System and Method for Controlling the Quality of Film Bubbles in a Film Blowing Machine

Abstract

An embodiment of the present invention provides a system for controlling the quality of a blown film bubble of a blown film machine, including: an image acquisition camera, a server, a host computer, a controller, a wind pressure detection sensor installed at the air outlet position of a wind ring fan, and a wind ring fan control frequency converter, which are installed at the same horizontal installation position as the die head of the blown film machine; the image acquisition camera is communicatively connected to the server, the server is communicatively connected to the host computer, the host computer is communicatively connected to the controller, the controller is electrically connected to the wind pressure detection sensor, and the controller is communicatively connected to the wind ring fan control frequency converter. By applying the solution provided by the embodiment of the present invention, image recognition technology is used to recognize the real-time change situation of the blown film bubble, and the wind ring fan control frequency converter is adjusted according to the change situation of the blown film bubble, so as to change the magnitude of the wind force of the wind ring fan and automatically control the size of the blown film bubble within the standard range, realizing the intelligentization and unmanned operation of the blown film process.

Description

Technical Field

[0001] The present invention relates to the technical field of blown film equipment, and particularly to a system and method for controlling the quality of the film bubble of a blown film machine. Background Art

[0002] A blown film machine is a device that heats and melts plastic particles and then blows them into a film. With the increasingly wide application of various films in production and life, the blown film machine technology has also developed rapidly.

[0003] During the production process of a blown film machine, the control level of the film bubble shape and appearance quality directly affects the product quality. In the related art, most manufacturers observe the film bubble shape through workers and manually adjust the wind force of the air ring fan to control the size of the film bubble within a certain range to ensure the quality of the film bubble. However, in this implementation method, the work intensity of workers is large and the automation level is low; in addition, some manufacturers use photoelectric sensing technology to detect the change of a certain point of the film bubble, that is, a pair of opposed switches are set on both sides of the film bubble. When the film bubble blocks the opposed switches, it is determined that the film bubble is too large, and then the wind force of the air ring fan is reduced. However, the opposed switches are easily blocked by other foreign objects and cause misjudgment, and the opposed switches cannot judge well in the case of too small film bubbles, and the automation degree is limited. Summary of the Invention

[0004] The embodiments of the present invention provide a system and method for controlling the quality of the film bubble of a blown film machine to achieve the technical effect of improving the automation level of the blowing film process.

[0005] On the one hand, the present invention provides a system for controlling the quality of the film bubble of a blown film machine, including: an image acquisition camera installed at the same horizontal installation position as the die head of the blown film machine, a server, a host computer, a controller, a wind pressure detection sensor installed at the air outlet position of the air ring fan, and an air ring fan control frequency converter;

[0006] The image acquisition camera is communicatively connected to the server, the server is communicatively connected to the host computer, the host computer is communicatively connected to the controller, the controller is electrically connected to the wind pressure detection sensor, and the controller is communicatively connected to the air ring fan control frequency converter.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: applying the solution provided by the embodiments of the present invention, using image recognition technology to identify the real-time change of the film bubble, and adjusting the air ring fan control frequency converter according to the change of the film bubble, and then changing the wind force of the air ring fan to automatically control the size of the film bubble within the standard range, realizing the intelligentization and unmanned operation of the blowing film process.

[0008] Optionally, it further includes: an extruder control frequency converter; the extruder control frequency converter is communicatively connected to the controller.

[0009] Optionally, it further includes: a heating ring sleeved on the die head, and a die head temperature sensor installed on the die head;

[0010] The controller is electrically connected to the heating ring and the die head temperature sensor.

[0011] Optionally, it further includes: a barrel temperature sensor installed on the extruder barrel, and the barrel temperature sensor is electrically connected to the controller.

[0012] Optionally, the host computer and the controller are communicatively connected based on the industrial Ethernet.

[0013] Optionally, the controller adopts a PLC controller.

