- Email: [email protected]
Experimental study on surface roughness by using abrasive jet machine
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Experimental study on surface roughness by using abrasive jet machine A.K. Chaitanya, D. Kishore Babu, K.V.N. Girish Kumar PSCMR Engineering College, Kothapeta, Vijayawada, India
a r t i c l e
i n f o
Article history: Received 13 May 2019 Received in revised form 25 May 2019 Accepted 28 May 2019 Available online xxxx Keywords: Abrasive jet machine (AJM) Material removal rate (MRR) Surface roughness (Ra) Nontraditional machining (NTM) Silicon carbide (SIC)
a b s t r a c t A machining operation is basically termed a material removal process, where material is removed in the form of chips. In a machining operation, the output parameter is achieved by controlling various input parameters. Abrasive jet machining process is an unconventional machining process. In this process a high velocity of abrasive particles directed to hit on the work piece to remove the material. Abrasive jet machining process is especially useful to perform operations on brittle materials, ductile materials. This process is mainly used for producing intricate shapes and also perform deburring and cleaning operations. Abrasive materials like aluminum oxide, silicon carbide etc. In this paper measuring the surface roughness on ductile materials like mild steel and also studying how aluminum oxide, silicon carbide abrasive particles effected on work piece. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Materials, Manufacturing & Energy Systems.
1. Introduction: Abrasive jet machining (AJM) is a processing nontraditional machine which operators on no physical contact between tool and workpiece so there is no thermal stresses and shocks developed. AJM is applied for so many applications like cutting, cleaning, polishing, deburring, drilling and finishing operations. In abrasive jet machining abrasive particles are made to impinge on work material at high velocity. In Abrasive Jet Machining, a centered stream of abrasive particles, carried by air mass air or gas is formed to hit the surface through a nozzle and work material is removed by erosion by fast abrasive particles. The AJM differs from sandblasting. In AJM the abrasive is far finer and therefore the method parameters and cutting action area unit fastidiously controlled. Sand blasting is an act of propelling very fine bits of material at high velocity to clean or etch a surface. n AJM, a cantered steam of abrasive particles carried by high gas is employed. Uniform particles of sand, steel grit, copper slag, walnut shells, and powdered abrasives are used. Silicon inorganic compound, aluminum oxide, glass beads, dolomite, sodium bicarbonate are used as abrasives. In sand blasting abrasives area unit sprayed everywhere sometimes for improvement surfaces from corrosion, paints, glues and other contaminants. AJM is not only used for cleaning but also for cutting, deburring, etc. AJM is a well-controlled process compared to sand blasting. E-mail address: [email protected] (A.K. Chaitanya)
AJM is especially wont to cut tortuous shapes in laborious and brittle materials that area unit sensitive to heat and chip simply. The process is additionally used for deburring and improvement operations. AJM is inherently free from chatter and vibration issues. The cutting action is cool because of the carrier gas is a fluid. A workshop while not a water jet is sort of a carpenter while not a hammer ultimately. Sure, the carpenter can use the back of his crow bar to hammer in nails, but there is a better way. It is necessary to grasp that abrasive jets don’t seem to be constant factor because the water jet though they’re nearly constant. Water Jet technology has been around since the early 1970s or so, and abrasive jets extended the concept about ten years later. Both technologies use the principle of pressuring water to very high and allowing the water to escape through opening typically called the orifice or jewel. Jets use the beam of water exiting the passage to chop soft stuffs like candy bars but are not effective for cutting harder materials. The recess water is usually controlled between 20,000 and 60,000 Pounds per Square inch (PSI). 1.1. Classification of non-traditional machining processes: To classify Non-Traditional Machining Processes (NTM), one needs to understand and analyze the differences and similar characteristics between conventional machining processes and NTM processes. Conventional Machining Processes largely take away material within the kind of chips by applying forces on the work material with a wedge formed cutlery that’s tougher than the work
https://doi.org/10.1016/j.matpr.2019.05.343 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Materials, Manufacturing & Energy Systems.
