The principle of CNC rapid prototyping
Selective laser sintering (hereinafter referred to as SLS) technology was originally proposed by Carl Ckard of the University of Texas at Austin in 1989 in his master's thesis. After the American DTM company launched in 1992 the process of commercial production equipment Sinter Sation. For decades, the University of Austin and DTM have done a lot of research in the field of SLS, which has yielded fruitful results in the development of equipment and technology and materials.
Selective laser sintering is the use of laser selectively layered sintered solid powder, and the formation of sintered layers of solidified layer superimposed to produce the required shape parts. The whole process includes the establishment of CAD model and data processing, powder laying,CNC rapid prototyping sintering and reprocessing.
The whole process device consists of a powder cylinder and a molding cylinder, and a powder cylinder piston (a powder-feeding piston) rises, the powder is spread evenly on the forming cylinder piston (working piston), and the computer controls the two-dimensional scanning trajectory of the laser beam according to the prototype slicing model, and selectively sintering the solid powder material to form a layer of the part. After the powder finishes one layer, the working piston drops a layers thick and the dusting system spreads the new powder. The laser beam is controlled to scan the new sintering layer. So cyclic, layers superimposed until the three-dimensional parts are formed. Finally, the sintered powder is recovered into the powder cylinder and the molded parts are removed. For metal powder laser sintering, before sintering, the whole working table is heated to a certain temperature, which can reduce the thermal deformation in the molding and facilitate the bonding between layers.
Compared with other CNC rapid prototyping (RP) methods,CNC rapid prototyping the most prominent advantage of SLS is that it uses a wide range of molding materials. Theoretically, any powder material that can be bonded between atoms after heating can be used as SLS material. At present, the successful SLS processing materials are paraffin, polymer, metal, ceramic powder and their composite powder materials. SLS is more and more widely used because of the variety of SLS materials, the saving of materials, the wide distribution of forming parts, and the need to design and manufacture complex support systems for many purposes.