This work focuses on optimizing the mechanical and electromechanical properties of a 3D-printed strain-sensing prosthetic socket fabricated using a conductive PETG-based composite (P15LT35 G) via Fused Deposition Modelling (FDM). A full factorial design (33) was implemented to study the influence of nozzle diameter (0.4, 0.5, 0.6 mm), infill pattern (grid, lines, gyroid), and infill density (30%, 50%, 70%) on performance characteristics. The socket was evaluated through tensile, flexural, impact, and compression testing, with the best configuration (0.4 mm nozzle, grid pattern, 70% infill) yielding a peak compressive strength of 25.62 MPa and a flexural strength of 31.72 MPa. Electrical characterization revealed that the optimized sensor exhibited a gauge factor of 1.52 with a nonlinearity coefficient of 4.01 under cyclic loading, indicating stable piezoresistive behavior. The low sensitivity, denoting controlled resistance changes under uniform loading, enhances signal reliability for limb-socket interface monitoring. ANOVA and Response Surface Methodology (RSM) were used to develop predictive models with high significance (p < .05) and adjusted R2 values exceeding 95%. The final prosthetic socket design includes embedded sensor paths and ventilation zones, validated through load simulations and experimental tests. The study demonstrates a robust approach for integrating sensing capability within structural components, offering a scalable solution for smart prosthetic systems.
LathouwersEDíazMAMaricotA, et al.Therapeutic benefits of lower limb prostheses: a systematic review. J NeuroEng Rehabil2023; 20: 1–27.
2.
SinhaRVan Den HeuvelWJAArokiasamyP. Factors affecting quality of life in lower limb amputees. Prosthet Orthot Int2011; 35: 90–96.
3.
EngsbergJRSprouseSWUhrichML, et al.Comparison of rectified and unrectified sockets for transtibial amputees. J Prosthet Orthot2006; 18: 1–7.
4.
Mendaza-DeCalRPeso-FernandezSRodriguez-QuirosJ. Orthotics and prosthetics by 3d-printing: accelerating its fabrication flow. Res Vet Sci; 162: 104960.
5.
Pavan KalyanBKumarL. 3D printing: applications in tissue engineering, medical devices, and drug delivery. AAPS PharmSciTech2022; 23: 92.
6.
LestariWDAdyonoNFaizinAK, et al.Optimization of 3D printed parameters for socket prosthetic manufacturing using the taguchi method and response surface methodology. Results Eng; 21: 101847.
7.
RamleeMHAmmarullahMIMohd SukriNS, et al.Investigation on three-dimensional printed prosthetics leg sockets coated with different reinforcement materials: analysis on mechanical strength and microstructural. Sci Rep2024; 14(1): 6842.
8.
BeygiHBWongMS. Contemporary and future development of 3D printing technology in the field of assistive technology, orthotics and prosthetics. Can Prosthetics Orthot J2023; 6: 42225.
9.
PopişterF. Experimental study of comprehensive performance analysis regarding the dynamical/mechanical aspects of 3D-printed UAV propellers and sound footprint. Polymers2025; 17: 1466.
10.
KumarSAdvances in additive manufacturing volume — I. 2023.
11.
RajATyagiBSharmaGS, et al.Optimizing the process parameters with statistical and soft computing techniques for enhanced mechanical properties of acrylonitrile butadiene styrene material samples fabricated via fused filament fabrication technique. Prog Addit Manuf2024; 10: 2559–2583.
12.
RajAChandrakarASTyagiB, et al. Advancements in material extrusion based three-dimensional printing of sensors: a review. Int J Interact Des Manuf. 2024; 18(1): 627–648.
13.
RajATyagiBKapoorA, et al.Exploring additive manufacturing parameters for improved tensile strength and functional electrode fabrication. Nature-inspired Metaheuristic Algorithms. Boca Raton: CRC Press, pp. 257–283.
14.
RajATyagiBJainA, et al.Using annealing to improve the mechanical properties of 3D-printed PLA parts: an experimental investigation, pp. 125–136.
15.
