Principle of rapid prototyping manufacturing technology
Principle of rapid prototyping manufacturing technology
Rapid prototyping manufacturing technology is a comprehensive technology integrating material forming, CAD, numerical control, laser and other technologies. It is a system technology to realize the integration from part design to 3D solid prototype manufacturing.
The basic principle of rapid prototyping manufacturing technology is: it is a digital forming technology that can rapidly manufacture product prototypes or parts of any complexity by stacking (or stacking) materials according to the layered data of three-dimensional CAD models without any molds, cutters and tooling,Rapid prototyping manufacturing mainly includes the following four parts:
The construction of part CAD data model. There are two methods to build 3D CAD data model: ① 3D modeling based on conception. Designers use various 3D CAD modeling systems, such as pro/e, UG, Solidworks, etc., to carry out 3D solid modeling of parts, that is, the conceptual model of parts conceived by designers is transformed into 3D CAD data model. ② 3D modeling based on solid data. Designers reverse calculate and build 3D models of 3D entities by CMM, laser scanner, NMR image, solid image and other methods.
Generation of data conversion files. The CAD data model of a part is transformed by a 3D modeling system into a data file that can be accepted by the rapid prototyping system, such as STL, IGES and other format files. STL file is a file formed by discretizing the internal and external surfaces of 3D solid. STL file is easy to slice the model, so it has become a file format accepted by most rapid prototyping systems. At present, all CAD modeling systems also have the function of outputting STL files to 3D entities.
Layered slices of the model. The three-dimensional solid model is cut into two-dimensional slices along a given direction (generally along the Z axis), that is, discretization. The thickness of the sheet can be selected according to the forming accuracy of the rapid prototyping system, such as 0.05 ~ 0.5mm.
Rapid build-up molding. The three-dimensional solid is obtained by orderly and continuous superposition in the way of plane processing. With the development of RPM technology and the deepening of people's understanding of this technology, its connotation is also gradually expanding. At present, rapid prototyping technology includes all the forming processes directly driven by CAD, and the main technical feature is the rapidity of forming. The transfer forms of materials can be free addition, removal and the combination of addition and removal.
There are more than 30 specific processes of PRM technology, among which layered solid manufacturing (LOM), selective laser sintering (SLS), fused deposition modeling (FDM) and three-dimensional lithography (SAL) are the most mature technologies, and have been well commercialized.