Investigative Study of 3D Printed Connectors in Volvo Trucks production A Comparison of Methods and Materials Master’s thesis in Applied Mechanics LINNEA PIHL DEPARTMENT OF MECHANICS AND MARITIME SCIENCES CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden 2025 www.chalmers.se www.chalmers.se Master’s thesis 2025 Investigative Study of 3D Printed Connectors in Volvo Trucks production A Comparison of Methods and Materials LINNEA PIHL Department of Mechanics and Maritime sciences Chalmers University of Technology Gothenburg, Sweden 2025 Investigative Study of 3D Printed Connectors in Volvo Trucks production A Comparison of Methods and Materials LINNEA PIHL © LINNEA PIHL, 2025. Supervisor: Richard Ernfjäll, Volvo AB Examiner: Ragnar Larsson, Industrial and Materials Science Master’s Thesis 2025 Department of Mechanics and Maritime Sciences Chalmers University of Technology SE-412 96 Gothenburg Telephone +46 31 772 1000 Cover: Finite Element simulation of connector analyzed in this thesis work. Typeset in LATEX, template by Kyriaki Antoniadou-Plytaria Printed by Chalmers Reproservice Gothenburg, Sweden 2025 iv Investigative Study of 3D Printed Connectors in Volvo Trucks production A Comparison of Methods and Materials LINNEA PIHL Department of Mechanics and Maritime Sciences Chalmers University of Technology Abstract All vehicles that are produced today by Volvo are provided with software that con- trols the vehicle. In Volvo Trucks production facilities, connectors are used to down- load software to the vehicle by using connectors. This master thesis is carried out together with Volvo group AB and aims to conduct an investigative study to evalu- ate whether the connectors used could be 3D printed, used as spare parts and used in Volvo’s production. To analyze whether it is feasible to use a 3D printed connec- tor in production, a material study was carried out, and a finite element analysis was performed on both existing and 3D printed connectors. The material study included tensile testing of the following polymer materials: Sustarine, PLA, PLA- CF, PETG, PETG-CF, TPU, and PATH-CF. In addition to tensile testing, the 3D printed test samples were also observed for surface quality and dimensional accuracy. From the material study, it was found that the PLA, PLA-CF, PETG and PETG- CF materials were suitable to print connectors in. PATH-CF was excluded due to challenges in achieving acceptable print settings and the poor surface quality it produced, and TPU was excluded due to issues such as deformation in corners and holes and insufficient layer bonding. From the finite element analysis it could be seen that all materials except TPU could be suitable to print the connectors. The TPU material was unsuitable because it was the only material in which the von Mises stress exceeded the material’s yield strength. The results indicate that it would be possible to use a 3D printed connector as a spare part. To be able to know if a 3D printed connector could have completely replaced a purchased connector, more studies would have needed to be done, such as fatigue analysis and material wear. Keywords: 3D printing, Finite element analysis (FEA), PLA, PLA-CF, PETG, PETG-CF, TPU, PATH-CF v Acknowledgements I would like to express my sincere gratitude to everyone who has supported and encouraged me throughout the course of this thesis work. First and foremost, I would like to extend my heartfelt thanks to Volvo Group AB, the ESW Tools, Systems & Strategy Group and my industrial supervisor Richard Ernfjäll for their generous support, valuable insights, and continuous guidance dur- ing this project. Your expertise and feedback were instrumental in helping me navigate challenges and complete the work successfully. I am also deeply grateful to my academic supervisor and examiner at Chalmers, Ragnar Larsson, for his academic guidence, constructive critique, and consistent support throughout the process. Your academic perspective helped me improve the quality of the thesis work. Finally, I would like to thank my family for their encouragement and support, whose support has been truly invaluable throughout this process. Linnea Pihl, Gothenburg, June 2025 vii List of Acronyms Below is the list of acronyms that have been used throughout this thesis listed in : ABS Acrylonitrile Butadiene Styrene AM Additive manufacturing DOF Degrees of freedom ECUs Electric control units FEA Finite Element Analysis FEM Finite Element Method G-code Code generated by slicer PLA Polylactic Acid PLA-CF Carbon fiber reinforced PLA PETG Polyethylene Terephthalate Glycol PETG-CF Carbon fiber reinforced PETG PATH-CF Carbon fiber reinforced Nylon 12 TPU Thermoplastic Polyurethane ix Contents List of Acronyms ix List of Figures xiii List of Tables xv 1 Introduction 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.4 Problem formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.5 Use of artificial intelligence . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Theory 5 2.1 Selected connector and load case . . . . . . . . . . . . . . . . . . . . 5 2.2 Finite Element Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 3D Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4.1 PLA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4.2 PETG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4.3 TPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4.4 PATH-CF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4.5 Sustarine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.5 Sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Methods 11 3.1 Material investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.1 Poisson’s ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.2 3D printing test specimens . . . . . . . . . . . . . . . . . . . . 11 3.1.3 Tensile testing on test specimens . . . . . . . . . . . . . . . . 12 3.1.4 3D printing connectors . . . . . . . . . . . . . . . . . . . . . . 13 3.2 Tensile test purchased connector . . . . . . . . . . . . . . . . . . . . . 14 3.3 Finite Element Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 15 4 Results 21 4.1 Material investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.2 Tensile test purchased connector . . . . . . . . . . . . . . . . . . . . . 23 xi Contents 4.3 Finite Element analysis results . . . . . . . . . . . . . . . . . . . . . . 24 4.3.1 Mesh sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.3.2 FEA results purchased connector . . . . . . . . . . . . . . . . 25 4.3.3 Finite Element Analysis results 3D printed connectors . . . . . 26 5 Discussion and Conclusion 31 5.1 Material data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.2 3D printing and materials . . . . . . . . . . . . . . . . . . . . . . . . 31 5.3 Finite Element Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.4 Sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.5 Fulfillment of aim and goals . . . . . . . . . . . . . . . . . . . . . . . 33 5.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Bibliography 35 A Appendix 1 I .1 3D-print settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I .1.1 PLA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I .1.2 PLA-CF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II .1.3 PETG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III .1.4 PETG-CF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV .1.5 TPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V .1.6 PATH-CF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VI .2 CAD drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VII .3 Tensile test purchased connector . . . . . . . . . . . . . . . . . . . . . VII .4 Figures simulated connector . . . . . . . . . . . . . . . . . . . . . . . XVII xii List of Figures 1.1 Connector studied in this thesis project. . . . . . . . . . . . . . . . . 1 2.1 Drawing of the connector provided by Volvo Trucks. . . . . . . . . . . 5 2.2 Catia model of how the parts of the connector fit together. . . . . . . 6 3.1 Test specimens in slicer program. . . . . . . . . . . . . . . . . . . . . 12 3.2 Drawing and complete test specimen in Catia V5. . . . . . . . . . . . 12 3.3 Test setup for 3D printed test specimens. . . . . . . . . . . . . . . . . 13 3.4 Part one of the connector housings orientation in slicer. . . . . . . . . 13 3.5 Second part of the connector housings orientation in slicer. . . . . . . 14 3.6 Orientation of the clams in slicer. . . . . . . . . . . . . . . . . . . . . 14 3.7 Tensile test setup of the purchased connector. . . . . . . . . . . . . . 15 3.8 Rigid connection between the first and second parts of the connector housing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.9 Rigid connection between cable glamp and the back part of the con- nector housing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.10 Rigid connection between the shaft and connector housing. . . . . . . 17 3.11 Rigid connection between the shaft and clams. . . . . . . . . . . . . . 17 3.12 Contact connection between the connector housing and clams. . . . . 18 3.13 Clamped boundary condition. . . . . . . . . . . . . . . . . . . . . . . 18 3.14 Distributed force boundary condition. . . . . . . . . . . . . . . . . . . 19 3.15 Selected surfaces where a local mesh was added are highlighted orange. 