Manufacturing method of aluminum alloy nickel-plated hand plate of HUD reflecting mirror

Abstract

The invention discloses a method for manufacturing an aluminum alloy nickel-plated hand plate of an HUD reflector, which comprises the following steps of: simulating the total deformation trend of a hand plate to be processed in a nickel plating process through simulation software, analyzing material characteristics by combining with a digital-analog drawing file, and selecting a raw material matched with an aluminum alloy base material, so that surface deformation caused by internal stress of the material or difference of thermal expansion coefficients is effectively avoided. In the processing link, a processing program based on simulation data is adopted to carry out layered multiple processing on the raw materials, the accumulation of processing thermal stress is reduced by controlling cutting parameters, and meanwhile, the formation of rainbow patterns is inhibited from the source by combining with nickel plating process optimization. And finally, superfinishing and manual polishing are carried out on the nickel-plated hand plate through three-coordinate detection and superfinishing amount calculation, so that the rainbow pattern phenomenon caused by uneven surface microstructure or local stress concentration is thoroughly eliminated, the optical performance of the HUD reflector hand plate is further improved, meanwhile, the rainbow pattern defect rate is reduced and eliminated, and the quality of the HUD reflector hand plate is improved. The technical problem that an existing aluminum alloy hand plate finished product is heavy in rainbow pattern is solved.

Description

Technical Field

[0001] This invention relates to the field of reflector technology, and specifically to a method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector. Background Technology

[0002] In recent years, the per capita car ownership has been increasing year by year, and at the same time, road safety accidents have also been on the rise. People are increasingly turning their attention to intelligent driving, using technology to ensure driving safety. Head-up display (HUD) systems are a type of intelligent driver assistance system that projects information such as instrument panel, tachometer, and fuel gauge onto the windshield, reducing blind spots caused by drivers looking down to check information. The projection position and the size of the projected image can be determined through optical design. Its optical performance is verified by manufacturing high-precision aluminum alloy optical components. However, current aluminum alloy prototypes have the following drawbacks: first, the finished product has a heavy rainbow pattern; second, there are visible machining marks. Therefore, surface modification of the optical surface of aluminum alloy prototypes is needed to solve the problems of heavy rainbow patterns and machining marks. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing a nickel-plated aluminum alloy prototype for HUD reflectors, so as to solve the technical problem of heavy rainbow patterns in existing finished aluminum alloy prototypes.

[0004] The technical solution of this invention is implemented as follows:

[0005] A method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector, comprising:

[0006] Step S1: Obtain the total deformation trend of the pre-nickel plating on the prototype to be processed based on engineering simulation software;

[0007] Step S2: Generate a digital model file based on the overall deformation trend, and select the raw materials for making the prototype to be processed;

[0008] Step S3: The raw materials are processed into the prototype to be processed through a processing program, and nickel plating is performed on the prototype to be processed.

[0009] Step S4: Detect the surface shape and external dimensions of the nickel-plated prototype, calculate the ultra-precision machining amount, and perform ultra-precision machining and hand polishing to produce a nickel-plated aluminum alloy prototype for the HUD reflector without rainbow patterns.

[0010] A further technical solution is that step S1 specifically includes:

[0011] Step S11: Construct a three-dimensional geometric model of the prototype to be processed using engineering simulation software, and define the boundary conditions in the pre-nickel plating process;

[0012] Step S12: Input the physical properties of the prototype to be processed and the boundary conditions of the pre-plated nickel into the engineering simulation software as input conditions for the analysis of the engineering simulation software;

[0013] Step S13: Based on the three-dimensional geometric model of the prototype to be processed and the boundary conditions of the pre-plated nickel, run simulation calculations to obtain the displacement field, strain field and total deformation trend data of each node of the prototype to be processed during the pre-plating nickel process.

[0014] Step S14: Compare the total deformation trend with the experimental measurement data or theoretical calculation value. If the deviation exceeds the preset threshold, adjust the three-dimensional geometric model parameters of the hand-made prototype or the boundary conditions of the pre-plated nickel and re-simulate until the result meets the expected accuracy.

[0015] A further technical solution is that step S14 specifically includes:

[0016] Step S141: Compare the total deformation trend data of the pre-plated nickel of the hand plate to be processed with the experimental measurement data or theoretical calculation value, and calculate the deviation between the two.

[0017] Step S142: If the deviation exceeds a preset threshold, adjust at least one of the following three-dimensional geometric model parameters of the prototype to be processed or the boundary condition parameters in the pre-nickel plating process according to the deviation characteristics.

[0018] Step S143: Re-execute the simulation calculation based on the adjusted parameters, repeating the process of steps S141 and S142 until the deviation of the total deformation trend stabilizes within the preset threshold range and the expected accuracy of the simulation results is achieved.

