High smoothness appearance surface processing technology and device

Abstract

The application relates to a high-continuity appearance surface processing technology and device, and belongs to the technical field of surface processing, and comprises the following contents: S1: curvature distribution data of a charging port cover edge is acquired in real time through three-dimensional laser scanning, and a partition geometry model containing a straight line segment, a small fillet segment and a large fillet segment is established; S2: based on the curvature distribution data, polishing assembly is adjusted to adaptively adjust polishing areas of the straight line segment, the small fillet segment and the large fillet; S3: based on the partition geometry model, the polishing assembly is adjusted to polish the straight line segment, the small fillet segment and the large fillet segment in sequence, through a curvature-adaptive dynamic processing system, a technical bottleneck of traditional fixed-parameter polishing is broken, high precision of a complex curvature surface is realized, and the high-continuity appearance surface requirement of the charging port cover can be guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface treatment, and particularly relates to a high smoothness appearance surface machining process and device. BACKGROUND

[0002] With the rapid development of the new energy automobile industry, a high-precision and high-smoothness surface treatment process of vehicle appearance parts has become a core requirement for improving product quality. As a key part with functionality and aesthetics in the vehicle body exterior, the machining quality of the contour edge of the charging port cover directly affects the smoothness and assembly fit of the vehicle appearance. However, due to the lightweight design requirement, the charging port cover generally adopts a thin-walled structure and selects high-strength aluminum alloy or carbon fiber composite material, and the following problems usually occur in the edge finishing process:

[0003] The traditional mechanical polishing process adopts a fixed large abrasive or a uniform pressure application process, 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 area and the straight line segment. When a constant clamping force is applied in the straight line segment area, the rigid contact surface of the clamp cannot form a conformal contact with the curvature mutation area of the charging port cover, resulting in local pressure concentration and causing thin-walled part yield deformation.

[0004] And in the large curvature arc segment, due to the insufficient contact area of the clamp, the actual effective pressure is actually attenuated, causing the material removal rate to be out of control, and the polishing effect of the fillet area is poor.

[0005] In addition, when the polishing equipment applies vertical pressure to the edge, the thin-walled part is prone to elastic deformation due to local rigidity deficiency, resulting in actual profile deviation from the theoretical design value after machining, which exceeds the preset value, and finally affects the assembly fit and smoothness of the charging port cover.

[0006] Therefore, a machining process and device capable of self-adaptive adjustment according to the curvature of the edge of the charging port cover are needed. SUMMARY

[0007] To solve the above problems in the prior art, the application provides a high-smoothness appearance surface machining process and device, which solves the problem that the existing machining method cannot adaptively machine the appearance surface and line type according to the different curvatures of the edge of the charging port cover.

[0008] The purpose of the application can be achieved by the following technical solutions:

[0009] A high-smoothness appearance surface machining process, comprising the following contents:

[0010] S1: Real-time acquisition of curvature distribution data of the edge of the charging port cover through three-dimensional laser scanning, establishment of a partitioned geometric model containing a straight line segment, a small fillet segment and a large fillet segment;

[0011] S2: Based on curvature distribution data, the grinding components adaptively adjust the grinding area of ​​straight segments, small rounded segments, and large rounded segments;

[0012] S3: Based on the partitioned geometry model, the grinding components are controlled to grind the straight line segment, small rounded corner segment, and large rounded corner segment in sequence.

[0013] Preferably, in step S2, when adjusting the pressure of the grinding component, the grinding movement speed is adjusted in the opposite direction according to the real-time radius of curvature, wherein:

[0014] a) The straight section area adopts the first pressure level matched with the first speed range;

[0015] b) The small rounded corner section area uses the second pressure level to match the second speed range;

[0016] c) The large rounded corner section area adopts the third pressure level matched with the third speed range;

[0017] The first pressure level > the third pressure level > the second pressure level, corresponding to the first speed range < the third speed range < the second speed range.