20 4.1 Surface printing results for PLA, PETG, PLA-CF and PETG-CF. . . 22 4.2 Observed issues from printed TPU, (a) deformation in corners and holes, and (b) insufficient layer bonding. . . . . . . . . . . . . . . . . 23 4.3 Surface of a 3D printed test specimen in PATH-CF. . . . . . . . . . . 23 4.4 Force versus pull-out displacement required for the connector to de- tach from the adapter. . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.5 Comparison between a local mesh of 2,1,0.5,0.25 mm respectivaly. . . 25 4.6 Result of FEA simulation of the purchased connectorfrom the side. . 26 4.7 Result of FEA simulation of the purchased connector from above. . . 26 4.8 FEA simulations for the 3D printed materials. . . . . . . . . . . . . . 28 4.9 FEA simulations for the 3D printed materials with metal clams. . . . 29 .1 3D print settings for PLA. . . . . . . . . . . . . . . . . . . . . . . . . I .2 3D print settings for PLA-CF. . . . . . . . . . . . . . . . . . . . . . . II xiii List of Figures .3 3D print settings for PETG. . . . . . . . . . . . . . . . . . . . . . . . III .4 3D print settings for PETG-CF. . . . . . . . . . . . . . . . . . . . . . IV .5 3D print settings for TPU. . . . . . . . . . . . . . . . . . . . . . . . . V .6 3D print settings for PATH-CF. . . . . . . . . . . . . . . . . . . . . . VI .7 CAD drawing of test specimen. . . . . . . . . . . . . . . . . . . . . . VII .8 Connector in PLA . . . . . . . . . . . . . . . . . . . . . . . . . . . . XVII .9 Connector in PLA-CF . . . . . . . . . . . . . . . . . . . . . . . . . . XVII .10 Connector in PETG . . . . . . . . . . . . . . . . . . . . . . . . . . . XVIII .11 Connector in PETG-CF . . . . . . . . . . . . . . . . . . . . . . . . . XVIII .12 Connector in TPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIX .13 Connector in PATH-CF . . . . . . . . . . . . . . . . . . . . . . . . . XIX .14 Connector in PLA except the clams. . . . . . . . . . . . . . . . . . . XX .15 Connector in PLA-CF except the clams. . . . . . . . . . . . . . . . . XX .16 Connector in PETG except the clams. . . . . . . . . . . . . . . . . . XXI .17 Connector in PETG-CF except the clams. . . . . . . . . . . . . . . . XXI .18 Connector in TPU except the clams. . . . . . . . . . . . . . . . . . . XXII .19 Connector in PATH-CF except the clams. . . . . . . . . . . . . . . . XXII xiv List of Tables 2.1 Material data for PLA and PLA-CF from the manufacturer. . . . . . 9 2.2 Material data for PETG and PETG-CF from the manufacturer. . . . 9 2.3 Material data for PATH-CF from the manufacturer. . . . . . . . . . . 9 2.4 Material data for Sustarine from the manufacturer. . . . . . . . . . . 10 3.1 Material data used during FEA simulations. . . . . . . . . . . . . . . 16 4.1 Material data from tensile testing 3D printed test specimens. . . . . . 21 4.2 Mesh sensitivity analysis showing von Mises stress for different local mesh sizes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4.3 von Mises stress results from simulating the different 3D printed ma- terials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 xv List of Tables xvi 1 Introduction This chapter presents the background necessary to understand why the thesis is carried out. The chapter also presents the aim and limitations of the project, as well as the use of artificial intelligence. 1.1 Background All vehicles produced today by Volvo trucks are provided with software that con- trols many of the different features and functions in the vehicle. For example, a window goes down when pressing a button, or a warning goes off if one is driving without the seatbelt. These different functions are managed by small computers called electronic control units (ECUs), which are placed at several different places on the truck. During production, connectors are used to connect to the different ECUs, to download softwareto the vehicle. This is done in multiple places on the production line and in different parts of the vehicle. These different vehicle parts need different types of connectors. The connectors are designed and manufactured by other companies and then purchased by Volvo. Volvo decides on what functions and properties that are needed, and the company manufactures a prototype that Volvo evaluates. Figure 1.1: Connector studied in this thesis project. 1 1. Introduction It is an iterative process in which Volvo and the company send the prototype back and forth until Volvo is satisfied with the product. The connector that will be studied in this thesis, see Figure 1.1, is used at a sub-assemblage station for engine assembly. The connector is fixed at a software download station and the vehicle is attached to the production line that constantly moves forward. 1.2 Aim The purpose of this thesis is to conduct an investigative study to evaluate whether it is possible to 3D print connectors in Volvo trucks production facilities that can be used in the factory as spare parts or as replacement of existing connectors, and if it is feasible to use 3D printed connectors during prototype testing and validation. Investigate whether FEM analysis can be used reliably on 3D printed materials and to identify possible error sources and limitations using 3D printed connectors. The aim of the thesis is to support the company in the decision-making process around 3D printing as a manufacturing method for spare parts or parts used in production, which can contribute to a more efficient development process, reduced costs, and improved environmental impact. 1.3 Limitations The following limitations are set on this project: 1. The digital model will be simplified to contain no screws, springs, or pins. 2. The thesis will not include lateral loads. 3. The materials that the study will examine are PLA, PLA-CF, PETG, PETG- CF, TPU95A, PATH-CF 4. There will be no comparison between different 3D printers. 5. There will be no comparison between different infill percentages or infill struc- tures. 6. The study is limited to being conducted for 20 weeks. 1.4 Problem formulation To clarify and simplify the main problem, the thesis is divided into different problem areas. The problem areas were then divided into different sub-objectives that should be met in order to carry out the work. 1. Examine which material is suitable for 3D printed connectors through tensile testing, property testing, ease of printing, and physical results of printing. 2. Investigate which parts of the connector that is suitable for 3D printing. 3. What type of load case should be investigated? 4. Investigate 3D printed connectors during the selected load case by performing finite element analysis and physical testing. 5. Examine if the finite element analysis matches the physical testing of the 3D printed connectors in the different materials. 2 1. Introduction 6. Compare the results between machined and 3D printed connectors based on the stresses that occur during the selected loadcase. 7. How does the chosen material and 3D printing as a manufacturing method affect the environment compared to the machined connector? 1.5 Use of artificial intelligence When it comes to using artificial intelligence (AI) tools, it is important to be aware of the risks involved. According to Chalmers guidelines, the student must use AI in a responsible and transparent manner [7]. The student must assume full responsibility and be able to justify the content and choices made, as well as clearly show what and how AI has been used. In this work, AI has not been used to make decisions, develop methods and results, or generate text. AI has been used as a tool to troubleshoot the 3D printer, find where certain specific settings are in the slicer software, and provide suggestions for improvements and wording in the report. 3 1. Introduction 4 2 Theory In this chapter, all relevant theory will be presented. This includes the theory of the selected connector, the selected load case, 3D printing, finite element analysis, and materials. 2.1 Selected connector and load case As described in Background 1.1, the connector is used in the production of Volvo Trucks. The connector is fixed at a station where an operator connects it to the sub-module that will be programmed with software. The part of the vehicle that will be programmed is constantly moving on the production line. The case that will be studied in this project is an event in which the operator forgets to disconnect the connector from the adapter in time, and the sub-assembly continues to move while still attached to the connector. The connector will then be exposed to a force and the case is to investigate what force the current machined connectors can withstand and what force a 3D printed connector printed in the factory could withstand. Figure 2.1: Drawing of the connector provided by Volvo Trucks. The connector consists of two main parts that are screwed together with metal screws, two clamps that are attached via a metal shaft, and a cable gland that stabilizes the cord. In the connector, there are also two springs per clamp. A 5 2. Theory drawing of the connector can be seen in Figure 2.1 and how the different parts are put together can be seen in Figure 2.2. (a) (b) Figure 2.2: Catia model of how the parts of the connector fit together. 