Integrated thermal forming door ring size breeding method

Abstract

The invention discloses an integrated thermal forming door ring size breeding method, and relates to the technical field of automobile manufacturing processes, and the method comprises the steps: designing an offset tolerance in an easy-to-interfere region based on a product mathematical model; a reference scheme is determined through CAE simulation optimization based on the digital analog with the offset tolerance; parts are manufactured according to the reference scheme, and a matching analysis gauge with a whole-process positioning function is constructed; the part is installed on the testing fixture according to the reference scheme; detecting and recording a matching problem by using a pre-configured measuring tool; correcting the defective part and verifying the defective part on a testing fixture until the defective part is qualified; marking #-shaped line marks at qualified positions; the marked part is adjusted on a welding clamp to be aligned with the testing fixture and then is welded; and finally, the welding assembly is reassembled to the gauge for measurement, and the problem is confirmed to be eliminated. According to the method, through systematic closed-loop control, the size breeding precision and efficiency are remarkably improved, and the development period is shortened.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of automobile manufacturing processes, in particular to a method for sizing an integrally thermoformed door ring. BACKGROUND

[0002] In order to meet the high requirements of the automobile industry under the national "double carbon" policy, light weight and low carbon integrated intensive manufacturing, a side wall reinforcement plate adopts an integrally thermoformed door ring structure. This integrally thermoformed door ring structure is divided into two types. The first type is an integrally thermoformed single door ring structure, which integrates the A-pillar upper reinforcement plate, the A-pillar reinforcement plate, the B-pillar reinforcement plate and the door sill reinforcement plate into an integrated thermoformed single piece. Through the integration of fewer parts, the number of tool fixtures is reduced, the process is reduced, and the storage / transportation / management cost of parts is reduced. The second type is an integrally thermoformed double door ring structure, which further integrates the C-pillar, the rear section of the door sill and the rear section of the upper side beam into an integrated thermoformed single piece based on the integrally thermoformed single door ring structure. This structure has fewer parts, which can further reduce the tool storage cost, but also brings the problem that the dimensional accuracy of large-size thermoforming is difficult to guarantee, and the overall process sizing cycle is long due to the lack of process sizing methods. SUMMARY

[0003] The purpose of the present application is to provide an integrally thermoformed door ring sizing method, which at least solves the problems of difficult dimensional accuracy of large-size thermoforming and long process sizing cycle due to the lack of process sizing methods.

[0004] The present application provides the following solutions:

[0005] According to one aspect of the present application, an integrally thermoformed door ring sizing method is provided, which comprises the following steps:

[0006] Based on the product model of the integrally thermoformed door ring, a bias tolerance with a preset direction and offset is designed in the area where interference with the counterpart is prone to occur during assembly;

[0007] Based on the product model of the integrally thermoformed door ring with the bias tolerance, stress simulation analysis is performed through CAE software, and the reference scheme for part detection and tool matching is optimized and determined according to the stress distribution results obtained from the analysis;

[0008] According to the optimized and determined reference scheme, an integrally thermoformed door ring and associated parts are manufactured, and a matching analysis gauge with full-process positioning function is constructed;

[0009] The manufactured integrally thermoformed door ring and associated parts are installed on the matching analysis gauge according to the reference scheme;

[0010] Using pre-configured measurement tools to detect the gap and surface difference of the parts positioned on the matching analysis fixture, identifying and recording the existing matching problems;

[0011] Correcting the parts with identified problems and verifying their lap joint status on the matching analysis fixture until the requirements are met;

[0012] Marking the word line marks for identifying the qualified status on the parts matching position with the lap joint status meeting the requirements;

[0013] Assembling the parts with the word line marks to the welding fixture, adjusting the mark status on the parts to align with the status on the matching analysis fixture, and then welding;

[0014] Reinstalling the welded body assembly to the matching analysis fixture for measurement, confirming that the identified matching problems have been eliminated.

[0015] Further, the process of designing the offset tolerance with a preset direction and offset amount includes:

[0016] Analyzing the product model of the one-piece thermoformed door ring, determining its matching relationship with each counterpart, and identifying the matching areas prone to interference during assembly;

[0017] For each identified interference-prone area, set specific offset positions, offset directions, and offset amounts according to its structural characteristics and assembly path, forming the set offset tolerance;

[0018] In the manufacturing process file of the one-piece thermoformed door ring, the set offset tolerance is embodied and executed.

[0019] Further, the process of optimizing the determination of the reference scheme for part detection and tool matching includes:

[0020] Converting the one-piece thermoformed door ring product model with the offset tolerance into a geometric model for CAE analysis;

[0021] Importing the geometric model into the CAE software and applying material properties, constraint conditions, and pre-deformation amount simulating the manufacturing process;

[0022] Setting candidate reference surfaces and reference points on the geometric model and performing stress simulation calculation to obtain the stress distribution results of the parts;

[0023] Based on the stress distribution results, iteratively adjusting and optimizing the positions and quantities of the candidate reference surfaces and reference points until the stress values meet the preset requirements, and outputting the final reference scheme.

