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  • 1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 28 NEW APPROACH TO CASTING DEFECTS CLASSIFICATION AND OPTIMIZATION BY MAGMA SOFT M. Chandra Sekhar Reddy1* , Talluri Ravi Teja2 1 Associate Professor, Department of Mechanical Engineering, UCE(A), Osmania University. 2 Research Scholar, UCE(A), Osmania University. ABSTRACT Foundry industry suffers from poor quality and productivity due to the large number of process parameters, combined with lower penetration of manufacturing automation and shortage of skilled workers compared to other industries. Global buyers demand defect-free castings and strict delivery schedule, which foundries are finding it very difficult to meet. Casting defects result in increased unit cost and lower morale of shop floor personnel. The defects need to be diagnosed correctly for appropriate remedial measures, otherwise new defects may be introduced. Unfortunately, this is not an easy task, since casting process involves complex interactions among various parameters and operations related to metal composition, methods design, molding, melting, pouring, shake-out, fettling and machining. For example, if shrinkage porosity is identified as gas porosity, and the pouring temperature is lowered to reduce the same, it may lead to another defect, namely cold shut. In this work, we present a 3-step approach to casting defect identification, analysis and rectification. The defects are classified in terms of their appearance, size, location, consistency, discovery stage and inspection method. This helps in correct identification of the defects. Keywords: Casting Defects, Classification, Gating System Design, MAGMA SOFT, Optimisation. 1. INTRODUCTION Metal casting is one of the direct methods of manufacturing the desired geometry of component. It is one of the primary processes for several years and one of important process even today in the 21st century. Early applications of casting are in making jewellery items and golden idols. Today, casting applications include automotive components, spacecraft components and many industrial & domestic components, apart from the art and jewellery items. INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) ISSN 0976 – 6340 (Print) ISSN 0976 – 6359 (Online) Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME: www.iaeme.com/ijmet.asp Journal Impact Factor (2014): 7.5377 (Calculated by GISI) www.jifactor.com IJMET © I A E M E
  • 2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 29 The principle of manufacturing a casting involves creating a cavity inside a sand mould and then pouring the molten metal directly into the mould. Casting is a very versatile process and capable of being used in mass production. The size of components is varied from very large to small, with intricate designs. Out of the several steps involved in the casting process, moulding and melting processes are the most important stages. Improper control at these stages results in defective castings, which reduces the productivity of a foundry industry. Generally, foundry industry suffers from poor quality and productivity due to the large number of process parameters, combined with lower penetration of manufacturing automation and shortage of skilled workers compared to other industries. Also, Global buyers demand defect-free castings and strict delivery schedule, which foundries are finding it very difficult to meet. LITERATURE REVIEW Basic Principles of Metal casting and Metal casting processes like Sand casting, Die casting Investment casting and Expendabele Mold Casting and Non Expendabele Mold Casting. Parts of Gating System Sprues, Runners, Gates, Risers, vents Cores and Drafts. These Studies is done in Principles of Metal Casting by Richard Heine, Carl Loper, Philip Rosenthal That is automatic supervision and control of the technological process of manufacturing the elements from aluminium alloys and of the methodology of the automatic quality assessment of these elements basing on analysis of images obtained with the X-ray defect detection, employing the artificial intelligence tools. L.A. Dobrzański and M. Krupiński presented a new methodology in the paper. The optimal processing parameters for the cooling were obtained from the analysis of fluid flow and solidification. Numerical simulations of mold filling and solidification were used to optimize the casting process. The simulations were used to predict the temperature distributions and solidification sequences in the casting to optimize the casting conditions. S. M. Yoo, et. al, used to simulate the fluid flow in a sand mold. This paper deals with Casting defects in offset printing press cylinder and their remedies studied by Roby Joy et. al. A printing press is a mechanical device for applying pressure to an inked surface resting upon a medium (such as paper or cloth), thereby transferring an image. D.N.Shivappa1 et. al, presented analysis of casting defects and identification of remedial measures carried out at Dakshin Foundry Ltd, Bangalore, India. Diagnostic study carried out on Trunion Support Bracket (TSB) Castings revealed that the contribution of the four prominent defects in casting rejections are sand drop, blow hole, mismatch, and oversize. It was noticed that these defects are frequently occurring at particular locations. Casting Simulation and Optimisation has become a powerful tool to visualize mould filling, solidification and cooling, and to predict the location of internal defects such as shrinkage porosity, sand inclusions, and cold shuts. This Paper Describes the benefits of Casting simulation. B. Ravi, 2008, “Casting Simulation and Optimization”, Indian Foundry Journal. 2. PROBLEM STATEMENT Early in Foundry Industry the defects classified after the manufacturing. By taking that casting and doing defect testing like Radiography or Ultrasonic Testing Method. In this process the rejections are 60%.By adding MAGMA SOFT in this process the estimated rejections are 15%. Every 10 castings 4-6 castings are rejected. Every time affecting defects are Blow holes, Shrikage, Misrun and Cold shut. More process variation due to more human involvement which leads to heavy rejection.
