Dual Material Rapid Prototyping Techniques for the Development of Biomedical Devices. Part 2: Secondary Powder Deposition

Polymeric drug delivery devices play an important role in drug administration. However, the current polymeric drug delivery device fabrication methods lack precision. This impairs the quality of the devices, resulting in a decrease in the efficiency and effectiveness of drug delivery. The concept of building parts layer by layer out of powdered raw materials makes selective laser sintering (SLS) a suitable process for fabricating polymeric matrix drug delivery devices. The current SLS process is not capable of processing two or more materials separately. This work explores the possibilities of using SLS to perform a dual material operation by developing two process models. The two processes can then be integrated to form a dual or multimaterial fabrication technique and act as a foundation for future work in multimaterial applications such as polymeric drug delivery device fabrication. Accordingly, two papers are presented.

In this paper, Part 2, the emphasis is on a secondary powder deposition method, which is an electrostatic technique based on electrography. Developed toner on the photoconductor is scraped off using mechanical shearing and is deposited using an electrostatic force by electroplating. Results have shown that by reducing the distance between the photoconductor and surface of deposition, the resolution of the printout can be refined. Other important factors include the efficiency of powder removal from the photoconductor, printing speed, and the traversing speed during deposition.