High-smoothness appearance surface processing technology and device

Abstract

The invention relates to a high-smoothness appearance surface processing technology and device, and belongs to the technical field of surface processing, and the high-smoothness appearance surface processing technology comprises the following steps: S1, obtaining curvature distribution data of the edge of a charging port cover in real time through three-dimensional laser scanning, and establishing a partition geometric model comprising a straight line segment, a small fillet segment and a large fillet segment; s2, based on the curvature distribution data, a grinding assembly is regulated and controlled to adjust the grinding area of a straight line section, a small fillet section and a large fillet section in a self-adaptive mode; and S3, based on the partition geometric model, a grinding assembly is adjusted and controlled to grind the linear section, the small fillet section and the large fillet section in sequence, through a curvature self-adaptive dynamic machining system, the technical bottleneck of traditional fixed parameter grinding is broken through, high precision of a complex curvature surface is achieved, and the requirement of the charging port cover for high smoothness of the appearance surface can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of surface treatment, and in particular relates to a high-smoothness appearance surface processing technology and device. Background Art

[0002] With the rapid development of the new energy vehicle industry, high-precision, high-smoothness surface treatment processes for vehicle exterior components have become a core requirement for improving product quality. As a key component of vehicle exterior trim that combines functionality and aesthetics, the processing quality of the contour edges of the charging port cover directly affects the smoothness of the vehicle's appearance and the fit of the assembly. However, due to its lightweight design requirements, the charging port cover generally adopts a thin-walled structure and is made of high-strength aluminum alloy or carbon fiber composite materials. The following problems often arise during the edge finishing process: Traditional mechanical grinding processes use fixed large molds or uniformly distributed pressure application processes, which cannot dynamically adapt to the complex curvature changes of the edge of the charging port cover, such as the connection area between the R-angle transition zone and the straight line segment. When a constant clamping force is used in the straight line segment area, the rigid contact surface of the clamp and the sudden change area of the curvature of the charging port cover cannot form conformal contact, resulting in local pressure concentration and causing yield deformation of thin-walled parts.

[0003] However, in the large curvature arc section, due to the insufficient contact area of the fixture, the actual effective pressure is weakened, resulting in uncontrolled material removal rate and poor grinding effect in the rounded corner area. In addition, when the grinding equipment applies vertical pressure to the edge, thin-walled parts are prone to elastic deformation due to insufficient local rigidity, resulting in springback after processing, causing the actual contour to deviate from the theoretical design value by more than the preset value, ultimately affecting the assembly fit and smoothness of the charging port cover.

[0004] Therefore, a processing technology and device that can adaptively adjust according to the curvature of the edge of the charging port cover is needed. Summary of the Invention

[0005] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a high-smoothness appearance surface processing process and device to solve the problem that the edge section of the charging port cover has different curvatures and the existing processing method cannot adaptively process according to the curvature to ensure the appearance surface and line shape.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A high-smoothness appearance surface processing process, including the following contents: S1: Use 3D laser scanning to obtain real-time curvature distribution data of the charging port cover edge and establish a partitioned geometric model consisting of straight segments, small fillet segments, and large fillet segments; S2: Based on the curvature distribution data, the grinding component is controlled to adaptively adjust the grinding area of straight segments, small fillet segments and large fillet segments; S3: Based on the partitioned geometric model, the grinding component is controlled to grind the straight line segment-small fillet segment-large fillet segment in sequence.

[0007] Preferably, when the pressure of the polishing component is regulated in step S2, the polishing movement speed is reversely adjusted according to the real-time curvature radius, wherein: a) The straight section area uses the first pressure level to match the first speed range; b) The small rounded corner area adopts the second pressure level to match the second speed range; c) The third pressure level is used to match the third speed range in the large radius section; The first pressure level>the third pressure level>the second pressure level, and the corresponding matching first speed range<the third speed range<the second speed range.

[0008] Preferably, the negative pressure charging port cover is used to generate negative pressure adsorption control parameters based on the geometric model established in step S1; when the straight line segment is polished, the adsorption area is expanded to A1 and the adsorption pressure Q1 and the polishing pressure P1 satisfy Q1 / P1≥3:1.

