Several active methods, which requires external control systems and moving parts, have been developed to control the fiber orientation during 3D printing. Active mechanisms like rotating nozzle, impeller, and magnetic field have been integrated to realize complex internal fiber structures. In this study, instead of using active methods, I investigate a passive method for controlling the fiber orientation without any moving parts or additional mechatronics added in the printing process. Composites of polydimethylsiloxane (PDMS) and glass fibers (GF) are 3D printed. Channels, such as helicoid, are designed and integrated to guide the ink flow and passively result in different pre-alignment of fibers before the ink flow into narrow nozzle space. While passing through the designed channels, the fibers orient due to the shear between channel walls and the ink. The effect of helicoids with different pitch sizes are investigated via mechanical experiments, microstructural analysis, and numerical simulations. The results show that both surface to volume ratio and helix angle of the channel affect pre-alignment of fiber orientation at the entry of nozzle. The internal fiber structures lead to enhanced and tunable mechanical properties of printed composites. Pitch size 7-9 mm (helix angle of 7.92- 10.15o) is found to be optimal for the 3D printed PDMS-GF composites. Stiffness and strength can be tuned up to 77.6% and 47.8%, respectively, compared with the case without helicoid channel. Channels of parallel holes, parallel holes with taper end and gradually changing pitch helicoids are experimentally tested, showing further enhancement in mechanical properties.

2025 / The skin, with its high density of specialized neurons, provides a rich platform for discrete communication through haptic feedback technologies. However, current manufacturing techniques for haptic devices are labor-intensive and require significant technical expertise, limiting accessibility and broader adoption. Existing processes involve specialized PCB software for circuit design, followed by multi-step integration into a soft polymer matrix, resulting in prolonged lead times and limited design flexibility. Furthermore, these devices typically rely on external computing units for controlling tactile patterns and intensity, often decoupling the two. This work proposes fabrication strategies ranging from benchtop 3D printing to hybrid techniques that integrate innovative materials with intuitive interfaces, enabling customizable and accessible haptic devices. We aim to create wearable haptic devices with direct, human-in-the-loop customization of haptic cues. To simplify the creation of haptic feedback devices, we developed a toolkit comprising five wireless, wearable haptic modules that deliver the three most common tactile sensations: vibrotactile, skin-stretch, and probing. These customizable modules can operate individually or together to create multimodal haptic experiences, serving as a platform for rapid prototyping tactile displays. However, despite their accessibility and ease of assembly, the modules remain bulky, rigid, and limited in customization, relying on an off-board computer and technical expertise to function. To create truly body-compliant stretchable haptic electronics, we developed a 3D printed liquid metal (LM) emulsion for wiring that sustains high strains while maintaining electrical connectivity. To fabricate stretchable electronics, the LM emulsion was integrated into a soft polymer matrix through multi-material 3D printing, with manually placed off-the-shelf electronics. The LM emulsion is not conductive upon printing but can be render highly conductive with a single axial strain at low stress (< 0.3 MPa), resulting in activation stresses that are an order of magnitude lower than previous work. The LM emulsion also exhibits a maximum conductivity that is more than 300% higher than that of similar previous work. Its high conductivity and durability under strain make it ideal for stretchable electronics. To integrate the LM emulsion into stretchable electronics, we developed a computer aided fabrication strategy that streamlined the design and production of haptic devices. First, we created an intuitive graphical user interface (GUI) for sketching haptic devices, compatible with direct ink writing. Next, we developed an algorithm to convert circuit schematics into 3D printing commands. This strategy combines direct ink writing with automated pick-and-place of electronics in a single fabrication step. Using this process, we fabricated a wireless, self-powered tactile display comprising a haptic input device and a haptic output device. Together, these devices enable immersive human-to-human interactions by mapping real-time pressure patterns through the input device and generating proportional vibrotactile feedback with the output device. This approach represents a significant step toward enabling rapid prototyping of both haptic devices and haptic experiences. / 2026-02-07T00:00:00Z

