28-04-2011, 10:31 AM
presented by
MIR MUKARAM HUSSAIN
watr mukaram-2007.pptx (Size: 1.53 MB / Downloads: 1,084)
WATERJET MACHINING
Introduction to Water jet
It is the fastest growing machining process.
One of the most versatile machining processes.
Compliments other technologies such as milling, laser, EDM, and plasma.
True cold cutting process – No HAZ , mechanical stresses or operator and environmental hazards.
Not limited to machining – but also used in food industry applications.
Evolution of Waterjet :
1930s: Mining Industry to remove stones and coal
1960s : Need to cut advanced materials for aerospace industry
1970s : First attempts were to employ WaterJet to cut advanced composites for aerospace applications.
1980s: First commercial AWJ machines
PRINCIPLE OF WORKING
Fig. Structure of a water jet machining.
TYPES OF WATER JET CUTTING
Water jet cut
Abrasive jet cut
Abrasive water suspension jets
Water jet :
Water jets are used for cutting soft materials
Water Jet Machinable Materials
Like Soft rubber, foam, tin foil, carpet, soft gasket material
Abrasive water jet
Abrasive water jets for hard materials
An abrasive element is added to the water beam to assist cutting
Abrasive Water Jet Machinable materials: Titanium, aluminum, stone, hard rubber,
hardened tool steel
Components
Pump
Nozzle
Orifice
Control System
Components – Pump :
50 – 100 hp electric driven pump
Hydraulic Based Operation
Pressures Up to 60,000psi (4000 bar)
Smooth Output
Components – Nozzle:
Components – Orifice:
Components – Control System
Materials:
The list of materials that a Water jet system could penetrate is significant.
To date, Applications have been used with:
Ceramic Tile, Wood , Rubber, Glass, Marble and Granite ,Foam , GIO Phenolic , Steel, Armor plating ,Urethane, Titanium , Kevlar, Aluminum , Brass , Copper, Stainless Steel , Spectra, Fiberglass , Corrugated Cardboard , Acrylic .
Surface Characteristics Variables of Cuts
Water jet Pressure
Water jet Diameter
Abrasive Material Type
Abrasive Material Size
Abrasive Material Flow Rate
Traverse Speed
The Cutting Angle
Advantages:
No heat affected zone
Stress-free cutting – No
residual stresses
Wide range of materials
Environmentally friendly
No need for surface finish
No tool changing
Minimal Fixturing Required
Cont. Advantages:
Faster than any other technique
Saves Raw Material
Flexible Machining Integration
Does Not Need a Starting Hole
Ability to Cut in Any Direction
Disadvantages:
Limited number of materials can be cut economically
Very thick parts can not be cut with Water Jet
Cutting and still hold dimensional accuracy
Slower cutting rate compared to both plasma and oxyfuel cutting processes
Higher entry cost
Comparison to other MethodsWaterJet v/s Wire EDM
Can Cut through any material
No Need for a Starting Hole
No Heat Affected Zone
Limited to Conducting Materials
A Starting Hole is
Needed for the Wire
Heat Affected Zone
WaterJet v/s Laser
No Heat Affected Zone
Can Cut Through Reflective Materials
Can Cut Uneven Surfaces Smoothly
Environmentally friendly
Can Cut Up to 12” in hard materials (Ti, SS)& 24” in Rubber
Minimal Heat Affected Zone
Reflects on Shiny Surfaces
Laser Defracts and Looses its Focu
Produces Toxic Fumes
Max. Depth 0.5 – 0.75”
WaterJet v/s Milling
Excellent Use of Raw Material
No Tool Changing
No Fixturing Required
No Cleanup is Required
Faster
No HAZ
Large Amounts of Waste of Raw Material
Frequent Tool Changing
Fixturing is essential
Requires Periodical Cleanup
Slow
HAZ
Deciding which metal Cutting System is Best?
Variables to be considered when making a decision
on the right cutting system to use :
Cutting speed
Edge cleanliness
Degree of tolerance required
Number and types of metal to be cut
Capital investment
Operating costs
Size of heat affected zone
Access to secondary machining processes
Conclusion:
It is relatively a new technology which has caught on quickly and is replacing century-old methods used for manufacturing
Used not only in typical machining applications, but food and soft-goods industries
As material and pump technology advances faster cutting rates, longer component life and tighter tolerances will be achievable
Paves the way for new machining processes that embrace simplicity and have a small environmental impact