A method and system for additive manufacturing online laser power stability monitoring

Abstract

The application discloses a kind of additive manufacturing online laser power stability monitoring method and system.The application first calibrates laser, and establishes power-voltage calibration library covering full light power range by pre-calibration model with 1W as interval;In the process of additive manufacturing, real-time acquisition monitoring signal, discard the unstable signal of each melting path initial ramping section and tail end down section, accurately calculate the voltage value of current layer stable state monitoring signal;According to the set power of current layer, get the calibration voltage from calibration library, directly calculate voltage variation rate as power variation rate, compare with pre-set threshold to judge power stability.The application directly calculates variation rate by voltage parameter, avoids table lookup error and delay, realizes real-time monitoring with better than 0.2% accuracy in full power range, and is compatible with dot matrix printing and other short-time scenarios, significantly improves the consistency and traceability of additive manufacturing process.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a method and system for online laser power stability monitoring in additive manufacturing. Background Technology

[0002] In additive manufacturing, online laser power monitoring is a crucial process control technology. Its core role is to ensure the accuracy, stability, and traceability of energy input. By capturing the actual power output data of the laser in real time and dynamically comparing it with preset process parameters, the system can instantly compensate for power deviations caused by factors such as equipment temperature drift and optical attenuation, thereby maintaining a constant thermal field in the molten pool and fundamentally ensuring the uniformity of the internal quality and the consistency of mechanical properties of the formed parts. Simultaneously, this technology also serves as a vital line of defense for equipment health management and anomaly early warning. Any abnormal power fluctuations can be quickly identified and trigger protection mechanisms, effectively preventing the generation of batches of defective products. Furthermore, the power data recorded throughout the process provides a complete and traceable "energy history" for part quality certification, forming a key cornerstone for transitioning additive manufacturing from "open-loop production" to "closed-loop intelligent control."

[0003] Existing methods for monitoring laser power stability judge power deviations within a certain fluctuation range, considering those within the set range as normal and those exceeding the set range as abnormal. However, due to the unavoidable fluctuations in the acquired monitoring signals, the fluctuation range for power judgment is usually set too large, resulting in poor detection accuracy. Secondly, under the same conditions, the fluctuation amounts of different power levels are not consistent; generally, higher power levels also have larger fluctuation amounts. Using the same fluctuation range for all power levels as a standard for judging whether the power is normal is inaccurate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an additive manufacturing laser power stability monitoring method that can achieve high-precision online monitoring across the entire power range, effectively eliminate monitoring signal ramp-up and downshoot interference, judge power stability by voltage change rate, and is compatible with short-term printing scenarios such as dot matrix printing, thereby avoiding the monitoring inaccuracy problems caused by inconsistent judgment standards, rough signal processing, and misjudgment of short-term operating conditions in the prior art.

[0005] To solve the above-mentioned technical problems, embodiments of the present invention provide the following technical solution: 1. A method for online laser power stability monitoring in additive manufacturing, comprising the following steps: The laser is calibrated. After the laser is calibrated, the power is precalibrated using a pre-set precalibration model. Based on the precalibration results, the monitoring signal precalibration amplitude voltage corresponding to the power at 1W intervals is given. A power-voltage calibration library is established as a benchmark for judging whether the real-time power is stable during the additive manufacturing process. During the additive manufacturing process, the laser power monitoring signal of each printed layer is collected in real time, the amplitude voltage of the laser power monitoring signal is calculated, the signals of the melt channel corresponding to each power and all melt channels are matched, the unstable signals collected at the beginning and end of the melt channel are discarded, and the average value of the monitoring signal voltage is calculated by selecting the monitoring signal under stable conditions to obtain the stable state monitoring signal voltage value of the current layer. Based on the current layer's set power, the corresponding calibration voltage value is retrieved from the power-voltage calibration library. The voltage change rate between the current layer's stable state monitoring signal voltage value and the calibration voltage value is calculated, and this voltage change rate is used as the power change rate. Set a power change rate threshold, compare the calculated power change rate with the threshold, determine whether the laser power is stable based on whether it exceeds the power change rate threshold, and give the specific power and change rate of each layer.

[0006] Furthermore, the specific method for establishing the power-voltage calibration library includes: Based on the pre-calibrated model, printing was performed at different power levels, and monitoring signals were collected. Calculate the monitoring signal amplitude voltage corresponding to all power levels; Interpolate the monitoring signal amplitude voltage corresponding to a 1W power interval to form a calibration library covering the entire output power range of the laser.

