Browsing by Author "Partanen, Jouni"

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  • 3D printed replacements for lead in dental radiography shielding
    (2022-06-13) Andersson, Kia
     Insinööritieteiden korkeakoulu | Master's thesis
    X-ray shielding has a crucial part in dental radiography. The current shielding utilises lead, that attenuates x-rays well. However, the use of lead is no longer recommended due to the toxicity of the material. Additionally, the geometry of the lead is difficult to optimise, which leads to excess use of shielding. Therefore, the aim of this thesis was to analyse and compare suitable 3D printable replacement materials for lead shielding. The suitability of the candidate materials as shielding was analysed based on theoretical attenuation values. The two best commercial materials based on the theoretical values were selected: tungsten powder and tungsten-PLA filament. Rectangular sheets of these materials were 3D printed. The tungsten powder was printed by powder bed fusion and the tungsten-PLA filament by material extrusion. The suitability of the materials was verified by measuring the attenuation of x-rays by the rectangular prints. The results showed that tungsten powder attenuated x-rays approximately 15% better than lead, whereas the tungsten-PLA filament attenuated 30% less than lead. The 3D printing did not significantly affect the attenuation. However, a distortion in the print path or higher energy x-rays might impact the attenuation, which encourages further testing of 3D printed shielding. The results show great potential in adopting 3D printed tungsten-based materials for x-ray shielding. This alternative solution would be beneficial due to its nontoxicity and optimised geometry by utilising metal printing in a new application.
  • 3D printing - increasing competitiveness in technical maintenance
    (2017-05-08) Halinen, Juho
     Insinööritieteiden korkeakoulu | Master's thesis
    The purpose of this thesis is to find out how additive manufacturing (AM, 3D printing) can be used in technical maintenance business and to create a starting point for adopting AM in a maintenance provider’s business. To study this, the current state of AM technology and how it relates to technical maintenance is surveyed. In addition, a plastic jig was manufactured using 3D printing. This jig could help to reduce down time of a process and also gives the company more information on the practical side of AM. This thesis also includes helpful charts and information that can be used to spread AM knowledge throughout a company. Additive manufacturing technology’s current state is surveyed from textbooks, articles and studies. Machine manufacturers’ and service providers’ web pages are also utilized. At the moment 3D printing can be used to manufacture end parts and spare parts that directly replace old parts made of different plastics and metals. The AM knowledge is combined with the requirements and characteristics of technical maintenance and especially from the view point of a service provider. Technical maintenance’s special characteristics include: the importance of supply chain and delivery time; difficulty of acquiring CAD models; lack of testing facilities and possibilities. In technical maintenance, the availability of spare parts at the right time and at a low price is of the utmost importance. AM can produce parts on demand with a simple supply chain provided that some preparations are done. Requirements for parts in technical maintenance vary a lot as the customer companies can include for example paper mills, food manufacturers and power plants. A wide variety of parts means that there are bound to be suitable applications for AM. However, it also means that locating these is difficult. Finding suitable applications should be done from the sites and factories instead of a centralized group looking for applications. The results show that while there remains problems in AM’s adoption to technical maintenance, applications can be found. One of the biggest barriers to adoption is the difficulty of quality assurance and lack of testing possibilities.
  • 3d printing of a continuous carbon fiber reinforced bronze-matrix composite using material extrusion
    (2025-01-15) Mousapour, Mehrdad; Kumar, S. Siddharth; Partanen, Jouni; Salmi, Mika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The main objective of this study is to investigate, for the first time, the feasibility of 3d printing a continuous carbon fiber (CCF) reinforced metal matrix composite using a cost-effective material extrusion (MEX) technology. Notably, this paper presents a detailed analysis of the microstructure and mechanical and physical properties of a bronze matrix composite reinforced with CCF. The results reveal that CCF significantly impedes the expected densification levels of the composite's structure, causing extensive gaps between the bronze particles. However, despite the high porosity level, the composite's electrical conductivity remains relatively high, demonstrating the limited negative impact of the CCF material on the composite's conductivity. Moreover, mechanical evaluations were performed through 3-point bending and tensile tests, highlighting the composite material's advantages and limitations. The results show that the composite material exhibits an improved yield stress of 76 %, increased ultimate tensile strength of 20 %, and an extended fracture strain of 30 %. However, the flexural strength decreases by 23 % due to the presence of massive gaps formed by CCF.
