Shear force control method and system for a plastic particle production plant

Abstract

The application relates to a shearing force control method and system of a plastic particle production device, and relates to the field of plastic granulation, and comprises the following steps: step 100: collecting a plastic strip image; step 101: identifying a plastic strip cross section from the plastic strip image; step 102: determining a cross section area in response to the plastic strip cross section; step 103: determining a deviation degree according to the cross section area; step 104: when the deviation degree exceeds a preset error interval, determining an adjustment coefficient in response to the deviation degree; step 105: determining a screw rotating speed according to the adjustment coefficient; and step 106: generating and sending a shearing control instruction in response to the screw rotating speed. The application has the effects of improving the stability of the plastic particle production device, intelligently regulating and controlling shearing force according to the thickness of the plastic strip, and improving the quality of the plastic particles.

Description

Technical Field

[0001] This invention relates to the field of plastic granulation, and in particular to a method and system for controlling shear force in plastic granulation equipment. Background Technology

[0002] Plastic pellet production equipment refers to mechanical equipment that processes plastic raw materials (virgin materials and recycled waste materials) into regular granular plastics through processes such as melting, mixing, extrusion, and pelletizing.

[0003] In existing technology, plastic pellet production equipment first melts plastic raw materials and uses a screw to shear the molten plastic to extrude it into continuous plastic strips. Then, a traction device drives the plastic strips to the cutter, and a cooling water tank is used to make the plastic strips harden quickly. Finally, the cutter rotates to cut the complete plastic strips into plastic pellets evenly.

[0004] The screw is prone to wear during use, which leads to insufficient shearing force, resulting in fluctuations in the diameter of the plastic strip and a reduction in the quality of the plastic granules. Summary of the Invention

[0005] To improve the stability of plastic granule production equipment, and to improve the quality of plastic granules by intelligently adjusting the shearing force according to the thickness of the plastic strip, this invention provides a shearing force control method and system for plastic granule production equipment.

[0006] In a first aspect, the present invention provides a method for controlling shear force in a plastic granule production equipment, employing the following technical solution:

[0007] A method for controlling shear force in a plastic pellet production equipment includes:

[0008] Step 100: Acquire an image of the plastic strip;

[0009] Step 101: Identify the cross-section of the plastic strip from the image of the plastic strip;

[0010] Step 102: Determine the cross-sectional area in response to the cross-section of the plastic strip;

[0011] Step 103: Determine the degree of deviation based on the cross-sectional area;

[0012] Step 104: When the deviation exceeds the preset error range, determine the adjustment coefficient in response to the deviation.

[0013] Step 105: Determine the screw speed according to the adjustment coefficient;

[0014] Step 106: In response to the screw speed generation, a shear control command is sent.

[0015] By adopting the above technical solution, visual technology is used to detect the cross-sectional area of ​​the plastic strip. When the deviation of the cross-sectional area is large, it is determined that the shearing force of the screw is insufficient. Then, an appropriate screw speed is selected to drive the screw to generate sufficient shearing force to form plastic strips that meet the specifications, thereby improving the stability of the plastic granule production equipment.

[0016] Optional, also includes:

[0017] Step 107: When the degree of deviation exceeds the preset error range, determine the deviation difference value based on the degree of deviation;

[0018] Step 108: Determine the response ratio based on the deviation difference;

[0019] Step 109: Determine the degree of wear in response to the response ratio;

[0020] Step 110: Determine the compensation coefficient based on the wear level;

[0021] Step 111: Update the screw speed based on the compensation coefficient.

[0022] By adopting the above technical solution, the cross-sectional area of ​​the plastic strip under the screw speed is detected by visual technology. The wear degree of the screw is predicted based on the change of the plastic strip cross-section, and the screw speed is then adjusted according to the wear degree. This reduces the situation of insufficient shear force caused by screw wear and improves the stability of the plastic granule production equipment.

[0023] Optional, also includes:

[0024] Step 112: When the compensation coefficient is greater than the preset adjustment threshold, determine the side cross section based on the plastic strip cross section;

[0025] Step 113: Determine the lateral area in response to the lateral cross section;

[0026] Step 114: Determine the degree of lateralization based on the lateralized area;

[0027] Step 115: Determine the degree ratio based on the degree of lateralization, and determine the shear defect according to the response ratio;

[0028] Step 116: Determine the lateral shearing based on the aforementioned degree ratio and shear defect;

[0029] Step 117: Determine the lateral shearing coefficient based on the lateral shearing and lateral degree;

[0030] Step 118: Update the screw speed based on the split coefficient.

[0031] By adopting the above technical solution, when the wear of the screw is large, the rotational speed required to compensate for the shear force is large. The cross-section of the plastic strip is divided into multiple sides according to the screw setting, and the wear of the screw in the corresponding direction is predicted according to the degree of division of the cross-sectional area of ​​different sides. In this way, the shear force of the screw with less wear is compensated by the screw with more wear, thereby reducing the rotational speed that needs to be adjusted and improving the stability of the plastic granule production equipment.

