In electrical discharge machining , metal is removed by producing powerful electric spark discharge between the tool and the work material. this principle is followed in electric discharge machining.
Thursday, 20 July 2017
Transducers
Transducers is a device which converts one form of energy into another form of energy. In ultrasonic machining process it converts the electrical energy into mechanical energy.
Types of Transducer
The following types of transducers are used in ultrasonic machining process for the production of ultrasonic waves.
1. Magnetostriction transducer.
2. Piezoelectric transducer.
MAGNETOSTRICTION TRANSDUCER
Principle : When a rod of ferromagnetic material such as iron or nickle is kept in a magnetic filed parallel to its length is, the rod suffers a change in length. the change in lrngth in length is independent of the direction of the magnetic field and depends only on the magnitude of the field and nature of the material. this phenomenon is known as Magnetostriction effect.
Wednesday, 19 July 2017
Ultrasonic Machinig
Ultrasonic machining is one kind of grinding method. Its is also known as ultrasonic grinding or impact grinding. The term ultrasonic refers to waves of high frequency. Human ear can hear the sound waves between 20 Hz to 20 kHz. This range is known as audible range are called infrasonic waves. The sound waves having frequencies above the audible range are known as ultrasonic waves. The ultrasonic machining process is suitable only for hard and brittle materials like carbides, glass ceramics, silicon, precious stones, germanium, titanium, tungsten, tool steels, die steels, die steels, etc
Water Jet Machining
Introduction
Water jet machining process is an extension of abrasive jet machinig process, high pressure and high velocity stream of water is used to cut the relatively soft and non-metallic meterials like paper bords, wood, plastics, rubber, fibre glass, leather, etc.
PRINCIPLE
When the high velocity of water jet comes out of the nozzle and strickes the material, its kinetic energy is converted into pressure energy including high stresses in the work material. when this induced strees exceeds the ultimate shear stress of the material, small chips of the material get loosened and fresh surface is exposed.
Water jet machining process is an extension of abrasive jet machinig process, high pressure and high velocity stream of water is used to cut the relatively soft and non-metallic meterials like paper bords, wood, plastics, rubber, fibre glass, leather, etc.
PRINCIPLE
When the high velocity of water jet comes out of the nozzle and strickes the material, its kinetic energy is converted into pressure energy including high stresses in the work material. when this induced strees exceeds the ultimate shear stress of the material, small chips of the material get loosened and fresh surface is exposed.
Characteristics of Unconventional Machining Process
1. The unconventional machining processes do not employ a conventional or traditional tool for metal removal, instead, they directly unitize some of energy for metal machinery.
2. The tool material need not be harder than the work piece material.
3. A harder and difficult to machine materials such as carbides, stainless steel, nitralloy hastalloy and many other high strength, temperature resistant alloys can be machined by unconventional machining processes.
4. The machined surface do not have any residual stresses.
2. The tool material need not be harder than the work piece material.
3. A harder and difficult to machine materials such as carbides, stainless steel, nitralloy hastalloy and many other high strength, temperature resistant alloys can be machined by unconventional machining processes.
4. The machined surface do not have any residual stresses.
Unconventional Machining Processes
The Unconventional machining processes do not employ a conventional or traditional tool for metal removal, instead, they directly utilize some form of energy for metal machining. In this process, there is no direct physical contact between the tool and the work piece.
Conventional Machining Processes
In conventional machining processes, metal is removed by using some sort of tool which is harder than the work piece and it is subjected to wear. In this process, tool and work piece are in direct contact with each other. In other words, the conventional machining processes involve removal of metal by compression shear chip formation.