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
2
A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx
material under machining condition. Such forces induce plastic deformation among the work piece resulting in shear deformation on the shear plane and chip formation. Thus the key characteristics of typical machining are: typically, microscopical chip formation by shear deformation. Material removal takes place because of application of cutting forces – energy domain will be classified as mechanical. Material removal could occur with chip formation no chip formation may occur. For example, in AJM, chips are of microscopic size and in case of Electrochemical machining material removal occurs due to electrochemical dissolution at atomic level. In NTM, there might not be a physical tool gift. For example, in optical device jet machining, machining is carried out by laser beam. However, in chemical science machining there’s a physical tool that’s pretty much needed for machining. In NTM, the tool needn’t be tougher than the work piece material. For example, in EDM, copper is employed because the tool material to machine hardened steels. Mostly NTM processes don’t essentially use energy to supply material removal. They use different energy domains to provide machining. For example, in USM, AJM, WJM energy is employed to machine material, whereas in EW chemical science dissolution constitutes material removal. Thus, classification of NTM processes is meted out reckoning on the character of energy used for material removal. The broad classification is given as follows: Mechanical Processes Abrasive Jet Machining (AJM) inaudible Machining (USM) Water Jet Machining (WJM) Abrasive Water Jet Machining (AWJM). Electro chemical Processes Electrochemical Machining (ECM) Electro Chemical Grinding (ECG) Electro Jet Drilling (EJD) ElectroThermal Processes Electro-discharge machining (EDM) - optical maser Jet Machining (LJM) ray Machining (EBM) Chemical Processes Chemical edge (CHM) chemical science edge (PCM) etc. 1.2. Need for non-traditional mahining processes: Conventional machining sufficed the necessity of the industries over the decades. But new exotic work materials in addition as innovative geometric style of product and parts were putt ton of pressure on capabilities of standard machining processes to manufacture the components with desired tolerances economically. This LED to the event and institution of NTM processes within the trade as economical and economic alternatives to standard ones. With development within the NTM processes, presently there square measure usually the primary alternative and not another to standard processes sure enough technical needs. The following examples are provided where NTM processes are preferred over the intricate shaped blind hole – e.g. square hole of 15 mm 15 mm with a depth of 30 mm 1.3. Definition of AJM In Abrasive Jet Machining (AJM), abrasive particles are created to strike the work material at a high rate. The jet of abrasive particles is carried by carrier gas or air. The high rate stream of abrasive is generated by changing the pressure energy of the carrier gas or air to its K.E. and thus high rate jet. The nozzle directs the abrasive jet during a controlled manner onto the work material, so the space between the nozzle and therefore the work piece and therefore the impingement angle can be set desirably. The high-speed abrasive particles take away the fabric by micro- cutting action in addition as brittle fracture of the work material. Schematically shows material removal process (Fig. 1). AJM is different from standard shot or sand blasting, as in AJM, finer abrasive grits are used and the parameters can be controlled more effectively providing better control over product quality. In AJM, generally, the abrasive particles of around fifty lm grit size
Fig. 1. Schematic diagram of abrasive jet machine.
would collide with the work material at speed of two hundred m/s from a nozzle of I.D. of 0.5 metric linear unit with a standoff distance of around a pair of metric linear unit. The kinetic energy of the abrasive particles would be enough to provide material removal due to brittle fracture of the work piece or even micro cutting by abrasives. 1.3.1. Equipment In AJM, air is compressed in an air compressor and compressed air at a pressure of around 5 bar is used as the carrier gas as shown in Fig.9.1.4 conjointly shows the opposite major components of the AJM system. Gases like greenhouse gas, N2 also can be used as carrier gas which can directly be issued from a gas cylinder. Generally, gas isn’t used as a carrier gas. First older a pressure regulator to get the required operating pressure. The gas is then well-versed true gone through had undergone saw felt responded to suffer an air drier to get rid of any residual water vapor. To remove any oil vapour or particulate contamination constant is older a series of filters. Then the carrier gas enters a closed chamber referred to as the blending chamber. The abrasive particles enter the chamber from a hopper through a gilded sieve. The sieve is consistently vibrated by Associate in nursing magnetism shaker. The mass rate of flow of abrasive (15 gm/min) getting into the chamber depends on the amplitude of vibration of the sieve and its frequency. The abrasive particles are then carried by the carrier gas to the machining chamber via an electromagnetic on-off valve. The machining enclosure is crucial to contain the abrasive and machined particles in an exceedingly safe and eco-friendly manner. The machining is carried out as high velocity (200 m/s) abrasive particles are issued from the nozzle onto a work piece traversing under the jet. 1.4. Abrasive jet machining operations Surface finishing is a broad range of industrial process that alter the surface of a manufactured item to achieve a certain property. Finishing processes may be employed to: improve appearance, adhesion or wettability, solder ability, corrosion resistance, tarnish resistance, chemical resistance, wear resistance, hardness, modify electrical conductivity, remove burrs and other surface flaws, and control the surface friction. In restricted cases a number of these techniques may be wont to restore original dimensions to salvage or repair associate degree item. An unfinished surface is often called mill finish. Polishing associate degreed buffing area unit finishing processes for smoothing a piece piece’s surface victimization
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
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A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx
an abrasive and a piece wheel or a animal skin strop. Technically sharpening refers to processes that use associate degree abrasive that’s affixed to the work wheel, whereas buffing uses a loose abrasive applied to the work wheel. Polishing may be a additional aggressive method whereas buffing is a smaller amount harsh, which leads to a smoother, brighter finish. A common thought is that a cultured surface contains a mirror bright end, but most mirror bright finishes are actually buffed. 1.5. Selection of abrasives Aluminum oxide (Al2O3) silicon carbide (SiC) glass beads, crushed glass and sodium bicarbonate are some of abrasives used in AJM. Selection of abrasives depends on MRR, kind of work material, and machining accuracy. Table offers classification of abrasives and its applications. Tabular column for various Abrasives: (Table 1) Aluminum oxide: Aluminum oxide is employed for its hardness and strength. It is wide used as AN abrasive, as well as a far less costly substitute for industrial diamond. Many types of sandpaper use aluminum oxide crystals. In addition, its low heat retention and low heat build it wide utilized in grinding operations, significantly cut-off tools. As the powdery abrasive mineral aloxite, it’s a serious element, together with oxide, of the cue tip ‘‘chalk” utilized in table game. Aluminum oxide powder is employed in some CD/DVD sprucing and scratch-repair kits. Its sprucing qualities also are behind its use in dentifrice. In restricted cases a number of these techniques is wont to restore original dimensions to salvage or repair Associate in Nursing item. An unfinished surface is often called mill finish. Surface finishing processes is categorized by however they have an effect on the work piece: Removing or reshaping finishing Adding or altering finishing Mechanical processes might also be categorized along due to similarities the ultimate surface end.
