Method and system for improving assembly precision of automobile front face

Abstract

The invention belongs to the technical field of automobile assembly, and provides a method and system for improving automobile front face assembly precision, and the method comprises the following steps: by taking a hinge hole in a front door of an automobile body side wall as a reference, mounting a front face tool part on an automobile body through a first harness, and fixing a fender bracket on the automobile body side wall; a hood assembly is installed through a second installation tool by taking the front face tool piece as the benchmark; installing a front-end module through a third harness by taking the front-face tool piece as a benchmark; a fender is installed through a fender support, so that the rear portion of the fender is precisely positioned on the front face tool piece in the X direction and the Y direction; the front portion of the fender is roughly positioned on the front end module in the X direction and the Y direction. The assembly precision is high, the manual adjustment amount is small, and the automobile front face sensory quality can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile assembly, and particularly relates to a method and system for improving assembly precision of a front face of an automobile. BACKGROUND

[0002] In automobile modeling and engineering design, the front face area is the visual focus, and the quality thereof directly determines the perceived quality of the whole vehicle. The area integrates a fender, a hood, a front bumper, a headlamp, a grille and a plurality of other components, and the matching relationship is extremely complex. The gap, the surface difference, the parallelism and the symmetry are all required to be of high precision. Therefore, designing a front face size control scheme to ensure the matching precision between each component is a very systematic and complex engineering.

[0003] In the front face system, the fender and the hood assembly are two largest outer coverings, and constitute the main frame and the visual basis of the front face. The matching state of the two (especially the XY plane direction determining the installation position) is a prerequisite for determining the overall qualification rate of the front face. Controlling the matching between the two assemblies establishes a stable and reliable reference for the installation of other components.

[0004] In the prior art scheme, as shown in FIG. 1, the rear part of the fender is matched with the front door through a gap surface difference, and the front part is matched with the front door through a fixture. Figures 1 to 4 The assembly process is as follows:

[0005] First, the fender is assembled. The XY direction of the fender is positioned on the water channel of the vehicle body through a fender fixture 1, and the Y direction of the front part of the fender is positioned through a fixture diamond pin.

[0006] The fender is matched with the front door through a gap and a surface difference. The fender is matched with the front door through a fender fixture 2 and a fender fixture 3. The gap is ensured through a round pin, and the surface difference is ensured through a magnet.

[0007] The hood is matched with the front door through a gap and a surface difference. The XY direction of the hood is positioned on the water channel of the vehicle body through a hood fixture. Two positioning pins on the hood fixture position the XY direction of the hood assembly. In the prior art assembly method, the manual adjustment amount is large. Figure 5

[0008] ​In order to improve the assembly precision of the front face of the automobile, relevant technical personnel have developed various assembly methods, for example, the patent with publication number CN116118907B discloses a kind of automobile front face assembly positioning method, comprising the following steps: S1, headlamp upper crossbeam is assembled to the engine compartment framework of vehicle body, water tank upper crossbeam is assembled to headlamp upper crossbeam and the engine compartment framework of vehicle body, and the engine compartment framework of vehicle body is provided with a clearance between headlamp upper crossbeam;S2, engine cover is positioned by engine cover lock catch and engine cover buffer block to realize the front part of engine cover, realize the appearance matching of fender, headlamp;S3, headlamp is positioned by the positioning hole on fender and headlamp bolt to realize X, Y direction positioning, and Z direction positioning assembly is realized by headlamp upper crossbeam mounting point.Effectively break the original long size chain, reestablish assembly datum on the front face of whole vehicle, improve the assembly precision of engine cover, fender, headlamp, and improve the fine degree of appearance of whole vehicle.But this method introduces water tank upper crossbeam as a new datum, which may increase the complexity of vehicle body structure and the number of parts. SUMMARY

[0009] In view of the deficiencies in the prior art, the present application provides a method and system for improving the assembly precision of the front face of an automobile, which has high assembly precision, small manual adjustment amount and can significantly improve the sensory quality of the front face of the automobile.

