WO2022088296A1 - 一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统及其控制方法 - Google Patents

一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统及其控制方法 Download PDF

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WO2022088296A1
WO2022088296A1 PCT/CN2020/129781 CN2020129781W WO2022088296A1 WO 2022088296 A1 WO2022088296 A1 WO 2022088296A1 CN 2020129781 W CN2020129781 W CN 2020129781W WO 2022088296 A1 WO2022088296 A1 WO 2022088296A1
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cmt
droplet
stage
current
additive
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PCT/CN2020/129781
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English (en)
French (fr)
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彭勇
方辉
王克鸿
程远
李瑞峰
刘江华
郭振
王小满
张考
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南京联空智能增材研究院有限公司
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Publication of WO2022088296A1 publication Critical patent/WO2022088296A1/zh

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00Arc welding or cutting
    • B23K9/04Welding for other purposes than joining, e.g. built-up welding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B33ADDITIVE MANUFACTURING TECHNOLOGY
    • B33YADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00Processes of additive manufacturing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B33ADDITIVE MANUFACTURING TECHNOLOGY
    • B33YADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y30/00Apparatus for additive manufacturing; Details thereof or accessories therefor

Definitions

  • the invention relates to the field of metal arc additive manufacturing, in particular to a high-nitrogen steel arc additive system based on high-speed vision and electrical parameter synergistic sensing control and a control method thereof.
  • High nitrogen steel refers to ferritic steel with a nitrogen content of more than 0.08% or austenitic steel with a nitrogen content of more than 0.4%.
  • high nitrogen austenitic stainless steel uses nitrogen element as the main austenitizing element to replace the increasingly expensive nickel element, so as to achieve the purpose of reducing cost.
  • High nitrogen austenitic stainless steel has (1) lower cost; (2) high yield strength, tensile strength and ductility; (3) high strain hardening potential; (4) high fracture toughness; (5) resistance to formation of deformation Induced martensite; (6) good corrosion resistance; (7) a series of advantages such as low magnetic permeability, which make it suitable for large-scale structures, high-strength construction steel bars, mining, bulletproof armor, marine platforms and medical There are very broad application prospects in many fields such as equipment.
  • One purpose is to propose a high-nitrogen steel arc additive system based on high-speed vision and electrical parameter synergistic sensing control, so as to reduce the splash caused by the explosion due to excessive droplets during the high-nitrogen steel arc additive process, and improve the additive process. Process stability and additive part yield.
  • a further object is to propose a control method based on the above system.
  • a high-nitrogen steel arc additive system based on high-speed vision and electrical parameter cooperative sensing control including an additive robot for controlling the motion of the welding torch; a CMT power source for supplying welding current; and for melting wire for additive work
  • the CMT welding gun the laser used to generate the light source for the high-speed camera to photograph the droplet transition;
  • a high-speed camera for photographing the transition state of the droplet during the additive process; an electrical signal acquisition unit for collecting the current and voltage waveforms during the additive process; The size and state of the droplet control the upper computer controller of the welding current and voltage waveform of the CMT power supply.
  • the CMT power supply generates a composite current and voltage waveform of CMT+P, and the wavelength of the laser generated by the laser is 810 nm; the lens of the high-speed camera is provided with matching with the laser and used for filtering 810nm filter for arc light, the high-speed camera shoots at a shooting frequency of 5000Hz.
  • the electrical signal acquisition unit is connected to the high-speed camera.
  • a 3V external pulse trigger signal is given to the high-speed camera to realize synchronous acquisition, and the acquisition frequency of the electrical signal acquisition unit is 5000 Hz.
  • the host computer controller receives the droplet transition image collected from the high-speed camera, and receives the current and voltage waveforms uploaded from the electrical signal acquisition unit, and extracts the droplet size and transition characteristics in real time , compare the droplet size with the preset threshold, and feed it back to the CMT power supply for real-time adjustment of the output current and voltage waveforms.
