Superposition spraying control method based on self-adaption semi-curing interface

Abstract

The invention relates to the technical field of surface coating, in particular to a self-adaptive semi-cured interface superposition spraying control method which comprises the following steps: S1, generating spraying path parameters according to the surface curvature of a workpiece and the distance between adjacent stations; s2, workpiece offset data are obtained in real time through a visual positioning system, three-dimensional coordinate compensation data are generated based on an image matching algorithm, and when the offset exceeds a preset threshold value, real-time re-planning of a spraying path is triggered; s3, multiple groups of nozzles are controlled to execute in an alternate spraying mode: after a first layer of material is sprayed at the first station, irradiation is performed for 0.5-2 s by adopting 50-100 mW / cm < 2 > UV intensity, and a semi-cured layer with the light curing rate of 70%-85% and the thickness of 5-20 microns is formed; s4, after the conveying belt moves to a second station, a first layer of material is sprayed on the second station and partially cured, a second layer of material is sprayed on the first station, and the light curing rate is larger than or equal to 95%; s5, the steps S3-S4 are cycled to complete multi-layer spraying; and S6, dynamically adjusting the doping proportion of the nano conductive particles in the spraying material according to the environment humidity.

Description

Technical Field

[0001] The present invention relates to the technical field of surface coating, and particularly relates to an adaptive semi-cured interface superposition spraying control method.

Background Art

[0002] Currently, in the field of precision manufacturing, complex curved surface workpieces (such as fan blades, equipment casings, etc.) have multiple conflicting requirements for coating performance: both ensuring the coating thickness uniformity (accuracy at the level of ±5μm) and achieving high bonding strength (≥15MPa) and dynamic anti-static function (adjustable from 10 6 -10 9 Ω·m).

[0003] The prior art has the following technical problems:

[0004] 1. Traditional single-material full-curing process: Using a single epoxy resin or polyurethane material, a coating is formed through full curing (light curing rate > 95%). Due to the single material, the layers are only combined by physical adsorption, resulting in low bonding strength (≤5MPa), and the electrostatic protection depends on a fixed doping ratio. When the environmental humidity fluctuates, the surface resistance volatility exceeds ±35%, making it difficult to meet the stability requirements of high-precision equipment.

[0005] 2. Two-material no-interface control process: Although a two-material system of epoxy resin + polyurethane is used, each layer is fully cured, lacking a gradient curing interface design. Experiments show that the boundary bonding force of such a process is only 7MPa, and due to the lack of molecular chain entanglement in the semi-cured layer, coating peeling is likely to occur in the area of sudden curvature change (such as the edge of the fan blade), and the peeling rate in the 2000-hour reliability test reaches 3 times per piece.

[0006] 3. Dynamic doping no-synergistic curing process: Some technologies attempt to improve the anti-static performance by dynamically adjusting the doping ratio of conductive particles, but a single-band UV curing (395nm) is used for unified treatment, resulting in over-curing of the surface layer and insufficient cross-linking in the deep layer. Tests show that although such a process can reduce the humidity response delay, the interlayer shear strength is only 10MPa, and the material waste rate is as high as 22%.

[0007] In view of the above technical problems, the present invention is specifically studied and proposed.

Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide an adaptive semi-cured interface superposition spraying control method to achieve high uniformity, high-strength bonding, dynamic anti-static and efficient production of complex curved surface coatings.

[0009] To solve the above technical problems, the present invention proposes an adaptive semi-cured interface superposition spraying control method, including the following steps:

[0010] S1. Generate spraying path parameters, including: generating multiple spraying stations according to the size of the workpiece, and generating spraying path parameters according to the surface curvature of the workpiece and the spacing between adjacent stations. The ratio of the moving speed of the conveyor belt to the lateral moving speed of the nozzle is 1:1.5 - 1:1.2, and the spraying pressure at the intersection of adjacent stations is reduced by 20% - 40%.

[0011] S2. Real-time obtain the workpiece offset data through the vision positioning system, generate three-dimensional coordinate compensation data based on the image matching algorithm, and trigger real-time replanning of the spraying path when the offset exceeds the preset threshold.

[0012] S3. Control multiple groups of nozzles to execute in an alternating spraying mode: after spraying the first layer of material at the first station, irradiate with a UV intensity of 50 - 100 mW / cm 2 for 0.5 - 2 s to form a semi-cured layer with a light curing rate of 70% - 85% and a thickness of 5 - 20 μm.

[0013] S4. After the conveyor belt moves to the second station, correct the nozzle path so that the interval between the two station boundaries is 0.5 - 2 mm, and execute synchronously: spray the first layer of material at the second station and partially cure it, and spray the second layer of material at the first station and cure it with a UV intensity of 150 - 200 mW / cm 2 until the light curing rate ≥ 95%.

[0014] S5. Repeat steps S3 - S4 to complete multi-layer spraying, and the interlayer bonding strength ≥ 15 MPa.

[0015] S6. Dynamically adjust the doping ratio of nano-conductive particles in the spraying material by 0.1% - 1.5% according to the environmental humidity to control the surface resistance value within 10 6 -10 9 Ω·m.