[0018] Preferably, the negative pressure adsorption charging port cover is used to generate negative pressure adsorption control parameters based on the geometric model established in step S1; when grinding the straight section, the adsorption area is expanded to A1 and the adsorption pressure Q1 and the grinding pressure P1 satisfy Q1 / P1≥3:1.

[0019] Preferably, during the polishing of the small rounded corner section, the adsorption area is reduced to A2 and the adsorption pressure Q2 and the polishing pressure P2 satisfy 1:1 < Q2 / P2 < 2:1.

[0020] Preferably, when polishing the large rounded corner section, the adsorption area is dynamically adjusted as A3=A1·(1-ΔR / R0), where ΔR is the change in the radius of curvature and R0 is the reference radius.

[0021] Preferably, 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;

[0022] S302: When machining on a straight section, if the temperature exceeds 75°C, the pressure compensation mechanism is triggered, which dynamically reduces the first pressure level and increases the first speed range.

[0023] A high-gloss 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 disposed in the lower part of the base frame and communicates with the polishing area, and is used to adsorb a charging port cover; the polishing component is disposed in the upper part of the base frame and extends downward to the polishing area to polish the charging port cover.

[0024] Preferably, the polishing assembly includes a polishing frame, a polishing head, an adjusting block, and a transmission block; the polishing frame is disposed on the base frame, the polishing head is mounted on the polishing frame, the polishing head includes a fixed block and a movable block, the fixed block is fixedly mounted on one end of the polishing frame, and the movable block is slidably mounted on the other end of the polishing frame; the adjusting block is disposed between the movable block and the fixed block and is hinged to both the movable block and the fixed block respectively, the adjusting block is connected to a movable polishing block through the transmission block, and the movable polishing block and the polishing head form a polishing section with varying curvature to adapt to the curvature distribution data of the charging port cover.

[0025] Preferably, the transmission component is an elastic component.

[0026] Preferably, the adsorption device includes a plurality of adsorption ports arranged in a ring array, each of the adsorption ports being equipped with a solenoid valve, and the plurality of solenoid valves being opened or closed based on a partitioned geometric model.

[0027] The beneficial effects of this invention are as follows:

[0028] This application breaks through the technical bottleneck of traditional fixed-parameter grinding by using a curvature-adaptive dynamic processing system, achieving high precision for complex curvature surfaces and ensuring the high gloss smoothness requirements of the charging port cover. Attached Figure Description

[0029] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0030] Figure 1 This is a flowchart of the high gloss smoothness surface processing technology provided in one embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the high gloss smoothness surface processing device provided in one embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the charging port cover structure provided in one embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the grinding head connection structure provided in one embodiment of the present invention;

[0034] Legend: 11. Base frame; 12. Grinding frame; 13. Grinding head; 131. Movable block; 132. Fixed block; 14. Adjusting block; 15. Transmission component; 16. Moving grinding block; 2. Adsorption device; 2. Straight section; 3. Small rounded corner section; 4. Large rounded corner section. Detailed Implementation

[0035] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0036] When polishing existing charging port covers, the need for a perfect fit to the vehicle body and consistent linear height arises. If a uniform polishing method is used, the curvature of the edges, particularly the straight sections and the rounded transition sections, will differ significantly. A fixed polishing method, with its larger curvature in the rounded sections, requires a larger polishing area compared to the straight sections. Since existing polishing tools have a fixed area, it's easy to miss polishing areas in the rounded transition sections, potentially necessitating reprocessing or scrapping. Reprocessing, however, makes it difficult to guarantee consistency with the body's lines and high-gloss finish.