  • the diameter is the feedback quantity, and the pulse peak current time and the pulse peak current size are used as the control quantities.
  • the high-nitrogen steel arc additive control method based on high-speed vision and electrical parameter cooperative sensing control includes the following steps:
  • the droplet remains unchanged or grows within a predetermined range. No splash is generated; in the pulse peak stage, the droplet grows rapidly to a predetermined size and then splashes. Therefore, the image at the pulse peak stage is firstly intercepted frame by frame; then the intercepted images are segmented by threshold using Matlab batches, because the liquid droplet There are different grayscale values between itself and the surrounding area, set the critical grayscale value to T, set the pixel grayscale value to 255 when the image is higher than the T value, and set the pixel grayscale value to 0 when it is lower than the T value.
  • the upper computer controller receives the current and voltage waveforms uploaded by the electrical signal acquisition unit;
  • the host computer controller compares the extracted droplet size with the preset threshold in real time, and feeds back to the CMT power supply to adjust the output current and voltage waveform in real time.
  • the real-time feedback adjustment process of the output current and voltage waveform of the CMT power supply is:
  • the additive starts, the molten droplets are formed and grown in the pulse peak stage, accompanied by a predetermined degree of explosion, and then transition into the molten pool in the CMT stage;
  • the ratio of the number of CMT to P in the CMT+P current waveform is 1:1, that is, the CMT stage starts after the end of a pulse stage, and the droplets formed in the pulse stage are fed through the welding wire of the CMT stage. and the retraction movement to complete the transition.
  • the threshold D min is a minimum value to ensure that the welding seam is well formed
  • the threshold value D max is a maximum value to ensure that the droplet is stable and does not produce violent explosions.
  • the time adjustment range of the pulse peak current is 1.8ms ⁇ 4.6ms, and the size adjustment range of the pulse peak current is 150A ⁇ 300A.
  • the present invention performs additive work on a high-nitrogen steel arc additive system based on high-speed vision and electrical parameter collaborative sensing control.
  • the ratio of the number of pulses to the number of CMTs is preset to be 1:1, so that the The droplet completes the transition in the CMT stage; through the host computer controller, the diameter of the droplet formed in the pulse stage is used as the feedback quantity, and the pulse peak current time and the pulse peak current size are used as the control quantities to ensure that each deposited metal is well formed.
  • the splash caused by the explosion caused by the large droplet is reduced, the stability of the high nitrogen steel arc additive is improved, and the workload of splash cleaning is reduced.
  • FIG. 1 is a schematic diagram of the arc additive system of the present invention.
  • FIG. 2 is a flow chart of feedback of the CMT power supply output current waveform control signal according to the present invention.
  • FIG. 3 is a schematic diagram corresponding to a current-voltage waveform control curve and a droplet transition process according to a specific embodiment of the present invention.
  • FIG. 4 is a physical diagram of the additive sample of Example 1 obtained by using the system and control method of the present invention.
  • the reference numerals in the figure are: additive robot 1 , CMT power source 2 , CMT welding torch 3 , laser 4 , high-speed camera 5 , electrical signal acquisition unit 6 , and host computer controller 7 .
  • the present invention is a high-nitrogen steel arc additive system based on high-speed vision and electrical parameter collaborative sensing control, which includes an additive robot, a CMT power source, a CMT welding torch, a laser, a high-speed camera, and an electrical signal acquisition unit. , the host computer controller.
  • the additive robot is used to control the motion of the welding torch; the CMT power source is used to provide welding current; the CMT welding torch is used to melt the wire material for additive work; the laser is used to generate a high-speed camera to capture the light source when the droplet transitions ; the high-speed camera is used to photograph the transition state of the droplet during the additive process; the electrical signal acquisition unit is used to collect the current and voltage waveforms during the additive process; the host computer controller is used to receive the droplet transition image collected during the additive process and current and voltage waveforms, and control the welding current and voltage waveforms of the CMT power supply according to the size and state of the droplet.