[0019] A further technical solution is that step S2 specifically includes:

[0020] Step S21: Use the total deformation trend data of the pre-plated nickel as the input condition of the prototype model to be processed, and define the boundary constraints and load distribution of the prototype model to be processed;

[0021] Step S22: Calculate based on the total deformation trend data of the pre-plated nickel and the boundary constraints and load distribution to generate the digital model file that meets the requirements of the pre-plated nickel process;

[0022] Step S23: Based on the structural features of the prototype model to be processed in the digital model file and the requirements of the pre-plating nickel process, formulate raw material selection criteria;

[0023] Step S24: Select the raw materials for the prototype to be processed from the material library that meets the selection criteria, based on the selection criteria.

[0024] A further technical solution is that step S3 specifically includes:

[0025] Step S31: Process the selected raw materials into the preliminary shape of the hand prototype to be processed, and control the processing accuracy and surface roughness;

[0026] Step S32: Before the nickel plating operation, pre-treat the mold after the prototype is processed;

[0027] Step S33: Immerse the mold in a chemical nickel plating solution to uniformly deposit it on the surface of the hand plate, forming a plating layer with a thickness of 45-60μm, and adjust the pH value and temperature of the plating solution.

[0028] Step S34: Clean and dry the nickel-plated mold, and perform performance testing.

[0029] A further technical solution is that step S32 specifically includes:

[0030] Step S321: Dust removal treatment is performed on the surface of the processed mold by blowing away surface particles with compressed air and removing surface oil stains with an alkaline degreasing agent;

[0031] Step S322: Immerse the degreased mold in a dilute hydrochloric acid solution and control the pickling time to 15-30 seconds to remove the surface oxide layer and rust.

[0032] Step S323: Rinse the acid-activated mold with deionized water in three stages, then immerse it in a neutralizing solution to neutralize residual acidic substances, and verify the thoroughness of cleaning by conductivity testing;

[0033] Step S324: Passivate the surface of the mold with chromate passivation solution to form a dense oxide film;

[0034] Step S325: Place the passivated mold in a hot air circulating drying oven, and then inspect it visually and observe it under a microscope.

[0035] A further technical solution is that step S33 specifically includes:

[0036] Step S331: Fix the mold as the cathode and immerse it in the electroless nickel plating solution. The anode is a pure nickel plate, and the electrode spacing is set to 5-10 cm.

[0037] Step S332: Use an electrochemical workstation to collect the potential-time curve and current-time curve of the plating solution in real time, and record the sampling frequency at 1Hz;

[0038] Step S333: After nickel plating is completed, the resistivity of the plating layer is measured using the DC four-probe method.

[0039] A further technical solution is that step S34 specifically includes:

[0040] Step S341: Immerse the nickel-plated mold in room temperature deionized water and apply ultrasonic waves. After cleaning, confirm the conductivity of the residual water on the surface by conductivity detection.

[0041] Step S342: Place the cleaned mold in an environment of 50-60℃ and accelerate the evaporation of surface moisture by airflow;

[0042] Step S343: Measure the coating thickness and coating adhesion of the mold;

[0043] Step S344: Immerse the mold in an acidic solution to collect data, generate an impedance-frequency curve, and measure the hardness of the coating.

[0044] A further technical solution is that step S344 specifically includes:

[0045] Step S3441: Immerse the mold in hydrochloric acid solution, apply an amplitude AC signal, collect electrochemical impedance data in the frequency range of 0.01-100 kHz, and generate the impedance-frequency curve;

[0046] Step S3442: Using the microhardness test method, apply a load to the surface of the part to be plated, measure the diagonal length of the indentation, and calculate the Vickers hardness value.

[0047] A further technical solution is that step S4 specifically includes:

[0048] Step S41: Determine the reference surface of the nickel-plated prototype using a non-contact thickness measurement method, and evenly distribute measurement points along the reference surface, record the three-dimensional coordinates, and calculate the surface profile deviation.

[0049] Step S42: Calculate the ultra-precision machining allowance based on the designed surface shape and actual measurement data, and set the tool diameter, feed rate, speed and step distance for ultra-precision machining;

[0050] Step S43: Hand-polish the surface of the prototype. After polishing, check the surface roughness and eliminate rainbow patterns. If rainbow patterns are present, continue hand-polishing.

[0051] Step S44: Verify the surface shape error and edge contour tolerance of the finished product.

