Injection Molding Skim Research And Mim Stainless Steel

Debinding is the key of MM technology. By comparing the scanning electronic micrograph, thermal debinding behavior of PW-EVA-HDPE-SA binder from the as-molded stainless steel parts was studied. By contrasting the as-molded and debound parts' SEM pictures, we found out that with the process of debinding, small particles would move to the surface because of the difference of cavity force. We also found out that initial pores would emerge when as little as 4% binder had been removed. In the initial stage of thermal debinding, vapor tension varies in different place due to the difference of curvature, thus more binders would be removed in places with smaller cavity between metal powders.Thickness is one of the elements affecting debinding speed and efficiency, by analyzing the kinetics of thermal debinding, shifting of different controlling mechanism was found in the debinding process. The definition of critical thickness was specifically brought forward for the first time in this article. Big critical thickness means fast initial heating can be performed, which means the time for debinding can be comparatively shorter. To avoid defects such as blisters, cracks and distortion, heating of compacts with small critical thickness should be very slow. In debinding practice big critical thickness is more favorable. Theoretical calculation of controlling steps show that critical thickness depends on the flowing factor: powder size, debinding temperature and solid loading; it's directly proportional to powder sizes, it's inversely proportional to temperature and solid loading rate.In debinding practices, big temperature ramp usually results in defects such as distortions, bubbles and cracks. By analyzing the formation mechanism of debinding defects, a defect-predicting model was brought out and experimentally confirmed.At present MIM practice, powder accounts for a great part of the total costs. In the manufacturing of MIM stainless steel, gas-atomized powder dominants the powder market. Water-atomized powder is much cheaper than gas-atomized powder. By comparing the MIM of both powders, an attempt to replace gas-atomized powderwith water-atomized powder was made.MEM stainless steel is widely used in the medical field, but this material often contains Ni, to which many people are allergy. MM processing of Ni-Free stainless steel was studied in this paper.Corrosion-resistant property is a very important property of stainless steel. Reports on the stainless steel's corrosion-resistant properties are still very few. Byusing HC1 socking, Feroxyl ranking, and anode voltage detecting, comparison of the corrosion-resistant properties between MM stainless steel, founded stainless steel and P/M stainless steel was made.