[0032] Optionally, it also includes a pelletizing control method, the pelletizing control method comprising:

[0033] Step 200: When the deviation exceeds the preset error range, determine the pelletizing force based on the cross-sectional area and the degree of deviation;

[0034] Step 201: Select the cutting speed based on the cutting force;

[0035] Step 202: Determine the traction speed in response to the cutter rotation speed;

[0036] Step 203: Generate and send a plastic pelletizing command by combining the traction speed and the cutter rotation speed.

[0037] By adopting the above technical solution, the hardness of plastic strips of different thicknesses varies. The minimum cutting force required to cut the plastic strips into pellets is predicted according to the size of the cross-sectional area. Thus, the appropriate cutting speed and traction speed are selected according to the cutting force, thereby reducing the situation where the cutting speed does not match the plastic strip, which leads to a decrease in the quality of plastic pellets and improving the quality of plastic pellets.

[0038] Optionally, the pelleting control method further includes:

[0039] Step 204: When the deviation exceeds the preset error range, the traction time is collected;

[0040] Step 205: Determine the traction force based on the traction speed and traction duration;

[0041] Step 206: Determine the lower limit of the area based on the traction force;

[0042] Step 207: If the cross-sectional area is less than the lower limit of the area, determine the intermittent duration by combining the lower limit of the area and the traction speed;

[0043] Step 208: Update the plastic pelletizing command in response to the interval duration.

[0044] By adopting the above technical solution, when it is necessary to increase the cutting speed to increase the shearing force, the traction speed needs to be increased simultaneously to ensure that the length of the plastic granules is uniform. This results in an increase in the traction force of the plastic strip. Based on the traction force, the lower limit of the area of ​​the plastic strip that is not stretched after being extruded from the screw is predicted. When the cross-sectional area is less than the lower limit, an appropriate interval is selected to stop traction of the plastic strip. This reduces the situation where the plastic strip is stretched or even broken due to excessive traction force, thereby improving the quality of the plastic granules.

[0045] Optionally, the pelleting control method further includes:

[0046] Step 209: When the interval duration is greater than the preset interval threshold, calculate the difference between the interval duration and the preset interval threshold, and define it as the compensation duration;

[0047] Step 210: Determine the compensation force based on the compensation duration and traction speed;

[0048] Step 211: Determine the spray volume based on the compensation force and cross-sectional area;

[0049] Step 212: In response to the generation of the sprayed water volume, a plastic hardening command is sent.

[0050] By adopting the above technical solution, when the interval is too long, the production efficiency of the plastic granule production equipment will be reduced. At this time, the compensation force required for the plastic strip to be unstretched is predicted according to the traction speed, and the appropriate amount of water sprayed is selected according to the compensation force to harden the plastic strip in advance, thereby reducing the situation where the plastic strip is stretched or even broken due to excessive traction force, and improving the quality of plastic granules.

[0051] Optionally, it also includes a plastic cooling method, said plastic cooling method comprising:

[0052] Step 300: If the cross-sectional area is not less than the lower limit of the area, determine the hardening time based on the cross-sectional area;

[0053] Step 301: Determine the immersion length in response to the hardening time and traction speed;

[0054] Step 302: Determine the adjustment length based on the immersion length;

[0055] Step 303: Determine the adjustment position based on the adjustment length;

[0056] Step 304: In response to the adjustment position and hardening duration, generate and send a cooling adjustment command.

[0057] By adopting the above technical solution, the hardening time required for the plastic strip to harden fully is predicted based on the cross-sectional area, and the immersion length of the plastic strip is determined according to the traction speed when it is just immersed in the cooling water tank for hardening time. Thus, the adjustment length required to adjust the plastic strip to the immersion length is selected, and the adjustment position of the pull ring device is selected according to the adjustment length so that the plastic strip can be pulled up or down from the cooling water tank by the pull ring device, thereby improving the quality of plastic granules.

[0058] Optionally, the plastic cooling method further includes:

[0059] Step 305: If the cross-sectional area is not less than the lower limit of the area, determine the speed difference based on the traction speed;

[0060] Step 306: Determine the length of influence by combining the speed difference and traction time;

[0061] Step 307: Determine the cooling length based on the influence length and adjustment length;

[0062] Step 308: Update the adjustment position in response to the cooling length.

[0063] By adopting the above technical solution, the total length change of the plastic strip is calculated according to the change of traction speed, and the adjustment length is corrected according to the total length change, thereby reducing the situation where the total length change of the plastic strip caused by the change of traction speed leads to inaccurate adjustment position.

[0064] Optionally, the plastic cooling method further includes:

[0065] Step 309: When the interval duration exceeds the preset interval threshold, determine the traction upper limit by combining the lower limit of the area and the preset interval threshold;

[0066] Step 310: Determine the upper limit of rotational speed based on the aforementioned upper limit of traction;

[0067] Step 311: Determine the upper limit of hardness by combining the upper limit of rotational speed and the cross-sectional area;

[0068] Step 312: Update the hardening time in response to the hardness limit and cross-sectional area.

