TEAM 11 ULTRASONIC MIXER n Team Members: u Katie Kaser - Introduction & Concept Generation u Moshe Solomon - Concept Selection u Joanna Pirnot - Concept Development u Lihong Xu - Budget Sponsor: Fraunhofer USA Advisor: Dr. Michael Keefe Jump to first page
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Mechanical Mixers • Size • Cost • Wear • Contamination • Maintenance Jump to first page
Mission Design a non-mechanical mixer for homogenizing powder injection molding feedstock by April 1999 n Approach: u Identify wants and constraints u Benchmark previous technology u Generate set of concepts u Select best concept u Execute design via best engineering methodology Jump to first page
Customers n n Sponsor - Fraunhofer Mixer suppliers u Misonix n Inc. Ultrasonic consulting companies u Advanced n Sonic Processing Systems Anyone involved in powder injection molding Jump to first page
Wants & Constraints n Top 5 Wants Temperature Control u Low Contamination Level u Ease of cleaning u Cost u Produce measurable quantity u n Constraints Completion by April 1999 u Produce homogenous mixture u Safety u Jump to first page
System Benchmarking n n Mechanical Mixers High Shear Mixers u Static mixer u Pump/internal obstacle mixer (Sonolater) n Ultrasonic Mixers u Probe-type u External sound source Jump to first page
Metrics n Want n Metric u Temperature control range u Low contamination level u Percentage contaminants u Handle variety of materials u Viscosity range Jump to first page
Functional & Ultrasonic Benchmarking n Functions u Feeding u Heating u Mixing u Cooling n Ultrasonics u Ultrasonic Generators u Transducers Jump to first page
What did we learn? n Ultrasonics is a significant source of heat n Heating and mixing should be as concurrent as possible n n n A system incorporating a probe is subject to contamination and wear on the probe More energy reaches the material to be mixed using a probe than transmitting through walls of a vessel Ultrasonics are capable of mixing solid powders in a polymer resin. u On the macroscopic level a homogenous mixture was achieved Jump to first page
Target Values n Metric n Target Value u Temperature control range u 0 to 200 degrees C u Volume loading metal powder u 60% u Ease of cleaning u Time to Disassemble Jump to first page
Critical Functions n n Feeding Heating Mixing Cooling/Removal Jump to first page
Concept Generation n n Rotating Mixer Opposing Sound Sources Probe-type ultrasonic mixer Separate heating/mixing chamber Hexagonal tube mixer Jump to first page
Concept 3: Rotating Mixer Jump to first page
High Intensity Ultrasonic Processor Jump to first page
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CONCEPT SELECTION SSD RESULTS TARGET VALUES CONCEPTS 1 2 3 4 5 WANTS METRICS SUITABLE TEMPERATURE OF THE MATERIAL BEING MIXED 0 TO 200 DEGREES CELSIUS 1 4 4 4 5 AVOID CONTAMINATION DUE TO ABRASION % CONTAMINANTS IN THE PRODUCT LESS THAN 3% 5 3 4 AVOID CONTAMINATION DUE TO AN EXTERNAL SOURCE % CONTAMINANTS IN THE PRODUCTS LESS THAN 3% 2 4 4 EASY TO CLEAN ABILITY TO DISASSEMBLE, CLEAN BY HAND, & KEEP WARM WHILE CLEANING 0 TO 100 DEGREES CELSIUS 5 5 5 3 4 4 2 3 4 4 VARIETY OF MATERIALS VISCOSITY 0 - 1000 Pa-s 5 2 2 REASONABLE COST MUCH LESS THAN A MECHANICAL MIXER LESS THAN $5000 5 1 1 PRODUCE A MEASURABLE QUANTITY OF MATERIAL OUTPUT / HOUR GEATER THAN OR EQUAL TO 5 LBS/HR 2 3 3 2 5 REPEATABLE PERFORMANCE RELIABILITY LOW STANDARD DEVIATION IN MIXING RESULTS 4 4 4 PRODUCE FEEDSTOCK IN USABLE FORM GEOMETRY OF THE PRODUCT PELLET OR SPHERICAL SHAPE 5 2 3 2 5 AVOID WASTE MATERIAL WHEN CLEANING % OF MATERIAL LOST LESS THAN 5% 5 3 4 CONTROLED FEEDING MECHANISM % OF MATERIAL LOST 0% 5 Jump to 3 3 3 4 first page
Concept Selection Evaluation of Wants (Scale 1 -5, 5 being the highest score) n n n 1 st (probe type mixer) - 54 pts 2 nd (opposing sound sources) - 40 pts 3 rd (rotating mixer) - 43 pts 4 th (separate heating and mixing) - 37 pts 5 th (hexagonal tube mixer) - 49 pts Jump to first page
CONCEPT SELECTION CRITICAL FUNCTIONS FEEDING · Automatic Feeder Unit · Trough HEATING · · Double Walled Vessel with Inlet and Outlet for Water Circulation Heat Exchanger Fluid Pumping System Jump to first page