[0024] Furthermore, the process of manufacturing the integrated thermoformed door ring and related parts, and constructing a matching analysis fixture with full-process positioning function includes:

[0025] Based on the positioning information defined by the optimized benchmark scheme, the integrated thermoformed door ring and related parts are manufactured.

[0026] Simultaneously, based on the aforementioned benchmark scheme, a fixture body is designed, and benchmark pins and benchmark surfaces corresponding to the benchmark scheme are machined on the fixture body;

[0027] On the fixture body, for key matching positions of the integrated thermoformed door ring and its associated parts, a detachable contouring structure manufactured according to the product 3D data at a 1:1 scale is set.

[0028] The tooling integrates inspection tools for measuring gaps and surface differences, and reserves measurement space for a portable coordinate measuring machine, forming the matching analysis fixture with full-process positioning function.

[0029] Furthermore, the process of installing the manufactured integrated thermoformed door ring and related parts onto the matching analysis fixture according to the benchmark scheme includes:

[0030] The water tank connecting plate, which is the associated part, and the integrated thermoformed door ring are placed at the corresponding installation position of the matching analysis fixture;

[0031] Using the reference pins and reference surfaces machined on the matching analysis fixture, the water tank connecting plate and the integrated thermoformed door ring are positioned, and a detection block is installed to lock them together.

[0032] The hinge reinforcement plate and sill reinforcement plate, which are the associated parts, are installed at the corresponding positions of the matching analysis fixture;

[0033] The hinge reinforcement plate and the sill reinforcement plate are positioned using the corresponding reference pins and reference surfaces on the matching analysis fixture.

[0034] Furthermore, the process of identifying and recording existing matching problems includes:

[0035] Place the reference end and measuring stylus of the pre-configured face difference meter in the measuring tool on the high and low steps of the face difference meter quick calibration block, respectively, and perform a zeroing operation to calibrate the measuring tool.

[0036] Using the pre-configured and calibrated surface difference table, gap gauge and caliper, the profile of the integrated thermoformed door ring and its associated parts is measured to obtain the actual surface difference value and the actual gap value.

[0037] Using the pre-configured internal scribing detection pin, the part hole position at the bottom of the matching analysis fixture is measured. The internal scribing detection pin is inserted into the corresponding hole of the fixture, so that it contacts the part and rotates to scribing the theoretical hole position circle on the surface of the part.

[0038] The measured actual surface difference value is compared with the actual gap value, and the theoretical hole position circle is compared with the actual hole position of the part. Based on the comparison results, interference and gap matching problems are identified and recorded.

[0039] Furthermore, the process for correcting the identified problematic parts includes:

[0040] For the identified matching problems, the integral thermoformed door ring or related parts with deviations are manually corrected;

[0041] The manually corrected parts are then reinstalled onto the matching analysis fixture according to the aforementioned benchmark scheme.

[0042] Using the pre-configured measuring tool, the gap and surface difference of the reinstalled parts are checked again. This process is repeated until the actual gap and surface difference values ​​of all measuring points meet the standard requirements, confirming that the overlap condition meets the requirements.

[0043] Furthermore, the process of drawing the character lines used to identify the qualified status includes:

[0044] After confirming that the overlap of the parts meets the requirements on the matching analysis fixture, use the pre-configured scribing needle and ruler to mark the overlap matching position of the parts with grid lines.

[0045] Each line of the grid markings must penetrate at least two overlapping parts, and any two parallel lines must maintain a distance of at least 20mm between them.

[0046] Furthermore, the process of assembling the part with the letter markings onto the welding fixture, and adjusting the marking state on the part to align with the state on the matching analysis fixture, includes:

[0047] The parts marked with tic-tac-toe lines are transferred from the matching analysis fixture and assembled onto the corresponding process fixture on the welding production line.

[0048] On the welding fixture, the position and orientation of the part are manually adjusted so that the grid line markings on the part are restored to the alignment state when they were confirmed to be qualified on the matching analysis fixture;

[0049] After adjusting the alignment, the parts are clamped and fixed on the welding fixture, and the position changes of the "well" lines of the parts in the free state, the clamped state, and the post-weld state are recorded.

[0050] Furthermore, the process of reinstalling the welded vehicle body assembly onto the matching analysis fixture for measurement includes:

[0051] After welding, the vehicle body assembly is installed onto the matching analysis fixture according to the benchmark scheme.

[0052] Using the pre-configured measuring tools, the gaps and surface differences of the parts of the vehicle body assembly where matching problems were previously identified are re-measured.

[0053] The data obtained from the retest is compared with the standard value. If the data meets the standard, it is confirmed that the previously identified matching problem has been eliminated and the verification result is valid.

[0054] If the retest data still does not meet the standard, the welding fixture will be checked and adjusted between processes based on the recorded data on the position changes of the "well" lines.

[0055] The above solution achieves the following beneficial technical effects:

[0056] In this invention, the pre-offset direction and offset amount are designed in advance by offset tolerance to avoid the problem, which can reduce the time of two rounds of mold modification and verification.

[0057] This invention uses CAE to analyze the integrated thermoformed door ring in advance, determine the reasonable reference quantity and placement direction, ensure the consistency between the gauge measuring bracket and the matching tooling, reduce unknown values, and save the problem analysis and judgment cycle.

