Abrasive jet machining (AJM) is one of the modern machining processes where high velocity jet of abrasives mixed with dehumidified pressurized gas is made. PDF | Abrasive jet machining (AJM) is a manufacturing technology based on erosion localization and intensification. AJM has a progressively. PDF | As Abrasive jet machining (AJM) is similar to sand blasting and effectively removes hard and brittle materials. AJM has been applied to rough working.
|Published (Last):||11 June 2006|
|PDF File Size:||12.7 Mb|
|ePub File Size:||7.95 Mb|
|Price:||Free* [*Free Regsitration Required]|
Common applications of abrasive jet machining process are provided below. Abrasive jet machining AJM is one of the advanced machining processes mechanical energy based where a high velocity jet of abrasives is utilized to remove material from work surface by impact erosion. A compressor is used to elevate pressure of the carrier gas as high as 20bar ; abrasive grits are mixed with it in a mixing chamber as per mixing ratioand a nozzle is used to convert pressure energy into kinetic energy in the form of high velocity jet.
Cutting and drilling hole —AJM can also be utilized for cutting various shapes as well as for drilling holes. The surface machined can have good finish by controlling the grain size mainly.
Abrasive Jet Machining (AJM) «
Another disadvantage is that the process produces a tapered cut. As discussed earlier, shape, size, strength, material and flow rate of abrasive can influence machining performance.
Typical engraving applications for AJM includes— Incising person name or company name on nameplate Incising logo, serial number and other relevant information on product Incising registration number for vehicles Making decorative objects intricate styles cannot be obtained by AJM Ceramic abrading and glass frosting Non-corrosive abrading of ceramic materials can be carried out by abrasive jet machining AJM.
Engraving Engraving is the process of incising pattern, letter, art or design on a solid surface for decorative or artistic or formal purposes. However, if work material is too soft, AJM should be avoided.
As an isentropic steady flow device, nozzle converts hydraulic energy pressure of the gas-abrasive mixture to the kinetic energy and thus high velocity jet is obtained. Among various gases, air is commonly used in AJM as it is abundantly available at free of cost. AJM machines are usually self-contained bench-top units. In AJM, usually circular hopper with gradual compression is employed for continuously supplying fresh abrasive to the mixing chamber.
The harder is the abrasive with respect to work surface hardness, the larger will be the volume removal rate. Moreover, increased gas flow rate gives the provision for utilizing higher abrasive flow rate, which can improve productivity.
Abrasive-jet Machining (AJM)
List of factors that affect abrasive jet machining performance. Deburring —Abrasive jet machining is one of the efficient methods for deburring process for removal of burr of milled features and drilled holes, especially when work material is hard. Engraving —As an alternative to laser beam machining, abrasive jet machining can also be applied for incising purposes irrespective of chemical and electrical properties of work material.
However, variation in size in the entire volume should be low otherwise estimation or assessment will not be accurate.
Usually tungsten carbide WC or sapphire nozzles are used in industrial applications. The distance of the nozzle from the workpiece affects the size of the machined area and the rate of material removal.
Effects of process parameters on AJM performance are discussed below. Indefinite increase in MRR is not practically feasible because of limited capability of equipment and accessories. Abrasive jet machining AJM is one of the modern machining processes where high velocity jet of abrasives mixed with dehumidified pressurized gas is made to impinge the work surface, which in turn removes material by mechanical erosion.
The basic unit is schematically shown in following Figure.
There are some allowances which are responsible for the difference in the dimensions of the casting and the pattern The operating elements in AJM are abrasive, carrier gas and the nozzle as schematically shown in the following Figure. Abrasive jet machining can be applied for metal surface cleaning like removing oxide or corrosive layer from hard surface. AJM can be advantageously used for cleaning metallic or ceramic surfaces substrate must be hard.
The main advantages are its flexibility, low heat production, and ability to machine hard and brittle materials. Common uses include cutting heat-sensitive, brittle, thin, or hard materials. Effects of carrier gas on abrasive jet machining performance. Hopper is used for machning the abrasive powder. Compressed air is then passed into the mixing chamber. Nozzle also directs high velocity jet towards work surface from a specific distance called SOD and at a particular predefined angle, called impingement angle.
Also a good appearance may not be obtained if engraving is carried out by AJM. AJM can also be used for various trimming applications in molding and forging. It is to be noted that, irrespective of the purpose, abrasive jet machining AJM is beneficial only for hard and brittle materials. This gives easy, accurate and precise control and is suitable for cutting intricate profiles and contours.
It compresses the carrier gas to a pressure of 15 — 20bar. It is evident that the SOD changes the abrasive particles spreads i. It forces the abrasive jet over the workpiece. I am a mechanical engineer with a passion for technical stuff.
It also facilitates accurate estimation of productivity, delivery time as well as production cost. It filters the gas before entering the compressor and mixing xbrasive. It consists of gas supply system compressorfilter, pressure regulator, mixing chamber, nozzle assembly and the work holding device.