Length of Cycle Versus Quantity of Material Processed Beneficial Conditions for
Debinding / Sintering Question Existing Parameters and Reasoning
Debinding
Benefits of Partial Pressure
Binder Removal
Flow Paths
Temperature Uniformity
Time
Debinding
Efficiency at 300° C
The plot below represents
the average temperature of six separate thermocouples surrounding
a part during low temperature debind for a period of one
hour at 300º C
under a 300 torr partial Pressure.
Clearly, the efficiency will be improved with
hydrogen as your time at temperature will be greater as your time at temperature will
be greater as long as the
Binder/Alloy combination can be debound under Hydrogen.
Debinding
Efficiency at 600° C
The plot
below represents the average temperature of six separate thermocouples
surrounding a part during debind for a period of one hour at
600ºC under a 300 torr partial
Pressure. Here the efficiency is improved with nitrogen
as your time at temperature will be greater. This illustrates
the importance of knowing the processing keys and Binder/Alloy
compatibility with gasses and partial pressure.
Sintering
Oxide Removal
Temperature Uniformity
Densification
Flow Paths
Carbon Control
Sintering
Efficiency
Here we find that the lighter molecule is
detrimental to achieving temperature at a 5ºC/Min. ramp rate as it
takes nearly 20 minutes longer to level off with Hydrogen
Case I
Cycle time Improvements of 75%
Elimination of Separate Thermal Debind Step
Improved Shape Retention
Improved Dimensional Control
Cycle
Comparison for Case I
Note that in the time it took
to run one existing cycle, the optimized cycle could be run nearly
four times, each one with a greater quantity of parts than the
existing cycle.
Case
II
Improved
Properties
Improved Density
Significant Shorter Process Time
Microstructure
Comparison for Case II
Original
Process Indicates Over-Sinter
High Porosity
High Oxygen Content
Case
III
Elimination of Separate Thermal Debind Step Increased Final Part Consistency
and Repeatability Improved Carbon Control Reduced Utility Consumption
Profile
Comparison for Case III
Substantially
Shorter Cycle
Reduced Part Handling
Improved Carbon Control
Ability to Use Hydrogen
Case
IV
Titanium is a much sought
after alloy in the MIM Industry. Not only were we able to successfully
thermally debind and sinter titanium alloy parts, but we shortened the
thermal debind and sinter by 54%. In addition, the optimized cycle
provided an improved structure, smaller grain size, and reduced porosity over
the incumbent process.
Both Micrographs are Un-edged, Orange filter for contrast
Case
V
Decreased Process Time and Utility Consumption
Excellent Shape Retention and
Dimensional Control
High Hardness and Materials Properties Out of the Furnace
Post
Processing Techniques
Ways to Reduce Handling and “Add On” Steps
Creative Setter Designs to Minimize Coining or Sizing
Quench After Reaching Solution Temperature for Some Alloys
Age Parts Before They are Removed from the Furnace
DSH Technologies, LLC 107 Commerce Road
Cedar Grove , NJ 07009
