Composite manufacturing method based on interlayer alternate additive polishing

Abstract

The invention discloses a composite manufacturing method based on interlayer alternate additive polishing, and belongs to the technical field of additive manufacturing and surface finishing composite processes, the method comprises the following steps: sequentially depositing a kth layer and a (k + 1) th layer of additive layer on a substrate or a formed body, and carrying out in-situ polishing treatment on the (k + 1) th layer of exposed surface, by controlling the quantitative relation between the polishing depth and the thickness of an additional material layer, the ratio of the additional material to the polishing energy density and the included angle of a scanning path, the next additional material layer is preheated in combination with polishing waste heat, the interlayer temperature gradient is controlled, the steps are executed circularly till a workpiece is completed, and meanwhile a polishing skipping mechanism is arranged for a supporting structure layer and an initial layer; and the polishing energy is adaptively adjusted through real-time monitoring of the surface roughness. According to the method, the limitation that traditional additive manufacturing and post-treatment are disjointed is broken through, interlayer defect real-time repair and residual stress regulation are achieved, the surface quality and density of the component can be remarkably improved, the surface roughness is reduced, and the manufacturing efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing and surface finishing composite process technology, specifically relating to an additive-polishing composite manufacturing method based on interlayer timing control, which is applicable to the manufacturing of precision parts made of metal, ceramic and polymer materials. Background Technology

[0002] With the increasing demands for performance in complex metal components from fields such as aerospace, high-end mold making, and biomedicine, laser additive manufacturing has become a crucial method for high-performance manufacturing due to its advantages, including eliminating the need for molds, high material utilization, and the ability to rapidly realize complex structures. Its typical process includes steps such as metal powder deposition, laser melting, and solidification, building three-dimensional solid parts layer by layer.

[0003] Despite its many advantages, laser additive manufacturing still faces some key technical challenges, particularly in the following areas: The problem of interlayer defect accumulation is serious: In traditional additive manufacturing, if the surface of a certain layer is rough or contains microcracks, these defects will be inherited and amplified layer by layer, ultimately affecting the overall accuracy and strength of the part. Common defects include molten pool ripples, spatter particle adhesion, and uneven cooling shrinkage.

[0004] Surface quality does not meet the requirements: Due to the rapid cooling and solidification of the laser molten pool, it is very easy to form a stepped structure and irregular melt edge on the surface, resulting in high roughness (usually Ra>10 μm). A lot of post-processing is required to meet the surface finish requirements of aerospace-grade parts.

[0005] High risk of residual stress accumulation: Laser heating has the characteristics of high gradient and local instantaneous heat. As the number of layers increases, thermal stress gradually accumulates, which can easily cause warping, cracks or even manufacturing failure, especially in thin-walled structures and closed cavities.

[0006] Current post-processing is disconnected from the manufacturing process: Current surface treatment methods, such as integral laser remelting, mechanical grinding, and electropolishing, are usually carried out separately after the forming is completed. This not only results in a lengthy process and high energy consumption, but also makes it difficult to reach and process complex internal structures, affecting the service performance of parts.

[0007] The process is highly uncontrollable and has large repeatability errors: the decoupling of manufacturing and polishing operations requires the workpiece to be transferred between different platforms, which leads to problems such as hot-cold switching and clamping errors, which are not conducive to high-precision control and automated integration.

[0008] In recent years, some researchers have attempted to use laser remelting, short-pulse lasers, or assisted plasma techniques for polishing modification in order to improve surface quality. However, these techniques are all post-processing methods after a specific layer or the entire component has been completed in additive manufacturing. Their core limitation lies in the severe temporal and spatial misalignment between the manufacturing process (material deposition and forming) and quality control / polishing intervention: there is a lack of real-time quality perception and control during the process, and post-processing can only act on the final or current outermost surface, failing to retrospectively address defects and inhomogeneities generated in real-time during manufacturing in the interior of the deposited layer (such as pores and lack of fusion) and interlayer regions (such as step effects, heat-affected zones, and residual stress distribution). This leads to the fundamental problem of "real-time decoupling" between the manufacturing process and quality control, severely lacking the ability to dynamically perceive, respond to, and control the critical interlayer states.