[0014] In another aspect of the implementation of the present invention, a method for controlling the quality of the film bubble of a blown film machine is further provided. Applied to the above system, the method includes:

[0015] During the film blowing process of the blown film machine, the image acquisition camera acquires the real-time image of the film bubble and sends the real-time image to the server;

[0016] The server receives the real-time image, identifies the real-time contour of the film bubble included in the real-time image, compares the real-time contour with the standard contour, and sends the comparison result to the host computer;

[0017] After the host computer receives the comparison result, when it is determined based on the comparison result that the first deviation value of the real-time contour smaller than the standard contour exceeds the predetermined threshold, a control instruction to increase the operating frequency of the inverter controlled by the air ring blower is sent to the controller, and the controller increases the operating frequency of the inverter controlled by the air ring blower according to the predetermined frequency control rule;

[0018] When the host computer determines based on the comparison result that the second deviation value of the real-time contour larger than the standard contour exceeds the predetermined threshold, a control instruction to decrease the operating frequency of the inverter controlled by the air ring blower is sent to the controller, and the controller decreases the operating frequency of the inverter controlled by the air ring blower according to the predetermined frequency control rule.

[0019] Optionally, the process of the controller increasing the operating frequency of the inverter controlled by the air ring blower according to the predetermined frequency control rule includes:

[0020] The controller determines whether the air pressure at the air outlet position of the air ring blower is within the predetermined air pressure range based on the detection signal of the air pressure detection sensor;

[0021] When it is within the predetermined air pressure range, keep the operating frequency of the inverter controlled by the air ring blower unchanged and increase the operating frequency of the inverter controlled by the extruder;

[0022] When it is below the predetermined air pressure range, increase the operating frequency of the inverter controlled by the air ring blower.

[0023] Optionally, the process by which the controller controls the operating frequency of the frequency converter for the air ring fan to decrease according to a predetermined frequency control rule includes:

[0024] The controller determines whether the air pressure at the air outlet position of the air ring fan is within a predetermined air pressure range based on the detection signal of the air pressure detection sensor;

[0025] When it is within the predetermined air pressure range, keep the operating frequency of the frequency converter for the air ring fan unchanged and decrease the operating frequency of the frequency converter for the extruder;

[0026] When it is higher than the predetermined air pressure range, decrease the operating frequency of the frequency converter for the air ring fan.

[0027] Optionally, the method further includes: The server determines whether there is a process of change from large to small in the film bubble according to the real-time profile. If so, it sends a control instruction to the upper computer to decrease the operating frequency of the frequency converter for the air ring fan;

[0028] The controller decreases the operating frequency of the frequency converter for the air ring fan based on the control instruction. Description of the Drawings

[0029] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not limit the present invention. In the drawings:

[0030] Figure 1 It is a schematic structural diagram of a system for controlling the quality of the film bubble of a blown film machine provided by an embodiment of the present invention. Detailed Embodiments

[0031] To make the purpose, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with the embodiments and the drawings. Herein, the illustrative embodiments and descriptions thereof of the present invention are used to explain the present invention, but do not limit the present invention.

[0032] See Figure 1 , A system for controlling the quality of the film bubble of a blown film machine provided by an embodiment of the present invention includes: An image acquisition camera, a server, an upper computer, a controller, an air pressure detection sensor installed at the air outlet position of the air ring fan, and a frequency converter for controlling the air ring fan, which are installed at the same horizontal installation position as the die head of the blown film machine;

[0033] The image acquisition camera is communicatively connected to the server, the server is communicatively connected to the upper computer, the upper computer is communicatively connected to the controller, the controller is electrically connected to the air pressure detection sensor, and the controller is communicatively connected to the frequency converter for controlling the air ring fan.

[0034] In implementation, it further includes: an extruder control frequency converter; the extruder control frequency converter is communicatively connected to the controller.

[0035] In implementation, it further includes: a heating ring sleeved on the die head, and a die head temperature sensor installed on the die;

[0036] The controller is electrically connected to the heating ring and the die head temperature sensor, and the temperature of the die head is monitored in real time through the die head temperature sensor and the temperature of the die head is controlled by using the heating ring.

[0037] In implementation, it further includes: a barrel temperature sensor installed on the extruder barrel, and the barrel temperature sensor is electrically connected to the controller.

[0038] In implementation, the host computer and the controller are communicatively connected based on the industrial Ethernet.

