Fabrication and stress analysis of ankle foot orthosis with additive manufacturing

Abstract

Purpose

Ankle–foot orthoses (AFOs) are assistive devices prescribed for a number of physical and neurological disorders affecting the mobility of the lower limbs. Additive manufacturing has been explored as an alternative process; however, it has proved to be inefficient cost-wise. This work aims to explore the possibilities of generating modular AFO elements, namely, calf, shank and footplate, with the localized composite reinforcement that aids in the optimization of the device in terms of functionality, aesthetics, rigidity and cost.

Design/methodology/approach

The conventional lower leg–foot orthosis configuration depends on thermoforming a polymer sheet around a mortar cast with a trademark firmness relying upon the trim-line with the inalienable plan restrictions. In manufacturing of AFO the expert, i.e. orthotist's, guidance is used. Polypropylene and polyethylene material is used in fabrication of AFO to complete all-round reported points of interest over the ordinary outlines, yet their mechanical conduct under administration conditions cannot be effectively anticipated.

Findings

AFOs made of polypropylene and polyethylene material are available in the market, which are used by children of age 3-5 years. With the existing AFO design, patients are facing excessive heating and sweating problems during long-term usage. After feedback from patients and orthotists (who prescribed AFO to patients), an attempt has been made to solve the problem with a new and improved AFO design of AFO by using finite element modelling and stress analysis. Also, the results indicate that the new design is similar to the actual product design.

Originality/value

This work introduces the low-cost 3D printing with reinforcement approach as an alternative route for the designing and manufacturing of orthotic devices with complex shapes. It is expected that new applications add-up to increase the body of knowledge about the behaviour of such products which will mix both areas, composite theory and additive manufacturing. This study investigated the fields related to 3D scanning, 3D printing and computer-aided designing for the manufacturing of a customized AFO.

Citation

Banga, H.K., Belokar, R.M., Kalra, P. and Kumar, R. (2018), "Fabrication and stress analysis of ankle foot orthosis with additive manufacturing", Rapid Prototyping Journal, Vol. 24 No. 2, pp. 301-312. https://doi.org/10.1108/RPJ-08-2016-0125