Method for prefabricating poor fusion defects by controlling lmd process

A method for prefabricating a poor fusion defect by controlling a LMD process, comprising:

• obtaining a model, comprising a shaping zone and a defect prefabricated zone that has a preset defect;
• performing a layerwise slicing process on the model, wherein for each deposition layer of the defect prefabricated zone, the preset defect has a maximum dimension a0 in a perpendicular direction, which is perpendicular to a laser scan direction of the LMD process, wherein a0 takes a value within an interval range, the interval range is a variable range of a feature dimension of the poor fusion defect expected to be prefabricated, and the feature dimension is a maximum dimension of the poor fusion defect in the perpendicular direction;
• for the shaping zone, performing a shaping process under predetermined shaping process parameters of the LMD process;
• and
• for the defect prefabricated zone, controlling shaping process parameters as follows:
• for each deposition layer, when a0<D, with respect to the shaping zone, changing a scan pitch between shaping paths and a powder feed rate in the deposition layer, thereby prefabricating the poor fusion defect;
• and
• for each deposition layer, when a0≥D, with respect to the shaping zone, reducing energy input of laser in the deposition layer, thereby prefabricating the poor fusion defect;
• wherein D is a spot diameter of the laser in the deposition layer of the defect prefabricated zone.