Superficial Characteristics of Acetone Vapor Treated ABS Printed Parts for Use in Upper Limb Prosthesis

Abstract

Approximately 33% of amputations happen due to external causes, which makes these patients strong candidates for prostheses use. Nevertheless, functional hand prostheses are expensive, costing more than R$ 30,000.00, and are not very accessible, especially in Brazil. Trying to reduce their cost, several groups around the world have been researching the construction of prostheses using additive manufacturing (AM). The most common AM technique is Fused Deposition Modeling (FDM), also known as 3D printing. A heated polymer filament is forced trough a nozzle, and placed in the right position, layer upon layer, until the piece is complete. It is possible to improve surface quality of 3D printed parts by using post processing techniques. Dealing with parts made of Acrylonitrile Butadiene Styrene (ABS), acetone vapor bath is an adequate choice of treatment. Pieces printed in different orientations were treated with acetone vapor for different times, and then submitted to nanoindentation tests and topography and roughness analysis in an Optical Profiler. A reduction in hardness and elastic modulus was observed after treatment. Roughness was also drastically reduced, and staircase effect was eliminated after treatment. It is important to consider the application of printed piece before applying acetone vapor bath, as the process alters external measures and mechanical properties. For future work, it is intended to analyze if the reduction in mechanical superficial properties impacts the use of printed parts in upper limb functional prosthesis.