2025 / Gallium-based liquid metal alloys (GaLMAs) have widespread applications ranging from soft electronics, energy devices, and catalysis. GaLMAs can be transformed into liquid metal emulsions (LMEs), a composite form with modified rheology, for simpler patterning, processing, and material integration in GaLMA-based device fabrication. One major drawback of using LMEs is reduced electrical conductivity, owing to the oxides that form on the surface of dispersed liquid metal droplets. LMEs thus need to be activated by coalescing liquid metal droplets into an electrically conductive network, which usually involve techniques that subject the LME to harsh conditions. In this thesis, we present a way to coalesce these droplets through a chemical reaction at mild temperatures (T ~ 80°C). This chemical activation is enabled by inclusion of halide compounds that chemically etch the oxide on dispersed microdroplets of eutectic gallium indium (eGaIn). We investigate the use of a covalent halide compound as an activator and elucidate its activation mechanism. Through nuclear magnetic resonance spectroscopy, we discover the ability of eGaIn to catalyze the dehalogenation of our covalent halide activator and confirm through X-ray photoelectron spectroscopy that chemical oxide etching is occurring. Consequently, we establish the mechanism for self-catalyzing chemically coalescing LMEs. We then optimize this emulsion as a functional ink for 3D printing by exploring activator concentrations that maximize post-heat electrical conductivity, compatibility with direct ink writing, and post-activation shape retention. As a result, we select a 3D printable formulation with an electrical conductivity of 1.5 × 10^3 S/cm for further characterization and 3D print parameter optimization. We also explore LME formulations containing halide salt activators, and find that chemically coalescing LMEs can reach a high electrical conductivity (2.4 × 10^4 S/cm) close to that of bulk eGaIn, but at the expense of shorter shelf-life and poorer shape retention. Rheology of the selected covalent halide-based emulsion reveals that the LME is shear thinning and shear yielding. Additionally, it exhibits a high plateau modulus (1.0 × 10^5 Pa) and high yield stress (~2 kPa), thus requiring high pressure and high print velocities, which is desirable for rapid fabrication of GaLMA-based devices. To provide a parameter processing guide for our ink, we construct a print phase diagram describing extrusion pattern types across a normalized print velocity range from 0.45 to 1.35. We also show that our ink can span distances up to 3 mm in length, following a mathematical model for viscoelastic catenaries that predicts an elastic modulus in agreement with experiment. Finally, to demonstrate the utility of our shelf-stable chemically coalescing LME, we incorporate it as a conductive ink in the hybrid 3D printing of custom-designed battery-integrated light emitting diode arrays, demonstrating simpler fabrication of GaLMA-based applications. This technology pioneers a new class of LMEs, providing the material basis for designing future chemically coalescing LMEs and patterning soft metal catalyzed multifunctional materials. / 2026-02-07T00:00:00Z

The following report consists of a master thesis (30 credits) within product development. The thesis is written by Philip Ragnartz and Axel Staffanson, both studying mechanical engineering at Mälardalens University. Developing new components for a production line is costly and time consuming as they must be made from manual measurements and must go through all the conventional manufacturing (CM) steps. Eventual design mistakes will be discovered after the component have been manufactured and tested. To fix the design a completely new component must be designed and therefore double the overall lead time. The purpose of this thesis is to establish how additive manufacturing (AM) can best be used to minimize the cost and lead time in the development of new components. The study was performed by looking at the current product development process in the automotive industry at a large company, here by referred to as company A. 56 components already manufactured at company A´s own tools department was examined and compared to different AM methods. The aim of this was to get a larger pool of data to get an average on production time and cost and see how this differ to the different AM methods. Additionally, two work holders were more closely examined in a case study. Work holder one is a component in the production line that occasionally must be remanufactured. It was examined if this problem could be solved with a desktop plastic printer to hold up for a production batch. Work holder two was the development of a new component, this was to examine the use of printing the component in an early stage impact the development process. The findings from this study is that AM can today not be used in a cost efficient way in manufacturing or development of simple components. This is due to the cost of a metal 3D-printer is still very high, and the building material even higher. This results in components that gets very expensive to make compared to producing them with CM. For design evaluation to be cost efficient there will have to be a design fault in over 12 % of the newly design components for it to be cost effective to print the design for validation before sending it to be manufactured. There are however a lot bigger potential savings in the lead time. Producing the end product with a metal 3D-printer can cut down the lead time up to 85 %. This is thanks to the fact that the printer will produce the component all in one step and therefore not get stuck in between different manufacturing processes. The same goes for design evaluation with printing the component in plastic to confirm the design and not risk having to wait for the component to be manufactured twice. Despite the facts that it is not cost efficient to use AM there are other factors that play an important role. To know that the designed components will work will create a certainty and allow the development process to continue. In some cases it will also allow the designer to improve the design to function better even if the first design would have worked. As AM is expanding machines and build materials will become cheaper. Eventually it will become cheaper to 3D-print even simple components compared to CM. When this occurs, a company cannot simply buy a 3D-printer and make it profitable. There is a learning curve with AM that will take time for the designers to adapt to. Therefore, it is good to start implementing it as soon as possible as it allows for more intricate designs and require experience to do so.