[0009] Preferably, when the small fillet section is polished, the adsorption area is reduced to A2 and the adsorption pressure Q2 and the polishing pressure P2 satisfy 1:1<Q2 / P2<2:1.

[0010] Preferably, when the large radius section is polished, the adsorption area is dynamically adjusted to A3=A1·(1-ΔR / R0), where ΔR is the change in the curvature radius and R0 is the reference radius.

[0011] Preferably, S301: integrating an infrared temperature measurement module to monitor the temperature of the processing area in real time and establish a dynamic temperature field model; S302: When processing a straight segment, when the temperature exceeds 75°, the pressure compensation mechanism is triggered, the first pressure level is dynamically reduced, and the first speed range is increased.

[0012] A high-smoothness appearance surface processing device includes an adsorption component and a polishing component integrated in a base frame; the base frame is provided with a polishing area, the adsorption component is arranged at the lower part of the base frame and connected to the polishing area, and is used to adsorb the charging port cover; the polishing component is arranged at the upper part of the base frame and extends downward to the polishing area to polish the charging port cover.

[0013] Preferably, the polishing assembly includes a polishing frame, a polishing head, an adjusting block and a transmission block; the polishing frame is arranged on the base frame, the polishing head is installed on the polishing frame, the polishing head includes a fixed block and a movable block, the fixed block is fixedly installed at one end of the polishing frame, and the movable block is slidably installed at the other end of the polishing frame; the adjusting block is arranged between the movable block and the fixed block and is hinged to the movable block and the fixed block respectively, the adjusting block is connected to the movable polishing block through the transmission block, and the movable polishing block and the polishing head form a polishing part with a changing curvature, which is used to adapt to the curvature distribution data of the charging port cover.

[0014] Preferably, the transmission member is an elastic member.

[0015] Preferably, the adsorption device includes a plurality of adsorption ports, and the plurality of adsorption ports are arranged in a ring-shaped array. Each of the adsorption ports is provided with a solenoid valve, and the plurality of solenoid valves are opened or closed based on a partitioned geometric model.

[0016] The beneficial effects of the present invention are: This application breaks through the technical bottleneck of traditional fixed parameter grinding through a curvature-adaptive dynamic processing system, achieves high precision on complex curvature surfaces, and can ensure the high smoothness requirements of the charging port cover for the appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0018] Figure 1 A flowchart of a high-smoothness exterior surface processing process provided in one embodiment of the present invention; Figure 2 A schematic structural diagram of a high-smoothness surface processing device provided in one embodiment of the present invention; Figure 3 A schematic diagram of the charging port cover structure provided in one embodiment of the present invention; Figure 4 A schematic diagram of a connection structure of a grinding head provided in one embodiment of the present invention; Legend: 11. Base frame, 12. Grinding frame; 13. Grinding head; 131. Movable block; 132. Fixed block; 14. Adjusting block; 15. Transmission part; 16. Mobile grinding block; 2. Adsorption device; 2. Straight line segment; 3. Small rounded corner segment; 4. Large rounded corner segment. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] When polishing existing charging port covers, because they need to fit snugly with the vehicle body and maintain a consistent linear height, a uniform edge polishing method is used. This results in the completely different curvatures of the edge, particularly the straight and arc transition sections. Using a fixed polishing method, the larger curvature of the arc section requires more polishing area than the straight section. However, the polishing area of existing polishing tools is fixed, so it's easy for areas in the arc transition section to be missed, potentially requiring rework or even scrapping. Rework also makes it difficult to ensure consistency with the main body's linear shape and high smoothness.

