Thermal spraying intelligent control system and manufacturing method

Abstract

The invention belongs to the technical field of automatic control systems, and particularly relates to a thermal spraying intelligent control system and a manufacturing method.The system comprises a central controller, a multi-parameter sensing module, a motion executing mechanism and a technological parameter database; the central controller is configured to integrate sensing data and a physical model, and multi-parameter joint debugging of gas flow, spray gun movement and suspension liquid supply is achieved. The multi-parameter sensing module is configured to collect flame temperature, suspension flow, atomization air pressure and matrix surface temperature in real time; the motion executing mechanism is configured to control the six-degree-of-freedom motion of the spray gun and the rotation of the base body; the process parameter database is configured to store nozzle structure parameters, suspension liquid physical properties and coating thickness target values; according to the invention, global scheduling of multiple subsystems is realized through the central controller, and the subsystem islanding of the system is controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control systems, and particularly relates to a thermal spraying intelligent control system and a manufacturing method thereof. Background Art

[0002] Thermal spraying technology also plays an important role in the national economy. It can reduce energy consumption, reduce the use of raw materials, lower the performance requirements for the overall material, and can realize the repair and reuse of worn-out parts. Nano-coatings are a very important research direction in the international surface engineering field in recent years. Due to their properties such as increased strength, reduced micro-cracks, better thermal shock resistance, and low wear, a large amount of research work has been carried out on thermal spraying technology for the preparation of nano-coatings. In recent years, a new spraying technology for preparing nano-coatings - liquid-phase thermal spraying - has emerged. It is a very efficient nano-coating preparation technology. Among them, the suspension thermal spraying (HVSFS) technology has been widely used in various industries due to its high density and low porosity.

[0003] However, the existing control system of the HVSFS technology still has certain defects. The processes of subsystems such as temperature control, motion trajectory, and suspension supply operate independently, lacking a coordination mechanism, and the real-time feedback of the three-dimensional shape of the substrate is not integrated, resulting in a decrease in the bonding strength in the surface mutation area and ultimately unstable coating quality. Therefore, it is necessary to propose a new solution to meet the higher requirements of production and manufacturing. Summary of the Invention

[0004] The purpose of the present invention is to provide a thermal spraying intelligent control system and a manufacturing method thereof to solve the problems raised in the background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A thermal spraying intelligent control system, comprising: A central controller, configured to integrate sensing data and physical models to achieve multi-parameter coordinated adjustment of gas flow, spray gun movement, and suspension supply; A multi-parameter sensing module, configured to collect flame temperature, suspension flow rate, atomization air pressure, and substrate surface temperature in real time; A motion execution mechanism, configured to control the six-degree-of-freedom movement of the spray gun and the rotation of the substrate; A process parameter database, configured to store nozzle structure parameters, suspension physical properties, and target coating thickness values.

[0006] In the thermal spraying intelligent control system of the present invention, wherein, the central controller integrates: A spraying trajectory planning module, configured to generate a path based on the three-dimensional model of the substrate and adapt to uneven walls; A dynamic parameter compensation module, configured to adjust the ratio of gas and combustion-supporting gas in real time in response to sensing data.

[0007] For the intelligent thermal spraying control system of the present invention, wherein the spraying trajectory planning module performs the following operations: By importing the three-dimensional and / or two-dimensional model of the workpiece and identifying the wall surface curvature mutation region; Automatically reduce the moving speed of the spray gun in the region where the identified radius is less than the preset value.

[0008] For the intelligent thermal spraying control system of the present invention, wherein the multi-parameter sensing module includes: A two-color infrared pyrometer configured to measure the temperature of the flame core region with an accuracy of ±20°C; An ultrasonic suspension concentration sensor configured to on-line detect the fluctuation of the solid content.