[0016] An adaptive semi-cured interface superposition spraying control method as described above is applicable to the following application scenarios:

[0017] The spraying path planning includes:

[0018] Regard the curved surface with a surface drop ≤ 2 cm as a plane for path planning;

[0019] For the curved surface with a radius of curvature > 50 mm, use the piecewise linear approximation algorithm to generate the spraying trajectory;

[0020] When the online thickness detection device measures that the coating thickness deviation exceeds ±5%, adjust the nozzle flow rate and moving speed within 0.5 s, and the control accuracy is ±1.5 μm.

[0021] An adaptive semi-cured interface superposition spraying control method as described above is applicable to the following application scenarios:

[0022] The curing control includes:

[0023] For the first-layer partial curing, a 395-nm wavelength UV light source is used to preferentially cure the surface layer;

[0024] For the secondary curing, a 365-nm wavelength UV light source is used to strengthen the deep cross-linking;

[0025] The viscosity of the semi-cured layer is controlled to 2000 - 5000 Pa·s by adjusting the ratio of the spraying speed to the UV irradiation intensity.

[0026] A spraying control method based on an adaptive semi-cured interface superposition as described above is applicable to the following application scenarios:

[0027] The anti-static regulation includes:

[0028] When the environmental humidity RH > 70%, the doping ratio of carbon nanotubes is increased to 0.8% - 1.2%;

[0029] For substrates with a dielectric constant ε ≤ 3, the proportion of conductive particles is adjusted in real time to make the resistance deviation ≤ ±15%;

[0030] For non-polar substrates, the semi-curing rate is reduced to 60% - 75% to enhance the adhesion.

[0031] A spraying control method based on an adaptive semi-cured interface superposition as described above is applicable to the following application scenarios:

[0032] The multi-substrate adaptability treatment includes:

[0033] For porous substrates, the distance between the nozzle and the workpiece is increased by 0.3 - 0.8 mm and the material flow rate is increased by 10% - 20%;

[0034] For wood and plastic substrates, the material viscosity threshold of 50 - 200 mPa·s and the UV band of 365 - 405 nm are dynamically matched;

[0035] The paint residue amount on the surface of the fixture is monitored in real time, and when the residue amount > 0.1 g / cm 2 a cleaning warning is triggered and the spraying pressure of the adjacent station is reduced.

[0036] A spraying control method based on an adaptive semi-cured interface superposition as described above is applicable to the following application scenarios:

[0037] The dual-material interface bonding is achieved by the following method:

[0038] The first-layer epoxy resin-based material contains unreacted glycidyl ether groups;

[0039] The second-layer polyurethane-based material contains isocyanate groups;

[0040] During secondary curing, the active groups in the semi-cured layer form covalent bonds with the second-layer material.

[0041] An adaptive semi-cured interface superposition spraying control method as described above is applicable to the following application scenarios:

[0042] Environmental parameter compensation includes:

[0043] Real-time collection of environmental temperature, humidity and air flow velocity data;

[0044] Adjust the conductive particle ratio by 0.2% correspondingly according to the humidity change gradient ΔRH = 10%;

[0045] When the air flow velocity > 2 m / s, the spraying pressure is increased by 10% - 15%.

[0046] An adaptive semi-cured interface superposition spraying control method as described above is applicable to the following application scenarios:

[0047] The nozzle maintenance control includes:

[0048] Execute the nozzle cleaning step during the spraying gap, and use 0.5 - 0.8 MPa air pressure to remove the residual coating;

[0049] Automatically set the cleaning cycle according to the material viscosity, and the trigger condition is a viscosity value of 200 - 500 mPa·s.

[0050] An adaptive semi-cured interface superposition spraying control method as described above, the workpiece includes the synchronous processing of the housing of household appliances or electronic devices or lightweight double-sided coated workpieces.

[0051] An adaptive semi-cured interface superposition spraying control method as described above is applicable to the following application scenarios:

[0052] Preparation of a dust-proof coating for a curved surface workpiece of a household appliance;

[0053] Spraying of an anti-static film layer on the housing of an electronic device;

[0054] Synchronous processing of lightweight double-sided coated workpieces.

[0055] Compared with the prior art, an adaptive semi-cured interface superposition spraying control method of the present invention has the following advantages:

[0056] 1. Through the present invention, when spraying complex curved surface workpieces, the coating thickness deviation ≤ ±5 μm, the coating can be more uniform, and the material waste rate can be reduced by 40%.

[0057] 2. Through visual dynamic compensation, the present invention can correct the workpiece offset in real time. When the offset exceeds the threshold, the path is replanned, and the spraying misalignment rate is reduced by 90%, which can improve the dynamic positioning compensation and spraying accuracy.

[0058] 3. By means of alternating gradient curing: after spraying at the first station, the curing rate of 395nm UV reaches 70%-85%, and the second station operates synchronously and the secondary curing rate of 365nm UV is ≥95%, so that the bonding strength can be higher.