[0010] To achieve the above and related purposes, the present application adopts the following technical solutions:

[0011] The first aspect of the present application provides a method for improving the assembly precision of the front face of an automobile, comprising the following steps:

[0012] Step S1. With the front door upper hinge hole of the vehicle body side as the datum, install the front face tooling piece on the vehicle body by the first tool, and fix the fender support on the vehicle body side;

[0013] Step S2. With the front face tooling piece as the datum, install the hood assembly by the second tool;

[0014] Step S3. With the front face tooling piece as the datum, install the front end module by the third tool;

[0015] Step S4. Install the fender through the fender support, so that the rear part of the fender is precisely positioned in X and Y directions on the front face tooling piece; the front part of the fender is coarsely positioned in X and Y directions on the front end module.

[0016] Further, in step S1, taking the front door upper hinge hole of the vehicle body side as the datum comprises: inserting the first positioning pin of the first tool into the left and right front door upper hinge holes of the vehicle body side for X and Y direction positioning, sliding the Y direction centering mechanism of the first tool, and completing Y direction automatic centering based on the left and right front door upper hinge holes.

[0017] Further, in step S1, the first fixture further comprises a locking pin, and the use condition of the locking pin comprises that the locking pin is in a pulled-out state when the first fixture is used for three-coordinate calibration.

[0018] Further, the front face tooling piece further comprises a front face reference hole, the second fixture is aligned with the front face reference hole through a second positioning pin of the second fixture, and the front face tooling piece is used as a reference.

[0019] Further, in step S2, the second fixture further comprises a part placing guide and a hood assembly positioning pin, the second fixture positions the hood assembly in the X direction and the Y direction through the second positioning pin, and the hood assembly is installed on the vehicle body through the part placing guide and the hood assembly positioning pin.

[0020] Further, in step S3, the third positioning pin comprises a round pin and a diamond pin, the third fixture positions the front end module in the X direction and the Y direction on the vehicle body through the round pin and the diamond pin, and the front end module is fixed on the vehicle body in the Z direction through a locking piece of the third fixture.

[0021] Further, in step S4, the front face tooling piece further comprises a positioning hole, the fender further comprises a first pin, and the fender is inserted into the positioning hole through the first pin, so that the rear part of the fender is precisely positioned in the X direction and the Y direction on the front face tooling piece.

[0022] Further, in step S4, the front end module further comprises a mounting hole, the fender further comprises a second pin, and the fender is inserted into the mounting hole through the second pin, so that the front part of the fender is coarsely positioned in the X direction and the Y direction on the front end module, wherein the second pin and the mounting hole have a gap.

[0023] Further, the front end module is provided with a front end module support.

[0024] The second aspect of the present application provides a system for improving the assembly precision of an automobile front face, which uses the above method for assembly, and the system comprises a front face tooling piece, a first fixture for mounting the front face tooling piece on a vehicle body, a second fixture for mounting a hood assembly, a third fixture for mounting a front end module, and a fender support for mounting a fender.

[0025] The present application has the beneficial technical effects that:

[0026] The present application directly or indirectly positions the hood assembly, the front end module and the fender based on the same reference, i.e., the front face tooling piece, instead of positioning each on different parts of the vehicle body, so that the cumulative error caused by the vehicle body tolerance and multiple independent references can be avoided, and the relative precision in the X direction and the Y direction between the fender and the hood assembly can be ensured.

[0027] The present application uses the left and right front door upper hinge holes of the body side as a reference, installs the front face tooling piece to the vehicle body by using a first tool, thereby establishing the accurate local reference of the entire front face assembly; uses a second tool to ensure that the XY direction position of the hood assembly is completely determined by the front face tooling piece reference; uses a third tool to ensure that the XY direction position of the front end module is also determined by the same reference, and to provide support for the next step of positioning the front part of the fender; the rear part of the fender is accurately positioned on the front face tooling piece, the XY direction is controlled, the front part of the fender is coarsely positioned on the installed front end module, and a single-sided gap is left, so that the fender is installed with high precision, and the position is jointly constrained by the rear part and the front part, and a very high relative precision is formed with the hood assembly.

[0028] The present application has high assembly precision, small manual adjustment amount, can significantly improve the sensory quality of the front face of the automobile, and has strong universality and is suitable for similar structure vehicle models.