Modern manufacturing processes are under a never ending evolvement. Lowered manufacturing costs, higher part quality, shorter lead times and lower environmental impact are some important drivers for this development. Aluminum die casting is an effective and attractive process when producing components for e.g. the automotive sector. Die casting process development, and hot work tool steel development for the die casting dies has led to the state of the art of die casting today. However, with the disruptive emergence of Additive Manufacturing (AM) of hot work steel alloys, new interesting features such as improved conformal cooling channels inside die casting molds can be produced. The new way to manufacture die casting dies, need basic investigating of the AM produced hot work tool steel properties, and their applicability in this demanding hot work segment. Die casting dies face several detrimental wear mechanisms during use in production, three of which has been isolated and used for testing three AM produced steel alloys and one conventional premium hot work tool steel. The wear mechanisms simulated are; thermal fatigue, static soldering and agitated soldering. The aim is to study the AM produced steels applicability in the die casting process. The tested materials are; Premium AISI H13 grade Uddeholm Orvar Supreme, AM 1.2709, AM UAB1 and AM H13. Based on current investigations the conclusion that can be made is that with right chemistry, and right AM processing, conventional material Uddeholm Orvar Supreme still is better than AM H13. This also complies with the literature study results, showing that conventional material still is better than AM material in general. / Våra moderna tillverkningsprocesser är under ständig utveckling. Drivande motiv är minskade tillverkningskostnader, högre tillverkningskvalitet, kortade ledtider samt minskad miljöpåfrestning. Pressgjutning av aluminium är en effektiv och attraktiv tillverkningsprocess ofta använd inom till exempel fordonsindustrin. Utvecklingen av pressgjutningsteknologin har gått hand i hand med utvecklingen av det varmarbets-verktygsstål som används i gjutformarna (pressgjutningsverktyget). Den utvecklingen har lett till dagens processnivå och branschstandard. Men med den revolutionerande additiva tillverkningsteknologins (AM) intåg, och möjlighet att producera komponenter av varmarbetsstål, kommer nya intressanta möjligheter att integrera komplex geometri så som yt-parallella kylkanaler i verktyget utan att tillverkningskostnaden blir för hög etc. Det nya sättet att producera pressgjutningsverktyg ger upphov till behovet av grundläggande materialundersökningar av sådant AM-material, samt hur tillförlitligt det är i pressgjutningsverktyg med pressgjutningens krävande materialegenskapsprofil. Pressgjutningsverktyg utsätts för många förslitningsmekanismer och för höga laster, tre av dessa mekanismer har isolerats för kontrollerade tester av ett konventionellt material och tre AM materials responser. Förslitningsmekanismerna som efterliknats är; termisk utmattning, statisk soldering och agiterad soldering. Målet med undersökningarna är att studera AM producerade materials lämplighet i pressgjutningsprocessen. De material som testats är konventionella premium varmarbetsstålet Uddeholm Orvar Supreme av typ AISI H13, AM 1.2709, AM UAB1 och AM H13. Undersökningarnas slutsats är att med rätt kemisk sammansättning, och med rätt AM printing parametrar, är konventionellt material fortfarande mer applicerbart i pressgjutning än AM producerat. Den slutsatsen faller väl I samklang med resultaten från mekanisk provning som återspeglas i litteraturstudien, som visade visar att konventionellt material är generellt bättre än AM material.