2.2 Finite Element Analysis The Finite element method (FEM) is a numerical method used to solve partial dif- ferential equations by dividing a complex geometry into smaller simpler parts called finite elements. Instead of solving the differential equation for the entire domain, FEM approximates the solution within each finite element. This makes it possible to approximate solutions to problems that would be difficult to analyze analytically. [2]. The points where elements are connected to each other are called nodes, and each node has an associated set of degrees of freedom (DOF). Using the DOFs of the nodes together with predefined equations, the behavior of each element can be determined based on known material properties. This process is performed on all elements, resulting in an approximate solution for the entire domain. Finite element analysis (FEA) is the practical application of FEM. The first step to performing an FEA analysis is mesh generation of the object which will be analyzed. When a mesh is generated, the geometry of the object is divided into finite elements. The mesh size (size of the elements) will determine the accuracy of the solution. A main rule is that a finer mesh with smaller elements gives a more exact solution, but also requires more computing resources and takes longer time to simulate. To avoid performing simulations that take an unnecessary long time, it is common to perform a mesh sensitivity study to determine when convergence of the results is reached. A mesh sensitivity study aims to establish the optimal mesh configuration. This is done by systematically changing the mesh size and observing the solution. When the solution result does not change more than the intended accuracy, the solution can be considered to be converged. If the geometry which will be simulated is complex or has, for example, a small radius, a local mesh size can be applied, which means that meshing is only refined where necessary. The chosen material is defined in the FEA software. When a polymeric material is modeled, properties such as density and elasticity are needed. These properties 6 2. Theory include Young’s modulus(E), Poisson’s ratio (ν), yield stresses (σy) and density (ρ). These properties can be obtained by either using existing data sheets or analyzing stress-strain curves extracted from material testing data. 2.3 3D Printing Additive manufacturing (AM) is a technology that is capable of creating physical 3D objects from a digital model. An AM method is 3D printing, where the digi- tal model is broken down into 2D cross sections, called layers, by using a program called a slicer. The slicer software then generates a G-code that can be sent to the 3D printer. Using the G-code, the 3D printer can create the physical object by a layer-by-layer sequence. The 3D printer melts the material and extrudes the melted material through a nozzle in the layers generated by the slicer software. The layers solidifies and combines to create the 3D object. The AM technology was initially developed for use in polymeric materials, but has since evolved to introduce other materials such as composites and metals [1]. When the digital 3D model has been imported into the slicer software, many different settings can be changed to achieve the best possible result. Some important param- eters which should be taken into account are the nozzle temperature, the builder plate temperature, volumetric speed limitation, fill percentage, infill structure, sup- port structure, and orientation of the object that will be printed. The temperature settings of the nozzle and the builder plate depend on the material chosen. The nozzle temperature is especially important since it directly affects the 3D printed result. A too high nozzle temperature heats the material too much, which can lead to over extrusion, which in turn can cause surface defects and weakened prints. On the other hand, too low nozzle temperature will not heat the material sufficiently and this can cause the layers to not adhere to each other properly [10]. This and a slower flow rate from the material not being melted enough can lead to print fail- ures. The bed temperature is important to ensure that the first layer adheres to the printing bed, if the first layer does not adhise it will be printing failure [10]. The volymetric speed limitation settings refer to how much plastic the 3D printer will extrude per second. This is a crucial factor that decides how fast the printer can print while keeping the quality of the prints. The speed at which a material can be extruded without affecting the quality of the print varies between different materials, and the speed is often specified by the manufacturer. Normally, when an object is 3D printed, it is not printed as a solid object but as an object with an inner and outer shell that are filled with and infill structure. The percentage of fill refers to how much space between the inner and outer shell walls is filled with this fill structure. An 100% infill would mean that the object is solid and an 0% infill would mean that the object is printed as a shell. A low filling percentage entails that the object is printed quickly but that, on the other hand, gives lower stiffness and durability, while a high filling percentage makes the object stronger but takes more time to print and also requires more material. Infill settings 7 2. Theory can also be changed to different types of infill structure.There is a possibility that the printed material does not have enough time to solidify properly when printing complex geometries or models with overhanging parts. Therefore, it is common for models to be printed with a support structure. A support structure can strengthen overhanging parts during printing and make sure that the material solidifies cor- rectly. A support structure should be printed in such a way that it can be removed easily from the object after the object has been printed. The support structure is generated in the slicer program. It is important to choose the option, support from builder plate only, if all support structures are to be properly removed. This op- tion ensures that the support structure will only be generated on the outside of the object and not inside the infill structure. It is beneficial to avoid support structure if possible, as it takes time to print and remove the material, and it costs money to print the extra material. If needed, the support structure can be printed in a different material from the main object, as long as the printer can handle more than one material at the time. The orientation of the object can be changed to avoid using a support structure. By rotating the object in such a way that the structure supports itself, all supporting structures can be removed. Another thing to consider regarding orientation of the object is that 3D printed parts are stronger along the layers compared to across them[9]. Therefore, it is advantageous to position the object in such a way that it is printed with the layers in the correct direction for the finished object to be as strong as possible. The precision of holes and other details also varies depending on how the object is oriented. Holes, for example, have very good precision when printed laying down compared to when standing, as there is an overhang that can make the holes less precise, which is also something to consider when orienting the object. 2.4 Materials In this Section different filament materials used for 3D printing and their properties will be discussed as well as material properties for the purchased connectors that are used in factories today. 2.4.1 PLA Polylactic acid (PLA) is a biodegradable filament and is one of the most commonly used filaments since it is easy to use and has low printing temperatures. PLA is mainly used for prototypes and decoratives as it is stiff but relatively brittle and has low heat resistance[8]. PLA is also available in combination with carbon fiber, PLA-CF, which provides increased stiffness and strength. Carbon fiber reinforced plastic components are often used for functional prototypes and for applications that requires high mechanical loads[5]. However, with carbon-reinforced polymers, there are some challenges regarding recycling. If the material is recycled, it is difficult to separate carbon fibers from the polymer material[6]. If the fibers are successfully separated, there are still challenges, such as the difficulty of not damaging the fibers during the process, which is necessary for the fibers to retain their properties.The 8 2. Theory material data for PLA and PLA-CF are provided by the manufacturer[8] and can be seen in Table 2.1. Table 2.1: Material data for PLA and PLA-CF from the manufacturer. Material E [MPa] ρ[kg/m3] σy [MPa] PLA 2870 1240 58 PLA-CF 2960 1240 62 2.4.2 PETG Polyethylene Terephthalate Glycol (PETG) is also one of the most commonly used materials used for 3D printing, mainly since the material has a great chemical re- sistance. PETG is a strong, durable and partially flexible plastic that combines the advantages of both PLA and ABS and, due to the properties of the material, it is suitable for technical applications[8]. PETG is also available as an alternative with elements of carbon fiber (PETG-CF), and, as previously mentioned, an addition of carbon fiber provides increased stiffness and strength. The