[0029] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings incorporated into the specification and forming part of the specification, show embodiments consistent with the present application, and together with the specification, serve to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0031] Figure 1 Prior art fender tool and its assembly drawing;

[0032] Figure 2 Prior art fender assembly drawing on the vehicle body water channel;

[0033] Figure 3 Prior art fender assembly drawing;

[0034] Figure 4 Prior art hood assembly drawing;

[0035] Figure 5 In the prior art assembly method, the X direction size chain calculation result of the fender and the hood assembly;

[0036] Figure 6 Structure schematic diagram of the front face tooling piece of the present application;

[0037] Figure 7 Structure schematic diagram of each installation position of the front face tooling piece of the present application;

[0038] Figure 8 Assembly drawing of the front face tooling piece of the present application installed on the vehicle body;

[0039] Figure 9 An exemplary first fixture structure schematic diagram of the present application;

[0040] Figure 10 Another exemplary first fixture structure schematic diagram of the present application;

[0041] Figure 11 A front face fixture assembly schematic diagram of the present application;

[0042] Figure 12 An exemplary second fixture structure schematic diagram of the present application;

[0043] Figure 13 Another exemplary hood assembly schematic diagram of the present application;

[0044] Figure 14 An exemplary front end module assembly schematic diagram of the present application;

[0045] Figure 15 A third fixture assembly schematic diagram of the present application;

[0046] Figure 16 Another exemplary front end module assembly schematic diagram of the present application;

[0047] Figure 17 A fender assembly schematic diagram of the present application;

[0048] Figure 18 Dimension chain calculation results of the present application.

[0049] 1: front face fixture; 11: front face mounting hole; 12: positioning hole; 13: front face reference hole; 14: first positioning pin; 15: Y-direction centering mechanism; 16: locking pin; 17: support block; 18: Z-direction support and compression member; 2: hood assembly; 21: second positioning pin; 3: front end module; 22: part placement guide; 23: hood assembly positioning pin; 31: third positioning pin; 311: round pin; 312: diamond pin; 32: locking member; 4: fender; 41: fender support; 42: first pin; 43: second pin; 33: front end module support. DETAILED DESCRIPTION

[0050] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application pertains. It is to be understood that certain features that are, for clarity, described in the context of separate embodiments can also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment can also be provided separately or in any suitable combination. The use of numbering in the claims is intended to supplement, not supersede, a classification that is determined according to the patent classification art and may, in some embodiments, be used to advantage in referencing particular aspects of the present application. Certain features that are, for brevity, described in the context of several embodiments, can also be provided in combination in a single embodiment. To the extent that specific construction details of the application are described in connection with various specific embodiments, it is contemplated that one of ordinary skill in the art can employ those details in connection with the embodiments, but is not limited to only those specific details. It is intended to cover and embrace all alternatives, modifications and equivalents. The following further description of the application will be made by way of specific examples, but it is to be understood that these examples are provided by way of explanation of the application and are not intended to limit the scope of the application, which is to be determined by the appended claims. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0051] As shown in Figures 6 to 17 The present application provides a method for improving the assembly accuracy of the front face of a vehicle, comprising the following steps:

[0052] Step S1. With the front door upper hinge hole of the vehicle body side as a reference, the front face tooling piece 1 is installed on the vehicle body by a first tooling, and the fender support 41 is fixed on the vehicle body side;

[0053] Step S2. With the front face tooling piece 1 as a reference, the hood assembly 2 is installed by a second tooling;

[0054] Step S3. With the front face tooling piece 1 as a reference, the front end module 3 is installed by a third tooling;

[0055] Step S4. The fender 4 is installed through the fender support 41, so that the rear X direction and Y direction of the fender 4 are precisely positioned on the front face tooling piece 1; the front X direction and Y direction of the fender 4 are roughly positioned on the front end module 3.

[0056] Further, as shown in Figures 6 to 11As shown, in step S1, the upper hinge hole of the front door of the body side is used as a reference to include: using the first positioning pin 14 of the first tool to insert the upper hinge hole of the left and right front door of the body side to position in X and Y directions, driving the Y direction centering mechanism 15 of the first tool to slide, and completing the automatic centering in Y direction with the left and right front door upper hinge hole as a reference. The present application uses the left and right front door upper hinge hole of the body side as a global reference point, because the manufacturing precision of the two hinge holes is high and the position is stable. After the first positioning pin 14 is inserted into the hinge hole, the position of the first tool in X and Y directions is determined; after the first positioning pin 14 is inserted into the hinge hole, the Y direction centering mechanism 15 will automatically slide to ensure that the first tool is accurately centered in Y direction (lateral direction of the body) relative to the left and right upper hinge hole.