[0052] The beneficial effects of this invention are as follows:

[0053] By pre-simulating the overall deformation trend of the prototype during nickel plating using engineering simulation software and analyzing material properties using digital model files, raw materials matching the aluminum alloy substrate are precisely selected, effectively avoiding surface deformation caused by differences in material internal stress or thermal expansion coefficients. In the processing stage, a simulation-based machining program performs layered, multi-stage processing of the raw materials. By controlling cutting parameters, the accumulation of processing thermal stress is reduced. Simultaneously, combined with nickel plating process optimization, the formation of rainbow patterns is suppressed at its source. Finally, through coordinate measuring machine (CMM) inspection and ultra-precision machining calculation, the nickel-plated prototype undergoes ultra-precision machining and hand polishing to completely eliminate rainbow patterns caused by uneven surface microstructure or localized stress concentration. This improves the optical performance of the HUD reflector prototype while reducing or eliminating the rainbow pattern defect rate, solving the technical problem of heavy rainbow patterns in existing aluminum alloy prototype finished products. Attached Figure Description

[0054] Figure 1 The present invention provides a step-by-step diagram of a method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector;

[0055] Figure 2 The following is a detailed flowchart of step S1 of the method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector provided by the present invention.

[0056] Figure 3 The following is a detailed flowchart of step S2 of the method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector provided by the present invention.

[0057] Figure 4 The following is a detailed flowchart of step S3 of the method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector provided by the present invention.

[0058] Figure 5 The following is a detailed flowchart of step S4 of the method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector provided by the present invention. Detailed Implementation

[0059] To better understand the technical content of this invention, specific embodiments are provided below, and the invention will be further described in conjunction with the accompanying drawings.

[0060] See Figures 1 to 5 This invention provides a method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector, comprising:

[0061] Step S1: Obtain the total deformation trend of the pre-nickel plating on the prototype to be processed based on engineering simulation software;

[0062] Step S2: Generate a digital model file based on the overall deformation trend, and select the raw materials for making the prototype to be processed;

[0063] Step S3: The raw materials are processed into a prototype to be processed through the processing program, and nickel plating is performed on the prototype to be processed.

[0064] Step S4: Detect the surface shape and external dimensions of the nickel-plated prototype, calculate the ultra-precision machining amount, and perform ultra-precision machining and hand polishing to produce a nickel-plated aluminum alloy prototype of the HUD reflector without rainbow pattern.

[0065] It should be noted that the engineering simulation software can be ANSYS. HUD refers to a vehicle-mounted head-up display system. The prototype to be processed can be a pre-designed model in the engineering simulation software, and the nickel plating process of the prototype is simulated within the software to achieve data simulation.

[0066] This invention uses software simulation analysis to reduce project risks and verify project feasibility in advance. By allowing for machining allowances, stress deformation of the product after processing can be effectively controlled. Product structural design, including the addition of reinforcing ribs and process tables, can enhance product structural strength and secondary finishing, reduce stress deformation, and improve product surface accuracy.

[0067] In this embodiment of the invention, engineering simulation software is used to pre-simulate the overall deformation trend of the prototype during nickel plating. Combined with analysis of material properties using digital model files, raw materials matching the aluminum alloy substrate are precisely selected, effectively avoiding surface deformation caused by differences in material internal stress or thermal expansion coefficients. During the processing stage, a processing program based on simulation data is used to process the raw materials in layers multiple times. By controlling cutting parameters, the accumulation of processing thermal stress is reduced. Simultaneously, combined with optimization of the nickel plating process, the formation of rainbow patterns is suppressed from the source. Finally, through coordinate measuring machine (CMM) inspection and ultra-precision machining calculation, the nickel-plated prototype undergoes ultra-precision machining and hand polishing to completely eliminate the rainbow pattern phenomenon caused by uneven surface microstructure or localized stress concentration. This improves the optical performance of the HUD reflector prototype while reducing or eliminating the rainbow pattern defect rate, solving the technical problem of heavy rainbow patterns in existing aluminum alloy prototype finished products.

[0068] Preferably, step S1 specifically includes:

[0069] Step S11: Construct a three-dimensional geometric model of the prototype to be processed using engineering simulation software, and define the boundary conditions in the pre-nickel plating process;

[0070] Step S12: Input the physical properties of the prototype to be processed and the boundary conditions for pre-plating nickel into the engineering simulation software as input conditions for analysis by the engineering simulation software.

[0071] Step S13: Based on the three-dimensional geometric model of the prototype to be processed and the boundary conditions of the pre-plated nickel, run simulation calculations to obtain the displacement field, strain field and total deformation trend data of each node of the prototype to be processed during the pre-plating nickel process.

[0072] Step S14: Compare the overall deformation trend with the experimental measurement data or theoretical calculation value. If the deviation exceeds the preset threshold, adjust the three-dimensional geometric model parameters of the prototype to be processed or the boundary conditions of the pre-plated nickel and re-simulate until the result meets the expected accuracy.

