A full closed loop wall thickness control and profile following error detection control method and system

Abstract

The application relates to a full closed-loop wall thickness control and profile following error detection control method and system, wherein the method comprises the following steps: obtaining user profile requirements and setting a parison wall thickness axial variation curve, outputting a driving signal to an electro-hydraulic servo valve according to the parison wall thickness axial curve; controlling the electro-hydraulic servo valve according to the driving signal, so that the servo oil cylinder is driven to move the center rod of a blow molding machine up and down, and the blow molding machine head die gap is changed; receiving a feedback signal of an electronic ruler connected to the servo oil cylinder, comparing the feedback signal with a preset standard signal, judging the operation condition and obtaining a comparison result; receiving monitoring signals of each part of the blow molding process, comparing the actual operation information with a preset monitoring range, obtaining a comparison result; generating an adjustment signal according to the comparison result and the comparison result, adjusting each part of the blow molding process and the head die position, so that the dynamic closed-loop adjustment of the parison wall thickness is completed. The application has the effect that the parison wall thickness can be dynamically closed-loop controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blow molding machines, in particular to a full closed loop wall thickness control and contour following error detection control method and system. BACKGROUND

[0002] With the development of society, blow molding products are widely used in packaging food, beverage, cosmetics, medicine and daily necessities. Blow molding is a processing method of hollow plastic products, and hollow blow molding is a molding method for making plastic containers. Hollow blow molding is to make the plasticized parison adhere to the inner wall of the mold by air pressure, and the production method of the parison is extrusion, which extrudes the plastic melt heated and plasticized from various shaped die gaps to form various shaped barrel-shaped parisons.

[0003] In the blow molding process, the formation and blowing of the parison are the core of the blow molding process, and the quality of the parison formation and blowing directly affects the quality of the plastic product. The heating temperature, extrusion pressure and cooling time of the melt will directly affect the molding and blowing quality of the parison. If the parison wall thickness is not effectively controlled during the blow molding process, the cooled parison will have uneven thickness, and the stress generated by the parison wall will also be different, and the thin part is prone to breakage. Therefore, controlling the parison wall thickness is also important for improving product quality and reducing cost.

[0004] The wall thickness control method in the related art is to use a general hollow blow molding machine, and then to judge by manual operation. The temperature, extrusion pressure and cooling time of the product of the extruder are set manually to complete the production of a parison. However, the parison produced in this way will have other parts thickened to meet the strength requirement of the minimum wall thickness, so that the produced parison is not uniform in thickness. SUMMARY

[0005] In order to improve the phenomenon that the parison produced in the related art is not uniform in thickness, the present application provides a full closed loop wall thickness control and contour following error detection control method and system.

[0006] In a first aspect, the present application provides a full closed loop wall thickness control and contour following error detection control method, which adopts the following technical scheme:

[0007] A full closed loop wall thickness control and contour following error detection control method, comprising the following steps:

[0008] Obtaining user contour requirements and setting a parison wall thickness axial variation curve, and outputting a driving signal to an electro-hydraulic servo valve according to the parison wall thickness axial curve;

[0009] Controlling the electro-hydraulic servo valve according to the driving signal to drive the servo oil cylinder to move the blow molding machine center rod up and down, and change the blow molding machine head die gap.

[0010] receiving feedback signals from the electronic gauge connected to the servo cylinder, comparing the feedback signals with preset standard signals, judging the operation condition and obtaining the comparison result;

[0011] receiving monitoring signals from each part of the blow molding process, generating actual operation information and comparing the actual operation information with preset monitoring range, and obtaining the comparison result;

[0012] generating adjustment signals according to the comparison result and the comparison result, adjusting each part of the blow molding process and the position of the head die mouth, controlling the opening and closing degree of the die mouth, and completing the dynamic closed loop adjustment of the parison wall thickness.