[0009] It is evident that existing laser additive manufacturing technologies still face a series of challenges when dealing with complex structures and high service performance requirements, such as the separation of manufacturing and quality control, the inability to repair defects in real time, and the uncontrollability of interlayer stress. There is an urgent need for a new additive manufacturing method that integrates manufacturing and polishing processes, has real-time repair capabilities, and achieves closed-loop feedback control, in order to achieve high-quality, low-defect, and high-efficiency additive manufacturing. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides an additive polishing composite manufacturing method with controllable timing and optimized quality and efficiency. After depositing two layers of additives using laser powder additive manufacturing process, a laser with time-division output from the same source laser as the additives is used to polish a certain depth. The residual heat from polishing is used to preheat the next additive layer, and the additive steps are repeated for repeated periodic additive polishing to reduce the accumulation of thermal stress.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: A composite manufacturing method based on interlayer alternating additive polishing includes the following periodic timing control steps: Step 1: Deposit the k-th additive layer on the substrate or pre-formed body, where k is an integer ≥ 1; Step 2: Deposit the (k+1)th additive layer on the kth additive layer; Step 3: Polish the exposed surface of the (k+1)th additive layer; Step 4: Let k = k + 2, and repeat steps 1 to 3 until the workpiece manufacturing is completed.

[0012] Furthermore, in step three, when performing in-situ polishing, the polishing depth h satisfies: 0.1H≤h≤0.8H, where H is the average thickness of a single additive layer.

[0013] Furthermore, the additive manufacturing process and parameters for steps one to three are as follows: laser power of 50-500W, laser scanning speed of 0.5-3.0m / s, and powder feeding rate for directional energy deposition of 10-50g / min. Furthermore, in step three, in-situ polishing is performed using a laser that is output from the same source laser as the additive laser, with the linear energy density during polishing being 25%-35% of the linear energy density during additive laser production.

[0014] Furthermore, the angle between the polishing scan path and the additive scanning path Calculated using the following formula:

[0015] in, The linear energy density during laser polishing. This represents the linear energy density during additive manufacturing.

[0016] Furthermore, the time interval between the end of polishing step three and the beginning of step three in the next cycle. satisfy:

[0017] In the formula: The melting point of the material. The surface temperature at the end of polishing. The material cooling rate coefficient, It can be calibrated using an infrared thermal imager.

[0018] Furthermore, after step three is completed, the residual heat from polishing is used to preheat the next additive layer. The initial deposition temperature of the next additive layer is higher than the final deposition temperature of the polishing layer. Double, and maintain interlayer temperature gradient satisfy:

[0019] In the formula: Temperature field distribution function , representing any point in the additive-polishing composite structure The temperature is z, and z is the thickness of the additive polishing layer in the vertical direction.

[0020] Furthermore, for the support structure layer, if the kth or k+1th layer is a support structure, the polishing step of that cycle is skipped, and one cycle refers to completing steps one to three.

[0021] Furthermore, after every three cycles, an additional fine polishing of the cross-layer area is added, with a fine polishing depth of 2-3 times the thickness of a single layer. One cycle refers to completing steps one through three.

[0022] Furthermore, it also includes real-time monitoring of the surface roughness Ra value of the (k+1)th layer; when Ra > threshold R max At that time, the polishing energy density increases by 20%-50%.

[0023] Compared with the prior art, the present invention has at least the following beneficial technical effects: (1) This invention significantly improves the efficiency of additive-polishing composite manufacturing by time-division multiplexing of the same source laser, while saving manufacturing costs. It also achieves coordinated control of the interlayer timing of additive-polishing composite, and breaks through the problem of interlayer defect accumulation. That is, by polishing the k+1 layer immediately after every two layers are deposited, the interlayer defects are repaired in real time, eliminating the drawback of defect amplification layer by layer in additive manufacturing, and reducing the surface roughness accumulation effect by more than 80%. At the same time, the residual heat of polishing is used to directly preheat the next additive layer, reducing the energy consumption of repeated heating and improving the thermal cycle efficiency. The interlayer temperature gradient control reduces the accumulation of thermal stress by 60%, and significantly suppresses warping deformation.

[0024] (2) By controlling the polishing energy density to 20%-40% of that of additive manufacturing, and combining the scanning path angle of 45°-90°, the additive directional texture is completely eliminated, and the surface roughness Ra of the workpiece is reduced to below 3μm.

[0025] (3) The polishing method of the present invention has an adaptive real-time feedback mechanism. The roughness Ra value is monitored in real time by the molten pool sensor to dynamically correct the polishing parameters, solve the problem of process instability caused by material fluctuations, and greatly improve the finished product qualification rate.