  • 3D-Printed Thermoset Biocomposites Based on Forest Residues by Delayed Extrusion of Cold Masterbatch (DECMA)
    (2021-10-18) Trifol, Jon; Jayaprakash, Siddharth; Baniasadi, Hossein; Ajdary, Rubina; Kretzschmar, Niklas; Rojas, Orlando J.; Partanen, Jouni; Seppälä, Jukka V.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We developed a 3D-printing process based on thermoset biocomposites termed Delayed Extrusion of Cold Masterbatch (DECMA). DECMA is a processing method, based on controlling the degree of curing, that takes some responsibility of the 3D printing from materials and as such can be used to 3D print otherwise unprintable materials. First, a masterbatch was produced by mixing a bio-based resin (bioepoxy) and sawdust and lignin. This paste was partially cured at room temperature until reaching an apparent viscosity suitable for extrusion (≈105 mPa·s at 1 s-1). The system was next cooled (5-10 °C) to delay subsequent hardening prior to 3D printing. The printability of the biocomposite paste was systematically investigated and the merits of the delayed extrusion, via DECMA, were assessed. It was found that DECMA allowed the revalorization of sawdust and lignin via 3D printing, as direct printing led to failed prints. Our approach afforded cost-effective, shear-thinning dopes with a high bio-based content (58-71%). The bio-based 3D-printed materials demonstrated good machinability by computer numerical control (CNC). Overall, the benefits of the introduced DECMA method are shown for processing bio-based materials and for on-demand solidification during additive manufacturing.
  • 3D-tulostettujen preoperatiivisten mallien verifiointi optisella ja koordinaattimittauskoneella
    (2017-06-12) Leppälä, Sami
     Insinööritieteiden korkeakoulu | Master's thesis
    3D-tulostaminen on mahdollistanut ja helpottanut täysin uudenlaisten mallien valmistamista. Valmistusmenetelmät ovat vastanneet erityisesti lääketieteen vaatimuksiin. Preoperatiiviset mallit auttavat toimenpidesuunnittelussa; niillä voidaan tehdä harjoituksia ja kokeita ennen varsinaista toimenpidettä. Tavoitteena on mallien avulla tehostaa lääketieteellisten operaatioiden tehokkuutta ja näin lopulta parantaa potilasturvallisuutta. Erilaiset 3D-tulostusmenetelmät ja mallien monipuoliset ja usein hankalat muodot vaikeuttavat niiden laadun verifiointia perinteisin mittausmenetelmin. Teollisuudessa koordinaattimittauskoneet ovat de facto -standardimittalaitteen asemassa, mutta optisten mittalaitteiden edut, kuten nopeus ja joustavuus, ovat lisänneet niiden suosiota. Tässä tutkimuksessa selvitetään erilaisilla 3D-tulostusmenetelmillä tuotettujen lääketieteellisten leukaluumallien laatua ja mittatarkkuutta. Mallit on tuotettu kaupallisesti tarjolla olevilla tulostusmenetelmillä: pursotuksella, sideaineen suihkutuksella, materiaalin suihkutuksella ja jauhepetisulatuksella. Verifiointimenetelminä on käytetty mallien visuaalista tarkastelua, 3D-skannausta optisella mittalaitteella ja koordinaattimittausta. Vertailukohtana fyysisille malleille on käytetty leukaluun CAD-mallia. Tutkimuksen tavoitteena on selvittää, miten kunkin tulostusmenetelmän ominaispiirteet näkyvät lopputuotteessa ja millä menetelmillä malleja voidaan järkevästi verifioida.
