Gear Tooth-shape Repairing By The Laser Additive And Subtractive Hybrid Manufacturing Technology Based On Image Detection Of Gear Tooth-profile

Gear drive is widely used in mechanical transmission structures,and it is also an important part of mechanical systems to carry kinetic loads.Along with continuous working status under load conditions and the impact of operating conditions,the gear is prone to tooth surface wear,tooth surface pitting and spalling,cracks and broken teeth,which not only affect the normal operation of the machine,but also cause serious accidents.For some special working occasions,the gear manufacturing cost is high,but the waste disposal of gears will cause a serious waste of resources.There are some traditional methods for repairing gears,such as adjusting transposition method,displacement processing method,overlay welding method and thermal spraying method.The new method uses laser additive manufacturing technology.Compared with traditional methods,laser additive manufacturing has the advantages of small heat-affected zone,excellent cladding performance,and easy repair of parts after repair.From the perspective of the integrity of the tooth shape,this paper strives to have a high shape and dimensional accuracy after the gear repairing.It uses the laser additive and subtractive hybrid manufacturing technology to clad the 316 L stainless steel powder to repair the worn gear.This paper focuses on the construction of the laser additive and subtractive hybrid manufacturing experimental platform based on tooth profile image detection.This system includes two parts: the tooth profile image acquisition hardware device and the tooth profile feature coordinate determination algorithm.The image acquisition hardware device aims to obtain the gear image as an input,and the algorithm corrects the distorted image through camera calibration,and then performs gray processing,image enhancement,and binarization on the obtained image to get the tooth profile feature pixel information,and establishes a mathematical model to convert the pixel information into the spatial coordinate information,and then uses the obtained spatial coordinate information to determine the repair state of the gear,as well as to determine the relative position between the milling cutter and the gear and between the laser beam and the gear during the repair process.The experiment shows that the tooth profile image detection system can meet the accuracy requirements of the gear repair process.The errors mainly come from the tooth profile feature coordinate determination algorithm,such as the noise existing in the image,threshold selection,etc.The accuracy could be improved by choosing a better filtering algorithm and multiple experiments to determine the appropriate threshold and so on.Based on the tooth profile image detection system,This paper successfully completed the gear repair experiment by using the laser additive and subtractive hybrid manufacturing technology,and finally achieved the result of repairing the gear at the level of tooth profile integrity,the relative error after repairing is 10%,which confirmed that the feasibility of the laser additive and subtractive hybrid manufacturing technology can be used to repair the complex shape parts.To a great extent,this technology saves resources and realizes the green manufacturing.