Laser Cladding Of Small Modulus Gear Repair Process Pilot Study

It has been researched that laser cladding is appied to the repairing of a close-toothed helical gear in this paper. Laser cladding for a close-toothed gear often meets such problems as the interference between the laser beam and the adjacent tooth flank, the crackings produced on the tooth flank coating,the caved tooth slot and the collapsed tooth tip. The experimental study shows that the smooth, non-cracking,non-caving,non-collapsing coating on the gear tooth can be obtained by the intelligent selection of the beam size, the beam positioning,the scanning technique,the technological parameters and the cladding procedure.For the cracking problem on the tooth flank coating, various coating methods are designed and experienced. Finally reseanable process method and parameter are confirmed. When cladding the tooth flank, the relative position between the laser spot and tooth flank is demanded severely, otherwise it is easy that the interference occurs, in the experiment the problem above is resolved through designing the rational relative position and selecting the appropriate spot size.For collapsing problem on the tooth tip coating, various experiment methods have been carried on. The method of depositing the powder in advance through the laser is proposed, that is, scanning in advance through the lower energy density laser enables the small partial powder to melt or to melt slightly, so that relying on the partial melting a large amounts of powder are felt and joined together into a mass attaching to the surface of tooth tip, then the formal cladding is carried on. Experiment indicates that the collapsing problem can be solved by the process above.During cladding the whole tooth and entire gear, the main problems faced with are the accumulation of heat and the uneven distribution of heat. In continuous scanning process, the thermal accumulation will cause the cladding pool preserve long time during the subsequent scanning, thereby causing the melt flowing, that is, the material is transferred. Uneven distribution of the heat will cause the entire gear uneven deformation. Through utilizing the reasonable scanning sequence and interval number of tooth, the problems of the thermal accumulation and distribution are solved.