diamond resolution is utilized in the sharpening method. Polishing chrome steel may increase the hygienical advantages of chrome steel. The removal of chemical reaction (tarnish) from metal objects square measure accomplished employing a metal polish or tarnish remover; this is often conjointly known as sprucing. To prevent additional unwanted reaction, polished metal surfaces may be coated with wax, oil, or lacquer. This is of specific concern for copper alloy product like brass and bronze. Mechanical properties: The strength of polished product is often more than their rougher counterpart due to the removal of stress concentrations gift within the rough surface. They take the shape of corners and alternative defects that enlarge the native stress on the far side the inherent strength of the fabric. Polishing with terribly fine abrasive differs physically from coarser abrasion, in this material is removed on a molecular level, so the speed is correlative to the boiling purpose rather than to the freezing point of the fabric being polished.
1.7. Selection of abrasives Common Abrasive Materials Synthetic Diamond Cubic Boron Nitride (CBN) Aluminum Oxide Silicon Carbide (Sic)
1.7.1. Aluminum oxide Aluminum oxide is used for its hardness and strength. It is wide used as associate abrasive, as well as a far more cost-effective substitute for industrial diamond (Fig. 2). Many types of sandpaper use aluminum oxide crystals. In addition, its low heat retention and low heat energy create it wide employed in grinding operations, notably cut-off tools. As the powdery Alumina is employed to manufacture tiles, that area unit connected within powdery fuel lines, and flue gas ducting on coal dismissed power stations to shield high wear areas. They are not suitable for areas with high impact forces as these tiles are brittle and susceptible to breakage.
1.6. Polishing Polishing associated buffing square measure finishing processes for smoothing a piece piece’s surface victimization an abrasive and a piece wheel or an animal skin strop. Technically sharpening refers to processes that use associate abrasive that’s affixed to the work wheel, whereas buffing uses a loose abrasive applied to the work wheel. Polishing could be a additional aggressive method whereas buffing is a smaller amount harsh, which leads to a smoother, brighter finish. A common idea is that a cultured surface incorporates a mirror bright end, however most mirror bright finishes are buffed. Polishing is commonly accustomed enhance the looks of associate item, prevent contamination of instruments, remove oxidation, create a reflective surface, or prevent corrosion in pipes. In metallographic and science, polishing is used to create a flat, defect-free surface for examination of a metal’s microstructure under a microscope. Silicon-based sharpening pads or a
Fig. 2. Aluminum oxide.
Table 1 Details of various abrasives. Abrasives
Grain sizes
Application
Aluminum oxide (Al2O3) Silicon carbide (SiC) Glass Beads Dolomite Sodium Bicarbonate
12,20,50 mm 25,50 mm 0.635–1.25 mm 200 mesh 27 mm
Good for cleaning, cutting, deburring Used for similar applications but for hard materials Gives matte finish Etching and polishing Cleaning, deburring and cutting of soft material. Light finishing below 500 °C
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
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A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx
1.7.2. Silicon carbide Silicon Carbide (Sic) is Associate in Nursing inorganic material having mechanical, thermal, electrical and chemical properties, because of that it’s wide employed in developed industries. However, the useful properties of assault ceramic like high hardness, high strength, wear resistance, extreme breakableness and chemical stability create assault machining troublesome and dear through (Fig. 3). Conventional and non-conventional machining methods. Hence, in gift study a summary of previous work on attack ceramic is meted out. Many researchers tried varied strategies for machining of set ceramic from that electro discharge machining method, optical maser machining method, grinding method and diamond turning machining method is that the most applied methods. The theoretical, experimental and simulation studies are thought of for getting important results. The researchers in the main centered on Material removal rate, surface roughness, surface end and power wear rate.
Fig. 5. Nozzle.