  • 3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 30 Less Automation Average cost of one casting is Rs.6000/- due to this rejection and again scrap recycle the cost is almost all 6000/- to 6100/-. Cost saving through MAGMA Customers In-Time Dispatch of Castings 3. PRESENT APPROACHES FOR ANALYSIS OF CASTING DEFECTS At present, casting defect analysis is carried out using techniques like historical data analysis, cause-effect diagrams, design of experiments. They are briefly explained in this section. 3.1 Historical Data Analysis To understand this concept, data for occurrence of defects are collected from one of leading casting manufacturer in Maharashtra for one year. From this data, occurrence chart has been prepared which further helps to identify occurrence major defects in castings. These data further help to prepare the chart for occurrence of defect. Table 1: Historical Data of casting defects Defects Rejected Quantity Job Rejection % Defects Rejected Quantity Job Rejection % Cold Shut 205 2.03 Cores Broken 16 0.17 Crush 188 2.11 Mismatch 13 0.14 Knock Crack 165 1.85 Sub. Contract Fettling Fault 10 0.11 Blow Hole 123 1.38 Run Out 7 0.07 Contractor’s Houling Cracks 55 0.62 Hard 7 0.07 Bad Mold 42 0.47 Slurry Penetration 4 0.04 Scab 40 0.45 Low Hardness 3 0.03 Fet Crack 32 0.36 Core Scab 1 0.01 Shrinkage 31 0.34 Swell 1 0.01 Slag 23 0.25 Sink 1 0.01 Bad Core 19 0.21 Others 3 0.003 TOTAL 989 11.1012 4. METHODOLOGY 4.1 Present Inspection Methods for Defects 1. Process Inspection 2. Visual Inspection 3. Dimensional Inspection
  • 4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 31 Flow Diagram of Foundry industry Proposed Flow Diagram using Magma Start Core MakingPattern Making Moulding 2D and 3D Modeling MeltingFetllingInspection Correction in Method and Tooling Sample Submission MAGMA Simulation `Pattern Making Start Core Making Moulding 2D and 3D Modeling MeltingFetllingInspection Correction in Method and Tooling Sample Submission
  • 5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. • Only 1 Trail below 5% rejection • No need of trial and error method • Document evidence on method to the customer • Reduction in delivery time • Consistence in the casting quality • More business on customer satisfaction for early submission to get more orders 4.2 Proposed Gating System Design PART DESCRIPTION/ DRG. NO: AXLE HOUSING/ YZ 1 RUNNER BAR DIMENSSIONS: 24 X 30 X 45 RUNNAER BAR CROSS SECTIONAL AREA: 1215 mm² INGATE AREA: INGATE AREA = 12.08CM² = 1208 MM² (Considered 1073MM²) TAKE 3 INGATES THEREFORE AREA OF EACH INGATE = 358MM² INGATE DIMENSSIONS: 30X 35 X 11 MM rnational Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 32 Only 1 Trail below 5% rejection No need of trial and error method evidence on method to the customer Consistence in the casting quality More business on customer satisfaction for early submission to get more orders Proposed Gating System Design PART DESCRIPTION/ DRG. NO: AXLE HOUSING/ YZ 120704 RUNNER BAR DIMENSSIONS: 24 X 30 X 45 24 45 30 RUNNAER BAR CROSS SECTIONAL AREA: 1215 mm² H=320mm C=403mm P=201.5mm M=5.93mm = 1208 MM² (Considered 1073MM²) THEREFORE AREA OF EACH INGATE = 358MM² 30X 35 X 11 MM rnational Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), More business on customer satisfaction for early submission to get more orders