[0069] By adopting the above technical solution, when the interval duration is too long, an appropriate traction upper limit is selected according to the interval duration to reduce the growth rate of traction force. Based on the traction upper limit, the upper limit of the rotation speed that the cutter can rotate is calculated. Then, based on the upper limit of the rotation speed, the upper limit of the hardness of the plastic strip that the cutter can cut is predicted. Based on the upper limit of the hardness, the cooling effect of the cooling water tank is reduced to soften the plastic strip, thereby improving the quality of plastic granules.

[0070] Secondly, this application provides a shear force control system for a plastic granule production equipment, which adopts the following technical solution:

[0071] A shear force control system for a plastic pellet production equipment includes:

[0072] The acquisition module is used to acquire images of plastic strips;

[0073] A memory for storing the program for the shear force control method of any of the above-mentioned plastic pellet production equipment;

[0074] The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0075] By adopting the above technical solution, visual technology is used to detect the cross-sectional area of ​​the plastic strip. When the deviation of the cross-sectional area is large, it is determined that the shearing force of the screw is insufficient. Then, an appropriate screw speed is selected to drive the screw to generate sufficient shearing force to form plastic strips that meet the specifications, thereby improving the stability of the plastic granule production equipment.

[0076] In summary, this application includes at least one of the following beneficial technical effects:

[0077] Visual technology is used to detect the cross-sectional area of ​​the plastic strip. When the deviation of the cross-sectional area is large, it can be determined that the shearing force of the screw is insufficient. Then, an appropriate screw speed is selected to drive the screw to generate sufficient shearing force to form plastic strips that meet the specifications, thereby improving the stability of the plastic granule production equipment.

[0078] By using visual technology to detect the cross-sectional area of ​​the plastic strip at different screw speeds, the wear level of the screw can be predicted based on the changes in the cross-sectional area of ​​the plastic strip. The screw speed can then be adjusted according to the wear level, thereby reducing the situation of insufficient shear force caused by screw wear and improving the stability of plastic granule production equipment.

[0079] When the wear of the screw is significant, the required increase in rotational speed to compensate for the shear force is also significant. The cross-section of the plastic strip is divided into multiple sides according to the screw configuration, and the wear of the screw in the corresponding direction is predicted based on the degree of division of the cross-sectional area of ​​different sides. In this way, the shear force lost by the screw with less wear can be compensated by the screw with more wear, thereby reducing the required adjustment speed of the screw and improving the stability of the plastic granule production equipment. Attached Figure Description

[0080] Figure 1 This is a flowchart of a shear force control method for a plastic pellet production equipment;

[0081] Figure 2 This is a flowchart of the pelletizing control method;

[0082] Figure 3This is a flowchart of a plastic cooling method. Detailed Implementation

[0083] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0084] Reference Figure 1 A method for controlling shear force in a plastic pellet production equipment, comprising:

[0085] Step 100: Acquire an image of the plastic strip.

[0086] Plastic strip images refer to continuous strips of plastic extruded through screw rotation. These images can be captured by a high-definition industrial camera installed at the extrusion die exit. The method for capturing these images is selected by the operator based on the actual situation and will not be elaborated here.

[0087] Step 101: Identify the cross-section of the plastic strip from the image of the plastic strip.

[0088] The cross-section of a plastic strip refers to the cross-sectional profile of a freshly extruded plastic strip. The cross-section of a plastic strip can be determined using image recognition technology. The method for identifying the cross-section of a plastic strip is common knowledge to those in the field and will not be elaborated here.

[0089] Step 102: Determine the cross-sectional area in response to the cross-section of the plastic strip.

[0090] The cross-sectional area refers to the total area of ​​the cross-section of a plastic strip. The cross-sectional area can be determined by image recognition technology. The method for determining the cross-sectional area is common knowledge in the field and will not be elaborated here.

[0091] Step 103: Determine the degree of deviation based on the cross-sectional area.

[0092] The degree of deviation refers to the numerical value used to show the diameter variation of the plastic strip. It can be calculated using the formula: Degree of deviation = (Cross-sectional area - Standard area) / Standard area. The standard area is preset by the staff based on the target particle size, which will not be elaborated here.

[0093] Step 104: When the deviation exceeds the preset error range, determine the adjustment coefficient in response to the deviation.

[0094] The error range refers to the allowable deviation range of the cross-sectional area. This range is set by staff based on product quality requirements and will not be elaborated upon here. A deviation exceeding the error range indicates a significant change in the diameter of the plastic strip, meaning insufficient shearing force from the screw. The adjustment coefficient is the proportional value used to adjust the screw speed to compensate for the insufficient shearing force. The further the deviation deviates from the error range, the larger the adjustment coefficient. The difference between the deviation and the error range can be calculated as the adjustment difference. Then, the corresponding adjustment coefficient for each deviation can be found in the adjustment correspondence table, which records different deviation levels and their corresponding adjustment coefficients.

[0095] Step 105: Determine the screw speed according to the adjustment coefficient.

