apex advanced technologies, inc. presented by: dennis hammond contributor richard phillips using a...
TRANSCRIPT
Apex Advanced Technologies, Inc.
Presented by: Dennis HammondContributor Richard Phillips
Using a highly effective lubricant in combination with a polymeric additive to minimize
cracking and address other process related problems
Presentation Outline• Overview of Superlube™, key
characteristics
• Overview of Enhancer and use
• Cracks/improved compactabilty
• Other processing problems
• Conclusions
Superlube™ Characteristics• Lubricant enters with the powdered metal as a
solid. Then transforms from a solid to a viscous liquid with shear, temperature, and pressure in the press
• Lubricant shear thins directly with shear stress• Direct results from solid to liquid transformation
– High density achievable - 7.2 to 7.4 g/cc– Low use levels required - typical 0.4% or less– Excellent lubricity - film of viscous liquid
versus slide on a solid particle
Direct results
• Up to 50% reduction in ejection force
• Tool wear decreased due to better lubrication and/or lowering of tonnage
• Surface finish improved
• Improved physical properties of final part by 15 - 20%
Direct Results Cont.
• Powder movement to equalize green density, near hydrostatic conditions in compaction (98-99.5vol. %)
• Minimization of density gradients in the part
• Elimination of micro-cracking• Reduces the risk of molding cracks• Staggered decomposition in burn off• Excellent dimensional stability of sintered
parts
Enhancer Characteristics
• Clean burning, no ash• Primary function is to occupy space,
secondary is lubrication• Needs to deform with no interference to
metal compressibility up to 100% vol.• Helps to improve green strength up to
100%- improved crack resistance• Compatible with mixing, compaction and
processing• Favorable cost / specific gravity ratio
Methods Used
• Predictable method based on calculation to optimize lubrication using lubricant and enhancer, target 98-99.5 Vol. %, near hydrostatic conditions
• Lubricant functions as die wall and internal lubricant simultaneously
• Enhancer used to occupy space, deform under load to enhance green strength
Cracks
• A crack can be defined as a break in interparticle bond between powder particles
• The bond may have been broken during processing or may have never been formed
• A major issue in P/M processing
• Once formed cannot be fixed
Cracks Root Causes
• Improper material composition
• Interparticle side shifting action
• Improper elastic strain release
• High tensile/shear stress
The Common Cracks in Green P/M Compacts
• 59 case studies of parts• When cracks were formed - In 19 cases during compaction - In 43 cases during ejection• Materials solutions - 18 cases increased green strength - 11 cases better lubrication - 4 cases improved powder compressibility - 2 cases better uniformity in compact - 2 cases improved handling
Crack Causes, Material Controlled
• High ejection load – better lubrication
• Low green strength - increase up to 100%
• Density gradients - near hydrostatic, limited lateral movement, 99% vol.
• Non-uniform porosity - small uniform pores
• Over compaction - movement in transition areas
Volume % vs. slideon Formulation FLN2-4405 at 7.0 g/cc G.D.
1175
1275
1375
1475
1575
1675
1775
1875
1975
Slid
e (L
bF
)
Slide 1875 2025 1992 1550 1400 1400 1325 1175
91.98% 96.93% 98.44% 98.94% 100.60%101.64%
0.75% Keno lube
0.75% Acra wax
- 0.35% -
0.35% 0.15%
0.35% 0.35%
0.35% 0.50%
0.35% 0.65%
0.35% 0.80%
Lube:
Enhancer:
Volume %:
Enhancer Effect on Ejection, Slide, and G.D. on A1000C at 60TSI
1400
1600
1800
2000
2200
2400
2600
Pea
k/S
lide
(TS
I)
7.23
7.26
7.29
7.32
7.35
7.38
7.41
7.44
slide 2583 1850 1625 1683 1458
G.D 7.37 7.42 7.41 7.38 7.30
97.34% 98.56% 100.00% 100.53% 101.29%Volume%
Green Strength
• Green strength increase directly with increased G.D.