[0073] It should be noted that the preset threshold can be 5%. The parameters of the three-dimensional geometric model can be thickness distribution and structural symmetry. The boundary conditions for pre-plating nickel can be temperature gradient and plating solution flow rate.

[0074] In this embodiment of the invention, a three-dimensional geometric model is constructed in engineering simulation software based on the actual geometric structure of the prototype to be processed. Boundary conditions, including the temperature field, pressure field, and flow characteristics of the plating solution in the pre-plating process, are defined to simulate the actual nickel plating environment. Subsequently, the elastic modulus and thermal expansion coefficient of the prototype material, along with the boundary conditions of the pre-plating process, are imported into the simulation software as input parameters. Finite element analysis is used to calculate the displacement field, strain field, and overall deformation trend data of each node on the prototype during the nickel plating process. Finally, the simulation results are compared with experimental measurement data or theoretical calculations. If the deviation exceeds a preset threshold, the parameters of the three-dimensional geometric model are adjusted or the boundary conditions of the pre-plating process are modified. The simulation calculation is repeated until the overall deformation trend data meets the expected accuracy requirements, providing data support for subsequent processing parameter optimization.

[0075] Furthermore, step S14 specifically includes:

[0076] Step S141: Compare the total deformation trend data of the pre-plated nickel of the hand-made prototype with the experimental measurement data or theoretical calculation value, and calculate the deviation between the two.

[0077] Step S142: If the deviation exceeds the preset threshold, adjust at least one of the following three-dimensional geometric model parameters of the prototype to be processed or the boundary condition parameters in the pre-plating nickel process according to the deviation characteristics.

[0078] Step S143: Re-execute the simulation calculation based on the adjusted parameters, repeating the process of steps S141 and S142 until the deviation of the total deformation trend stabilizes within the preset threshold range and the expected accuracy of the simulation results is achieved.

[0079] It should be noted that the formula for calculating the deviation can be the root mean square error. The deviation characteristics can be localized stress concentration or global deformation direction shift.

[0080] In this embodiment of the invention, the total deformation trend data of the pre-nickel plating process of the prototype generated by engineering simulation software is compared with experimental measurement data or theoretical calculation values, and the difference between the two is quantified by a deviation calculation formula. If the calculated deviation exceeds a preset threshold of 5%, the parameters of the three-dimensional geometric model or the boundary condition parameters in the pre-nickel plating process are adjusted according to the deviation characteristics. After adjustment, the simulation calculation is re-executed and the deviation is compared again. Iterative optimization is carried out until the deviation of the total deformation trend stabilizes within the preset threshold range, and the expected accuracy of the simulation results is achieved, with surface shape error ≤ 0.01 mm and strain field uniformity ≥ 95%, thus realizing accurate prediction of the deformation behavior of the nickel plating process.

[0081] Preferably, step S2 specifically includes:

[0082] Step S21: Use the total deformation trend data of pre-plated nickel as the input condition for the prototype model to be processed, and define the boundary constraints and load distribution of the prototype model to be processed;

[0083] Step S22: Calculate based on the total deformation trend data of pre-plated nickel, boundary constraints, and load distribution to generate a digital model file that meets the requirements of the pre-plated nickel process;

[0084] Step S23: Based on the structural features of the prototype model to be processed and the requirements of the pre-plating nickel process in the digital model file, formulate the raw material selection criteria;

[0085] Step S24: Select the raw materials for the prototype to be processed from the material library that meets the selection criteria, based on the selection criteria.

[0086] It should be noted that boundary constraints include fixed ends and free ends, and load distribution includes plating solution pressure and temperature gradient.

[0087] In this embodiment of the invention, the total deformation trend data of pre-nickel plating obtained from engineering simulation is used as the input condition for the prototype model to be processed. The boundary constraints and load distribution of the model are defined in conjunction with actual process requirements. Based on the deformation trend data and boundary conditions, a digital model file that meets the requirements of the pre-nickel plating process is generated through finite element analysis, ensuring that the thickness distribution, surface transition radius structural parameters of the prototype model to be processed match the stress-strain behavior during the nickel plating process. Next, based on the high-stress region distribution, geometric complexity structural characteristics, and the process requirements for coating uniformity and surface roughness during pre-nickel plating, raw material selection criteria are formulated, including material type, physical properties, processing performance, and cost range. Finally, raw materials meeting the requirements are selected from the material library according to the above criteria, prioritizing aluminum alloys with stable market supply, high recyclability, and a strength-cost balance, ensuring compatibility with subsequent processing and nickel plating processes, and achieving precise matching between prototype design and process requirements. The material type can be an aluminum alloy grade; the physical properties can be an elastic modulus ≥70 GPa and a coefficient of thermal expansion ≤23×10⁻⁻⁻⁻⁶. 6 / K; Machining performance can be a cutting rate ≥80%; Cost range can be a unit cost ≤200 yuan / kg.

