Research Of High Power Laser Cladding Rapid Prototyping Technology

This research adopts Fe-based and Ni-based alloy powder based on the 45-steel plate for laser cladding rapid prototyping experiments. Improved powder sender and powder head, analyzed the material factors (material index, powder grain size) and laser parameters (laser power, sweeping velocity, spot diameter, overlap ratio between sweeping lines, powder sending amount) that effect the quality of prototyping samples. Investigated the prototyping technology characteristics, such as heels that formed at the beginning and the end of sweeping lines, powder splash, spheroidization. Analyzed the forming reason of heel, and established the equation to avoid the appearance of heel. By keeping powder dry and reducing the impurity of powder can lower the powder splash. If laser molten pool can't form full convection, it will cause discontinuous balls on the surface of sweeping line. In the case of keeping other parameters constant, increasing laser power can avoid ball. The relative position between powder sending landing and spot can effect the quality of ring sample, if powder locates inside of spot, the outside wall of ring sample is smooth; otherwise, the inside wall is smooth.Adopted suitable scanning method based on the comparison and analysis of different slicing scanning strategies. Single track scanning is used for manufacturing straight line and thin wall samples. Multiple tracks overlap scanning is used for thick wall samples or complex geometry and non-uniform wall samples. Have successfully manufactured some samples, such as roller sample, rectangular solid sample, pentagram sample, regular sample, pyramid sample, @-character sample; all samples have definite geometric shape and precision, the tallest height of sample is 105mm.By micro measurement and analysis, the study found that the combination between Fe-based sample , Ni-based sample and base plate is full metallurgical bonding; The microstructure of single track line is continuous and tight, with no gas cavity and crack; overlap of multiple scanning lines is full metallurgical bonding; all...