2. Experimental setup 2.1. Gas propulsion system:(air compressor) The main purpose of gas system is to supply clean and dry, high speed air or gas for machining. Mostly air, carbon dioxide, Nitrogen etc. are used as gas in gas propulsion system. This system consists, compressor, air filter and drier (Fig. 4). 2.2. Abrasive feeder As the name implies, abrasive feeder is employed to produce abrasive particles in mixture chamber. It is fed through a sieve that
Fig. 6. Plastic pipes for the flow of abrasives.
vibrates at 50–60 cps and mixture magnitude relation is management by the vibration of the sieve and its amplitude. 2.3. Nozzle To direct the abrasive particle on work piece cutting nozzles ar used. They are usually made by tungsten carbide. They are obtainable in each circular and sq. cross section. Its life is sometimes low regarding thirty hours for metal inorganic compound (Fig. 5) 2.4. Machining chamber It is fully closed air tight chamber which control the concentration of abrasive particle around work piece. This is equipped with a vacuum dirt collector that collect used abrasive particle and removed material from mixture chamber. 2.5. Filter It filters the gas before coming into the mechanical device and combining chamber. Hopper: Hopper is employed for feeding the abrasive powder. 2.6. Pressure gauges and flow regulators
Fig. 3. Silicon carbide.
They are accustomed management the pressure and regulate the rate of abrasive jet.
Fig. 4. Gas propulsion system (Air compressor).
Fig. 7. Mitutoyo surftest sj-210.
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
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A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx Table 2 Ra values in micrometers. Material
Trail-1 mm
Trail-2 mm
Trail-3 mm
Surface roughness values Micrometers (Ra)
Machined with aluminum oxide Specimen 1 Machined with aluminum oxide Specimen 2 Machined with silicon carbide Specimen 1 Machined with Silicon carbide Specimen 2 Un machined piece
0.011 0.012 0.014 0.015 0.018
0.012 0.013 0.013 0.014 0.017
0.013 0.012 0.012 0.013 0.018
0.012 0.012 0.013 0.014 0.018
2.7. Vibrator
4.4. Surface roughness graph for un machined piece
It is provided below the mixing chamber. It controls the abrasive powder feed rate within the mixture chamber (Fig. 6). 3. Experimental analysis 3.1. Roughness measurement Roughness measurement has been done using a portable MITUTOYO SURFTEST SJ-210, Shown in Fig. The instrument could be a moveable, self-contained instrument for the measurement of surface texture. The parameter evaluations are microprocessor based. The measuring results square measure displayed on associate LCD screen and may be output to associate ex gratia printer or another pc for any analysis. It is equipped with a diamond stylus having a tip radius five lm. The measure stroke continually starts from the intense outward position. At the top of the measuring the pickup returns to the position prepared for following measuring. The selection of cut-off length determines the traverse length (Fig. 7). 4. Results 4.1. Tabular column for Ra values in micrometers Table 2 4.2. Surface roughness graph for aluminum oxide machined piece
5. Conclusion 1) For higher precision work higher pressure and lower standoff distance are adopted to attain a higher accuracy and penetration rate for AJM. 2) The higher standoff distance is preferable where material removal is prime importance. 3) MRR increase with an increase in abrasive jet flow rate, mixing ratio, internal pressure, standoff distance under certain condition. 4) By using aluminum oxide abrasive particles getting better surface finishing compared with silicon carbide abrasive particles.
Further reading
4.3. Surface roughness graph for silicon carbide machined piece
[1] G. Boothroyd, W.A. Knight, Fundamentals of Machining and Machine Tools, Second Edition., Marcel Thomas Decker Iraqi National Congress, New York, 1989. [2] D.D. Charisis, S.O. Koutayas, P. Kamposiora, A. Doukoudakis, Spectrometric analysis of the influence of various backgrounds on the color of glass-infiltrated ceramic veneers, Eur J Esther Dent. 1 (2006) 142–156. [3] B.C. Brosheer, ‘‘How Smooth is Smooth? Part-I, Specification and Evaluation of Machined Finishes”, yank journeyman, McGraw-Hill business firm, 1948, pp. 97–112. [4] CIE 1971: International Commission on Illumination. Colorimeter: official recommendations of the International Commission on Illumination. Publication CIE No.15 (E-1.3.1), Bureau Central First State la CIE, Paris, 1971. [5] M. Gall, W.R. Borg, J.P. Gall, Instructional Analysis, sixth ed., Longman, New York, 1996. [6] Terminology and Parameters, Hummel America, 30, Peter Court, New Britain, CT, 1988. [7] Stavridakis, M.M., Papazoglou, E., Seghi, R.R., Johnston, W.M., Brantley, W.A. Effect of various high-palladium metal-ceramic alloys on the color of opaque and dentin ceramic ware. [8] Jagadeesha T, Assistant professor, Abrasive jet machining, national institute of technology, Calicut. [9] Jigar Kumar P. Patel, Dr. K.V. Modi, Development of abrasive jet machine. [10] Prof. V.K. Jain, Mechanical engineering department I.I.T. Kanpur-208016, Micro machining process. [11] Mistri Ankit N, UG Student, Department of mechanical engineering, Chhotubhai Gopal Bhai institute of technology, Bardoli.
