CN-121980783-A - Cooling valve position correction method based on micro-strategy optimization

CN121980783ACN 121980783 ACN121980783 ACN 121980783ACN-121980783-A

Abstract

The invention provides a cooling valve position correction method based on micro-strategy optimization, which aims at an assembly standard Kong Piancha of a rib plate workpiece caused by crystallization and anisotropic shrinkage, under the condition of not changing a mould and a gate, collects three-stage valve position opening and water inlet and outlet temperature, builds a thermal structure model of coupling heat-crystallization-anisotropic shrinkage, converts a valve position into three-stage mould wall heat radiation intensity, sets a hole periphery control area and predicts hole position deviation, distributes and adjusts opening of each cooling loop according to three stages in process constraint based on an equivalent force field and an influence coefficient, disperses into a valve minimum adjustment step, combines actual measurement closed loop iteration until the deviation threshold is met, and realizes the prediction of the mould pressing performance of a thermoplastic composite material and the positive regulation of the hole position, thereby improving the consistency of the hole position and the process executable.

Inventors

CHEN YIWEI
FAN CONGZE
ZHU SHU
SONG WENZHE
ZHENG JINGHUA
GAO YU

Assignees

南京航空航天大学
东华大学

Dates

Publication Date: 20260505
Application Date: 20260114

Claims (9)

