Powder Flowability Evaluation with Die Filling Testing Devices

Commonly, flow rate (ISO 4490, JIS Z 2502, MPIF Standard 3) is used to evaluate powder flow. However, it may not be possible to measure flow rate because powder is not discharged from the orifice, and sometimes flow rate does not correspond to the actual production of parts in terms of productibility or weight variation. To examine the evaluation method of powder flow for die filling, we conducted measurements using evaluation devices (die filling testing devices) which are close to the actual die filling of pressing machines, owned by three powder producing member companies of the Technical Committee for Metal Powders of the Japan Powder Metallurgy Association. In addition, the powders used for this evaluation were those used in actual production by three member companies who manufacture components, from the same committee. As a result, it was found that appropriate quantitative evaluation is possible within the range of standard parameter conditions. On the other hand, it was also found that valid evaluations could not be obtained outside this range. We would like to discuss the possibility of standardization by further limiting parameter conditions.