  • the CMT power supply generates a composite current and voltage waveform of CMT+P.
  • the laser wavelength generated by the laser is 810 nm.
  • An 810nm filter matched with the laser light source is installed in front of the high-speed camera lens for filtering arc light, and the shooting frequency is 5000Hz.
  • the electrical signal acquisition unit is connected to the high-speed camera. When the electrical signal acquisition unit starts to acquire, a 3V external pulse trigger signal is given to the high-speed camera to realize synchronous acquisition.
  • the acquisition frequency of the electrical signal acquisition unit is 5000 Hz.
  • the present invention further proposes an arc additive control method.
  • the high-speed camera and the laser are focused on the end of the welding wire to collect the droplet transition image and upload the image to the host computer controller.
  • the host computer controller receives The current and voltage waveforms uploaded to the electrical signal acquisition unit, the host computer controller compares the extracted droplet size with the preset threshold in real time, and feeds back to the CMT power supply for real-time adjustment of the output current and voltage waveforms.
  • the high-speed camera and laser focus on the end of the welding wire to collect the droplet transition image and display the image on the host computer controller in real time through the supporting software.
  • the droplet remains unchanged or grows slightly , basically no spatter will be generated, but in the pulse peak stage, the droplets rapidly grow to a predetermined size and then generate a large amount of spatter. Therefore, the images in the pulse peak stage are first captured frame by frame, and then the captured images are batched by Matlab.
  • Threshold segmentation because the liquid drop itself has different grayscale values from its surroundings, set the critical grayscale value to T, set the pixel grayscale value to 255 when the image is higher than the T value, and set the pixel grayscale value to the pixel when it is lower than the T value.