1. A method for cooling valve position correction based on micro-strategy optimization, comprising: S1, in the in-mold cooling of a thermoplastic composite rib plate, acquiring valve position opening and water inlet and outlet temperatures of a cooling loop, establishing an assembly reference frame, calculating a reference Kong Piancha, and determining the upper limit and the lower limit of the opening, the total cooling capacity, the opening change rate and the deviation threshold value under the condition that a mold and a gate are not changed to form a process constraint and hole site deviation target; S2, constructing a thermal structure warping model for coupling crystallization and anisotropic shrinkage and fixing a material orientation field according to valve position opening, water temperature, an assembly reference frame, process constraint and a hole position deviation target, setting a hole periphery control area, representing the hole position deviation by using area center displacement, converting the valve position opening into the mold wall heat radiation intensity of three stages of pressure maintaining, primary cooling and final cooling, accounting in the influence of loop shunting, calculating the temperature, deformation results and hole position deviation prediction, and obtaining a valve position conversion relation; s3, predicting a reverse thrust equivalent force field from the hole position deviation based on the temperature and deformation result, the hole circumference control area and the valve position conversion relation, calculating the influence coefficient of the hole position deviation on three stages of each loop, adjusting the opening of each loop in stages according to the influence coefficient and limiting the change amplitude under the process constraint to form a valve position updating curve, so that the prediction deviation is reduced according to the target direction; s4, dispersing according to a valve position updating curve and a valve position conversion relation and performing equipment realizability judgment according to a minimum adjusting step distance of a valve to form an executable valve position instruction; s5, performing trial production according to the executable valve position instruction, measuring the coordinates of the reference hole and aligning with the assembly reference frame, and calculating the actual measurement hole position deviation; s6, judging the actually measured hole position deviation according to the deviation threshold, forming a final valve position setting when the deviation threshold is met, and correcting a valve position updating curve by combining the influence coefficient in the process constraint when the deviation threshold is not met, and forming a secondary valve position setting.
2. The cooling valve position correction method based on micro-strategy optimization according to claim 1, wherein S1 is specifically: In the in-mold cooling of the thermoplastic composite rib plate, the valve position opening and water inlet and outlet temperatures are obtained by a cooling loop one by one, the valve position opening is given according to three stages of pressure maintaining, primary cooling and final cooling, and one-to-one identification is kept with the corresponding cooling loop; Constructing an assembly reference frame by three-dimensional translation and three-dimensional rotation angles, aligning the coordinates of the actually measured reference holes to the assembly reference frame, and calculating three reference hole deviation; Under the condition of not changing the mould and the pouring gate, determining the upper limit, the lower limit and the opening change rate range of each cooling loop according to the cooling system and the equipment capacity, forming process constraint by combining the total cooling capacity and the deviation threshold value, and determining a hole position deviation target according to the process constraint; And organizing the valve position opening, the water inlet and outlet temperature, the assembly reference frame, the reference hole deviation and the process constraint into an input set of a thermal structure warping model for coupling crystallization and anisotropic contraction, and establishing a corresponding relation between a cooling loop and a boundary section for construction of a follow-up valve position conversion relation.
3. The cooling valve position correction method based on micro-strategy optimization according to claim 1, wherein S2 is specifically: taking valve position opening, water temperature, assembly reference frame, process constraint and hole position deviation targets as inputs, establishing one-to-one correspondence between boundary sections and cooling loops according to three-dimensional grids and boundary areas of parts and cooling pipelines, and initializing materials and geometric constant channels for subsequent transmission; Writing a fixed material orientation field into a point-by-point mapping layer of a shrinkage branch according to a three-dimensional grid, taking three-dimensional orientation values of each grid node as constant channels, designating not to participate in valve position opening adjustment and keeping stability under the condition of not changing a mould and a gate; Setting a hole periphery control area around a reference hole, defining the center of the area and aligning with an assembly reference frame, and taking three areas of area center displacement as reading amounts of hole position deviation targets and as evaluation inlets of subsequent temperature and deformation results; In a valve position conversion layer, mapping valve position opening of each cooling loop in pressure maintaining, primary cooling and final cooling and corresponding water temperature to each boundary section according to pipeline resistance and shunt parameters, generating three sections of die wall heat dissipation intensity channels, accounting for loop shunt influence, and limiting heat dissipation intensity within the upper and lower opening limits and total cooling capacity through door control; In a grid transfer layer of the thermal branch, a three-dimensional grid is transferred based on three sections of mold wall heat dissipation intensity channels and water temperature, three channels of a temperature field are output, and the energy balance and grid adjacency relation is corrected through a conservation constraint projection unit, so that a temperature time sequence for contracting the branch is obtained; In a point-by-point mapping layer of the shrinkage branch, calculating crystallinity and a three-way shrinkage channel according to a temperature time sequence of each node and a fixed material orientation field, in a mechanical transmission layer of the structural branch, carrying out mechanical transmission on three-way shrinkage and temperature field input, outputting six channels of stress and three channels of displacement, and meeting the continuous constraint and displacement of a die through a constraint projection layer; and in the hole position reading layer, carrying out volume weighted summarization on three displacement channels in the hole periphery control area, completing alignment according to the assembly reference frame to obtain three hole position deviation prediction items, and correspondingly solidifying time segments between the valve position opening and the heat radiation intensity of the three sections of mold walls into a valve position conversion relation for subsequent influence coefficient calculation and adjustment in process constraint.
4. A cooling valve position correction method based on micro-strategy optimization according to claim 3, wherein the valve position conversion relation is calculated by adopting a valve position conversion formula: ; Wherein, the Represent the first The boundary sections are in phase Is arranged on the die wall of the die, the heat dissipation strength of the die wall of the die is improved, Represent the first The area of the individual boundary sections is determined, Indicating the number of cooling circuits and, Mapping function representing correspondence Is used to indicate the amount of discrete indication of (c), Represent the first Belonging to the boundary section The strip cooling circuit comprises a strip cooling circuit, Indicating that the device is not to be attributed, Represent the first Strip cooling loop to the first The shunt weight of each boundary section is determined by the shunt and pressure drop relationship of the parallel pipeline, Represent the first Nominal mass flow of the cooling circuit at full range of valve opening, Represent the first The strip cooling circuit is in phase Is provided with a valve position opening degree, Represents the constant pressure specific heat of the cooling medium, Represent the first The water inlet temperature of the strip cooling loop, Represent the first Water outlet temperature of strip cooling loop, gate control unit pair Is limited by the result of (2) Converted into Meets the upper and lower limits of opening degree, upper limit of total cooling capacity and upper limit of opening degree change rate at each stage, and maintains the same Is consistent with the routing of (a).