• The more lubricant, the worse the green strength
• Green strength dependent on particle shape, irregularity and hardness
• Green strength dependent on type and amount of solids in the P/M mix
Green Strength
• Superlube™ is squeezed from between the particle surfaces
• Enhancer is deformed for best fit• The combination gives a unique mix that
allows for high green strength as well as excellent lubrication
• Combination used to achieve 99-99.5 vol. % at target density, the higher the density or the more volume occupied the less Enhancer is used
Acrawax Volume %: GS, TSIBase Iron ABC 100.30 at 7.0 g/cc
35
40
45
50
55
TS
I
1000
1500
2000
2500
3000
3500
4000
Green
Stren
gth
TSI 36.8 36 36.8 50
G. S. 3962 1785 1430 1336
Volume 89.29%
Volume 94.74%
Volume 97.41%
Volume 99.56%
0.35% Superlube + Enhancer Vol%: GS, TSI Base Iron ABC 100.30 at 7.0 g/cc
25
27
29
31
33
35
37
39
TS
I
2,000
2,100
2,200
2,300
2,400
2,500
2,600
2,700
Gre
en
Stre
ng
th
TSI 32 32 32 32 32
G. S. 2,005 2,229 2,301 2,459 2,673
Volume 91.98% Volume 94.00% Volume 95.20% Volume 97.40% Volume 99.60%
Medium Density/ With Enhancer, Crack Elimination
• FN-0205, .4%lube, .4% enhancer, gear with spokes / hub ~4inch O.D; ~1.75inch height, 7.0 g/cc, driver crack elimination, 98% volume at density
• FC-0208, .4% lube, .25% enhancer,
multi-level part, 2 inches height transition to .5 inches, 7.0 g/cc driver crack elimination, 99% volume at density
Medium Density/ With Enhancer, Crack Elimination
• Proprietary formula, .4% lube, .35% enhancer, large part ~ 6.5 lbs, sprocket 7.0 g/cc crack elimination, 50% reduction in ejection forces, 99% volume at density
• Proprietary formula, .4% lube, .25% enhancer, large 4 level, 5 in. O.D; 2.25 in. high, 2.5 LBS, 7.05 g/cc, crack elimination plus the ability to eject from the die, 99% volume
Processing Problems Addressed with Superlube™/
Enhancer• Dimensional stability
• Die Wear
• Highly effective copper infiltration
• Elimination of blistering on high nickel formulas
Dimensional Stability
• Dimensional Stability - uniform, predictable size change after sintering
• Minimization of density gradients in the part - near hydrostatic conditions
• Particles rearrange during full compaction cycle for best fit - small uniform pores
• Dimensional stability plus superior physical properties; fatigue, strength, hardness
Medium Density, Blistering, Die Wear, Gradient
• FN-0205, .3% lube, .45% enhancer, .7 inch O.D; 1.25 inch height, 7.05 g/cc, driver blistering problems, 98% volume
• 45P base, .4% lube, .35% enhancer, 3inch height, 7.1 g/cc, driver die wear, 99% volume
• 45P base, .4% lube, .25% enhancer, 1.75 inch height, 7.17 g/cc, driver high density/density split minimization, 99% volume
Medium Density, Gradient Infiltration
• FN-0205, .4% lube, .25% enhancer, inside gear ~4inch O.D. ~ 2inch height, 7.1 g/cc ~35 TSI, driver density split, dimensional stability, 98% volume at density
• FLC 4608, .35% lube, gear 1 inch O.D; .65 inch height, 7.2 g/cc, 98.5% volume, copper infiltrated, 7.67g/cc
High Density
• Density better than hot, warm compaction and die wall lubrication
• Superior physical properties
• Elimination of double press / double sinter
• No special equipment or setup required
• Increased process capability
Crack Elimination/ Minimization
• 6.9 - 7.4 g/cc density range• Lower ejection – up to 50%, lower stress on
part• Higher green strength, up to 100%• Near hydrostatic conditions - minimize over
compaction in transition areas• Minimization of gradients• Small uniform porosity• Elimination of micro - cracking
Increased Compressibility
• Compressibility up to 30% higher
• Larger parts in an existing press
• Less stress on tools
• Less wear on tools
• Extended life of press components
Environmentally Friendly
• No metallic Stearates
• Staggered burn out - less gas out at one time
• Pores are not closed - better out gassing - near hydrostatic conditions
• Improved furnace though put
Better Lubrication
• Sliding on film of viscous liquid / verses solid particle
• Tool wear >25% increased life
• Slide forces significantly lower than with conventional solid lubricants – as much as 50%
Predictable
• Lubrication needs are known before going on the press
• Density is calculated before going on the press
• Press tonnage is known before going on the press
• Streamlines the process of quotation, development and problem solving