Scaffolds of polycaprolactone (PCL) and PCL composites reinforced with b-tricalcium phosphate (b-TCP) were manufactured aiming potential tissue engineering applications. They were fabricated using a three-dimensional (3D) mini-screw extrusion printing, a novel additive manufacturing process, which consists in an extrusion head coupled to a 3D printer based on the Fab@Home equipment. Thermal properties were obtained by differential scanning calorimetry and thermogravimetric analyses. Scaffolds morphology were observed using scanning electron microscopy and computed microtomography; also, reinforcement presence was observed by X-ray diffraction and the polymer chemical structure by Fourier transform infrared spectroscopy. Mechanical properties under compression were obtained by using a universal testing machine and hydrophilic properties were studied by measuring the contact angle of water drops. Finally, scaffolds with 55% of porosity and a pore size of 450 lm have shown promising mechanical properties; the b-TCP reinforcement improved mechanical and hydrophilic behavior in comparison with PCL scaffolds. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43031.

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The purpose of this work is to present the study of the technical feasibility and functional design of an interchangeable mini head extruder based on a screw with variable section to be used in open-source desktop 3-D printers. The QFD matrix was used during the design planning where the non-commercial users’ requirements were established. Functional structure of the mini head extruder was organized to give support to the mechanical calculation. The choice of a feasible configuration allowed the pre-calculation of the main components of the proposed head which were: screw, barrel and motor system. The materials chosen for the mechanical and rheological calculations were polyamide and the biopolymer PCL, both in powder distribution. Apart from the mechanical design, supported by the QFD, and functional analysis, the mini head extruder was manufactured and assembled, showing its functionality to generate filaments with diameter of 0.7 mm from powder raw material. The complete mechanical and electrical design development and manufacturing of this mini head extruder were made in a period of 24 months. This systematic development demonstrated the importance of the design methodology during the development of the design process and its contribution to the design quality. Besides, the mini head extruder using screw will allow the generation of scaffold structures using biopolymers, as well as to enable comparative studies using different kind of polymers.