[0021] like Figure 1-Figure 4 As shown, a high-smoothness appearance surface processing process includes the following contents: S1: Use 3D laser scanning to obtain real-time curvature distribution data of the charging port cover edge and establish a partitioned geometric model consisting of straight segments, small fillet segments, and large fillet segments; S2: Based on the curvature distribution data, the grinding component is regulated to adaptively adjust the grinding area of straight segments, small fillet segments, and large fillet segments. Specifically, the grinding component can adjust the wrapping area of the straight segments according to the curvature of each segment. The larger the curvature, the larger the wrapping area of the grinding component, thereby avoiding the omission of grinding segments in the arc segments. In this way, the overall line shape and high smoothness are consistent. In addition, the grinding component wraps around the charging port cover according to different curvatures for grinding. During grinding, it can also ensure that the center line speed of the grinding head matches the curvature, avoiding slippage during grinding, and thus making the edge linear consistent; S3: Based on the partitioned geometric model, the grinding components are controlled to grind the straight segments first, then the small rounded segments, and finally the large rounded segments, in this way.

[0022] In summary, the curvature-adaptive dynamic processing system has broken through the technical bottleneck of traditional fixed parameter grinding, achieved high precision on surfaces with complex curvatures, and can ensure the high smoothness requirements of the charging port cover for the appearance.

[0023] Based on the above-mentioned embodiment of zoned grinding, zoned grinding leads to uneven heat accumulation, which is specifically manifested as heat concentration in straight sections, and difficulty in heat dissipation in small and large fillet sections due to their arc structures.

[0024] In one embodiment, when the grinding assembly pressure is regulated in step S2, the grinding movement speed is reversely adjusted according to the real-time curvature radius, wherein: a) The first pressure level matches the first speed range in the straight section area, adopting a high-pressure, low-speed strategy. High pressure increases the grinding pressure per unit area, improving the material removal efficiency of a single grinding pass, reducing the number of repeated grindings, shortening the friction time, and thus reducing heat accumulation. Low speed reduces the grinding head movement speed, avoiding excessive instantaneous temperature rise caused by rapid friction, significantly reducing heat concentration in the straight section, preventing deformation, and ensuring linear height consistency. b) The second pressure level matches the second speed range in the small radius section, adopting a low-pressure, high-speed strategy. Low pressure reduces contact pressure and avoids local heat accumulation caused by heat dissipation difficulties. High speed accelerates the grinding head movement speed, shortens the single contact time, and uses high-speed airflow to assist in heat dissipation, reducing the heat retention time in the arc section. This effectively improves the heat dissipation problem in the small radius section, avoids surface micro-defects, and maintains the smoothness of the arc transition zone. c) The third pressure level matches the third speed range in the large radius section, adopting a medium-pressure, medium-speed strategy. This balances grinding pressure and travel speed, dynamically matching heat generation and heat dissipation. Medium pressure prevents localized overgrinding, while medium speed ensures grinding coverage and maintains temperature stability through continuous and uniform friction heat distribution. This prevents missed or overgrinding in the large radius section due to sudden changes in curvature, ensuring a smooth transition with the straight section.

[0025] In summary, dynamic matching of pressure and speed keeps the temperature rise of each section within a reasonable range, preventing material deformation or surface damage caused by heat accumulation. Straight sections require fewer re-grinding cycles, while speed control achieves thermal equilibrium in large and small radius sections, significantly reducing overall temperature gradients. An adaptive curvature strategy ensures uniform grinding across straight, small, and large radius sections, eliminating areas of missed grinding. The smooth linear transitions of the high-gloss exterior surface meet the stringent tolerances required for vehicle body assembly.

[0026] Since the edge of the charging port cover is being processed, the stable clamping of the charging port cover plays a key role in the processing quality. In addition, high-pressure grinding of the straight section causes a sudden increase in the normal shear force, and low-speed movement prolongs the single-point action time. The combination of the two can easily cause workpiece vibration and edge microcracks.

[0027] In one embodiment, negative pressure is used to absorb the charging port cover, and negative pressure adsorption control parameters are generated based on the geometric model established in step S1. When the straight segment is polished, the adsorption area is expanded to A1 and the adsorption pressure Q1 and the polishing pressure P1 satisfy Q1 / P1≥3:1. Through the above method, the adsorption pressure is at least 3 times the polishing pressure, forming a constraint field to suppress the vertical shear vibration generated by the high pressure direction. At the same time, the adsorption area A1 is expanded, the contact area is increased to disperse the stress, and the surface indentation caused by excessive local pressure is avoided.