[0026] (4) This invention improves both manufacturing efficiency and quality through timing control, utilization of residual heat, and adaptive feedback. Timing control integrates polishing into the manufacturing cycle, eliminating workpiece transfer and secondary clamping, thus shortening the manufacturing cycle; utilization of interlayer residual heat reduces energy consumption by about 40%, and adaptive feedback realizes a closed loop of "manufacturing-inspection-correction", which greatly reduces the scrap rate. Attached Figure Description

[0027] Figure 1 This is a flowchart of the method described in this invention; Figure 2 This is a schematic diagram of the surface roughness feedback mechanism in the process of this invention; Figure 3 This is a schematic diagram of the additive polishing composite manufacturing apparatus provided by the present invention; Figure 4 This is a schematic diagram of the additive polishing composite manufacturing apparatus provided by the present invention.

[0028] In the attached diagram: 1-Computer; 2-Laser generator; 3-Powder feeder; 4-Powder distributor; 5-Powder pipe; 6-Column; 7-Base; 8-Temperature sensor; 9-Ambient oxygen sensor; 10-Molten pool sensor; 11-Spectrometer sensor; 12-Clamping part; 13-Sealed chamber; 14-X-axis track motor; 15-X-axis track support; 16-First X-axis track lead screw; 17-Second X-axis track lead screw; 18-Y-axis track motor; 19-Y-axis track support; 20-Y-axis track lead screw; 21-Z-axis track motor; 22-Z-axis track support; 23-Z-axis track lead screw. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0031] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or may be interposed with another element. The terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] Example 1 Reference Figure 1A composite manufacturing method based on interlayer alternating additive polishing achieves synergistic optimization of additive and polishing processes through periodic timing control, including the following periodic timing control steps: Step 1: Fix the substrate or pre-formed body with clamping parts. Adjust the laser generator 2 to the target position using the x-track bracket 15, y-track bracket 19, and z-track bracket 22. Start the argon gas filling system to replace the air in the sealed chamber and monitor the data from the ambient oxygen sensor 9 in real time. When the concentration is ≥100ppm, continue argon filling; when the concentration is <100ppm, close the inlet and outlet ports. The computer 1 controls the powder feeder 3 to deposit the k-th additive layer powder on the substrate or pre-formed body through the powder distributor 4 and powder pipe 5. Then, the laser generator 2 melts the additive layer powder at a preset power and scanning speed. The specific additive process parameters are: the laser power for powder bed melting is 50-500W, the laser scanning speed is 0.5-3.0m / s, the powder feeding rate for directional energy deposition is 10-50g / min, the melt pool sensor 10 monitors the melt pool penetration depth and linear energy density in real time, and if the melt pool penetration depth and linear energy density exceed the threshold, the laser generator 2 is paused. The temperature sensor 8 measures the substrate temperature in real time. Step 2: After the additive manufacturing of the kth additive layer is completed and the ambient temperature of the sealed chamber drops to the preset temperature (40-45℃), deposit the (k+1)th additive layer on the kth additive layer. Furthermore, in the additive manufacturing processes of steps one and two, the powder layer thickness and powder spreading speed are controlled to ensure the smooth progress of the additive manufacturing stage. The single-layer powder thickness H and the powder particle size satisfy the following:

[0034] In the formula: The particle size corresponding to 10% and 90% cumulative powder distribution. The compaction compensation during the additive manufacturing process is typically 2-5 mm; while the powder spreading speed is important to meet the rheological properties of the powder material. Satisfy the following formula:

[0035] In the formula: This represents the particle size corresponding to 50% of the cumulative powder distribution. It is the acceleration due to gravity. This refers to the angle of repose of the powder material; specific values ​​can be found online. The coefficient of friction between the powder and the substrate.

[0036] Furthermore, the laser melting performed after the powder material is laid in step one follows the powder melting kinetics model, and the theoretical molten pool penetration depth can be calculated by computer 1. The molten pool sensor 10 monitors the actual molten pool penetration depth h and the actual linear energy density in real time, as well as the theoretical molten pool penetration depth. and actual molten pool penetration depth The relation is:

[0037] In the formula: For laser power, Thermal conductivity, The initial temperature of the substrate. For real-time substrate temperature, The thermal diffusivity of additive powder materials, For laser dwell time, The radius of the light spot is... It continued to melt at that time, when Immediately turn off the laser to stop melting.