Purpose: There is today limitations of what is possible to design and in fact produce. In industrial construction the focus is on standardization which impedes an individual design form, which can be considered an architectural quality. The potential of 3Dprinting is growing, which is benefitting design freedom. The goal was to evaluate how 3D-printing in Sweden today could increase architects possibilities at the design process and be production adapted. Method: In a case study at Tengbom in Jönköping, interviews were included with three architects. In addition, a literature review, a telephone interview and a focus group interview formed the basis of the collected material. As an initial phase, a focus group interview was conducted, which resulted in the actors’ opinions about 3D-printing. The architect interviews contributed with high credibility regarding architectural qualities, which together with the other collection methods gave answers to the studies questions. Findings: The study shows that it is possible to print building components in Sweden. However it is not possible, with 3D-printing, to produce entire buildings. It can be shown that there are obstacles for the introduction of the technology, such as economy, Swedish laws and lack of knowledge. These should be reviewed to allow 3D-printing as a manufacturing method. With Rapid Ornament Production larger architectural qualities will conduce to, where 3D-printing allows unique solutions. Solutions no other technology can achieve. Implications: Customized and varied buildings can be achieved thanks to 3D-printing. Building components such as light weight walls, ornaments and details can be produced in Sweden today. One advantage of 3D-printing as a technology, is that it provides greater freedom between design and production. For further development of 3Dprinting a greater knowledge is recommended for industry stakeholders, regarding the drawing tools as well as the 3D-printing technology. Limitations: The result is applicable to architects, working at architectural offices similar to Tengbom in Jönköping. There have not been deeper studies regarding of printing technologies, finances, materials, time or law. A case study as research strategy entails an interpretation of the opinions, which limits the generalization of the results. Keywords: 3D-printing, design, production, architectural qualities, possibilities, limitations, industrial construction. / Syfte: Det finns idag begränsningar för vad som är möjligt att utforma och faktiskt producera. I industriellt byggande ligger fokus på standardisering som försvårar ett individuellt formspråk, vilket kan anses vara en arkitektonisk kvalitet. Potentialen för 3D-printing växer, vilket gynnar utformningsfriheten. Målet var att utvärdera hur 3D-printing i Sverige idag skulle kunna öka arkitektens möjligheter vid utformning och vara produktionsanpassat. Metod: I en fallstudie på Tengbom i Jönköping, ingick intervjuer med tre arkitekter. Utöver detta har en litteraturstudie, telefonintervju och en fokusgrupp legat till grund för insamlat material. Som ett inledande skede genomfördes en fokusgrupp, vilken resulterade i aktörers åsikter om 3D-printing. Arkitektintervjuerna bidrog med hög trovärdighet gällande arkitektoniska kvaliteter, vilket tillsammans med övriga insamlingsmetoder gav svar på studiens frågeställningar. Resultat: Studien visar att det är möjligt att skriva ut byggkomponenter i Sverige. Dock är det inte möjligt att med 3D-printing tillverka hela byggnader. Det kan påvisas att det finns hinder för införandet av tekniken, så som ekonomi, svensk lagstiftning samt bristande kunskap. Dessa bör ses över för att möjliggöra 3D-printing som tillverkningsmetod. I och med Rapid Ornament Production kan större arkitektoniska kvaliteter främjas, där 3D-printing möjliggör unika lösningar. Lösningar ingen annan teknik kan åstadkomma. Konsekvenser: Kundanpassad och varierad bebyggelse kan åstadkommas tack vare 3D-printing. Byggkomponenter så som, lättväggar, ornament och detaljer kan tillverkas i Sverige idag. En fördel med 3D-printing som teknik, är att den ger större frihet mellan projektering och produktion. För vidare utveckling av 3D-printing rekommenderas ökad kunskap för branschens aktörer gällande ritverktygen samt 3D-printings-tekniken. Begränsningar: Resultatet är applicerbart för arkitekter, verksamma vid arkitektkontor av liknande storlek som Tengbom i Jönköping. Det har inte genomförts djupare studier gällande utskriftstekniker, ekonomi, material, tid eller juridik. Fallstudie som undersökningsstrategi innebär en tolkning av åsikter, vilket begränsar generaliseringen av resultatet. Nyckelord: 3D-printing, utformning, produktion, arkitektoniska kvaliteter, möjligheter, begränsningar, industriellt byggande.