  • 4D mallinnuksen hyödyntäminen investointiporjekteissa
    (2023-06-12) Hannus, Juho
     Insinööritieteiden korkeakoulu | Master's thesis
  • 4D-printed continuous carbon fiber reinforced shape memory polymer composite in medical supports
    (2022-01-24) Väänänen, Antti
     Insinööritieteiden korkeakoulu | Master's thesis
    Aalto University Advanced Manufacturing and Materials research group has a long background in additive manufacturing (AM). Especially they have studied how AM can be utilized in medical applications. In the group, there are experience of for example multi-material extrusion and shape memory metals. Now the goal is to develop this expertise to purer 4D printing and expand the materials to composites. In this study 4D-printed continuous carbon fiber (CCF) reinforced shape memory polymer (SMP) composite is researched. The printability of the composite is studied and improved. Also, the effect of continuous carbon fiber infill into the shape memory effect (SME) of the used SMP is examined. In this thesis was found out that 4D-printed continuous carbon fiber reinforced shape memory polymer can give new possibilities to body-external prostheses because of its ability to change its shape while having good mechanical properties thanks to the reinforcing fibers. The printability of the material combination and the printing quality of the fibers are the main two things that need to be researched more to achieve a suitable level for further use of this technology. Totally 20 different parameters were changed to achieve better print quality and printability. Clogging of SMP hotend was a significant issue in the progress of this work. A new extension part was made to hinder clogs and an idea of modifying the hotend is shown. In the shape memory recovery test were found that CCF strengthens the shape memory recovery capabilities of the sample. Overall, this thesis presents novel insights into the printing of continuous fiber-reinforced shape memory polymer composites with the in-situ co-extrusion method.
  • Additive Manufacturing in Finland: Recommendations for a Renewed Innovation Policy
    (2017) Flores Ituarte, Inigo; Salmi, Mika; Ballardini, Rosa Maria; Tuomi, Jukka; Partanen, Jouni
     A4 Artikkeli konferenssijulkaisussa
    The objective of this research is to define an optimal innovation policy and funding strategy to improve Additive Manufacturing (AM) capabilities in Finnish companies. To do so, we present an international review of innovation programs in the area of AM. In addition, the study replied upon a survey prepared to evaluate factors for AM implementation. The ultimate goal is to help in the definition of a national policy strategy in the area of AM based on the characteristics of the Finnish industrial ecosystem. The methodology and data collection method involved defining the taxonomy of Finnish AM industry. The target group of the survey was a population of AM experts, and individuals with knowledge on AM and industrial processes. Overall, the survey revealed that research and innovation activities are well positioned in Finland. In order for future innovation policies to further support developments in the field, we estimated that policy strategies need to generate about 6-8 M€/year in national and EU- funding instruments for AM technology transfer, development, and innovation activities. Efforts should be targeted towards strengthening uses of AM in final production. In fact, only 36% of Finnish respondents declared to use AM for final production, while leading countries in AM use it in average more than 50%. Another area in need of development in Finland is the use of AM high performance materials. Moreover, outsourcing of AM services in Finland is 23 percentage point higher in national and 13 percentage point higher in international outsourcing to service bureaus and suppliers. In this regard, future policies and funding strategies should maintain the created momentum. However, there is a need to acquire high-end research and industrial equipment to stimulate AM integration to the existing production systems. This in the end can trigger the creation of new products, processes and intellectual property, enabling innovation and competitive advantage.
  • Additive Manufacturing in Production: A Study Case Applying Technical Requirements
    (2015) Flores, Iñigo; Coatanea, Eric; Salmi, Mika; Tuomi, Jukka; Partanen, Jouni
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Additive manufacturing (AM) is expanding the manufacturing capabilities. However, quality of AM produced parts is dependent on a number of machine, geometry and process parameters. The variability of these parameters affects the manufacturing drastically and therefore standardized processes and harmonized methodologies need to be developed to characterize the technology for end use applications and enable the technology for manufacturing. This research proposes a composite methodology integrating Taguchi Design of Experiments, multi-objective optimization and statistical process control, to optimize the manufacturing process and fulfil multiple requirements imposed to an arbitrary geometry. The proposed methodology aims to characterize AM technology depending upon manufacturing process variables as well as to perform a comparative assessment of three AM technologies (Selective Laser Sintering, Laser Stereolithography and Polyjet). Results indicate that only one machine, laser-based Stereolithography, was feasible to fulfil simultaneously macro and micro level geometrical requirements but mechanical properties were not at required level. Future research will study a single AM system at the time to characterize AM machine technical capabilities and stimulate pre-normative initiatives of the technology for end use applications.