[0007] Furthermore, the discarding of unstable signals collected at the beginning and end of the melt channel specifically includes: for each printed melt channel, identifying the initial ramp-up stage and the final down-rush stage of its monitoring signal, discarding the data points of the initial and final stages of the melt channel, selecting only the middle section signal of each melt channel in a stable state to calculate the average voltage, and then averaging the average voltage of all melt channels in the layer to obtain the stable state monitoring signal voltage value of the current layer.

[0008] Furthermore, the formula for calculating the voltage change rate is: Voltage change rate = ; in The current layer's steady-state monitoring signal voltage value. The voltage change rate is the calibration voltage value corresponding to the current layer's set power, which is obtained from the calibration library. The voltage change rate is equivalent to the power change rate.

[0009] Furthermore, the accuracy of the power change rate is 0.2%.

[0010] Furthermore, when the additive manufacturing process consists of dot matrix printing with a single printing time lower than a preset time threshold, the method also includes an adaptive compensation step: pre-calculating the systematic deviation between the amplitude voltage of the monitoring signal collected under different power and different printing times and the corresponding calibration voltage in the calibration library, and establishing a power-printing time-voltage deviation compensation table; in real-time monitoring, when the single light emission time of the current printing layer is lower than the preset time threshold, the compensation table is queried according to the set power and actual light emission time of the current layer, and the reference voltage obtained from the calibration library is reduced accordingly to compensate for the measurement deviation caused by the monitoring signal not entering a stable state.

[0011] Furthermore, it also includes a real-time power status feedback step: the obtained power stability result is fed back in real time. When the laser power is determined to be unstable, the system issues an alarm signal and automatically adjusts the preset output power command of the laser for subsequent printing layers according to the calculated voltage deviation or power deviation.

[0012] Furthermore, it also includes a data recording step: recording the real-time monitoring signal voltage value, steady-state voltage value, calculated voltage change rate, corresponding real-time power value, and stability judgment result for each printed layer.

[0013] Furthermore, the interpolation of the monitoring signal amplitude voltage corresponding to the 1W power interval specifically includes: Discrete data pairs are formed by multiple discrete calibration power points and their corresponding amplitude voltages. A continuous mapping function between power and voltage is fitted using linear interpolation or spline interpolation algorithms. Based on the continuous mapping function, the amplitude voltage of the monitoring signal corresponding to every 1W power interval is calculated from the minimum output power to the maximum output power of the laser, forming a calibration library covering the entire output power range.

[0014] The present invention also proposes an online laser power stability monitoring system for additive manufacturing to implement the method described in any of the above claims, comprising: Laser calibration module, used to calibrate the laser before monitoring begins; The pre-calibration module is used to execute the pre-calibration model and build a power-voltage calibration library with 1W intervals; The real-time signal acquisition and processing module is used to acquire and monitor signals in real time during the additive manufacturing process, accurately match signals from each melt channel, discard unstable signal segments, and calculate the average voltage of the monitoring signals in a stable state. The power calculation and stability judgment module is used to query the calibration library to obtain the calibration voltage according to the current layer's set power, calculate the voltage change rate between the average voltage of the current layer's stable state monitoring signal and the calibration voltage as the power change rate, compare the change rate with a preset threshold, and output the stability judgment result as well as the power and change rate of each layer. The feedback and recording module is used to trigger alarms or compensation actions when the power is unstable, and to record the voltage, power and rate of change data throughout the process.

[0015] The beneficial effects of the above-described technical solution of the present invention are as follows: (1) Real-time acquisition of monitoring signals of each layer during laser additive manufacturing and power stability judgment can obtain laser energy intensity in real time, realize real-time monitoring and accurate recording of power changes during manufacturing.

[0016] (2) Using the power change rate as the basis for judging power stability, rather than the amount of power change, greatly improves the accuracy of power monitoring. The laser power stability monitoring method described in this invention calculates the power change rate with an accuracy of less than 0.2%.

[0017] (3) Before monitoring the laser power stability, a pre-calibration model is used to pre-calibrate the power as a judgment benchmark, so that all power stability judgments have an accurate and unified benchmark value, ensuring the accuracy of power stability monitoring.

[0018] (4) Before monitoring the power stability of different printing devices, pre-calibration printing is performed. Each monitoring device has a power stability evaluation benchmark value to avoid the influence of printing devices or environment on the results.