[0028] It is easy to match the second speed range (high speed) with the second pressure level (low speed) in the small rounded corner section. Low speed grinding reduces the contact stability between the tool and the workpiece, resulting in edge over-throw and deformation of the thin-walled area. In one embodiment, when the small rounded corner segment is polished, the adsorption area is reduced to A2 to adapt to the curvature radius of the small rounded corner segment, and the adsorption area is reduced to match the arc contour to avoid the adsorption edge exceeding the effective contact surface of the workpiece, causing air leakage or local stress mutation.

[0029] Setting 1:1 < Q2 / P2 < 2:1 ensures that the adsorption pressure is slightly higher than the grinding pressure without over-constraining the workpiece. During high-speed movement, the adsorption system adjusts the negative pressure distribution in real time to ensure that the direction of the adsorption force is always aligned with the tangent direction of the grinding head's motion trajectory, offsetting tool deflection caused by centrifugal force. By reducing the concentrated area of adsorption area A2, the coverage of thin-walled areas is reduced, while maintaining the precise constraint of adsorption pressure Q2 at key force points, thus avoiding distributed deformation caused by large-area adsorption.

[0030] Q2 / P2>1 ensures the adsorption system consistently provides positive restraint, suppressing pressure fluctuations caused by tool vibration during high-speed grinding. The reduced adsorption area A2 improves pressure uniformity in the edge area, ensuring that the grinding pressure P2 is evenly distributed across the arc surface, eliminating the risk of localized over-throws.

[0031] Due to the continuous change of the curvature radius in the large rounded corner section, the fixed adsorption area will cause the fit between the adsorption surface and the workpiece in the area of sudden curvature change to decrease, local air leakage will cause the clamping force to fluctuate, and the fixed adsorption area cannot adapt to the curvature change, resulting in uneven pressure distribution and tensile stress concentration at the sudden curvature change, causing surface wrinkles or sub-surface damage.

[0032] In one embodiment, when polishing the large radius section, the adsorption area is dynamically adjusted to A3=A1·(1-ΔR / R0), where ΔR is the change in the curvature radius and R0 is the base radius. When the curvature increases (ΔR>0), the adsorption area A3 is proportionally reduced to reduce excessive coverage of the low curvature area and avoid air leakage caused by the suspended adsorption edge. The adsorption pressure is concentrated on the high curvature area (the section with a smaller curvature radius), thereby enhancing the restraint on the sudden change area.

[0033] When the curvature decreases (ΔR<0): the adsorption area A3 expands, increasing the coverage of the gently curvature area, dispersing the pressure to prevent local pressure from exceeding the standard, and the boundary of the adsorption surface smoothly extends along the curvature to eliminate the fitting gap; the dynamic adsorption area ensures that the pressure per unit area is inversely correlated with the curvature radius (high pressure in high curvature area, low pressure in low curvature area), offsetting the normal force difference caused by the curvature change. The adsorption system adjusts the area to match the deformation of the workpiece surface in real time, suppressing the accumulation of elastic deformation caused by grinding pressure.

[0034] During the high-pressure, low-speed grinding process of straight sections, continuous frictional heat generation can lead to: local excessive temperature (>75°C), causing softening of the metal material, destruction of the micro-grain structure, reduced surface hardness and corrosion resistance, thermal expansion difference between the high-temperature area and the non-high-temperature area, resulting in linear height deviation of the charging port cover. Materials such as aluminum alloy are prone to oxidation and discoloration at high temperatures, affecting the visual consistency of the high-smoothness appearance.