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Experimental study on surface roughness by using abrasive jet machine A.K. Chaitanya, D. Kishore Babu, K.V.N. Girish Kumar PSCMR Engineering College, Kothapeta, Vijayawada, India
a r t i c l e
i n f o
Article history: Received 13 May 2019 Received in revised form 25 May 2019 Accepted 28 May 2019 Available online xxxx Keywords: Abrasive jet machine (AJM) Material removal rate (MRR) Surface roughness (Ra) Nontraditional machining (NTM) Silicon carbide (SIC)
a b s t r a c t A machining operation is basically termed a material removal process, where material is removed in the form of chips. In a machining operation, the output parameter is achieved by controlling various input parameters. Abrasive jet machining process is an unconventional machining process. In this process a high velocity of abrasive particles directed to hit on the work piece to remove the material. Abrasive jet machining process is especially useful to perform operations on brittle materials, ductile materials. This process is mainly used for producing intricate shapes and also perform deburring and cleaning operations. Abrasive materials like aluminum oxide, silicon carbide etc. In this paper measuring the surface roughness on ductile materials like mild steel and also studying how aluminum oxide, silicon carbide abrasive particles effected on work piece. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Materials, Manufacturing & Energy Systems.
1. Introduction: Abrasive jet machining (AJM) is a processing nontraditional machine which operators on no physical contact between tool and workpiece so there is no thermal stresses and shocks developed. AJM is applied for so many applications like cutting, cleaning, polishing, deburring, drilling and finishing operations. In abrasive jet machining abrasive particles are made to impinge on work material at high velocity. In Abrasive Jet Machining, a centered stream of abrasive particles, carried by air mass air or gas is formed to hit the surface through a nozzle and work material is removed by erosion by fast abrasive particles. The AJM differs from sandblasting. In AJM the abrasive is far finer and therefore the method parameters and cutting action area unit fastidiously controlled. Sand blasting is an act of propelling very fine bits of material at high velocity to clean or etch a surface. n AJM, a cantered steam of abrasive particles carried by high gas is employed. Uniform particles of sand, steel grit, copper slag, walnut shells, and powdered abrasives are used. Silicon inorganic compound, aluminum oxide, glass beads, dolomite, sodium bicarbonate are used as abrasives. In sand blasting abrasives area unit sprayed everywhere sometimes for improvement surfaces from corrosion, paints, glues and other contaminants. AJM is not only used for cleaning but also for cutting, deburring, etc. AJM is a well-controlled process compared to sand blasting. E-mail address: [email protected] (A.K. Chaitanya)
AJM is especially wont to cut tortuous shapes in laborious and brittle materials that area unit sensitive to heat and chip simply. The process is additionally used for deburring and improvement operations. AJM is inherently free from chatter and vibration issues. The cutting action is cool because of the carrier gas is a fluid. A workshop while not a water jet is sort of a carpenter while not a hammer ultimately. Sure, the carpenter can use the back of his crow bar to hammer in nails, but there is a better way. It is necessary to grasp that abrasive jets don’t seem to be constant factor because the water jet though they’re nearly constant. Water Jet technology has been around since the early 1970s or so, and abrasive jets extended the concept about ten years later. Both technologies use the principle of pressuring water to very high and allowing the water to escape through opening typically called the orifice or jewel. Jets use the beam of water exiting the passage to chop soft stuffs like candy bars but are not effective for cutting harder materials. The recess water is usually controlled between 20,000 and 60,000 Pounds per Square inch (PSI). 1.1. Classification of non-traditional machining processes: To classify Non-Traditional Machining Processes (NTM), one needs to understand and analyze the differences and similar characteristics between conventional machining processes and NTM processes. Conventional Machining Processes largely take away material within the kind of chips by applying forces on the work material with a wedge formed cutlery that’s tougher than the work
https://doi.org/10.1016/j.matpr.2019.05.343 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Materials, Manufacturing & Energy Systems.
