Precise control device and method for wire feeding in laser-arc hybrid wire and arc additive manufacturing process

Abstract

The application provides a wire feeding precision control device and method for a laser-arc hybrid wire feeding additive manufacturing process, comprising a wire feeder, a welding gun wire guide tube, a laser head, a sensor support, a force signal sensor and a data collector; the wire feeder is connected with the wire guide tube; the wire guide tube is connected with the laser head; the laser head is coaxially coupled with the wire guide tube inside; the wire feeder is connected with the sensor support; the sensor support is connected with the force signal sensor; and the force signal sensor is connected with the data collector. The application can precisely control the contact force of the wire in the processing of the laser-arc hybrid wire feeding additive manufacturing equipment, quantize the wire feeding speed parameter, and improve the processing stability and quality of the equipment.

Description

Technical Field

[0001] This invention relates to the field of laser-arc composite wire feeding additive manufacturing technology, specifically to a precise wire feeding control device and method for the laser-arc composite wire feeding additive manufacturing process. Background Technology

[0002] Laser-arc hybrid wire-feed additive manufacturing involves coupling a focused laser beam with an electric arc to melt a metal wire, depositing it layer by layer to form the desired geometry. Compared to traditional electric arc-feed additive manufacturing methods, laser-arc hybrid wire-feed additive manufacturing offers significant advantages such as controllable heat input, high additive speed, minimal thermal deformation, and high forming accuracy. In recent years, it has been widely used in the high-performance manufacturing of complex components.

[0003] Laser-arc composite wire-feed additive manufacturing is a complex, dynamic process involving multiple physical fields. The quality of the printed parts is affected by numerous disturbances, such as wire feeding errors, mismatched process parameters, and fluctuations in protective gas flow. These factors can lead to drastic changes in the molten pool, resulting in printing discontinuities, increased splattering, and other printing quality issues. Wire feeding is a key factor affecting the forming quality. When the wire feeding speed is too high, it exceeds the melting speed, causing unmelted wire to easily extend to the bottom of the molten pool, forming non-liquid bridges in the molten droplets, resulting in segmented burn-off, damaging the additive forming process, affecting surface quality, and interfering with laser focusing, thus disrupting the normal printing process. When the wire feeding speed is too slow, insufficient filler metal can occur, easily leading to edge biting. When the wire feeding speed is unstable, the formed part surface is prone to unevenness, inconsistent width, and coarse waveform. Therefore, to obtain high-quality laser-arc composite coaxial wire-feed additive manufacturing parts, precise control of wire feeding in the manufacturing process is essential to reduce or even eliminate forming defects.

[0004] Patent application document CN114633023A discloses a wire feeding control method, system and laser welding device for laser welding, which uses a wire status detection component to control the distance between the welding wire and the workpiece through computer vision assistance. However, this control method is only suitable for laser welding. In the additive manufacturing process, it is difficult to obtain the distance in multi-layer deposition, and the timeliness is low and the lag is serious, so it cannot achieve precise control.

[0005] In general, to leverage the high precision and high quality advantages of laser-arc composite wire feeding additive manufacturing, the corresponding wire feeding device needs to be intelligent and precise to enable reasonable and accurate wire feeding throughout the entire process and to cope with real-time changes in state parameters during the additive manufacturing process. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a precise wire feeding control device and method for laser-arc composite wire feeding additive manufacturing processes.

[0007] The laser-arc composite wire feeding additive manufacturing process precision control device provided by the present invention includes: a wire feeder, a welding torch wire guide tube, a laser head, a sensor bracket, a force signal sensor, and a data acquisition device;

[0008] The wire feeder is connected to the welding torch wire guide tube; the welding torch wire guide tube is connected to the laser head; the welding torch wire guide tube is coaxially coupled inside the laser head; the wire feeder is connected to the sensor bracket; the sensor bracket is connected to the force signal sensor; and the force signal sensor is connected to the data acquisition unit.

[0009] Preferably, the force signal sensor consists of a floating component and a fixed component; the floating component is connected to the wire feeder; the fixed component is connected to a fixed platform; the force signal sensor measures the force signal by the change in the relative distance between the floating component and the fixed component.