[0038] Actual linear energy density The stability criterion is ,in, The material density of the additive powder; The formula for calculating the actual linear energy density of additive powder is:

[0039] in, For laser scanning speed, until linear energy density The process proceeds to the next step only after the stability threshold is met. During this determination process, temperature sensor 8 and molten pool sensor 10 monitor data in real time and transmit it to computer 1 for calculation. The value is determined, and stability is judged according to the stability criterion. If it exceeds the specified range, melting is stopped, and the laser is restarted to continue melting when the substrate temperature returns to a suitable value (120-150℃).

[0040] Step 3: After completing the deposition of the (k+1)th layer, the exposed surface of the (k+1)th additive layer is polished in situ using a laser with time-division output from the same source laser as the additive layer; the polishing depth h1 is calculated using formula (5), and the laser power, scanning speed, and scanning time are adjusted according to the polishing depth h1. The polishing process in this step is energy-assisted laser polishing; the relationship between the polishing depth h1 and the thickness H of the additive single layer is as follows:

[0041] In the formula: This is the depth adjustment factor, 0.1≤ ≤0.8, When the value is less than 0.1, the polishing energy is insufficient, and traces of molten pool fluctuation remain. When the value is greater than 0.8, excessive melting leads to a decrease in interlayer bonding strength and material bonding strength. With depth adjustment coefficient They are negatively correlated, specifically:

[0042] In the formula: The material attenuation coefficient is determined by the material's inherent properties. It is the theoretical maximum bonding strength of the material.

[0043] Furthermore, for this step, a laser polishing process using a laser from the same source as the additive manufacturing laser with time-division output is adopted, and the linear energy density of the laser polishing is set. The calculation formula is:

[0044] In the formula: The linear energy density during laser polishing. For linear energy density during additive manufacturing, The energy conversion coefficient is preferably 0.25-0.35.

[0045] Furthermore, to ensure the elimination of directional lines in additive scanning, the angle between the polishing scanning path and the additive scanning path is specified to satisfy the following relationship:

[0046] In the formula: To reduce the angle between the laser polishing path and the additive manufacturing scanning path, To avoid the angle being too small, which would prevent the texture from being effectively covered, This refers to the scanning path direction vector during additive manufacturing. This is the scanning path direction vector during laser polishing, designed to control the included angle. To eliminate directional lines generated during additive manufacturing, computer 1 determines the polishing path at an optimal angle. The optimal solution for this angle is:

[0047] in, The optimal polishing path angle is dynamically calculated by the computer to maximize the texture elimination effect.

[0048] During this process, a multi-axis guide rail laser system is used for angle adjustment, and the computer calculates the optimal solution according to equation (9). Then, it drives the x-track motor 14, y-track motor 18, and z-track motor 21, causing the laser generator 2 to rotate. After angling, scanning is performed to eliminate textures and create polished curved surfaces.

[0049] Reference Figure 2 Furthermore, throughout the polishing process, surface data is monitored in real time, and the surface roughness of the (k+1)th layer is obtained through the spectral sensor 11. value:

[0050] In the formula: The first data collected by the spectral sensor Height data of each point (unit: ), The average height of all measurement points. This represents the number of sampling points in a single scan by the sensor.

[0051] when > Threshold At that time, the polishing energy density is adaptively increased as follows:

[0052] In the formula: This is the adaptive adjustment coefficient, typically 0.2 ≤ γ ≤ 0.5; Let be the minimum achievable roughness of the material, and be an inherent property of the material itself. The maximum roughness is set; For the adaptive new polishing energy density, The original polishing density before adaptation, and .

[0053] Step 4: Let k = k + 2, and repeat steps 1 to 3 until the workpiece is completed, where k is an integer ≥ 1. After step 3 of each cycle is completed, residual heat remains in the sealed chamber; this residual heat is used to preheat the next additive layer. After the final additive layer is completed, two consecutive polishing processes are performed, with the first polishing depth being 0.5H and the second polishing depth being 0.2H.

[0054] During the cycle, the interval time and the temperature of preheating using residual heat need to be monitored simultaneously. When polishing ends, computer 1 starts timing and sends a command to temperature sensor 8 to record the surface temperature at the end of polishing. , surface temperature After being transmitted to Computer 1, Computer 1 calculates the time interval. After an interval Then, computer 1 issues an instruction to start a new round of additive polishing from step one, with the time interval between the end of polishing in step three and the start of step one in the next cycle. satisfy:

[0055] In the formula: The melting point of the additive powder material. The workpiece surface temperature at the end of polishing. The material cooling rate coefficient of additive powder.