  • the upper computer controller receives the current and voltage waveforms uploaded by the electrical signal acquisition unit;
  • the host computer controller compares the extracted droplet size with the preset threshold in real time, and feeds back to the CMT power supply for real-time adjustment of the output current and voltage waveform;
  • the real-time feedback adjustment process of the output current and voltage waveform of the CMT power supply is as follows:
  • the pulse peak current time is t p
  • the pulse peak current size is I p ;
  • the ratio of the number of CMT to P in the CMT+P current waveform is 1:1, that is, the CMT stage starts after the end of a pulse stage, and the droplets formed in the pulse stage are fed and returned through the welding wire of the CMT stage. Pump movement to complete the transition.
  • the threshold value D min is a minimum value to ensure that the welding seam is well formed
  • the threshold value D max is a maximum value to ensure that the droplet is stable and does not produce violent explosions.
  • the time adjustment range of the pulse peak current is 1.8ms ⁇ 4.6ms, and the size adjustment range of the pulse peak current is 150A ⁇ 300A.
  • the preset welding waveform is CMT+P and the number ratio is 1:1, the preset pulse peak current is 300A, and the pulse peak current time 2.0ms;
  • the wire feeding speed is 5m/min
  • the welding speed is 4mm/s
  • the shielding gas is Ar1.5% O2 5% N2 ternary shielding gas of 25L/min
  • the interlayer temperature is controlled at 100°C;
  • the welding gun moves to the arc starting point according to the set program, and the welding robot moves in a straight line in the Y-axis direction according to the preset trajectory. Mechanical grinding of the weld at the set safety point;
  • step 8 until the additive work of the straight wall parts is completed

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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
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Abstract

