Cost effective, high density P/M parts with existing equipment

1. Cost effective, high density P/M parts with existing equipment By Dennis Hammond Apex Advanced Technologies, LLC

2. Requirements to obtain high density • The level of lubricant used must be reduced, while not negatively impacting the part or process • The lubricant must be mobile, so that it migrates during pressing • The lubricant must be more effective • The lubricant must be effectively removed during the sintering process

3. Effect of lubricant on density FN 0205

4. Physical State • Solids as a general rule increase their melting point with increased pressure • There are exceptions to the rule e.g. ice • Clapeyron - Clausius formula predicts that when the density of a substance in its solid state is less than the density of the substance in its liquid state, then the melting point of that substance will decrease when pressure is increased

5. Rheology • Rheology - Study of the deformation and flow of matter in terms of stress, strain and time • Useful in modeling behavior of a substance in a process and process control • Example - processing polymers, paints, coatings and adhesives

6. Rheology - cont. • There are different types of rheometers for different applications • We are using data from a capillary rheometer to model behavior from our lubricant

7. Heaters Capillary Rheometer

8. Most polymeric materials are pseudoplastic (shear thinning) Basic Curve Shapes

10. Rheology - cont.

11. Rheology - cont. • Conclusion - hard solid with crystallinity that flowed from a solid to a liquid under pressure • Higher temperature with pressure and shear reduced the viscosity • P/M press has speed/shear, temperature due to particle to particle friction and compaction pressure • Pressures needed are at the low end of pressure used in a press, allowing for easy rearrangement • Modeling the lubricant in a rheometer could be expected to provide predictable results in a P/M press

12. Ejection Forces • Do we have a better lubricant for P/M ?

27. Green density g/cc compared to conventional lubricants

28. Green Density Conclusions • Nice green density pick up is possible with a conventional press • No delamination or micro-cracking observed up to 65 tsi with uniform hardness and porosity of part after sintering • Slope of compressibility curve has been shifted upward • Production data is better than lab data, at low tonnage, due to friction (temperature) and speed (shear) • We get green density improvements from both effective rearrangement and from lower use levels

29. Burn Out • The ideal lubricant burns out cleanly from the furnace and in the parts, all blisters and cracks would be eliminated • Quantity and rate of emission reduced • More parts through the furnace with less problems in less time • Minimize EPA concerns

33. Sintered Properties • General Improvements as green density improves • Sintered properties are enhanced with an effective lubricant

49. Current Applications • To obtain green density comparable to die wall, hot compaction or double press without micro cracking or delamination • To replace internal lubrication in conventional die wall lubrication applications • To modify a compressibility curve to fit a press

50. Current Applications Cont. • To debottleneck a furnace operation • To run high nickel formulas without blistering or cracks • To facilitate one step copper infiltration/sintering • To obtain improved physical properties including TRS, hardness, and dimensional stability