[0056] Furthermore, after each cycle, during the preheating of the starting additive layer for the new cycle using residual heat from the in-situ polishing step, the initial deposition temperature of the additive layer and the final polishing temperature satisfy the following:

[0057] In the formula: The initial deposition temperature of a new additive manufacturing cycle (i.e., the surface temperature at which the (k+2)th layer begins deposition), and the terminal-initial temperature coefficient. This is an inherent property of the material itself, specifically the optimal initial-final temperature coefficient of the material is determined experimentally and calculated. The interlayer temperature gradient... satisfy:

[0058] In the formula: Temperature field distribution function , representing any point in the additive-polishing composite structure The temperature is z, and z is the thickness of the additive polishing layer in the vertical direction.

[0059] Furthermore, the method for adjusting specific layers during the cycle is as follows: when k=1, polishing is skipped and the second layer is deposited directly; and if the kth or k+1th layer is a support structure, polishing is skipped. Furthermore, after every three cycles, an additional cross-layer fine polishing is added. Specifically, this means polishing the second layer after the first and second additive manufacturing layers; polishing the fourth layer after the third and fourth additive manufacturing layers; and fine polishing the sixth layer after the fifth and sixth additive manufacturing layers, and so on, to begin a new three-cycle process. The depth of cross-layer fine polishing in this step... Relationship with single-layer thickness and material removal volume for:

[0060]

[0061] Where: interlayer thickness parameter In polishing, the specific number of layers is 2 or 3, and the layer relationship is determined experimentally; The polishing energy threshold, This represents the polishing energy density.

[0062] This method breaks through the limitations of traditional additive manufacturing and post-processing, enabling real-time repair of interlayer defects and control of residual stress. It can significantly improve the surface quality and density of components, reduce surface roughness, and increase manufacturing efficiency. It is suitable for the manufacturing of precision parts made of metals, ceramics, and polymers.

[0063] Example 2 Reference Figure 3 and Figure 4 The present invention also provides a composite manufacturing apparatus based on interlayer alternating additive polishing, including a base 7, a sealed chamber 13 mounted on the base 7, a multi-axis guide rail laser system and a detection and sensing system disposed in the sealed chamber 13, an additive powder feeding system disposed outside the sealed chamber 13, and a computer 1.

[0064] The multi-axis guide rail laser system includes an x-axis track bracket 15 mounted on a base 7. The x-axis track bracket 15 is equipped with an x-axis track motor 14 and an x-axis rolling screw. The x-axis rolling screw includes a first x-axis track screw 16, a second x-axis track screw 17, and an x-axis nut on the screw. The first x-axis track screw 16 and the second x-axis track screw 17 are mounted on the x-axis track bracket 15 at both ends. One end of the first x-axis track screw 16 and the second x-axis track screw 17 passes through a screw bearing support seat and is connected to the output shaft of the two x-axis track motors through a coupling. The two x-axis track motors work synchronously. The x-axis track bracket 15 is equipped with a y-axis track bracket 19 that can move and slide along the first x-axis track screw 16 and the second x-axis track screw 17. Specifically, the y-axis track bracket 19 is fixed on the x-nut. The y-axis track bracket 19 is equipped with a y-axis track motor 18 and a y-axis rolling screw. The y-axis rolling screw includes a y-axis track screw 20 and a y-axis nut. Both ends of the y-axis track screw 20 are installed on the y-axis track bracket 19. One end of the y-axis track screw 20 passes through the screw bearing support seat and is connected to the output shaft of the y-axis track motor 18 through a coupling. A z-axis track bracket 22, movable along the z-axis track screw 20, is mounted on the z-axis track bracket 19. The z-axis track bracket 22 is fixed to the z-nut. A z-axis track motor 21 and a z-axis rolling screw are mounted on the z-axis track bracket 22. The z-axis rolling screw includes a z-axis track screw 23 and a z-axis nut. Both ends of the z-axis track screw 23 are mounted on the z-axis track bracket 22. One end of the z-axis track screw 23 passes through a screw bearing support and is connected to the output shaft of the z-axis track motor 21 via a coupling. A laser mounting bracket, movable along the z-axis track screw 23, is mounted on the z-axis track bracket 22. Specifically, the laser mounting bracket is fixedly connected to the z-axis nut. A servo motor-driven rotating device is mounted on the lower end face of the laser mounting bracket. This rotating device drives the laser generator 2 to rotate. The x-track bracket 15 is fixedly connected to the column 6 by bolts. The column 6 and the side wall opposite to the z-axis track bracket 22 are fixedly connected to a clamping part 12. The clamping part 12 is also fixedly connected to the column 6 by reinforcing ribs. The clamping part 12 is used to clamp the substrate or the formed body. Computer 1 is connected to laser generator 2 via wires. The parameters of laser generator 2 can be adjusted by the built-in software of laser generator 1 to switch between additive manufacturing mode and polishing mode. Computer 1 is also connected to x-track motor 14, y-track motor 18, and z-track motor 21 via wires to drive the supports in each direction to move in the target direction.

