In this blog we’ll be looking at abrasive jet machining process Abrasive jet machining process is abbreviated as AJM Another name for abrasive jet machining is micro abrasive blasting Abrasive jet machining is an unconventional manufacturing process now.
Let’s take a look at the principle(sorry for wrong spelling in video) of abrasive jet machining Principle. Abrasive jet machining makes use of an air abrasive jet with high velocity. to remove material from work piece Let’s take a look at the schematic diagram of abrasive jet machining. in this diagram we have a filter a compressor a pressure gauge, a pressure regulator, a mixing chamber an abrasive feeder, a vibrato,r another pressure gauge, nozzle, work piece mounted on a fixture. Now let us see the working of Abrasive jet machining uses dry air or gas the gas can either be nitrogen or carbon dioxide.
The gas or the dry air is filtered and compressed by passing it through a filter and compressor. A pressure gauge and pressure regulator are used to control the pressure and regulate the flow of the compressed air. Now the compressed air is then passed into the mixing chamber in this particular setup abrasive quantity is controlled by inducing vibration to the feeder Let’s have a closer look at it. The abrasive powder and the compressed air are thoroughly mixed in the chamber. Remind you that the abrasive quantity is controlled by inducing vibration to the feeder with the help of a vibrator.
working of abrasive jet machining
now The air abrasive mixture moves further to the nozzle. Where the nozzle imparts high velocity to the mixture. which is directed at the work piece surface Material removal occurs due to the erosive action of the jet of air pressure mixture impinging on the work piece surface Let’s talk about performance parameter in machining The performance parameter can be grouped into four major categories well try to understand it with the help of cause and effect diagram Performance parameters depend upon work material, nozzle abrasive and gas AJM works well for brittle materials Then nozzle .
the nozzle which is used to deliver the mixture the work piece should be. manufactured from such materials, which can withstand the erosive action of the aggressive particles and should be wear resistant Okay, a one such example is Tungsten carbide.. Now let’s talk about abrasive. Well the performance parameter also depends upon the impressive particle size their type strength composition and mass flow rate. And performance parameter also depends upon gas: the pressure of the gas, velocity of the gas and composition of gas.
There are few process parameters, which affect the machining process The first one is standoff distance Standoff distance is the distance between the tip of the nozzle and the work piece surface. There we go now Larger the stand of distance poorer is the quality and accuracy of the cut another process parameter is abrasive flow rate as abrasive flow rate increases the number of abrasive particles .
Cutting the work piece also increases thereby increasing the material removal rate M R R But as the number of abrasive particles increases the abrasive flow. velocity goes down therefore, reducing the MRR The another process parameter is nozzle pressure. Mixing ratio is another important process parameter. Which also influences MRR Mixing ratio is denoted by capital M Which can be represented as V dot a upon V dot G the dot over V represents flow rate therefore volume flow rate of abrasive particle is to volume flow rate of carrier. gas an increase in value of M increases MRR but a large value of M may decrease jet velocity and sometimes may block the nozzle