[0019] (5) After analyzing and summarizing the characteristics of a large number of power monitoring signals, a stable signal is selected when calculating the amplitude voltage of the monitoring signal to avoid the influence of abnormal signal fluctuations on the results; the accurate average amplitude of the monitoring signal is obtained, which further improves the accuracy of the power monitoring method.

[0020] (6) Power can be accurately determined even for dot matrix printing with a very short printing time; this method can accurately determine the power stability of single-layer dot matrix printing with a printing time of 0.1 seconds. Attached Figure Description

[0021] Figure 1 The overall flowchart of the online monitoring method for laser power stability provided by the present invention is shown.

[0022] Figure 2 The flowchart shows the laser power pre-calibration method provided by the present invention.

[0023] Figure 3 This is a schematic diagram of the climbing phenomenon exhibited by the laser power monitoring signal collected in the initial stage of this invention. Detailed Implementation

[0024] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0025] Example 1 This invention uses the rate of change of power as the basis for judging power stability, and this rate of change of power is directly calculated from the voltage parameter, without the need to first convert it to a power value before calculating the rate of change. This is because in the calibration library, voltage and power have a linear correspondence, and the rate of change of voltage is equivalent to the rate of change of power. By establishing a power-voltage calibration library for all powers within the laser's output power range at 1W intervals, and through a complete process of real-time acquisition of monitoring signals, calculation of stable voltage values, comparison with calibration voltages, calculation of voltage change rate (as the rate of change of power), judgment of power stability, and real-time feedback of power status, real-time and accurate monitoring of the stability of any laser power within the entire range can be achieved.

[0026] Specifically, the present invention provides the following technical solution: A method for online laser power stability monitoring in additive manufacturing includes the following five steps: Step 1: Laser Calibration Before starting laser power stability monitoring, calibrate the laser to ensure accurate initial power. Calibration can be performed using an external absolute power meter to measure the laser at multiple key power points, and the internal control parameters of the laser can be adjusted to keep the output power error within the allowable range.

[0027] Step 2: Power pre-calibration, establishing a power-voltage calibration library with 1W intervals. After laser calibration, power pre-calibration is performed using a pre-set pre-calibration model. Based on the pre-calibration model, printing is performed at different powers, and monitoring signals are collected. The amplitude voltage of the monitoring signal corresponding to all powers is calculated. The amplitude voltage of the monitoring signal corresponding to a 1W power interval is interpolated to form a calibration library covering the entire output power range of the laser. Based on the pre-calibration results, the pre-calibrated amplitude voltage of the monitoring signal at 1W power intervals is given as a benchmark for judging whether the real-time power is stable during additive manufacturing. Analysis of a large amount of experimental data shows that the average error of the benchmark amplitude voltage obtained by pre-calibration is 0.1W, which is highly accurate.

[0028] Step 3: Real-time acquisition of monitoring signals and calculation of steady-state monitoring signal voltage values. During the additive manufacturing process, the laser power monitoring signal of each printed layer is acquired in real time. To address the instability of the acquired laser power monitoring signal amplitude, the amplitude voltage of the laser power monitoring signal is calculated by precisely matching the signals of each power-corresponding melt path and all melt paths. Unstable signals acquired at the beginning and end of the melt path due to detector adaptability issues are discarded. The average value of the monitoring signal voltage is calculated by precisely selecting the monitoring signal under stable conditions to obtain the stable state monitoring signal voltage value of the current layer.

[0029] Specifically, the monitoring signal exhibits a ramp-up phenomenon in its initial stage, as does the initial stage of each printed run, meaning the monitoring signal amplitude slowly rises to a stable value. The higher the laser's output power, the more pronounced the ramp-up phenomenon in the initial stage; lower power results in no noticeable ramp-up. Given a sufficiently long data length, even with ramp-up, the monitoring signal will eventually reach a stable state. Discarding the ramp-up signals from the initial stages of monitoring signal acquisition and each run, and instead calculating the average amplitude voltage using the stable state of the monitoring signal, avoids the impact of ramp-up on the calculation results. Furthermore, the calculation of the average value also avoids the influence of occasional abnormal signals, resulting in a more accurate amplitude voltage calculation. Additionally, unstable signals due to detector adaptability also exist at the end of each printed run, and these are also discarded.