<p>There has been a long-standing need in the marketplace for the economic production of small lots of components that have complex geometry. A potential solution is additive manufacturing (AM). AM is a manufacturing process that adds material bottom-up. It has the distinct advantages of low preparation cost and high geometric creation capability. Components fabricated via AM are now being selectively used for less-demanding applications in motor vehicles, consumer products, medical products, aerospace devices, and even some military projects.</p><p><br></p> <p>For engineering applications, high value-added components require consistency in the fatigue properties. However, components fabricated by AM have large variation in the fatigue properties compared to those by conventional manufacturing processes. To alleviate unpredictable catastrophic failures of components, it is essential to study and predict fatigue life. Previous study reported that fatigue crack initiation process accounts for a large portion of fatigue life, especially for low loading amplitude and high cycle fatigue. However, this major portion of fatigue life prediction is mostly ignored by main stream researchers working on fatigue modeling. For industrial applications, engineers often specify a lower stress condition to obtain a higher safety factor. Under these circumstances, fatigue crack initiation becomes even more important, so it is essential to further study of crack initiation.</p><p><br></p> <p>The objective of this research is to develop a fatigue crack initiation model for metal components produced by AM. To improve life prediction accuracy, the model must incorporate the effect of different microstructures, which are typically produced by AM due to a large number of repetitive cycles of re-heating and re-cooling processes. To fulfill this objective, the tasks are separated into three studies: (1) developing a temperature model to simulate temperature history, (2) modeling the component’s microstructure for the potential crack initiation zone, and (3) developing a fatigue crack initiation model for life estimation. A summary of each task is provided in the following.</p> <p>First, the role of temperature model is to understand the mechanism that leads to the variation of microstructures. The existing temperature models are computationally expensive to obtain an accurate prediction of the temperature history due to repetitive heating and cooling. The main reason is that these models considered entire boundary conditions of all the material points. In this section, we proposed and employed the concept of effective computation zone, which can save the computational time significantly for AM process. </p><p><br></p> <p>Second, it is critical to include the effect of microstructure in the fatigue life model since the microstructure variation at different locations within the real AM component is large. The grain size variation is modeled by using representative volume element, which is defined as a volume of heterogeneous material that is sufficiently large to be statistically representative of the real component’s microstructure. Regarding phase transformation, a continuous cooling transformation (CCT) diagram is a useful tool that can be used with a thermal model for microstructure design and manufacturing process control. However, traditional CCT diagrams are developed based on slow and monotonic cooling processes such as furnace cooling and air cooling, which are greatly different from the repetitive heating and cooling processes in AM. In this study, a new general methodology is presented to create CCT diagrams for materials fabricated by AM. We showed that the effect of the segmented duration within the critical temperature range, which induced precipitate formation, could be cumulative. </p><p><br></p> <p>Third, the existing fatigue crack initiation life model has poor accuracy. One of the reasons for the poor accuracy is the coefficients change due to the variation in microstructure is not accounted for. In this section, a semi-empirical fatigue crack initiation model is presented. The important coefficients include maximum persistent slipband width, energy efficiency coefficient, resolved shear stress and plastic slip rate per cycle. These coefficients are modeled and determined as a function of microstructure, which can improve the accuracy of life estimation.</p><p><br></p> <p>The contribution of this study is to provide a new engineering tool for designing the melting AM process based on scientific research. With this tool, the fundamental mechanism contributing to a large variation of the fatigue life of the metal components made by AM process can be understood, attributed, predicted and improved. The seemly ‘stochastic’ nature of fatigue life of the AM components can be changed to be more deterministic and predictable. This approach represents a major advance in fatigue research on AM materials. The model developed is considered as a tool for research, design, and control for laser-based AM process applications. </p>

The diploma thesis is focused on 3D printing of composites parts. Thesis deals with methods of additive manufacturing and describes principle of selected 3D printing technologies. In addition to additive technologies, the theoretical part presents an overview of composite materials and methods of composite production. Then there are four concepts that lead to 3D printing of continuous fiber reinforced composites components. The final concept is selected according to multi-criteria analysis and then designed. Designed extruder allows 3D printing of composite materials. The principle of the function consists of fiber impregnation by matrix inside the heat chamber and then deposition of composite on printing platform. The extruder also consist of fiber cutting mechanism. The extruder's ability is verified by the experiment.