[0058] This invention utilizes matching tooling to quickly identify matching interference gap problems in a single process, thereby improving analysis efficiency. Attached Figure Description

[0059] Figure 1 This is a flowchart of a method for growing the size of an integral thermoformed door ring according to one or more embodiments of the present invention. Detailed Implementation

[0060] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Please see the appendix Figure 1 A method for developing the dimensions of an integrally thermoformed door ring includes the following steps:

[0062] Based on the product digital model of the integrated thermoformed door ring, an offset tolerance with a preset direction and offset is designed in the area where assembly interference with the counterpart is likely to occur.

[0063] Furthermore, the process for designing offset tolerances with preset directions and offsets includes:

[0064] Analyze the product model of the integrated thermoformed door ring to determine its matching relationship with each counterpart component, and identify the matching areas that are prone to interference during the assembly process;

[0065] For each identified area prone to interference, based on its structural characteristics and assembly path, specific offset locations, offset directions, and offset amounts are set to form the set offset tolerances.

[0066] The established offset tolerances are reflected and implemented in the manufacturing process documentation for the one-piece thermoformed door ring.

[0067] Specifically, based on the 3D digital model of the integrated thermoformed door ring, engineers comprehensively analyze the matching relationship between the door ring and surrounding components, such as the side panel, front and rear doors, and fenders, in a computer-aided design software environment. They focus on analyzing areas with potential risks in the assembly path and identify matching areas prone to interference through the software's spatial analysis function or human experience. These areas are usually characterized by small gaps, complex overlapping relationships, or areas sensitive to tolerance accumulation.

[0068] For each identified interference-prone area, the offset parameters are finely set based on its specific structural characteristics, assembly motion trajectory, and tolerance accumulation direction. This includes setting the offset location, offset direction, and offset amount. Setting the offset location aims to clarify on which specific surface or boundary of the door ring the tolerance offset needs to be applied. Setting the offset direction aims to determine in which direction the tolerance center should be offset to avoid interference. For example, to increase the assembly clearance, the tolerance center is offset away from the opposing component. Setting the offset amount aims to determine a specific offset value based on historical experience data, CAE analysis, or tolerance simulation results. This offset amount aims to ensure that within the tolerance zone, the parts tend towards a safer assembly state.

[0069] The aforementioned offset location, offset direction, and offset amount are clearly marked in the part drawings or 3D model definition of the integrated thermoformed door ring. At the same time, they are reflected in the manufacturing process documents that guide production, such as stamping process cards and mold debugging instructions, to ensure that the designed offset tolerance can be accurately processed and inspected during mold manufacturing and part production.

[0070] By using the above-mentioned offset tolerance design, the central trend of the size distribution of the part is controlled in advance at the beginning of the part manufacturing process, which effectively reduces the probability of interference during trial assembly and batch assembly. This method can shorten the mold modification verification cycle, which originally required about four rounds, by one to two rounds, and significantly improve the efficiency and success rate of size development.

[0071] Based on the digital model of an integrated thermoformed door ring product with offset tolerance, stress simulation analysis was performed using CAE software. Based on the stress distribution results obtained from the analysis, a benchmark scheme for part inspection and tooling matching was optimized and determined.

[0072] Furthermore, the process for optimizing and determining the baseline scheme for part inspection and tooling matching includes:

[0073] Convert the digital model of a one-piece thermoformed door ring product with offset tolerances into a geometric model for CAE analysis;

[0074] Import the geometric model into the CAE software and apply material properties, constraints, and pre-deformation amounts to simulate the manufacturing process;

[0075] Candidate reference planes and reference points are set on the geometric model, and stress simulation calculations are performed to obtain the stress distribution results of the parts;

[0076] Based on the stress distribution results, the positions and numbers of candidate reference surfaces and reference points are iteratively adjusted and optimized until the stress values ​​meet the preset requirements, and the final reference scheme is output.

[0077] Specifically, using CATIA software, the digital model of the one-piece thermoformed door ring product with offset tolerance is fabricated into a sheet structure, and this sheet structure is saved as an IGES format file to generate a geometric model for CAE analysis. The generated IGES format geometric model is imported into AutoForm software, the material thickness direction is confirmed in the software, and the spatial position of the part is adjusted to the analysis station. Subsequently, corresponding material parameters are specified for the geometric model in the software, detection conditions are added, and a pre-deformation amount for simulating manufacturing springback is applied. A digital model containing all candidate datum planes and datum points is created using CATIA software and exported as an IGES format file. This datum plane is then imported into AutoForm software. According to the instructions, add locating pins to the geometric model and specify their control direction. Select the imported candidate datum planes and datum points as positioning constraints. After completing the settings, click the calculation button to perform stress simulation analysis. The software updates and outputs the stress distribution cloud map of the part. Analyze the stress distribution cloud map, focusing on the stress concentration near the locating points. Based on the magnitude and distribution of stress values, adjust the spatial position and number of candidate datum planes and datum points in the CATIA software. Repeat the simulation calculation process until the stress values ​​of the part at each candidate datum point are lower than the preset allowable stress threshold. This indicates that the deformation and internal force distribution of the part under this datum scheme have reached the optimal state. At this time, the final determined datum point position, number and direction information are output as the optimized datum scheme.

