Non-traditional machining processes generally replace traditional machining. They are used when traditional machining or grinding cannot be used, often because the materials are too hard.
Limitations of traditional processes:
Chip formation is an expensive and difficult process
Large amount of energy and money is required
Chips are waste material and unwant products
Further expenditure of energy and money to remove chips, dispose or recycle
Large amount of energy ends up as undesirable heat resulting in problems of distortion and surface cracking
Cutting forces cause problems in work-holding, causing distortion
Undesirable deformation and residual stresses require further processing
definite limitation with regard to delicacy of the work that can be machined.
Non-traditional machining processes can be divided into 4 main groups:
Chemical - Chemical reaction, sometimes enhanced by electrical or thermal energy to affect material removal
Electro-chemical - Material removed by electrolytic dissolution
Mechanical - erosion process enhanced by mechanical energy
Thermal - high temperature in localized regions melt and vaporize materials (e.g. Electro-Discharge Machining (EDM))