[0096] Screw speed refers to the screw speed value after adjustment according to the adjustment coefficient. The screw speed can be calculated by multiplying the initial speed and the adjustment coefficient. The initial speed refers to the screw speed value before adjustment. The initial speed can be pre-input by the operator or read from the control system of the plastic granule production equipment. The method for determining the screw speed is pre-set by the operator according to the target granule size, which will not be elaborated here.

[0097] Step 106: In response to the screw speed generation, a shear control command is sent.

[0098] Shear control commands are commands that control the screw to rotate according to the screw speed. The method for generating shear control commands is common knowledge to those in the field and will not be elaborated here.

[0099] Visual technology is used to detect the cross-sectional area of ​​the plastic strip. When the deviation of the cross-sectional area is large, it can be determined that the shearing force of the screw is insufficient. Then, an appropriate screw speed is selected to drive the screw to generate sufficient shearing force to form plastic strips that meet the specifications, thereby improving the stability of the plastic granule production equipment.

[0100] A method for controlling shear force in a plastic pellet production equipment further includes:

[0101] Step 107: When the degree of deviation exceeds the preset error range, determine the deviation difference value according to the degree of deviation.

[0102] Deviation difference refers to the change in the degree of deviation, that is, the difference between the degree of deviation after adjustment and the degree of deviation before adjustment. After issuing the shear control command, the deviation degree can be updated as the degree of deviation after waiting for the response time. The response time refers to the minimum time required for the diameter of the plastic strip to stabilize after adjusting the speed. The response time is preset by the staff. The calculation method of deviation difference is selected by the staff according to the actual situation, which will not be elaborated here.

[0103] Step 108: Determine the response ratio based on the deviation difference.

[0104] The response ratio is a numerical value used to show the changes in the shear force of the screw. The larger the response ratio, the more the changes in the shear force of the screw are in line with expectations. The response ratio can be calculated as the quotient of the deviation difference and the adjustment difference.

[0105] Step 109: Determine the degree of wear in response to the response ratio.

[0106] Wear level refers to a numerical value used to show the wear condition of the screw. The larger the response ratio, the lighter the wear level. The wear level corresponding to the response ratio can be found in the wear correspondence table, which is a data table that records different response ratios and their corresponding wear levels.

[0107] Step 110: Determine the compensation coefficient based on the wear level.

[0108] The compensation coefficient refers to the proportional value of further adjusting the screw speed according to the degree of wear. Generally, the product of the compensation coefficient and the original screw speed is calculated as the new screw speed. The greater the degree of wear, the greater the compensation coefficient. The compensation coefficient corresponding to the degree of wear can be found in the compensation correspondence table, which is a data table that records different degrees of wear and their corresponding compensation coefficients.

[0109] Step 111: Update the screw speed based on the compensation coefficient.

[0110] By using visual technology to detect the cross-sectional area of ​​the plastic strip at different screw speeds, the wear level of the screw can be predicted based on the changes in the cross-sectional area of ​​the plastic strip. The screw speed can then be adjusted according to the wear level, thereby reducing insufficient shear force caused by screw wear and improving the stability of plastic granule production equipment.

[0111] A method for controlling shear force in a plastic pellet production equipment further includes:

[0112] Step 112: When the compensation coefficient is greater than the preset adjustment threshold, determine the side section based on the plastic strip cross section.

[0113] The adjustment threshold refers to the upper limit of the screw speed adjustment. The adjustment threshold is selected by the operator based on the actual situation and will not be elaborated here. A compensation coefficient greater than the adjustment threshold indicates that the screw speed variation is too large. The split section refers to the partial outline of the plastic strip cross-section after dividing it evenly according to the screw's orientation. For example, when the screws in a twin-screw plastic granule production equipment are symmetrically arranged, the plastic strip cross-section is divided into left and right parts from the center as the split section. The split section can be determined by image processing technology. The method for determining the split section is common knowledge in the field and will not be elaborated here.

[0114] Step 113: Determine the side area in response to the side section.

[0115] The lateral area refers to the area value of the lateral cross section. The lateral area can be determined by image recognition technology. The method for determining the lateral area is common knowledge in the field and will not be elaborated here.

[0116] Step 114: Determine the degree of lateralization based on the lateralized area.

[0117] The degree of deviation refers to the degree of deviation corresponding to the lateral cross section. The calculation method of the degree of deviation is the same as that of the deviation degree calculation method in step 103 above, and will not be repeated here.

[0118] Step 115: Determine the degree ratio based on the degree of lateralization, and determine the shear defect according to the response ratio.

[0119] The degree ratio refers to the proportion of shear force that the screws in different directions need to compensate for. The larger the absolute value of the degree of separation, the larger the degree ratio. The degree ratio can be calculated as the reciprocal of the ratio of the degree of separation. For example, in a twin-screw plastic granule production equipment, when the degree of separation of the left screw and the right screw is -0.2 and 0.3 respectively, the degree ratios of the left screw and the right screw are 0.6 and 0.4.

[0120] Shear defect refers to the magnitude of the shear force that needs to be compensated. The smaller the response ratio, the larger the shear defect. The shear defect corresponding to the response ratio can be found in the defect correspondence table, which is a data table that records different response ratios and their corresponding shear defects.