[0057] Further, in step S1, the first tool further includes a locking pin 16, and the use condition of the locking pin 16 includes that when the first tool is used for three-coordinate calibration, the locking pin 16 is in the pulled-out state during the execution of step S1. The locking pin 16 of the present application is only used when the three-coordinate measuring machine is calibrated to fix the position, and when the actual production and installation work is carried out, the locking pin 16 must be in the pulled-out state.

[0058] Further, the present application uses the Z direction support and pressing member 18 to press the first tool on the body. Furthermore, the present application provides two fender supports 41 on each side of the body. The present application places the front face tool 1 (one on each side) on the first tool which is accurately positioned, the first positioning pin 14 is accurately inserted into the front face reference hole 13 of the front face tool 1, at the same time, the support block 17 with magnet on the first tool will attract the front face tool 1 to make it initially in place, and finally the front face tool 1 is completely installed on the body design position through the fastening member such as bolt. After the installation is completed, the first tool is removed, at this time, the position accuracy of the front face tool 1 is guaranteed by the high-precision hinge hole reference, which becomes a new reference for subsequent installation.

[0059] Further, as shown in Figure 7 The front face tool 1 of the present application further includes a front face reference hole 13, the second positioning pin 21 of the second tool is aligned with the front face reference hole 13 to complete the reference with the front face tool 1, and the third positioning pin 31 of the third tool is aligned with the front face reference hole 13 to complete the reference with the front face tool 1.

[0060] Further, as shown in Figure 12 and Figure 13As shown, in step S2, the second fixture further comprises a placing guide 22 and a hood assembly positioning pin 23. The second fixture positions the hood assembly 2 in the X direction and the Y direction through the second positioning pin 21, and installs the hood assembly 2 on the vehicle body through the placing guide 22 and the hood assembly positioning pin 23. The present application is accurately positioned to the front face reference hole 13 of the already installed front face tooling part 1 through the second positioning pin 21, and the hood assembly 2 is hoisted or placed on the second fixture. The mounting hole on the hood assembly 2 cooperates with the hood assembly positioning pin 23, so that the hood assembly 2 is accurately positioned in the XY plane. Further, the second fixture of the present application is further provided with a plurality of lightening holes, and necessary supports are provided, such as left and right symmetrical engine cover supports. Then the operator fastens the hood assembly 2 to the hinges of the vehicle body. Since the position of the hood assembly 2 is completely determined by the front face tooling part 1, the installation position accuracy is high.

[0061] Further, as shown in Figures 14 to 16 The third positioning pin 31 comprises a round pin 311 and a diamond pin 312. The third fixture positions the front end module 3 in the X direction and the Y direction on the vehicle body through the round pin 311 and the diamond pin 312, and fixes the front end module 3 in the Z direction on the vehicle body through the locking piece 32 of the third fixture. The front end module 3 of the present application is provided with a left circular hole and a right waist hole, and is positioned on the front face reference hole 13 of the front face tooling part 1 through the third positioning pin 31, and is placed on the third fixture. The round pin 311 and the diamond pin 312 on the third fixture accurately position the front end module 3 in the XY direction, and then the front end module 3 is fixed in the Z direction on the vehicle body longitudinal beam and the like through the locking piece 32. At this time, the installed front end module 3 not only has accurate position itself, but also provides rough positioning support for the front part of the fender 4.

[0062] Further, the front end module 3 of the present application further comprises a front end module support 33 for bearing, which serves as an integrated platform to provide mounting hole positions for front headlamps, hood locks and the like, and is connected with the vehicle body longitudinal beam to transmit the weight and collision force of the entire front end module 3 to the vehicle body main structure. The front end module support 33 is provided with a fixture positioning hole 12, a Z-direction clamping, a front headlamp related interface, and a hood lock mounting hole.

[0063] Further, as shown in Figure 17 In step S4, the front face tooling part 1 further comprises a front face mounting hole 11 and a positioning hole 12, and the fender 4 comprises a first plug pin 42. The fender 4 is inserted into the positioning hole 12 through the first plug pin 42, and the rear part of the fender 4 is accurately positioned on the front face tooling part 1 in the X direction and the Y direction.