[0078] Through the above CAE simulation optimization process, the required reference positions and quantities of inspection tools and fixtures can be scientifically determined, and the placement direction of parts can be standardized, thereby ensuring the consistency between the inspection tool measuring bracket and the matching fixture reference system, reducing unknown deviation values ​​in the measurement and matching process, and saving the problem analysis and judgment cycle.

[0079] Based on the optimized baseline scheme, manufacture an integrated thermoformed door ring and related parts, and construct a matching analysis fixture with full-process positioning function.

[0080] Furthermore, the process of manufacturing an integrated thermoformed door ring and related parts, and constructing a matching analysis fixture with full-process positioning capabilities includes:

[0081] Based on the positioning information defined by the optimized baseline scheme, manufacture an integrated thermoformed door ring and related parts;

[0082] Meanwhile, based on the benchmark scheme, the fixture body is designed, and benchmark pins and benchmark surfaces corresponding to the benchmark scheme are machined on the fixture body;

[0083] On the fixture body, a detachable contouring structure manufactured according to the product 3D data at a 1:1 scale is set up for key matching positions of the integrated thermoformed door ring and its related parts.

[0084] It integrates inspection tools for measuring gaps and surface differences, and reserves measurement space for a portable coordinate measuring machine, forming a matching analysis fixture with full-process positioning function.

[0085] Specifically, based on the final benchmark scheme output after CAE simulation optimization, the scheme clearly defines the positioning information of the parts in inspection and tooling. Based on this positioning information, the manufacturing department uses hot stamping forming process to manufacture the integrated hot-formed door ring, and uses corresponding processes to manufacture its related parts, including the water tank connecting plate, hinge reinforcement plate and sill reinforcement plate.

[0086] Simultaneously, the manufacturing of the matching analysis fixture is carried out. First, based on the final benchmark scheme, the structural design of the fixture body is carried out and metal materials are used for processing. On the finished fixture body, according to the coordinate positions, types and dimensions defined in the benchmark scheme, the benchmark pins and benchmark surfaces for positioning the integrated thermoformed door ring and related parts are precision machined. On the fixture body, for the key matching areas of the integrated thermoformed door ring and related parts such as the water tank connecting plate, hinge reinforcement plate, and sill reinforcement plate, based on the original 3D data of the product, a detachable contouring structure manufactured at a 1:1 scale is designed and installed. These contouring structures can accurately simulate the profile of the parts and are used to directly inspect the matching gap. A special gauge for measuring gaps and surface differences is integrated and fixed on the fixture body. At the same time, in the structural layout of the fixture, sufficient operating space is planned in advance to ensure that the probe of the portable coordinate measuring machine can reach all the feature positions that need to be measured. Finally, a matching analysis fixture with full-process positioning function is formed, which integrates positioning, clamping, profile contouring and multi-means measurement functions.

[0087] This implementation method ensures that the manufactured physical parts and the matching analysis fixtures both originate from the same scientifically optimized benchmark system, guaranteeing their consistency. The dedicated fixtures have the capability of full-process positioning and multi-functional integrated measurement, providing a foundation for subsequent rapid and accurate physical matching verification.

[0088] The manufactured integrated thermoformed door ring and related parts are installed onto the matching analysis fixture according to the benchmark scheme.

[0089] Furthermore, the process of installing the manufactured one-piece thermoformed door ring and related parts onto the matching analysis fixture according to the benchmark scheme includes:

[0090] The water tank connecting plate, which is an associated component, and the integrated thermoformed door ring are placed in the corresponding installation position of the matching analysis fixture.

[0091] Using the reference pins and reference surfaces machined on the matching analysis fixture, the water tank connecting plate and the integrated thermoformed door ring are positioned, and the detection block is installed to lock them together.

[0092] The hinge reinforcement plate and sill reinforcement plate, which are related parts, are installed at the corresponding positions of the matching analysis fixture;

[0093] The hinge reinforcement plate and the sill reinforcement plate are positioned by using the corresponding reference pins and reference surfaces on the matching analysis fixture.

[0094] Specifically, the operator first places the water tank connecting plate, which is the associated part, on the matching analysis fixture at its preset installation position. Then, the integrated thermoformed door ring is hoisted or transported to the main body installation position on the matching analysis fixture. Using the reference pins and reference surfaces that are precision machined for the parts on the matching analysis fixture, the placed water tank connecting plate and integrated thermoformed door ring are precisely positioned to ensure that the parts are fully fitted with all the corresponding reference pins and reference surfaces on the fixture. Then, a detection block with a detection profile is installed to clamp the parts. The parts are then locked to the fixture body by the detection block using a quick clamping device or bolts to fix their position and prevent them from moving during subsequent testing. The detection block is a rigid module designed based on the 3D data of the parts to be tested. Its functions are to provide clamping force and for its own profile to serve as a detection reference for comparison measurement of gaps or surface differences with the parts.