[0010] Preferably, it also includes: an IPC industrial control computer; the IPC industrial control computer is connected to the wire feeder; the IPC industrial control computer is connected to a data acquisition unit;

[0011] Preferably, it further includes: a force measuring test bench; the force measuring test bench has a measurement range of 0~30 N;

[0012] The laser-arc composite wire feeding additive manufacturing process precise wire feeding control method provided by the present invention comprises the following steps:

[0013] Step S1: Before additive manufacturing, the force signal sensor is calibrated to collect signals;

[0014] Step S2: Before additive manufacturing, the contact force information of the force signal sensor is obtained through a force testing bench;

[0015] Step S3: During the additive manufacturing process, the data acquisition unit collects the signals fed back by the force signal sensor in real time and analyzes the root mean square of the collected signals;

[0016] Step S4: During the additive manufacturing process, the data acquisition unit collects the signals fed back by the wire feeder in real time and analyzes the root mean square of the collected signals.

[0017] Step S5: Analyze the root mean square data of the force signal obtained by the data acquisition device and the root mean square data of the wire feeding speed of the wire feeder to obtain the contact force information and actual wire feeding speed information of the wire feeder.

[0018] Step S6: Based on the contact force information from the force signal sensor, the PID control algorithm is used in the IPC industrial control computer to process the data and control the wire feeding speed of the wire feeder.

[0019] Step S7: Based on the contact force information from the force signal sensor and the wire feeding speed information from the control wire feeder, precise control of wire feeding in the laser wire feeding additive manufacturing process is achieved.

[0020] Preferably, the contact force information in step S2 is the contact force between the wire and the bottom of the molten pool;

[0021] Preferably, step S2 includes:

[0022] Step S2.1: Based on the information from the force testing platform and the force information of the wire from the force signal sensor, the contact force signal of the wire inside the wire feeder is obtained through the force testing platform. The root mean square of the force signal is calibrated according to the changes in the force testing platform under different contact forces. The relationship curve between the contact force and the root mean square of the force signal is fitted to obtain the relationship curve information.

[0023] Step S2.2: Obtain the contact force information of the wire based on the relationship curve results.

[0024] Preferably, the expression for the root mean square in steps S3 and S4 is:

[0025]

[0026] Where RMS is the root mean square. Let i be the amplitude of the i-th sampling point. This represents the number of data points used for the root mean square.

[0027] Preferably, step S6 includes:

[0028] Based on the relationship curve results, determine whether the contact force information of the force signal sensor exceeds the set force data during the additive manufacturing process;

[0029] If the contact force is greater than the set force, the wire feeding speed is reduced by the IPC industrial control computer until the error between the contact force and the set force is within ±5%.

[0030] If the contact force is less than the set force, increase the wire feeding speed via the IPC industrial control computer until the error between the contact force and the set force is within ±5%.

[0031] Preferably, in step S6, the specific steps of the PID control algorithm for adjusting the wire feeding speed are as follows: when the error between the contact force and the set force exceeds ±5%, in order to adapt to the actual discrete-time sampling working mode, the PID controller is discretized on the IPC industrial control computer, and the sampling interval is set to... The deviation between the set contact force and the actual wire feeding contact force obtained in each step S5 is used as the input to the discrete PID controller. The output of the discrete PID controller is expressed by the following formula:

[0032]

[0033] in, It is a moment The amount of wire feeding speed control; This refers to the systematic error, which is the deviation between the set contact force and the actual wire feeding contact force. It is the accumulation of systematic errors; It is the rate of change of the systematic error; It is proportional gain; It is integral gain; It is the differential gain.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) This invention addresses the precise control of the contact force between the wire and the bottom of the molten pool during laser-arc composite wire feeding additive manufacturing. It aims to solve technical problems such as unstable droplet transition and poor forming quality caused by fluctuations in wire feeding speed. It belongs to the refined control method in the field of additive manufacturing. By collecting the contact force between the wire and the bottom of the molten pool in real time through a force signal sensor, and combining it with a PID control algorithm to dynamically adjust the wire feeding speed, a closed-loop feedback control of the wire feeding process is realized, which significantly improves the stability and forming quality of the additive manufacturing process.

[0036] (2) The force testing platform of the present invention is set to a measurement range of 0~30 N. This measurement range is determined according to the actual variation range of the contact force between the wire and the bottom of the molten pool during the laser arc composite wire feeding additive manufacturing process. It can cover the contact force fluctuation under normal working conditions and ensure the accuracy and reliability of calibration and measurement. At the same time, the setting of this range avoids the decrease in measurement sensitivity caused by the excessive range, and also avoids the problem of the range being too small to cover the actual working conditions, thus improving the adaptability and practicality of the force signal sensor. Attached Figure Description

[0037] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0038] Figure 1 This is a schematic diagram of the principle of the laser-arc composite wire feeding precision control device for additive manufacturing process based on force signal according to the present invention.