[0037] like Figures 1-4 As shown, a high-gloss smoothness surface processing technology includes the following:

[0038] S1: Obtain the curvature distribution data of the charging port cover edge in real time through three-dimensional laser scanning, and establish a partitioned geometric model including straight segments, small rounded corner segments and large rounded corner segments;

[0039] S2: Based on curvature distribution data, the grinding component adaptively adjusts the grinding area for straight segments, small rounded corner segments, and large rounded corner 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 of the segment, the larger the wrapping area of ​​the grinding component, thus 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 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, avoid slippage during grinding, and thus make the edge linearity consistent.

[0040] S3: Based on the partitioned geometry model, the grinding component is adjusted to first grind straight segments, then small rounded segments, and finally large rounded segments, following this grinding method.

[0041] In summary, the curvature-adaptive dynamic processing system breaks through the technical bottleneck of traditional fixed-parameter grinding, achieving high precision on complex curvature surfaces and ensuring the high gloss smoothness requirements of the charging port cover.

[0042] Based on the above-described embodiment of partitioned polishing, partitioned polishing leads to uneven heat accumulation. Specifically, heat is concentrated in straight sections, while small and large rounded corner sections, due to their arc structure, exhibit difficulties in heat dissipation.

[0043] In one embodiment, when adjusting the pressure of the grinding component in step S2, the grinding movement speed is adjusted in the opposite direction according to the real-time radius of curvature, wherein:

[0044] a) In the straight section area, the first pressure level is matched with the first speed range, employing 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 grinding passes, and shortening the friction time, thereby reducing heat accumulation. Low speed reduces the grinding head's moving speed, avoiding excessive instantaneous temperature rise due to rapid friction, significantly reducing heat concentration in the straight section, preventing deformation, and ensuring consistent linearity.

[0045] b) The small rounded corner area adopts the second pressure level matched with the second speed range, using a low-pressure, high-speed strategy. The low pressure reduces contact pressure and avoids local heat accumulation due to poor heat dissipation. The high speed increases the movement speed of the grinding head, shortens the single contact time, and uses high-speed airflow to assist in heat dissipation, reducing the heat retention time in the rounded section, effectively improving the heat dissipation problem of the small rounded corner, avoiding microscopic surface defects, and maintaining the smoothness of the rounded transition area;

[0046] c) The large rounded corner section adopts a third pressure level matched with a third speed range, i.e., a medium-pressure, medium-speed strategy. This balances grinding pressure and movement speed, dynamically matching the heat generation and dissipation rates. Medium pressure avoids localized over-grinding, while medium speed ensures grinding coverage. Simultaneously, continuous and uniform frictional heat distribution maintains temperature stability. This prevents missed or over-grinding due to abrupt changes in curvature in the large rounded corner section, ensuring a smooth transition with the straight sections.

[0047] In summary, by dynamically matching pressure and speed, the temperature rise of each section is controlled within a reasonable range, avoiding material deformation or surface damage caused by heat accumulation. Straight sections reduce the number of repeated grinding passes, while large / small fillet sections achieve thermal balance through speed control, significantly reducing the overall temperature gradient. The curvature adaptive strategy ensures uniform grinding across straight, small, and large fillet sections, eliminating unpolished areas. The high-gloss finish provides a natural linear transition, meeting the stringent tolerance requirements of vehicle assembly.

[0048] Since the edge of the charging port cover is being processed, the stable clamping of the charging port cover plays a crucial role in the processing quality. Furthermore, the high-pressure grinding on the straight section causes a sudden increase in normal shear force, and the low-speed movement prolongs the single-point action time. The combination of these two factors can easily lead to workpiece vibration and edge micro-cracks.

[0049] In one embodiment, a negative pressure adsorption charging port cover is used to generate negative pressure adsorption control parameters based on the geometric model established in step S1. When grinding the straight section, the adsorption area is expanded to A1 and the adsorption pressure Q1 and the grinding pressure P1 satisfy Q1 / P1≥3:1. In this way, the adsorption pressure is at least 3 times the grinding pressure, forming a constraint field to suppress the vertical shear vibration generated in the high pressure direction. At the same time, the adsorption area A1 is expanded to increase the contact area and disperse stress, avoiding excessive local pressure that could lead to surface indentation.

