Layered Scan Design And Implementation Of 3D Model

The rapid prototyping technology is applying a 3D design software or reverse engineering to obtain a component 3D model and using the approximate process to generate a file type recognized by a slicing software,such as the STL format.The next step is selecting the appropriate layering method to slice the processed model for obtaining the contour information of the part.Then,the rapid prototyping system according to the contour information scans layer by layer to form the solid part.The layer scanning to a 3D model is a significant process in rapid prototyping,for the accuracy of a model is determined by the approximate process and the layering method,and the motion scanning process determines the shape of the component.Based on the 3D model,we establish a rapid prototyping system for the equipment and process research using plasma arc as the heat source in this project.First,we create a 3D model and make some approximate process for it.Then,the model is sliced in layer.Finally,the plasma torch carried by the motion control system scans layer by layer according to the slice profile to finally get the component.For the 3D rapid prototyping technology,the General research contents are as follows:First,the component 3D model designed by the SOLIDWORKS software is approximately processed to obtain the STL format file.By analyzing the effects of rapid prototyping result from different slicing algorithm,the STL model is selected and its slicing process is researched in this program.The STL 3D model is sliced in layer according to the geometric topological information algorithm in order to generate a series of ordered contour information(G code)of the model.The essence of model slicing is to reduce the dimensions,which is also renamed that 3D model is represented by a set of two-dimensional slices.Secondly,with the use of a peripheral circuit,a rapid prototyping motion control card with the ATMEGA2560 microcontroller as its processor is designed.During the rapid prototyping process,the control card is connected with the host computer through data bus to obtain the G code and drive the step-motor to rotate by compiling and generating the pulse signal.A 3D motion platform is built by using ball screws and step-motors.The three pulses produced by the control card respectively control the three step-motors to move harmoniously and achieve the scanning of the layered information of 3D model.Thirdly,a plasma arc heat source control system is built with PLC as the control core.The system is mainly composed of two major modules,which are preset parameters module and automatic control module.The main function of the preset parameters module is to debug and set parameter.The automatic control module cooperates with the motion control system to achieve the open and close of the plasma arc in the rapid prototyping process.Then,the process testing using the rapid prototyping system is to verify this system stability and to find suitable rapid prototyping process parameters.In the experiment,the Q235 steel plate with thickness of 6mm is used as forming foundation,and AWS A5.18 ER70S-6 wire with the diameter of 0.8mmis selected as a filler material for rapid prototyping tests.Finally,the feasibility and stability of the rapid prototyping system are verified through process tests.The motion system could accurately scan according to any three-dimensional model designed by the host computer.The PLC control system can ensure the plasma heat source to work stably during the rapid prototyping process.On the other hand,the experiments with DC plasma arc and pulsed plasma arc are used to research rapid prototyping process for analyzing the effects of different heat input,current,and wire feed speed on prototyping results.