Método de desenvolvimento de órtese personalizada de baixo custo para a manufatura aditiva

Abstract

The use of the Additive Manufacturing (AM) has improved the production of customized assistive products, but its use needs to generate the digital geometric model first. One of the alternatives to get it is with the use of 3D scanners. After the scanning, hardly the result achieved, usually a digital STL (stereolithography format) mesh of the 3D surface of the physical model, can be used directly in AM. Therefore, it is required some mesh treatments in 3D CAD (Computer-Aided Design) programs. Some of these tools, both 3D scanners and 3D CAD programs, are feasible but high cost. In addition, the mesh treatment step is not addressed in the studies found, hampering the spread of these technologies. In this way, the present work proposes a low cost method for the development of upper limb orthosis aimed at manufacturing by AM, focusing mainly on the steps of mesh treatment and orthosis modeling. As object of study were used 12 gypsum molds of wrist, hand and fingers made by an occupational therapist. The 3D digitizing of plaster casts occurred using two low-cost systems, the Kinect 360 sensor and the Remake program, and a high-cost scanner to serve as a reference, the REVscan. For the steps of mesh treatment and orthoses modeling, two free 3D CAD programs were used: Blender and Meshmixer. The lowcost scanners generated meshes that were validated by comparing them to those generated by REVscan. Unlike Remake, Kinect generated non-defective meshes and in less time, however, presented the largest dimensional deviations and the largest file sizes. The defects presented in the meshes generated by Remake were of the gaps type and were corrected successfully by 3D CAD programs. In the mesh treatment step, it was verified the relevance of the procedure of smoothing the edges in the final orthosis result. The results highlighted the importance of the meshes treating step for the development of assistive products aiming the manufacture by AM. In general, it was possible to develop customized orthoses using low-cost tools. The procedures described in this study can assist in the development of assistive products and facilitate the dissemination of this knowledge in companies and institutions that provide orthosis.