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
2
A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx
material under machining condition. Such forces induce plastic deformation among the work piece resulting in shear deformation on the shear plane and chip formation. Thus the key characteristics of typical machining are: typically, microscopical chip formation by shear deformation. Material removal takes place because of application of cutting forces – energy domain will be classified as mechanical. Material removal could occur with chip formation no chip formation may occur. For example, in AJM, chips are of microscopic size and in case of Electrochemical machining material removal occurs due to electrochemical dissolution at atomic level. In NTM, there might not be a physical tool gift. For example, in optical device jet machining, machining is carried out by laser beam. However, in chemical science machining there’s a physical tool that’s pretty much needed for machining. In NTM, the tool needn’t be tougher than the work piece material. For example, in EDM, copper is employed because the tool material to machine hardened steels. Mostly NTM processes don’t essentially use energy to supply material removal. They use different energy domains to provide machining. For example, in USM, AJM, WJM energy is employed to machine material, whereas in EW chemical science dissolution constitutes material removal. Thus, classification of NTM processes is meted out reckoning on the character of energy used for material removal. The broad classification is given as follows: Mechanical Processes Abrasive Jet Machining (AJM) inaudible Machining (USM) Water Jet Machining (WJM) Abrasive Water Jet Machining (AWJM). Electro chemical Processes Electrochemical Machining (ECM) Electro Chemical Grinding (ECG) Electro Jet Drilling (EJD) ElectroThermal Processes Electro-discharge machining (EDM) - optical maser Jet Machining (LJM) ray Machining (EBM) Chemical Processes Chemical edge (CHM) chemical science edge (PCM) etc. 1.2. Need for non-traditional mahining processes: Conventional machining sufficed the necessity of the industries over the decades. But new exotic work materials in addition as innovative geometric style of product and parts were putt ton of pressure on capabilities of standard machining processes to manufacture the components with desired tolerances economically. This LED to the event and institution of NTM processes within the trade as economical and economic alternatives to standard ones. With development within the NTM processes, presently there square measure usually the primary alternative and not another to standard processes sure enough technical needs. The following examples are provided where NTM processes are preferred over the intricate shaped blind hole – e.g. square hole of 15 mm 15 mm with a depth of 30 mm 1.3. Definition of AJM In Abrasive Jet Machining (AJM), abrasive particles are created to strike the work material at a high rate. The jet of abrasive particles is carried by carrier gas or air. The high rate stream of abrasive is generated by changing the pressure energy of the carrier gas or air to its K.E. and thus high rate jet. The nozzle directs the abrasive jet during a controlled manner onto the work material, so the space between the nozzle and therefore the work piece and therefore the impingement angle can be set desirably. The high-speed abrasive particles take away the fabric by micro- cutting action in addition as brittle fracture of the work material. Schematically shows material removal process (Fig. 1). AJM is different from standard shot or sand blasting, as in AJM, finer abrasive grits are used and the parameters can be controlled more effectively providing better control over product quality. In AJM, generally, the abrasive particles of around fifty lm grit size
Fig. 1. Schematic diagram of abrasive jet machine.
would collide with the work material at speed of two hundred m/s from a nozzle of I.D. of 0.5 metric linear unit with a standoff distance of around a pair of metric linear unit. The kinetic energy of the abrasive particles would be enough to provide material removal due to brittle fracture of the work piece or even micro cutting by abrasives. 1.3.1. Equipment In AJM, air is compressed in an air compressor and compressed air at a pressure of around 5 bar is used as the carrier gas as shown in Fig.9.1.4 conjointly shows the opposite major components of the AJM system. Gases like greenhouse gas, N2 also can be used as carrier gas which can directly be issued from a gas cylinder. Generally, gas isn’t used as a carrier gas. First older a pressure regulator to get the required operating pressure. The gas is then well-versed true gone through had undergone saw felt responded to suffer an air drier to get rid of any residual water vapor. To remove any oil vapour or particulate contamination constant is older a series of filters. Then the carrier gas enters a closed chamber referred to as the blending chamber. The abrasive particles enter the chamber from a hopper through a gilded sieve. The sieve is consistently vibrated by Associate in nursing magnetism shaker. The mass rate of flow of abrasive (15 gm/min) getting into the chamber depends on the amplitude of vibration of the sieve and its frequency. The abrasive particles are then carried by the carrier gas to the machining chamber via an electromagnetic on-off valve. The machining enclosure is crucial to contain the abrasive and machined particles in an exceedingly safe and eco-friendly manner. The machining is carried out as high velocity (200 m/s) abrasive particles are issued from the nozzle onto a work piece traversing under the jet. 1.4. Abrasive jet machining operations Surface finishing is a broad range of industrial process that alter the surface of a manufactured item to achieve a certain property. Finishing processes may be employed to: improve appearance, adhesion or wettability, solder ability, corrosion resistance, tarnish resistance, chemical resistance, wear resistance, hardness, modify electrical conductivity, remove burrs and other surface flaws, and control the surface friction. In restricted cases a number of these techniques may be wont to restore original dimensions to salvage or repair associate degree item. An unfinished surface is often called mill finish. Polishing associate degreed buffing area unit finishing processes for smoothing a piece piece’s surface victimization
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
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A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx
an abrasive and a piece wheel or a animal skin strop. Technically sharpening refers to processes that use associate degree abrasive that’s affixed to the work wheel, whereas buffing uses a loose abrasive applied to the work wheel. Polishing may be a additional aggressive method whereas buffing is a smaller amount harsh, which leads to a smoother, brighter finish. A common thought is that a cultured surface contains a mirror bright end, but most mirror bright finishes are actually buffed. 1.5. Selection of abrasives Aluminum oxide (Al2O3) silicon carbide (SiC) glass beads, crushed glass and sodium bicarbonate are some of abrasives used in AJM. Selection of abrasives depends on MRR, kind of work material, and machining accuracy. Table offers classification of abrasives and its applications. Tabular column for various Abrasives: (Table 1) Aluminum oxide: Aluminum oxide is employed for its hardness and strength. It is wide used as AN abrasive, as well as a far less costly substitute for industrial diamond. Many types of sandpaper use aluminum oxide crystals. In addition, its low heat retention and low heat build it wide utilized in grinding operations, significantly cut-off tools. As the powdery abrasive mineral aloxite, it’s a serious element, together with oxide, of the cue tip ‘‘chalk” utilized in table game. Aluminum oxide powder is employed in some CD/DVD sprucing and scratch-repair kits. Its sprucing qualities also are behind its use in dentifrice. In restricted cases a number of these techniques is wont to restore original dimensions to salvage or repair Associate in Nursing item. An unfinished surface is often called mill finish. Surface finishing processes is categorized by however they have an effect on the work piece: Removing or reshaping finishing Adding or altering finishing Mechanical processes might also be categorized along due to similarities the ultimate surface end.