[0013] According to the above technical scheme, first, the system obtains the user contour requirement and sets the parison wall thickness axial variation curve, outputs the driving signal to the electro-hydraulic servo valve according to the parison wall thickness axial variation curve, and opens the parison. The electro-hydraulic servo valve receives the driving signal and drives the servo cylinder to move, so that the center rod of the blow molding machine moves up and down to change the gap between the head die of the blow molding machine, so as to control the parison wall thickness. An electronic gauge is installed on the servo cylinder. The system receives feedback signals from the electronic gauge to obtain the movement condition of the center rod, compares the feedback signals with preset standard signals, judges the current operation condition, and obtains the comparison result. Then the system receives monitoring signals from each part of the blow molding process, generates actual operation information, and compares the actual operation information with preset monitoring range, and obtains the comparison result. After the comparison result and the comparison result are summarized, the system generates adjustment signals according to the comparison result and the comparison result, adjusts each part of the blow molding process and the position of the head die mouth, adjusts the forming process of the parison, controls the opening and closing degree of the die, and completes the dynamic closed loop adjustment of the parison wall thickness. By setting the parison wall thickness axial variation curve and receiving feedback signals and actual operation information, the parison wall thickness is dynamically adjusted, so that the parison wall thickness is uniform.

[0014] Further, the obtaining of the user contour requirement and the setting of the parison wall thickness axial variation curve include the following steps:

[0015] obtaining a plurality of parison control points according to the user contour requirement, and generating user demand parameters;

[0016] setting the parison wall thickness axial variation curve by using the user demand parameters within a preset forming time.

[0017] By adopting the above technical scheme, the system can obtain a plurality of parison control points according to the user contour requirement. The plurality of parison control points are the key to realize the user contour requirement. The system controls the parison wall thickness through the plurality of parison control points. The system generates user demand parameters from the plurality of parison control points to better set the parison wall thickness axial variation curve and control the parison wall thickness.

[0018] Further, the plurality of parison control points correspond to a plurality of set values on the parison wall thickness axial variation curve respectively, and the plurality of parison control points correspond to the plurality of set values one by one, and the parison control points automatically track the set values.

[0019] By adopting the above technical scheme, in order to ensure the quality of the plastic product, the system generates a plurality of set values according to a plurality of parison control points, the plurality of set values are located on the parison wall thickness axial variation curve, and the plurality of parison control points can accurately correspond to and track the plurality of set values, so as to control the wall thickness of the parison in accordance with the parison wall thickness axial variation curve.

[0020] Further, the driving signal is a corresponding voltage signal or current signal output according to the parison wall thickness axial curve.

[0021] By adopting the above technical scheme, each parison control point corresponds to a change point, that is, each change point can output a corresponding voltage signal or current signal to control the electro-hydraulic servo valve, and the electro-hydraulic servo valve can convert the voltage or current signal into a mechanical displacement signal with a certain operating force, so as to control the servo oil cylinder to work, thereby controlling the movement of the center rod to control the parison wall thickness.

[0022] Further, the feedback signal is a corresponding voltage signal generated after the electronic ruler senses the size of the gap between the head die port.

[0023] By adopting the above technical scheme, after the electronic ruler senses the size of the gap between the head die port, the electronic ruler generates a corresponding voltage signal according to the size of the gap and feeds back to the system.

[0024] Further, the monitoring signal includes a blow molding machine storage cylinder position monitoring signal, a voltage and current fluctuation monitoring signal of the electro-hydraulic servo valve, and a die port temperature monitoring signal.

[0025] By adopting the above technical scheme, during the blow molding process, each part is monitored to monitor the parison forming from multiple aspects, and the storage cylinder position in the blow molding machine, the voltage and current of the electro-hydraulic servo valve, and the die port temperature are monitored during the blow molding process to monitor possible problems in the parison forming process from multiple aspects.

[0026] Further, the feedback signal of the electronic ruler connected to the servo oil cylinder is received, and compared with a preset standard signal to judge the running condition and obtain the comparison result, including the following steps:

[0027] When the feedback signal does not match the preset standard signal, it indicates that the running condition deviates from the axial variation curve of the parison wall thickness, and the comparison result is the distance of the feedback signal deviating from the preset standard signal.

[0028] When the feedback signal matches the preset standard signal, it indicates that the running condition follows the axial variation curve of the parison wall thickness.

[0029] By adopting the above technical solution, when the feedback signal does not match the preset standard signal, it indicates that the running condition deviates from the axial variation curve of the parison wall thickness, i.e., the current wall thickness condition does not conform to the preset wall thickness condition, and the comparison result at this time is the distance of the feedback signal deviating from the preset standard signal, so as to make adjustment; when the feedback signal matches the preset standard signal, it indicates that the current running condition follows the axial variation curve of the parison wall thickness, i.e., the plurality of parison control points correspond to track the plurality of set values on the axial variation curve of the parison wall thickness, and at this time, adjustment is not needed.

