Effects of lubricant and part geometry on the ejection characteristics during die compaction

ABSTRACT

The ejection of a part following die compaction is a critical step in manufacturing powder metal and ceramic parts as well as pharmaceutical tablets. In this paper, the ejection of die-compacted hollow cylinders of heights 0.5 and 1.2 cm from Fe–2%Cu–0.5%C powders mixed with various amounts of (0.2–0.8 wt-%) of ethylene-bis-stearamide (EBS) was studied to understand the effect of lubricant amount and part geometry on the ejection process. Additionally, the ejection data of gears of 0.5 and 1.2 cm die compacted from Fe–2%Cu–0.5%C powders with 0.8 wt-% EBS was analysed to understand the effect of geometry on the ejection process. Several ejection parameters were found to be sensitive to the amount of EBS as well as the size and shape of the parts. The results from the present study indicated that the major portion of the ejection cycle involved the movement of the part within the die.

KEYWORDS:

• Die compaction
• ejection curve
• lubricant
• strip force
• slide force

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Ravi K. Enneti is working as an Principal Scientist II in Research and Development department at Global Tungsten and Powders Corporation. Ravi K. Enneti research focus is in developing W and WC based powders for additive manufacturing and wear applications.

Randall M. German is the foremost expert in sintering and an author of over a dozen books, two dozen patents and a thousand publications.

Sundar V. Atre is the Endowed Chair of Manufacturing & Materials at the University of Louisville where he is leading the development of a program connecting design, 3D printing and advanced manufacturing to entrepreneurship. Additional details can be found at uofl3dpbiz.com.