CONCEPT SELECTION CRITICAL FUNCTIONS MIXING · 600 Watt Ultrasonic Probe · Booster Horn REMOVAL / COOLING · · Teflon Stopcock Conveyor Belt · Collecting Pan Jump to first page
Concept Development n Demonstration (Video) n Test Results u Critical Functions u Prototype vs. Target Values n Modifications/Suggestions Jump to first page
Feeding n Capabilities u Automated feeder sufficiently transports powder to the mixing vessel n Limitations u speed of feeder u Residual amount of material remains on the surface of the funnel and feeder tubing Jump to first page
Heating n Capabilities u sufficiently melts materials with a low melting point F u u ex. Paraffin sufficiently removes excess heat produced by ultrasonic processor sufficiently keeps materials warm during removal n Limitations u the variety of materials (with a high melting pt. ) F u temperature range 0 to 100 degrees Celsius F u ex. Polypropylene due to probe limitations the heating fluid (water) is incapable of temp. higher than 100 degrees Celsius Jump to first page
Mixing n Capabilities u Solids Loading F F F u Limitations u Satisfactory homogeneity • microscope examination • melting (consistency) • capillary rheometer No degradation of polymer of deposits of powder Volume no greater than 50 ml F u u splashing occurs Amplitude of the Horn must be 65% F Product F u Original Design • 20% solids loading Shape of the vessel • 35% solids loading Shape of vessel and Booster Horn • 60% solids loading n splashing occurs Variety of materials F only soft materials, otherwise erosion of the tip occurs Jump to first page
Removal of Material n Capabilities u regulating flow of the material F flick valve u material is removed within 2 minutes u Limitations u If the flow is too slow, material tends to solidify prior to exiting the vessel no excess heat is required u n 96% of material is recovered F prior to cleaning Jump to first page
Cooling n Capabilities u u u material does not solidify prior to contact with the conveyor belt Air cooling is a sufficient method of cooling feedstock the material is in a usable form n Limitations u conveyor belt must be set horizontally F u material flows too quickly speed of conveyor belt must be on the lowest setting F material not cooled upon reaching the end of the conveyor belt Jump to first page
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Modifications/Suggestions (addressing our limitations) n Feeding u use n spherical shaped powders Heating u purchase F allows an air cooling converter probe to safely reach higher temperatures u use a fluid capable of reaching a higher temperature Jump to first page
Modifications/Suggestions n Mixing u purchase a larger vessel to increase the output/hour (no greater than 250 ml batches - probe tip (1/2 diameter) u purchase a larger probe tip - 1 in diameter (capable of mixing volumes up to 1000 ml) u coat the tip of the probe with tungsten carbide F this will reduce the erosion of the titanium tip Jump to first page
n Removal u Apply heat to the nozzle area to eliminate faster cooling of material; use heating gun n Cooling u Use longer conveyer belt; current length insufficient for air-cooling of larger pelleted feedstock Jump to first page
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Budget All Budgeted Material and Equipment Expenditures Estimated Upgrade Cost Engineering Development Time Conclusion Jump to first page
All Budgeted Material Projected Production Cost: $15520. 99 Total cost for the project: $520. 99 Jump to first page
Estimated Upgrade Cost Total upgrade cost: $6670. 99 $50 K to $70 K $6700 Jump to first page
Engineering Development Time Fall 10 hr/person/week for 13 weeks Winter 4 hr/person/week for 4 weeks Spring 12 hr/person/week for 10 weeks (include testing time 4 hr/person/week for 6 weeks) Total time: 1064 hours Jump to first page
In Conclusion. . . A great team gained experience from the opportunity to use engineering theory in a practical way, developing an innovative technology solution meeting the specific real-world wants of our industrial customer. . . Jump to first page
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