[0059] 4. Through dynamic anti-static regulation, the resistance value on the product surface is maintained at 10 6 -10 9 Ω·m, thereby further preventing static electricity.

Description of the Drawings

[0060] The following further elaborates on the specific implementation manners of the present invention in conjunction with the drawings, where:

[0061] Figure 1 is the flowchart of the dual-material superposition spraying control method based on the adaptive semi-cured interface of the present invention.

[0062] Figure 2 is the humidity-doping-resistance regulation flowchart in the invention.

[0063] Figure 3 is the non-polar substrate enhancement control logic diagram of the present invention.

[0064] Figure 4 is the structural schematic diagram of the fan blade of the present invention.

Specific Embodiment

[0065] The following elaborates on the implementation manners of the present invention in detail in conjunction with the drawings.

[0066] As Figures 1 - 4 shown, Figure 4 in it, A represents the spraying station of the fan blade, and B represents the intersection of the two spraying stations.

[0067] The present invention includes a superposition spraying control method based on an adaptive semi-cured interface, including the following steps:

[0068] S1. Generate spraying path parameters, including: generating multiple spraying stations according to the size of the workpiece, and generating spraying path parameters according to the surface curvature of the workpiece and the distance between adjacent stations. The ratio of the conveyor belt moving speed to the transverse moving speed of the nozzle is 1:1.5 - 1:1.2. The spraying pressure at the intersection of adjacent stations is reduced by 20% - 40%, and the material flow rate in the boundary area is reduced by 15% - 30%. In this step, the path planning driven by surface curvature: control the ratio of the conveyor belt moving speed to the transverse moving speed of the nozzle at 1:1.5 - 1:1.2, and calculate the coating coverage of the unit curved surface in combination with the fluid mechanics model to ensure the dynamic balance of the spraying amount in the concave area (such as the root of the fan blade) and the convex area (the tip of the blade). Boundary pressure and flow rate regulation: the spraying pressure at the junction of adjacent stations is reduced by 20% - 40%, and the material flow rate is reduced by 15% - 30%. Optimize the boundary layer flow field distribution based on the Navier - Stokes equation to avoid paint splashing and accumulation. Therefore, through this step, the coating thickness deviation of complex curved surface workpieces (such as fan blades) is ≤ ±5μm, the coating can be more uniform, and the material waste rate can be reduced by 40%.

[0069] S2. Real - time obtain the workpiece offset data through the vision positioning system, generate three - dimensional coordinate compensation data (accuracy ±0.1mm) based on the image matching algorithm, and trigger the real - time replanning of the spraying path when the offset exceeds the preset threshold. In this step, identify the edge contour of the workpiece and the fixture reference mark through the SIFT feature extraction algorithm to generate a three - dimensional coordinate compensation matrix. When the workpiece is offset due to thermal deformation or vibration, the nozzle trajectory is corrected in real time through affine transformation to ensure that the spraying path matches the surface geometry. Therefore, in this step, the workpiece offset compensation accuracy reaches ±0.1mm, the spraying misalignment rate is reduced by 90%, and the dynamic positioning compensation and spraying accuracy can be improved.

[0070] S3. Control multiple groups of nozzles to execute in an alternating spraying mode: after spraying the first layer of material at the first station, irradiate with a UV intensity of 50 - 100mW / cm 2 for 0.5 - 2s to form a semi - cured layer with a light curing rate of 70% - 85% and a thickness of 5 - 20μm.

[0071] S4. After the conveyor belt moves to the second station, correct the nozzle path so that the interval between the two stations at the boundary is 0.5 - 2mm, and execute synchronously: spray the first layer of material at the second station and partially cure it, and spray the second layer of material at the first station and cure it with a UV intensity of 150 - 200mW / cm 2 until the light curing rate ≥ 95%.

[0072] S5. Repeat steps S3 - S4 to complete multi - layer spraying, and the inter - layer bonding strength ≥ 15MPa.

[0073] In S3 and S4, 70%-85% of the photocuring rate in the first layer retains unreacted acrylate double bonds (epoxy resin) or isocyanate groups (polyurethane). During secondary curing, the active groups in the second layer material copolymerize with the residual groups in the semi-cured layer to form an interpenetrating network (IPN) structure connected by covalent bonds. For UV dual-band cooperative curing, 395 nm cures the surface layer, and 365 nm penetrates the semi-cured layer to initiate deep cross-linking, enhancing the entanglement density of interfacial molecular chains.

[0074] Through S3 and S4, the interlayer bonding strength can be significantly enhanced. The interlayer bonding strength ≥ 12 MPa, compared with the traditional process ≤ 8 MPa, and the anti-peeling performance is improved by 50%.

[0075] S6. Dynamically adjust the doping ratio of nano-conductive particles (particle size 10-50 nm, zinc oxide / carbon nanotubes) in the sprayed material according to the environmental humidity, with the doping ratio ranging from 0.1% to 1.5%, so as to control the surface resistance value within 10 6 -10 9 Ω·m. Based on the real-time adjustment of the environmental humidity (RH), the doping ratio of nano-zinc oxide or carbon nanotubes is adjusted, so that a 10% change in ΔRH corresponds to a 0.2% ratio adjustment. Proton conduction channels are formed by the adsorption of water molecules on the surface hydroxyl groups (-OH) of the conductive particles.