[0030] Further, the receiving the monitoring signal of each part of the blow molding process and comparing with the preset monitoring range to obtain the comparison result comprises the following steps:

[0031] The actual running information includes blow molding machine accumulator position monitoring information, voltage and current fluctuation monitoring information of the electro-hydraulic servo valve, and die temperature monitoring information.

[0032] When the actual running information is located in the preset monitoring range, it indicates that the actual running information is normal running.

[0033] When the actual running information is not located in the preset monitoring range, it indicates that the actual running information is abnormal running.

[0034] By adopting the above technical solution, the blow molding machine accumulator position monitoring information, the voltage and current fluctuation monitoring information of the electro-hydraulic servo valve, and the die temperature monitoring information are collectively collected into actual running information and fed back to the system, and compared with the preset monitoring range; when the actual running information is located in the preset monitoring range, it indicates that in the current parison forming process, the parameters of each part of the blow molding machine are in the normal range and do not need to be adjusted; when the actual running information is not located in the preset monitoring range, it indicates that in the parison wall thickness forming process, some parts are not in the normal range, and the comparison result obtained at this time is used to make timely adjustment.

[0035] Further, the generating an adjustment signal according to the comparison result and the comparison result comprises the following steps:

[0036] The comparison result is adjusted based on the preset standard signal to generate a die position adjustment signal.

[0037] The comparison result is adjusted based on the preset monitoring range to generate a parameter adjustment signal.

[0038] By using the above technical solution, the feedback signal is adjusted based on the preset standard signal, the deviation between the feedback signal and the preset standard signal is obtained, and the center rod is adjusted according to the deviation; the comparison result is adjusted based on the preset monitoring range, that is, the part of the actual operation information not located in the preset monitoring range is adjusted based on the corresponding preset monitoring range, the numerical deviation between the actual operation information and the preset monitoring range is obtained, and the part of the system that needs to be adjusted is adjusted, so that the formation of the parison wall thickness is smooth.

[0039] In a second aspect, the application provides a full-closed-loop wall thickness control and contour following error detection control system, which adopts the following technical solution:

[0040] A full-closed-loop wall thickness control and contour following error detection control system comprises:

[0041] An acquisition module acquires user contour requirements and sets a parison wall thickness axial variation curve, and outputs a driving signal to an electro-hydraulic servo valve according to the parison wall thickness axial curve;

[0042] A control module controls the electro-hydraulic servo valve according to the driving signal, thereby driving a servo oil cylinder to move the center rod of the blow molding machine up and down to change the blow molding machine head die gap;

[0043] A comparison module receives a feedback signal of an electronic ruler connected to the servo oil cylinder, and compares the feedback signal with a preset standard signal to judge the operation condition and obtain the comparison result;

[0044] A comparison module receives monitoring signals of each part of the blow molding process, generates actual operation information, and compares the actual operation information with a preset monitoring range to obtain the comparison result;

[0045] An adjustment module generates an adjustment signal according to the comparison result and the comparison result, adjusts each part of the blow molding process and the head die position, thereby controlling the opening and closing degree of the die, and completes the dynamic closed-loop adjustment of the parison wall thickness.

[0046] By adopting the technical scheme, firstly, the first obtaining module obtains the user profile requirement and sets the axial variation curve of the parison wall thickness, and outputs a driving signal to the electro-hydraulic servo valve according to the axial curve of the parison wall thickness, and the control module controls the electro-hydraulic servo valve to convert the driving signal into a mechanical displacement signal with a certain operating force, so that the servo oil cylinder drives the center rod of the blow molding machine to move to change the gap between the die head and the die mouth to control the parison wall thickness. Then, the comparison module compares the feedback signal from the electronic ruler on the servo oil cylinder with the preset standard signal to judge the current operation and obtain the comparison result. Then, the comparison module receives the monitoring signals of each part of the blow molding process and the actual operation information, and compares them with the preset monitoring range to obtain the comparison result. Finally, the adjustment module generates an adjustment signal according to the comparison result and the comparison result to adjust each part of the blow molding process and adjust the electro-hydraulic servo valve to control the servo oil cylinder to adjust the position of the center rod, thereby controlling the parison wall thickness.

