The use of admixed lubricants for conventionally compacted PM parts has been a feature of the compaction process since its inception. During the past 50 years the industry has moved from metallic stearates to synthetic waxes and from 1% lubricant additions to much lower amounts. At the same time the industry has recognized that the lubricant burn-off by-products serve as a potential source of contamination during sintering. Many investigators seek “cleaner-burning” lubricants, more-effective lubricants (much less needed to effect ejection), and the ultimate—an all-purpose die-wall lubrication system.

In order to address many of these questions we need a consistent set of tests or evaluation methods to determine the properties of any lubrication system. Whenever a new lubricant is considered, the effect of this change on powder properties, compactability, ejection response, and sintering response must be examined. The first phase of this program will propose a unique set of test methods for the study of any lubrication system—whether admixed or die-wall. The second segment of the program will consider a series of tool coatings as a means for reducing the amount of admixed lubricant in a given powder system. Powder–tooling interaction is the largest source of friction during compaction and ejection. A lubricious coating can provide a unique capability for reducing the amount of lubricant required during conventional compaction. The program will not be examining lubricants or binders for warm compaction.

Status

This new lubrication program was approved for 2001. The Phase 1 testing was conducted at Penn State University. Initial lubrication studies used a simple, round tool set followed by a production-level compaction series using a CPMT-designed gear tool set. In Phase 2 tool coating studies will follow the same testing protocol evaluating five different tool coatings suggested by the CPMT membership.

The baseline powder, FC-0205, was supplied by Hoeganaes. The tooling was produced by a CPMT member company. The initial powder characterization studies were completed in late 2002. The Phase 1 compaction studies were completed in 2003, including admixed versus die-wall lubrication.

Phase 2 studies began in 2005 with the selection of tool coatings and the application of these coatings to the first round, cylinder tool sets. The coated tools were characterized for surface finish by SEM and texture measuring device.  The evaluation of these coatings (Phase 2) will be conducted by CNRC-IMI in Boucherville (Montreal) Canada.  A multi-task contract has been signed with IMI, with completion expected by the end of 2007.  The tool sets have been measured for critical dimensions and roundness which will serve as a baseline for wear/galling measurements following the first evaluation study.  This first evaluation series, which includes both coated tools and die wall lubrication, should be completed by the end of the second quarter 2007.