  • 6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 33 SMALL END BIG END MIDDLE END FLOW OFF DETAILS ON BIG END: Ø 16 X Ø20 X 85 MM LENGTH 1 NO ON SMALL END: Ø 16 X Ø20 X 100 MM LENGTH 1 NO 5. GATING SYSTEM Figure 1: Gating System Proposal 1 GATING RATIO: 1385: 1208: 1073 1:0. 87: 0.77 FILTER DETAILS: 100X 100X 22 MM FEEDER DETAILS: ON SMALL END: 10/17K SLEEVE RISER ON BIG END: 9/17K SLEEVE RISER MIDDLE: 10/17K SLEEVE RISER.
  • 7. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 34 Figure 2: Gating System Proposal 2 5.1 Gating Geometry Cad model insert in to the MAGMA soft Start the simulation select the area which it should be velocity, temperature, speed, solidification and porosity. It will shows which parts the defects are going to occur(shown in fig.4) so some changes in gating design. Figure 3: Gating Geometry in MAGMA SOFT
  • 8. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 6, June (2014), pp. 28-35 © IAEME 35 5.2 Solidification and Liquid After analysis of Solidification and liquid of porosity Figure 4: Porosity spots 6. CONCLUSION From this study a method is proposed for Defect Prevention like blow hole, shrinkage etc. Reduction in lead time and sample products is achieved. A suggestion is made for Validation through MAGMA before manufacture. Cost saving can be done by using through MAGMA, and Customer In-Time Dispatch Without MAGMA it will take 3 months to manufacture, whereas with MAGMA it will take 1 month to manufacture. A Study conducted in Foundry department of Hinduja Foundry Producing Castings. The Prominent defects occurred in castings were identified by Radiography Testing. After considering the various aspects, two suggestions were put forward for reducing the defect density. From the two suggestions, gating system and Magma software implemented. By implementing the suggestions, 15% reduction in rejection rate was estimated. REFERENCES 1. Anderson, J.V. & Karsay, S.I., 1985., “Pouring rate, pouring time and choke design for S.G. Iron Castings”. British Foundryman. 2. Gerhardt Jr., P.C. “Computer applications in Gating & Risering System Design for Ductile Iron Castings” AFS Transactions. 3. Journal by Dr D.N. Shivappa, Mr Rohit, Mr. Abhijit Bhattacharya, “Analysis of Casting Defects and Identification of Remedial Measures”., Dakshin Foundry ltd. 4. Peter Beeley, “Foundry Technology”, Butter Worth Heinemann, 2nd ed., 2001. 5. B. Ravi, 2008, “Casting Simulation and Optimization”, Indian Foundry Journal, Special Issue. 6. Richard Heine, Carl Loper, Philip Rosenthal, 1984, “Principles of Metal Casting”, Tata McGraw Hill Publications, New-Delhi. 7. Cherian Paul and Parvathy Venugopal, “Modelling of Interfacial Heat Transfer Coefficient and Experimental Verification for Gravity Die Casting of Aluminium Alloys”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 1, Issue 1, 2010, pp. 253 - 274, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359. 8. M.Narasimha, R.Rejikumar and K. Sridhar, “Statistical Methods to Optimize Process Parameters to Minimize Casting Defects”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 3, 2013, pp. 11 - 23, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359.