  • Additive manufacturing in spare parts supply chains
    (2013) Haghighat Khajavi, Siavash
     School of Science | Master's thesis
  • Additive manufacturing in the spare parts supply chain : hub configuration and technology maturity
    (2018-10-08) H. Khajavi, Siavash; Holmström, Jan; Partanen, Jouni
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Purpose: Innovative startups have begun a trend using laser sintering (LS) technology patents expiration, namely, by introducing LS additive manufacturing (AM) machines that can overcome utilization barriers, such as the costliness of machines and productivity limitation. The recent rise of this trend has led the authors to investigate this new class of machines in novel settings, including hub configuration. There are various supply chain configurations to supply spare parts in industrial operations. This paper aims to explore the promise of a production configuration that combines the benefits of centralized production with the flexibility of local manufacturing without the huge costs related to it. Design/methodology/approach: This study quantitatively examines the feasibility of different AM-enabled spare parts supply chain configurations. Using cost data extracted from a case study, three scenarios per AM machine technology are modeled and compared. Findings: Results suggest that hub production configuration depending on the utilized AM machines can provide economic efficiency and effectiveness to reduce equipment downtime. While previous studies have suggested the need for AM machines with efficiency for single part production for a distributed supply chain, the findings in this research illustrate the positive relationship between multi-part production capability and the feasibility of a hub manufacturing configuration establishment. Originality/value: This study explores the promise of a production configuration that combines the benefits of centralized production with the flexibility of local manufacturing without the huge costs related to it. Although the existing body of knowledge contains research on production decentralization, research on various levels of decentralization is lacking. Using a real-world case study, this study aims to compare the feasibility of different levels of decentralization for AM-enabled spare parts supply chains.
  • Additive manufacturing needs and practices in the Finnish industry
    (2014-06-09) Chekurov, Sergei
     Insinööritieteiden korkeakoulu | Master's thesis
    The purpose of this thesis is to present the current needs and practices of additive manufacturing in the Finnish industry. To obtain the necessary information, a survey of eight companies was carried out. An introduction to additive manufacturing and its applications is given to give the reader a better understanding of the survey. A survey was designed and the process explained. The main tool, the questionnaire, was chosen to be the best option to conduct the survey and was designed to consist of a combination of open questions and scale questions. The questionnaire was presented to eight companies of varying size in the research and development industry. Fifteen people from these companies were chosen for the survey. All of the qualitative answers were analytically quantified and expanded upon. The findings of the survey were compared to the findings of other worldwide reports. The results obtained through this study include data regarding familiarity of AM technologies, ownership of machinery, outsourcing practices, and general perception of AM in Finnish companies. It was found that while the Finnish industry is somewhat lagging behind on some fronts of AM usage, the trend is showing that AM is becoming more widely understood and its usage in more advanced applications is on the rise.
  • Additively manufactured high-performance counterflow heat exchanger
    (2019-03-01) Chekurov, Sergei; Kajaste, Jyrki; Saari, Kari; Kauranne, Heikki; Pietola, Matti; Partanen, Jouni
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The purpose of this article is to demonstrate that additive manufacturing is a viable method for producing counterflow heat exchangers that have a very high power to volume ratio. For this study, a heat exchanger with 144 flow channels in a checkerboard pattern was designed and additively manufactured from AlSi10Mg. The heat exchanger was tested by measuring the heat transfer between two liquids in a counterflow set-up, where it reached exceptionally high performance when considering its volume and weight. The heat transfer properties of the heat exchanger were verified analytically through calculations, which identified that the high surface roughness of the channels provides a significant improvement in heat transfer properties. The heat transfer capabilities were measured on two separate occasions to investigate the possible change of properties of additively manufactured heat exchangers over time when used with tap water. A moderate decrease in heat flow and increase in pressure drop were noted between the measurements. The deterioration of heat transfer capabilities could present a significant challenge for additively manufactured heat transfer applications and will be closely examined in future research.
  • Additively Manufactured Parametric Universal Clip-System: An Open Source Approach for Aiding Personal Exposure Measurement in the Breathing Zone
    (2020-10-01) Kukko, Kirsi; Akmal, Jan Sher; Kangas, Anneli; Salmi, Mika; Björkstrand, Roy; Viitanen, Anna-Kaisa; Partanen, Jouni; Pearce, Joshua
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Design for additive manufacturing is adopted to help solve problems inherent to attaching active personal sampler systems to workers for monitoring their breathing zone. A novel and parametric 3D printable clip system was designed with an open source Computer-aided design (CAD) system and was additively manufactured. The concept was first tested with a simple clip design, and when it was found to be functional, the ability of the innovative and open source design to be extended to other applications was demonstrated by designing another tooling system. The clip system was tested for mechanical stress test to establish a minimum lifetime of 5000 openings, a cleaning test, and a supply chain test. The designs were also tested three times in field conditions. The design cost and functionalities of the clip system were compared to commercial systems. This study presents an innovative custom-designed clip system that can aid in attaching different tools for personal exposure measurement to a worker’s harness without hindering the operation of the worker. The customizable clip system opens new possibilities for occupational health professionals since the basic design can be altered to hold different kinds of samplers and tools. The solution is shared using an open source methodology.
