CN-117066652-B - Method and device for simultaneously observing cladding layer and molten pool in arc additive

Abstract

The invention relates to the technical field of additive manufacturing, in particular to a method and a device for simultaneously observing a cladding layer and a molten pool in arc additive. The device comprises a first CCD camera which is set to be in a low exposure and small gain mode, and a high-pass infrared filter which is added in front of the first CCD camera to effectively reduce the influence of arc light, and a second CCD camera which is set to be in a high exposure and large gain mode and images by means of arc light reflected by a cladding layer. According to the invention, based on a poisson fusion algorithm, the molten pool image shot by the first CCD camera and the cladding layer image shot by the second CCD camera are subjected to zone selection and splicing, so that the simultaneous observation of the cladding layer and the molten pool in the additive manufacturing process is realized. The invention has simple structure and can be widely applied to the field of arc material-increasing automation.

Inventors

• WANG KEHONG
• HUANG YONG
• Tan Xiaxin
• PENG YONG
• DUAN MENGWEI
• YANG DONGQING
• FAN JIKANG

Assignees

• 南京理工大学

Dates

Publication Date

20260512

Application Date

20230802

Claims (7)

1. 1.A method for observing a cladding layer and a molten pool in arc additive simultaneously is characterized by comprising the following steps: (1) The PC end sends out a shooting instruction, and the data acquisition card sends out a TTL level signal in response to the shooting instruction; (2) The method comprises the steps that a first CCD camera and a second CCD camera receive TTL high-level signals and shoot at the same time, an image obtained by the first CCD camera is a first original image, an image obtained by the second CCD camera is a second original image, the first CCD camera is used for imaging a molten pool area, and the second CCD camera is used for imaging a cladding layer area; (3) Calibrating the first CCD camera and the second CCD camera based on Zhang Zhengyou calibration methods by using a checkerboard or dot calibration plate to obtain internal parameters and external parameters of the first CCD camera and the second CCD camera; (4) Obtaining internal and external parameters of a camera to correct a first original image and a second original image respectively, wherein the corrected images are the first image and the second image; (5) Extracting the region of the ROI of the molten pool in the first image, which comprises the following steps: Step one, median filtering processing is carried out on a first image; Step two: based on Otsu algorithm, performing self-adaptive threshold segmentation on the image subjected to the median filtering treatment in the step one to obtain a binarization molten pool area image; thirdly, carrying out edge detection on the image subjected to binarization processing in the step based on a Canny algorithm; Step four, morphological expansion treatment is carried out, and in the finally treated image, a region surrounded by edges is a molten pool, and the region is extracted; (6) Based on a poisson fusion algorithm, fusing the ROI area in the first image with the second image; In the formula, The region is the ROI in the fused image; And (3) with Respectively, the images after fusion are in Pixel values inside and outside; Is that Is defined by a central region of the outer boundary of the mold; A gradient operator for the image; gradient vector fields of the second image and the ROI image, respectively; Is a constraint.
2. 2. A viewing device for a method for simultaneous viewing of a cladding layer and a molten pool in an arc additive as claimed in claim 1, characterized in that, The system comprises a data acquisition card; the data acquisition card is connected with the switch in parallel, and the two ends of the data acquisition card and the switch are respectively connected with the PC end and the double CCD cameras; The data acquisition card sends out high-low level signals TTL, and after receiving shooting instructions sent by the PC end, the data acquisition card sends out a TTL signal and simultaneously controls the double CCD cameras to shoot; a spectroscope and a high-pass filter are arranged in front of the first CCD camera; A total reflection mirror is arranged in front of the second CCD camera, so that all light transmitted through the spectroscope is captured by the second CCD camera and used for imaging the cladding layer.
3. 3. The device for observing the cladding layer and the molten pool simultaneously in arc additive according to claim 2, wherein the double CCD cameras are arranged in parallel at equal intervals and are positioned on the same horizontal plane.
4. 4. The device for simultaneously observing a cladding layer and a molten pool in an arc additive according to claim 2, wherein the first CCD camera has a first exposure time length and a first gain amplitude value, and the second CCD camera has a second exposure time length and a second gain amplitude value.
5. 5. The device of claim 4, wherein the first exposure time is less than the second exposure time and the first gain magnitude is less than the second gain magnitude during the additive process.
6. 6. The device for simultaneous observation of a cladding layer and a molten pool in an arc additive according to claim 2, wherein the first CCD camera is provided with a spectroscope having a transmittance/reflectance ratio of transmitted light/reflected light=1:1.
7. 7. The arc additive cladding layer and puddle simultaneous observation device of claim 2, wherein the high pass filter is a 850nm high pass filter.