[0121] Step 116: Determine the lateral shearing based on the aforementioned degree ratio and shear defect.

[0122] Side shear refers to the magnitude of the shear force that the screw needs to compensate for in different directions. The degree ratio and the product of shear loss can be calculated as the side shear.

[0123] Step 117: Determine the lateral shearing coefficient based on the lateral shearing and lateral degree.

[0124] The shearing coefficient refers to the proportional value of the rotational speed that the screw needs to adjust to compensate for shearing in different directions. The greater the shearing and the greater the absolute value of the shearing degree, the greater the shearing coefficient. The shearing coefficient corresponding to the shearing and shearing degree can be found in the shearing correspondence table. The shearing correspondence table is a data table that records different shearing and shearing degrees and their corresponding shearing coefficients.

[0125] Step 118: Update the screw speed based on the split coefficient.

[0126] When the wear of the screw is significant, the required increase in rotational speed to compensate for the shear force is also significant. The cross-section of the plastic strip is divided into multiple sides according to the screw configuration, and the wear of the screw in the corresponding direction is predicted based on the degree of division of the cross-sectional area of ​​different sides. In this way, the shear force lost by the screw with less wear can be compensated by the screw with more wear, thereby reducing the required adjustment speed of the screw and improving the stability of the plastic granule production equipment.

[0127] Reference Figure 2 Pelletizing control methods include:

[0128] Step 200: When the deviation exceeds the preset error range, determine the pelletizing force based on the cross-sectional area and the deviation.

[0129] Pelletizing force refers to the minimum shearing force required to cut a plastic strip. When the deviation is greater than 0, it means that the plastic strip has expanded, and the density of the plastic strip has decreased, requiring a smaller pelletizing force. When the deviation is not greater than 0, it means that the plastic melt has not been fully cut, and the plastic strip is harder, requiring a larger pelletizing force. The pelletizing force corresponding to the cross-sectional area and the deviation can be found in the pelletizing correspondence table, which is a data table that records different cross-sectional areas, deviations and their corresponding pelletizing forces.

[0130] Step 201: Select the cutting speed based on the cutting force.

[0131] The cutting speed refers to the minimum rotational speed required for the pelletizing device to generate cutting force. The pelletizing device is a device used to cut plastic strips to obtain uniform plastic granules. The pelletizing device is selected by the operator according to the actual situation. The cutting speed corresponding to the cutting force can be found in the speed correspondence table. The speed correspondence table is a data table that records different cutting forces and their corresponding cutting speeds.

[0132] Step 202: Determine the traction speed in response to the cutter rotation speed.

[0133] Traction speed refers to the speed at which the traction device drives the plastic strip toward the cutter. The traction device is the roller that drives the plastic strip to move in a specific direction. The traction device is selected by the operator according to the actual situation. In order to ensure that the length of the manufactured plastic granules is consistent, the traction speed needs to change synchronously with the cutter speed. That is, the higher the cutter speed, the higher the traction speed. The traction speed corresponding to the cutter speed can be found in the speed correspondence table. The speed correspondence table is a data table that records different cutter speeds and their corresponding traction speeds.

[0134] Step 203: Generate and send a plastic pelletizing command by combining the traction speed and the cutter rotation speed.

[0135] Plastic pelletizing instructions are commands that control the pelletizing device and traction device to operate according to corresponding parameters. The method of generating plastic pelletizing instructions is common knowledge to those skilled in the art and will not be elaborated here.

[0136] Different thicknesses of plastic strips have different hardness. The minimum cutting force required to cut the plastic strips into pellets is predicted according to the size of the cross-sectional area. Then, the appropriate cutting speed and traction speed are selected according to the cutting force, thereby reducing the situation where the cutting speed does not match the plastic strip, which leads to a decrease in the quality of plastic pellets and improving the quality of plastic pellets.

[0137] Pelletizing control methods also include:

[0138] Step 204: When the deviation exceeds the preset error range, collect the traction time.

[0139] Traction duration refers to the duration of operation of the traction device. Traction duration can be collected by a timer. The method for collecting traction duration is selected by the staff according to the actual situation, and will not be elaborated here.

[0140] Step 205: Determine the traction force by combining the traction speed and traction duration.

[0141] Traction force refers to the tensile force on the plastic strip under the action of the traction device. The greater the traction speed and traction duration, the greater the traction force. The traction force corresponding to the traction speed and traction duration can be found in the force correspondence table, which is a data table that records different traction speeds and traction durations and their corresponding traction forces.

[0142] Step 206: Determine the lower limit of the area based on the traction force.

[0143] The lower limit of area refers to the minimum cross-sectional area that is not easily stretched and deformed under traction force. The greater the traction force, the larger the lower limit of area. The lower limit of area corresponding to the traction force can be found in the tension correspondence table, which is a data table that records different traction forces and their corresponding lower limits of area.

[0144] Step 207: If the cross-sectional area is less than the lower limit of the area, determine the intermittent duration by combining the lower limit of the area and the traction speed.