[0035] In one embodiment, S301: an infrared temperature measurement module is integrated to monitor the temperature of the processing area in real time and establish a dynamic temperature field model. The processing area is scanned to generate a temperature distribution thermogram, locate high-temperature points, and integrate parameters such as the thermal conductivity of the material and the environmental heat dissipation conditions to predict the temperature evolution trend and predict overheating risk areas in advance. S302: When processing a straight section, if the monitored temperature is >75°C, the compensation mechanism is automatically triggered to dynamically reduce the first pressure level (originally high pressure) according to the gradient, reducing the friction energy input per unit area, directly suppressing the temperature rise, and simultaneously increasing the first speed range (originally low speed), shortening the residence time of the grinding head in the high-temperature zone, accelerating heat dissipation, and the pressure reduction amplitude is positively correlated with the temperature limit value, and the speed increase amplitude matches the pressure reduction amplitude to ensure a constant material removal rate; after the pressure-speed adjustment, the temperature is continuously monitored until it drops back to the safety threshold (<65°C), and the initial parameters are gradually restored.

[0036] A high-smoothness surface processing device. The adsorption component generates a uniform negative pressure field in the grinding area through the adsorption port at the bottom of the base frame, stably adsorbing the charging port cover to the processing plane, ensuring that the workpiece does not move or vibrate during the grinding process. The grinding component drives the grinding head through the multi-degree-of-freedom robotic arm at the top of the base frame, and adaptively grinds the edge of the charging port cover with curvature according to a preset path (straight segment, small radius segment, large radius segment), while dynamically adjusting the pressure and speed.

[0037] In addition, integrated sensors collect pressure, temperature, and position data in real time, and feed it back to the control system to dynamically optimize adsorption force and polishing parameters, forming a "perception-decision-execution" closed loop.

[0038] In one embodiment, the grinding assembly includes a grinding frame, a grinding head and an adjusting block, and the grinding head and the adjusting block are both provided with independent grinding parts for processing the exterior surface; the grinding frame serves as a rigid support body, fixed on the base frame, and provides a stable motion track and mechanical bearing basis; the fixed block is rigidly fixed at one end of the grinding frame, serving as a reference anchor point for the grinding part; the movable block is connected to the other end of the grinding frame through a slide rail, and can slide along the axial direction of the grinding frame to achieve length adjustment and curvature adaptation of the grinding part; the adjusting block is hinged between the fixed block and the movable block to form a connecting rod mechanism.

[0039] There are several adjusting blocks hinged between the movable block and the fixed block, and several adjusting blocks are independent. When the movable block and the fixed block move relative to each other, the adjusting block moves toward the axis and drives the transmission part to generate tension, pulling the movable polishing block and the polishing head to produce relative movement, and the upper and lower ends of the movable polishing block form a polishing part with variable curvature between the movable block and the fixed block; the special movable block and the fixed block have an arc structure at one end adjacent to the movable polishing block, and then the curvature between the large module and the movable block and the fixed block is inconsistent with the moving distance of the movable polishing block, and the greater the moving distance of the movable block, the more obvious the depression of the polishing part; the more area of the charging port cover that can be wrapped, and thus it can be ensured that there will be no missing areas when polishing the small fillet section and the large fillet section, thereby ensuring the consistency of the overall line shape and appearance.

[0040] Furthermore, the transmission parts should be composed of a rigid structure to avoid the use of elastic transmission parts, which will result in insufficient contact with the workpiece due to elasticity when the mobile grinding block is processing the workpiece. Rigid structures such as metal rods can not only realize the movement of the mobile grinding block, but also generate sufficient contact support force when the mobile grinding block is used for grinding, thereby ensuring the grinding effect.

[0041] In one embodiment, the adsorption device includes a plurality of adsorption ports, which are evenly distributed in a ring along the outer edge of the grinding area, covering all curvature partitions of the charging port cover (straight line segment, small rounded corner segment, large rounded corner segment). Each adsorption port is configured with an independent solenoid valve. Based on the partition geometric model generated in step S1, the adsorption port group corresponding to the current grinding area is identified, and only the relevant solenoid valve is opened.

[0042] Straight segment adsorption: Open multiple adsorption ports directly below and adjacent to the straight segment, such as 6-8 in a row, to form a wide adsorption surface and enhance rigid constraint.

[0043] Arc segment adsorption: According to the arc curvature radius, selectively open the adsorption ports within the corresponding arc, such as 3-4 for small corners and 5-6 for large corners, to avoid air leakage from the edge adsorption ports hanging in the air.