material data provided by the manufacturer[8] can be seen in Table 2.2. Table 2.2: Material data for PETG and PETG-CF from the manufacturer. Material E [MPa] ρ[kg/m3] σy [MPa] PETG 1651 1270 45 PETG-CF 5120 1320 52 2.4.3 TPU Thermoplastic Polyurethane (TPU) is a versatile filament. It has high wear re- sistance, and since it is a ductile filament it is possible to print highly flexible parts. However, it requires a slower printing speed compared to most other filament materials[8]. No material data was presented by the manufacturer for TPU. 2.4.4 PATH-CF PATH-CF is a carbon fiber-reinforced Nylon 12 filament. The material has prop- erties such as being highly wear-resistant, chemically and UV resistant, and having good layer adhesion. The material is usually used for 3D-printing end-use parts. The carbon fibers make the material stiffer and less prone to shrinkage but not stiff enough to reduce the Nylon’s extreme impact resistance. However, the material is more technical to print [8]. The material data provided by the manufacturer[8] can be seen in Table 2.3. Table 2.3: Material data for PATH-CF from the manufacturer. Material E [MPa] ρ[kg/m3] σy [MPa] PATH-CF 1460 1200 58 9 2. Theory 2.4.5 Sustarine Sustarine is the material of which today the connectors purchased are made. The material has high stiffness, high dimensional stability, and is electrically conductive. Material data is provided by the manufacturer [11], see Table 2.4. Table 2.4: Material data for Sustarine from the manufacturer. Material E [MPa] ρ[kg/m3] σy [MPa] Sustarine 3700 1440 45 2.5 Sustainability In this section, 3D printing as a manufacturing method will be compared to the method currently used for the connectors, which is mainly milling, from a sustain- ability perspective. One major difference between AM and traditional machining is material waste. In machining, complex geometries, such as connectors, often require substantial material removal. This results in significant material waste compared to 3D printing, which generates minimal waste, typically limited to initial priming and, if required, support structures. According to Faludi et al. (2015), who compared the environmental impact of 3D printing with a traditional computer numerical control milling machine through a life cycle analysis, the main impact of 3D printing is the use of electricity and for the machining, material waste, and cutting fluid, where the main impacts [3]. Faludi et al. mention that 3D printing had lower ecological impacts per produced part compared to machining. 3D printing also enables local production that reduces transportation-related emissions [4]. 10 3 Methods In this chapter, the different methods used in the project will be presented. This includes 3D printing, FEA, material choice, and physical testing. 3.1 Material investigation To gain a better understanding of the printability and mechanical behavior of the materials, a brief material study was conducted. In order to be able to use the 3D printed connector as a spare part or replacement for an existing connector, the selected material needed to withstand equivalent mechanical loads without yield- ing. When used for prototype testing, the ability to give good surfaces and precise printing is more valuable. Additionally, it had to be a polymer compatible with the available 3D printer. To evaluate this, standardized test specimens were 3D printed to observe surface quality and dimensional accuracy. Tensile tests were also performed on the test specimens to obtain the material properties of the materials. 3.1.1 Poisson’s ratio There were no exact Poisson’s ratio values provided from the manufacturer for any of the materials. Therefore, the values were approximated based on typical ranges for plastic materials found in engineering literature and databases such as MatWeb. Typical Poisson’s ratio values for polymers are 0.33-0.4 [12][13][14] where 0.35 was estimated to be the most common value. An exception was made for TPU, which is a flexible material, and the value 0.45 was estimated. 3.1.2 3D printing test specimens The 3D printer used for this project was Flashforge Guider 3 Ultra and it was used together with the Orca flashforge 1.3.1 slicer program and the Bambu lab X1C with the Bambu studio slicer. The geometry of the test specimens was created in Catia and followed the ISO 527 standard. The drawing and complete test specimen can be seen in Figure 3.2, Appendix .7, for bigger picture. 11 3. Methods Figure 3.1: Test specimens in slicer program. The test specimens were printed on the following materials: PLA, PLA-CF PETG, PETG-CF, TPU, and PATH-CF. For the orientation of the test specimens on the printer bed, see Figure 3.1. The 3D printers settings was changed in the slicer for each material to obtain best possible results. For more details on the settings, see Appendix .1 (a) (b) Figure 3.2: Drawing and complete test specimen in Catia V5. 3.1.3 Tensile testing on test specimens When performing the tensile tests on the test specimens, the plastic tension option was used on the tensile testing machine. Other settings in the machine were: 1. Test speed 10mm/min 2. Prestress 0.2MPa 3. extensiometer max 3% 4. extensiometer measure 2%. 12 3. Methods For a visual representation of the test setup, see Figure 3.3 Figure 3.3: Test setup for 3D printed test specimens. 3.1.4 3D printing connectors The two parts of the connector housing were printed separately and the clams were printed together. The parts and their orientation on the printing bed can be seen in Figures 3.4, 3.5 and 3.6. The support structure was used when printing the second part of the connector housing and the option support from builder plate only was used. (a) (b) Figure 3.4: Part one of the connector housings orientation in slicer. 13 3. Methods (a) (b) Figure 3.5: Second part of the connector housings orientation in slicer. (a) (b) Figure 3.6: Orientation of the clams in slicer. 3.2 Tensile test purchased connector A tensile test was performed to determine the force the connector can withstand before being released from the adapter. When the force is known, it can be used in the FEA to see if the 3D printed connectors would be able to withstand the same force or if they would break. The following settings were used on the tensile testing machine during the test: 1. Type of test: tension-tension 2. sample length 55.0mm 3. sample width 35.0mm 4. sample thickness 35.0mm 5. sample weight 162.0g 6. test speed 30mm/min 7. contacts speed 10mm/min 8. return speed 300mm/min 9. stop load 95% 14 3. Methods 10. minimum travel 1mm 11. contact load 1N 12. max test load 1000N To mimic the load case mentioned in Section 2.1, the connector was attached to the cable gland and connected to the adapter. The adapter was also attached to the machine through its cable gland. The setup can be seen in Figure 3.7. Figure 3.7: Tensile test setup of the purchased connector. 3.3 Finite Element Analysis The goal of the FEA on the purchased connector is to find out where the stress concentrations occur and to see if the connector behaves as expected based on the physical test performed. The goal of FEA on the 3D printed connectors is to see if they would withstand the same force that was required for the purchased connector to release from the adapter without reaching the yield limit. The assembly of the connector provided by the company was opened in the FEA program. To simplify the model, all screws, springs, and pins were removed from the assembly. The remaining components were the two main parts that make up the contact housing, two clamps with attachment shafts, and the cable gland. To mesh parts, the Advance surface mesher was used with parabolic elements and mesh size 8mm with an absolute sag of 0.8mm. The material was then defined and applied to the parts. The material properties used 15 3. Methods when simulating the purchased connector came from a material data sheet provided from the connector manufacturer, see Table 3.1. For the Poisson´s ratio, the value 0.35 and 0.45 was used according to Section 3.1.1. The material properties used when simulating the 3D printed connectors came from data sheets from the manufacturer, and for the materials which had missing data, parameters found from the physical material tensile tests were used. The material data used when simulating 3D printed connectors can be seen in Table 3.1. Table 3.1: Material data used during FEA simulations. Material E [MPa] ρ[kg/m3] σy [MPa] ν [ ] Sustarine 3700 1440 45 0.35 PLA 2870 1240 58 0.35 PLA-CF 2960 1240 62 0.35 PETG 1651 1270 45 0.35 PETG-CF 5120 1320 52 0.35 PATH-CF 1460 1200 58 0.35 TPU 62 1200 9.13 0.45 In order for the analysis tool to understand how the assembly is constrained, connec- tions and boundary conditions were added. To mimic the steel screws that hold the two main parts of the contact housing together, a rigid connection is used, see Figure 3.8. The rigid body connection restricts the movement of the selected surfaces so that the relative positions of the points on the surfaces remain constant throughout the analysis, which means that the surfaces cannot be released from each other. The same type of rigid connection was used between the contact housing and the cable gland, see Figure 3.9. The shafts that attach the clamps to the connector housing were constrained using rigid connections between the outer surface of the shafts and the inner surface of the connector housing holes, see Figure 3.10. In the same way, the clamps were also connected to the shaft with a rigid connection, see Figure 3.11. To allow the clamps to rotate around the shaft, the degree of freedom that rotates around the shaft was released. To ensure that the clamps and the contact housing cannot move through each other, a contact connection was also needed between the underside of the clamp and the outside of the contact housing, see Figure 3.12. 