  • Ainetta lisäävien menetelmien käyttö metallisissa varaosissa varaosaliiketoiminnassa
    (2016-05-16) Koskinen, Ari
     Insinööritieteiden korkeakoulu | Master's thesis
    Aktiivinen ylläpito pidentää laitteiden elinikää usein merkittävästi. Vaikka laitteen varsinainen tuotanto on voinut loppua kymmeniä vuosia aikaisemmin, varaosien kysyntä saattaa silti yhä olla tasaista. Varaosien tarvetta ja saatavuutta tulisi kyetä ennustamaan etukäteen, jotta varastointikustannukset voitaisiin minimoida. Sen sijaan, että kymmenien vuosien osatarve valmistettaisiin varastoon säilytettäväksi, voitaisiin osat valmistaa myös tarveperustaisesti. Kuitenkin esimerkiksi valettujen kappaleiden valmistuksessa käytettävillä muoteilla on tietty kestoikä, jonka jälkeen nämä tulisi uusia. Siten yksittäisen osan valmistaminen voi tulla ajoittain erittäin kalliiksi. Varaosaliiketoiminnassa tarvitaankin joustavia valmistusmenetelmiä, joiden avulla kappaleet saadaan ripeästi valmistettua sopivalla yksikkökustannuksella Tässä diplomityössä tutkittiin metallisten varaosien tarveperustaista valmistamista ainetta lisäävin menetelmin. Kokeellisena tutkimuksena valmistettiin jauhepetitekniikkaa käyttäen kaksi varaosaa, kotelo sekä akseli. Tavoitteena oli tutkia, miten kappaleiden laatu, kustannukset sekä toimitusajat vertautuvat perinteisesti käytettyihin valmistusmenetelmiin ja osien suoravalmistukseen aihiosta koneistamalla. Lisäksi vertailua tehtiin kahden eri jauhepetitekniikkatoimittajan välillä. Laatua tarkasteltiin mittaamalla kappaleiden massaa, pinnankarheutta, pintakovuutta, mikrorakennetta, vetolujuutta, iskusitkeyttä, kemiallista koostumusta, mittatarkkuutta, öljyn läpäisevyyttä sekä koneistettavuutta. Valmistuskustannuksia sekä toimitusaikaa tutkittiin tilausprosessin tietojen kautta. Tutkimuksessa havaittiin, ettei näille kappaleille AM-valmistuksen mittatarkkuus ollut riittävä, vaan ne tuli koneistaa ennen käyttöä. Lisäksi esimerkiksi akselissa jouduttiin hyödyntämään toimittajan ehdottamaa maraging-terästä, sillä alkuperäisiä vastaavia materiaaleja ei ollut saatavilla jauhepetitekniikassa. Näin ollen AM-valmistetun akselin pinta ei ollut yhtä kovaa verrattuna alkuperäismateriaaliin. Lisäksi mitattujen alumiinin kimmomoduulien havaittiin eroavan huomattavasti toimittajan odotusarvosta, joka toimittajan mukaan saattoi johtua materiaaliominaisuuksien anisotropiasta. Myös muissa materiaaliominaisuuksissa havaittiin eroa alkuperäismateriaaleihin nähden. Näin ollen jauhepetitekniikan soveltuvuutta tietyn osan valmistukseen tulee harkita ja koestaa erikseen. Tutkittujen kappaleiden osalta näyttäisikin taloudellisesti kannattavammalta suoravalmistaa ne tarveperustaisesti aihiosta koneistamalla.