[0076] Control the threshold of the conductive network through the percolation theory model Percolation Theory to ensure that when the humidity increases, RH > 70%, the doping ratio is increased to 0.8% - 1.2% to maintain the connectivity of the percolation path.

[0077] In this step, the surface resistance value of the fan blade can be controlled within the range of 10 6 -10 9 Ω·m, and the resistance deviation under humidity fluctuations ≤ ±20%.

[0078] Comparative Example 1 (using the traditional single-material full-curing process)

[0079] The technical solution is as follows:

[0080] 1. Use a single epoxy resin material without an alternating spraying step;

[0081] 2. After spraying, directly cure with a UV intensity of 200 mW / cm 2 at 365 nm until complete curing, that is, the photocuring rate > 95%;

[0082] 3. Without doping with dynamic conductive particles, fixedly add 0.5% carbon nanotubes;

[0083] 4. Use mechanical positioning with a fixed spraying path.

[0084] The test results are as follows in the table:

[0085]

[0086] Comparative Example 2 (Dual-material process without semi-cured interface)

[0087] The technical solution is as follows:

[0088] 1. Use epoxy resin + polyurethane dual materials;

[0089] 2. After each layer is sprayed, it is fully cured, that is, the photocuring rate > 95%;

[0090] 3. Conductive particles are statically doped (0.8% zinc oxide);

[0091] 4. Visual positioning is adopted but there is no path replanning (compensation accuracy ±0.3 mm). The test results are as follows in the table:

[0092] Index Case of the present invention Comparative Example 2 Improvement effect Boundary bonding force (MPa) (MPa) 10 7 +43％ Tip coating peeling rate (times) 2 / 2000h 3 / 2000h Reliability improved by 33% Spraying misalignment rate ≤3％ 5％ Precision improved by 40% Energy consumption (kW·h / unit) 1 1.5 Reduced by 33%

[0093] Comparative Example 3 (Dynamic doping process without gradient curing)

[0094] The technical solution is as follows:

[0095] 1. Adopt dynamic conductive particle doping (0.1% - 1.5% zinc oxide);

[0096] 2. Single-band UV curing (395 nm, the photocuring rate is unified to 85%);

[0097] 3. There is no alternating spraying, and single-station operation;

[0098] 4. The spraying path planning has no curvature adaptation.

[0099] The test results are as follows in the table:

[0100] Index Case of the present invention Comparative Example 3 Improvement effect Curved surface thickness uniformity (μm) ±8 ±12 +33％ Interlaminar shear strength (MPa) 14 10 +40％ Humidity response delay (seconds) ≤2 3 Response speed improved by 33% Material waste rate 15％ 22％ Reduced by 32%

[0101] Conclusion: Through the above comparative experiments, it can be seen that compared with the prior art, the present invention:

[0102] 1. The interlayer bonding strength is increased by 40% - 50% (chemical bonding vs physical adsorption);

[0103] 2. The anti-static stability is increased by 33% - 43% (dynamic percolation vs static doping);

[0104] 3. The production efficiency is increased by 33% - 40% (alternating stations vs single station);

[0105] 4. The coating accuracy is increased by 33% - 40% (visual compensation + curvature adaptation vs mechanical positioning).

[0106] As a further solution of this embodiment, the spraying path planning includes:

[0107] For a curved surface with a surface drop ≤ 2 cm, it is regarded as a plane for path planning. The technical principle is as follows: 1. Drop threshold setting: Through hydrodynamic simulation verification, when the surface drop of the curved surface ≤ 2 cm, the surface tension of the coating is sufficient to cover the concave and convex surfaces, and no complex three-dimensional path is required. 2. Pressure-flow coupling control: Adjust the boundary layer parameters according to the Reynolds number (Re = 50 - 200) to suppress the generation of eddy currents.

[0108] Taking the blade of a household ceiling fan as an example:

[0109] 1. Taking the blade (the maximum surface drop is 1.8 cm) as the object, discretize its curved surface into a plane grid with a grid size of 5 mm × 5 mm;

[0110] 2. Generate a spraying path based on the plane grid, and set the ratio of the transverse speed of the nozzle to the speed of the conveyor belt to 1:1.3;

[0111] 3. In the root rib area of the blade and the edge area of the blade (i.e., the area with a drop < 2 cm), the spraying pressure is reduced by 30%, and the material flow rate is reduced by 20%.

[0112] Through the above steps,

[0113] 1. The spraying efficiency can be increased by 35%. Compared with the traditional NURBS curved surface algorithm, the planarization process reduces the path planning calculation amount by 70%.

[0114] 2. Improvement of coating uniformity: The thickness deviation in the root and edge areas of the blade is reduced from ±25 μm to ±8 μm;

[0115] 3. The material waste rate is reduced by 28%: The boundary flow control reduces splashing, and the coating utilization rate is increased from 82% to 90%.