[0047] In summary, the present application has at least one of the following beneficial technical effects:

[0048] 1. By setting the axial variation curve of the parison wall thickness according to the user profile, and controlling the wall thickness of the parison according to the axial variation curve of the parison wall thickness, driving the electro-hydraulic servo valve to control the servo oil cylinder to move the center rod up and down to control the wall thickness of the parison, and the gap of the die mouth is fed back to the system through the electronic ruler, and the parameters of each part of the blow molding process are integrated into the actual operation information and fed back to the system, and the system adjusts according to the feedback information to dynamically control the wall thickness of the parison, so that the parison is uniform in thickness.

[0049] 2. By monitoring the gap change of the die mouth and comparing it with the preset standard signal, the operation deviating from the parison wall thickness axial curve is adjusted in time, and the wall thickness of the parison is dynamically adjusted in a closed loop to make the formed parison uniform in thickness. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a flow chart of a full-closed-loop wall thickness control and profile following error detection control method provided by the present application;

[0051] Figure 2 is a running flow chart of S1 in the present application;

[0052] Figure 3 is a running flow chart of S3 in the present application;

[0053] Figure 4 is a running flow chart of S4 in the present application;

[0054] Figure 5 is a running flow chart of S5 in the present application;

[0055] Figure 6 is a flow chart of a full closed loop wall thickness control and profile following error detection control system provided by the present application.

[0056] In the figure, 1, acquisition module; 2, control module; 3, comparison module; 4, comparison module; 5, adjustment module. DETAILED DESCRIPTION

[0057] The following will be combined with the Figure 1 -Appendix Figure 6 , the present application is further described in detail.

[0058] The present application discloses a full closed loop wall thickness control and profile following error detection control method, as shown in Figure 1 .

[0059] A full closed loop wall thickness control and profile following error detection control method, refer to Figure 1 , comprising the following steps:

[0060] S1, get the user profile requirements and set the parison wall thickness axial variation curve, according to the parison wall thickness axial curve output drive signal to electro hydraulic servo valve.

[0061] In the blow molding machine, before making plastic products, need to make good parison, in order to subsequent according to the structure of parison production place the same size specifications of plastic products. In the production of parison, the wall thickness control of parison is very important, the wall thickness of parison will affect the quality of plastic products. The role of blow molding machine head of blow molding machine is to fuse the plastic after melting, and form parison. Blow molding machine in the automatic control of parison wall thickness mainly through the axial control, and the axial control adopts the closed loop control technology. Axial wall thickness control technology is to make the plastic parison extruded by blow molding machine, according to the different blow ratio of product along the axial direction to obtain different thickness, so as to ensure that the final product has more uniform wall thickness. Axial wall thickness control technology is to change the opening degree of the head by making the die mouth move axially according to the preset position, so as to change the wall thickness of the parison.

[0062] Before the parison wall thickness control, the user profile requirements need to be obtained to set the parison wall thickness axial variation curve, wherein the user profile requirements are the parison with the wall thickness required by the user, and the parison wall thickness axial variation curve is the change of parison wall thickness in the process of making parison.

[0063] Referring to Figure 2 , the user profile requirements are obtained and the parison wall thickness axial variation curve is set, comprising the following steps:

[0064] S11, according to the user profile requirements, a plurality of parison control points are obtained, and user demand parameters are generated.

[0065] Specifically, the user profile demand system will obtain a plurality of parison control points, which are the key to whether the user profile demand can be achieved, and the system will control the wall thickness of the parison through the plurality of parison control points. The system will generate user demand parameters from the plurality of parison control points to better set the parison wall thickness axial variation curve.

[0066] S12, set the parison wall thickness axial variation curve according to the user demand parameters within the preset forming time.

[0067] Specifically, each parison manufacturing process requires a certain time, which is the preset forming time. In the system, the preset forming time is configured in advance in the system according to the manufacturing of different parisons. The system sets the parison wall thickness axial variation curve according to the user demand parameters, and each change of the parison wall thickness axial curve corresponds to a parison control point.

[0068] And the plurality of parison control points correspond to a plurality of set values on the parison wall thickness axial variation curve, and the plurality of parison control points correspond to the plurality of set values one by one, and the parison control point automatically tracks the set value.

