Today we will learn about ultrasonic machining, principle,
working, equipment’s, application, advantages and disadvantages with its
diagram. Ultrasonic machining is non-traditional machining process which is
used to machine brittle and hard material. This machining process comes into existence
in 1950 for finishing EDM surface. Now this process is used in many industries
to remove metal due to its lower cost, no heat generation, and effective
machining.
Ultrasonic Machining:
Principle:
It works on the same principle of ultrasonic welding. This
machining uses ultrasonic waves to produce high frequency force of low amplitude, which act as driving force of abrasive. Ultrasonic machine generates high
frequency vibrating wave of frequency about 20000 to 30000 Hz and amplitude
about 25-50 micron. This high frequency vibration transfer to abrasive particle
contains in abrasive slurry. This leads indentation of abrasive particle to brittle
work piece and removes metal from the contact surface.
Equipment’s:
Power Source:
As we know, this machining process requires high frequency
ultrasonic wave. So a high frequency high voltage power supply require for this
process. This unit converts low frequency electric voltage (60 Hz) into high
frequency electric voltage (20k Hz).
Magnetostrictive transducer:
As we know, transducer is a device which converts electric
single into mechanical vibration. In ultrasonic machining magnetostrictive type
transducer is used to generate mechanical vibration. This transducer is made by nickel or nickel
alloy.
Booster:
The mechanical vibration generated by transducer is passes
through booster which amplify it and supply to the horn.
Tool:
The tool used in ultrasonic machining should be such that
indentation by abrasive particle, does not leads to brittle fracture of it. Thus the
tool is made by tough, strong and ductile materials like steel, stainless steel
etc.
Tool holder or Horn:
As the name implies this unit connects the tool to the
transducer. It transfers amplified vibration from booster to the tool. It
should have high endurance limit.
Abrasive Slurry:
A water based slurry of abrasive particle used as abrasive
slurry in ultrasonic machining. Silicon carbide, aluminum oxide, boron carbide
are used as abrasive particle in this slurry. A slurry delivery and return
mechanism is also used in USM.
Working process:
Now we know about basic part and idea of ultrasonic
machining. In this machining material is removed by indentation of abrasive
particle on work-piece. It works as follow.
|
Diagram of Ultrasonic Machinie |
- First the low frequency electric current passes through
electric supply. This low frequency current converts into high frequency
current through some electrical equipment.
- This high frequency current passes through transducer. The
transducer converts this high frequency electric single into high frequency
mechanical vibration.
- This mechanical vibration passes through booster. The
booster amplify this high frequency vibration and send to horn.
- Horn which is also known as tool holder, transfer this amplified
vibration to tool which makes tool vibrate at ultrasonic frequency.
- As the tool vibrates, it makes abrasive particle to vibrate
at this high frequency. This abrasive particle strikes to the work piece and
remove metal form it.
This is the whole working process of ultrasonic machining.
Application:
- This machining is used to machine hard and brittle
material like carbide, ceramic, glass etc.
- This is used in machining of die and tool of drill, wire drawing
machine etc.
- Used in fabrication of silicon nitrite turbine blade.
- It is used to cut diamond in desire shape.
- It is used machining of machining non-conductive hard
material which cannot be machined by ECM or EDM due to poor conductivity.
Advantages and Disadvantages:
Advantages:
- Hard material can be easily machined by this method.
- No heat generated in work so there is no problem of work
hardening or change in structure of work piece.
- Non-conductive metals or non-metals, which cannot be
machined by ECM of EDM can be machined by it.
- It does not form chips of significant size.
Disadvantages:
- It is quite slower than other mechanical process.
- Tool wear is high because abrasive particle affect both
work-piece and tool.
- It can machine only hard material. Ductile metal cannot be
machine by this method.
- It cannot used to drill deep hole.
This is all about ultrasonic machining principle, working, equipment's, application, advantages and disadvantages. If you have any
query regarding this article, ask by commenting. If you like this article,
don’t forget to share it on your social networks. Subscribe our website for
more interesting articles.