Transcript ultrasonic machining - UNT College of Engineering

MFET 4210
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1. Basic Principles
2. Hardware
3. Abrasives
4. Parameters
5. Capabilities
6. Advantages
7. Disadvantages
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How does it work?
High pressure water with abrasive eroding material
 Small diameter orifice or “jewel” to focus energy
 Erosion of material
 Jet of abrasive and water
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 20,000 – 90,000 psi
 Up to 600 mph
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Intensifier Pump
Nozzle
Abrasive Delivery System
Catcher
CNC Control
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Intensifier Pump Components
Hydraulic Pump
 Pistons
 Cylinders
 Check valves
 Attenuator
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Nozzle
Jewel
 Abrasive inlet
 Guard
 Mixing Tube
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Nozzle
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Jewel
 Diameter ranges from .005
- .020”
 Usually sapphire,
sometimes ruby or
diamond
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Nozzle
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Abrasive Inlet
 Feeds from abrasive feed
system
 Venturi pulls in abrasive
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Nozzle
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Mixing Tube
 Abrasive and water mix
evenly
 Must be exactly in line
 Composite carbide
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Abrasive Delivery System
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Provide fixed delivery rate
Gravity or air fed
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Catcher
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Slows jet of water down
Reduces noise and dust
Catches dust
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CNC Controllers
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Traditional control
PCs
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Cheaper
Easier to update to newer and faster software
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Usage
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½ to 2 pounds per minute
$0.15 to $0.40 per pound
Types
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Garnet
Olivine
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Garnet
Most common at 80 mesh
Naturally occurring mineral
Less dusting
Typical to reuse 2 or 3 times
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Olivine
Cheaper than garnet
Softer than garnet
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Pressure
Nozzle or jewel diameter
Feed or traverse rate
Nozzle standoff distance
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Pressure
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Ranges from 20-90,000 psi
Less than 60,000 psi most common
Higher pressure for harder materials and thicker cuts
 Harder on equipment
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Nozzle Diameter
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Large range depending on application
Jet usually .020-.050”
Horsepower = 0.58*P*Q
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P = pressure in ksi
Q = flow rate in gpm
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Feed Rate
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Varies greatly depending on
 Type of material
 Thickness
 Hardness
 Quality of cut needed
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Standoff
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Usually .010 to 0.200”, up to 1”
Higher distance causes frosting
 Eliminated by cutting underwater
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Tolerances
Materials
Geometries
Examples of use
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Tolerances
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+-.004 to +-.008”
Vast majority of industry cuts at +-.010” or more
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Materials
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Cuts basically anything
Diamond, some ceramics
6.5” Ti
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Geometry
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Stacking parts
5-axis milling
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Geometry
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Very thin to very
thick cuts
Flat sheets of
material
10.25” Tool Steel
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No HAZ
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Temp may rise to 120 degrees F
Catch tank and water absorb heat
Very small kerf
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.020-.050”
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Minimal cutting forces
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5 pounds max down force
Very low side forces
Clamping forces are very low
 Brittle or fragile work pieces
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Fast and accurate
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Minimal fixturing
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Omni-directional
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Cuts any type of materials
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Nonhomogeneous
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No tools to sharpen, only “tool” is the nozzle
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Environmentally friendly
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Garnet can be dumped in landfill
Water can be filtered and reused
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Lag
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Only a factor if finish is important
Very similar to cutting torch lag lines
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Taper
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Parts cut with taper
Can be compensated for by software
Increases with nozzle wear
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Less accurate than traditional machining
Very hard materials not very practical
application
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Traverse rate is so slow, costs add up
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Can delaminate some materials
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Fiberglass, some composites
Preventable with pilot hole from drill
Cost
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Setup ranges from $20,000-$300,000
 Average machine runs $150,000
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Thickness of cut
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Price increases dramatically for >2” metal cuts
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Nozzle wear
Consumable nozzle wears
 Causes stray cutting
 Increases kerf
 Decreases finish quality
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Very loud
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Reduced if cut underwater
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Machine shops
Artists
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Aerospace
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Stone, glass, marble
Titanium, Inconel, composites
Rapid prototyping
Universities
Automotive industry
Custom flooring work
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Tiles
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Very versatile, powerful technology
Growing use and applications
Constantly getting better and more capable
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Nontraditional Machining Processes, E. J. Weller
http://www.jetedge.com
http://waterjets.org/
http://www.h2ocut.com/
http://www.universalminerals.com/
http://www.flowcorp.com/