AJM Project Design And Analysis (1).pptx

AJM Project Design And Analysis

1. Presentation on : DESIGN AND FABRICATION OF “ABRASIVE JET MACHINE” UIET, CSJM University, Kanpur GUIDED BY – ER. Ramendra Singh Niranjan Sir

2. PRESENTED BY: ANUPAM SHARMA – (280) RISHABH PANDEY – (312) SHIVANSHU GUPTA – (320) ABHISHEK KUMAR – (266)

3. INTRODUCTION In Abrasive Jet Machining (AJM), abrasive particles are made to impinge on the work material at a high velocity. The jet of abrasive particles is carried by carrier gas or air. High velocity stream of abrasive is generated by converting the pressure energy of the carrier gas or air to its kinetic energy and hence high velocity jet. Nozzle directs the abrasive jet in a controlled manner onto the work material, so that the distance between the nozzle and the work piece and the impingement angle can be set desirably. High velocity abrasive particles remove the material by micro-cutting action as well as brittle fracture of the work material.

4. PROCESS In AJM, air is compressed in an air compressor and compressed air at a pressure of around 5-10 bar is used as the carrier gas. Gases like CO2 , N2 can also use. Generally oxygen is not used as a carrier gas. Carrier gas is first passed through a pressure regulator to obtain the desired working pressure. Gas is then passed through an air dryer to remove any residual water vapour . To remove any oil vapour or particulate contaminant the same is passed through a series of filters. Then the carrier gas enters a closed chamber known as the mixing chamber. Abrasive particles enter the chamber from a hopper through a metallic sieve.

5. AJM DIAGRAM

6. COMPONENTS OF AJM COMPRESSOR A Compressor is defined as a machine that is used for the supply of air or any other gases at an increased pressure. It compresses the gas to a pressure of 5-10 bar. A Compressor unit comprises of components like drier and filter to remove dust particles and moisture to avoid jamming or condensation during the process of compression. AIR FILTER AND DEHUMIDIFIER The Air Filter which is otherwise called the moisture separator or dehumidifier is required for separating the moisture and particulate from air. Atmospheric air always contains some water vapour in it. As the air with high velocity is blown from the nozzle there is an abrupt rise in pressure which converts water vapour into moisture. The moisture makes the abrasive particles to agglomerate and this clogs the outlet of the Nozzle. To avoid this clogging moisture separator should be used before abrasive particles are mixed with compressed air.

7. COMPONENTS OF AJM FLOW CONTROL VALVE Control the volume flow rate of compressed gas so as to maintain the mixing ratio. It is used to stop the excess flow of compressed air in the circuit PRESSURE GAUGE Instrument showing the pressure of the fluid in bar or psi

8. COMPONENTS OF AJM MIXING CHAMBER The high pressure air from the compressor is passed through air filter to remove any impurities. Then it is fed to the mixing chamber which has one inlet for the incoming compressed air and outlet for mixture of abrasive particles and air. The abrasive particles are introduced from the side so to form a cyclone to facilitate better mixing. The chamber is of cylindrical shape made up of mild steel. PIPING SYSTEM The piping systems are required for carrying the compressed air from the compressor to the mixing chamber and from the mixing chamber to the nozzle orifice via the filter regulator. It is required to maintain the pressure in the line without eroding the pipe. Here high pressure pneumatic pipe having 12 mm internal dia. is provided. This is used because of long life, light weight, durability and easy availability

9. COMPONENTS OF AJM AJM Nozzle AJM nozzle is usually made of tungsten carbide or sapphire ( usually life – 300 hours for sapphire , 20 to 30 hours for WC) which has resistance to wear. Nozzle is made of either circular or rectangular cross section and head can be head can be straight, or at a right angle. It is so designed that loss of pressure due to the bends, friction etc is minimum possible. With increase in wear of a nozzle, the divergence of jet stream increases resulting in more stray cutting and high inaccuracy.

10. Calculation for kinetic threshold energy Equation:- Properties of Borosillicate Glass :- Young’s modulus = E = 63 Gpa Poisson’s Ratio – 0.2 Frac ture Toughness(Kc)= 0.76 MPa   Vicker’s Hardenss (H) = 5.4 GPa

11. By putting all the values ,we got E= 514 KJ This is minimum particle kinetic energy due to the surface normal component of velocity at which the cracking initiate Experimental Values:- Abrasive Particle Used :- Al 2 O 3

12. Design calculation for mixing chamber Density of abrasive particles is 3 gm/cc. Assuming whole 500gm is stored in hopper. Cone volume will provide additional storage capacity, Volume of cylinder = mass of abrasive particles / density    

13. Available diameter and thickness values of steel tube are taken from catalogue Stress calculation for steel tubes with15 bar pressure and available dimensions. Hence, Where, P = Internal pressure, D = Internal diameter of cylinder J = Joint efficiency = 1  

14. Outer Dia.(mm) Thickness(t) (mm) Avg. Dia (mm) Stress (MPa) Length(cm) 101.6 5.74 96.86 12.52 3 114.3 6.02 108.28 13.49 2 101.6 4 97.6 20.41 2.5 73 5.16 67.84 9.86 5 88.9 5.49 83.41 11.39 3.5 All calculation is done in excel. Results show that maximum stress generated in all dimensions is 33.48 MPa . While minimum strength available in catalogue is 130 MPa . Thus it is safe design for any available dimension in catalogue.

