Subtractive Prototyping Processes

The process time depends on the complexity of the 3D microstructures therefore, it is commonly used for prototyping. An extensive review on stereolithography can be found in Reference 119. The latter method is a subtractive manufacturing process that uses a focused high-intensity laser beam to evaporate the material from the surface. Laser ablation is mostly used to fabricate microchannels in thermosetting polymers such as polyimide due to its physical properties. Microstructures of nanometer scale have been danonstrated, but the surface roughness and properties using laser... 

There are three main ways to create a rapid prototype. Formative techniques use machines to make raw materials into the desired shape. Subtractive processes start with a large solid, then remove material to make the shape desired. Additive processes rely on layering material over and over until the part or product reaches its final position and shape. 

Rapid prototyping is an "additive process, combining layers of plastic to create a solid object. In contrast, most machining processes (milling, drilling, grinding) are "subtractive processes that remove material from a solid block. 

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