[0030] Step 4: Calculate the power change rate using voltage parameters Based on the current layer's set power, the corresponding calibration voltage value (i.e., the monitoring signal voltage that should be output under ideal conditions at this set power) is retrieved from the power-voltage calibration library. The rate of change of voltage between the current layer's stable-state monitoring signal voltage value and the calibration voltage value is calculated, and this rate of change is taken as the power change rate. The formula for calculating the rate of change of voltage is: Voltage change rate = ; in The current layer's steady-state monitoring signal voltage value. The voltage change rate is the calibration voltage value corresponding to the current layer's set power, retrieved from the calibration library. This voltage change rate is equivalent to the power change rate. By directly calculating the voltage change rate, the computational delay and potential interpolation errors caused by first looking up the power value in a table and then calculating the change rate are avoided, making monitoring faster and more accurate.

[0031] Step 5: Assess power stability and provide real-time feedback. A power change rate threshold is set, and the voltage change rate (as the power change rate) calculated in step four is compared with the threshold. Whether the laser power is stable is determined based on whether it exceeds the power change rate threshold, and the specific power and change rate for each layer are given. Statistical analysis of a large amount of data shows that the fluctuation amount of different powers at the same time under the same conditions varies greatly; the higher the power, the greater the fluctuation amount. Therefore, the method of judging power stability by the magnitude and range of power fluctuations cannot be applied to all powers. However, the power fluctuation amount is relatively consistent with the power change rate; therefore, the power change rate is used as the basis for judging power stability. After collecting and statistically analyzing a large number of monitoring signals with different powers, printing times, and melt path lengths, the accuracy of the power change rate calculated by the laser power stability monitoring method described in this invention is less than 0.2%.

[0032] Furthermore, to address the possibility of additive manufacturing processes consisting of dot matrix prints with exceptionally short single-print times, this invention also provides an adaptive compensation scheme. When the acquired monitoring signals are all from the ramp-up phase before reaching a stable state, the difference between the amplitude voltage of the monitoring signals at different powers and print times and the calibration voltage is statistically analyzed. For scenarios with significant differences, power and print time ranges are defined, and the reference voltage in the calibration library is reduced accordingly within each range based on the calculation results. This method can accurately determine the power stability of dot matrix prints with a single-layer print time of 0.1 seconds.

[0033] This invention also provides an online laser power stability monitoring system for additive manufacturing to implement the above-described method, comprising: a laser calibration module, a pre-calibration module, a real-time signal acquisition and processing module, a power calculation and stability decision module, and a feedback and recording module. The core function of the power calculation and stability decision module is to: obtain the calibration voltage from the calibration library based on the current layer's set power; calculate the voltage change rate between the current layer's stable state voltage and the calibration voltage as the power change rate; and compare this change rate with a preset threshold.

[0034] Example 2 The process for online monitoring of laser power stability is as follows: Figure 1 The core key points are: (1) Before starting laser power stability monitoring, calibrate the laser to ensure that the initial power of the laser is accurate.

[0035] (2) After laser calibration, power pre-calibration is performed using a pre-set pre-calibration model, as follows: Figure 2 Based on the pre-calibration results, a pre-calibration amplitude voltage of the monitoring signal with a power interval of 1W is given as a benchmark for judging whether the real-time power is stable during the additive manufacturing process.

[0036] (3) Through statistical analysis of a large amount of data, it is known that under the same conditions and at the same time, the fluctuation of different powers varies greatly, and the larger the power, the larger the fluctuation usually is. Therefore, the method of judging power stability by the magnitude and range of power fluctuation cannot be applied to all powers. However, the power fluctuation is relatively consistent with the rate of change of power. Therefore, the rate of change of power is used as the basis for judging power stability: set a threshold for the rate of change of power, calculate the rate of change of power of each layer in the additive manufacturing process, and judge whether the laser power is stable based on whether it exceeds the threshold of the rate of change of power, and give the specific power and rate of change of each layer.

[0037] (4) For the unstable amplitude of the collected laser power monitoring signal: When calculating the amplitude voltage of the laser power monitoring signal, accurately match the signals of each power corresponding to the melt channel and all melt channels, discard the unstable signals collected at the beginning and end of the melt channel due to the detector adaptability problem, accurately select the monitoring signal under stable state to calculate the average value of the monitoring signal voltage, avoid the influence of the regularity and irregularity of the signal on the calculation results, and improve the accuracy of the method.

[0038] (5) In the case that the additive manufacturing process may consist of dot matrix printing with a very short single printing time, and the collected monitoring signals are all uphill signals that have not reached a stable state: Statistically analyze the difference between the amplitude voltage of the monitoring signal and the calibration voltage for different power and printing time. For scenarios with large differences, divide the power range and printing time range, and reduce the reference voltage in the calibration library accordingly based on the calculation results in each range.