15. Calculation for bolt diameter PA (CYCLINDER) = n A(bolt) P = PD 2 = Where, P = Pressure = 15 bar D = inside diameter of mixing chamber n = number of bolts d = diameter of bolt = stress = 25 MPa At n = 3, d bolt = 3 mm  

16. Calculating the Nozzle Flow Rate The orifice discharge coefficient (Cd) is defined as the ratio of the stream area to the hole area. An orifice coefficient of 1.0 describes the condition in which the stream fills the hole. Q = 28.9 x Cd x d 2 x (P) 1/2 here, Q = flow rate in gpm (gallons per minute) C d = coefficient of discharge, d = orifice diameter in mm P = optimum pressure in psi(Pound per sq. inch) 5 bar = 72.518 psi By considering the best suitable orifice diameter being 1 mm C d = 1 Q = 28.9*1*(1*10 -3 ) 2 *(72.518) 1/2 Q = 0.4 gpm .

17. Abrasives Abrasive density = 2.3 g/cm3 Glass hardness (Hv) = 30 GPa Glass fracture toughness = 2.5 MPa Glass stress flow = 5000 MPa Air Density – 1.3 Kg/m3 Velocity - 500 to 700 m/s Pressure – 1 to 10 bar Flow rate – 8 to 10 m3 /sec Abrasive Jet Velocity – 100 to 300 m/s Stand Off Distance – 05 to 15 mm Impingement Angle – 600 to 900 PROCESS PARAMETERS Nozzle Material – Sapphire Diameter – 0.2 to 0.8 mm Life – 300 hours for Sapphire Process Capability Material Removal Rate (MRR) – 0.015 cm3 /min Surface Finish – 0.25 microns to 1.25 microns Glass Thickness – 5 to 8 mm Pressure – 2 to 8 Kg/cm2

18. COMPONENTS OF AJM Abrasives Grain Sizes Application Aluminum oxide (Al2O3) 12, 20, 50 microns Good for cleaning, cutting and debarring Silicon carbide (SiC) 25, 40 microns Used for similar application but for hard material Glass beads 0.635 to 1.27 mm Gives matte finish Dolomite 66 Microns Etching and polishing Sodium bi carbonate 27 micros Cleaning, debarring, and cutting of soft material Light finishing below 50◦C

19. ADVANTAGES It is able to cut brittle, fragile or glass and heat sensitive material without damage. It is able to cut intricate shape or complex profile in hard or brittle materials. As the machining action is cool, so in this process, no heat is generated. No tool change required. High-quality surface finish. The surface of the work piece is cleaned automatically. Capital cost is low

20. DISADVANTAGES Very low material removal rate. Hence the application of AJM is limited. The process produces a taper cut always. In certain substances, abrasive particles might settle over the work piece. Nozzle life is less. It can’t be used machining soft materials. It can’t be used to drill blind holes.

21. APPLICATION Used in cutting slots, thin sections, drilling. It can be also used for Removal of oxide or corrosive layer from surface. It is sometimes used for cleaning and polishing of Teflon and plastics components. It is used for paint removal. It is used mainly in textile and leather industries. It is used for ceramic abrading and glass frosting.

22. COST ESTIMATION COMPONENTS PRICE AIR COMPRESSOR ₹8000 AIR FILTER (FRL UNIT) ₹1500 PRESSURE GAUGE ₹500 MIXING CHAMBER ₹1800 ABRASIVES ₹500 FLOW CONTROL VALVES ₹500 NOZZLE ₹2000 PIPING SYSTEM ₹500 BENCH VICE ₹500 MILD STEEL FRAME ₹2000 GLASS ₹500 TOTAL ESTIMATION COST ₹18,300

23. REFERENCES [1] International Journal of Engineering Research and General Science Volume 3, Issue 3, May-June, 2015 ISSN 2091-2730 1052 www.ijergs.org Design Of Abrasive Jet Machine Harshavardhan Ronge, Swapnil Wagh , Rohit Shinde [2] Research and Applications of Thermal Engineering Volume 4 Issue 2 Design and Fabrication of Economically Feasible Abrasive Jet Machine Suyash Lengule1* , Shakti Sarkar2 , Aditya Mandwe3 , Ravi Pandey4 , Vimal Sontake5 [3] International Research Journal of Engineering and Technology (IRJET) Volume: 08 Issue 02 Modeling and Fabrication of Abrasive Jet Machining Shantanu Garad [4] https://themechanicalengineering.com/abrasive-jet-machining/ [5] https://www.ijert.org/process-characteristics-of-abrasive-jet-machining

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