[0116] For a curved surface with a radius of curvature > 50 mm, a piecewise linear approximation algorithm is used to generate a spraying trajectory. In this step, the technical principle is as follows:

[0117] 1. Piecewise criterion: Determine the optimal piecewise length according to the relationship between the radius of curvature and the coating diffusion rate (formula: L = 0.2√(R·μ / ρv), where μ is the viscosity, ρ is the density, and v is the flow velocity);

[0118] 2. Dynamic pressure regulation: Based on the Bernoulli equation, reduce the pressure in the area where the curvature increases to balance the flow velocity.

[0119] Still taking the blade of a household ceiling fan as an example,

[0120] 1. For the edge of the blade (radius of curvature 60 mm), divide the curved surface into 10 linear micro-elements, each with a length of 6 mm;

[0121] 2. The continuous spraying trajectory is generated by using the fifth-order polynomial interpolation algorithm, and the ratio of the transverse speed of the nozzle to the conveyor belt speed is set to 1:1.4;

[0122] 3. In the region of sudden curvature change (R = 55 mm → 65 mm), the spraying pressure is dynamically reduced by 25% - 35%.

[0123] Through the above steps:

[0124] 1. The trajectory accuracy can be improved by 40%: the piecewise approximation makes the path fitting error ≤ 0.05 mm (the error of the traditional B-spline method ≥ 0.15 mm);

[0125] 2. The spraying stability is enhanced: the coating thickness fluctuation in the region of sudden curvature change is reduced from ±15 μm to ±5 μm;

[0126] 3. Computational resources are saved: the path planning time is shortened from 12 s / piece to 3 s / piece.

[0127] When the on-line thickness detection device measures that the coating thickness deviation exceeds ±5%, the nozzle flow rate and moving speed are adjusted within 0.5 s, and the control accuracy is ±1.5 μm. The principle of adjusting the nozzle flow rate and moving speed is as follows:

[0128] 1. Closed-loop control model: Establish the thickness-flow rate-speed transfer function: K_p / (T_is + 1)e^{-T_ds}, where K_p = 0.8, T_i = 0.2, T_d = 0.05;

[0129] 2. Multi-parameter coordination: Decouple the coupling effect of the flow rate and speed through the Jacobian matrix to ensure the adjustment stability.

[0130] This embodiment solves the contradiction that it is difficult to have both high efficiency and high precision in traditional spraying through the technical combination of intelligent path planning + real-time closed-loop control, and is particularly suitable for curved surface products with a drop of less than 2 cm.

[0131] As a further solution of this embodiment, the curing control includes:

[0132] For the first-layer partial curing, a UV light source with a wavelength of 395 nm is used to preferentially cure the surface layer.

[0133] For the secondary curing, a UV light source with a wavelength of 365 nm is used to strengthen the deep cross-linking.

[0134] The viscosity of the semi-cured layer is controlled to 2000 - 5000 Pa·s by adjusting the ratio of the spraying speed to the UV irradiation intensity.

[0135] The steps and principles of the first-layer spraying and partial curing are as follows:

[0136] 1. Spray an epoxy resin-based material (viscosity 150 mPa·s) at the first station of the conveyor belt, and the ratio of the transverse speed of the nozzle to the speed of the conveyor belt is 1:1.3;

[0137] 2. Use a UV light source with a wavelength of 395 nm and an intensity of 80 mW / cm 2 , and irradiate for 1.5 s to form a semi-cured layer with a photocuring rate of 80% and a thickness of 12 μm;

[0138] 3. Continuously monitor the coating viscosity (through an on-line rheometer) and control it at 3000 Pa·s to ensure interlayer adhesion.

[0139] The steps of the second curing and the second layer spraying are as follows:

[0140] 1. After the conveyor belt moves to the second station, spray a polyurethane-based material (viscosity 220 mPa·s) with a boundary interval of 1.2 mm;

[0141] 2. Switch to a UV light source with a wavelength of 365 nm and an intensity of 180 mW / cm 2 at the first station, and irradiate for 4 s to make the photocuring rate reach 97%;

[0142] 3. Synchronously perform the partial curing operation of step 1 on the second station.

[0143] Through the test of ASTM D4541, in this embodiment, through the second curing method, the interlayer bonding strength can be improved, from 8 MPa in the traditional process to 12 MPa, and the interlayer bonding strength is increased by 48%. And the curing energy consumption is reduced by 35%. The 395 nm wavelength preferentially cures the surface layer and reduces the ineffective irradiation of the deep layer. The total energy consumption is reduced from 1.2 kW·h / m 2 to 0.78 kW·h / m 2 . And through FTIR spectral analysis, the interfacial molecular bonding of this application is strengthened, and the reaction degree between the glycidyl ether group of epoxy resin and the isocyanate group of polyurethane is increased to 92%.

[0144] As Figure 3 Figure 4 shown, as a further solution of this embodiment, the anti-static regulation includes:

[0145] When the environmental humidity RH > 70%, the doping ratio of carbon nanotubes is increased to 0.8% - 1.2%.

