the temperature difference influence value B before the change, and adjusts the cooling liquid flow velocity V of the cooling device according to the change of the temperature difference influence value of the cooling liquid and the plastic product, wherein the adjusted cooling liquid flow velocity V is V ', V ' =v× (B '/B).

7. The automatic opening and closing mold for a hollow blow molding machine according to claim 6, wherein the central control system is provided with a rated cooling fluid flow rate Ve of the cooling device, compares Ve with a real-time cooling fluid flow rate Vs,

if Vs is less than or equal to 0.8 Xve, the central control system judges that the flow rate of the cooling liquid has a rising adjusting space, and no information is sent out;

if Vs is more than 0.8 Xve, the central control system judges that the flow rate of the cooling liquid does not have a lifting adjusting space and controls the cooling device to cool the cooling liquid,

the central control system calculates the difference value between the real-time temperature value theta s of the plastic product and the real-time temperature value beta s of the cooling liquid, compares the difference value with the temperature difference judging interval (F1, F2) arranged in the central control system,

if θs- βs is more than or equal to F2, the central control system controls the cooling device to cool the cooling liquid with the power of W1, and W1=H2/(θs- βs) is set;

if F2 is more than thetas-beta s is more than F1, the central control system controls the cooling device to cool the cooling liquid with the power of W2, and W2=H2/(thetas-beta s) is set;

if θs- βs is less than or equal to F1, the central control system controls the cooling device to cool the cooling liquid with the power of W3, and W3=H2/(θs- βs) is set;

Wherein H1 is a first cooling power coefficient arranged in the central control system, H2 is a second cooling power coefficient arranged in the central control system, H3 is a third cooling power coefficient arranged in the central control system, and H1 is more than H2 and less than H3.

8. The automatic opening and closing mold for a hollow blow molding machine according to claim 7, wherein the central control system compares a real-time temperature θs of the plastic product returned by the plastic thermometer with a demolding temperature θt of the plastic product,

if θs is more than θt, the central control system judges that cooling of the plastic product is not finished, and signals are not sent to the motor;

if θs is less than or equal to θt, the central control system judges that cooling of the plastic product is finished, and controls the left motor and the right motor to start, and opens the die;

the standard shape three-dimensional modeling of the plastic product is arranged in the central control system;

the central control system controls the left die and the right die to be opened, controls the three-dimensional camera to detect the three-dimensional shape of the demoulded plastic product, performs comparison analysis on the three-dimensional shape of the plastic product and the three-dimensional modeling of the standard shape, and calculates the shape similarity alpha s;

the central control system is internally provided with a shape similarity reference value alpha c, and the central control system compares and analyzes the alpha s with the alpha c,

If the αs is more than or equal to αc, the central control system judges that the plastic product is not deformed during demolding, and the demolding temperature θt in the central control system is reasonable in value;

if αs is smaller than αc, the central control system judges that deformation occurs when the plastic product is demolded, the numerical value of the demolding temperature thetat arranged in the central control system is higher, the demolding temperature thetat is regulated, the regulated demolding temperature is thetat 1, thetat 1=thetat multiplied by U, wherein U is a demolding temperature regulating coefficient arranged in the central control system, and U is larger than 1;

when the next plastic product is demolded, the central control system compares the three-dimensional shape of the plastic product with the three-dimensional modeling of the standard shape, if the θt1 is unreasonable, the demolding temperature adjustment coefficient U is repeatedly used for adjusting the θt1, and the demolding temperature after n times of adjustment is θtn=θt1×Un until the central control system judges that the numerical value of the demolding temperature θtn is reasonable.

9. The automatic opening and closing mold for a hollow blow molding machine according to claim 8, wherein the central control system assigns a value to the nth demolding temperature and judges that the demolding temperature is reasonable, records the temperature from the time of entering the mold to the time of demolding the nth plastic product, constructs a function θn (t) of the nth demolding operation temperature changing with time, and takes the θn (t) as an nth prejudgement function θdn (t) of the temperature change of the plastic product with time;

The central control system is internally provided with a function similarity reference value gamma of temperature change along with time, calculates the similarity lambda of thetadn (t) and a function thetadn+1 (t) of the n+1th demoulding operation temperature along with time change, compares lambda with gamma,

if lambda is more than or equal to gamma, judging that the similarity of thetadn (t) and thetadn+1 (t) accords with the expectation, judging that the variation condition of the demolding working temperature at the n+1th time accords with the n pre-judging function, assigning the thetadn+1 (t) to the n+1th pre-judging function, and setting thetadn+1 (t) =thetadn (t);

if lambda < gamma, judging that the similarity of thetadn (t) and thetadn+1 (t) is not in accordance with the expectation, judging that the variation condition of the n+1th demoulding working temperature is not in accordance with an n pre-judging function, setting a pre-judging process function thetaz (t) in the central control system, and setting thetaz (t) = [ thetadn (t) +thetadn+1 (t) ]/2;

the central control system continues to calculate the similarity lambda 'of thetaz (t) and thetan+1 (t), compares lambda' with gamma,

if lambda' is not less than gamma, judging that the similarity of thetaz (t) and thetan+1 (t) accords with the expectation, assigning a value to an n+1-th pre-judging function thetadn+1 (t), and setting thetadn+1 (t) =thetaz (t);

if lambda ' < gamma, judging that the similarity between thetaz (t) and thetan+1 (t) is not in accordance with the expectation, repeating iterative operation on thetaz (t) and thetan+1 (t) by the central control system until the similarity between the iterative pre-judging process function thetaz ' (t) and thetan+1 (t) is larger than a similarity reference value gamma, assigning a value to a Q+1th pre-judging function thetadn+1 by the central control system, and setting thetadn+1=thetaz ' (t);

The central control system obtains thetadn+1 (t) through repeated iterative operation on a function of the demolding working temperature changing along with time, and substitutes thetadn+1, the temperature thetadn of the demolding temperature of the plastic product, the melting latent heat Qm of the plastic raw material, the mass Z of the single plastic product, the temperature difference influence value B of cooling liquid and the plastic product and the cooling liquid flow velocity V into thetadn+1 (t) in the n+1th demolding work, so as to obtain the adjusted heat absorption conversion coefficient an+1 of the cooling device, and establishes a new heat release algorithm qm=an+1×B×V×t2 and a new heat release algorithm Cp (Qc-Qy) ×Z=an+1×B×V×t2 in the n+1th demolding work.