[0039] The specific process of pre-calibration is as follows: Figure 2 As shown, the specific explanation is as follows: (1) Based on the pre-calibrated model, print at different power levels and collect monitoring signals.

[0040] (2) Calculate the monitoring signal amplitude voltage corresponding to all power levels, and interpolate the monitoring signal amplitude voltage corresponding to the 1W power interval.

[0041] (3) After analyzing a large amount of experimental data, it is known that the average error of the reference amplitude voltage obtained by pre-calibration is 0.1W, which is highly accurate.

[0042] After collecting and analyzing a large number of monitoring signals from different scenarios, the characteristics of the monitoring signals are summarized as follows: (1) There will be a ramp-up phenomenon in the initial stage of the monitoring signal, and there will also be a ramp-up phenomenon in the initial stage of each printed melt channel, that is, the amplitude of the monitoring signal slowly rises to a stable value, such as Figure 3 As shown.

[0043] (2) The higher the output power of the laser, the more obvious the climbing phenomenon in the initial stage of the monitoring signal. When the power is low (less than 200W), there is no obvious climbing phenomenon.

[0044] Given a sufficiently long data length, the monitoring signal will reach a stable state even with a ramp-up. By discarding the ramp-up signals from the initial stages of monitoring signal acquisition and each melting stage, and instead using the average amplitude voltage calculated from the stable state of the monitoring signal, the impact of the ramp-up on the calculation results can be avoided. Furthermore, the calculation of the average value can also avoid the influence of occasional abnormal signals on the calculation results, resulting in a more accurate amplitude voltage calculation.

[0045] If the additive manufacturing process consists of dot matrix printing with very short single print times, the collected monitoring signals may all be from the ramp-up phase before reaching a stable state. In this case, the calculated signal amplitude will be too low. If power changes are judged based on calibration data, normally stable conditions will be incorrectly identified as abnormal attenuation. The solution to this problem is to statistically analyze the difference between the monitoring signal amplitude voltage and the calibration voltage for different power levels and print times. For scenarios with large differences, divide the process into power ranges and print time ranges, and within each range, reduce the reference voltage in the calibration library accordingly based on the calculation results.

[0046] Through the collection and statistical analysis of a large number of monitoring signals with different power, printing time, and melt path length, the laser power stability monitoring method described in this invention calculates the power change rate with an accuracy of less than 0.2%.

[0047] The advancement of the method of this invention lies in: (1) Real-time acquisition of monitoring signals of each layer during laser additive manufacturing and power stability judgment can obtain laser energy intensity in real time, realize real-time monitoring and accurate recording of power changes during manufacturing.

[0048] (2) Using the power change rate as the basis for judging power stability, rather than the amount of power change, greatly improves the accuracy of power monitoring. The laser power stability monitoring method described in this invention calculates the power change rate with an accuracy of less than 0.2%.

[0049] (3) Before monitoring the laser power stability, a pre-calibration model is used to pre-calibrate the power as a judgment benchmark, so that all power stability judgments have an accurate and unified benchmark value, ensuring the accuracy of power stability monitoring.

[0050] (4) Before monitoring the power stability of different printing devices, pre-calibration printing is performed. Each monitoring device has a power stability evaluation benchmark value to avoid the influence of printing devices or environment on the results.

[0051] (5) After analyzing and summarizing the characteristics of a large number of power monitoring signals, a stable signal is selected when calculating the amplitude voltage of the monitoring signal to avoid the influence of abnormal signal fluctuations on the results; the accurate average amplitude of the monitoring signal is obtained, which further improves the accuracy of the power monitoring method.

[0052] (6) Power can be accurately determined even for dot matrix printing with a very short printing time; this method can accurately determine the power stability of single-layer dot matrix printing with a printing time of 0.1 seconds.