[0069] Specifically, in order to ensure the quality of the plastic product, the system will generate a plurality of set values from the plurality of parison control points, and the plurality of set values are located on the parison wall thickness axial variation curve. The plurality of parison control points can accurately correspond to and track the plurality of set values.

[0070] For example, to determine 10 parison control points, based on the continuous extrusion of the blow molding machine, it takes about 5 seconds to extrude a parison from the blow molding machine nozzle. A limited length function curve needs to be set, and 10 parison control points need to be inserted within 5 seconds. On the time axis, each part has only about 0.5 seconds. According to the setting that the plurality of parison control points need to track the plurality of set values, the parison control point tracking and transition time should be 1 / 5-1 / 10 of a part of time, i.e. 0.05-0.1 seconds, which requires fast response so that each parison control point can track each set value.

[0071] When the parison wall thickness axial variation curve is set, a drive signal is output to the electro-hydraulic servo valve according to the parison wall thickness axial curve. The drive signal is an output corresponding voltage signal or current signal according to the parison wall thickness axial curve, and each parison control point corresponds to a change point, i.e. each change point can output a corresponding voltage signal or current signal to control the electro-hydraulic servo valve.

[0072] S2, control the electro-hydraulic servo valve according to the drive signal to drive the servo oil cylinder to move the blow molding machine center rod up and down to change the blow molding machine nozzle gap.

[0073] Specifically, the electro-hydraulic servo valve converts the electrical signal, i.e. voltage or current signal, into a mechanical displacement signal with a certain operating force, so as to control the servo cylinder to extend or retract. The electro-hydraulic servo valve is connected with the servo cylinder, and the piston rod of the servo cylinder is connected with the center rod of the blow molding machine and can drive the center rod to move up and down.

[0074] The center rod is an important part in the head of the blow molding machine, which can open and close the die gap to change the die gap. The wall thickness control is to control the opening and closing degree of the die gap, and the core of the control is the position of the center rod of the blow molding machine. The control accuracy of the position of the center rod is the key to determine the effect of the parison wall thickness control.

[0075] After driving the servo cylinder to move the center rod of the blow molding machine up and down to change the die gap, the following steps are performed:

[0076] S3, receiving the feedback signal of the electronic ruler connected to the servo cylinder, and comparing with the preset standard signal to judge the running condition and obtain the comparison result.

[0077] Specifically, the piston rod of the servo cylinder is provided with an electronic ruler, which is a position sensor and can sense the change of the position, i.e. the change of the position of the center rod, to sense the change of the die gap. The feedback signal is the voltage signal generated by the electronic ruler after sensing the size of the die gap. After sensing the size of the die gap of the head, the electronic ruler generates a corresponding voltage signal of the size of the gap and feeds back to the system. In the system, the feedback signal is compared with the preset standard signal to judge the running condition and obtain the comparison result, as shown in Figure 3 , the specific steps are as follows:

[0078] S31, when the feedback signal does not match the preset standard signal, it means that the running condition deviates from the parison wall thickness axial change curve, and the comparison result is the distance between the feedback signal and the preset standard signal.

[0079] The preset standard signal is the voltage signal corresponding to the parison wall thickness axial change curve set by the system. The current feedback signal is compared with the corresponding preset standard signal to obtain the current running result. When the feedback signal does not match the preset standard signal, it means that the running condition deviates from the parison wall thickness axial change curve, i.e. the current wall thickness condition does not conform to the preset wall thickness condition, and there is a deviation from the specified position. The feedback signal is compared with the preset standard signal to obtain the comparison result, i.e. the distance between the feedback signal and the preset standard signal, so as to adjust subsequently.

[0080] S32, when the feedback signal matches the preset standard signal, it means that the running condition follows the parison wall thickness axial change curve.

[0081] When the feedback signal matches the preset standard signal, it indicates that the current operation condition is in compliance with the axial variation curve of the parison wall thickness, that is, the plurality of parison control points correspond to the tracking of the plurality of set values on the axial variation curve of the parison wall thickness, and at this time, no comparison result is obtained, and the servo oil cylinder controls the center rod to continue operation and does not need to be adjusted.

[0082] When the feedback signal is compared with the preset standard signal, the operation condition is judged and the comparison result is obtained, and the following steps are performed:

[0083] S4, receiving monitoring signals of each part of the blow molding process, generating actual operation information and comparing with the preset monitoring range to obtain the comparison result.