Description

Method and device for simultaneously observing cladding layer and molten pool in arc additive Technical Field The invention relates to the technical field of material addition. More particularly relates to a method and a device for observing a cladding layer and a molten pool in arc additive. Background The additive manufacturing technology is a processing method for forming a workpiece by taking an electric arc as a heat source and taking a metal wire as a filling material, is an extremely important technology in the additive manufacturing, can provide more visual information for operators by monitoring a cladding layer and a molten pool of an additive area in the electric arc additive manufacturing process, is beneficial to the operators to judge the additive forming quality, can observe the deviation between an actual additive path and a preset path, further realizes the instant adjustment of additive process parameters and additive paths, and has important significance in the field of electric arc additive automation. However, because strong arc light is generated in the arc material increasing process, the conventional monocular camera has limited sensitivity, and can not image the molten pool area after the molten pool area is imaged. The method and the device for simultaneously observing the cladding layer and the molten pool in the arc additive are based on the binocular CCD camera, can realize simultaneous observation of the cladding layer and the molten pool, have important guiding function on real-time judgment of the additive quality and the additive path of an operator, and can be widely applied to the field of additive automation. The method for solving the problem of simultaneous observation of the cladding layer and the molten pool in the material adding process in the prior art comprises the steps of continuously or indirectly illuminating an material adding area through an external active light source, so that the brightness of the surrounding environment is greatly improved, the contrast ratio of arc light and the surrounding environment is weakened, the cladding layer and the molten pool are visualized, but because the arc light is too strong, the external light source needs to meet certain conditions, such as forming a certain included angle with the optical axis of a lens, the wavelength of the external light source needs to be selected according to different materials, and the like, the equipment of the illumination light source is complex, the use condition is greatly increased, and the automatic development of arc material adding is unfavorable. Disclosure of Invention In order to solve the technical problems, the invention provides a method and a device for simultaneously observing a cladding layer and a molten pool, wherein the method can realize dynamic observation of the molten pool and real-time observation of the cladding layer. In order to achieve the above purpose, the present invention provides a specific technical solution: The device comprises a PC end, a first CCD camera, a second CCD camera, a signal wire, a net wire, a spectroscope, a total reflection mirror, a switch, a data acquisition card and a 850nm high-pass infrared filter. The PC end is connected with the switch through a network cable and is connected with the data acquisition card through a signal line. The switch is connected with the first CCD camera and the second CCD camera through network cables respectively, and the data acquisition card is connected with the first CCD camera and the second CCD camera through signal lines respectively. Furthermore, the 850nm high-pass filter is additionally arranged in front of the first CCD camera, so that arc light interference can be greatly reduced. Further, a spectroscope with a 1:1 transmission/reflection ratio is placed in front of the first CCD camera, a total reflection mirror is placed in front of the second CCD camera, an included angle between the plane of the spectroscope and the plane of the lens of the first CCD camera is 45 degrees, and the spectroscope and the total reflection mirror are placed in parallel at equal intervals. Further, the first CCD camera and the second CCD camera are arranged in parallel at equal intervals and are in the same horizontal plane. The first CCD camera has the characteristics of low exposure and small gain, is beneficial to clear imaging of molten pool, and the second CCD camera has the characteristics of high exposure and large gain, and is beneficial to clear imaging of cladding layer. A method for observing a cladding layer and a molten pool in arc additive simultaneously specifically comprises the following steps: the PC end sends out shooting instructions, and the data acquisition card sends out TTL high-low level signals; And secondly, simultaneously triggering shooting by the first CCD camera and the second CCD camera in response to the high-level signal to obtain a first original image and a second original image. A