[0145] A cross-sectional area smaller than the lower limit of the area indicates that the plastic strip is difficult to withstand the traction force, meaning that the plastic strip is easily stretched. The interval duration refers to the duration for which the traction device stops traction. The larger the lower limit of the area and the traction speed, the longer the interval duration should be. The interval duration corresponding to the lower limit of the area and the traction speed can be found in the interval correspondence table. The interval correspondence table is a data table that records different lower limits of the area and traction speeds and their corresponding interval durations.

[0146] Step 208: Update the plastic pelletizing command in response to the interval duration.

[0147] When it is necessary to increase the cutter speed to increase the shearing force, the traction speed needs to be increased simultaneously to ensure the uniform length of the plastic granules. This results in an increase in the traction force of the plastic strip. Based on the traction force, the lower limit of the area of ​​the plastic strip that is not stretched after being extruded from the screw is predicted. When the cross-sectional area is less than the lower limit, an appropriate interval is selected to stop traction of the plastic strip. This reduces the situation where the plastic strip is stretched or even broken due to excessive traction force, thereby improving the quality of the plastic granules.

[0148] Pelletizing control methods also include:

[0149] Step 209: When the interval duration is greater than the preset interval threshold, calculate the difference between the interval duration and the preset interval threshold, and define it as the compensation duration.

[0150] The intermittent threshold refers to the maximum allowable continuous intermittent duration. This threshold is set by staff based on production efficiency requirements and will not be elaborated upon here. An intermittent duration exceeding the intermittent threshold indicates that the traction stop time is too long. The compensation duration refers to the intermittent duration exceeding the intermittent threshold, and it reflects the tensile force the plastic strip needs to withstand.

[0151] Step 210: Determine the compensation force by combining the compensation duration and traction speed.

[0152] The compensation force refers to the increased traction force of the plastic strip under the compensation duration. The compensation force corresponding to the compensation duration and traction speed can be found in the force correspondence table.

[0153] Step 211: Determine the spray volume based on the compensation force and cross-sectional area.

[0154] The cooling water tank is a device used to harden plastic strips. It is located between the pelletizing device and the extrusion die outlet. The cooling water tank contains circulating coolant. The selection of the cooling water tank is made by the staff according to the actual situation, and will not be elaborated here.

[0155] The spraying device is a device used to spray the coolant in the cooling water tank onto the freshly extruded plastic strip to harden the plastic strip. The spraying device is installed on the side of the cooling water tank near the outlet of the extrusion die. The spraying device is selected by the staff according to the actual situation, and will not be described in detail here.

[0156] The spray volume refers to the volume of coolant that needs to be sprayed per unit time through the hardened plastic strip of the spraying device. The larger the compensation force and cross-sectional area, the larger the spray volume is. The spray volume corresponding to the compensation force and cross-sectional area can be found in the spray correspondence table. The spray correspondence table is a data table that records different compensation forces and cross-sectional areas and their corresponding spray volumes.

[0157] Step 212: In response to the generation of the sprayed water volume, a plastic hardening command is sent.

[0158] Plastic hardening instructions are commands that control the spraying device to spray according to the amount of water to be sprayed. The method for generating plastic hardening instructions is common knowledge to those in the field and will not be elaborated here.

[0159] When the interval is too long, it can easily lead to a decrease in the production efficiency of plastic granule production equipment. In this case, the compensation force required for the plastic strip to be prevented from being stretched is predicted according to the traction speed, and an appropriate amount of water is sprayed to harden the plastic strip in advance based on the compensation force. This reduces the situation where the plastic strip is stretched or even broken due to excessive traction force, thereby improving the quality of plastic granules.

[0160] Reference Figure 3 Plastic cooling methods include:

[0161] Step 300: If the cross-sectional area is not less than the lower limit of the area, determine the hardening time based on the cross-sectional area.

[0162] A cross-sectional area not less than the lower limit indicates that the plastic strip can withstand the tension applied by the traction device. The hardening time refers to the minimum time required to fully harden the plastic strip of the cross-sectional area. The larger the cross-sectional area, the longer the hardening time. The hardening time corresponding to the cross-sectional area can be found in the hardening correspondence table.

[0163] Step 301: Determine the immersion length in response to the hardening time and traction speed.

[0164] Immersion length refers to the total length of the plastic strip submerged in the cooling water tank when it is just submerged in the hardening time. It is calculated as the product of the hardening time and the traction speed.

[0165] Step 302: Determine the adjustment length based on the immersion length.

[0166] The adjustment length refers to the amount of change required to adjust the length of the submerged plastic strip, which is calculated as the difference between the immersion length and the initial length. The initial length refers to the length of the plastic strip submerged in the cooling water tank at this time, and the initial length can be preset by the staff.

[0167] Step 303: Determine the adjustment position based on the adjustment length.

[0168] The pull ring device is a device used to adjust the immersion length. The pull ring device includes a pull ring for carrying the plastic strip and a roller for adjusting the position. The pull ring device can move along the extension direction of the plastic strip. The cooling water tank is equipped with a slide rail for the roller to move. The pull ring device is located between the outlet point of the plastic strip leaving the coolant and the pelletizing device. The pull ring device is selected by the staff according to the actual situation, and will not be described in detail here.