[0039] In implementation, the controller adopts a PLC controller.

[0040] In implementation, the working process of the system for controlling the film bubble quality of the blown film machine provided by the embodiment of the present invention includes:

[0041] During the film blowing process of the blown film machine, the image acquisition camera acquires the real-time image of the film bubble and sends the real-time image to the server;

[0042] The server receives the real-time image, identifies the real-time contour of the film bubble included in the real-time image, compares the real-time contour with the standard contour, and sends the comparison result to the host computer;

[0043] After the host computer receives the comparison result, when it is determined based on the comparison result that the first deviation value of the real-time contour smaller than the standard contour exceeds the predetermined threshold, a control instruction for increasing the working frequency of the control frequency converter of the air ring fan is sent to the controller, and the controller increases the working frequency of the control frequency converter of the air ring fan according to the predetermined frequency control rule;

[0044] When the host computer determines based on the comparison result that the second deviation value of the real-time contour larger than the standard contour exceeds the predetermined threshold, a control instruction for reducing the working frequency of the control frequency converter of the air ring fan is sent to the controller, and the controller reduces the working frequency of the control frequency converter of the air ring fan according to the predetermined frequency control rule.

[0045] In implementation, the process of the controller increasing the working frequency of the control frequency converter of the air ring fan according to the predetermined frequency control rule includes:

[0046] The controller determines whether the air pressure at the air outlet position of the air ring fan is within the predetermined air pressure range based on the detection signal of the air pressure detection sensor;

[0047] When the wind pressure is within the predetermined range, keep the operating frequency of the inverter controlled by the air ring fan unchanged and increase the operating frequency of the inverter controlled by the extruder;

[0048] When the wind pressure is below the predetermined range, increase the operating frequency of the inverter controlled by the air ring fan.

[0049] In implementation, the process of the controller reducing the operating frequency of the inverter controlled by the air ring fan according to the predetermined frequency control rule includes:

[0050] The controller determines whether the wind pressure at the outlet position of the air ring fan is within the predetermined wind pressure range based on the detection signal of the wind pressure detection sensor;

[0051] When the wind pressure is within the predetermined range, keep the operating frequency of the inverter controlled by the air ring fan unchanged and reduce the operating frequency of the inverter controlled by the extruder;

[0052] When the wind pressure is above the predetermined range, reduce the operating frequency of the inverter controlled by the air ring fan.

[0053] In implementation, it also includes: The server determines whether there is a process of the film bubble changing from large to small according to the real-time profile. If so, it sends a control instruction to the upper computer to reduce the operating frequency of the inverter controlled by the air ring fan;

[0054] The controller reduces the operating frequency of the inverter controlled by the air ring fan.

[0055] In implementation, when the controller increases or decreases the operating frequency of the inverter, it can increase or decrease the operating frequency of the inverter according to a predetermined step size. The step size can be 1Hz, 2Hz, etc.; it can also increase or decrease the operating frequency according to a predetermined percentage based on the original operating frequency. The predetermined percentage can be 1%, 2%, etc.

[0056] In implementation, if the first deviation value of the real-time profile of the film bubble from the standard profile is beyond the predetermined threshold, it indicates that the current film bubble is too small, which may be caused by too small wind force of the air ring fan or too small extrusion amount of the extruder. Therefore, in this case, the film bubble can be enlarged by increasing the wind force of the air ring fan and / or the extrusion amount of the extruder to improve the film bubble quality; while if the first deviation value of the real-time profile of the film bubble from the standard profile is beyond the predetermined threshold, it indicates that the current film bubble is too large, which may be caused by too large wind force of the air ring fan or too large extrusion amount of the extruder. Therefore, in this case, the film bubble can be reduced by reducing the wind pressure of the air ring fan and / or the extrusion amount of the extruder to improve the film bubble quality;

[0057] If there is a process of change in the film bubble from large to small, it indicates that the film bubble has been blown out. This situation is due to the excessive wind force of the air ring fan, so it is necessary to reduce the wind force of the air ring fan.

