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PROSTHETICS & ORTHOTICS JOURNAL, VOLUME 1, ISSUE 2, 2018; ABSTRACT, POSTER PRESENTATION AT THE AOPA’S 101ST NATIONAL ASSEMBLY, SEPT. 26-29, VANCOUVER, 
CANADA, 2018.   DOI: https://doi.org/10.33137/cpoj.v1i2.32038                                                                     

1 

 
OPEN  ACCESS 

 

AOPA’S 101 ST NATIONAL ASSEMBLY ABSTRACTS, SEPTEMBER 26-29, VANCOUVER, CANADA, 2018 
 

ABSTRACT (POSTER PRESENTATION) 

HOW INFILL PERCENTAGE AFFECTS THE ULTIMATE STRENGTH OF A 3D-

PRINTED TRANSTIBIAL SOCKET 

Leah Campbell1, Adriel Lau*1, Brittany Pousett2, Ernie Janzen3, Silvia U Raschke3 

1 Prosthetics and Orthotics, School of Health Sciences, British Columbia Institute of Technology (BCIT), Burnaby, British                             

Columbia, Canada. 
2 Barber Prosthetics Clinic, Vancouver, British Columbia, Canada. 
3 MAKE + Applied Research, Centre for Applied Research & Innovation (CARI), Burnaby, British Columbia, Canada.  
 
*  Email: lau.adriel@gmail.com                                                                                   DOI: https://doi.org/10.33137/cpoj.v1i2.32038  

 

INTRODUCTION 

3D printing for non‐weight‐bearing upper extremity 

prostheses is becoming increasingly popular as a  

method of fabrication.1 Some clinics in North America 

have begun using 3D printing to fabricate lower 

extremity diagnostic sockets (Figure 1). The strength 

requirements for upper extremity prostheses are not as 

rigorous as the strength requirements for lower extremity 

prostheses. Therefore, strength testing on 3D-printed 

lower extremity sockets is one of the first steps that needs 

to be conducted to ensure patient safety. 3D-printed 

prosthetic sockets are becoming an alternative option to 

traditional methods because it is possible to customize 

different parameters to create a strong structure. Infill 

percentage is an important parameter to research as this 

can have an influence on the strength of 3D printed 

sockets.2 As both prosthetists and healthcare 

professionals, there is a need to become more involved 

in the process of designing and testing 3D printed 

sockets. The purpose of this study is to test how changing 

the infill percentage affects the ultimate strength of a 3D 

printed transtibial socket during initial contact. 

 

 

 

 

 

 

 

METHODS 

A total of nine transtibial sockets were printed using a 

Fused Deposition Modeling (FDM) printer. Three 

different infill percentages were chosen because they 

represent realistic percentages that clinicians may decide 

to print. Three sockets were printed at 30% infill, three 

sockets at 40% infill and three sockets at 50% infill. All 

the sockets were printed from a white polylactic acid 

(PLA) filament and from the same data file to maintain 

shape consistency (Table 1). The sockets were tested for 

ultimate strength in a Tinius Olsen universal testing 

machine (Figure 2) located at the British Columbia 

Institute of Technology. The International Organization 

for Standardization (ISO) standard 10328 outlines the 

process and procedures of structural testing in lower limb 

prostheses.3 The standard determines whether the sockets 

can withstand the minimum static load at initial contact 

and how much additional load it can withstand. 

 
Table 1. Characteristics of the 3D-Printed sockets before 

structural tests. 

 

 

RESULTS 

In all nine sockets, the amount of force that resulted in 

socket failure exceeded the ISO 10328 threshold of 

4480N (Figure 3). The infill percentages (30% - 50%) do 

not appear to impact the ultimate strength of the socket. 

Observational analysis of socket failure show that all 

sockets broke in two areas: 1) lateral mid socket  or 2) 

medial popliteal area with the latter region being the most 

common.  