16 3. Methods Figure 3.8: Rigid connection between the first and second parts of the connector housing. Figure 3.9: Rigid connection between cable glamp and the back part of the con- nector housing. Figure 3.10: Rigid connection between the shaft and connector housing. Figure 3.11: Rigid connection between the shaft and clams. 17 3. Methods Figure 3.12: Contact connection between the connector housing and clams. Next, the boundary conditions were added. To resemble the selected load case, the sub-assembly was clamped at the end of the cable gland. The boundary condition can be seen in Figure 3.13. The second boundary condition was a distributed force that was added to the interior of the clams. The magnitude of the force was the maximum force that was found during the physical tensile test performed on the connector, and the force had the same direction as the local x-axis of the clams, see Figure 3.14. Figure 3.13: Clamped boundary condition. 18 3. Methods Figure 3.14: Distributed force boundary condition. To study more clearly where the stress concentrations occurred, a local mesh was applied to the clamps. Figure 3.15 shows where the local mesh was implemented. To decide on the appropriate size of the local mesh, a mesh sensitivity study was performed. A mesh sensitivity analysis makes it possible to find a balance between avoiding unnecessary computational cost and obtaining a converged solution. The local mesh result was iterated with different mesh sizes to find the optimal mesh. As a metric for comparison between the mesh sizes, the maximum von Mises stress is chosen. 19 3. Methods Figure 3.15: Selected surfaces where a local mesh was added are highlighted or- ange. Since the connector is printed with 100% infill, the connector becomes solid and can be simulated in the same way as the purchased connector. Two types of FEA simulations were performed for the 3D printed connectors, one in which the entire connector except for the shafts was made of plastic material, and the other type of calculations where only the connector housing was made of 3D printed material and the clamps were made of steel similar to the purchased one. 20 4 Results 4.1 Material investigation Three test specimens were printed and tested in each material. The material data obtained, see Table 4.1, from the tensile test are a mean value of all tests that were valid, which means that the test was performed correctly and that the sample did not slip during the test. All PLA test specimens cracked before the yield stress was found and all test specimens cracked before Poisson’s ratio was found. Table 4.1: Material data from tensile testing 3D printed test specimens. Material E [MPa] σy [MPa] ν [ ] Sustarine 5101 32 - PLA 2383 - - PLA-CF 5201 47 - PETG 1478 39 - PETG-CF 5317 22 - PATH-CF 2993 34 - TPU 62 9.13 - A connector component was printed in each material, with the exception of PATH- CF. This material was excluded because of the challenges in achieving acceptable print settings and the poor surface quality that it produced, which made it un- suitable for printing connectors. After the different materials were printed, several visual observations were made regarding the printability and surface quality. PLA and PETG were the easiest to print and showed consistent results throughout the process. Both materials produced clean surfaces where the layers bonded well and had accurate hole geometries without the need for significant parameter adjustments in the slicer. PLA-CF and PETG-CF resulted in finer, more matte surface finishes because of the carbon fiber, which contributed to a more technical appearance. However, these materials showed a poorer result around small holes. ,see Figure 4.1. TPU required a print speed roughly half that of the other materials. Issues such as deformation in corners, holes, and insufficient layer bonding were observed; see Figure 4.2. PATH-CF had a noticeably rougher surface finish compared to the other materials; see Figure 4.3 21 4. Results (a) PLA. (b) PETG. (c) PLA-CF. (d) PETG-CF. Figure 4.1: Surface printing results for PLA, PETG, PLA-CF and PETG-CF. 22 4. Results (a) (b) Figure 4.2: Observed issues from printed TPU, (a) deformation in corners and holes, and (b) insufficient layer bonding. Figure 4.3: Surface of a 3D printed test specimen in PATH-CF. 4.2 Tensile test purchased connector In Figure 4.4, a graph visualizes the load-deformation curve for the connector. The maximum force the connector could withstand before it detached from the adapter was 213.9 N, see Appendix .3 for raw data. 23 4. Results Figure 4.4: Force versus pull-out displacement required for the connector to detach from the adapter. 4.3 Finite Element analysis results This part of the report presents the findings of the FEA simulations. This includes mesh sensitivity analysis, FEA on purchased connectors, and 3D printed connectors. 4.3.1 Mesh sensitivity This section shows the results of the local mesh sensitivity analysis; the local mesh size with associated von Mises stress is shown in Table 4.2. At a mesh size of 0.25 mm, a clear trend could be observed where the von Mises stress started to increase rapidly compared to previous mesh sizes. This indicates that the model is approaching a singular behavior in the area where the force is applied. When the mesh was refined to 0.0625 mm, an error occurred in the simulation, confirming that a singularity had occurred. Consequently, a 0.5 mm local mesh size was chosen as it offers a balance between numerical stability and solution accuracy, lying just before the point where the results begin to diverge due to over-refinement. Figure 4.5 shows a visual representation of the stress concentration for some of the different iterations. 24 4. Results Table 4.2: Mesh sensitivity analysis showing von Mises stress for different local mesh sizes. Local mesh size [mm] von Mises stress [Pa] 8 2.16·107 4 2.22·107 2 2.10·107 1 2.43·107 0.5 2.59·107 0.25 3.55·107 0.125 4.80·107 0.0625 - (a) Local mesh size 2mm. (b) Local mesh size 1mm. (c) Local mesh size 0.5mm. (d) Local mesh size 0.25mm. Figure 4.5: Comparison between a local mesh of 2,1,0.5,0.25 mm respectivaly. 4.3.2 FEA results purchased connector When applying a distributed force with a magitude of 213.9N the maximum von Mises stress for the purchased connector was 25,9 MPa. The simulation results can be seen in Figures 4.6 and 4.7. 25 4. Results Figure 4.6: Result of FEA simulation of the purchased connectorfrom the side. Figure 4.7: Result of FEA simulation of the purchased connector from above. 4.3.3 Finite Element Analysis results 3D printed connectors The von Mises stress results for the 3D printed connectors when loaded with a force of 213.9 N has been gathered in a table, see Table 4.3. From the table it can be seen that the simulations, in which only the housing was simulated with the 3D printed material and the metal clams, gave the same results. For a visual representation of the simulation results,see Figures 4.8 and 4.9, for larger pictures, see Appendix .4. 26 4. Results Table 4.3: von Mises stress results from simulating the different 3D printed mate- rials. Material von Mises stress [Pa] PLA (all parts) 2.67·107 PLA (only housing) 2.59·107 PLA-CF(all parts) 2.69·107 PLA-CF (only housing) 2.59·107 PETG(all parts) 2.61·107 PETG (only housing) 2.59·107 PETG-CF(all parts) 2.72·107 PETG-CF (only housing) 2.59·107 TPU(all parts) 2.54·107 TPU (only housing) 2.59·107 PATH-CF (all parts) 2.69·107 PATH-CF (only housing) 2.59·107 27 4. Results (a)PLA, von Mises stress: 2.67 ·107Pa (b) PLA-CF, von Mises stress: 2.69 · 107Pa (c) PETG, von Mises stress: 2.61 · 107Pa (d) PETG-CF, von Mises stress: 2.72· 107Pa (e) TPU, von Mises stress: 2.54·107Pa (f) PATH-CF, von Mises stress: 2.69 · 107Pa Figure 4.8: FEA simulations for the 3D printed materials. 28 4. Results (a)PLA, von Mises stress: 2.59 ·107Pa (b) PLA-CF, von Mises stress: 2.59 · 107Pa (c) PETG, von Mises stress: 2.59 · 107Pa (d) PETG-CF, von Mises stress: 2.59· 107Pa (e) TPU, von Mises stress: 2.59·107Pa (f) PATH-CF, von Mises stress: 2.59 · 107Pa Figure 4.9: FEA simulations for the 3D printed materials with metal clams. 29 4. Results 30 5 Discussion and Conclusion In this section, results and suggestions on follow-up studies will be discussed. 