5. The cooling valve position correction method based on micro-strategy optimization according to claim 1, wherein S3 is specifically: Taking temperature and deformation results, a hole periphery control area, a valve position conversion relation and hole position deviation prediction as inputs, taking three hole position deviation prediction items as back-pushing constraint quantities in a thermal structure warping model, and determining displacement requirements of the hole periphery control area; Reversely pushing out an equivalent force field in the thermal structure warping model according to displacement requirements, so that the displacement of a hole periphery control area reproduces hole position deviation prediction under the condition that a mold and a gate are not changed, and the orientation field of a fixed material and the constraint of the mold are kept unchanged; Calculating an influence coefficient according to the equivalent force field and valve position conversion relation and according to pressure maintaining, initial cooling and final cooling three-stage gradual cooling loops, wherein the influence coefficient represents the proportion of the change of the opening of a single loop to the predicted change of the hole position deviation at a certain stage under the condition that the orientation field of a fixed material and the technological constraint are unchanged; according to the influence coefficient and the hole position deviation target direction, calculating the opening adjustment quantity of each cooling loop in stages under the process constraint, limiting the change amplitude of each time and meeting the requirements of the upper limit and the lower limit of the opening, the total cooling capacity and the opening change rate, and forming a staged adjustment sequence; Mapping the opening adjustment quantity of each cooling loop in three stages into three sections of mold wall heat dissipation intensity changes through valve position conversion relation, synthesizing an initial valve position updating curve, and keeping corresponding and consistent time segments of the valve position opening and the mold wall heat dissipation intensity; inputting an initial valve position updating curve into a thermal structure warping model, calculating updated temperature and deformation results and hole position deviation prediction, carrying out volume weighted comparison on three displacement items in a hole periphery control area, and judging whether the prediction deviation is reduced along the target direction of the hole position deviation; And when judging that the deviation of the hole position is not reduced along the target direction of the hole position deviation, correcting the sequence and the amplitude of the three-stage opening adjustment quantity based on the influence coefficient in the process constraint, updating the valve position update curve, and predicting again to reduce the prediction deviation along the target direction of the hole position deviation.
6. The cooling valve position correction method based on micro-strategy optimization according to claim 4, wherein when the influence coefficient is calculated according to the equivalent force field and valve position conversion relation and according to pressure maintaining, initial cooling and final cooling three-stage cooling loops, a mapping formula is adopted for calculating the influence coefficient: ; ; Wherein, the Represent the first The strip cooling circuit is in phase Prediction of hole position deviation The coefficient of influence of the component(s), Indicating that the position deviation is predicted at the first position Readout function on component whose value is determined by thermal structure warping model Is obtained after the alignment of the volume weighting and the assembly reference frame, Represent the first The strip cooling circuit is in phase Is provided with a valve position opening degree, Represent the first The strip cooling circuit is in phase Is a trial increment of the minimum executable opening of (c), Index for the coordinate component 、、 Three components, only adjusted in heuristic calculations And pass through Will be The heat dissipation intensity change of the three-section mold wall mapped to the corresponding boundary section is finally read out And the ratio calculation is completed.
7. The cooling valve position correction method based on micro-strategy optimization according to claim 1, wherein S4 is specifically: Taking the valve position updating curve and the valve position conversion relation as input, reading a target opening sequence according to each cooling loop of pressure maintaining, primary cooling and final cooling, and keeping the target opening sequence corresponding to the time segments of each boundary section; Discretizing a target opening sequence according to the minimum valve regulating step, rounding the opening to be an integral multiple of the minimum valve regulating step for each cooling loop according to each stage, and keeping the opening within the upper limit and the lower limit of the opening; in the equipment realizability judgment, checking whether the opening degree after discrete loop-by-loop and stage-by-stage meets the process constraint of the total cooling capacity, the upper limit and the lower limit of the opening degree and the opening degree change rate, and keeping the time segment correspondence of the heat dissipation intensity of the three sections of mold walls consistent under the valve position conversion relation; And (3) carrying out amplitude correction on the opening which does not meet the process constraint along the target direction on the premise of not changing the valve position conversion relation, selecting the nearest opening which meets the minimum regulation step of the valve and the process constraint, and generating an executable valve position instruction according to the cooling loop and the three stages.
8. The cooling valve position correction method based on micro-strategy optimization according to claim 1, wherein S5 is specifically: Loading executable valve position instructions to a cooling system, and executing opening of each cooling loop according to the minimum valve adjusting step in three stages of pressure maintaining, primary cooling and final cooling to finish in-mold cooling trial production of the thermoplastic composite rib plate; measuring the reference hole after demolding, acquiring three reference hole coordinates according to a measurement reference defined by an assembly reference frame, and avoiding generating additional load on a workpiece in the measurement process; Aligning the coordinates of the reference holes by taking the assembly reference frame as a reference, establishing a one-to-one correspondence between the reading positions and the center of the hole periphery control area, and converting the measured coordinates of the reference holes to the same coordinate system defined by three-dimensional translation and three-dimensional rotation angles of the assembly reference frame; And calculating three actually measured hole position deviation items according to the aligned reference hole coordinates, respectively corresponding to three coordinate components of the assembly reference frame, and keeping the component definition consistent with the hole position deviation target for carrying out subsequent opening adjustment judgment in process constraint.
9. The cooling valve position correction method based on micro-strategy optimization according to claim 1, wherein S6 is specifically: comparing the three measured hole position deviation items with deviation threshold values component by component, respectively judging whether all the three coordinate components of the assembly reference frame meet the deviation threshold values, and making consistency judgment on the three components corresponding to the hole periphery control area; Solidifying the opening of each cooling loop of the executable valve position instruction in the three stages of pressure maintaining, primary cooling and final cooling into final valve position setting when all deviation thresholds are met, and listing the opening of each cooling loop one by one and keeping the corresponding consistency of time segments of the conversion relation with the valve position; when the deviation threshold is not met, the valve position updating curve is corrected in stages in the process constraint according to the influence coefficient and the hole position deviation target direction, the opening correction amount is obtained according to the pressure maintaining, primary cooling and final cooling three-stage progressive cooling loops, the change amplitude of each time is limited, the total cooling capacity, the upper and lower opening limits and the opening change rate are met, and meanwhile, the valve position conversion relation and the definition of a hole periphery control area are kept unchanged; And mapping the corrected valve position updating curve into three sections of adjustment of the heat dissipation intensity of the mold wall through a valve position conversion relation to form secondary valve position setting, and outputting the secondary valve position setting according to a cooling loop and three stages for subsequent trial production and re-judgment.

