Non Traditional machining lecture slides
- 1. T. ANJANEYULU ASSISTANT PROFESSOR DEPARTMENT OF MECHANICAL ENGINEERING UNCONVENTIONAL MACHINING PROCESSES YEAR: IV – I MECH
- 3. MACHINING-removal of material from a raw material in order to obtain the desired shape and dimensions for final part. based on principle and technology used classified into two types, Conventional Machining Processes Un Conventional Machining Processes(UCMP)
- 4. CMP UCMP Mechanism of material removal: shear deformation along the shear plane and chip formation in work piece by use of cutting tool and machine tool The cutting tool and work piece are always in physical contact, with a relative motion against each other Mechanism of material removal: Impact erosion on work piece or Melting and evaporation or Corrosive reaction source of energy : mechanical, thermal, chemical and electrochemical. Types- Turning, Shaping, Drilling, milling.. Types- AJM, USM,ECM, ECG,EBM… PRODUCTS-
- 5. WHY UCMP COMPLEX GEOMETRY A zigzag cavity in a block of high strength alloy is to be finish machined --traditional machining is not feasible..
- 6. Machining of small cavities , slits, blind holes or through holes— traditional machining is not feasible
- 7. Work piece material is too hard, strong, or tough blades and vanes for aerospace and stationary gas and steam turbine, Made of Nickel-base super alloys
- 8. • Deep hole with small hole diameter – e.g. φ 1.5 mm hole with l/d = 20 • Machining of composites
- 9. These requirements led to creation of new techniques which are adopted in Non Traditional Manufacturing(NTM)
- 10. 4.1 SYLLABUS-JNTUH UNIT-I SYLLABUS Introduction: Need for non- traditional machining methods-classification of modern machining process-considerations in process selection, Materials & applications Ultrasonic machining- Elements of the Process, Mechanics of material removal process parameters, Economic considerations, Applications And Limitations TEXT BOOK : 1. Advanced machining processes/ VK Jain/ Allied publishers. REFERENCES : 1. Modern Machining Process / Pandey P.C. and Shah H.S./ TMH. 2. New Technology / Bhattacharya A/ The Institution of Engineers, India 1984. 2. Modern Production / Operations Management / Baffa & Rakesh Sarin. 4. Unconventional Machining Processes - Jagadeesha .T
- 11. Comparison Factor Conventional Manufacturing Processes Non-Conventional Manufacturing Processes Mechanism of material removal 1.Generally macroscopic chip formation by shear deformation. Material removal may occur with chip formation or even no chip formation may take place. 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 Physical contact of tool & Workpiece There may be a physical tool present. for example a cutting tool in a Lathe Machine There may not be a physical tool present. For example in laser jet machining, machining is carried out by laser beam. However in Electrochemical Machining there is a physical tool that is very much required for machining. Tool hardness Cutting tool is harder than work piece At room temperature as well as under machining conditions There may not be a physical tool present. For example in laser jet machining, machining is carried out by laser beam. However in Electrochemical Machining there is a physical tool that is very much required for machining. Energy form Material removal takes place due to application of cutting forces – energy domain can be classified as mechanical Mostly NTM processes do not necessarily use mechanical energy to provide material removal. They use different energy domains to provide machining. For example, in USM, AJM, WJM mechanical energy is used to machine material, whereas in ECM electrochemical dissolution constitutes material removal.
- 12. Comparison Factor Conventional Manufacturing Processes Non-Conventional Manufacturing Processes Tool life Tool life is lessdue to high surface contact and wear. Tool life is more waste of material Higher waste of material due to high wear. Lower waste of material due to low or no wear. MRR High low accuracy and surface finish. Lower accuracy and surface finish. Higher accuracy and surface finish. Geometry Complex 3D objects and cavities cannot be produced More complex geometry and 3D objects can be produced Mechanics
- 13. Comparison Factor Conventional Manufacturing Processes Non-Conventional Manufacturing Processes capital cost Lower capital cost Higher capital cost set-up of equipment Easy set-up of equipment. Complex set-upequipment. Skilled operator Skilled or un-skilled operator may required Skilled operator required. Operating Generally they are manual to operate. Generally they are fully automated process. prototype parts They cannot be used to produce prototype parts very efficiently and economically. Can be used to produce prototype parts very efficientlyAnd economically.
- 14. NTM Classification Based on the principle form of energy nontraditional manufacturing processes can be classified into following groups: 1. Mechanical - Erosion of work material by a high velocity stream of abrasives and/or fluid Example: USM, AWJM, WJM. 2. Electrical - Electrochemical energy removes material Example: ECM, ECD, ECG. 3. Thermal - Thermal energy applied to small portion of work surface, removes material by fusion and/or vaporization Example: EDM, WEDM, EBM, LBM, PAM, IBM 4. Chemical - chemical etchants selectively (using a mask) remove a portion of a workpiece. Example: Chemical milling, Blanking, Engraving and Photochemical machining.
- 15. Principal of NTM Processes Mechanical Energy Thermal Energy Methods Chemical Methods
- 18. COMPARATIVE ANALYSIS & SELECTION OF UCM process Physical parameters
- 19. MRR
- 21. For micro-drilling operation, the only process which has good capability to micro drill is laser beam machining while for drilling shapes having slenderness ratio, l/D < 20, the process USM, ECM and EDM will be most suitable. EDM and ECM processes have good capability to make pocketing operation (shallow or deep). For surface contouring operation, ECM process is most suitable but other processes except EDM have no application for contouring operation.
- 24. The process capabilities of non-conventional manufacturing processes have been compared in the metal removal rates by ECM and PAM are respectively one-fourth and 1.25 times that of conventional whereas others are only small fractions of it. Power requirement of ECM and PAM is also very high when compared with other non-conventional machining processes. This involves higher capital cost for those processes. ECM has very low tool wear rate but it has certain fairly serious problems regarding the contamination of the electrolyte used and the corrosion of machine parts. The surface finish and tolerance obtained by various processes except PAM is satisfactory.
- 25. Economics of the processes
- 26. The capital cost of ECM is very high when compared with traditional mechanical contour grinding and other non- conventional machining processes whereas capital costs for AJM and PAM are comparatively low. EDM has got higher tooling cost than other machining processes. Power consumption is very low for PAM and LBM processes whereas it is greater in case of ECM. The metal removal efficiency is very high for EBM and LBM than for other processes. In conclusion, the suitability of application of any of the processes is dependent upon various factors and must be considered all or some of them before applying no conventional processes.