[0146] For substrates with a dielectric constant ε ≤ 3, adjust the proportion of conductive particles in real time so that the resistance deviation ≤ ±15%.

[0147] For non-polar substrates, reduce the semi-curing rate to 60% - 75% to enhance the adhesion.

[0148] In this embodiment, it is realized through the following steps:

[0149] Step 1: Real-time Monitoring and Adjustment

[0150] Use a high-precision humidity sensor (±2%RH) to collect the ambient humidity in real time;

[0151] When RH rises from 50% to 80%:

[0152] Parameter Adjustment:

[0153] The doping ratio of carbon nanotubes (CNT) is linearly increased from 0.6% to 1.0% (ΔRH = 10% corresponds to +0.2%);

[0154] The spraying pressure is reduced by 15% (0.25MPa → 0.21MPa);

[0155] Control Response: The adjustment period ≤ 1s, and the opening error of the flow valve < ±3%.

[0156] Technical Principle:

[0157] Humidity-Doping Model:

[0158] w CNT = 0.6% + 0.04 - (RH - 50%)

[0159] When the humidity increases, water molecules are adsorbed on the surface of CNT to form a proton conduction channel. The principle is the Grotthuss mechanism, and the doping ratio needs to be increased to maintain the connectivity of the percolation network.

[0160] Step 2: Dielectric Constant Feedback Control

[0161] Measure the dielectric constant (ε) of the fan blade substrate:

[0162] ABS plastic: ε = 2.7, initially doped with 0.8% zinc oxide;

[0163] Wood: ε = 3.5, initially doped with 0.5% zinc oxide;

[0164] Dynamic Adjustment:

[0165] When ε ≤ 3, the resistance deviation control ≤ ±10%;

[0166] Feedback Period: 0.5s, and the doping ratio adjustment step size is 0.1%.

[0167] Technical Principle:

[0168] Percolation Threshold Model:

[0169] σ = σ0(φ - φ0)^t (φ0 = 0.5%, t = 1.6)

[0170] By monitoring the resistance value in real time, the volume fraction (φ) of conductive particles is calculated in reverse, and the percolation threshold (φ_c) is dynamically approximated.

[0171] Step 3: Matching surface energy and curing rate

[0172] For the PP plastic fan blade (surface energy 29 mN / m):

[0173] Parameter setting:

[0174] The semi-curing rate is reduced to 65% (default 75%);

[0175] The UV pre-curing time is extended to 2.5 s (395 nm, 60 mW / cm 2 );

[0176] The CNT doping ratio is increased to 1.2%;

[0177] For every 5 mN / m reduction in surface energy, the semi-curing rate is reduced by 5%. The reduction in the semi-curing rate can increase the surface roughness (Ra from 0.2 μm to 0.8 μm), enhancing the bonding force with non-polar substrates through mechanical interlocking.

[0178] Through the above steps, taking the fan blade as an example, the test data is as follows:

[0179] In this embodiment, through the three-in-one dynamic regulation of humidity-dielectric-surface energy, precise control of the anti-static performance of the fan blade is achieved. In a high-humidity environment (RH = 85%), the surface resistance of the fan blade is stable at 10 7 -10 8 Ω·m, and the amount of electrostatically adsorbed dust < 0.1 g / m 2 . Moreover, it has good substrate compatibility. The adaptation time for ABS / PP / wooden fan blades < 3 min, and the adhesion ≥ 4B (ASTM D3359). And the dynamic regulation reduces the excessive use of conductive particles, the material cost is reduced by 25%, the spraying pressure is adjusted adaptively, and the energy consumption of the air compressor is reduced by 18%.

[0180] As a further solution of this embodiment, the multi-substrate adaptability treatment includes:

[0181] For porous substrates, increase the distance between the nozzle and the workpiece by 0.3 - 0.8 mm and increase the material flow rate by 10% - 20%.

[0182] For wood and plastic substrates, dynamically match the material viscosity threshold of 50 - 200 mPa·s and the UV band of 365 - 405 nm.

[0183] Real-time monitor the residual amount of paint on the surface of the fixture. When the residual amount > 0.1 g / cm 2 trigger a cleaning warning and reduce the spraying pressure at the adjacent station.

[0184] In this embodiment, it is achieved through the following steps:

[0185] 1. Substrate identification and parameter matching:

[0186] The vision system scans the fan blades (ABS plastic, surface energy 34 mN / m). After identifying the material:

[0187] Set the material viscosity threshold: 120 mPa·s (suitable for ABS);

[0188] Select the UV band: 395 nm (suitable for non-polar surfaces).

[0189] 2. Treatment of porous substrates:

[0190] If it is a wooden fan blade (porosity 18%):

[0191] Increase the nozzle spacing by 0.6 mm (default 1.2 mm → 1.8 mm);

[0192] Increase the material flow rate by 18% (50 mL / min → 59 mL / min).