[0050] It is easy to match the second pressure level (low speed) with the second speed range (high speed) for small rounded corner sections. However, low-speed grinding reduces the contact stability between the tool and the workpiece, leading to over-polishing of edges and deformation of thin-walled areas.

[0051] In one embodiment, when grinding the small rounded corner segment, the adsorption area is reduced to A2 to match the radius of curvature of the small rounded corner segment, and the adsorption area is reduced to match the arc contour, so as to avoid the adsorption edge from exceeding the effective contact surface of the workpiece, which may lead to air leakage or sudden change in local stress.

[0052] The ratio of adsorption pressure to workpiece is set to 1:1 < Q2 / P2 < 2:1, ensuring the adsorption pressure is slightly higher than the grinding pressure without excessively constraining the workpiece. During high-speed movement, the adsorption system adjusts the negative pressure distribution in real time, ensuring the adsorption force direction is always aligned with the tangential direction of the grinding head's movement trajectory, thus counteracting tool deviation caused by centrifugal force. By reducing the concentrated area of ​​adsorption A2, the coverage of thin-walled regions is minimized, while maintaining precise constraint of the adsorption pressure Q2 on key stress points, thus avoiding distributed deformation caused by large-area adsorption.

[0053] Q2 / P2 > 1 ensures that the adsorption system always provides a positive constraint force, suppressing pressure fluctuations caused by tool vibration during high-speed polishing. The reduced adsorption area A2 improves the pressure uniformity of the edge area, allowing the polishing pressure P2 to be evenly transmitted on the arc surface, eliminating the risk of local over-polishing.

[0054] Due to the continuous change in the radius of curvature of the large rounded corner section, the fixed adsorption area will cause the adsorption surface to decrease in the area of ​​curvature change and the workpiece to become less adherent. Local air leakage will cause fluctuations in clamping force. The fixed adsorption area cannot adapt to the curvature change, resulting in uneven pressure distribution. Tensile stress concentration will occur at the curvature change, causing surface wrinkles or subsurface damage.

[0055] In one embodiment, during the polishing of the large rounded corner section, the adsorption area is dynamically adjusted as A3 = A1·(1-ΔR / R0), where ΔR is the change in radius of curvature and R0 is the reference radius. When the curvature increases (ΔR>0), the adsorption area A3 is reduced proportionally to reduce excessive coverage of the low curvature area, avoid air leakage caused by the adsorption edge being suspended, and concentrate the adsorption pressure on the high curvature area (the section with a smaller radius of curvature) to enhance the constraint force on the abrupt change area.

[0056] When the curvature decreases (ΔR<0): the adsorption area A3 expands, increasing the coverage of the gently curvature area, dispersing pressure to prevent local pressure from exceeding the limit, and the boundary of the adsorption surface extends smoothly with the curvature, eliminating the gap in the fit; the dynamic adsorption area ensures that the pressure per unit area is inversely related to the radius of curvature (high pressure in high curvature areas and low pressure in low curvature areas), offsetting the difference in normal force caused by curvature changes, and the adsorption system matches the workpiece surface deformation in real time through area adjustment, suppressing the accumulation of elastic deformation caused by grinding pressure.

[0057] During the high-pressure, low-speed grinding process on straight sections, the continuous friction and heat generation can lead to: excessively high local temperatures (>75℃), causing softening of metal materials, damage to the micro-grain structure, reduced surface hardness and corrosion resistance, and thermal expansion differences between high-temperature and non-high-temperature areas, resulting in deviations in the linear height of the charging port cover. Furthermore, materials such as aluminum alloys are prone to oxidation and discoloration at high temperatures, affecting the visual consistency of the high-gloss surface.