[0169] The adjustment position refers to the position where the plastic strip carried by the adjustment ring device is adjusted so that the length of the plastic strip immersed in the coolant is exactly equal to the immersion length. The larger the adjustment length, the farther the adjustment position is from the pelletizing device. The adjustment position corresponding to the adjustment length can be found in the position correspondence table, which is a data table that records different adjustment lengths and their corresponding adjustment positions.

[0170] Step 304: In response to the adjustment position and hardening duration, generate and send a cooling adjustment command.

[0171] The cooling adjustment command is a command that controls the pull ring device to move sequentially according to the adjustment position in the order of hardening time. The method of generating the cooling adjustment command is common knowledge to those skilled in the art and will not be described in detail here.

[0172] The curing time required for the plastic strip to fully harden is predicted based on the cross-sectional area. The immersion length of the plastic strip when it is just immersed in the cooling water tank for the curing time is determined according to the traction speed. The adjustment length required to adjust the plastic strip to the immersion length is then selected. The adjustment position of the pull ring device is selected according to the adjustment length so that the plastic strip can be pulled up or down from the cooling water tank by the pull ring device, thereby improving the quality of the plastic granules.

[0173] Plastic cooling methods also include:

[0174] Step 305: If the cross-sectional area is not less than the lower limit of the area, determine the speed difference based on the traction speed.

[0175] Speed ​​difference refers to the difference between the production and consumption speeds of plastic strips. It is calculated as the difference between the production speed and the traction speed. The production speed refers to the length of the plastic strip produced at the extrusion die outlet per unit time. The production speed is preset by the staff.

[0176] Step 306: Determine the length of influence by combining the speed difference and traction time.

[0177] The influence length refers to the change in the total length of the plastic strip during the traction time. It can be calculated as the product of the speed difference and the traction time.

[0178] Step 307: Determine the cooling length based on the influence length and adjustment length.

[0179] Cooling length refers to the amount of adjustment required to adjust the length of the submerged plastic strip at the traction speed; that is, the sum of the influencing length and the adjusting length is calculated as the cooling length.

[0180] Step 308: Update the adjustment position in response to the cooling length.

[0181] The total length change of the plastic strip is calculated based on the change in traction speed. The adjustment length is then corrected according to the total length change, thereby reducing the possibility of inaccurate adjustment position caused by changes in the total length of the plastic strip due to changes in traction speed.

[0182] Plastic cooling methods also include:

[0183] Step 309: When the interval duration is greater than the preset interval threshold, the traction upper limit is determined by combining the lower limit of the area and the preset interval threshold.

[0184] The traction limit refers to the maximum traction speed that the plastic strip with the lower area limit can withstand. The smaller the lower area limit and the larger the intermittent threshold, the larger the traction limit should be. The traction limit corresponding to the lower area limit and the intermittent threshold can be found in the intermittent correspondence table.

[0185] Step 310: Determine the upper limit of rotational speed based on the upper limit of traction.

[0186] The upper limit of rotational speed refers to the cutter rotational speed corresponding to the upper limit of traction. The upper limit of rotational speed corresponding to the upper limit of traction can be found in the speed correspondence table.

[0187] Step 311: Determine the upper limit of hardness by combining the upper limit of rotational speed and the cross-sectional area.

[0188] The upper limit of hardness refers to the maximum hardness of the plastic strip that the cutter can cut at the maximum speed. The higher the upper limit of speed and the smaller the cross-sectional area, the higher the upper limit of hardness. The upper limit of hardness corresponding to the upper limit of speed and cross-sectional area can be found in the hardness correspondence table. The hardness correspondence table is a data table that records different upper limits of speed and cross-sectional areas and their corresponding upper limits of hardness.

[0189] Step 312: Update the hardening time in response to the hardness limit and cross-sectional area.

[0190] When the interval is too long, a suitable upper limit of traction is selected according to the interval to reduce the growth rate of traction force. Based on the upper limit of traction, the upper limit of the rotation speed that the cutter can rotate is calculated. Then, based on the upper limit of rotation speed, the upper limit of the hardness of the plastic strip that the cutter can cut is predicted. Based on the upper limit of hardness, the cooling effect of the cooling water tank is reduced to soften the plastic strip, thereby improving the quality of plastic granules.