[0053] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for online laser power stability monitoring in additive manufacturing, characterized in that, Includes the following steps: The laser is calibrated. After the laser is calibrated, the power is precalibrated using a pre-set precalibration model. Based on the precalibration results, the monitoring signal precalibration amplitude voltage corresponding to the power at 1W intervals is given. A power-voltage calibration library is established as a benchmark for judging whether the real-time power is stable during the additive manufacturing process. The specific methods for establishing the power-voltage calibration library include: Based on the pre-calibrated model, printing was performed at different power levels, and monitoring signals were collected. Calculate the monitoring signal amplitude voltage corresponding to all power levels; Interpolate the monitoring signal amplitude voltage corresponding to a 1W power interval to form a calibration library covering the entire output power range of the laser; In the additive manufacturing process, the laser power monitoring signal of each printed layer is collected in real time, the amplitude voltage of the laser power monitoring signal is calculated, the signals of each power corresponding to the melt channel and all melt channels are matched, the unstable signals collected at the beginning and end of the melt channel are discarded, and the average voltage of the monitoring signal in the stable state is calculated to obtain the stable state monitoring signal voltage value of the current layer; the discarding of the unstable signals collected at the beginning and end of the melt channel specifically includes: for each printed melt channel, the initial ramp-up stage and the final down-rush stage of its monitoring signal are identified, the data points of the initial stage and the final stage of the melt channel are discarded, only the middle section signal of each melt channel in the stable state is selected to calculate the average voltage, and the average voltage of all melt channels in the layer is averaged again to obtain the stable state monitoring signal voltage value of the current layer; Based on the current layer's set power, the corresponding calibration voltage value is retrieved from the power-voltage calibration library. The voltage change rate between the current layer's stable state monitoring signal voltage value and the calibration voltage value is calculated, and this voltage change rate is used as the power change rate. The formula for calculating the voltage change rate is: Voltage change rate = ; in The current layer's steady-state monitoring signal voltage value. The voltage change rate is the calibration voltage value corresponding to the current layer's set power, obtained from the calibration library; the voltage change rate is equivalent to the power change rate. Set a power change rate threshold, compare the calculated power change rate with the threshold, determine whether the laser power is stable based on whether it exceeds the power change rate threshold, and give the specific power and change rate of each layer.

2. The method for online laser power stability monitoring in additive manufacturing according to claim 1, characterized in that, The accuracy of the power change rate is 0.2%.

3. The method for online laser power stability monitoring in additive manufacturing according to claim 1, characterized in that, When the additive manufacturing process consists of dot matrix printing with a single printing time lower than a preset time threshold, the method further includes an adaptive compensation step: pre-calculating the systematic deviation between the amplitude voltage of the monitoring signal collected under different power and different printing times and the corresponding calibration voltage in the calibration library, and establishing a power-printing time-voltage deviation compensation table; in real-time monitoring, when the single light emission time of the current printing layer is lower than the preset time threshold, the compensation table is queried according to the set power and actual light emission time of the current layer, and the reference voltage obtained from the calibration library is reduced accordingly to compensate for the measurement deviation caused by the monitoring signal not entering a stable state.

4. The method for online laser power stability monitoring in additive manufacturing according to claim 1, characterized in that, It also includes a real-time power status feedback step: the power stability result is fed back in real time. When the laser power is determined to be unstable, the system issues an alarm signal and automatically adjusts the preset output power command of the laser for subsequent printing layers according to the calculated voltage deviation or power deviation.

5. The method for online laser power stability monitoring in additive manufacturing according to claim 1, characterized in that, It also includes a data recording step: recording the real-time monitoring signal voltage value, steady-state voltage value, calculated voltage change rate, corresponding real-time power value, and stability judgment result for each printed layer.

6. The method for online laser power stability monitoring in additive manufacturing according to claim 1, characterized in that, The interpolation of the monitoring signal amplitude voltage corresponding to the 1W power interval specifically includes: Discrete data pairs are formed by multiple discrete calibration power points and their corresponding amplitude voltages. A continuous mapping function between power and voltage is fitted using linear interpolation or spline interpolation algorithms. Based on the continuous mapping function, the amplitude voltage of the monitoring signal corresponding to every 1W power interval is calculated from the minimum output power to the maximum output power of the laser, forming a calibration library covering the entire output power range.

7. An online laser power stability monitoring system for additive manufacturing to implement the method according to any one of claims 1 to 6, characterized in that, include: Laser calibration module, used to calibrate the laser before monitoring begins; The pre-calibration module is used to execute the pre-calibration model and build a power-voltage calibration library with 1W intervals; The real-time signal acquisition and processing module is used to acquire and monitor signals in real time during the additive manufacturing process, accurately match signals from each melt channel, discard unstable signal segments, and calculate the average voltage of the monitoring signals in a stable state. The power calculation and stability judgment module is used to query the calibration library to obtain the calibration voltage according to the current layer's set power, calculate the voltage change rate between the average voltage of the current layer's stable state monitoring signal and the calibration voltage as the power change rate, compare the change rate with a preset threshold, and output the stability judgment result as well as the power and change rate of each layer. The feedback and recording module is used to trigger alarms or compensation actions when the power is unstable, and to record the voltage, power and rate of change data throughout the process.

Images