Laser Direct Manufacturing And Manufacturing Technology Cam Research

Laser direct manufacturing and re-manufacturing is an advanced manufacturing technology which just rises and has been developed in the last few years. This technology is actually an additive-layered manufacturing technology which applys coaxial powder feeding laser cladding technology according to rapid protyping principle. It is a new advanced manufacturing technology which integrates optics, mechanics, electrics, computer, automation and material science. Therefore, there are many problems need to be studied or solved whether in basic theory, processing technology, equipment developing or industry application. In this paper, the development status of laser direct manufacturing and re-manufacturing was first summarized comprehensively and then the hardware system developed by ourselves were introduced. The studying work mostly includes the research or designing of coaxial nozzle, studing or developing of CAD/CAM prototype system in laser manufacturing and processing practice.Coaxial powder feeding nozzle is one of the key components in laser direct manufacturing and re-manufacturing. The powder parameters from nozzle directly influenced the part precision and face quality and hence it is necessary to study the powder flow movement for coaxial nozzle designing and process optimizing in laser manufacturing. By analyzing the powder feeding technology, the coaxial nozzle was designed to have two coaxial nozzle tips. According to the double-fluid model in gas-particle two-phase theory, the basic governing equations of powder flow out of coaxial nozzle tips was established to simulate the powder flow in coaxial powder feeding with carrying gas. The concentration distributing of powder flow and powder parameters (focus distance to nozzle exit and focus radius of of powder flow) varying are simulated and analyzed. The effect of gas flux and feeding powder rate upon powder parameters was studied. Comparing the result of computer simulation with one of measurement by DPIV(Digital Particle Image Velocimetry), it is shown that a good agreement between theoretical and experimental data can be obtained. Meanwhile, a series of coaxial nozzles have been designed and manufactured.CAD/CAM application software system is used for for parts body modeling and converting three_ dimensional model into NC code to control machine forming movement. It is the premise or base of laser direct manufacturing and re-manufacturing. It is the important factor influencing process velocity, accuracy and efficiency. The software system running procedure was analysed according to principle of laser direct manufacturing and re-manufacturing. The whole system consists of 3D solid modeling module(including 3D reverse engineering), tool path generating module, tool path simulating module, process parameters setting and process data-base module, NC code generating module and data transmitting module. Further developing technology of general CAD software was studied and the CAD/CAM system frame has been laid out.By studying the data structure of CAD solid model and the method for obtaining geometric and topological information from CAD model, a direct slicing approach is proposed in which the surface-surface intersection function of Application Programming Interface (API) functions was called to get the section contours of model surface and slicing plane from CAD solid models. A series of algorithms such as extracting the information of section contours, sorting and discretizing section contours, generating raster filling path have been put forward. The direct slicing program based on above algorithms has been developed in which process parameters including laser power, scanning velocity, slicing thickness, cladding width or discrete tolerance can be set, solid model can be sliced along different directions and tool path for contouring or filling be generated. The slices data are saved in special file in which lines, arcs and circles are used to describe the section contours. The direct slicing result was simulated in software. Part was fabricated with application of direct slicing software. Comparing the part fabricated based on direct slicing format with part based on stereolithography (STL) format ,it is shown that the accuracy and surface finish of direct slicing part was better than STL indirect slicing.For the sake of improving manufacturing accuracy or reducing step effect, an adaptive direct slicing method complete with the algorithm for calculating the thickness of layers is proposed. By adopting the normal vector judge principle, it was programmed based on the commercial CAD software package. The method was shown to be fast and accurate in comparison with direct slicing.Five-axis laser machining system is used to build a part having overhang or pocket features without support structure because of laser beam axis direction changing. An algorithm to extract additional information on surface contours and generate tool path has been developed for 5-axis laser manufacturing. A series of contours points information with position and its unit normal vector or tangent vector information was extracted. The laser beam center point position (x_m,y_m,z_m) and laser axis vector (i_m,j_m,k_m) through the direct slicing can be extracted. Then by post-processing, the geometrical data (x_m,y_m,z_m,i_m,j_m,k_m) (m=1,2,...n) can be transformed into 5-axis machine coordinate for generating CNC code to control tool movement . This work is the basis of 3D Laser direct manufacturing and re-manufacturing.Finaly the application of coaxial nozzle and developed CAM system in Laser direct manufacturing and re-manufacturing are introduced .It shows that the laser manufacturing will have expansive application.