Description

Cooling valve position correction method based on micro-strategy optimization Technical Field The invention relates to the technical field of thermoplastic composite material molding and warping control, in particular to a cooling valve position correction method based on micro-strategy optimization. Background In the process of mould pressing and in-mould cooling, the thermoplastic composite material is influenced by anisotropic shrinkage caused by crystallization dynamics and fiber orientation, and warpage and assembly reference hole position deviation are easy to occur. The rib plate components are distributed by rib plate constraint and cooling loops, so that the temperature gradient and shrinkage coupling are remarkable, and the requirement on the consistency of hole positions and assembly references is high. The engineering is generally to perform staged temperature control and cooling control according to pressure maintaining, primary cooling and final cooling, and combines with the prediction of the molding property of the thermoplastic composite material to support quality control. With the application of the parallel circuit and the adjustable valve position, the reliable mapping of the valve position and the water inlet and outlet temperature to the boundary heat dissipation and the alignment with the assembly coordinates form a closed-loop control foundation. The prior art mainly comprises a thermal-crystallization-structural coupling analysis or experience model based on CAE, which is used for predicting the warping and hole position deviation of a composite material piece, setting the process parameters such as dwell time, cooling strength and the like offline according to the warping and hole position deviation, and optimizing a cooling system at a tool side and a device side by adjusting a mold temperature machine strategy, a cooling channel layout and a parallel loop opening or optimizing a mold and a gate so as to improve a temperature field and shrinkage distribution. And part of the method introduces anisotropic shrinkage and an orientation/placement field to predict the molding performance, and adopts an assembly coordinate system to perform alignment and quality judgment at a measuring end for guiding subsequent processing or assembly. The existing scheme comprises the first step of lacking the integrated expression of a model for converting three-stage valve position opening and water inlet and outlet temperatures into mold wall heat radiation intensity through pipe resistance and split flow, the second step of enabling hole position deviation reading to be not uniformly defined in a hole periphery control area consistent with an assembly reference, and difficult to realize direct closed loop of prediction and actual measurement, and the third step of enabling a staged influence coefficient for quantifying an opening-hole position deviation relation in process constraint to be not formed, and difficult to determine effective adjustment direction and amplitude of a parallel circuit. Therefore, a cooling valve position correction method capable of solving the above-described deficiencies of the prior art is a problem that needs to be solved by those skilled in the art. Disclosure of Invention The invention aims to provide a cooling valve position correction method based on micro-strategy optimization, and aims to construct a prediction-control-measurement closed loop for alignment of three-stage valve position-heat dissipation mapping and assembly reference of a thermoplastic composite rib plate on the premise of not changing a die and a gate, so that the reference hole position deviation is stabilized and corrected to be the valve position setting executable by equipment and meets the requirement of an assembly threshold. According to the embodiment of the invention, the cooling valve position correction method based on micro-strategy optimization comprises the following steps: S1, in the in-mold cooling of a thermoplastic composite rib plate, acquiring valve position opening and water inlet and outlet temperatures of a cooling loop, establishing an assembly reference frame, calculating a reference Kong Piancha, and determining the upper limit and the lower limit of the opening, the total cooling capacity, the opening change rate and the deviation threshold value under the condition that a mold and a gate are not changed to form a process constraint and hole site deviation target; S2, constructing a thermal structure warping model for coupling crystallization and anisotropic shrinkage and fixing a material orientation field according to valve position opening, water temperature, an assembly reference frame, process constraint and a hole position deviation target, setting a hole periphery control area, representing the hole position deviation by using area center displacement, converting the valve position opening into the mold wall heat radiation intensity of three stages of pressure m