[0084] In the blow molding process, each part is monitored to monitor the parison forming from multiple aspects. The monitoring signals include blow molding machine accumulator position monitoring signal, electro-hydraulic servo valve voltage and current fluctuation monitoring signal, and die temperature monitoring signal. In the blow molding process, the accumulator position in the blow molding machine, the voltage and current of the electro-hydraulic servo valve, and the die temperature are monitored.

[0085] Among them, the accumulator stores the hot-melt plastic, and the blow molding machine extrudes the hot-melt plastic into the accumulator. After the capacity of the accumulator reaches a certain position, the extrusion work is performed, and then the servo oil cylinder drives the center rod to move to change the gap of the die to change the wall thickness of the parison. Therefore, the position of the accumulator needs to be monitored during the blow molding process to quickly respond to the control of the parison wall thickness.

[0086] The voltage and current of the electro-hydraulic servo valve determine whether the center rod can be correctly controlled to move. The voltage and current of the electro-hydraulic servo valve are monitored to ensure the accuracy of the parison wall thickness control.

[0087] The temperature of the die affects the forming of the parison. The die temperature is monitored to ensure the forming of the parison so that the parison can be formed according to the preset forming time.

[0088] Therefore, the monitoring signals of each part of the blow molding process are received, and the actual operation information is generated and compared with the preset monitoring range to determine whether the current parison manufacturing process is correct, and the comparison result is obtained to adjust the actual operation information, referring to Figure 4 , the specific steps are as follows:

[0089] S41, the actual operation information includes blow molding machine accumulator position monitoring information, electro-hydraulic servo valve voltage and current fluctuation monitoring information, and die temperature monitoring information.

[0090] Specifically, the actual operation information includes blow molding machine accumulator position monitoring information, voltage and current fluctuation monitoring information of electro-hydraulic servo valve and die opening temperature monitoring information. The accumulator position monitoring is monitored by an electronic ruler, which is a position sensor that can sense the change of the accumulator position and convert it into a corresponding voltage signal. The voltage and current monitoring of the electro-hydraulic servo valve is to directly obtain the voltage and current signals of the current operation of the electro-hydraulic servo valve. The die opening temperature monitoring is monitored by a temperature sensor. The accumulator position monitoring information, voltage and current fluctuation monitoring information of electro-hydraulic servo valve and die opening temperature monitoring information are collectively collected into actual operation information and fed back to the system.

[0091] S42, when the actual operation information is in the preset monitoring range, it is explained that the actual operation information is normal operation.

[0092] The system receives the actual operation information and compares it with the preset monitoring range in the system. The preset monitoring range is the normal parameter range of each part of the parison wall thickness in the forming process. The preset monitoring range is configured in advance in the system. When the actual operation information is in the preset monitoring range, it means that the parameters of each part of the blow molding machine in the current parison forming process are in the normal range, and it also means that the actual operation information is normal operation. At this time, the comparison result is normal, and the actual operation information does not need to be adjusted.

[0093] S43, when the actual operation information is not in the preset monitoring range, it is explained that the actual operation information is abnormal operation.

[0094] When the actual operation information is not in the preset monitoring range, it means that there are some parts that are not in the normal range during the parison wall thickness forming process. Therefore, it is explained that the actual operation information is abnormal operation. At this time, the comparison result is obtained for the part not in the preset monitoring range. The distance between the part not in the preset monitoring range and the preset monitoring range is compared to obtain the comparison result, so as to adjust in time.

[0095] After obtaining the comparison result, the following steps are taken with reference to Figure 5 ,

[0096] S5, according to the comparison result and the comparison result, an adjustment signal is generated to adjust the blow molding process and the die opening position, so as to control the opening degree of the die opening and complete the dynamic closed loop adjustment of the parison wall thickness.

[0097] Specifically, the comparison result and the comparison result are jointly transmitted to the system. The system generates an adjustment signal according to the comparison result and the comparison result. The specific steps are as follows:

[0098] S51, the comparison result is adjusted based on the preset standard signal to generate a die opening position adjustment signal.

