The demand for miniaturized micro-devices (1–1000μm) with high aspect ratio and superior surfaces has been rapidly increasing in aerospace, automotive, biomedical, optical, military and micro-electronics packaging industries. However, fabrication of micro and miniature components is still a challenging task. Age old machining techniques and conventional machine tools cannot be utilized for machining tiny components with feature size in micron level and surface roughness in sub-micron level.
Conventional machining processes, which employ mainly mechanical energy for bulk removal of material from workpiece, are not suitable for getting miniaturized components. Various non-traditional machining (NTM) processes, precision manufacturing technologies and micro-electromechanical systems (MEMS) are widely used to satisfy the perpetual demand of micro products. Beside these processes, mechanical based micro-manufacturing technology is emerging as another choice for an effective method to fabricate micro complicated 3-D features on a wide variety of materials including metals, polymers, composites and ceramics. Some of the micro-machining processes are enlisted below.
Non-Traditional Machining (NTM) processes
Non-Tradition Machining (NTM) processes are newly developed material removal processes that utilize various forms of energy in their direct form to remove excess material from workpiece in order to get desired shape, surface finish and tolerance. Such processes are also called Unconventional Machining Processes or Advanced Machining Processes (AMPs). They can be used for generating complicated features as well as to obtain quality finished surface. In rare cases, they can also be for bulk removal purpose. Few NTM processes are enlisted below.
- Abrasive Jet Machining (AJM)
- Abrasive Water Jet Machining (AWJM)
- Ultrasonic Machining (USM)
- Chemical Machining (CHM)
- Electro-Chemical Machining (ECM)
- Electro Discharge Machining (EDM)
- Laser Beam Machining (LBM)
- Electron Beam Machining (EBM)
- Plasma Arc Machining (PAM)
- Ion Beam Machining (IBM)
Micro-electromechanical Systems based processes
Micro-electromechanical Systems (MEMS) based processes are mainly used in semiconductor industries such as for fabrication of integrated circuit (IC), chips, etc. These processes require a tight work-room environment to precisely produce extremely small products. Most of these processes employ controlled chemical reaction for removal of material from workpiece. Till now the application of MEMS processes are confined mainly within electronic industries because of a large number of constraints and slow process. Few MEMS processes are enlisted below.
- Wet etching
- Dry etching
- Surface micro-machining
- LIGA (German acronym from Lithographie, Galvanoformung, Abformung translated to English as lithography, electroforming and molding)
Conventional precision manufacturing processes
Conventional machining processes are well established and such processes can be manipulated to produce mirror finish surface of roughness below 20nm. One basic advantage is that these processes can easily accommodate substantially large components. Basically, conventional precision machining processes focus on producing highly finished surface irrespective of size of the component. Examples of such processes are enlisted below.
- Precision turning
- Precision grinding
Mechanical micro-machining processes
Whereas precision machining processes emphasis on surface generation, micro-machining processes mainly focus on micro-feature generation. Features of size down to 20µm can easily be fabricated by these processes. They can also produce quality surface; however, finishing capability is usually below that for precision machining processes. Examples of such process include:
Abrasive jet machining (AJM)
AJM is considered as a mechanical energy based non-traditional machining process that utilizes a jet of gas-abrasive mixture for removing material. Get an overview of AJM process, mechanism, parameters, equipment, MRR, accuracy, capability, pros and cons, applications, controlling, etc. Browse all articles…