[0039] Figure 2 This is a schematic diagram of the precise wire feeding control method in the laser-arc composite wire feeding additive manufacturing process of the present invention;

[0040] In the diagram: 1—Wire feeder; 2—Welding torch wire guide tube; 3—Laser head; 4—Sensor bracket; 5—Force signal sensor; 6—Data acquisition unit; 7—IPC industrial control computer; 8—Force measurement test bench; 9—Fixed platform. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0042] Example

[0043] like Figure 1 The present invention provides a wire feeding precision control device for a laser-arc composite wire feeding additive manufacturing process based on force signals, comprising: a wire feeder 1, a welding torch wire guide tube 2, a laser head 3, a sensor bracket 4, a force signal sensor 5, and a data acquisition device 6.

[0044] The wire feeder 1 is connected to the welding torch wire guide tube 2; the welding torch wire guide tube 2 is connected to the laser head 3; the welding torch wire guide tube 2 is coaxially coupled inside the laser head 3; the wire feeder 1 is connected to the sensor bracket 4; the sensor bracket 4 is connected to the force signal sensor 5; the force signal sensor 5 is connected to the data acquisition unit 6.

[0045] The force signal sensor 5 is composed of a floating component 51 and a fixed component 52; the floating component 51 is connected to the sensor bracket 4; and the fixed component 52 is connected to the fixed platform 9.

[0046] The force signal sensor 5 measures the force signal by the change in the relative distance between the floating component 51 and the fixed component 52;

[0047] It also includes: an IPC industrial control computer 7; the IPC industrial control computer 7 is connected to the wire feeder 1; the IPC industrial control computer 7 is connected to the data acquisition unit 6;

[0048] It also includes: a force measuring test bench 8; the force measuring test bench 8 has a measuring range of 0~30 N;

[0049] In this embodiment of the invention, the force signal sensing-based wire feeding precision control device mainly includes a force signal sensor, a sensor bracket, and an IPC industrial control computer control system. This device is installed in the welding torch wire guide section between the laser head and the wire feeder of the laser-arc composite wire feeding equipment, ensuring accurate measurement of the contact force between the wire and the bottom of the molten pool.

[0050] In this embodiment of the invention, the sensor bracket is made of stainless steel and should be as close as possible to the laser head to ensure that the measured force signal is indeed the contact force of the wire at the end of the laser head. Furthermore, to reduce interference such as wire splashing, the device requires a sealed design.

[0051] In this embodiment of the invention, the IPC industrial computer control system in the precision wire feeding control device is mainly used to control the wire feeding speed and amount, the switching on and off of the laser, and to read and analyze the force signals received by the force signal sensor. Specifically, the wire feeding speed of the wire feeder is adjusted based on the analyzed data to ensure the process stability of the laser-arc composite wire feeding equipment during operation, thereby improving the forming quality and printing success rate. In this embodiment of the invention, the precision wire feeding control device uses a PID control algorithm to adjust the wire feeding speed. This algorithm is only a preferred wire feeding speed adjustment method for this invention and should not be considered as limiting the scope of the invention.

[0052] like Figure 2 The present invention also provides a method for precise control of wire feeding in a laser-arc composite wire feeding additive manufacturing process based on force signals, comprising the following steps:

[0053] Step S1: Before additive manufacturing, the force signal sensor is calibrated to collect signals;

[0054] Step S2: Before additive manufacturing, the contact force information of the force signal sensor is obtained through a force testing bench;

[0055] The contact force information in step S2 is the force between the wire and the bottom of the molten pool.

[0056] Step S2 includes:

[0057] Step S2.1: During the additive manufacturing process, when the laser head is in the working position, the filament is fed to the working plane of the force testing platform via a filament feeder to acquire the contact force data of the force testing platform. Based on the relative positional changes of the floating and fixed components of the force signal sensor, the force signal information of the force signal sensor is acquired by the data acquisition device, and the root mean square (RMS) data of the force signal is analyzed. The RMS data of the force signal under different contact forces are calibrated, and based on the least squares method, a relationship curve between the contact force and the RMS of the force signal is fitted to obtain the relationship curve information.

