Notable Applications of FDM

The recent boom experienced in the 3D printing industry, namely that of FDM technology, provides an opportunity for research laboratories to harness the capabilities of these methods. The low entry cost, combined with cheap and widely available materials makes this an appealing tool for a variety of different uses. The majority of the work discussed in this dissertation has dealt with the application of FDM to the control of ions under atmospheric pressures, yet it is imperative to consider other ways in which additive manufacturing can influence work performed in research laboratories. While not discussed within the context of this work 3D printed components have filled vital roles within the entire scope of my research interests. Any scientific laboratory is stocked with specialized equipment and instrumentation. Such instruments often require home-built fittings, brackets, etc. that may be produced cheaply and on-demand by additive manufacture. However, many scientific applications involve exposure of parts to extreme conditions such as temperature fluctuations, tissue growth media, solvent systems, and even ionizing radiation, conditions not often suitable for traditional thermoplastics.

With the consumer and hobbyist adoption of FDM 3D printing technology a new market has been realized for production and distribution of unique and specialized materials that are available at relatively low cost. Furthermore, there are open-source filament extruders that can be purchased/built which allow for the production of materials that are not available for purchase [2].

Thermoplastic elastomers (TPE) describe a fairly broad range of materials that are most generally referred to as “flexible” materials, due to their elastomeric properties. Because of their inherent flexibility, TPE materials are particularly well-suited for tissue engineering applications where connectivity must be retained while the material undergoes stress and displacement. Several cases have been demonstrated in which a printed TPE scaffold was used as a support structure for tissue growth [3-5].

The production of application-derived materials suitable as feedstock for FDM is not always straightforward, often requiring extensive testing and modification for optimal performance. Because of this, it is often more feasible to simply modify the surface of a traditional thermoplastic for compatibility with its planned usage. Surface modification to achieve biocompatibility of 3D printed ABS (one of the most common and versatile FDM feedstocks) was recently demonstrated by McCollough et al. Through surface treatment of printed ABS they were able to reduce non-specific protein binding as well as increase biocompatibility [6]. These modifications serve to improve the performance of 3D printed microfluidic devices, a field which has shown rapid growth in recent years [7]. These 2 examples highlight just some of the possibilities that FDM can provide in the development of new medical devices and diagnostic platforms.

Another challenge faced in the manufacture of parts by FDM is the geometric constraints regarding free-hanging artifacts, otherwise known as overhangs. These features lack the base on which a layer of plastic can be deposited and therefore support structures can be employed. Support structures can be printed to simply break away from the part once completed, but this can leave undesirable surface artifacts. Alternatively, through the use of dissolvable support material, such as PVA the support structures can be easily removed by soaking the object in a solvent [8].

 
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