diamond resolution is utilized in the sharpening method. Polishing chrome steel may increase the hygienical advantages of chrome steel. The removal of chemical reaction (tarnish) from metal objects square measure accomplished employing a metal polish or tarnish remover; this is often conjointly known as sprucing. To prevent additional unwanted reaction, polished metal surfaces may be coated with wax, oil, or lacquer. This is of specific concern for copper alloy product like brass and bronze. Mechanical properties: The strength of polished product is often more than their rougher counterpart due to the removal of stress concentrations gift within the rough surface. They take the shape of corners and alternative defects that enlarge the native stress on the far side the inherent strength of the fabric. Polishing with terribly fine abrasive differs physically from coarser abrasion, in this material is removed on a molecular level, so the speed is correlative to the boiling purpose rather than to the freezing point of the fabric being polished.
1.7. Selection of abrasives Common Abrasive Materials Synthetic Diamond Cubic Boron Nitride (CBN) Aluminum Oxide Silicon Carbide (Sic)
1.7.1. Aluminum oxide Aluminum oxide is used for its hardness and strength. It is wide used as associate abrasive, as well as a far more cost-effective substitute for industrial diamond (Fig. 2). Many types of sandpaper use aluminum oxide crystals. In addition, its low heat retention and low heat energy create it wide employed in grinding operations, notably cut-off tools. As the powdery Alumina is employed to manufacture tiles, that area unit connected within powdery fuel lines, and flue gas ducting on coal dismissed power stations to shield high wear areas. They are not suitable for areas with high impact forces as these tiles are brittle and susceptible to breakage.
1.6. Polishing Polishing associated buffing square measure finishing processes for smoothing a piece piece’s surface victimization an abrasive and a piece wheel or an animal skin strop. Technically sharpening refers to processes that use associate abrasive that’s affixed to the work wheel, whereas buffing uses a loose abrasive applied to the work wheel. Polishing could be a additional aggressive method whereas buffing is a smaller amount harsh, which leads to a smoother, brighter finish. A common idea is that a cultured surface incorporates a mirror bright end, however most mirror bright finishes are buffed. Polishing is commonly accustomed enhance the looks of associate item, prevent contamination of instruments, remove oxidation, create a reflective surface, or prevent corrosion in pipes. In metallographic and science, polishing is used to create a flat, defect-free surface for examination of a metal’s microstructure under a microscope. Silicon-based sharpening pads or a
Fig. 2. Aluminum oxide.
Table 1 Details of various abrasives. Abrasives
Grain sizes
Application
Aluminum oxide (Al2O3) Silicon carbide (SiC) Glass Beads Dolomite Sodium Bicarbonate
12,20,50 mm 25,50 mm 0.635–1.25 mm 200 mesh 27 mm
Good for cleaning, cutting, deburring Used for similar applications but for hard materials Gives matte finish Etching and polishing Cleaning, deburring and cutting of soft material. Light finishing below 500 °C
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
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A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx
1.7.2. Silicon carbide Silicon Carbide (Sic) is Associate in Nursing inorganic material having mechanical, thermal, electrical and chemical properties, because of that it’s wide employed in developed industries. However, the useful properties of assault ceramic like high hardness, high strength, wear resistance, extreme breakableness and chemical stability create assault machining troublesome and dear through (Fig. 3). Conventional and non-conventional machining methods. Hence, in gift study a summary of previous work on attack ceramic is meted out. Many researchers tried varied strategies for machining of set ceramic from that electro discharge machining method, optical maser machining method, grinding method and diamond turning machining method is that the most applied methods. The theoretical, experimental and simulation studies are thought of for getting important results. The researchers in the main centered on Material removal rate, surface roughness, surface end and power wear rate.
Fig. 5. Nozzle.