一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统及其控制方法,系统包括增材机器人(1)、CMT电源(2)、CMT焊枪(3)、激光器(4)、高速相机(5)、电信号采集单元(6)、上位机控制器(7);高速相机(5)与激光器(4)聚焦于焊丝末端用于采集熔滴过渡图像,上位机控制器(7)用于接收高速相机(5)采集到的熔滴图像和电信号采集单元(6)采集到的电流电压波形,提取图像中的熔滴尺寸;电弧增材的方法为:使得脉冲阶段形成的熔滴在CMT阶段完成过渡,接着通过上位机控制器(7)以脉冲阶段形成的熔滴的直径为反馈量,以脉冲峰值电流时间和脉冲峰值电流大小为控制量,在保证每一道熔敷金属成型良好的基础上减小因熔滴过大进而爆炸产生的飞溅,提高了高氮钢焊丝电弧增材的稳定性,减少了飞溅清理工作量。

Description

一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统及其控制方法 技术领域
本发明涉及金属电弧增材制造领域,具体涉及一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统及其控制方法。
背景技术
高氮钢是指氮含量达到0.08%以上的铁素体钢或者氮含量达到0.4%以上的奥氏体钢。其中,高氮奥氏体不锈钢使用氮元素作为主要的奥氏体化元素来替代日益昂贵的镍元素,从而达到降低成本的目的。高氮奥氏体不锈钢具有(1)成本较低;(2)屈服强度、拉伸强度高和延展性好;(3)应变硬化潜力高;(4)断裂韧性高;(5)阻止形成变形诱导马氏体;(6)很好的耐腐蚀性能;(7)低磁导率等一系列优点,这些优点使其在大型结构、高强度建筑钢筋、矿山开采、防弹装甲、海洋平台和医疗器械等多领域都有十分广阔的应用前景。
高氮钢焊丝由于其本身的成分特点(高氮、高锰),在熔化极电弧增材工艺条件下,很容易就形成大量飞溅,极大地增加了清理工作量和缺陷产生的概率。通过研究与观察发现熔滴在形成与长大阶段便发生剧烈爆炸,爆炸导致大熔滴被分散成无数细小的液滴,此时一部分小液滴过渡到熔池中成为熔敷金属,而另一部分未进入熔池的微细液滴则在爆炸力作用下向四周飞散出去成为飞溅,并且在重力作用下梯度分布在熔池四周。这些飞溅在空气中被氧化后落在构件表面,在移动电弧热源的加热作用下重新熔化进入层间,进而导致增材件层间产生裂纹。
因此,减小高氮钢电弧增材过程中因为熔滴过大而爆炸产生的飞溅,提高增材过程的稳定性和增材件的合格率是高氮钢焊丝电弧增材亟待解决的问题。
技术问题
一个目的是提出一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,以减小高氮钢电弧增材过程中因为熔滴过大而爆炸产生的飞溅,提高增材过程的稳定性和增材件的合格率。进一步目的是提出一种基于上述系统的控制方法。
技术解决方案
一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,包括用于控制焊枪运动的增材机器人;用于提供焊接电流的CMT电源;用于熔化丝材进行增材工作的CMT焊枪;用于产生高速相机拍摄熔滴过渡时的光源的激光器;
用于拍摄增材时熔滴过渡状态的高速相机;用于采集增材时电流电压波形的电信号采集单元;以及用于接收增材时采集到的熔滴过渡图像和电流电压波形,并根据熔滴大小和状态控制CMT电源的焊接电流电压波形的上位机控制器。
在进一步的实施例中,所述CMT电源产生CMT+P的复合电流电压波形,所述激光器产生的激光波长为810nm;所述高速相机的镜头前设有与所述激光器匹配、且用于过滤弧光的810nm滤光片,所述高速相机以5000Hz的拍摄频率拍摄。
在进一步的实施例中,所述电信号采集单元与所述高速相机相连,电信号采集单元开始采集时给高速相机一个3V外部脉冲触发信号实现同步采集,电信号采集单元采集频率为5000Hz。
在进一步的实施例中,所述上位机控制器接收来自所述高速相机采集到的熔滴过渡图像,并接收来自所述电信号采集单元上传的电流电压波形,实时提取熔滴大小和过渡特性,将熔滴大小与预设阈值进行对比,同时反馈给CMT电源进行输出电流电压波形的实时调节。
一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,通过控制使得脉冲阶段形成的熔滴在CMT阶段完成过渡,通过上位机控制器以脉冲阶段形成的熔滴的直径为反馈量,以脉冲峰值电流时间和脉冲峰值电流大小为控制量,在保证每一道熔敷金属成型良好的基础上减小因熔滴过大进而爆炸产生的飞溅。
在进一步的实施例中,基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法包括如下步骤:
S1、高速相机与激光器聚焦于焊丝末端用于采集熔滴过渡图像并将图像显示在上位机控制器上,在脉冲基值阶段和CMT阶段,熔滴维持不变或在预定范围内长大,不产生飞溅;在脉冲峰值阶段,熔滴迅速长大至预定大小后产生飞溅,因此首先对脉冲峰值阶段的图像进行逐帧截取;接着利用Matlab批量对截取的图像进行阈值分割,因为液态熔滴本身跟周围存在不同的灰度值,设置临界灰度值为T,图像中高于T值时将此像素灰度值设为255,低于T值时将此像素灰度值设为0,得到二值图像;然后进行数字形态处理,对从熔滴中分离出来的飞溅和细小熔滴等干扰信息进行排除;最后利用Matlab批量计算二值图像的像素面积并转换成对应的熔滴直径,相互之间比较得到脉冲峰值阶段中熔滴能长大的最大直径D;
S2、上位机控制器接收到电信号采集单元上传的电流电压波形;
S3、上位机控制器实时将提取的熔滴大小与预设阈值进行对比,同时反馈给CMT电源进行输出电流电压波形的实时调节。
在进一步的实施例中,所述CMT电源输出电流电压波形的实时反馈调节过程为:
S301、增材开始前,预设CMT+P电流波形的特征参数,脉冲峰值电流时间为t p,脉冲峰值电流大小为I p
S302、增材开始,熔滴在脉冲峰值阶段形成并长大,并伴随着预定程度的爆炸,接着在CMT阶段过渡到熔池中;
S303、对脉冲峰值阶段形成的熔滴最大直径D与预设阈值进行比较,当D小于D min时,反馈控制信号提高脉冲峰值电流时间至(D min/D)t p或提高脉冲峰值电流大小至(D min/D)I p,当D大于D max时,反馈控制信号降低脉冲峰值电流时间至(D max/D)t p或降低脉冲峰值电流大小至(D max/D)I p
在进一步的实施例中,所述CMT+P电流波形中CMT与P的个数比为1:1,即一个脉冲阶段结束后开始CMT阶段,脉冲阶段形成的熔滴通过CMT阶段的焊丝送进和回抽运动完成过渡。
在进一步的实施例中,所述阈值D min为保证焊缝成型良好的最小值,所述阈值D max为保证熔滴稳定不产生剧烈爆炸的最大值。
在进一步的实施例中,所述脉冲峰值电流时间调节范围为1.8ms~4.6ms,所述脉冲峰值电流大小调节范围为150A~300A。
有益效果
本发明在一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统上进行增材工作,首先预设脉冲个数与CMT个数比为1:1,使得脉冲阶段形成的熔滴在CMT阶段完成过渡;通过上位机控制器以脉冲阶段形成的熔滴的直径为反馈量,以脉冲峰值电流时间和脉冲峰值电流大小为控制量,在保证每一道熔敷金属成型良好的基础上减小因熔滴过大进而爆炸产生的飞溅,提高了高氮钢电弧增材的稳定性,减少了飞溅清理工作量。
附图说明
图1为本发明电弧增材系统的示意图。
图2为本发明CMT电源输出电流波形控制信号反馈流程图。
图3为本发明的一个具体实施例的电流电压波形控制曲线与熔滴过渡过程对应示意图。
图4为利用本发明系统和控制方法所得实施例1的增材样件实物图。
图中各附图标记为:增材机器人1,CMT电源2,CMT焊枪3,激光器4,高速相机5,电信号采集单元6,上位机控制器7。
本发明的实施方式
在下文的描述中,给出了大量具体的细节以便提供对本实用新型更为彻底的理解。然而,对于本领域技术人员而言显而易见的是,本实用新型可以无需一个或多个这些细节而得以实施。在其他的例子中,为了避免与本实用新型发生混淆,对于本领域公知的一些技术特征未进行描述。
申请人认为,高氮钢焊丝由于其本身的成分特点(高氮、高锰),在熔化极电弧增材工艺条件下,很容易就形成大量飞溅,极大地增加了清理工作量和缺陷产生的概率。通过研究与观察发现熔滴在形成与长大阶段便发生剧烈爆炸,爆炸导致大熔滴被分散成无数细小的液滴,此时一部分小液滴过渡到熔池中成为熔敷金属,而另一部分未进入熔池的微细液滴则在爆炸力作用下向四周飞散出去成为飞溅,并且在重力作用下梯度分布在熔池四周。这些飞溅在空气中被氧化后落在构件表面,在移动电弧热源的加热作用下重新熔化进入层间,进而导致增材件层间产生裂纹。
因此,如何减小高氮钢电弧增材过程中因为熔滴过大而爆炸产生的飞溅,以提高增材过程的稳定性和增材件的合格率是高氮钢焊丝电弧增材亟待解决的问题,也是本发明要解决的实际问题。
如图1所示,本发明一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,它包含增材机器人、CMT电源、CMT焊枪、激光器、高速相机、电信号采集单元、上位机控制器。所述增材机器人用于控制焊枪运动;所述CMT电源用于提供焊接电流;所述CMT焊枪用于熔化丝材进行增材工作;所述激光器用于产生高速相机拍摄熔滴过渡时的光源;所述高速相机用于拍摄增材时熔滴过渡状态;所述电信号采集单元用于采集增材时电流电压波形;所述上位机控制器用于接收增材时采集到的熔滴过渡图像和电流电压波形,并根据熔滴大小和状态控制CMT电源的焊接电流电压波形。