5.1 Material data The results of the tensile test on the test specimens presented in Table 4.1 differ from the material data provided by the manufacturer, Table 2.1, 2.2, 2.3 and 2.4. In particular, three of the materials, namely, Sustarine, PLA-CF, and PATH-CF, had extra large differences. A possible source of error for this is that different loading speeds may have been used during the testing. Something else that may have also affected this is whether the test specimen is mounted completely centered and straight in the machine during testing and whether the test specimen slipped during the test. For PLA-CF and PATH-CF, which were 3D printed, other printer settings may also have been used during the tests, and only three tests were conducted per material. An advantage of using the results of the tensile tests carried out in this project is that it can be ensured that the same printer settings were used during the tests as when the connectors were printed. However, the sources of error for mounting test specimens wrong and test machine settings are considered to be greater than the printer settings, and it was chosen to use the manufacturers material data for the simulations for all materials where possible. 5.2 3D printing and materials In Section 4.1 some results regarding printability and surface quality were obtained. After the test specimens were printed, connectors were also printed in all materials except PATH-CF. PATH-CF had challenges in achieving acceptable print settings and resulted in rough surface quality; it was removed from further investigation. The next material that could be excluded was TPU as it needed much longer printing time, insufficient layer bonding, and deformation in corners as a result of challenging printer settings. That leaves PLA, PLA-CF, PETG and PETG-CF as options. All four materials were easy to print and had consistent results. The carbon fiber-infused materials resulted in a better surface finish but led to a poorer result around small holes. However, this is not considered a problem for the selected connector-design as the holes that were affected could be drilled instead. As a follow-up study, it is of interest to investigate other materials and other printer settings, such as comparing different infill structures and infill percentages. Something that could also be stud- ied further is to perform physical tensile tests on the 3D printed contacts, similar to 31 5. Discussion and Conclusion what was done for the purchased contact, to see if they behave as expected. This could not be done in this project, as there was no suitable way to attach the 3D printed contacts to the test machine. It is also worth noting that production has had problems with materials contain- ing carbon fiber being conductive. This has led to contacts becoming hot during use, which should be avoided. The resistance was therefore measured with a multi- meter on the 3D printed test specimens, but no conductive properties were found. Therefore, the carbon fiber-containing materials investigated during this study are considered suitable. 5.3 Finite Element Analysis The results of the FEA simulation on the purchased connector are considered good, since the simulation confirmed the behavior that was shown during the physical test, and therefore the simulation setup was considered appropriate to use when studying the 3D printed materials. For all simulations, the stress concentrations emerged in the inner corner of the clamps, and the von Mises stress only reached its yield stress value for connector with the material TPU. This indicates that all other materials could be appropriate for printing the connector. From the results it can also be seen that all simulations in which metal clams were used gave the same results, see Table 4.3. This is considered reasonable since the stress concentration is on the clams. If the connector was to be used as a spare part, an option could be to purchase metal clamps to assemble and only print the connector housing. To be able to know if a 3D printed connector could have completely replaced a purchased connector, more studies would have needed to be done, such as fatigue analysis, material wear, and a field study where the connector is tested over time in the factory. Other follow-up studies could be to investigate how the connector would react in different load cases, for example, a load case with side loads. The design of the connector is also something to investigate. A different placement of the shaft between the connector housing and the clam would lead to different forces, and the connector may behave differently and may be able to withstand more force before attaching from the adapter. 5.4 Sustainability As mentioned in Section 2.5 3D printing as a manufacturing method can offer a more sustainable alternative to traditional machining, particularly due to its poten- tial to reduce material waste. Furthermore, biodegradable materials such as PLA are available for use in 3D printing, which contributes to its environmental benefits. However, as mentioned in Section 2.4.1, it is important to recognize that certain advanced materials, such as carbon fiber-reinforced polymers, have significant chal- lenges in terms of recyclability. 32 5. Discussion and Conclusion 5.5 Fulfillment of aim and goals The thesis was divided into different problem areas; see Section 1.4 that should be met to carry out the work. This Section will discuss the fulfillment of the problem areas. The first goal was to examine which material was suitable for 3D printed connectors through tensile testing and to evaluate the ease of printing and printing results. This goal is considered to be achieved; see Section 5.2. The second goal was to investigate what parts of the connector are suitable for 3D printing. As discussed in Section 5.3, the results suggest that it would be feasible to 3D print the entire connector, or an option could be to only print the connector housing and assemble the connector using purchased metal clams. Based on the discussion, the goal is considered to have been met. The third goal, which type of load case should be investigated, is considered to be fulfilled; see Section 2.1. The fourth goal was to investigate 3D printed connectors during the selected load case by performing finite element analy- sis and physical tests. Tensile tests were performed on the purchased connector and FEA simulations were done on the connector in the 3D printed materials. However, no physical tests could be performed on the 3D printed connectors, see Section 5.2, therefore this goal is considered to be partially achieved. The fifth goal was to examine whether the FEA matches the physical testing of the 3D printed connectors. As mentioned in Section 5.2, there was no suitable way to attach the 3D printed connectors to the test machine, so no tests were performed. Therefore, this goal is considered not to have been achieved. The sixth goal was to compare the stresses of the purchased and 3D printed connectors that occurred during the selected loadcase. From the FEA results, the stresses were compared and, therefore, this goal is considered fulfilled. The last goal was to investigate how the chosen material and 3D printing as a manufacturing method affect the environment compared to the machined connector, and this was discussed in Section 5.4, the goal is considered fulfilled. 5.6 Conclusion From this study, it can be seen that there are four materials that could be suitable for 3D printing connectors, PLA, PLA-CF, PETG, and PETG-CF for use as spare part. However, further studies are needed to determine whether 3D printed contacts can replace existing ones over a longer period of time. 33 5. Discussion and Conclusion 34 Bibliography [1] I. Gibson, D Rosen, B Stucker and M. Khorasani (2021) Additive Manufactur- ing Technologies. DOI: https://doi.org/10.1007/978-3-030-56127-7 [2] Ottosen, N. S. & Petersson, H. (1992) Introduction to the finite element method. Prentice Hall. [3] J. Faludi, C. Bayley, S. Bhogal, and M. 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Kuentz, A. Salem, M. Singh, M.C. Halbig, J.A. Salem "Additive Man- ufacturing and Characterization of Polylactic Acid (PLA) Composites Con- taining Metal Reinforcements," NASA Technical Reports Server, Jan. 2016. [Online]. Available: https://ntrs.nasa.gov/api/citations/20160010284/ downloads/20160010284.pdf [Accessed: Jun 4 2025]. [14] “Poisson’s Ratio of Common Materials,” Matmake. [Online]. Available: https: //matmake.com/properties/poissons-ratio-of-common-materials.html [Accessed: Jun 4 2025]. 