[0099] According to the comparison result and the preset standard signal as the reference, the feedback signal is taken as the reference of the preset standard signal, the deviation of the feedback signal and the preset standard signal is obtained, adjustment is made according to the deviation, the part to be adjusted is correspondingly generated to generate a mold port position adjustment signal, and the signal is sent to the electro-hydraulic servo valve, so that the electro-hydraulic servo valve controls the servo oil cylinder to drive the center rod to adjust.

[0100] S52, the comparison result is adjusted as the reference of the preset monitoring range to generate a parameter adjustment signal.

[0101] According to the comparison result and the preset monitoring range as the reference, the part not located in the preset monitoring range in the actual running information is taken as the reference of the corresponding preset monitoring range, and the numerical deviation of the actual running information and the preset monitoring range is obtained. The preset monitoring range is a numerical range, which has a maximum value and a minimum value. When the actual running information is greater than the maximum value, the numerical deviation obtained is the difference between the actual running information and the maximum value of the preset monitoring range. When the actual running information is less than the minimum value of the preset monitoring range, the numerical deviation obtained is the difference between the actual running information and the minimum value of the preset monitoring range. According to the data deviation of the actual running information and the preset monitoring range, a parameter adjustment signal is generated to adjust the part of the system that needs to be adjusted, so that the forming process of the parison wall thickness smoothly progresses.

[0102] The application also provides a full-closed-loop wall thickness control and contour following error detection control system, which refers to Figure 6 .

[0103] A full-closed-loop wall thickness control and contour following error detection control system, comprising:

[0104] An acquisition module 1 acquires user contour requirements and sets a parison wall thickness axial variation curve, and outputs a driving signal to an electro-hydraulic servo valve according to the parison wall thickness axial curve;

[0105] A control module 2 controls the electro-hydraulic servo valve according to the driving signal, so as to drive a servo oil cylinder to move the center rod of a blow molding machine up and down, and change the mold port gap of the blow molding machine head;

[0106] A comparison module 3 receives a feedback signal of an electronic ruler connected to the servo oil cylinder, and compares the feedback signal with a preset standard signal to judge the running condition and obtain a comparison result;

[0107] A comparison module 4 receives monitoring signals of each part of the blow molding process, generates actual running information, and compares the actual running information with a preset monitoring range to obtain a comparison result;

[0108] The adjusting module 5 generates an adjusting signal according to the comparison result and the comparison result to adjust each part of the blow molding process and the position of the die head die mouth, so as to control the opening degree of the die mouth and complete the dynamic closed loop adjustment of the parison wall thickness.

[0109] Firstly, the first acquiring module acquires the user's contour requirements and sets the parison wall thickness axial variation curve, and outputs a driving signal to the electro-hydraulic servo valve according to the parison wall thickness axial curve, and the control module 2 controls the electro-hydraulic servo valve to convert the driving signal into a mechanical displacement signal with a certain operating force, so that the servo oil cylinder drives the center rod of the blow molding machine to move to change the die head die mouth gap to control the parison wall thickness. Then, the comparison module 3 compares the feedback signal from the electronic ruler on the servo oil cylinder with the preset standard signal after receiving the feedback signal, judges the current running condition and obtains the comparison result, and then the comparison module 4 receives the monitoring signal of each part of the blow molding process and the actual production running information, and compares it with the preset monitoring range to obtain the comparison result. Finally, the adjusting module 5 generates an adjusting signal according to the comparison result and the comparison result to adjust each part of the blow molding process and adjust the electro-hydraulic servo valve to control the servo oil cylinder to adjust the position of the center rod, so as to control the parison wall thickness.

[0110] The embodiments of the specific embodiment are the preferred embodiments of the application, not limited to the protection scope of the application, wherein the same parts are indicated by the same reference numerals. Therefore: any equivalent changes made according to the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A full closed loop wall thickness control and profile following error detection control method, characterized by, The method comprises the following steps: Obtaining user profile requirements and setting a parison wall thickness axial variation curve, and outputting a driving signal to an electro-hydraulic servo valve according to the parison wall thickness axial curve; Controlling the electro-hydraulic servo valve according to the driving signal to drive the servo oil cylinder to move the blow molding machine center rod up and down, thereby changing the blow molding machine head die gap; Receiving a feedback signal of an electronic ruler connected to the servo oil cylinder and comparing it with a preset standard signal to determine the operation condition and obtain a comparison result; Receiving monitoring signals of each part of the blow molding process, generating actual operation information, and comparing it with a preset monitoring range to obtain a comparison result; Generating an adjustment signal according to the comparison result and the comparison result to adjust each part of the blow molding process and the head die position, thereby controlling the opening and closing degree of the die gap and completing the dynamic closed-loop adjustment of the parison wall thickness; The method for obtaining user profile requirements and setting a parison wall thickness axial variation curve comprises the following steps: Obtaining a plurality of parison control points according to the user profile requirements to generate user requirement parameters; Setting the parison wall thickness axial variation curve within a preset forming time through the user requirement parameters; A plurality of parison control points correspond to a plurality of set values on the parison wall thickness axial variation curve, and the parison control points correspond to the set values one by one, and the parison control points automatically track the set values. The driving signal is a corresponding voltage signal or current signal output according to the parison wall thickness axial curve.