2. Experimental setup 2.1. Gas propulsion system:(air compressor) The main purpose of gas system is to supply clean and dry, high speed air or gas for machining. Mostly air, carbon dioxide, Nitrogen etc. are used as gas in gas propulsion system. This system consists, compressor, air filter and drier (Fig. 4). 2.2. Abrasive feeder As the name implies, abrasive feeder is employed to produce abrasive particles in mixture chamber. It is fed through a sieve that
Fig. 6. Plastic pipes for the flow of abrasives.
vibrates at 50–60 cps and mixture magnitude relation is management by the vibration of the sieve and its amplitude. 2.3. Nozzle To direct the abrasive particle on work piece cutting nozzles ar used. They are usually made by tungsten carbide. They are obtainable in each circular and sq. cross section. Its life is sometimes low regarding thirty hours for metal inorganic compound (Fig. 5) 2.4. Machining chamber It is fully closed air tight chamber which control the concentration of abrasive particle around work piece. This is equipped with a vacuum dirt collector that collect used abrasive particle and removed material from mixture chamber. 2.5. Filter It filters the gas before coming into the mechanical device and combining chamber. Hopper: Hopper is employed for feeding the abrasive powder. 2.6. Pressure gauges and flow regulators
Fig. 3. Silicon carbide.
They are accustomed management the pressure and regulate the rate of abrasive jet.
Fig. 4. Gas propulsion system (Air compressor).
Fig. 7. Mitutoyo surftest sj-210.
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343
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A.K. Chaitanya et al. / Materials Today: Proceedings xxx (xxxx) xxx Table 2 Ra values in micrometers. Material
Trail-1 mm
Trail-2 mm
Trail-3 mm
Surface roughness values Micrometers (Ra)
Machined with aluminum oxide Specimen 1 Machined with aluminum oxide Specimen 2 Machined with silicon carbide Specimen 1 Machined with Silicon carbide Specimen 2 Un machined piece
0.011 0.012 0.014 0.015 0.018
0.012 0.013 0.013 0.014 0.017
0.013 0.012 0.012 0.013 0.018
0.012 0.012 0.013 0.014 0.018
2.7. Vibrator
4.4. Surface roughness graph for un machined piece
It is provided below the mixing chamber. It controls the abrasive powder feed rate within the mixture chamber (Fig. 6). 3. Experimental analysis 3.1. Roughness measurement Roughness measurement has been done using a portable MITUTOYO SURFTEST SJ-210, Shown in Fig. The instrument could be a moveable, self-contained instrument for the measurement of surface texture. The parameter evaluations are microprocessor based. The measuring results square measure displayed on associate LCD screen and may be output to associate ex gratia printer or another pc for any analysis. It is equipped with a diamond stylus having a tip radius five lm. The measure stroke continually starts from the intense outward position. At the top of the measuring the pickup returns to the position prepared for following measuring. The selection of cut-off length determines the traverse length (Fig. 7). 4. Results 4.1. Tabular column for Ra values in micrometers Table 2 4.2. Surface roughness graph for aluminum oxide machined piece
5. Conclusion 1) For higher precision work higher pressure and lower standoff distance are adopted to attain a higher accuracy and penetration rate for AJM. 2) The higher standoff distance is preferable where material removal is prime importance. 3) MRR increase with an increase in abrasive jet flow rate, mixing ratio, internal pressure, standoff distance under certain condition. 4) By using aluminum oxide abrasive particles getting better surface finishing compared with silicon carbide abrasive particles.
Further reading
4.3. Surface roughness graph for silicon carbide machined piece
[1] G. Boothroyd, W.A. Knight, Fundamentals of Machining and Machine Tools, Second Edition., Marcel Thomas Decker Iraqi National Congress, New York, 1989. [2] D.D. Charisis, S.O. Koutayas, P. Kamposiora, A. Doukoudakis, Spectrometric analysis of the influence of various backgrounds on the color of glass-infiltrated ceramic veneers, Eur J Esther Dent. 1 (2006) 142–156. [3] B.C. Brosheer, ‘‘How Smooth is Smooth? Part-I, Specification and Evaluation of Machined Finishes”, yank journeyman, McGraw-Hill business firm, 1948, pp. 97–112. [4] CIE 1971: International Commission on Illumination. Colorimeter: official recommendations of the International Commission on Illumination. Publication CIE No.15 (E-1.3.1), Bureau Central First State la CIE, Paris, 1971. [5] M. Gall, W.R. Borg, J.P. Gall, Instructional Analysis, sixth ed., Longman, New York, 1996. [6] Terminology and Parameters, Hummel America, 30, Peter Court, New Britain, CT, 1988. [7] Stavridakis, M.M., Papazoglou, E., Seghi, R.R., Johnston, W.M., Brantley, W.A. Effect of various high-palladium metal-ceramic alloys on the color of opaque and dentin ceramic ware. [8] Jagadeesha T, Assistant professor, Abrasive jet machining, national institute of technology, Calicut. [9] Jigar Kumar P. Patel, Dr. K.V. Modi, Development of abrasive jet machine. [10] Prof. V.K. Jain, Mechanical engineering department I.I.T. Kanpur-208016, Micro machining process. [11] Mistri Ankit N, UG Student, Department of mechanical engineering, Chhotubhai Gopal Bhai institute of technology, Bardoli.
Please cite this article as: A. K. Chaitanya, D. Kishore Babu and K. V. N. Girish Kumar, Experimental study on surface roughness by using abrasive jet machine, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.343