RajATyagiBGoyalA, et al.Comparing the predictability of soft computing and statistical techniques for the prediction of tensile strength of additively manufactured carbon fiber polylactic acid parts. J Mater Eng Perform2023; 33: 12729–12741.
16.
SinghRSinghGSinghJ, et al.Investigations for tensile, compressive and morphological properties of 3D printed functional prototypes of PLA-PEKK-HAp-CS. J Thermoplast Compos Mater2021; 34: 1408–1427.
17.
UlkirOAkgunG. Fuzzy logic and taguchi approach for compressive strength prediction of ABS components fabricated by AM. J Thermoplast Compos Mater2025.
18.
NingF. Additive manufacturing of carbon fiber-reinforced plastic composites using fused deposition modeling : effects of. J Compos Mater2016; 0: 1–12.
19.
Dp-IJEDR. Effects of infill patterns on time, surface roughness and tensile strength in 3D printing. rjwave.orgDM PatelInt J Eng Dev Res, 2017•rjwave.org2017; 5. https://rjwave.org/ijedr/papers/IJEDR1703083.pdf
20.
VigneshMRanjith KumarGSathishkumarM, et al.Development of biomedical implants through additive manufacturing: a review. J Mater Eng Perform2021; 30: 4735–4744.
21.
DikicierS. Additive manufacturıng techniques used in prosthetic treatments. International Journal of Oral and Dental Health. 2024; 10: 163.
22.
TyagiBRajASharmaGS, et al.Enhancing performance and reliability: investigating failure morphology and statistical analysis of reinforced polylactic acid for application of transtibial prosthetic socket. Polym Bull2025; 82: 4711–4738.
23.
BajpaiPKSinghIMadaanJ. Development and characterization of PLA-based green composites: a review. J Thermoplast Compos Mater2014; 27: 52–81.
24.
BarhateARGangadharSABhandariAJ, et al.Materials used in maxillofacial prosthesis: a review. Pravara Med Rev2015; 7: 5–8.
25.
ShuxianZWanhuaZBinghengL. 3D reconstruction of the structure of a residual limb for customising the design of a prosthetic socket. Med Eng Phys2005; 27: 67–74.
26.
KumarN. Parametric optimization and design validation based on finite element analysis of hybrid socket adapter for transfemoral prosthetic knee. Prosthet Orthot Int2014; 38: 363–368.
27.
NayakCSinghAChaudharyH, et al.A novel approach for customized prosthetic socket design. Biomed Eng Appl Basis Commun2016; 28: 1650022.
28.
IonescuRNTotanARImreMM, et al.Prosthetic materials used for implant-supported restorations and their biochemical oral interactions: a narrative review. Materials; 15(3): 1016.
29.
AryalMRPunS. Additive manufacturing of prosthetic hands: a brief overview. Int J Interact Des Manuf2022; 16: 1099–1112.
30.
TyagiBRajASahaiA, et al.Enhancing compressive strength in polymer composites utilized for application of foot prostheses. J Polym Res 2024; 31(2): 30.
31.
SachinBRaoCMKumarNK, et al.Design and fabrication strategies for enhancing patient comfort and sustainability through PETG based 3D-printed orthoses. Prog Addit Manuf2025; 10: 5937–5956.
32.
MishraVNegiSKarS, et al.Recent advances in fused deposition modeling based additive manufacturing of thermoplastic composite structures: a review. J Thermoplast Compos Mater2023; 36: 3094–3132.
33.
Sakthi BalanGAravind RajS. Effect of additives on the performance of extruded polymer composites: a comprehensive review. J Thermoplast Compos Mater2025; 38: 810–853.
34.
BediSSMalleshaVMaheshV, et al.Investigation of low-percentage graphene reinforcement on the mechanical behaviour of additively manufactured polyethylene terephthalate glycol composites. J Thermoplast Compos Mater2024; 37: 910–930.
35.
KaradagAUlkirO. Prediction of dimensional accuracy and surface quality in additively manufactured biomedical implants using ANN. Int J Precis Eng Manuf2025; 26: 1187–1213.
36.
GunesSUlkirOKuncanM. Modelling and fabrication of flexible strain sensor using the 3D printing technology. J Thermoplast Compos Mater2025; 38: 1724–1743.
