Abstract
Rapid Prototyping methods currently in use are based on solidifying polymers by UV laser irradiation. The availability of these methods has altered the environment for product development as cycle times for component revisions are reduced from several days down to several hours. However, a common feature of most Rapid Prototyping Processes is that these parts are suitable for space studies but face severe restrictions for functionality tests. E.g., an exhaust part, made out of plastics, cannot be exposed to high temperature fumes.
At this point, an intermediate step must be taken, original parts must be manufactured and tested, what often means casting of soft tools for these original parts. This second step, essentially a “detour”, is a characteristic feature of many such processes.
Subject of this presentation is a one-step Rapid Manufacturing Process to create 3D prototyping parts, using the original sample material. The goal is to investigate the fundamental characteristics of the process in order to understand the effects of various process variables on different physical parameters. Parts created in such a manner could be readily used for real testing. Preparations of an experimental setup where metal powder is fed to the laser beam-material interaction region have been concluded. The powder is melted and forms planar, two-dimensional geometries as the substrate is moved under the laser beam in XY-direction. After completing the geometry in the plane, the substrate is displaced in Z-direction, and a new layer of material is placed on top of the just completed deposit. By continuous repetition of this process, 3D parts were created. From an end-user’s point of view, the step of using soft tools can be avoided.
A high power CO2 laser was used as energy source, the material powder under investigation was Stainless Steel SS304L (particle size 140 μm). Helium was used as shield gas at a flow rate of 15 1/min. The incident CO2 laser beam power was varied between 300 W and 400 W, with the laser beam intensity distributed in a donut mode. The laser beam was focused to a focal diameter of 600 μm.
