Design and Fabrication Of Abrasive Jet Machine Report Download :
Introduction To AJM:
Abrasive Jet Machining (AJM) is Non conventional machining the removal of material from a workpiece by the application of a high speed stream of abrasive particles carried in gas medium from a nozzle. The AJM process differs from conventional sand blasting in that the abrasive is much finer and the process parameters and cutting action are carefully controlled. The process is used chiefly to cut intricate shapes in hard and brittle materials which are sensitive to heat and have a tendency to chip easily. The process is also used for debarring and cleaning operations. AJM is inherently free from chatter and vibration problems. The cutting action is cool because the carrier gas serves as a coolant.
Machine Parts and Setup :
The major components are:
1. Air compressor.
2. Air filter.
4. Pressure Gauge.
5. Pressure Regulator.
6. Vibrator or Mixer.
8. Arrangement to hold the work piece.
Different variables in Abrasive Jet Machine:
The variables that influence the rate of metal removal and accuracy of machining in this process is:
1. Carrier gas
2. Types of abrasive
3. Size of abrasive grain
4. Velocity of abrasive jet
5. Flow rate of abrasive
6. Work material
7. Geometry, composition and material of nozzle
8. Nozzle work distance (stand off distance)
1. Low capital cost
2. Ability to cut intricate holes shape in materials of any hardness.
3. Ability to cut heat sensitive material without damage.
4. As no heat is generated in the process, no change in micro-structure
1. Material removal rate is low and hence its application is limited.
2. Embedding of the abrasive in the work piece surface may occur while machining softer
3. The abrasive material may accumulate at nozzle and fail the process if moisture is present in the air.
4. It cannot be used to drill blind holes.
5. Occasional plugging of mixing tube: Usually caused by dirt or large particles in abrasive.
6. Wear, misalignment, and damage to the nozzle.