On-line Monitoring And Control Based On CCD Laser Cladding Forming Process

Laser cladding rapid prototyping manufacturing technology is a new technique whichdevelops on the basis of Laser cladding technology and rapid prototyping technology .InLaser cladding rapid forming process , Laser cladding layer height is decided by laserparameter ,the processing technology , the powder material factors and so on. This articlebased on CCD achieves a realization of a real - time monitoring of manufacturing processand the feedback control by using cladding height information ,to ensure the smoothconduct of the cladding process and improve the quality of forming processing .Cladding forming test uses this group of patent technology -- light coaxial powderfeeding system. The system ,in the Single-channel cladding, showed many advantages suchas the powder coupling stability, the isotropic quality, high powder utilization ratio , goodquality of the melting layer surface . But the experiments found that ,in the process of high- piled up, the distance between laser molten pool center to the powder outlet is on theincrease by the number of cladding layer, which will cause the effect of light powdercoupling get worse, even directly lead to failure. This article uses the characteristics of thedouble– beam, which is made up of the spot forming by molten pool and the reflectionspot by Laser surface . Using the centroid distance of two spot as the height controllingquantity to feedback control the mobile incremental of laser head Z .This study ,with a 500000-pixel color CCD, makes the real - time monitoring for twospots , uses image acquisition card for image acquisition and the digital image processingtechnology to analyze and calculate collecting pictures for the centroid distance changes inthe value of two spot.The whole image processing software develops basing on VC++ platform. Usingimage gray processing, Gaussian smoothing, binary threshold segmentation, area centroidcalculation, and the centroid coordinate distance calculation in digital image processing todeal with pictures by CCD. Through the validation of the accumulation Experiment of high- rise complex parts, the software can reflect real - time distance between laser head to bath center (centroid distance of the two spot), then we can make a corresponding adjustmentto the mobile increment of laser head Z, providing new ways for on - line monitoring ofLaser cladding rapid prototyping manufacturing technology .