[0044] Transition section coordination: the adsorption ports in adjacent areas are opened and closed in a gradient to ensure a smooth transition of adsorption force and eliminate sudden pressure changes.

[0045] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-smoothness appearance surface processing process, characterized in that: Includes the following: S1: Use 3D laser scanning to obtain real-time curvature distribution data of the charging port cover edge and establish a partitioned geometric model consisting of straight segments, small fillet segments, and large fillet segments; S2: Based on the curvature distribution data, the grinding component is controlled to adaptively adjust the grinding area of straight segments, small fillet segments and large fillet segments; S3: Based on the partitioned geometric model, the grinding component is controlled to grind the straight line segment-small fillet segment-large fillet segment in sequence.

2. A high-smoothness appearance surface processing process according to claim 1, characterized in that: When the pressure of the polishing component is controlled in step S2, the polishing movement speed is reversely adjusted according to the real-time curvature radius, wherein: a) The straight section area uses the first pressure level to match the first speed range; b) The small rounded corner area adopts the second pressure level to match the second speed range; c) The large radius section area adopts the third pressure level to match the third speed range; The first pressure level>the third pressure level>the second pressure level, and the corresponding matching first speed range<the third speed range<the second speed range.

3. A high-smoothness appearance surface processing process according to claim 2, characterized in that: Using negative pressure to suck the charging port cover, generate negative pressure adsorption control parameters based on the geometric model established in step S1; when grinding the straight line segment, the adsorption area is expanded to A1 and the adsorption pressure Q1 and the grinding pressure P1 satisfy Q1 / P1≥3:

1.

4. A high-smoothness appearance surface processing process according to claim 3, characterized in that: When grinding the small fillet section, the adsorption area is reduced to A2 and the adsorption pressure Q2 and the grinding pressure P2 satisfy 1:1<Q2 / P2<2:

1.

5. The high-smoothness appearance surface processing process according to claim 4, characterized in that: When grinding large radius sections, the adsorption area is dynamically adjusted to A3=A1·(1-ΔR / R0), where ΔR is the change in curvature radius and R0 is the reference radius.

6. The high-smoothness appearance surface processing process according to claim 1, characterized in that: S301: Integrates an infrared temperature measurement module to monitor the temperature of the processing area in real time and establish a dynamic temperature field model; S302: When processing a straight segment, when the temperature exceeds 75, the pressure compensation mechanism is triggered, the first pressure level is dynamically reduced, and the first speed range is increased.

7. A high-smoothness surface processing device, applicable to any one of claims 1-6, characterized in that: It includes an adsorption component and a polishing component integrated in the base frame; the base frame is provided with a polishing area, the adsorption component is arranged at the lower part of the base frame and connected to the polishing area, and is used to adsorb the charging port cover; the polishing component is arranged at the upper part of the base frame and extends downward to the polishing area to polish the charging port cover.

8. The high-smoothness appearance surface processing device according to claim 7, characterized in that: The polishing assembly includes a polishing frame, a polishing head, an adjusting block and a transmission block; the polishing frame is arranged on the base frame, the polishing head is installed on the polishing frame, the polishing head includes a fixed block and a movable block, the fixed block is fixedly installed at one end of the polishing frame, and the movable block is slidably installed at the other end of the polishing frame; the adjusting block is arranged between the movable block and the fixed block and is hinged to the movable block and the fixed block respectively, the adjusting block is connected to the movable polishing block through the transmission block, and the movable polishing block and the polishing head form a polishing part with a changing curvature, which is used to adapt to the curvature distribution data of the charging port cover.

9. The high-smoothness surface processing device according to claim 8, characterized in that: The transmission member is an elastic member.

10. The high-smoothness appearance surface processing device according to claim 7, characterized in that: The adsorption device includes a plurality of adsorption ports, which are arranged in a ring array. Each of the adsorption ports is provided with a solenoid valve, and the solenoid valves are opened or closed based on a partitioned geometric model.

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