作为一个优选方案,所述CMT电源产生CMT+P的复合电流电压波形。所述激光器产生的激光波长为810nm。所述高速相机镜头前装有跟激光光源配套的810nm滤光片用于过滤弧光,拍摄频率为5000Hz。所述电信号采集单元跟高速相机相连,电信号采集单元开始采集时给高速相机一个3V的外部脉冲触发信号实现同步采集,电信号采集单元采集频率为5000Hz。
基于上述电弧增材系统,本发明进一步提出一种电弧增材控制方法,高速相机与激光器聚焦于焊丝末端用于采集熔滴过渡图像并将图像上传至上位机控制器,同时上位机控制器接收到电信号采集单元上传的电流电压波形,上位机控制器实时将提取的熔滴大小与预设阈值进行对比,同时反馈给CMT电源进行输出电流电压波形的实时调节。
具体步骤如下:
S1、高速相机与激光器聚焦于焊丝末端用于采集熔滴过渡图像并将图像通过配套软件实时显示在上位机控制器上,在脉冲基值阶段和CMT阶段,熔滴维持不变或少许长大,基本不会产生飞溅,而在脉冲峰值阶段,熔滴迅速长大至预定大小后产生大量飞溅,因此首先对脉冲峰值阶段的图像进行逐帧截取,接着利用Matlab批量对截取的图像进行阈值分割,因为液态熔滴本身跟周围存在不同的灰度值,设置临界灰度值为T,图像中高于T值时将此像素灰度值设为255,低于T值时将此像素灰度值设为0,得到二值图像,然后进行数字形态处理,对从熔滴中分离出来的飞溅和细小熔滴等干扰信息进行排除,最后利用Matlab批量计算二值图像的像素面积并转换成对应的熔滴直径,相互之间比较得到脉冲峰值阶段中熔滴能长大的最大直径D;
S2、上位机控制器接收到电信号采集单元上传的电流电压波形;
S3、上位机控制器实时将提取的熔滴大小与预设阈值进行对比,同时反馈给CMT电源进行输出电流电压波形的实时调节;
其中,CMT电源输出电流电压波形的实时反馈调节过程为:
1)增材开始前,预设CMT+P电流波形的特征参数,脉冲峰值电流时间为t p,脉冲峰值电流大小为I p
2)增材开始,熔滴在脉冲峰值阶段形成并长大,并伴随着预定程度的爆炸,接着在CMT阶段过渡到熔池中;
3)对脉冲峰值阶段形成的熔滴最大直径D与预设阈值进行比较,当D小于D min时,反馈控制信号提高脉冲峰值电流时间至(D min/D)t p或提高脉冲峰值电流大小至(D min/D)I p,当D大于D max时,反馈控制信号降低脉冲峰值电流时间至(D max/D)t p或降低脉冲峰值电流大小至(D max/D)I p
作为一个优选方案,所述CMT+P电流波形中CMT与P的个数比为1:1,即一个脉冲阶段结束后开始CMT阶段,脉冲阶段形成的熔滴通过CMT阶段的焊丝送进和回抽运动完成过渡。所述阈值D min为保证焊缝成型良好的最小值,所述阈值D max为保证熔滴稳定不产生剧烈爆炸的最大值。所述脉冲峰值电流时间调节范围为1.8ms~4.6ms,所述脉冲峰值电流大小调节范围为150A~300A。
实施例1
以牌号HNS6T2、直径1mm的高氮钢焊丝,400mm*200mm*10mm的316L不锈钢基板增材直壁体为例。具体步骤如下:
1、在软件中生成直壁体增材程序并导入机器人示教器中;
2、钢丝刷打磨316L不锈钢基板,去除氧化物等杂物,打开保护气、焊接电源,预设焊接波形为CMT+P且个数比1:1,预设脉冲峰值电流300A,脉冲峰值电流时间2.0ms;
3、打开激光器,设置激光频率20000Hz;
4、打开高速相机,设置采集频率5000Hz;
5、打开电信号采集盒,设置采集频率5000Hz;
6、确定增材工艺参数,本实施例送丝速度5m/min,焊接速度4mm/s,保护气为25L/min的Ar1.5%O 25%N 2三元保护气,层间温度控制在100℃;
7、调节喷嘴距离基板15mm的位置为起弧点;
8、启动焊接机器人,焊枪按设置好的程序移至起弧点进行起弧,焊接机器人按预设轨迹在Y轴方向沿直线运动,完成一道增材后在焊缝末端息弧并移至预设好的安全点对焊缝进行机械打磨;
9、焊缝表面冷却到100℃后焊枪移至上一道焊缝熄弧点上1.8mm位置处进行起弧,运动到上一道焊缝起弧点位置上方1.8mm处时熄弧,焊枪移至安全点对焊缝进行打磨;
10、重复步骤8,直至完成直壁体件的增材工作;
11、焊枪移至初始位置,关闭保护气、焊接电源、机器人控制柜、激光器电源、高速相机电源、电信号采集盒电源,待增材件完全冷却后从工作台上卸下。
如上所述,尽管参照特定的优选实施例已经表示和表述了本发明,但其不得解释为对本发明自身的限制。在不脱离所附权利要求定义的本发明的精神和范围前提下,可对其在形式上和细节上做出各种变化。

Claims (10)

  1. 一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,其特征在于,包括:
    用于控制焊枪运动的增材机器人;
    用于提供焊接电流的CMT电源;
    用于熔化丝材进行增材工作的CMT焊枪;
    用于产生高速相机拍摄熔滴过渡时的光源的激光器;