[0064] Further, in step S4, the front end module 3 further comprises a mounting hole, and the fender 4 further comprises a second pin 43, the fender 4 is inserted into the mounting hole through the second pin 43, and the front part of the fender 4 is coarsely positioned on the front end module 3, wherein the second pin 43 has a gap with the mounting hole. In the application, the fender 4 is moved to the mounting position, the first pin 42 at the rear part of the fender 4 is accurately inserted into the front face mounting hole 11 of the front face tooling piece 1 fixed on the body side, at this time, the first pin 42 is in interference fit with the front face mounting hole 11, and the rear part of the fender 4 is determined in all degrees of freedom in the X direction and the Y direction, so as to ensure the gap and the surface difference between the fender 4 and the door and the hood assembly 2. After the rear part is positioned, the front part of the fender 4 is placed on the corresponding mounting point of the front end module 3, and is matched with the front end module 3 through the second pin 43, the matching is gap matching, and there is a single-sided gap of 0.5 mm, which is used for Z-direction support and rough limiting, and the front part is coarsely positioned in the XY direction. Then, the front part and the rear part of the fender 4 are fastened on the fender support 41.

[0065] The application further provides a system for improving the assembly precision of the front face of an automobile, which is assembled by using the above method, and comprises the front face tooling piece 1, a first tool for mounting the front face tooling piece 1 on the body, a second tool for mounting the hood assembly 2, a third tool for mounting the front end module 3, and a fender support 41 for mounting the fender 4.

[0066] Further, the system of the application is used as follows:

[0067] 1. The first tool is inserted into the left and right front door hinge holes of the body side through the first positioning pin 14, and the X direction and the Y direction are preliminarily positioned; the Y direction centering mechanism 15 of the first tool is driven to automatically slide and accurately center with the left and right upper hinge holes as the reference, and the transverse tolerance of the body itself is eliminated.

[0068] 2. The front face tooling piece 1 is placed on the first tool which has been accurately positioned, so that the first positioning pin 14 of the first tool is inserted into the front face reference hole 13 of the front face tooling piece 1, and at the same time, the fender support 41 is placed on the positioning point specified by the first tool, and the front face tooling piece 1 and the fender support 41 are fixed to the body by bolts. The first tool is removed, and the reference of the front face tooling piece 1 is established.

[0069] 3. The second tool is used, the second positioning pin 21 is matched with the front face reference hole 13 of the front face tooling piece 1, the second tool is accurately positioned, the hood assembly 2 is placed on the second tool, the mounting hole on the hood assembly 2 is matched with the hood assembly positioning pin 23, so that the hood assembly 2 is accurately positioned in the XY plane, and the hood assembly 2 is fastened to the body hinge under the assistance of the supporting and pressing mechanism of the second tool.

[0070] 4. Using the third fixture, the third positioning pin 31 is engaged with the front reference hole 13 of the front fixture 1 to make the third fixture itself accurately positioned. The front module 3 is placed on the third fixture. The round pin 311 and diamond pin 312 of the third fixture are engaged with the left round hole and right waist hole of the front module 3 to complete the accurate XY positioning. The front module 3 is tightened and fixed to the vehicle body by the Z-axis clamping mechanism such as the locking bolt.

[0071] 5. Accurately insert the first pin 42 at the rear of the fender 4 into the positioning hole 12 of the front face tooling 1 to restrict the XY-axis freedom of the rear of the fender 4 and ensure the accuracy of the gap between it and the hood assembly 2. After completing the rear positioning, place the front end of the fender 4 onto the mounting point of the pre-installed front end module 3. Through the clearance fit of the second pin 43, complete the Z-axis rough positioning, absorb manufacturing tolerances, and avoid assembly stress. Use tools to install the fender 4 onto the fender bracket 41 to complete the assembly.

[0072] Furthermore, in the traditional method, the assembly dimension chain includes the fender 4 precision, the fender 4 and front door X-axis assembly error, the front door assembly dimension, the front door hinge precision, the hinge assembly error, the side panel positioning hole 12 precision (fixture hole), the water channel positioning hole 12 precision (fixture hole), the hood assembly 2 assembly error, and the hood assembly 2 precision, with 9 items in the dimension chain. In contrast, the method and system of this application include the fender 4 precision, the fender 4 assembly error, the front face tooling part 1 precision, the hood assembly 2 assembly error, and the hood assembly 2 precision, containing 5 items. Compared to the traditional solution, the dimension chain is significantly shortened, and the X-axis matching precision of the fender 4 and hood assembly 2 is significantly improved by 58%. Figure 18 As shown, the method and system of this application require less manual adjustment compared to existing technologies.

