Detection And Analysis Of Molten Pool Based On Computer Vision

Laser additive manufacturing technology is a special manufacturing technology that uses a high-energy laser to melt the surface of the substrate and the powder material together and then solidify,so that the surface of the substrate and the powder accumulate together.Compared with the traditional manufacturing technology,it has realized the "free manufacturing" of parts.It has some advantages such as good performance,no mold,short processing cycle,and is not limited by the material and structure of the parts.It has been widely used in aerospace,automotive,military industry,medical and many other fields.The main applications of laser additive manufacturing technology are coating processing,stacking forming,parts repair,etc.In recent years,the development of related technologies has made it applied to more extensive areas,but there are still shortcomings,especially in the aspect of laser additive manufacturing intellectualization and automation.In order to improve the intellectualization and automation of laser additive manufacturing,this paper uses computer vision-based methods to detect and extract the molten pool during the laser additive manufacturing process,and studies the change rule of the geometric characteristics of the molten pool when the technological parameters of laser additive manufacturing change,which lays a good foundation for the subsequent establishment of the intelligent control system of laser additive manufacturing.Therefore,this paper mainly completes the following contents:(1)Explain the research background and significance of this paper.This paper analyzes the current situation of laser additive manufacturing and the existing molten pool collection technology,detection technology and detection results,and finds out the shortcomings and potential improvements in the existing research.It is determined that the research content is molten pool detection and edge extraction based on the computer vision,and analyzes the rule of molten pool geometry characteristics changing with laser additive manufacturing process parameters.(2)Analyze the characteristics of the molten pool image,through research and experiment,select the camera,auxiliary light source,lens,filter and attenuation filters needed for molten pool collection,build appropriate molten pool collection device,and collect the molten pool image with high definition and good quality.(3)Propose the edge detection method based on improved object detection and semantic segmentation.By the use of improving convolution structure,improving loss function and adding multi-scale feature fusion network structure,the accuracy and speed of molten pool detection and edge extraction are greatly improved.(4)Obtain the area,length and height of the molten pool by using the improved algorithm,and study the influence of technological parameters such as laser power,powder feed rate and scan speed on the geometric characteristics of the molten pool.