The number and diversity of technologies to produce microcomponents and microproducts is enormous. Those could be classified first as top-down manufacturing methods; starting from bigger building blocks and reducing them into smaller pieces. Second as bottom-up manufacturing methods, in which small particles such as atoms/molecules are added for the construction of bigger functional structures. And third as either the development of entirely new technologies or combination of existing technologies.

Similarly, many other classifications for micromanufaturing technologies have been reported. Mazusawa [39] for instance, classified micromachining technologies according to their working principle or phenomena giving the advantages and disadvantages of each of them. Table 2.3 depicts these considerations combined with a description of the process/material interaction.

Madou listed most popular miniaturization techniques with their respective characteristics organising as traditional or non-traditional methods and lithographic or non-lithographic method and gave an extensive overview of the existing microfabrication technologies [2] (see Table 2.4).

Some other authors divided the micromanufacturing technologies in removal, deposition and molding [37], others from University Nebraska-Lincoln made a classification considering technologies which used tools (solid or image) or masks (anisotropic and isotropic) [38], etc.

However, Brinksmeier’s classification [38] (see Fig. 2.17) is currently one of the most widespread and it is the accepted one in this thesis. The machining of precision parts and micro structures is subdivided into two general types of technologies having different origins; MicroSystem Technologies (MST) and MicroEngineering Technologies (MET). MST are qualified for the manufacture of products of Micro Electro Mechanical Systems (MEMS) and Micro Opto Electro Mechanical Systems (MOEMS). MET comprise the production of highly precise mechanical components, moulds and microstructured surfaces.

Next, regardless of its origin, Brinksmeier classifies the micromanufacturing technologies in four groups:

·         MEMS processes, like UV-lithography, silicon-micromachining and LIGA.

·         Energy assisted processes like Laser Beam Machining, Focused Ion Beam Machining, Electron Beam Machining and Micro Electro Discharge Machining.

·         Mechanical processes like diamond machining (e.g. turning, milling, drilling and polishing), micromilling or microgrinding.

·         Replication techniques like forming, injection moulding or casting. These technologies are suggested in a class on their own, although they require a previous micromanufacturing step to achieve the moulds.

·         In addition to these four groups, Brinksmeier includes an additional group where important steps for micromanufacturing such as handling, assembly and metrology appear.

Fig. 2.17 shows graphically the Brinksmeier´s classification although it should be mentioned that groups are not fully independent among themselves and that, there can be an overlapping between the categories. The size of the arrows indicates how frequently each group of processes are employed in the MST and MET technologies.

In the following sections most widespread processes and production systems used in micromanufacturing will be exposed briefly.

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