[0009] To achieve the above object, the present invention also provides a suspension thermal spraying process control method, which is applied to the above intelligent thermal spraying control system. The process control method includes the following steps: Including the following steps: Step S1: Establish a suspension evaporation kinetic model; Step S2: Calculate the atomizing air pressure setting value based on the suspension evaporation kinetic model to ensure that the particle size D p ≤10μm and the particle proportion > 80%.

[0010] For the suspension thermal spraying process control method of the present invention, it further includes the following steps: Step S3: Construct a coating growth rate equation.

[0011] For the suspension thermal spraying process control method of the present invention, dynamically control the gas flow rate: Based on the flame temperature setting value T0; When the measured temperature T < T0 - 50°C, increase the C2H2 flow rate in proportion, ΔQ = K t (T0 - T)².

[0012] For the suspension thermal spraying process control method of the present invention, perform the following for uneven walls: Switch to the high-frequency pulse spraying mode in the groove area, and the switching period ≤ 0.1s; Synchronously increase the carrier gas pressure to 120 - 150% of the standard value.

[0013] To achieve the above object, the present invention also provides a suspension thermal spraying manufacturing process, including: Phase 1: Substrate pretreatment: Perform sandblasting treatment to make the surface roughness Ra = 5 - 8μm; Preheat to 380 ± 10°C; Stage 2: Layered spraying: The first layer is formed by high-speed scanning at 80 mm / s to form a porous bottom layer; The outer layer is densified by low-speed scanning at 50 mm / s.

[0014] The suspension thermal spraying manufacturing process of the present invention, wherein the manufacturing process further includes on-line quality closed-loop control: After every 2 mm of coating thickness is completed, start the laser thickness gauge to scan the surface; If the thickness variance σ² > 0.25, automatically repeat the spraying of the current layer; When the proportion of unmelted particles detected > 5%, increase the flame temperature by 30 °C.

[0015] Compared with the prior art, the beneficial effects of the present invention: Through the central controller, the integration of sensing data and physical models is realized, and the coordinated adjustment of many parameters such as gas flow, spray gun movement, suspension supply, flame temperature, suspension flow, atomization air pressure, substrate surface temperature, spray gun movement, and substrate rotation is realized. The global scheduling of multiple subsystems is realized, the isolation of the overall control system is reduced, and the collaborative response efficiency of multiple subsystems is significantly improved. Brief description of the drawings

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is the logic diagram away from the control system of the present invention.

[0018] Figure 2 It is the internal structure of the nozzle adopted by the control system of the present invention.

[0019] Figure 3 It is the detection logic flow chart of the closed-loop system of the present invention. Specific embodiments

[0020] In the description, claims, and drawings of the present invention, terms such as "first", "second", "third", and "fourth" are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0022] "Plurality" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0023] Moreover, terms indicating directions such as "up", "down", "left", "right", "upper end", "lower end", "longitudinal", etc. are all referenced based on the attitude position of the device or equipment described in this solution during normal use.

[0024] In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are partial embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0025] Embodiment 1 This embodiment discloses a Figure 1 thermal spraying intelligent control system as shown in a central controller configured to integrate sensing data and physical models to achieve multi-parameter coordinated adjustment of gas flow, spray gun movement, and suspension supply; a multi-parameter sensing module configured to collect flame temperature, suspension flow rate, atomization air pressure, and substrate surface temperature in real time; a motion execution mechanism configured to control the six-degree-of-freedom movement of the spray gun and the rotation of the substrate; The process parameter database is configured to store nozzle structure parameters, physical properties of the suspension, and target coating thickness values; Among them, the nozzle adopts a circumferential multi-port batching structure, such as Figure 2 shown, ensuring that the suspension can be evenly distributed 360 degrees outside the ejected ion beam, guaranteeing the uniformity of spraying. Compared with the structure of single-side liquid outlet, it can effectively avoid the splashing waste of the suspension outside the beam due to inertia and the interaction between droplets. The specific structure of this nozzle includes a lining sleeve 10, an outer lining sleeve 20 sleeved outside the lining sleeve 10, and a replaceable nozzle ring 30 coaxially connected to the outlet of the outer lining sleeve 20; the inner cavity of the lining sleeve 10 is used to coaxially install the electrode needle 100 and eject the gas. Specifically, there is a circulation flow channel 40 for coolant circulation between the lining sleeve 10 and the outer lining sleeve 20 to prevent the overall temperature of the nozzle from being too high.

