Metallography of metal injection molded parts is often used to discover the causes of poor mechanical performance or other problems. This is usually done on the finished part which has seen all of the processing steps associated with MIM. Experience has shown that identifying the process step which introduced a defect is difficult by looking only at the finished parts. Greater information can be gained by looking at the parts at different stages in the MIM process. In order to accurately determine the microstructural characteristics and assess manufacturing procedures, it is important to be able to look at a representative microstructure. In particular for MIM parts, when the components are in a green or debound state, prior to sintering, the focus is on developing a preparation method that minimizes the pull out of loose particles. Several variables that influence the accuracy of the preparation procedure have been examined in this study. These include sectioning, mounting media, abrasive format (fixed vs. loose), and depth of grinding. Image analysis techniques were used to benchmark the different preparation methods by comparing the relative fraction of binder and metal powder as observed with the known feed stock mixture.
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