36 https://ntrs.nasa.gov/api/citations/20160010284/downloads/20160010284.pdf https://ntrs.nasa.gov/api/citations/20160010284/downloads/20160010284.pdf https://matmake.com/properties/poissons-ratio-of-common-materials.html https://matmake.com/properties/poissons-ratio-of-common-materials.html A Appendix 1 .1 3D-print settings .1.1 PLA Figure .1: 3D print settings for PLA. I A. Appendix 1 .1.2 PLA-CF Figure .2: 3D print settings for PLA-CF. II A. Appendix 1 .1.3 PETG Figure .3: 3D print settings for PETG. III A. Appendix 1 .1.4 PETG-CF Figure .4: 3D print settings for PETG-CF. IV A. Appendix 1 .1.5 TPU Figure .5: 3D print settings for TPU. V A. Appendix 1 .1.6 PATH-CF Figure .6: 3D print settings for PATH-CF. VI A. Appendix 1 .2 CAD drawing Figure .7: CAD drawing of test specimen. .3 Tensile test purchased connector Listing 1: Raw data from measurements, deformation in the left column, force in the right. mm N 0.000127314808196388 1.00527560710907 0.00516189122572541 1.74207961559296 0.013857813552022 2.86983823776245 0.0239244252443314 4.37571859359741 0.0340384989976883 6.08730459213257 0.0440861210227013 7.8343391418457 VII A. Appendix 1 0.0540000163018703 9.66281795501709 0.0637675821781158 11.7328319549561 0.0738155394792557 13.4755458831787 0.0838523879647255 15.3594217300415 0.0939763486385345 16.9454746246338 0.104031287133694 18.599630355835 0.114290527999401 20.0844192504883 0.124048359692097 21.469596862793 0.134244680404663 22.9451103210449 0.145074665546417 24.4574699401855 0.155279248952866 25.8280353546143 0.165176823735237 27.0554065704346 0.175136238336563 28.3057746887207 0.185350373387337 29.5548725128174 0.195246294140816 30.803337097168 0.205323830246925 32.1704711914063 0.215468212962151 33.4970741271973 0.225355803966522 34.8511199951172 0.235517844557762 35.9534683227539 0.245757028460503 36.8846702575684 0.255669802427292 37.9189147949219 0.265764772891998 39.0648422241211 0.276056379079819 40.138599395752 0.28622642159462 41.1393013000488 0.296129137277603 42.3013648986816 0.306234121322632 43.3198547363281 0.316464394330978 44.363883972168 0.326193779706955 45.302074432373 0.330562204122543 45.6059951782227 0.347439616918564 46.3105239868164 0.35722890496254 47.2961082458496 0.367642164230347 48.4416542053223 0.377873033285141 49.4784393310547 0.387659400701523 50.5011215209961 0.398031800985336 51.3573608398438 0.407638430595398 52.2374839782715 0.417856097221375 53.4417304992676 0.427779078483582 54.3465042114258 0.43808525800705 55.2350158691406 0.446433812379837 55.9239158630371 0.463865607976913 56.8635063171387 0.473729819059372 57.7058944702148 0.483647018671036 58.6842308044434 0.494129806756973 59.755069732666 0.504052460193634 60.6640357971191 0.514431297779083 61.4384498596191 0.524172306060791 62.2288703918457 0.534286439418793 63.1308479309082 0.544478476047516 63.8527870178223 0.554477334022522 64.6021728515625 0.56441742181778 65.3127975463867 0.574227333068848 66.1771697998047 0.584184169769287 66.7447357177734 0.594064176082611 67.5113983154297 0.604516506195068 68.2875900268555 0.61447262763977 68.8654403686523 VIII A. Appendix 1 0.624817073345184 69.3463516235352 0.634580314159393 69.9538116455078 0.644674181938171 70.3734817504883 0.655023515224457 70.7803192138672 0.665104150772095 71.401123046875 0.675306856632233 72.1009521484375 0.685386121273041 72.7419509887695 0.69579005241394 73.2867736816406 0.705550253391266 73.9392166137695 0.715693473815918 74.576530456543 0.725838959217071 75.1785278320312 0.736105799674988 75.8711166381836 0.746120691299438 76.5240631103516 0.756331324577332 77.1030578613281 0.766468942165375 77.8248748779297 0.776429235935211 78.3395843505859 0.786572992801666 78.9688949584961 0.797166049480438 79.54052734375 0.807328283786774 79.888916015625 0.817276895046234 80.5809936523437 0.827423751354217 81.1625366210937 0.837503790855408 81.792610168457 0.847462773323059 82.3265075683594 0.857279598712921 83.0863037109375 0.87474662065506 83.6750869750977 0.884830236434937 84.2501525878906 0.895169675350189 84.8067855834961 0.90506899356842 85.2808380126953 0.91483861207962 85.7912216186523 0.925167798995972 86.5041427612305 0.935319721698761 87.0086822509766 0.945406794548035 87.5312728881836 0.955765962600708 87.788818359375 0.965659916400909 88.3449478149414 0.975628197193146 88.7379302978516 0.985903918743134 89.2964782714844 0.996118605136871 89.8147430419922 1.00600945949554 90.4166107177734 1.01630175113678 90.7234497070312 1.02607786655426 91.135498046875 1.03636884689331 91.462287902832 1.04670882225037 92.0104141235352 1.05654525756836 92.4727783203125 1.0665088891983 92.9369125366211 1.07729935646057 93.4109649658203 1.08757138252258 94.0247802734375 1.0972204208374 94.4341583251953 1.10730981826782 94.9214172363281 1.11758947372437 95.4198608398438 1.1275440454483 96.0216064453125 1.13781881332397 96.5933609008789 1.14784944057465 97.0068054199219 1.15813195705414 97.461799621582 1.16842615604401 97.7389068603516 1.17839431762695 98.1352005004883 1.18867242336273 98.6565170288086 IX A. Appendix 1 1.19851386547089 99.0426406860352 1.20879936218262 99.452018737793 1.21894788742065 100.009544372559 1.22884953022003 100.447509765625 1.23913466930389 100.861968994141 1.24910032749176 101.296760559082 1.25943922996521 101.861907958984 1.26927089691162 102.396438598633 1.27935743331909 102.92626953125 1.28964340686798 103.329040527344 1.29972624778748 103.916046142578 1.30987048149109 104.538116455078 1.31964039802551 105.043418884277 1.32967102527618 105.456993103027 1.33975613117218 106.009819030762 1.35010814666748 106.375358581543 1.36006164550781 106.992858886719 1.37045860290527 107.642753601074 1.38092648983002 108.183258056641 1.39120304584503 108.729598999023 1.40134418010712 109.397033691406 1.41118037700653 109.863075256348 1.42127132415771 110.32772064209 1.43162560462952 110.65845489502 1.44158530235291 111.183074951172 1.45148956775665 111.58203125 1.46132719516754 112.026092529297 1.47173058986664 112.577651977539 1.48149704933166 113.136825561523 1.4914653301239 113.529052734375 1.50181818008423 113.884048461914 1.51159083843231 114.347938537598 1.52194249629974 114.718940734863 1.53172123432159 115.090461730957 1.54193949699402 115.554214477539 1.55196261405945 116.082649230957 1.56243312358856 116.582359313965 1.57238805294037 117.178771972656 1.58216464519501 117.582557678223 1.5925794839859 117.961822509766 1.60241627693176 118.419097900391 1.61231243610382 118.941047668457 1.62222051620483 119.282196044922 1.63211929798126 119.763748168945 1.64259970188141 120.113151550293 1.6524441242218 120.453918457031 1.6627368927002 120.754409790039 1.6727077960968 121.107116699219 1.68293750286102 121.397956848145 1.69290590286255 121.790306091309 1.70287299156189 122.201461791992 1.71309375762939 122.62825012207 1.72300255298614 122.958213806152 1.73335516452789 123.314353942871 1.75318384170532 123.806190490723 1.76315891742706 124.097915649414 X A. Appendix 1 1.77332031726837 124.458122253418 1.7834963798523 124.59635925293 1.79365873336792 124.943481445313 1.80407059192657 125.366577148438 1.82390403747559 125.786758422852 1.8340562582016 126.28736114502 1.8539502620697 126.753410339355 1.87135410308838 127.335327148438 1.88852143287659 127.641159057617 1.89836931228638 127.930465698242 1.90871620178223 128.373001098633 1.91868948936462 128.691787719727 1.92890381813049 129.215393066406 1.93887722492218 129.530883789062 1.94891023635864 129.908615112305 1.95919692516327 130.300079345703 1.96929180622101 130.703231811523 1.97945070266724 131.102188110352 1.98960769176483 131.530380249023 1.99989295005798 131.943176269531 2.00985646247864 132.409484863281 2.01982378959656 132.818725585938 2.02973103523254 133.170928955078 2.03969979286194 133.557189941406 2.04985976219177 133.939498901367 2.06015658378601 134.178237915039 2.06993341445923 134.577590942383 2.08042001724243 134.835388183594 2.09020209312439 135.155181884766 2.10036516189575 135.489974975586 2.12064409255981 135.911422729492 2.13061499595642 136.266174316406 2.14091110229492 136.515335083008 2.15074920654297 136.951141357422 2.16102910041809 137.447799682617 2.17087841033936 137.714492797852 2.18084955215454 138.063522338867 2.19074821472168 138.54621887207 2.20103645324707 138.917465209961 2.21082758903503 139.099792480469 2.22085928916931 139.495956420898 2.23083090782166 139.839019775391 2.2410581111908 140.168991088867 2.25141668319702 140.434158325195 2.26126050949097 140.783309936523 2.27155518531799 141.054824829102 2.28134393692017 141.274505615234 2.29176497459412 141.559371948242 2.30173563957214 141.917663574219 2.31158256530762 142.219436645508 2.32193613052368 142.564392089844 2.33222031593323 142.991806030273 2.34212946891785 143.317459106445 2.3519766330719 143.617568969727 2.36265277862549 143.895950317383 2.37294054031372 144.269622802734 XI A. Appendix 1 2.38271474838257 144.710632324219 2.39268898963928 145.015197753906 2.4031081199646 145.327621459961 2.41294765472412 145.742218017578 2.4232337474823 146.143203735352 2.43320250511169 146.5283203125 2.44336748123169 146.836807250977 2.45353007316589 147.178970336914 2.46344184875488 147.463073730469 2.47391438484192 147.934204101562 2.49407267570496 148.251724243164 2.50385594367981 148.557159423828 2.51420545578003 148.961074829102 2.52430009841919 149.367782592773 2.53413891792297 149.795333862305 2.54417109489441 150.184005737305 2.55414724349976 150.457565307617 2.56431460380554 150.72819519043 2.5746111869812 150.97087097168 2.59488844871521 151.417984008789 2.60486173629761 151.73486328125 2.61502981185913 151.994064331055 2.62519264221191 152.335083007813 2.63555288314819 152.576232910156 2.6454586982727 152.949142456055 2.65555357933044 153.354721069336 2.66578483581543 153.621658325195 2.67569947242737 153.864212036133 2.68573832511902 154.150726318359 2.69583868980408 154.472808837891 2.71605563163757 154.870635986328 2.72622632980347 155.088531494141 2.74727010726929 155.496139526367 2.7571804523468 155.802093505859 2.77732944488525 156.264694213867 2.78762722015381 156.486038208008 2.79747366905212 156.799224853516 2.80770421028137 157.076721191406 2.81787180900574 157.343032836914 2.82822585105896 157.677825927734 2.83813381195068 158.022277832031 2.84835886955261 158.382995605469 2.85826539993286 158.746002197266 2.86811447143555 159.015747070313 2.87840533256531 159.346466064453 2.8986873626709 159.718109130859 