[0058] In one embodiment, S301: Integrate an infrared temperature measurement module to monitor the temperature of the processing area in real time and establish a dynamic temperature field model, scan the processing area, generate a temperature distribution heat map, locate high temperature points, and integrate parameters such as material thermal conductivity coefficient and environmental heat dissipation conditions to predict the temperature evolution trend and predict overheating risk areas in advance.

[0059] S302: When machining on a straight section, if the monitored temperature is >75℃, the compensation mechanism is automatically triggered to dynamically reduce the first pressure level (originally high pressure) in a gradient manner, reducing the frictional energy input per unit area, directly suppressing the temperature rise, and simultaneously increasing the first speed range (originally low speed), shortening the dwell time of the grinding head in the high-temperature zone, accelerating heat dissipation. The pressure reduction is positively correlated with the temperature exceeding the limit, and the speed increase is matched with the pressure reduction to ensure a constant material removal rate. After the pressure-speed adjustment, the temperature is continuously monitored until it falls back to the safe threshold (<65℃), and the initial parameters are gradually restored.

[0060] A high-gloss surface processing device includes an adsorption component that generates a uniform negative pressure field in the grinding zone through the adsorption port at the bottom of the base frame, stably adsorbing the charging port cover onto the processing plane to ensure that the workpiece does not shift or vibrate during the grinding process. The grinding component drives the grinding head through a multi-degree-of-freedom robotic arm at the top of the base frame to perform adaptive curvature grinding on the edge of the charging port cover according to a preset path (straight segment, small rounded corner segment, large rounded corner segment), while dynamically adjusting the pressure and speed.

[0061] In addition, sensors are integrated to collect pressure, temperature and position data in real time, which are fed back to the control system to dynamically optimize the adsorption force and polishing parameters, forming a closed loop of "perception-decision-execution".

[0062] In one embodiment, the grinding assembly includes a grinding frame, a grinding head, and an adjusting block. Both the grinding head and the adjusting block are equipped with independent grinding parts for surface finishing. The grinding frame serves as a rigid support body, fixed on a base frame, providing a stable motion track and mechanical bearing foundation. A fixed block is rigidly fixed to one end of the grinding frame, serving as a reference anchor point for the grinding section. A movable block is connected to the other end of the grinding frame via a slide rail, allowing it to slide along the axial direction of the grinding frame to adjust the length and curvature of the grinding section. The adjusting block is hinged between the fixed block and the movable block, forming a linkage mechanism.

[0063] Several adjusting blocks are hinged between the movable block and the fixed block, and these adjusting blocks are independent. When the movable block and the fixed block move relative to each other, the adjusting blocks move towards the axis and drive the transmission component to generate tension, which pulls the moving grinding block and the grinding head to move relative to each other. The upper and lower ends of the moving grinding block form a grinding section with variable curvature between them and the movable block and the fixed block. In particular, the end of the movable block and the fixed block adjacent to the moving grinding block is an arc structure. As the moving distance of the moving grinding block changes, the curvature between the moving block and the movable block and the fixed block also changes. The greater the moving distance of the movable block, the more concave the grinding section becomes. This allows for a larger area of ​​the charging port cover to be covered, ensuring that no area is missed when grinding small and large rounded corners, thus ensuring the overall line and appearance are consistent.

[0064] Furthermore, the transmission components should be made of rigid structures to avoid the use of elastic transmission components, which would result in insufficient contact with the workpiece due to elasticity when the moving grinding block is processing it. Rigid structures, such as metal rods, can not only enable the movement of the moving grinding block, but also generate sufficient contact support force when the moving grinding block is grinding, thus ensuring the grinding effect.

[0065] In one embodiment, the adsorption device includes several adsorption ports, which are evenly distributed in a ring along the outer edge of the polishing area, covering all curvature sections (straight segments, small rounded corner segments, and large rounded corner segments) of the charging port cover. Each adsorption port is equipped with an independent solenoid valve. Based on the partition geometric model generated in step S1, the adsorption port group corresponding to the current polishing area is identified, and only the relevant solenoid valve is opened.