[0095] After completing the installation and locking of the water tank connecting plate and the integrated thermoformed door ring, the operator continues to install the hinge reinforcement plate and sill reinforcement plate, which are related parts, onto the corresponding installation positions preset for these parts on the matching analysis fixture. Using the corresponding reference pins and reference surfaces specially machined for the hinge reinforcement plate and sill reinforcement plate on the matching analysis fixture, these parts are precisely positioned. At this stage, the reference system is usually used to maintain the position of the parts, or a light clamping device is used to assist in the measurement of gaps and surface differences.

[0096] The step-by-step installation and positioning process specified in this embodiment ensures that all related parts can be accurately joined under a unified and optimized reference coordinate system, providing a prerequisite for subsequent accurate gap and surface difference measurements and identification of matching problems.

[0097] Use pre-configured measuring tools to detect gaps and surface differences in parts positioned on the matching analysis fixture, identify and record existing matching problems.

[0098] Furthermore, the process for identifying and recording existing matching problems includes:

[0099] Place the reference end and measuring stylus of the pre-configured face difference meter in the measuring tool on the high and low steps of the face difference meter quick calibration block, respectively, and perform a zeroing operation to calibrate the measuring tool.

[0100] Using a pre-configured and calibrated surface difference meter, gap gauge and caliper, the profile of the integrated thermoformed door ring and its associated parts is measured to obtain the actual surface difference value and the actual gap value.

[0101] Using a pre-configured internal scribing detection pin, the part hole position at the bottom of the matching analysis fixture is measured. The internal scribing detection pin is inserted into the corresponding hole of the fixture, so that it contacts the part and rotates to scribing the theoretical hole position circle on the surface of the part.

[0102] The measured actual surface difference value is compared with the actual gap value, and the theoretical hole position circle is compared with the actual hole position of the part. Based on the comparison results, interference and gap matching problems are identified and recorded.

[0103] Specifically, the operator takes the face difference meter pre-configured next to the fixture, places the reference end of the face difference meter stably on the high step of the face difference meter quick calibration block, and simultaneously places the measuring needle of the face difference meter vertically on the low step of the face difference meter quick calibration block. After the pointer stabilizes, the dial is rotated to zero the scale, completing the face difference meter calibration operation. Using the calibrated face difference meter, a slight pressure is applied to its measuring needle so that it is perpendicular to the surface of the part being measured, and the dial reading is read directly. This reading is the actual face difference value. Using a pre-configured gap gauge, the gauge pieces of different thicknesses are inserted into the gap between the part and the contour block on the fixture until a slight resistance is felt. At this point, the thickness of the selected gauge piece is the actual gap value. For parts where it is difficult to use a gap gauge, calipers are used for auxiliary measurement. The above measurements are performed on all key matching surfaces of the integrated thermoformed door ring and its associated parts, and all actual face difference values ​​and actual gap values ​​are recorded.

[0104] For mounting holes of parts located at the bottom of the matching analysis fixture and not easily observed directly, a pre-configured internal scribing detection pin is used for measurement. The guide end of the internal scribing detection pin is inserted into the corresponding positioning hole on the fixture body, and the scribing pin is pushed forward so that the scribing needle at the top contacts the surface of the part. The contact pressure is maintained, and the internal scribing detection pin is rotated one revolution so that the scribing needle scribbles a complete circular mark on the surface of the part. This circular mark is the theoretical correct position of the mounting hole. The actual surface difference and actual gap data obtained by the above measurement are compared with the product design standard values ​​one by one. The theoretical hole position circle is visually compared with the actual hole position of the part to observe the degree of deviation between the actual hole edge and the theoretical circular mark. The judgment is made based on the comparison results. If the actual gap value is less than the lower limit of the standard value, it is recorded as an interference problem. If the actual gap value is greater than the upper limit of the standard value, it is recorded as a gap too large problem. If there is a deviation between the actual hole position and the theoretical circular mark, it is recorded as a hole position out of tolerance problem. All identified problems, their positions, and deviations are recorded in detail.

[0105] This implementation method systematically applies a variety of specialized measuring tools to achieve comprehensive quantitative detection and qualitative analysis of part surfaces, gaps, and hole positions. It can quickly and accurately locate and record various dimensional problems existing in the matching process, providing a clear direction and basis for subsequent part correction.

[0106] Correct the parts that are identified as having problems, and verify their overlap status on the matching analysis fixture until they meet the requirements.

[0107] Furthermore, the process for correcting the identified problematic parts includes:

[0108] For the identified matching problems, manual corrections are made to the integral thermoformed door rings or related parts that have deviations;

[0109] The manually corrected parts were reinstalled onto the matching analysis fixture according to the benchmark scheme.

[0110] Using pre-configured measuring tools, the gap and surface difference of the reinstalled parts are checked again. This process is repeated until the actual gap and surface difference values ​​at all measuring points meet the standard requirements, confirming that the overlap condition meets the requirements.