[0191] Based on the same inventive concept, embodiments of the present invention provide a shear force control system for a plastic granule production equipment, comprising:

[0192] The acquisition module is used to acquire images of plastic strips;

[0193] A memory for storing the program for the shear force control method of any of the above-mentioned plastic pellet production equipment;

[0194] The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0195] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0196] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A shear force control method for a plastic particle production apparatus, characterized by, The method comprises: Step 100: collecting a plastic strip image; Step 101: identifying a plastic strip cross section from the plastic strip image; Step 102: determining a cross section area in response to the plastic strip cross section; Step 103: determining a deviation degree in accordance with the cross section area, the deviation degree being a numerical value for showing a diameter variation of the plastic strip; Step 104: determining an adjustment coefficient in response to the deviation degree when the deviation degree exceeds a preset error interval, the adjustment coefficient being a proportional value for adjusting a rotation speed of a screw to compensate for a shear force of a defect; Step 105: determining a screw rotation speed in accordance with the adjustment coefficient; Step 106: generating and sending a shear control instruction in response to the screw rotation speed; The method further comprises: Step 107: determining a deviation difference in accordance with the deviation degree when the deviation degree exceeds the preset error interval, the deviation difference being a variation value of the deviation degree, i.e. a difference between the adjusted deviation degree and the unadjusted deviation degree; Step 108: determining a response proportion based on the deviation difference, the response proportion being a numerical value for showing a shear force variation of the screw, the greater the response proportion, the more the shear force variation of the screw meets an expectation; Step 109: determining a wear degree in response to the response proportion, the wear degree being a numerical value for showing a wear condition of the screw; Step 110: determining a compensation coefficient in accordance with the wear degree, the compensation coefficient being a proportional value for further adjusting the rotation speed of the screw according to the wear degree; Step 111: updating the rotation speed of the screw based on the compensation coefficient.

2. The shear force control method of a plastic particle production apparatus according to claim 1, characterized by, The method further comprises: Step 112: determining a split side cross section based on the plastic strip cross section when the compensation coefficient is greater than a preset adjustment threshold; Step 113: determining a split side area in response to the split side cross section; Step 114: determining a split side degree in accordance with the split side area; Step 115: determining a degree proportion based on the split side degree, and determining a shear defect in accordance with the response proportion; Step 116: determining a split side shear in combination with the degree proportion and the shear defect; Step 117: determining a split side coefficient in accordance with the split side shear and the split side degree; Step 118: updating the rotation speed of the screw based on the split side coefficient.

3. The shear force control method of a plastic particle production apparatus according to claim 2, characterized by, The method further comprises a pelletizing control method, which comprises: Step 200: determining a pelletizing intensity in accordance with the cross section area and the deviation degree when the deviation degree exceeds the preset error interval; Step 201: selecting a cutter rotation speed based on the pelletizing intensity; Step 202: determining a traction speed in response to the cutter rotation speed; Step 203: generating and sending a plastic pellet instruction in combination with the traction speed and the cutter rotation speed.

4. The shear force control method of a plastic particle production apparatus according to claim 3, characterized by, The pelletizing control method further comprises: Step 204: collecting a traction duration when the deviation degree exceeds the preset error interval; Step 205: determining a traction intensity in combination with the traction speed and the traction duration; Step 206: determining a lower limit of the area in accordance with the traction intensity; Step 207: determining an intermittent duration in combination with the lower limit of the area and the traction speed if the cross section area is less than the lower limit of the area; Step 208: updating the plastic pellet instruction in response to the intermittent duration.

5. The shear force control method of a plastic particle production apparatus according to claim 4, characterized by, The pelletizing control method further comprises: Step 209: When the intermittent duration is greater than the preset intermittent threshold, calculate the difference between the intermittent duration and the preset intermittent threshold, and define as a compensation duration; Step 210: Determine the compensation intensity in combination with the compensation duration and the traction speed; Step 211: Determine the spraying water volume according to the compensation intensity and the cross-sectional area; Step 212: Generate and send a plastic hardening instruction in response to the spraying water volume.

6. The shear force control method of a plastic particle production apparatus according to claim 5, characterized by, Also included is a plastic cooling method, the plastic cooling method comprising: Step 300: If the cross-sectional area is not less than the area lower limit, determine the hardening duration according to the cross-sectional area; Step 301: Determine the immersion length in response to the hardening duration and the traction speed; Step 302: Determine the adjustment length based on the immersion length; Step 303: Determine the adjustment position according to the adjustment length; Step 304: Generate and send a cooling adjustment instruction in response to the adjustment position and the hardening duration.

7. The shear force control method of a plastic particle production apparatus according to claim 6, characterized by, The plastic cooling method further comprises: Step 305: If the cross-sectional area is not less than the area lower limit, determine the speed difference value based on the traction speed; Step 306: Determine the influence length in combination with the speed difference value and the traction duration; Step 307: Determine the cooling length according to the influence length and the adjustment length; Step 308: Update the adjustment position in response to the cooling length.

8. The shear force control method of a plastic particle production apparatus according to claim 7, characterized by, The plastic cooling method further comprises: Step 309: When the intermittent duration is greater than the preset intermittent threshold, determine the traction upper limit in combination with the area lower limit and the preset intermittent threshold; Step 310: Determine the rotational speed upper limit according to the traction upper limit; Step 311: Determine the hardness upper limit in combination with the rotational speed upper limit and the cross-sectional area; Step 312: Update the hardening duration in response to the hardness upper limit and the cross-sectional area.

9. A shear force control system of a plastic particle production apparatus, characterized by, Comprise: An acquisition module for acquiring a plastic strip image; A memory for storing a program of a shear force control method of a plastic particle production equipment according to any one of claims 1 to 8; A processor, the program in the memory can be loaded and executed by the processor.

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