Study on Local Powdwer Characteristics for an Index of Packing and Compression in Powder Compression Molding Process

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04813
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 27010:Transport phenomena and unit operations-related
• Research Institution: Okayama University
• Principal Investigator: Gotoh Kuniaki 岡山大学, 自然科学研究科, 教授 (20215487)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 重力流動 / 流動性評価 / 隅角充填性 / 粉体圧縮成形 / 圧縮圧伝播 / 金型形状

Outline of Final Research Achievements

The compression molding of powder has been used in various manufacturing processes such as tableting of medicine and powder metallurgy, and many studies have been reported. In such powder handling process, it is said that the powder behavior on the mesoscopic scale dominates the macro behavior, but the powder characteristics on the mesoscopic scale, that reflects local powder characteristics, have not defined. In this study, the evaluation method for local powder characteristics and characteristic indexes were proposed although the indexes can be applied to only on a gravity flow during a compression molding operation. Regarding the pressure propagation in the compression molding, the local propagation pressure was measured. It was found that the pressure propagation in the mold was anisotropic within the particle elastic deformation region, and the pressure propagation ratio in the compression direction and the side wall direction was a particle characteristic.

Free Research Field

粉体工学

Academic Significance and Societal Importance of the Research Achievements

微小固体の集合体である粉体の操作においては，１個粒子をミクロスケール，粒子集合体である粉体をマクロスケールとした時の中間となる，メゾスコピックなスケールでの挙動が粉体操作中のマクロな挙動を支配すると言われてきた。しかし，そのメソスコピックなスケールでの粉体特性，すなわち，局所の粉体特性は定義されておらず，評価した例もない。本研究は，金型への重力充填というシンプルな操作であるが，メソスコピックなスケールでの粉体挙動を基に，操作の指標となる特性を定義した点に学術的意義がある。