[0058] Step S2.2: Based on the relationship curve results, the force signal from the force signal sensor is used to measure the contact force between the wire and the bottom of the molten pool to obtain the contact force results of the wire during the additive manufacturing process.

[0059] Step S3: During the additive manufacturing process, the data acquisition unit collects the signals fed back by the force signal sensor in real time and analyzes the root mean square of the collected signals;

[0060] Step S4: During the additive manufacturing process, the data acquisition unit collects the signals fed back by the wire feeder in real time and analyzes the root mean square of the collected signals.

[0061] The root mean square expression is:

[0062]

[0063] Where RMS is the root mean square. For the first Amplitude at each sampling point, Therefore, the number of data points used for the root mean square is...

[0064] Step S5: Analyze the root mean square (RMS) data of the force signal obtained by the data acquisition device. Based on the relationship curve obtained in Step 2, convert the RMS data of the force signal into a contact force signal between the wire and the bottom of the molten pool. Analyze the RMS data of the wire feeding speed of the wire feeder to obtain the actual wire feeding speed information of the wire feeder. Integrate the actual wire feeding speed information to obtain the wire feeding amount information during the additive manufacturing process.

[0065] Step S6: Based on the contact force information from the force signal sensor, the PID control algorithm is used in the IPC industrial control computer to process the data and control the wire feeding speed of the wire feeder.

[0066] Step S6 includes:

[0067] Based on the contact force information obtained in step 5, by comparison, it is determined whether the contact force information of the force signal sensor in the additive manufacturing process exceeds the set force data;

[0068] If the contact force of the wire is greater than the set force of the IPC industrial control computer, the wire feeding speed will be reduced by the IPC industrial control computer until the error between the contact force and the set force is within ±5%.

[0069] If the contact force of the wire is less than the set force of the IPC industrial control computer, the wire feeding speed is increased through the IPC industrial control computer until the error between the contact force and the set force is within ±5%.

[0070] In step S6, the specific steps of the PID control algorithm for adjusting the wire feeding speed are as follows: When the error between the contact force and the set force exceeds ±5%, in order to adapt to the actual discrete-time sampling working mode, the PID controller is discretized on the IPC industrial control computer, and the sampling interval is set to... The deviation between the set contact force and the actual wire feeding contact force obtained in step S5 is used as the input to the discrete PID controller, and the output of the discrete PID controller is used as the wire feeding speed adjustment. The output of the discrete PID controller is expressed by the following formula:

[0071]

[0072] in, It is a moment The amount of wire feeding speed control; This refers to the systematic error, which is the deviation between the set contact force and the actual wire feeding contact force. It is the accumulation of systematic errors; It is the rate of change of the systematic error; It is proportional gain; It is integral gain; It is the differential gain.

[0073] Step S7: Based on the contact force information from the force signal sensor and the wire feeding speed information from the wire feeder, the wire is stably and continuously fed into the molten pool during the laser arc composite wire feeding additive manufacturing process. This avoids problems such as changes in the molten droplet transition form, poor additive surface quality, and numerous defects caused by fluctuations in wire feeding speed, thus achieving precise wire feeding control in the laser arc composite wire feeding additive manufacturing process.