2. The full closed loop wall thickness control and profile following error detection control method of claim 1, wherein, The feedback signal is a corresponding voltage signal generated after the electronic ruler senses the size of the head die gap.

3. The full closed loop wall thickness control and profile following error detection control method of claim 1, wherein, The monitoring signals include blow molding machine accumulator position monitoring signals, voltage and current fluctuation monitoring signals of the electro-hydraulic servo valve, and die temperature monitoring signals.

4. The full closed loop wall thickness control and profile following error detection control method of claim 1, wherein, Receiving a feedback signal of an electronic ruler connected to the servo oil cylinder and comparing it with a preset standard signal to determine the operation condition and obtain a comparison result comprises the following steps:

5. The full closed loop wall thickness control and profile following error detection control method of claim 1, wherein, When the feedback signal does not match the preset standard signal, it indicates that the operation condition deviates from the parison wall thickness axial variation curve, and the comparison result is the distance between the feedback signal and the preset standard signal; When the feedback signal matches the preset standard signal, it indicates that the operation condition follows the parison wall thickness axial variation curve. Receiving the monitoring signals of each part of the blow molding process and comparing them with a preset monitoring range to obtain a comparison result comprises the following steps:

6. The full closed loop wall thickness control and profile following error detection control method of claim 1, wherein, The actual operation information includes blow molding machine accumulator position monitoring information, voltage and current fluctuation monitoring information of the electro-hydraulic servo valve, and die temperature monitoring information; When the actual operation information is within the preset monitoring range, it indicates that the actual operation information is normal operation; When the actual operation information is not within the preset monitoring range, it indicates that the actual operation information is abnormal operation. The method for generating an adjustment signal according to the comparison result and the comparison result comprises the following steps:

7. The full closed loop wall thickness control and profile following error detection control method of claim 1, wherein, Adjusting the comparison result based on the preset standard signal to generate a die position adjustment signal; Adjusting the comparison result based on the preset monitoring range to generate a parameter adjustment signal. The method comprises the following steps:

8. A full closed loop wall thickness control and profile following error detection control system employing the full closed loop wall thickness control and profile following error detection control method of any one of claims 1-7, characterized by, ​ The acquisition module acquires the user profile requirement and sets the axial variation curve of the parison wall thickness, and outputs a driving signal to the electro-hydraulic servo valve according to the axial curve of the parison wall thickness; The control module controls the electro-hydraulic servo valve according to the driving signal, thereby driving the servo oil cylinder to move the center rod of the blow molding machine up and down, and changing the gap between the die head and the die mouth of the blow molding machine; The comparison module receives the feedback signal of the electronic ruler connected to the servo oil cylinder, and compares it with the preset standard signal to judge the operation condition and obtain the comparison result; The comparison module receives the monitoring signal of each part of the blow molding process, generates the actual operation information, and compares it with the preset monitoring range to obtain the comparison result; The adjustment module generates an adjustment signal according to the comparison result and the comparison result, adjusts each part of the blow molding process and the position of the die head die mouth, thereby controls the opening degree of the die mouth, and completes the dynamic closed loop adjustment of the parison wall thickness; The acquisition module acquires the user profile requirement and sets the axial variation curve of the parison wall thickness The acquisition module acquires the user profile requirement and sets the axial variation curve of the parison wall thickness The multiple parison control points correspond to multiple set values on the axial variation curve of the parison wall thickness, and the multiple parison control points correspond to the multiple set values one by one, and the parison control points automatically track the set values. ​ ​

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