The current regulation for Medical Devices (MDR) entered into force on 26 May 2021, which has entailed major changes to relevant legislation for in-house production of medical devices in healthcare. The relevance for updating existing, or the development of new standards is currently not well documented and determined and the aim of this report is to make recommendations for how the development of standards may be improved and how departments of medical technology (DMT) in practice apply standards at in-house production of medical devices. The sub-areas that are dealt with in in-house production are reprocessing of single use devices, 3D printing and medical technology software. How standards are used to support departments of medical technology in manufacturing in these areas is described and analyzed in this report. Information for the study was collected through semi-structural interviews with several DMTs and relevant authorities. The information was analyzed, discussed, and compared with previous research. The use of standards varied between DMTs, but all interviewees used standards to some extent. The study concluded that there was an interest from DMTs and a potential need to update existing standards and the production of new standards to meet DMT’s needs. / Nuvarande förordning för medicintekniska produkter (MDR) trädde i kraft den 26 maj 2021, vilket har inneburit stora förändringar på relevant lagstiftning för egentillverkning av medicintekniska produkter inom sjukvården. Relevansen för uppdatering av existerande, alternativt utveckling av nya standarder är i nuläget ej väl dokumenterat och klarlagt och målet med denna rapport är att komma med rekommendationer för hur utveckling av standarder kan förbättras samt hur medicintekniska avdelningar (MTA) i praktiken applicerar sig av standarder vid egentillverkning av medicintekniska produkter. De delområden som behandlas inom egentillverkning är reprocessing av engångsartiklar, 3D-printing och medicinteknisk mjukvara. Hur standarder används som stöd av MTA vid tillverkning inom dessa områden beskrivs och analyseras i denna rapport. Information för studien insamlades genom semi-strukturella intervjuer med flera MT-avdelningar och relevanta myndigheter.Informationen analyserades, diskuterades och jämfördes med tidigare forskning. Användandet av standarder varierade mellan MTA, men alla intervjuade använde standarder i någon utsträckning. Det framkom i studien både ett intresse för uppdatering av existerande standarder och framställning av nya standarder för att bemöta MTAs behov.

The industrial robot is a flexible and cheap standard component that can becombined with a milling head to complete low accuracy milling tasks. Thefuture goal for researchers and industry is to increase the milling accuracy, suchthat it can be introduced to more high value added operations.The serial build up of an industrial robot bring non-linear compliance andchallenges in vibration mitigation due to the member and reducer design. WithAdditive Manufacturing (AM), the traditional cast aluminum structure couldbe revised and, therefore, milling accuracy gain could be made possible due tostructural changes.This thesis proposes the structural changes that would improve the millingaccuracy for a specific trajectory. To quantify the improvement, first the robothad to be reverse engineered and a kinematic simulation model be built. Nextthe kinematic simulation process was automated such that multiple input parameterscould be varied and a screening conducted that proposed the mostprofitable change.It was found that a mass decrease in any member did not affect the millingaccuracy and a stiffness increase in the member of the second axis would increasethe milling accuracy the most, without changing the design concept. To changethe reducer in axis 1 would reduce the mean position error by 7.5 % and themean rotation error by 4.5 % approximately, but also reduces the maximumspeed of the robot. The best structural change would be to introduce twosupport bearings for axis two and three, which decreased the mean positioningerror and rotation error by approximately 8 % and 13 % respectively. / En industrirobot är en anpassningsbar och relativt billig standardkomponent.Den kan utrustas med ett fräshuvud för att genomföra fräsoperationer med låg noggrannhet. Det framtida målet för forskare och industri är att öka noggrannheten vid fräsning så att dess användningsområde kan utökas till ändamål som kräver högre precision.Den seriella uppbyggnaden av en industrirobot medför icke-linjär styvhet och därmed utmaningar vid vibrationsdämpning. Detta på grund av den strukturella uppbyggnaden då en industrirobot kan förenklat sägas vara uppbyggd av balkelement som i ledpunkterna kopplas samman av växellådor. Med friformsframställning kan en mer komplex struktur erhållas jämfört med traditionellt gjuten aluminiumkonstruktion därmed skulle en ökad noggrannhet vid fräsning kunna uppnås.Det här examensarbetet föreslår strukturella ändringar som skulle kunna öka noggrannheten vid fräsning för en specifik fräsbana. För att kvantifiera förbättringen, var det först nödvändigt att utgående från tillgänglig data konstruktion en specific robot samt att bygga en kinematisk modell. Därefter automatiserades beräkningsflödet så att ett flertal indata kunde varieras. Detta resulterande i en kombinationsstudie som visade den mest gynsamma strukturella förändringen.Det visade sig att en minskning av balkelementens massa inte påverkade nogrannheten. Att öka styvheten i balkelementet från den andra axeln skulle d¨aremot öka nogrannheten mest utan att behöva ändra robotens uppbyggnad.Att byta växellåda i första axeln kan öka positionsnogrannheten med nära 7.5 % och rotationsnoggrannheten med cirka 4.5 % men ändringen sänker samtidigt den maximala hastigheten. Den bästa strukturella förändringen vore att introducera ett stödlager vid axel två respektive tre, vilket skulle förbättra positionsnogrannheten med cirka 8 % och rotationsnogrannheten med nära 13 %.