Figure 1. 3D printed 

transtibial socket 

Figure 2. Testing 

jig with socket. 

https://doi.org/10.33137/cpoj.v1i2.32038
mailto:lau.adriel@gmail.com
https://doi.org/10.33137/cpoj.v1i2.32038


 

 

Campbell L, Lau A, Pousett B, Janzen E, Raschke S.U.  HOW INFILL PERCENTAGE AFFECTS THE ULTIMATE STRENGTH OF A 3D-PRINTED TRANSTIBIAL SOCKET. CANADIAN 

PROSTHETICS & ORTHOTICS JOURNAL, VOLUME 1, ISSUE 2, 2018; ABSTRACT, POSTER PRESENTATION AT THE AOPA’S 101ST NATIONAL ASSEMBLY, SEPT. 26-29, VANCOUVER, 
CANADA, 2018.   DOI: https://doi.org/10.33137/cpoj.v1i2.32038                                                                     

2 

 
OPEN  ACCESS 

 

AOPA’S 101 ST NATIONAL ASSEMBLY ABSTRACTS, SEPTEMBER 26-29, VANCOUVER, CANADA, 2018 
 

ABSTRACT (POSTER PRESENTATION) 

 

 
Figure 3. Force of failure of 3D Printed transtibial sockets. 

Horizontal line represents the strength threshold set by ISO 

Standard 10328 (4480N). 

 
Table 2. Areas of socket failure and failure types 

 
 

 

 

CONCLUSION 

3D printing technology is currently being used in many 

different industries. The field of prosthetics and orthotics 

needs to demonstrate how it can successfully use the 

technology in clinical practice. A logical first step is 

testing the strength of 3D-printed prosthetic sockets to 

determine if it is safe for patient use. Using the specific 

criteria (static testing, initial contact and P5 weight class) 

and procedures of ISO Standard 10328, this research 

project demonstrated that the ultimate strength of the 3D-

printed sockets exceeded the minimum required 4480N 

threshold set by the standard. Furthermore, infill 

percentages ranging from 30% to 50% did not seem to 

affect the ultimate strength of the sockets. 

FUTURE DIRECTIONS 

This project focused on specific conditions whereas the 

standard outlines additional conditions.3 It is important 

that these other conditions are tested to fully deem a 3D 

printed socket safe for patient use. 3D printing 

technology is advancing quickly. It would be beneficial 

to investigate how different printers, materials, and 

methods of printing can affect the strength of a socket. 

Further research should test multiple parameters (e.g. 

layer height and wall thickness) to see their combined 

effect on the strength of a prosthetic socket. This project 

is a small part of a much larger research initiative 

involving collaboration among clinicians and 

technicians. The hope is that the findings from this 

project contribute to the understanding and awareness of 

3D printing in the Prosthetics and Orthotics field. 

REFERENCES 

1. Chhaya M.P, Poh P.S, Balmayor E.R, Griensven M, Schantz 

J.T, Hutmacher D.W.  Additive manufacturing in biomedical 

sciences and the need for definitions and norms. Expert 

Review of Medical Devices. 2015; 12(5), 537–543. 

DOI:10.1586/17434440.2015.1059274 

2. Johansson F. Optimizing fused filament fabrication 3D 

printing for durability: Tensile properties and layer bonding 

(Dissertation). 2016; Retrieved from: 

http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12355 

3.International Organization for Standardization. (2006). 

Prosthetics - Structural testing of lower limb prostheses - 

Requirements and test methods (ISO 10328). 

ACKNOWLEDGMENT 

Barber Prosthetics Clinic 

• Dave Moe, CP(c) 

• Daryl Murphy, RTP(c) 

• Brittany Pousett, M.Sc., CP(c) 

• Malena Rapaport, M.Sc., CP(c) 

Additive O&P 

Ernie Janzen, Lab Coordinator 

Lynn Erickson, Ph.D., P.Eng. 

Nathan Devos, Ph.D. 

Caroline Soo, M.Sc. 

 

Figure 4. Socket broken 

in the medial popliteal 

area. 

Figure 5. Socket broken 

in the middle lateral area. 

https://doi.org/10.33137/cpoj.v1i2.32038
http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12355