[0026] Furthermore, the front end of the lining sleeve 10 has an end portion with both the inner diameter and the outer diameter narrowing synchronously. The front end of this end portion coaxially extends with a hollow and equal-diameter connecting shaft portion 101. The outer side wall of the connecting shaft portion 101 is coaxially threadedly connected to the inner wall of the front end of the outer lining sleeve 20. On the inner wall of the front end of the outer lining sleeve 20, there is a compression flow channel 201 with a diameter gradually narrowing forward. The rear end of the compression flow channel 201 is equal in diameter to the inner cavity of the connecting shaft portion 101 to ensure the smooth compression of the high-speed ion beam, reduce the interference of the turbulent flow, and ensure the initial ejection speed.

[0027] Furthermore, on the outer side wall of the outer lining sleeve 20, there is a radial liquid inlet nozzle 50. The channel 501 inside the liquid inlet nozzle 50 is L-shaped and its horizontal end faces the replaceable nozzle ring 30. The inner cavity of the nozzle ring 30 forms a docking flow channel 31 that docks with the channel 501. And an annular flow channel 32 is coaxially provided inside the nozzle ring 30. And there are a plurality of liquid outlet ports 33 circumferentially on the inner side wall of the nozzle, all of which communicate with the annular flow channel 32; among them, the diameter of the inner cavity of the nozzle ring 30 gradually increases axially backward, so that the ejected ion beam quickly diffuses after passing through the compression flow channel 201, increasing the coverage diameter of the ion beam. And in order to ensure the carrying and mixing effect of the ion beam, the liquid outlet ports are located at the position of the rear one-third of the inner cavity of the nozzle ring 30.

[0028] In addition, the nozzle ring 30 is coaxially threadedly connected to the inner wall of the installation groove 34 provided on the front end face of the outer lining sleeve 20. The front port of the compression flow channel 201 is located on the bottom surface of the installation groove 34, and the outlet diameter of the compression flow channel 201 is the same as the inlet diameter of the inner cavity of the nozzle ring 30. Among them, the thermal expansion coefficients of the lining sleeve 10 and the nozzle ring 30 are both greater than that of the outer lining sleeve 20, so as to strengthen the connection strength and sealing strength by using the waste heat during operation, and avoid excessive assembly gaps among the three resulting in liquid leakage and loosening.

[0029] This system integrates sensing data and physical models through a central controller, achieving coordinated adjustment of many parameters such as gas flow rate, spray gun movement, suspension supply, flame temperature, suspension flow rate, atomization air pressure, substrate surface temperature, spray gun movement, and substrate rotation. It realizes global scheduling of multiple subsystems, reduces the isolation of the overall control system, and significantly improves the collaborative response efficiency of multiple subsystems.

[0030] In the intelligent thermal spraying control system of the present invention, the central controller integrates: A spray trajectory planning module, configured to generate a path based on the three-dimensional model of the substrate and adapt to uneven wall surfaces; A dynamic parameter compensation module, configured to adjust the ratio of gas and combustion-supporting gas in real time in response to sensing data.

[0031] In the intelligent thermal spraying control system of the present invention, the spray trajectory planning module performs the following operations: By importing the three-dimensional and / or two-dimensional model of the workpiece and identifying the abrupt change region of the wall surface curve; Automatically reduce the moving speed of the spray gun in the region where the identified radius is less than the preset value; Three-dimensional model identification of the abrupt change region + curvature response deceleration can solve the problem of the disconnection between motion control and process parameters in the traditional system, and avoid the drawback of uneven coating coverage of the substrate surface groove.