[0088] Preferably, step S3 specifically includes:

[0089] Step S31: Process the selected raw materials into the preliminary shape of the prototype to be processed, and control the processing accuracy and surface roughness;

[0090] Step S32: Before the nickel plating operation, pre-treat the mold after the prototype is processed;

[0091] Step S33: Immerse the mold in the electroless nickel plating solution, deposit it evenly on the surface of the hand plate to form a coating with a thickness of 45-60μm, and ensure the quality of the coating by adjusting the pH value and temperature of the plating solution.

[0092] Step S34: Clean and dry the nickel-plated mold, and perform performance testing.

[0093] In this embodiment of the invention, the selected aluminum alloy raw material is CNC machined into a preliminary shape for the prototype. A climb milling method is used, the tool extension length is shortened to 5-8 times the tool diameter, and the finishing allowance is controlled to ≤0.1 mm to maintain a surface roughness below Ra0.8 μm, ensuring the uniformity of the subsequent nickel plating layer. The machined prototype undergoes pretreatment, including chemical degreasing, acid etching (a mixture of hydrochloric acid and nitric acid), ultrasonic cleaning, and two zinc immersions to remove the oxide film and enhance the adhesion between the substrate and the plating layer. The pretreated prototype is then immersed in a chemical nickel plating solution and reacted for 120 min at a pH of 4.8±0.2 and a temperature of 85℃±2℃. The uniformity and density of the nickel-phosphorus alloy plating layer are controlled by adjusting the pH of the plating solution (below 4.6 easily generates bubbles, above 5.0 decreases the deposition rate) and the temperature (below 80℃ the deposition rate is too slow, above 95℃ the plating solution decomposes). Finally, an amorphous plating layer with a thickness of 45-60 μm is formed. The nickel-plated prototype undergoes a three-stage water washing (deionized water) and hot air drying (80℃, 10 min). The corrosion resistance, hardness, and bonding strength of the plating are verified by salt spray test, microhardness test ≥500, and adhesion scratch test with a bonding strength ≥10MPa. This ensures the uniformity, adhesion, and functionality of the nickel-plated layer on the aluminum alloy prototype, meeting the high surface quality requirements of precision optical components such as HUD mirrors.

[0094] Furthermore, step S32 specifically includes:

[0095] Step S321: Dust removal treatment is performed on the surface of the processed mold. Compressed air is used to blow away surface particles, and an alkaline degreasing agent is used to remove surface oil stains.

[0096] Step S322: Immerse the degreased mold in a dilute hydrochloric acid solution and control the pickling time to 15-30 seconds to remove the surface oxide layer and rust.

[0097] Step S323: Rinse the acid-activated mold three times with deionized water, then immerse it in a neutralizing solution to neutralize residual acidic substances, and verify the thoroughness of cleaning by conductivity testing;

[0098] Step S324: Passivate the mold surface with chromate passivation solution to form a dense oxide film;

[0099] Step S325: Place the passivated mold in a hot air circulating drying oven, and then inspect it visually and observe it under a microscope.

[0100] In this embodiment of the invention, the surface of the processed prototype mold is subjected to dust removal treatment. Compressed air is used to blow away surface metal debris and dust, followed by soaking or spraying with an alkaline degreasing agent for 10-15 minutes to remove surface oil and residual lubricant from the processing. The degreased mold is then immersed in a dilute hydrochloric acid solution (5-10% HCl solution by mass fraction), and the pickling time is controlled at 15-30 seconds to dissolve the surface alumina layer and rust, exposing the active metal substrate. A three-stage deionized water rinse (initial rinse → intermediate rinse → final rinse) is used, with each rinsing time being 30-60 seconds to ensure the removal of residual acid and metal ions. The mold is then immersed in a neutralizing solution for 1-2 minutes to neutralize residual acidic substances, and the thoroughness of cleaning is verified by conductivity testing. Subsequently, the mold is immersed in a chromate passivation solution for 2-5 minutes to form a dense chromate oxide film with a thickness of 0.1-0.5 μm at room temperature, enhancing the corrosion resistance of the substrate. Finally, the passivated mold is placed in a hot air circulating drying oven (temperature 80-100℃, time 10-15 minutes) for drying. Then, the surface treatment quality is confirmed by visual inspection to ensure that there are no spots or rust marks, and by microscopic observation (magnification 10×-50×). This ensures the cleanliness, activity, and uniformity of the oxide film on the mold surface, providing a stable substrate for the subsequent nickel plating process. This solves the technical problems of poor coating adhesion and insufficient uniformity caused by surface contamination or incomplete removal of the oxide layer in traditional treatments.