[0111] Specifically, based on the recorded problem list, the specific parts with dimensional deviations are located. These parts can be a single piece of integrated thermoformed door ring or related parts. The deviations are corrected manually. For areas with local interference, a pneumatic grinder with a grinding wheel or sandpaper of the appropriate grit is used to grind until the interference is eliminated. For areas with excessive gaps, if the gaps are caused by part deformation, a sheet metal hammer, shims, or other tools are used for careful straightening. The manually corrected parts are then reinstalled onto the matching analysis fixture according to the benchmark scheme determined by CAE analysis and optimization. That is, the reference pins and reference surfaces on the fixture are used to accurately position the parts, and the parts, along with other related parts, are reinstalled and locked onto the fixture in a predetermined order and manner.

[0112] Using pre-configured measuring tools, including calibrated face difference tables, gap gauges, and calipers, the gaps and face differences of the corrected and reinstalled parts are fully inspected again at the measurement points where the problems occurred and at key feature points. The new actual gap values ​​and actual face difference values ​​are obtained. The data obtained from the retest are compared with the product design standard values. If the data of all measurement points are within the standard value range, the overlapping state of the part is determined to meet the requirements, and the correction is successful.

[0113] If, during the retest, the data at any measurement point still does not meet the standard requirements, the above operation is repeated, namely, repositioning, manual correction, reinstallation verification, and retesting, until the actual gap value and actual surface difference value of all measurement points continuously and stably meet the standard requirements.

[0114] This implementation method, through rapid iteration of detection-correction-verification, can efficiently and accurately eliminate dimensional deviations of parts on matching analysis fixtures. This method solves problems before the welding process, avoids introducing defects into the assembly, greatly shortens the dimensional development cycle, and reduces the time required for production line debugging.

[0115] Mark the qualified status of the parts at the matching positions where the lap joint meets the requirements.

[0116] Furthermore, the process of creating letter marks to indicate a qualified status includes:

[0117] On the matching analysis fixture, after confirming that the overlapping state of the parts meets the requirements, use the pre-configured scribing needle and ruler to mark the overlapping matching position of the parts with a grid pattern.

[0118] Each crisscross mark must pass through at least two overlapping parts, and any two parallel crisscross marks must be at least 20mm apart.

[0119] Specifically, on the matching analysis fixture, all parts are installed, inspected, and corrected. Measuring tools are used to confirm that the gap and surface difference values ​​of all key measuring points meet the product design standards. At this point, the overlapping state of the parts is deemed to meet the requirements. Subsequently, using the scribing needle and metal ruler pre-configured next to the fixture, the operator uses the scribing needle and ruler to draw clear grid lines on the surface of the overlapping matching positions of the parts. When scribing, it is necessary to ensure that each straight scribing line spans at least two overlapping parts. At the same time, the vertical distance between any two parallel scribing lines in the grid line is controlled to ensure that the distance is not less than 20 mm. The grid line marks are used to indicate that the relative spatial position relationship of the relevant parts has been confirmed to be qualified in this specific state. As a visual reference, the mark's function is to accurately transfer the ideal overlapping state of the parts on the matching analysis fixture to the subsequent welding production process.

[0120] The grid-like markings used in this implementation method establish an intuitive and reliable reference symbol connecting offline fixtures and online production lines. This marking ensures that the qualified assembly state can be accurately reproduced on the welding fixture, providing a physical basis for accurate state transmission and subsequent problem tracing, and effectively solving the matching problem caused by the inconsistency between the fixture state and the production line state.

[0121] The parts with markings are assembled onto the welding fixture. The markings on the parts are adjusted to align with the markings on the matching analysis fixture before welding is performed.

[0122] Furthermore, the process of assembling parts with markings onto welding fixtures and aligning the markings on the parts with their state on the matching analysis fixture includes:

[0123] The parts marked with tic-tac-toe lines are transferred from the matching analysis fixture and assembled onto the corresponding process fixture on the welding production line.

[0124] On the welding fixture, manually adjust the position and orientation of the part so that the grid lines on the part are restored to their alignment state when they were confirmed to be qualified on the matching analysis fixture.

[0125] After adjusting the alignment, the parts are clamped and fixed on the welding fixture, and the position changes of the "well" lines of the parts in the free state, the clamped state, and the post-weld state are recorded.

[0126] Specifically, the operator removes the parts marked with tic-tac-toe lines from the matching analysis fixture and transfers them to the corresponding station on the welding production line through the logistics system. Then, these parts are initially placed into the positioning and clamping mechanism set for them on the welding fixture. On the welding fixture, the operator manually fine-tunes the position and spatial orientation of the parts. The goal of the adjustment is to restore the original shape of the tic-tac-toe lines on the surface of the parts, that is, the continuity and relative position of each line in the marking are completely consistent with the alignment state when they were finally confirmed to be qualified on the matching analysis fixture. This state indicates that the relative position of the parts on the current welding fixture has matched the ideal overlapping state on the fixture.

[0127] After adjusting to ensure the grid lines are fully aligned, activate the clamping device of the welding fixture to securely fix the parts in their current state. Then, record the following key data: free state record, clamped state record, and post-weld state record. For the free state record, before clamping, observe and record whether the grid lines are deformed or misaligned due to the weight of the parts or residual stress. For the clamped state record, after clamping but before welding begins, observe and record again whether the grid lines change due to the clamping force. For the post-weld state record, after welding is completed and the fixture is released, observe and record the shape of the grid lines, focusing on whether the marks are twisted, broken, or have obvious stepped misalignment after welding.