2.90853404998779 160.024444580078 2.92881107330322 160.477401733398 2.93884444236755 160.847015380859 2.94882416725159 161.069488525391 2.96898317337036 161.376205444336 2.97927689552307 161.664367675781 2.99930167198181 162.078323364258 3.00966191291809 162.316818237305 3.01970267295837 162.577285766602 3.03966999053955 162.897720336914 XII A. Appendix 1 3.06001114845276 163.34228515625 3.07024168968201 163.620162963867 3.08028626441956 163.820907592773 3.0904529094696 164.103866577148 3.10042929649353 164.374252319336 3.11103940010071 164.685028076172 3.12152743339539 164.922622680664 3.14130353927612 165.244583129883 3.15166831016541 165.417892456055 3.17157435417175 165.702377319336 3.19185137748718 166.15087890625 3.21181988716126 166.453414916992 3.23190784454346 166.876129150391 3.2422034740448 167.132781982422 3.26236462593079 167.408874511719 3.28258895874023 167.694381713867 3.29295444488525 167.854080200195 3.31298232078552 168.220397949219 3.33346009254456 168.524444580078 3.3533775806427 168.635101318359 3.37353515625 168.967361450195 3.38351011276245 169.25959777832 3.40366148948669 169.683578491211 3.42426609992981 169.992202758789 3.44418430328369 170.091186523438 3.46434903144836 170.314544677734 3.48450398445129 170.685302734375 3.49480605125427 170.843872070313 3.51509642601013 171.090362548828 3.5351984500885 171.300628662109 3.55637049674988 171.692352294922 3.57665753364563 171.992462158203 3.58670282363892 172.181655883789 3.60718679428101 172.388748168945 3.61717057228088 172.547073364258 3.63739609718323 172.816177368164 3.65756177902222 173.022125244141 3.66786217689514 173.205093383789 3.68801641464233 173.586517333984 3.69569897651672 173.892730712891 3.71325254440308 174.130706787109 3.72348785400391 174.337677001953 3.7334578037262 174.705123901367 3.75393557548523 175.008285522461 3.77372026443481 175.200012207031 3.78422379493713 175.201156616211 3.80421161651611 175.208282470703 3.8243899345398 175.224792480469 3.83468842506409 175.437606811523 3.84446716308594 175.809631347656 3.86500477790833 176.171249389648 3.8849093914032 176.474533081055 3.90520811080933 176.597900390625 3.92538619041443 176.618225097656 3.935387134552 176.515182495117 3.95530390739441 176.636901855469 XIII A. Appendix 1 3.97568082809448 176.538055419922 3.98592162132263 176.65901184082 4.00634288787842 176.856460571289 4.01613330841064 177.050979614258 4.03673696517944 177.37370300293 4.04805612564087 177.549179077148 4.06802749633789 177.812561035156 4.08838415145874 178.014709472656 4.0983624458313 178.256256103516 4.11846590042114 178.442764282227 4.12876272201538 178.684814453125 4.14899110794067 178.908432006836 4.15927934646606 179.274108886719 4.16925811767578 179.510299682617 4.1891598701477 179.856918334961 4.2094554901123 180.028442382813 4.22929954528809 180.282928466797 4.24952602386475 180.538452148438 4.26964092254639 180.552673339844 4.28987121582031 180.739959716797 4.31035327911377 180.983657836914 4.33024597167969 181.465194702148 4.34022092819214 181.756423950195 4.35051965713501 181.969360351562 4.37056398391724 182.085876464844 4.38116550445557 181.564559936523 4.39106845855713 181.014022827148 4.40109968185425 180.45280456543 4.4111123085022 180.179504394531 4.42102336883545 180.474533081055 4.43096494674683 181.269668579102 4.44097280502319 182.02653503418 4.45092058181763 182.732345581055 4.46087551116943 183.333572387695 4.47129392623901 183.654907226562 4.48139619827271 183.946365356445 4.49958562850952 184.19743347168 4.51178884506226 184.48649597168 4.52157783508301 184.700454711914 4.5316801071167 184.998275756836 4.54191637039185 185.185180664062 4.56310272216797 185.364196777344 4.58314275741577 185.544372558594 4.60375213623047 185.783233642578 4.62390518188477 186.18244934082 4.64444446563721 186.519271850586 4.66435718536377 186.700454711914 4.6746563911438 186.904006958008 4.69475984573364 187.084548950195 4.70492172241211 187.440689086914 4.71527194976807 187.831390380859 4.72549724578857 188.194900512695 4.7353367805481 188.604415893555 4.74524116516113 189.006286621094 4.75547456741333 189.235763549805 4.7654504776001 189.5146484375 XIV A. Appendix 1 4.78572988510132 189.930374145508 4.80587768554687 190.408996582031 4.82648229598999 190.717880249023 4.83627271652222 190.915710449219 4.85668897628784 191.185317993164 4.87742185592651 191.480224609375 4.89765214920044 191.670043945313 4.90801525115967 191.870666503906 4.92817115783691 192.224014282227 4.94808435440063 192.403030395508 4.96794271469116 192.44255065918 4.98856830596924 192.43391418457 5.00854587554932 192.596420288086 5.01884984970093 192.729705810547 5.03871297836304 192.697296142578 5.05902147293091 192.670623779297 5.07791948318481 192.799194335938 5.09452390670776 192.948364257813 5.1046929359436 193.192947387695 5.1149263381958 193.428009033203 5.13527202606201 193.804229736328 5.14556503295898 194.097213745117 5.16540384292603 194.436965942383 5.17569303512573 194.794128417969 5.18560266494751 195.109100341797 5.19583463668823 195.363220214844 5.20574808120728 195.628387451172 5.2260274887085 196.036102294922 5.23587322235107 196.362777709961 5.24610662460327 196.592239379883 5.25646352767944 196.88395690918 5.26624917984009 197.151153564453 5.28672456741333 197.491287231445 5.3070011138916 197.951232910156 5.31722497940063 198.325042724609 5.3375039100647 198.75373840332 5.34773063659668 199.08268737793 5.36890602111816 199.424850463867 5.37888431549072 199.671966552734 5.39923477172852 199.974243164062 5.40940284729004 200.233306884766 5.41938066482544 200.476119995117 5.43959379196167 200.934280395508 5.44982576370239 201.192459106445 5.46011638641357 201.519760131836 5.48003101348877 201.673248291016 5.50012874603271 201.95036315918 5.51029968261719 202.164321899414 5.52027082443237 202.516784667969 5.54080533981323 202.922988891602 5.55084753036499 203.15803527832 5.57081460952759 203.481658935547 5.58065938949585 203.817596435547 5.60081958770752 204.112991333008 5.61111783981323 204.323791503906 5.6212797164917 204.682723999023 XV A. Appendix 1 5.63138198852539 204.975463867187 5.64173603057861 205.30517578125 5.65197324752808 205.48762512207 5.67193269729614 205.925216674805 5.69210004806519 206.106903076172 5.71201658248901 206.229263305664 5.72200727462769 206.284271240234 5.7334451675415 206.594543457031 5.75372982025146 206.931884765625 5.77414512634277 207.213439941406 5.79412317276001 207.368713378906 5.80410671234131 207.535034179687 5.82408142089844 207.745559692383 5.84449052810669 208.122787475586 5.86484479904175 208.364334106445 5.87482404708862 208.593536376953 5.8949933052063 208.743087768555 5.90522861480713 208.948669433594 5.92507553100586 209.164276123047 5.94535493850708 209.578735351562 5.96597003936768 209.733627319336 5.98632383346558 209.984817504883 6.00604963302612 210.103225708008 6.01648283004761 210.200424194336 6.03652477264404 210.358367919922 6.05675649642944 210.526580810547 6.07704257965088 210.842193603516 6.09706783294678 211.247131347656 6.10762214660644 211.443054199219 6.12777900695801 211.78889465332 6.13801431655884 211.991424560547 6.15818119049072 212.181625366211 6.16855049133301 212.28581237793 6.18853902816772 212.28581237793 6.19885349273682 212.255706787109 6.21865177154541 212.238677978516 6.23894357681274 212.467254638672 6.25909376144409 212.914108276367 6.27932929992676 213.023895263672 6.28950929641724 213.107376098633 6.30980539321899 213.264022827148 6.31966304779053 213.408111572266 6.34014940261841 213.576461791992 6.36011552810669 213.914947509766 6.3706316947937 213.722320556641 6.37522411346436 201.991012573242 XVI A. Appendix 1 .4 Figures simulated connector Figure .8: Connector in PLA Figure .9: Connector in PLA-CF XVII A. Appendix 1 Figure .10: Connector in PETG Figure .11: Connector in PETG-CF XVIII A. Appendix 1 Figure .12: Connector in TPU Figure .13: Connector in PATH-CF XIX A. Appendix 1 Figure .14: Connector in PLA except the clams. Figure .15: Connector in PLA-CF except the clams. XX A. Appendix 1 Figure .16: Connector in PETG except the clams. Figure .17: Connector in PETG-CF except the clams. XXI A. Appendix 1 Figure .18: Connector in TPU except the clams. Figure .19: Connector in PATH-CF except the clams. XXII DEPARTMENT OF SOME SUBJECT OR TECHNOLOGY CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden www.chalmers.se www.chalmers.se List of Acronyms List of Figures List of Tables Introduction Background Aim Limitations Problem formulation Use of artificial intelligence Theory Selected connector and load case Finite Element Analysis 3D Printing Materials PLA PETG TPU PATH-CF Sustarine Sustainability Methods Material investigation Poisson's ratio 3D printing test specimens Tensile testing on test specimens 3D printing connectors Tensile test purchased connector Finite Element Analysis Results Material investigation Tensile test purchased connector Finite Element analysis results Mesh sensitivity FEA results purchased connector Finite Element Analysis results 3D printed connectors Discussion and Conclusion Material data 3D printing and materials Finite Element Analysis Sustainability Fulfillment of aim and goals Conclusion Bibliography Appendix 1 3D-print settings PLA PLA-CF PETG PETG-CF TPU PATH-CF CAD drawing Tensile test purchased connector Figures simulated connector