Designing the Structure of and a Fabrication Process for a Corrective Insole in CAD/CAE/CAM Systems

Abstract

This paper presents the results of our research into improving the design and fabrication quality of custom-molded corrective insoles by developing modern computer-aided modeling and programming methods that factor in changes in the mechanical properties of materials during use. This paper proposes a method for designing custom corrective insoles using the optimal insole structure and material. We used OrthoModel to design an insole model in a solid-body format and then exported it as an STL file. Then, using FreeCAD, we converted the STL file to a STEP file to better adapt the model for further use and analysis. Using the Ansys environment, we devised a finite element model for insole deformation and investigated the behavior exhibited by the material of the insole arch under different loads and combinations of EVA materials with varying hardness. The model yielded the stresses and deformations experienced by the insole arch during use, depending on the combination of the material and the geometry of the foot, and those stresses and deformations were experimentally verified. The calculated values for insole deformation served as input for programming the processing of the insole with a CNC machine. With a 3D insole model, it is possible to both fabricate the insole with a CNC machine and to print the insole with a 3D printer. The calculated cost price of fabricating custom-molded corrective insoles attests to the competitiveness of the proposed technique.

Experimental Analysis of Corrective Insoles Materials

“…CAD/CAM technologies and rapid prototyping technologies were currently the most important tools in improving the conception and manufacturing processes. [ 4 ] CAD/CAM technology for manufacturing personalized insoles consisted of the orthotic device design method upon the scanned model of the limb and creating a program for processing the device using a CNC machine. The disadvantage of this method was the production time and the requirement of a specialized person in CAD/CAM technologies.…”