| The purpose of this project, defined by Maetta Sciences inc., a company specialized in parts production by powder injection molding (PIM), is to optimize the parameters of wick debinding and presintering of small 316L stainless steel parts, low-pressure molded for biomedical applications.; Two groups of statistically planned experiments are conducted on small test bar and analyzed with the criteria of a good brown part: size stability related to no dimensional changes (length, width, thickness), form stability equals no defects, good resistance is measured by a transverse rupture strength test, and binder removal being evaluated by analyzing the final mass carbon content in the part.; From the seven factors first studied, the critical ones are the nature of gas and wick material, and the parameters of the presintering stage thermal program: temperature, duration and heating rate to reach it. The optimized debinding treatment for thin parts (≤ 3 mm) embedded in "PG' alumina powder under a flow rate of argon is: rise of 2,25°C/min from 20 to 450°C, rise of 3,00°C/min from 450 to 850°C, hold for 15 minutes, natural cool down. The duration of this process is half of what is usually conducted in the company. The finding of this project reveals substantial productivity gain, gas consumption savings and reduction in equipment degradation.; Kinetic's study of capillarity debinding was impossible. It is recommended that the focus of future tests should be based on critical thickness. But most of all, it is strongly suggested that green density measurements should be considered essential to new research concerning any aspect of PIM production, especially because of inhomoaeneities in the green parts originating from the actual lack of control during the mixing and molding processes. |
