WHAT IS ABRASIVE JET MACHINING ? It is the material removal process where the material is removed by high velocity stream of air/gas or water and abrasive mixture . An abrasive is small, hard particle having sharp edges and an irregular shape . High velocity jet is aimed at a surface under controller condition .
COMPONENTS OF ABRASIVE JETMACHINING Abrasivedelivery system Control system Pump Nozzle Mixing tube Motion system
1. ABRASIVE DELIVERY SYSTEMAuto abrasive delivery system has the capability of storing abrasive & delivery the abrasive to the bucket . It’s works auto programming system by help of once measuring record & no adjustment or fine tuning system . High sensitive sensor gives extremely reliable & repeatable .
2.CONTROL SYSTEM The control algorithm that computes exactly how the feed rate should vary for a given geometry in a given material to make a precise part . The algorithm actually determines desired variation in the feed rate & the tool path to provide an extremely smooth feed rate .
3.PUMP Crankshaft & intensifier pump are mainly use in the abrasive jet machine . The intensifier pump was the only pump capable of reliably creating pressures high . Crankshaft pumps are more efficient than intensifier pumps because they do not require a power robbing hydraulic system ultra high pressure & more stroke per minute .
4.NOZZLE All abrasive jet systems use the same basic two stage nozzle . First , water passes through a small diameter jewel orifice to form a narrow jet . The abrasive particles are accelerated by the moving stream of water & they pass into a long hollow cylindrical ceramic mixing tube. Generally two type of nozzle use , right angle head & straight head .
5. MIXING TUBE The mixing tube is where the abrasive mixes with the high pressure water . The mixing tube should be replaced when tolerances drop below acceptable levels . For maximum accuracy , replace the mixing tube more frequently .
6.MOTION SYSTEM In order to make precision parts , an abrasive jet system must have a precision x-y table and motion control system . Tables fall into three general categories . Floor-mounted gantry systems Integrated table/gantry systems Floor-mounted cantilever systems
WORKING PROCESS High pressure water starts at the pump , and is delivered through special high pressure plumbing to the nozzle . At the nozzle , abrasive is introduced & as the abrasive/water mixture exits , cutting is performed . Once the jet has exited the nozzle , the energy is dissipated into the catch tank , which is usually full of water & debris from previous cut .
AJM FEATURES There are main features of AJM Obtainable tolerances Material to machine Material thickness Accuracy of table Stability of table Control abrasive jet
MACHINE ASPECTS Around curves Inside corner Feed rate Acceleration Nozzle focus Speed cutting Pump pressure Hardness & thickness Software controlling the motion Power at the nozzle
TYPES OF ABRASIVE MATERIALS Different types of abrasive are used in abrasive jet machining like garnet , aluminum oxide , olivine , silica sand , silicon carbide ,etc . Virtually any material can be cut by using abrasive jet machining method , i.e harder materials like titanium to steel. Abrasive particles must be hard ,high toughness, irregular in shape & edges should be sharp .
ADVANTAGES Extremely fast setup & programming No start hole required There is only one tool Low capital cost Less vibration No heat generated in work piece Environmentally friendly
DISADVANTAGES Low metal removal rate Due to stay cutting accuracy is affected Abrasive powder cannot be reused Tapper is also a problem
CONCLUSION The better performance , and the applications represented above statements confirm that ABRASIVE JET MACHINING is continue to expand . The new software’s used to minimize time and investments , there by making it possible for more manufacturers of precision parts to install AJM centers .