[0058] Applying the solution provided by the embodiment of the present invention, the image recognition technology is used to identify the real-time change situation of the film bubble, and the air ring fan control frequency converter is adjusted according to the change situation of the film bubble, and then the size of the wind force of the air ring fan is changed to automatically control the size of the film bubble within the standard range, realizing the intelligence and unmanned operation of the film blowing process.

[0059] The above are only the preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method for controlling the quality of the film bubble of a blown film machine, characterized in that, it is applied to a system for controlling the quality of the film bubble of a blown film machine. The system includes an image acquisition camera, a server, a host computer, a controller, a wind pressure detection sensor installed at the air outlet position of the air ring fan, and a variable frequency controller for the air ring fan, which are installed at the same horizontal installation position as the die head of the blown film machine; the image acquisition camera is communicatively connected to the server, the server is communicatively connected to the host computer, the host computer is communicatively connected to the controller, the controller is electrically connected to the wind pressure detection sensor, and the controller is communicatively connected to the variable frequency controller for the air ring fan. The variable frequency controller for the air ring fan is used to control the wind force of the air ring fan. It further includes: a variable frequency controller for the extruder; the variable frequency controller for the extruder is communicatively connected to the controller, and the variable frequency controller for the extruder is used to control the extrusion amount of the extruder; the method includes: During the film blowing process of the blown film machine, the image acquisition camera acquires the real-time image of the film bubble and sends the real-time image to the server; The server receives the real-time image, identifies the real-time contour of the film bubble included in the real-time image, compares the real-time contour with the standard contour, and sends the comparison result to the host computer; After the host computer receives the comparison result, when it is determined based on the comparison result that the first deviation value of the real-time contour smaller than the standard contour exceeds a predetermined threshold, it sends a control instruction to increase the working frequency of the variable frequency controller for the air ring fan to the controller, and the controller increases the working frequency of the variable frequency controller for the air ring fan according to a predetermined frequency control rule; When the host computer determines based on the comparison result that the second deviation value of the real-time contour larger than the standard contour exceeds a predetermined threshold, it sends a control instruction to decrease the working frequency of the variable frequency controller for the air ring fan to the controller, and the controller decreases the working frequency of the variable frequency controller for the air ring fan according to a predetermined frequency control rule; The process by which the controller increases the working frequency of the variable frequency controller for the air ring fan according to a predetermined frequency control rule includes: The controller determines whether the wind pressure at the air outlet position of the air ring fan is within a predetermined wind pressure range based on the detection signal of the wind pressure detection sensor; When it is within the predetermined wind pressure range, keep the working frequency of the variable frequency controller for the air ring fan unchanged and increase the working frequency of the variable frequency controller for the extruder; When it is lower than the predetermined wind pressure range, increase the working frequency of the variable frequency controller for the air ring fan; The process by which the controller decreases the working frequency of the variable frequency controller for the air ring fan according to a predetermined frequency control rule includes: The controller determines whether the wind pressure at the air outlet position of the air ring fan is within a predetermined wind pressure range based on the detection signal of the wind pressure detection sensor; When it is within the predetermined wind pressure range, keep the working frequency of the variable frequency controller for the air ring fan unchanged and decrease the working frequency of the variable frequency controller for the extruder; When it is higher than the predetermined wind pressure range, decrease the working frequency of the variable frequency controller for the air ring fan.

2. The method according to claim 1, characterized in that, the method further includes: the server determines whether there is a process of change from large to small in the film bubble according to the real-time contour. If so, it sends a control instruction to decrease the working frequency of the variable frequency controller for the air ring fan to the host computer. The controller reduces the operating frequency of the control frequency converter of the air ring fan based on the control instruction.

3. The method according to claim 1, wherein, the system further includes: a heating ring sleeved on the die head, and a die orifice temperature sensor installed on the die head; the controller is electrically connected to the heating ring and the die orifice temperature sensor.

4. The method according to claim 1, wherein, the system further includes: a barrel temperature sensor installed on the extruder barrel, and the barrel temperature sensor is electrically connected to the controller.

5. The method according to claim 1, wherein, the host computer and the controller are communicatively connected based on the industrial Ethernet.

6. The method according to claim 1, wherein, the controller adopts a PLC controller.

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