[0101] Furthermore, step S33 specifically includes:

[0102] Step S331: Fix the mold as the cathode and immerse it in the electroless nickel plating solution. Use a pure nickel plate as the anode and set the electrode spacing to 5-10 cm.

[0103] Step S332: Use an electrochemical workstation to collect the potential-time curve and current-time curve of the plating solution in real time, and record the sampling frequency at 1Hz;

[0104] Step S333: After nickel plating is completed, the resistivity of the plating layer is measured using the DC four-probe method.

[0105] In this invention, the mold to be plated is fixed as the cathode and immersed in a chemical nickel plating solution. A pure nickel plate is used as the anode, and the electrode spacing is set to 5-10 cm. This spacing range ensures uniform current density distribution, avoiding situations where the local current density is too high due to electrodes being too close, causing the plating layer to burn or become too thick, or that the current efficiency is reduced due to electrodes being too far apart. Nickel ions in the plating solution undergo a reduction reaction on the cathode surface, while hypophosphite is oxidized to generate phosphorus and hydrogen gas is released, forming an amorphous Ni-P alloy plating layer.

[0106] Subsequently, the potential-time and current-time curves of the plating solution were acquired in real time using an electrochemical workstation, with a sampling frequency set to 1 Hz. The potential curve reflects the potential shift of the hydrogen evolution side reaction, while the current curve characterizes the peak current corresponding to the nucleation stage of plating crystallization, and the steady-state current corresponding to the uniform growth stage. By monitoring the potential fluctuation range in the Et curve (within ±50 mV for stable deposition), it can be determined whether the pH value (theoretically optimal 4.8±0.2) and temperature (85±2℃) of the plating solution deviate from the process window; a peak-to-steady-state ratio of the current-time curve >0.6 reflects the integrity and density of the plating crystallization.

[0107] After nickel plating, the resistivity of the plating layer is measured using a DC four-probe method. Four probes are arranged in a square (spaced d = 1 mm) and contact the plating surface. A constant current I (10 mA) is applied, and the voltage drop V between adjacent probes is measured. The resistivity is calculated using the formula ρ = V·π·d / I. By using four probes for separate current injection and voltage measurement, contact resistance interference is eliminated, making this method suitable for amorphous Ni-P alloy plating layers. If the measured resistivity exceeds the design target range of 100 ± 15 μΩ·cm, it indicates that the plating solution parameters or electrode spacing need adjustment.

[0108] Furthermore, step S34 specifically includes:

[0109] Step S341: Immerse the nickel-plated mold in room temperature deionized water and apply ultrasonic waves. After cleaning, confirm the conductivity of the residual water on the surface by conductivity testing.

[0110] Step S342: Place the cleaned mold in an environment of 50-60℃ and accelerate the evaporation of surface moisture through airflow;

[0111] Step S343: Measure the coating thickness and coating adhesion of the mold;

[0112] Step S344: Immerse the mold in an acidic solution to collect data, generate an impedance-frequency curve, and measure the hardness of the coating.

[0113] In this invention, the nickel-plated mold is immersed in room-temperature deionized water and ultrasonically cleaned (frequency 20-40 kHz) to remove residual unreacted hypophosphite and metal ions from the surface. The microbubbles generated by the ultrasonic cavitation effect burst, forming local high pressure >100 MPa and microjets that impact the mold surface, stripping away adsorbed particles and ionic contaminants. After cleaning, conductivity testing confirms that the residual water conductivity is ≤5 μS / cm, ensuring thorough deionized water rinsing. The cleaned mold is then placed in an environment of 50-60℃, where airflow accelerates surface moisture evaporation, enhancing the kinetic energy of water molecules. The airflow carries away water vapor from the liquid surface, reducing local humidity and shortening drying time. Next, X-ray fluorescence spectrometry is used to measure the coating thickness, and the cross-section is observed using a metallographic microscope to calculate the average thickness. Simultaneously, the adhesion is tested using a cross-cut test, and the target value for the coating peel-off area is ≤5% after peeling with tape, ensuring the bonding strength between the coating and the substrate. The mold was immersed in an acidic solution, and impedance-frequency curves (frequency range 10 mHz-100 kHz) were acquired using an electrochemical workstation to analyze the polarization resistance and charge transfer impedance of the coating under acidic conditions, thereby evaluating its corrosion resistance. Simultaneously, a microhardness tester was used to measure the coating hardness to a target value ≥400 HV, and the Vickers hardness was calculated based on the relationship between indentation depth and load.

[0114] Specifically, step S344 includes:

[0115] Step S3441: Immerse the mold in hydrochloric acid solution, apply an amplitude AC signal, collect electrochemical impedance data in the frequency range of 0.01-100 kHz, and generate an impedance-frequency curve;

[0116] Step S3442: Using the microhardness test method, apply a load to the surface of the part to be plated, measure the diagonal length of the indentation, and calculate the Vickers hardness value.

