Nontraditional Manufacturing Processes: MF30604

A K NathLecture No.-1Introduction to NTMPs

Fabrication of large size domes

Fabrication of Micro-lens

60µm square hole Curved slot in SS

in Si

Conventional Machining Processes (Material Removal):Primarily rely on electrical motors and hard tool materials to perform tasks e.g. Turning, Drilling, Boring, Milling, Shaping, Sawing, Slotting, & Grinding etc.

Main Characteristics of Conventional Machining:* Material removal by chip formation * Material removal by mechanical force * Cutting tool – harder than work piece under machining condition* Direct mechanical contact - residual mechanical & thermal stress.

Demand for Products with New exotic work materials: Improved mechanical, thermal, & chemical

propertiesSuper alloys, ceramics and composites

* Too hard / brittle to machine with traditional process* Materials too flexible / slender to cut or clampEx: Machining Polycrystalline diamond

- fast wear of grinding wheel;Silicon wafer, Ceramic – Damage during machining

60µm square hole in Si Curved slot in SS

Micro-lenses

Quartz

Need of Modern Manufacturing Processes !Challenges & Competition in Manufacturing Industries:New Products - Better Performance, More Features, More Durable, Less Production Time, Energy Efficient, Low cost,

Innovative designs, complex shapes, high precision & high surface quality * Stringent design requirements * Micro- Nano Sizes

Other requirements of the New Manufacturing Process

Low machining cost* Automated processing, Fast production

Photochemical Machining Electro-Discharge Machining

Rapid change of Product design * Elimination of Traditional tooling to reduce time & cost

Less Temperature rise or residual stresses

Modern / Nontraditional Manufacturing processes employingNew tools andNew forms of energy

Developed asEfficient and economic alternatives to conventional ones

Often the first choice for certain technical requirements.

Modern / Nontraditional Manufacturing Processes differ to Traditional Mfg. Processes in following aspects ⇒

Unconventional Energy Sources : Thermal, Chemical, Kinetic Energy ----

Processing usually not by direct MECHANICAL contact: Nontraditional mechanism of interaction between the tool and work

piece: Evaporation, Ablation, Melt Ejection, Dissolution, Erosion----

Nontraditional media to transfer energy from the tool to the work piece : Photons, E-beam, Dielectric media, Electrolytic media, Water, Abrasive slurry.

Basic NTM Process Groups:

* Thermal NTM Processes- Laser Beam Machining (LBM)- Electron Beam Machining (EBM) - Plasma Arc Machining (PAC)- Electrical Discharge Machining (EDM)

* Mechanical NTM Processes( Plastic deformation / Abrasive Erosion)- Abrasive Jet Machining (AJM)- Ultrasonic Machining (USM)- Water Jet Machining (WJM)- Abrasive Water Jet Machining (AWJM)

* Electrochemical NTM Processes- Electrochemical Machining (ECM)- Electrochemical Grinding (ECG)

* Chemical NTM Processes- Chemical Machining (CHM)- Thermo chemical Machining (TCM)

* Kinetic Energy ( Atom by atom knocking) - Ion beam

Characteristics of Modern / Non Traditional Machining (NTM) Processes:

Mostly NTM processes do not use mechanical energy for material removal.They use different forms of energy for machining.

Example, USM, AJM, WJM - Mechanical energyECM- Electrochemical dissolutionLaser, EDM, EB - Thermal

Material removal with chip formation or even without chip formationExample: AJM - Microscopic size chips

ECM - Electrochemical dissolution at atomic level

In NTM, Physical tool may or may not be present.Example: Laser beam machining- No tool,

Electrochemical Machining- Physical tool needed

In NTM, Tool need not be harder than the work piece material.Example: EDM, copper tool to machine hardened steels.

Nontraditional media for energy transfer:EDM: Dielectric fluid,Laser: Coherent photon beam

Attributes of Nontraditional Machining Processes:

Increased Productivity: Faster operation Reduction in the number of overall operations;

Reduced Rejection: Improved repeatability Reduction in in-process breakage of fragile work piece.

Perform operation not feasible by traditional Manufacturing Processes,Example drilling holes of very high depth to width aspect ratio, 100:1

Easy automation, On-line Process Monitoring & Control: Increased reliability, repeatability; reduced human involvement

Versatile & Virtually unlimited Capability: Ex.- Laser can cut most materials of any hardness: diamond, metals, concrete, glass, plastics, textiles, wood etc.

Drill holes of any diameter

Course Outline by Topical Areas:

Introduction to Nontraditional Manufacturing Processes

Thermal Processing:

Laser Beam Machining (LBM): Fundamentals of Materials Processing- (Lasercutting, drilling, welding, surface modification- hardening, alloying, cladding;marking, micro-machining, laser rapid prototyping & manufacturing) Equipment forLaser Beam Processing

Electron Beam Machining (EBM) Fundamentals of Materials Processing (E-beam machining, welding, lithography)

Plasma Arc Machining (PAM): Cutting, Welding & Plasma Spraying

Ion-Beam Machining (IBM): Ion Beam removal, deposition, surface treatment

Mechanical NTM Processes( Plastic deformation / Abrasive Erosion)- Abrasive Jet Machining (AJM)- Ultrasonic Machining (USM)- Water Jet Machining (WJM)- Abrasive Water Jet Machining (AWJM)

Objective of this course:

Learn about the basic theory, working principle, and characteristics ofdifferent nontraditional manufacturing processes.

Identify critical process variables and their effect on process performance and product quality

Develop mathematical model relating MRR with machining parameters

Develop understanding to properly assess the capabilities, limitations, andpotentials of nontraditional manufacturing processes

Examples where NTM processes is the first choice

Intricate shaped blind holes- e.g. square holes of say 10x10mm with a depth of20mm ⇒ EDM / ECM

Machining hard materials- e.g. Diamond, Inconel, Ti-Alloys, Composites,Ceramics or Carbides ⇒ EDM, ECM, LBM

Small diameter holes with large aspect ratio (0.5mm φ, 10mm l)⇒LBM, EBM, EDM

Flexible , Brittle materials ⇒ WJ, AWJ, EDM, PCM, LBM, EBM

Laser Cutting

Abrasive Machining

Course Materials : Lecture Notes

Reference Books :

1. Nontraditional Manufacturing Processes Gary F. Benedict, Marcel Dekker,Inc

2. Modern Machining Processes P C Pandey & H S Shan, Tata McGraw-Hill

3. Nonconventional Machining P K Mishra, Narosa Publishing House

4. Manufacturing Science Amitabha Ghosh & A K Mallik, Affiliated East-West Press

5. www.nptel.iitm.ac.inNational Programme on Technology Enhanced Learning (NPTEL)Course- IIT Kharagpur- Manufacturing-Module 9 (on NTM)Lessons 35-40.

6. Laser Material Processing, by W M Steen