[0193] 3. Enhancing the adhesion of non-polar substrates:

[0194] For PP plastic fan blades (surface energy 29 mN / m):

[0195] Reduce the semi-curing rate to 65% (default 75%);

[0196] Prolong the UV pre-curing time to 2.5 s (default 1.5 s).

[0197] After operating through the above steps, the test data is as follows:

[0198] Substrate type Adhesion (ASTM D3359) Coating porosity Adaptation time ABS plastic fan blade 5B 0％ 2 min Wooden fan blade 4B 8％ 3 min PP plastic fan blade 5B 2％ 2.5 min

[0199] In this embodiment, the adhesion can be improved: the passing rate of the cross-cut test of the ABS fan blade coating is increased from 85% to 100%, and the multi-substrate switching time is shortened by 60% (originally 8 min).

[0200] As a further solution of this embodiment, the dual-material interfacial bonding is achieved in the following manner:

[0201] The first layer of epoxy resin-based material contains unreacted glycidyl ether groups, and 3 wt% of glycidyl ether-modified epoxy resin (epoxy value 0.45) is added.

[0202] The second layer of polyurethane-based material contains isocyanate groups, and 2 wt% of isocyanate curing agent (NCO content 6.5%) is added.

[0203] During the secondary curing, the active groups in the semi-cured layer form covalent bonds with the second-layer material. During the secondary curing, the interface temperature rises to 80 °C (to promote the formation of covalent bonds).

[0204] In this step, compared with the traditional process, the interlaminar shear strength of this application can be increased from 6 MPa to 18 MPa. Under the environment of 85 °C / 85% RH for 500 h, the adhesion after high-temperature and high-humidity aging is improved from 1B to 4B.

[0205] As a further solution of this embodiment, the environmental parameter compensation includes:

[0206] Real-time collect data on environmental temperature, humidity and air flow velocity;

[0207] Adjust the proportion of conductive particles by 0.2% corresponding to the humidity change gradient ΔRH = 10%;

[0208] When the air flow velocity > 2 m / s, the spraying pressure is increased by 10% - 15%.

[0209] In this step:

[0210] Humidity response control:

[0211] When the workshop RH rises from 50% to 80%:

[0212] The doping ratio of carbon nanotubes is increased from 0.6% to 1.0%;

[0213] The moving speed of the nozzle head changes from 1.2 m / s → 1.1 m / s, a decrease of 8%.

[0214] Air flow interference compensation:

[0215] When the workshop wind speed > 1.5 m / s:

[0216] The spraying pressure changes from 0.25 MPa → 0.28 MPa, an increase of 12%;

[0217] UV intensity from 80 mW / cm 2 → 92 mW / cm 2 , an increase of 15%.

[0218] Through this step, compared with the surface resistance deviation < ±30% under the previous humidity fluctuation, the surface resistance deviation of this application under the humidity fluctuation is < ±10%, which can improve the resistance stability well. The thickness deviation under strong wind interference is reduced from ±15 μm to ±5 μm, and the coating uniformity is also improved.

[0219] As a further solution of this, the nozzle head maintenance control includes:

[0220] Execute the nozzle head cleaning step during the spraying interval, and use an air pressure of 0.5 - 0.8 MPa to remove the residual coating;

[0221] Automatically set the cleaning cycle according to the material viscosity, and the trigger condition is a viscosity value of 200 - 500 mPa·s.

[0222] Through this step, the nozzle can be automatically cleaned to prevent nozzle blockage from affecting the spraying effect.

[0223] As a further solution of this embodiment, the quality closed-loop control includes:

[0224] Use the laser triangulation method to detect the coating thickness in real time, with a sampling frequency ≥ 100 Hz for testing. The laser thickness gauge model is Keyence LJ-V7080, scanning the surface of the fan blade at a frequency of 500 Hz, and the data is transmitted to the MES system in real time to generate an SPC control chart.

[0225] When spraying anomalies are detected, automatically switch to the spare nozzle and generate a fault log.

[0226] The spraying data is uploaded to the MES system in real time to generate process optimization suggestions.

[0227] Through the above steps, the maintenance cost can be reduced, the troubleshooting cycle can be shortened, and the qualified rate of the fan blade dynamic balance is increased from 92% to 99.5%.

[0228] As a further solution of this embodiment, the workpiece includes household appliances or electronic devices or lightweight double-sided coated workpieces, where:

[0229] For household appliances, the radius of curvature of the workpiece curved surface is 200 - 800 mm, and a dust-proof coating is prepared.

[0230] Spraying of the antistatic film layer on the electronic device housing, and the resistance value of the antistatic film layer is 10 6 -10 9 Ω·m.

[0231] For lightweight double-sided coated workpieces such as fan blades, with a thickness ≤ 2 mm, double-sided spraying can be performed.