[0074] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0075] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A control method for a precision wire feeding control device in a laser-arc composite wire feeding additive manufacturing process, characterized in that, The precise wire feeding control device for the laser arc composite wire feeding additive manufacturing process includes: a wire feeder (1), a welding torch wire guide tube (2), a laser head (3), a sensor bracket (4), a force signal sensor (5), and a data acquisition device (6). The wire feeder (1) is connected to the welding torch wire guide tube (2) and is used to transport the wire to the welding torch wire guide tube (2). The welding torch wire guide tube (2) is connected to the laser head (3); The laser head (3) has a coaxially coupled welding gun wire guide tube (2) inside, which is used to guide the wire to the processing area; The wire feeder (1) is connected to the sensor bracket (4); The sensor bracket (4) is connected to the force signal sensor (5) and is used to support and fix the force signal sensor (5). The force signal sensor (5) is connected to the data acquisition unit (6) and is used to transmit the detected force signal to the data acquisition unit (6). The force signal sensor (5) is composed of a floating component (51) and a fixed component (52); The floating component (51) is connected to the sensor bracket (4); The fixing component (52) is connected to the fixing platform; The force signal sensor (5) measures the force signal by the change in the relative distance between the floating component (51) and the fixed component (52); It also includes IPC industrial control computers (7); The IPC (7) is connected to the wire feeder (1) and is used to control the wire feeding speed of the wire feeder (1); The IPC industrial control computer (7) is connected to the data acquisition unit (6) and is used to receive and process force signal data from the data acquisition unit (6); It also includes a force testing platform (8); The force testing bench (8) has a measurement range of 0~30 N and is used to obtain contact force calibration information of the force signal sensor before additive manufacturing. The control method performs the following steps: Step S1: Before additive manufacturing begins, calibrate the force signal sensor's acquisition signal; Step S2: Before additive manufacturing begins, the contact force information of the force signal sensor is obtained through a force testing bench; Step S3: During the additive manufacturing process, the signal fed back by the force signal sensor is collected in real time by a data acquisition device, and the root mean square of the collected signal is analyzed. Step S4: During the additive manufacturing process, the signal fed back by the wire feeder is collected in real time by the data acquisition device, and the root mean square of the collected signal is analyzed. Step S5: Analyze the root mean square data of the force signal obtained by the data acquisition device and the root mean square data of the wire feeding speed of the wire feeder to obtain the contact force information of the wire and the actual wire feeding speed information during the wire feeding process. Step S6: Based on the contact force information measured by the force signal sensor, a PID control algorithm is used to process the data in the IPC industrial control computer to generate a wire feeding speed control command for the wire feeder. Step S7: Based on the contact force information and the control of the wire feeding speed, achieve precise control of wire feeding in the laser arc composite wire feeding additive manufacturing process.

2. The control method of the precision wire feeding control device for the laser-arc composite wire feeding additive manufacturing process according to claim 1, characterized in that, The contact force information obtained in step S2 is the contact force between the wire and the bottom of the molten pool.

3. The control method of the precision wire feeding control device for the laser-arc composite wire feeding additive manufacturing process according to claim 1, characterized in that, In steps S3 and S4, the expression for calculating the root mean square is: Where RMS is the root mean square. For the first Amplitude at each sampling point, Therefore, the number of data points used for the root mean square is...

4. The control method of the precision wire feeding control device for the laser-arc composite wire feeding additive manufacturing process according to claim 1, characterized in that, Step S2 includes: Step S2.1: Based on the measurement information from the force testing bench and the force information of the filament detected by the force signal sensor, the contact force signal of the filament in the filament feeder is obtained through the force testing bench; the change of the root mean square of the force signal under different contact forces is calibrated, and the relationship curve between the contact force and the root mean square of the force signal is fitted to obtain the relationship curve information; Step S2.2: Based on the relationship curve information, obtain the contact force results between the filament and the bottom of the molten pool during the additive manufacturing process.

5. The control method of the precision wire feeding control device for the laser-arc composite wire feeding additive manufacturing process according to claim 1, characterized in that, Step S6 includes: Based on the contact force information obtained in step S5, determine whether the contact force detected by the force signal sensor during the additive manufacturing process exceeds a preset force threshold. If the detected contact force is greater than the set force threshold, the wire feeding speed of the wire feeder is reduced by the IPC industrial control computer until the error between the contact force and the set force threshold is kept within ±5%. If the detected contact force is less than the set force threshold, the wire feeding speed of the wire feeder is increased by the IPC industrial control computer until the error between the contact force and the set force threshold is kept within ±5%.

6. The control method of the precision wire feeding control device for the laser-arc composite wire feeding additive manufacturing process according to claim 1, characterized in that, In step S6, the PID control algorithm is a discrete PID control algorithm. When the error between the contact force and the set force threshold exceeds ±5%, the PID controller is discretized on the IPC industrial computer, and the sampling interval is set to... The deviation between the set contact force and the actual wire feeding contact force obtained in step S5 each time is used as the input of the discrete PID controller, and the output of the discrete PID controller is used as the wire feeding speed adjustment amount. The output of the discrete PID controller is expressed by the following formula: in, It is a moment The amount of wire feeding speed control; This refers to the systematic error, which is the deviation between the set contact force and the actual wire feeding contact force. It is the accumulation of systematic errors; It is the rate of change of the systematic error; It is proportional gain; It is integral gain; It is the differential gain.

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