Study On The Slicing Process Of STL Data Model For The Metallic Functional Parts Based On The New Laminated Object Manufacturing

Rapid Prototyping & Manufacturing technology is a high-tech developed in the late 80's, which integrates Mechanical Engineering, CAD, Numerical Control, Laser Technology and Material Science. By using it, 3D objects can be fabricated directly from CAD models automatically and rapidly. So the technology saves tremendous time, this has a deeper effect on the manufacturing industry.RP/M is outlined in this paper. The development and the problems of national and international research work are introduced. With the development of the RP/M , the key technology of RP/M focuses on how to make the mechanical machine parts, which results in the upsurge of the study on using metal materials as modeling materials. The research contents in this paper are based on a NSFC project (Grant No. 59875088), which needs that the sheet metal is used as modeling materials for rapid manufacturing of metallic functional part. In this paper, the objective and the value of the project are put forward and the slicing process of metallic functional part is studied based on new LOM.In this paper, the metallic functional part is rapidly manufactured by Laminated Object Manufacturing (LOM) process using the thicker sheet metal as the modeling materials. But the question of modeling precision in the LOM must be solved.Modeling surface is approached by stair up of lines in the current LOM process, so theoretical manufacturing error and remaining material quantity are greater. The higher precision and lower remaining material quantity are ensured by using the thinner slicing thickness. A new LOM process, in which the slice sheet is cut along the tangent of normal section line in z-axis direction, is proposed to reduce the theoretical manufacturing error and remaining material quantity. The effects of new LOM process can increase the thickness of the laminating layer from 0.05-0.10mm to 1.0mm grade, almost same or lower theoretical manufacturing error and remaining material quantity than current LOM process can also be gotten. In order to reduce the theoretical manufacturing error and the quantity of slice sheet further, an adaptive slicing approach of changing the thickness of laminating layer is also presented.Whether the data model in STL files is correct can effect the realization of the following process. The transformation and the process of the CAD data model is introduced in this paper. The criteria to evaluate the validity of STL data model and thetype of STL data model fault are analyzed in detail, the typical fault types are listed here. An automatic diagnosis method for the STL data model is presented.The slicing process of STL data model based on new LOM is studied in this paper: the position relation between triangle facets and slicing plane is discussed in detail; the start and end points of the intersection line segments are regulated; the intersection of triangle facets and slicing plane is processed; the section contour is connected by intersection lines; adaptive slicing is realized by the calculation of the position of tangent plane of modeling surface, the angle of between the normal section line and the slicing plane , the curvature of normal section line in z-axis direction and radius of curvature.