presentation of abrasive jet machining 120107073203 phpapp02

8/11/2019 Presentation of Abrasive Jet Machining 120107073203 Phpapp02

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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 .


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COMPONENTSOFABRASIVEJET

MACHINING

Abrasive delivery system

Control system

Pump

Nozzle

Mixing tube

Motion system


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1 ABRASIVE DELIVERY SYSTEM

Auto abrasive delivery system has the capability

of storing abrasive delivery the abrasive to

the bucket Its works auto programming

system by help of once measuring record no

adjustment or fine tuning system . High sensitive

sensor gives extremely reliable repeatable .


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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 .


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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 .


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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 .


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FIG OF NOZZLE


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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 .


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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


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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 .


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FIG SCHEMATIC DIAGRAM OF AJM


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AJM FEATURES

There are main features of AJM

Obtainable tolerances

Material to machine

Material thickness

Accuracy of table

Stability of table

Control abrasive jet


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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


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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 .


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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


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DISADVANTAGES

Low metal removal rate

Due to stay cutting accuracy is affected

Abrasive powder cannot be reused

Tapper is also a problem


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CONCLUSION

The better performance , and the applications

represented above statements confirm that

ABRASIVE JET MACHINING is continue to

expand .

The new softwares used to minimize time and

investments , there by making it possible for

more manufacturers of precision parts to

install AJM centers .

presentation of abrasive jet machining 120107073203 phpapp02

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