Claims

1. A method for controlling spraying based on adaptive semi-cured interface superposition, characterized in that The following steps are involved: S1. Generate spray path parameters, including: generate multiple spray stations according to the size of the workpiece, and generate spray path parameters according to the surface curvature of the workpiece and the spacing between adjacent stations, the ratio of the conveyor belt moving speed to the lateral moving speed of the nozzle is 1:1.5-1:1.2, and the spray pressure at the intersection of adjacent stations is reduced by 20%-40%; S2, obtain the workpiece offset data in real time through the visual positioning system, generate three-dimensional coordinate compensation data based on the image matching algorithm, and trigger the real-time re-planning of the spray path when the offset exceeds the preset threshold; S3, control multiple groups of nozzles to perform in alternating spraying mode: after spraying the first layer of material at the first station, use 50-100mW / cm 2 UV intensity irradiation for 0.5-2s, forming a semi-cured layer with a light curing rate of 70%-85% and a thickness of 5-20μm; S4. After the conveyor belt moves to the second station, the nozzle path is corrected so that the boundary between the two stations is 0.5-2mm, and the two stations are executed simultaneously: the second station sprays the first layer of material and partially solidifies it, and the first station sprays the second layer of material and uses 150-200mW / cm 2 UV intensity curing to light curing rate ≥ 95%; S5, cycle steps S3-S4 to complete multi-layer spraying, and the interlayer bonding strength is ≥15MPa; S6. Dynamically adjust the doping ratio of nano-conductive particles in the spraying material by 0.1%-1.5% according to the ambient humidity, so that the surface resistance value is controlled within 10 6 -10 9 Ω·m.

2. According to claim 1, a method for controlling spraying based on adaptive semi-curing interface superposition is characterized in that The spraying path planning includes: Surfaces with a surface drop of ≤2cm are considered flat for path planning; For surfaces with a curvature radius of >50mm, a piecewise linear approximation algorithm is used to generate the spraying trajectory; When the coating thickness deviation measured by the online thickness detection device exceeds ±5%, the nozzle flow and moving speed are adjusted within 0.5s, with a control accuracy of ±1.5μm.

3. According to claim 1, a method for controlling spraying based on adaptive semi-curing interface superposition is characterized in that The curing control includes: The first layer is partially cured using a 395nm wavelength UV light source to preferentially cure the surface layer; The secondary curing uses a 365nm wavelength UV light source to strengthen deep cross-linking; The viscosity of the semi-cured layer is controlled to 2000-5000 Pa·s by adjusting the ratio of the spraying speed and the UV irradiation intensity.

4. According to claim 1, a method for controlling spraying based on adaptive semi-curing interface superposition is characterized in that The anti-static regulation includes: When the ambient humidity RH>70%, the carbon nanotube doping ratio increases to 0.8%-1.2%; For substrates with a dielectric constant of ε≤3, the proportion of conductive particles is adjusted in real time to make the resistance deviation ≤±15%; For non-polar substrates, reduce the semi-cure rate to 60%-75% to enhance adhesion.

5. According to claim 1, a method for controlling spraying based on adaptive semi-curing interface superposition is characterized in that The multi-substrate adaptability treatment includes: For porous substrates, increase the distance between the nozzle and the workpiece by 0.3-0.8mm and increase the material flow rate by 10%-20%; For wood and plastic substrates, dynamically match the material viscosity threshold of 50-200mPa·s and UV band of 365-405nm; Real-time monitoring of the residual amount of coating on the fixture surface. When the residual amount is greater than 0.1g / cm 2 The cleaning warning is triggered and the spraying pressure of the adjacent workstations is reduced.

6. According to claim 1, a method for controlling spraying based on adaptive semi-curing interface superposition is characterized in that The dual material interface bonding is achieved by: The first layer of epoxy resin-based material contains unreacted glycidyl ether groups; The second layer of polyurethane-based material contains isocyanate groups; During secondary curing, the active groups in the semi-cured layer covalently bond with the second layer material.

7. According to claim 1, a method for controlling spraying based on adaptive semi-curing interface superposition is characterized in that Environmental parameter compensation includes: Real-time collection of ambient temperature, humidity and air flow velocity data; According to the humidity change gradient ΔRH = 10%, the proportion of conductive particles is adjusted by 0.2%; When the air flow velocity is greater than 2m / s, the spraying pressure increases by 10%-15%.

8. The method for controlling spraying based on adaptive semi-curing interface superposition according to claim 1, characterized in that The nozzle maintenance control includes: Perform the nozzle cleaning step in the interval between spraying, using 0.5-0.8MPa air pressure to remove residual paint; The cleaning cycle is automatically set according to the material viscosity, and the trigger condition is a viscosity value of 200-500mPa·s.

9. The method for controlling spraying based on adaptive semi-curing interface superposition according to claim 1, characterized in that The quality closed-loop control includes: Laser triangulation method is used to detect coating thickness in real time, with a sampling frequency of ≥100Hz; When a spraying abnormality is detected, it automatically switches to the backup nozzle and generates a fault log; Spraying data is uploaded to the MES system in real time to generate process optimization suggestions.

10. The method for controlling spraying based on adaptive semi-cured interface superposition according to claim 1, characterized in that The workpiece includes a housing of a household appliance or electronic equipment or a lightweight double-sided coated workpiece for synchronous processing.

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