    用于拍摄增材时熔滴过渡状态的高速相机;
    用于采集增材时电流电压波形的电信号采集单元;
    用于接收增材时采集到的熔滴过渡图像和电流电压波形,并根据熔滴大小和状态控制CMT电源的焊接电流电压波形的上位机控制器。
  2. 根据权利要求1所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,其特征在于,所述CMT电源产生CMT+P的复合电流电压波形,所述高速相机的镜头前设有与所述激光器匹配、且用于过滤弧光的滤光片,所述高速相机以预定拍摄频率拍摄。
  3. 根据权利要求1所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,其特征在于,所述电信号采集单元与所述高速相机相连,电信号采集单元开始采集时给高速相机一个外部脉冲触发信号实现同步采集。
  4. 根据权利要求1所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材系统,其特征在于,所述上位机控制器接收来自所述高速相机采集到的熔滴过渡图像,并接收来自所述电信号采集单元上传的电流电压波形,实时提取熔滴大小和过渡特性,将熔滴大小与预设阈值进行对比,同时反馈给CMT电源进行输出电流电压波形的实时调节。
  5. 一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,其特征在于,通过控制使得脉冲阶段形成的熔滴在CMT阶段完成过渡,通过上位机控制器以脉冲阶段形成的熔滴的直径为反馈量,以脉冲峰值电流时间和脉冲峰值电流大小为控制量,在保证每一道熔敷金属成型良好的基础上减小因熔滴过大进而爆炸产生的飞溅。
  6. 根据权利要求5所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,其特征在于,包括如下步骤:
    S1、高速相机与激光器聚焦于焊丝末端用于采集熔滴过渡图像并将图像显示在上位机控制器上,在脉冲基值阶段和CMT阶段,熔滴维持不变或在预定范围内长大,不产生飞溅;在脉冲峰值阶段,熔滴迅速长大至预定大小后产生飞溅,因此首先对脉冲峰值阶段的图像进行逐帧截取;
    接着利用Matlab批量对截取的图像进行阈值分割,因为液态熔滴本身跟周围存在不同的灰度值,设置临界灰度值为T,图像中高于T值时将此像素灰度值设为255,低于T值时将此像素灰度值设为0,得到二值图像;
    然后进行数字形态处理,对从熔滴中分离出来的飞溅和细小熔滴等干扰信息进行排除;
    最后利用Matlab批量计算二值图像的像素面积并转换成对应的熔滴直径,相互之间比较得到脉冲峰值阶段中熔滴能长大的最大直径D;
    S2、上位机控制器接收到电信号采集单元上传的电流电压波形;
    S3、上位机控制器实时将提取的熔滴大小与预设阈值进行对比,同时反馈给CMT电源进行输出电流电压波形的实时调节。
  7. 根据权利要求5所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,其特征在于,S3中所述CMT电源输出电流电压波形的实时反馈调节过程进一步包括:
    S301、增材开始前,预设CMT+P电流波形的特征参数,脉冲峰值电流时间为t p,脉冲峰值电流大小为I p
    S302、增材开始,熔滴在脉冲峰值阶段形成并长大,并伴随着预定程度的爆炸,接着在CMT阶段过渡到熔池中;
    S303、对脉冲峰值阶段形成的熔滴最大直径D与预设阈值进行比较,当D小于D min时,反馈控制信号提高脉冲峰值电流时间至(D min/D)t p或提高脉冲峰值电流大小至(D min/D)I p,当D大于D max时,反馈控制信号降低脉冲峰值电流时间至(D max/D)t p或降低脉冲峰值电流大小至(D max/D)I p
  8. 根据权利要求7所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,其特征在于,所述CMT+P电流波形中CMT与P的个数比为1:1,即一个脉冲阶段结束后开始CMT阶段,脉冲阶段形成的熔滴通过CMT阶段的焊丝送进和回抽运动完成过渡。
  9. 根据权利要求7所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,其特征在于,所述阈值D min为保证焊缝成型良好的最小值,所述阈值D max为保证熔滴稳定不产生剧烈爆炸的最大值。
  10. 根据权利要求7所述的一种基于高速视觉和电参数协同传感控制的高氮钢电弧增材控制方法,其特征在于,所述脉冲峰值电流时间调节范围为1.8ms~4.6ms,所述脉冲峰值电流大小调节范围为150A~300A。
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