[0128] This implementation method achieves precise transmission of assembly status through grid-line marking, ensuring that the welding status on the production line is consistent with the ideal status verified by offline fixtures. At the same time, by recording the marking change data in three key states, it provides objective and direct quantitative basis for subsequent analysis of welding deformation, fixture positioning accuracy, and diagnosis of the root cause of matching problems, which greatly shortens the problem investigation cycle.

[0129] The welded body assembly was reinstalled on the matching analysis fixture for measurement, confirming that the identified matching problem had been eliminated.

[0130] Furthermore, the process of reinstalling the welded body assembly onto the matching analysis fixture for measurement includes:

[0131] After welding, the body assembly is installed onto the matching analysis fixture according to the benchmark scheme;

[0132] Using pre-configured measuring tools, gaps and surface differences were re-measured on the parts of the body assembly where matching problems had been identified.

[0133] The data obtained from the retest is compared with the standard value. If the data meets the standard, it is confirmed that the previously identified matching problem has been eliminated and the verification result is valid.

[0134] If the retest data still does not meet the standard, the welding fixture will be checked and adjusted between processes based on the recorded data on the position changes of the "well" lines.

[0135] Specifically, the welded body-in-white side panel assembly or related sub-assemblies are transferred to the matching analysis fixture area using hoisting equipment. Based on the same benchmark scheme determined by CAE analysis and optimization, the body assembly is precisely installed onto the matching analysis fixture. That is, the body assembly is positioned and supported using the benchmark pins and benchmark surfaces on the fixture. Using pre-configured measuring tools, including surface difference tables, gap gauges, and calipers, the gaps and surface differences on the specific parts of the body assembly where matching problems were previously recorded are measured again to obtain the actual gap value and actual surface difference value of the welded assembly.

[0136] All data obtained from the retest are compared one by one with the product design standard values. If all retest data are within the standard value range, it is determined that the matching problems identified in the previous single-piece and sub-assembly matching stages have been eliminated, proving that the verification results of this growth method are effective and the size growth target of this round has been achieved. If, during the comparison, it is found that the retest data of any part still does not meet the standard, it indicates that the problem has not been completely solved. At this time, the data on the position change of the grid line recorded when the part is assembled into the welding fixture is analyzed. If the record shows that the grid line is obviously misaligned after welding, the root cause of the problem may be welding thermal deformation or welding sequence. If the record shows that the grid line has already deformed when the fixture is clamped, the root cause of the problem may be that there is a deviation in the positioner or clamper of the welding fixture. Based on this analysis conclusion, the corresponding welding fixture is precisely checked and adjusted between processes, rather than modifying the parts again.

[0137] This implementation method completes the final closed-loop verification of dimensional growth. It can not only confirm the final effect of problem solving, but more importantly, when the problem has not been eliminated, it can use the previously recorded process data to accurately guide the analysis of the problem from the part level to the welding process or tooling fixture level. This enables the rapid and accurate location of the problem and the differentiation of responsibilities, avoids blind part mold repair, and improves the efficiency and quality of problem solving.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for developing the dimensions of an integrally thermoformed door ring, characterized in that, The method includes the following steps: Based on the product digital model of the integrated thermoformed door ring, an offset tolerance with a preset direction and offset is designed in the area where assembly interference with the counterpart is likely to occur. Based on the digital model of the integrated thermoformed door ring product with the aforementioned offset tolerance, stress simulation analysis was performed using CAE software. Based on the stress distribution results obtained from the analysis, a benchmark scheme for part inspection and tooling matching was optimized and determined. Based on the optimized baseline scheme, manufacture an integrated thermoformed door ring and related parts, and construct a matching analysis fixture with full-process positioning function; The manufactured integrated thermoformed door ring and related parts are installed onto the matching analysis fixture according to the benchmark scheme; The gap and surface difference of the parts positioned on the matching analysis fixture are detected using pre-configured measuring tools, and the existing matching problems are identified and recorded. Correct the parts that are identified as having problems, and verify their overlap status on the matching analysis fixture until they meet the requirements; Mark the qualified status of the parts at the matching positions where the lap joint meets the requirements; The part with the letter markings is assembled onto the welding fixture, and the markings on the part are adjusted to align with the markings on the matching analysis fixture before welding is performed. The welded body assembly was reinstalled on the matching analysis fixture for measurement, confirming that the identified matching problem had been eliminated.

2. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process of designing offset tolerances with preset directions and offsets includes: Analyze the product digital model of the integrated thermoformed door ring to determine its matching relationship with each of the opposing parts, and identify the matching areas that are prone to interference during the assembly process; For each identified area prone to interference, based on its structural characteristics and assembly path, specific offset locations, offset directions, and offset amounts are set to form the set offset tolerances. The set offset tolerances are reflected and implemented in the manufacturing process documents of the integrated thermoformed door ring.

3. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process for optimizing and determining the baseline scheme for part inspection and tooling matching includes: The digital model of the integral thermoformed door ring product with the aforementioned offset tolerance is converted into a geometric model for CAE analysis; Import the geometric model into the CAE software and apply material properties, constraints, and pre-deformation amounts to simulate the manufacturing process; Candidate reference planes and reference points are set on the geometric model, and stress simulation calculations are performed to obtain the stress distribution results of the parts; Based on the stress distribution results, the positions and numbers of the candidate reference surfaces and reference points are iteratively adjusted and optimized until the stress values ​​meet the preset requirements, and the final reference scheme is output.

4. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process of manufacturing an integrated thermoformed door ring and related parts, and constructing a matching analysis fixture with full-process positioning function includes: Based on the positioning information defined by the optimized benchmark scheme, the integrated thermoformed door ring and related parts are manufactured. Simultaneously, based on the aforementioned benchmark scheme, a fixture body is designed, and benchmark pins and benchmark surfaces corresponding to the benchmark scheme are machined on the fixture body; On the fixture body, for key matching positions of the integrated thermoformed door ring and its associated parts, a detachable contouring structure manufactured according to the product 3D data at a 1:1 scale is set. The tooling integrates inspection tools for measuring gaps and surface differences, and reserves measurement space for a portable coordinate measuring machine, forming the matching analysis fixture with full-process positioning function.

5. The method for developing the dimensions of an integrally thermoformed door ring according to claim 4, characterized in that, The process of installing the manufactured integrated thermoformed door ring and related parts onto the matching analysis fixture according to the benchmark scheme includes: The water tank connecting plate, which is the associated part, and the integrated thermoformed door ring are placed at the corresponding installation position of the matching analysis fixture; Using the reference pins and reference surfaces machined on the matching analysis fixture, the water tank connecting plate and the integrated thermoformed door ring are positioned, and a detection block is installed to lock them together. The hinge reinforcement plate and sill reinforcement plate, which are the associated parts, are installed at the corresponding positions of the matching analysis fixture; The hinge reinforcement plate and the sill reinforcement plate are positioned using the corresponding reference pins and reference surfaces on the matching analysis fixture.

6. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process for identifying and recording existing matching problems includes: Place the reference end and measuring stylus of the pre-configured face difference meter in the measuring tool on the high and low steps of the face difference meter quick calibration block, respectively, and perform a zeroing operation to calibrate the measuring tool. Using the pre-configured and calibrated surface difference table, gap gauge and caliper, the profile of the integrated thermoformed door ring and its associated parts is measured to obtain the actual surface difference value and the actual gap value. Using the pre-configured internal scribing detection pin, the part hole position at the bottom of the matching analysis fixture is measured. The internal scribing detection pin is inserted into the corresponding hole of the fixture, so that it contacts the part and rotates to scribing the theoretical hole position circle on the surface of the part. The measured actual surface difference value is compared with the actual gap value, and the theoretical hole position circle is compared with the actual hole position of the part. Based on the comparison results, interference and gap matching problems are identified and recorded.

7. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process for correcting the identified problematic parts includes: For the identified matching problems, the integral thermoformed door ring or related parts with deviations are manually corrected; The manually corrected parts are then reinstalled onto the matching analysis fixture according to the aforementioned benchmark scheme. Using the pre-configured measuring tool, the gap and surface difference of the reinstalled parts are checked again. This process is repeated until the actual gap and surface difference values ​​of all measuring points meet the standard requirements, confirming that the overlap condition meets the requirements.

8. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process of drawing the character lines used to identify the qualified status includes: After confirming that the overlap of the parts meets the requirements on the matching analysis fixture, use the pre-configured scribing needle and ruler to mark the overlap matching position of the parts with grid lines. Each line of the grid markings must penetrate at least two overlapping parts, and any two parallel lines must maintain a distance of at least 20mm between them.

9. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process of assembling the part with the letter markings onto the welding fixture, and adjusting the marking state on the part to align with the state on the matching analysis fixture, includes: The parts marked with tic-tac-toe lines are transferred from the matching analysis fixture and assembled onto the corresponding process fixture on the welding production line. On the welding fixture, the position and orientation of the part are manually adjusted so that the grid line markings on the part are restored to the alignment state when they were confirmed to be qualified on the matching analysis fixture; After adjusting the alignment, the parts are clamped and fixed on the welding fixture, and the position changes of the "well" lines of the parts in the free state, the clamped state, and the post-weld state are recorded.

10. The method for developing the dimensions of an integrally thermoformed door ring according to claim 1, characterized in that, The process of reinstalling the welded vehicle body assembly onto the matching analysis fixture for measurement includes: After welding, the vehicle body assembly is installed onto the matching analysis fixture according to the benchmark scheme. Using the pre-configured measuring tools, the gaps and surface differences of the parts of the vehicle body assembly where matching problems were previously identified are re-measured. The data obtained from the retest is compared with the standard value. If the data meets the standard, it is confirmed that the previously identified matching problem has been eliminated and the verification result is valid. If the retest data still does not meet the standard, the welding fixture will be checked and adjusted between processes based on the recorded data on the position changes of the "well" lines.

Images