[0117] In this embodiment of the invention, the mold is immersed in hydrochloric acid solution, and a sinusoidal AC signal with an amplitude ≤10 mV (frequency range 0.01-100 kHz) is applied to the coating / electrolyte interface through an electrochemical workstation. The impedance ratio of the response current to voltage and its phase angle are measured. The real part of the impedance in the high-frequency region reflects the bulk resistance of the coating and the resistance of the solution, while the imaginary part of the impedance in the low-frequency region characterizes the charge transfer resistance and the double-layer capacitance. The corrosion resistance mechanism of the coating is analyzed using Nyquist plots and Bode plots. For example, the diameter of the high-frequency semicircle corresponds to the charge transfer resistance, and the slope in the low-frequency region reflects the diffusion resistance. If the charge transfer resistance decreases, it indicates that there are micropores or cracks in the coating, leading to accelerated penetration of the corrosive medium. A microhardness tester is used, and a test force (10 g-100 g) is applied to the coating surface with a diamond pyramid indenter (136° included angle), held for 15 s, and then unloaded. The diagonal length of the indentation is measured. The Vickers hardness value is calculated using the formula HV=F / (1.8544·d²). If the measured hardness value is lower than the alloy design value of ≥400 HV, it indicates that the phosphorus content in the plating solution or the heat treatment process needs to be adjusted.

[0118] Preferably, step S4 specifically includes:

[0119] Step S41: Determine the reference surface of the nickel-plated prototype using a non-contact thickness measurement method, and evenly distribute measurement points along the reference surface, record the three-dimensional coordinates, and calculate the surface profile deviation.

[0120] Step S42: Calculate the ultra-precision machining allowance based on the designed surface shape and actual measurement data, and set the tool diameter, feed rate, speed and step distance for ultra-precision machining;

[0121] Step S43: Hand-polish the surface of the prototype. After polishing, check the surface roughness and eliminate rainbow patterns. If rainbow patterns are present, continue hand-polishing.

[0122] Step S44: Verify the surface shape error and edge contour tolerance of the finished product.

[0123] It should be noted that non-contact thickness measurement methods can be white light interferometers or laser triangulation sensors.

[0124] In this embodiment of the invention, a non-contact thickness measurement method is employed, with points evenly distributed along the reference surface at intervals of 0.1-0.5 mm. Actual surface contour data is recorded using a three-dimensional coordinate acquisition system. The measured data is compared with the CAD-designed surface shape to calculate the deviation, generating a surface contour deviation cloud map to ensure the accuracy of the reference surface definition. Based on the deviation data between the designed surface shape and the actual contour, the ultra-precision machining allowance for each region is calculated using the least squares method and mapped to the machining parameter setting module. Ultra-precision machining is performed by setting the tool diameter, feed rate, speed, and step distance. If rainbow patterns are detected, hand polishing continues. A coordinate measuring machine is used to check the target value of the finished surface shape error (≤3μm) and the target value of the edge contour tolerance (≤0.02 mm). A microhardness tester is used to measure the target value of the coating surface hardness (≥400 HV).

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector, characterized in that, include: Step S1: Obtain the total deformation trend of the pre-nickel plating on the prototype to be processed based on engineering simulation software; Step S2: Generate a digital model file based on the overall deformation trend, and select the raw materials for making the prototype to be processed; Step S3: The raw materials are processed into the prototype to be processed through a processing program, and nickel plating is performed on the prototype to be processed. Step S4: Detect the surface shape and external dimensions of the nickel-plated prototype, calculate the ultra-precision machining amount, and perform ultra-precision machining and hand polishing to produce a nickel-plated aluminum alloy prototype for the HUD reflector without rainbow patterns.

2. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 1, characterized in that, Step S1 specifically includes: Step S11: Construct a three-dimensional geometric model of the prototype to be processed using engineering simulation software, and define the boundary conditions in the pre-nickel plating process; Step S12: Input the physical properties of the prototype to be processed and the boundary conditions of the pre-plated nickel into the engineering simulation software as input conditions for the analysis of the engineering simulation software; Step S13: Based on the three-dimensional geometric model of the prototype to be processed and the boundary conditions of the pre-plated nickel, run simulation calculations to obtain the displacement field, strain field and total deformation trend data of each node of the prototype to be processed during the pre-plating nickel process. Step S14: Compare the total deformation trend with the experimental measurement data or theoretical calculation value. If the deviation exceeds the preset threshold, adjust the three-dimensional geometric model parameters of the hand-made prototype or the boundary conditions of the pre-plated nickel and re-simulate until the result meets the expected accuracy.

3. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 2, characterized in that, Step S14 specifically includes: Step S141: Compare the total deformation trend data of the pre-plated nickel of the hand plate to be processed with the experimental measurement data or theoretical calculation value, and calculate the deviation between the two. Step S142: If the deviation exceeds a preset threshold, adjust at least one of the following three-dimensional geometric model parameters of the prototype to be processed or the boundary condition parameters in the pre-nickel plating process according to the deviation characteristics. Step S143: Re-execute the simulation calculation based on the adjusted parameters, repeating the process of steps S141 and S142 until the deviation of the total deformation trend stabilizes within the preset threshold range and the expected accuracy of the simulation results is achieved.

4. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 1, characterized in that, Step S2 specifically includes: Step S21: Use the total deformation trend data of the pre-plated nickel as the input condition of the prototype model to be processed, and define the boundary constraints and load distribution of the prototype model to be processed; Step S22: Calculate based on the total deformation trend data of the pre-plated nickel and the boundary constraints and load distribution to generate the digital model file that meets the requirements of the pre-plated nickel process; Step S23: Based on the structural features of the prototype model to be processed in the digital model file and the requirements of the pre-plating nickel process, formulate raw material selection criteria; Step S24: Select the raw materials for the prototype to be processed from the material library that meets the selection criteria, based on the selection criteria.

5. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 1, characterized in that, Step S3 specifically includes: Step S31: Process the selected raw materials into the preliminary shape of the hand prototype to be processed, and control the processing accuracy and surface roughness; Step S32: Before the nickel plating operation, pre-treat the mold after the prototype is processed; Step S33: Immerse the mold in a chemical nickel plating solution to uniformly deposit it on the surface of the hand plate, forming a plating layer with a thickness of 45-60μm, and adjust the pH value and temperature of the plating solution. Step S34: Clean and dry the nickel-plated mold, and perform performance testing.

6. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 5, characterized in that, Step S32 specifically includes: Step S321: Dust removal treatment is performed on the surface of the processed mold by blowing away surface particles with compressed air and removing surface oil stains with an alkaline degreasing agent; Step S322: Immerse the degreased mold in a dilute hydrochloric acid solution and control the pickling time to 15-30 seconds to remove the surface oxide layer and rust. Step S323: Rinse the acid-activated mold with deionized water in three stages, then immerse it in a neutralizing solution to neutralize residual acidic substances, and verify the thoroughness of cleaning by conductivity testing; Step S324: Passivate the surface of the mold with chromate passivation solution to form a dense oxide film; Step S325: Place the passivated mold in a hot air circulating drying oven, and then inspect it visually and observe it under a microscope.

7. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 5, characterized in that, Step S33 specifically includes: Step S331: Fix the mold as the cathode and immerse it in the electroless nickel plating solution. The anode is a pure nickel plate, and the electrode spacing is set to 5-10 cm. Step S332: Use an electrochemical workstation to collect the potential-time curve and current-time curve of the plating solution in real time, and record the sampling frequency at 1Hz; Step S333: After nickel plating is completed, the resistivity of the plating layer is measured using the DC four-probe method.

8. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 5, characterized in that, Step S34 specifically includes: Step S341: Immerse the nickel-plated mold in room temperature deionized water and apply ultrasonic waves. After cleaning, confirm the conductivity of the residual water on the surface by conductivity detection. Step S342: Place the cleaned mold in an environment of 50-60℃ and accelerate the evaporation of surface moisture by airflow; Step S343: Measure the coating thickness and coating adhesion of the mold; Step S344: Immerse the mold in an acidic solution to collect data, generate an impedance-frequency curve, and measure the hardness of the coating.

9. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 8, characterized in that, Step S344 specifically includes: Step S3441: Immerse the mold in hydrochloric acid solution, apply an amplitude AC signal, collect electrochemical impedance data in the frequency range of 0.01-100 kHz, and generate the impedance-frequency curve; Step S3442: Using the microhardness test method, apply a load to the surface of the part to be plated, measure the diagonal length of the indentation, and calculate the Vickers hardness value.

10. The method for manufacturing a nickel-plated aluminum alloy prototype for a HUD reflector according to claim 9, characterized in that, Step S4 specifically includes: Step S41: Determine the reference surface of the nickel-plated prototype using a non-contact thickness measurement method, and evenly distribute measurement points along the reference surface, record the three-dimensional coordinates, and calculate the surface profile deviation. Step S42: Calculate the ultra-precision machining allowance based on the designed surface shape and actual measurement data, and set the tool diameter, feed rate, speed and step distance for ultra-precision machining; Step S43: Hand-polish the surface of the prototype. After polishing, check the surface roughness and eliminate rainbow patterns. If rainbow patterns are present, continue hand-polishing. Step S44: Verify the surface shape error and edge contour tolerance of the finished product.

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