[0065] The detection sensing system includes a temperature sensor 8, an ambient oxygen sensor 9, a molten pool sensor 10, and a spectral sensor 11 mounted on the column 6. All four sensors are connected to the computer 1 via wires for real-time feedback of monitoring data. The temperature sensor 8 and ambient oxygen sensor 9 are mounted on the side wall of the column 6, while one end of the molten pool sensor 10 and the spectral sensor 11 is mounted on the top of the column 6, with the signal receiving end located above the clamping part 12. An additive powder feeding system is located on the left side of the sealed chamber 13. This system includes a powder feeder 3, a powder distributor 4, and a powder pipeline 5. The powder feeder 3 is connected to the computer 1 via wires and can receive computer commands. It transfers additive powder material through the powder distributor 4 and the powder pipeline 5. The output port of the powder feeder 4 is connected to the inlet of the powder distributor 5, and the outlet of the powder distributor 5 is connected to the powder pipeline 5. The end of the powder pipeline 5 is located above the clamping part 12.

[0066] Temperature sensor 8 has two probes for measuring the ambient temperature of the sealed chamber and the substrate temperature. Ambient oxygen sensor 9 is used to measure the oxygen concentration inside the sealed chamber 13. Molten pool sensor 10 is used to measure the molten pool depth and linear energy density. Spectral sensor 11 is used to measure the spectral wavelength characteristics of the polished area.

[0067] The term "constituting of" in describing a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, parts, or steps herein also contemplates embodiments that are essentially composed of such elements, components, parts, or steps. The use of the term "may" herein is intended to indicate that any described attribute included by "may" is optional.

[0068] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0069] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A composite manufacturing method based on interlayer alternating additive polishing, characterized in that, This includes the following periodic timing control steps: Step 1: Deposit the k-th additive layer on the substrate or pre-formed body, where k is an integer ≥ 1; Step 2: Deposit the (k+1)th additive layer on the kth additive layer; Step 3: Polish the exposed surface of the (k+1)th additive layer; Step 4: Let k = k + 2, and repeat steps 1 to 3 until the workpiece manufacturing is completed.

2. The composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, In step three, when performing in-situ polishing, the polishing depth h satisfies: 0.1H≤h≤0.8H, where H is the average thickness of a single additive layer.

3. The composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, The additive manufacturing process and parameters for steps one to three are as follows: laser power is 50-500W, laser scanning speed is 0.5-3.0m / s, and powder feeding rate for directional energy deposition is 10-50g / min.

4. The composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, In step three, in-situ polishing is performed using a laser that is output from the same source laser as the additive laser, with the linear energy density during polishing being 25%-35% of the linear energy density during additive laser production.

5. The composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, Angle between laser polishing scanning path and additive manufacturing scanning path Calculated using the following formula: in, The linear energy density during laser polishing. This represents the linear energy density during additive manufacturing.

6. The composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, The time interval between the end of polishing in step three and the beginning of step one in the next cycle. satisfy: In the formula: The melting point of the material. The surface temperature at the end of polishing. The material cooling rate coefficient, It can be calibrated using an infrared thermal imager.

7. The composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, After step three is completed, the residual heat from polishing is used to preheat the next additive layer. The initial deposition temperature of the next additive layer is higher than the final deposition temperature of the polishing layer. Double, and maintain interlayer temperature gradient satisfy: In the formula: Temperature field distribution function , representing any point in the additive-polishing composite structure The temperature is z, and z is the thickness of the additive polishing layer in the vertical direction.

8. A composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, For the support structure layer, if the kth or k+1th layer is a support structure, skip the polishing step of that cycle. One cycle refers to completing steps one through three.

9. A composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, After every three cycles, an additional fine polishing of the cross-layer area is added, with a fine polishing depth of 2-3 times the thickness of a single layer. One cycle refers to completing steps one through three.

10. A composite manufacturing method based on interlayer alternating additive polishing according to claim 1, characterized in that, It also includes real-time monitoring of the surface roughness Ra value of the (k+1)th layer, when Ra > threshold R max At that time, the polishing energy density increases by 20%-50%.

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