[0066] Linear segment adsorption: Open multiple adsorption ports directly below and adjacent to the linear segment, such as 6-8 consecutively, to form a wide adsorption surface and enhance rigid constraint.

[0067] Arc-shaped adsorption: Based on the radius of curvature of the arc, selectively open the adsorption ports within the corresponding arc, such as 3-4 ports for small rounded corners and 5-6 ports for large rounded corners, to avoid air leakage due to the edge adsorption ports being suspended.

[0068] Transition zone coordination: Adsorption ports in adjacent regions open and close in a gradient manner to ensure a smooth transition of adsorption force and eliminate sudden pressure changes.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-gloss smoothness surface processing technology, characterized in that, Includes the following: S1: Obtain the curvature distribution data of the charging port cover edge in real time through three-dimensional laser scanning, and establish a partitioned geometric model including straight segments, small rounded corner segments and large rounded corner segments; S2: Based on curvature distribution data, the grinding component is adaptively adjusted to grind the area of ​​straight segments, small rounded corners, and large rounded corners; in step S2, when adjusting the pressure of the grinding component, the grinding movement speed is adjusted in the opposite direction according to the real-time curvature radius, wherein: a) The straight section area adopts the first pressure level matched with the first speed range; b) The small rounded corner section area uses the second pressure level to match the second speed range; c) The large rounded corner section area adopts the third pressure level matched with the third speed range; The first pressure level > the third pressure level > the second pressure level, corresponding to the first speed range < the third speed range < the second speed range; S3: Based on the partitioned geometric model, the grinding components are adjusted to grind the straight section, small rounded corner section, and large rounded corner section in sequence; using the negative pressure suction charging port cover, negative pressure adsorption control parameters are generated based on the geometric model established in step S1; when grinding the straight section, the adsorption area is expanded to A1 and the adsorption pressure Q1 and the grinding pressure P1 satisfy Q1 / P1≥3:1; S301: Integrate 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 machining on a straight section, if the temperature exceeds 75℃, the pressure compensation mechanism is triggered, which dynamically reduces the first pressure level and increases the first speed range.

2. The high-gloss smoothness surface processing technology according to claim 1, characterized in that, When polishing small rounded corner sections, the adsorption area is reduced to A2 and the adsorption pressure Q2 and the polishing pressure P2 satisfy 1:1 < Q2 / P2 < 2:

1.

3. The high-gloss smoothness surface processing technology according to claim 2, characterized in that, When polishing the large rounded corner section, the adsorption area is dynamically adjusted as A3=A1·(1-ΔR / R0), where ΔR is the change in the radius of curvature and R0 is the reference radius.

4. The high-gloss surface processing technology according to claim 1 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 disposed in the lower part of the base frame and communicates with the polishing area, and is used to adsorb the charging port cover; the polishing component is disposed in the upper part of the base frame and extends downward to the polishing area to polish the charging port cover.

5. The high-gloss smoothness surface processing technology according to claim 4, characterized in that, The polishing assembly includes a polishing frame, a polishing head, an adjusting block, and a transmission block. The polishing frame is disposed on the base frame, and the polishing head is mounted on the polishing frame. The polishing head includes a fixed block and a movable block. The fixed block is fixedly mounted on one end of the polishing frame, and the movable block is slidably mounted on the other end of the polishing frame. The adjusting block is disposed between the movable block and the fixed block and is hinged to both the movable block and the fixed block. The adjusting block is connected to a movable polishing block through the transmission block. The movable polishing block and the polishing head form a polishing section with varying curvature to adapt to the curvature distribution data of the charging port cover.

6. The high-gloss smoothness surface processing technology according to claim 5, characterized in that, The adsorption assembly includes several adsorption ports arranged in a ring array. Each adsorption port is equipped with a solenoid valve, and the solenoid valves are opened or closed based on a partitioned geometric model.

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