Mechanism And Experimental Research Of Selective Laser Sintering For Engineering Plastics Powder

The Rapid Prototyping is a high technology combined CAD/CAM, laser application, materials, photo chemistry, numerical control technology, which effectively improved the production efficiency and manufacturing flexibility. With the development of the technology, SLS as one of its typical process , has the advantage of wide range of forming materials, Short production cycle and good prospects for engineering applications, etc. And also received more and more wide attention.By analyzing mechanism of engineering plastics laser sintering, this paper discussed the three-dimensional analytical model of non-steady-state temperature field for powder material, which has pore structure characteristics, discussed the discipline of thermal parameters which changes with temperature, on this basis, experimented with the point,line,surface, and realized three-dimensional structure sintering; and combined with the principles and characteristics of the laser sintering, developed the rapid prototyping machine for laser sintering of plastic powder.Firstly, discussing the effect of laser sintering of powder form and process, combined the theory and experiment, the discipline of thermal parameters which changes with temperature was obtained; through further analysis of the transient of Laser sintering effect, on the base of the model of objects in the semi-infinite with point heat source and moving plane heat source was established, the temperature field model of laser sintering can be established.Secondly, according to the principle of laser sintering and each part function of the process, completed the structural design and selection, including two-dimensional optical scanning table, providing powder device, heat and insulation device, the support platform and framework structure, etc.Finally, with the guide of sintering temperature field, through the optimization of process parameters with point, line and area, such as laser power, scanning velocity, scanning spacing, powder thickness, etc, realized the sintering of three-dimensional structures.Through the above working, initially obtained sintered specifications of nylon powder (PA6), provides a good basis for the three-dimensional structure (parts) of the sintering, and playing a guiding role to the optimization of other sintered materials.