Avaliação de sistemas de digitalização 3D de baixo custo aplicados ao desenvolvimento de órteses por manufatura aditiva

Abstract

People with cerebral palsy could have wide range of postural changes, the most characteristic are resulting from spasticity. Custom orthosis use can be prescribed in this context aiming increase functional performance and other therapeutic goals. The additive manufacturing is an alternative to the custom assistive products fabrication, such as orthoses. In this context 3D scanning is an important step, considering that the user anatomy is a geometric reference to product development in 3D CAD for further fabrication. However, the 3D scanners have high costs, one of the factors that hinder the popularization of this solution. Thus, this study aims to evaluate the use of low cost systems to perform 3D scanning in the context of custom orthoses development for wrist, hand and fingers to be fabricated by additive manufacturing. A three-phases method was proposed as follows: definition of tools and systems to be evaluated, definition of parameters for assessment, and definition of protocols for using 3D scanning systems; evaluation of low-cost 3D scanning systems using a standard piece; and evaluation of low-cost 3D scanning systems applied to context of orthosis for wrist, hand and fingers. The selected systems for the evaluation were 360 Kinect using Skanect software, Kinect One system with 3DScan software and the ReMake system with a Canon T3i camera. The low-cost 3D scanning systems used protocols were: Protocol 1, with visual markings only on the scanning environment; Protocol 2, with colored stickers application on the object; and protocol 3, with the use of hand drawn lines forming a chess pattern on the object. A standard piece was developed and manufactured, composed of three elements (a cone, a cylinder and a sectioned cube). The cone height, cylinder diameter and parallel measures to axes X, Y and Z were considered as the dimensional evaluation parameters. Also, a Deviations Analysis was performed using Geomagic software and a visual-quality evaluation that observed the formation of vertices and edges. For the evaluation on orthoses development context, the same procedure was applied on a cast of the wrist, hand and fingers. This cast was made of plaster bandages. The procedure generated 27 standard piece 3D mesh and 9 cast 3D meshes. The evaluations indicated that Kinect 360 and Kinect One systems have no significant variation between the different protocols. The ReMake system was the most sensitive, and the protocol 3 generated 3D meshes with the best dimensional and quality results among all systems. The deviations analysis performed on the standard piece indicated errors ranging between 0.07 mm and 0.27 mm for the ReMake’s 3D meshes.