[0073] Furthermore, this application adds a front-end tooling component 1, which connects the baselines of the side and front ends through this component. Most of the front-end components are also positioned through this component, effectively ensuring the front-end's localized touch (DTS). Compared to previous projects, this application shows an actual localized DTS improvement of approximately 20%, resulting in a significant improvement in the perceived quality of the front end. In addition, this application has strong versatility and is applicable to vehicle models with similar structures.

[0074] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for improving the assembly precision of a car's front fascia, characterized in that, Includes the following steps: Step S1. Using the hinge hole on the front door of the vehicle side panel as a reference, install the front face tooling (1) onto the vehicle body through the first fixture, and fix the fender bracket (41) on the vehicle side panel. Step S2. Using the front face tooling (1) as a reference, install the hood assembly (2) through the second fixture; Step S3. Using the front face tooling (1) as a reference, install the front end module (3) through the third fixture; Step S4. Install the fender (4) through the fender bracket (41) so that the rear part of the fender (4) is precisely positioned in the X and Y directions onto the front face tooling (1); the front part of the fender (4) is roughly positioned in the X and Y directions onto the front end module (3).

2. The method according to claim 1, characterized in that, In step S1, taking the hinge hole on the front door of the vehicle body side panel as a reference includes: using the first positioning pin (14) of the first fixture to insert into the hinge hole on the left and right front doors of the vehicle body side panel for X and Y direction positioning, driving the Y direction centering mechanism (15) of the first fixture to slide, and taking the hinge hole on the left and right front doors as a reference to complete the Y direction automatic centering.

3. The method according to claim 2, characterized in that, In step S1, the first device further includes a locking pin (16). The conditions for using the locking pin (16) include that when the first device is used for three-coordinate calibration, the locking pin (16) is in a pulled-out state during the execution of step S1.

4. The method according to claim 1, characterized in that, The front face tooling (1) also includes a front face reference hole (13). The second fixture aligns with the front face reference hole (13) through its second positioning pin (21) to complete the alignment with the front face tooling (1) as a reference. The third fixture aligns with the front face reference hole (13) through its third positioning pin (31) to complete the alignment with the front face tooling (1) as a reference.

5. The method according to claim 4, characterized in that, In step S2, the second fixture further includes a placement guide (22) and a hood assembly positioning pin (23). The second fixture positions the hood assembly (2) in the X and Y directions using the second positioning pin (21), and installs the hood assembly (2) onto the vehicle body using the placement guide (22) and the hood assembly positioning pin (23).

6. The method according to claim 4, characterized in that, In step S3, the third positioning pin (31) includes a round pin (311) and a diamond pin (312). The third fixture positions the front end module (3) to the vehicle body in the X and Y directions through the round pin (311) and the diamond pin (312), and the locking member (32) of the third fixture tightens and fixes the front end module (3) to the vehicle body in the Z direction.

7. The method according to claim 4, characterized in that, In step S4, the front face tooling (1) further includes a positioning hole (12), the fender (4) includes a first pin (42), the fender (4) is inserted into the positioning hole (12) through the first pin (42) to complete the precise positioning of the rear part of the fender (4) in the X and Y directions onto the front face tooling (1).

8. The method according to claim 7, characterized in that, In step S4, the front-end module (3) further includes a mounting hole, and the fender (4) further includes a second pin (43). The fender (4) is inserted into the mounting hole through the second pin (43) to complete the coarse positioning of the front part of the fender (4) in the X and Y directions onto the front-end module (3). There is a gap between the second pin (43) and the mounting hole.

9. The method according to claim 6, characterized in that, The front-end module (3) is provided with a front-end module bracket (33).

10. A system for improving the assembly precision of a car's front fascia, characterized in that, The system is assembled using the method described in any one of claims 1 to 9, the system comprising a front fascia fixture (1), a first fixture for mounting the front fascia fixture (1) onto the vehicle body, a second fixture for mounting the hood assembly (2), a third fixture for mounting the front end module (3), and a fender bracket (41) for mounting the fender (4).

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