[0032] In the intelligent thermal spraying control system of the present invention, the multi-parameter sensing module includes: A two-color infrared pyrometer, configured to measure the temperature of the flame core region with an accuracy of ±20°C; An ultrasonic suspension concentration sensor, configured to online detect the fluctuation of the solid content.

[0033] Embodiment 2 The present invention also provides a suspension thermal spraying process control method, which is applied to the above intelligent thermal spraying control system. The process control method includes the following steps: Including the following steps: Step S1: Establish a suspension evaporation kinetics model. Specifically, the model can adopt: In the formula, represents the change rate of the droplet diameter with time, with the unit of micrometer per second (μm / s), D p : The instantaneous droplet diameter, with the unit of micrometer (μm), t: Time (unit: s), k g : The gas-phase thermal conductivity, with the unit of watt per meter kelvin (W / m·K), ρp : Suspension density (unit: kg / m³), c p : Specific heat capacity at constant pressure of the suspension (unit: J / kg·K), B m : Mass transfer number, a dimensionless parameter, and its expression is , where Y F,s is the mass fraction of fuel vapor on the droplet surface, and Y F,∞ is the mass fraction of fuel vapor in the environment; Step S2: Calculate the set value of the atomizing air pressure based on the suspension evaporation kinetic model to ensure that the particle size D p ≤10 μm and the particle proportion > 80%.

[0034] The suspension thermal spraying process control method of the present invention further includes the following steps: Step S3: Construct a coating growth rate equation, which is specifically: In the formula, represents the change rate of the coating thickness with time, in units of micrometers per second (μm / s), and the scanning speed is executed by the servo motor, h represents the coating thickness, in units of micrometers (μm), represents the particle mass flow rate, in units of grams per second (g / s), represents the deposition efficiency, a dimensionless parameter, θ represents the angle between the spray gun axis and the normal of the substrate surface (angle of incidence), in units of degrees (°), k v represents the volume conversion coefficient, in units of cubic meters per gram second (m³ / (g·s)); The coating growth rate equation reveals the quantitative relationship between the coating thickness growth rate, the mass flow rate, and the angle of incidence. cosθ reflects that the vertical incidence is optimal, and the production control logic is as shown in Table 1 below: The suspension thermal spraying process control method of the present invention dynamically controls the gas flow rate: Based on the set value of the flame temperature T0; When the measured temperature T < T0 - 50 °C, the C2H2 flow rate is increased in geometric proportion, ΔQ = K t (T0 - T)²; ΔQ = K t In (T0 - T)²: ΔQ: Adjustment amount of acetylene (C2H2) flow rate (unit: L / min), K t: Temperature - flow conversion coefficient (unit: L / min·℃²), calibrated through nozzle characteristic experiments, T0: Target flame temperature (unit: ℃), T: Measured flame temperature (unit: ℃).

[0035] When the temperature difference |T0 - T| ≤ 50℃, linear adjustment (ΔQ ∝ |T0 - T|); when |T0 - T| > 50℃, quadratic adjustment (ΔQ ∝ (T0 - T)²) is performed to implement a quadratic compensation mechanism, so that rapid compensation can be obtained at large temperature differences. For example, when the temperature drops suddenly by 100℃, the gas increment reaches 2 - 4 times that of the linear mode; it also serves the purpose of preventing overshoot, making the adjustment amount automatically attenuate when approaching the target temperature and recovering faster than traditional PID control. The production control logic is as shown in Tables 2 and 3 below: For the suspension thermal spraying process control method described in the present invention, for uneven walls, the following is performed: Switch to the high - frequency pulse spraying mode in the groove area, and the switching period ≤ 0.1s; Synchronously increase the carrier gas pressure to 120 - 150% of the standard value.

[0036] Example 3 This example provides a suspension thermal spraying manufacturing process, including: Stage 1: Substrate pretreatment: Sandblasting treatment makes the surface roughness Ra = 5 - 8μm. Compared with traditional sandblasting with Ra = 3 - 10μm, it can improve the bonding strength of nickel - based superalloys or titanium alloys; Pre - heat to 380 ± 10℃ to eliminate micro - cracks caused by the difference in thermal expansion coefficients between the substrate and the coating, and at the same time activate the surface oxide diffusion layer (such as ) to enhance the chemical bonding force; Stage 2: Layer - by - layer spraying: The first layer is formed by high - speed scanning at 80mm / s to form a porous bottom layer, so that when the molten droplets impact the substrate, shear fracture occurs instead of complete spreading, forming 15 - 20% controllable pores; The outer layer is densified by low - speed scanning at 50mm / s to slow down the speed so that the molten droplets can fully spread and close the pores through capillary filling effect.

[0037] For the suspension thermal spraying manufacturing process described in the present invention, the manufacturing process also includes on - line quality closed - loop control, specifically as Figure 3 shown: After every 2mm coating thickness is completed, start the laser thickness gauge to scan the surface; If the thickness variance σ² > 0.25, automatically repeat the spraying of the current layer; When the proportion of unfused particles detected is > 5%, increase the flame temperature by 30°C.

[0038] It should be understood that those of ordinary skill in the art can make improvements or transformations according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A thermal spraying intelligent control system, characterized in that, Including: A central controller, configured to integrate sensing data and physical models to achieve multi-parameter coordinated adjustment of gas flow, spray gun movement, and suspension supply; A multi-parameter sensing module, configured to collect flame temperature, suspension flow rate, atomization air pressure, and substrate surface temperature in real time; A motion execution mechanism, configured to control the six-degree-of-freedom movement of the spray gun and the rotation of the substrate; A process parameter database, configured to store nozzle structure parameters, suspension physical properties, and target coating thickness values.

2. The thermal spraying intelligent control system according to claim 1, wherein The central controller integrates: A spray trajectory planning module, configured to generate a path based on the three-dimensional model of the substrate and adapt to uneven wall surfaces; A dynamic parameter compensation module, configured to adjust the ratio of gas and combustion-supporting gas in real time in response to sensing data.

3. The thermal spraying intelligent control system according to claim 2, characterized in that The spray trajectory planning module performs the following operations: By importing the three-dimensional and / or two-dimensional model of the workpiece and identifying the sudden change area of the wall surface curve; Automatically reduce the moving speed of the spray gun in the area where the recognition radius is less than the preset value.

4. The intelligent thermal spraying control system according to claim 1, wherein The multi-parameter sensing module includes: A two-color infrared pyrometer, configured to measure the temperature of the flame core area with an accuracy of ±20°C; An ultrasonic suspension concentration sensor, configured to detect the fluctuation of the solid content online.

5. A method for controlling a suspension thermal spraying process, which applies the thermal spraying intelligent control system described in any one of claims 1-4, characterized in that, Including the following steps: Step S1: Establish a suspension evaporation kinetic model; Step S2: Calculate the set value of the atomizing air pressure based on the suspension evaporation kinetics model to ensure that the particle size D p ≤ 10 μm and the particle proportion > 80%.

6. The suspension thermal spraying process control method according to claim 5, characterized in that, It also includes the following steps: Step S3: Construct a coating growth rate equation.

7. The method for controlling the suspension thermal spraying process according to claim 6, wherein Dynamically control the gas flow rate: Based on the set value T0 of the flame temperature; When the measured temperature T < T0 - 50°C, the flow rate of C2H2, ΔQ, increases geometrically by ΔQ = K t (T0 - T)².

8. The method for controlling the suspension thermal spraying process according to claim 7, wherein For uneven wall surfaces, execute: Switch to the high-frequency pulse spraying mode in the groove area, and the switching period ≤ 0.1 s; Synchronously increase the carrier gas pressure to 120-150% of the standard value.

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