  • Alihankittavien koneistuskappaleiden valmistettavuuden suunnittelu
    (2024-05-20) Lindman, Sakari
     Insinööritieteiden korkeakoulu | Master's thesis
    Tuotannon ja suunnitelun yhteistyö uusien tuotteiden luomisessa on olennaista kustannustehokkaiden konstruktioiden luomiseksi. Alihankintaprosessin tuomat kommunikaatihäiriöt estävät tätä yhteistyötä olennaisesti sisäiseen valmistukseen verrattuna. Työn tavoitteena on tutkia alihankittavien koneistuskappaleiden uudelleensuunnittelun potentiaalia hankintakustannusten ja toimitusaikojen pienentämiseksi. Työn teoriaosuudessa käsitellään tuotteen valmistettavuuden ja kustannuksen muodostumista sekä alihankkijan ja päähankkijan suunnitteluosaston yhteistyöprosesseja. Lisäksi työ sisältää case-esimerkin eräästä komponentin uudelleensuunnittelusta yhteistyössä alihankintayrityksen kanssa. Uudelleensuunnittelun seurauksena komponentin valmistuskustannuksia onnistuttiin madaltamaan keskimäärin 12\% sekä valmistuksen hitsausvaiheen kestoa jopa 90\%. Tämän lisäksi jatkuvan yhteistyöprosessin luomiselle suunnitteluosaston sekä alihankintayritysten välillä todettiin olevan tarve.
  • Analysing performance and resource consumption variability using simulation of diverse 3D-printed nozzle designs for efficient cleantech operations in the mining industry
    (2024) Ur Rehman, Obaid
     Insinööritieteiden korkeakoulu | Master's thesis
    In the field of innovation, creating and testing protypes can be an expensive process. Recent developments in manufacturing technology, especially in additive manufacturing and Computer Aided Design (CAD), have significantly transformed the process of creating and testing prototypes, respectively. The objective of this work was to predict the performance of a metal 3D printable, novel nozzle design using CAD modelling. The aim was to adopt a step-by-step approach, solving a simple 2D CAD model initially and gradually adding complexity whilst also identifying the optimal computational model. The final step was to develop a comprehensive 3D model simulation of the nozzle which best predicts the real-world behaviour. A further consideration in the testing of the nozzle was resource consumption. However, simulations of three 2D nozzles with varying air and water inlet dimensions were solved using the Mixture multiphase model and the K- ε turbulent model. As expected, increasing the inlet size resulted in increased pressure at the impact point of the spray. Unfortunately, due to unavailability of required expertise and computational resources, the floating-point exception error for the 3D model in Ansys could not be solved. Although the 3D modelling was not a success, the multiphase and turbulent models were identified as being the most suitable for use, and this was verified through successful modelling of the 2D nozzles. This study therefore serves as a strong starting point for the design and development of multiphase-flow noz-zles for industrial application.
  • Anisotropic Plastic Behavior of Additively Manufactured PH1 Steel
    (2021-04-01) Liu, Wenqi; Li, Zinan; Bossuyt, Sven; Forsström, Antti; Que, Zaiqing; Björkstrand, Roy; Salmi, Mika; Partanen, Jouni; Lian, Junhe
     A4 Artikkeli konferenssijulkaisussa
    Metals made by additive manufacturing (AM) have intensely augmented over the past decade for customizing complex structured products in the aerospace industry, automotive, and biomedical engineering. However, for AM fabricated steels, the correlation between the microstructure and mechanical properties is yet a challenging task with limited reports. To realize optimization and material design during the AM process, it is imperative to understand the influence of the microstructural features on the mechanical properties of AM fabricated steels. In the present study, three material blocks with 120×25×15 mm3 dimensions are produced from PH1 steel powder using powder bed fusion (PBF) technology to investigate the anisotropic plastic deformation behavior arising from the manufacturing process. Despite being identical in geometrical shape, the manufactured blocks are designed distinguishingly with various coordinate transformations, i.e. alternating the orientation of the block in the building direction (z) and the substrate plate (x, y). Uniaxial tensile tests are performed along the length direction of each specimen to characterize the anisotropic plastic deformation behavior. The distinctly anisotropic plasticity behavior in terms of strength and ductility are observed in the AM PH1 steel, which is explained by their varied microstructure affected by the thermal history of blocks. It could also be revealed that the thermal history in the AM blocks is influenced by the block geometry even though the same process parameters are employed.
  • Assessing the economic implications of part consolidation in additive manufacturing through optimization analysis.
    (2024-09-06) Nasabi, Manjunath Tejappa
     School of Engineering | Master's thesis
    This thesis investigates the benefits and challenges of part consolidation and topology optimization in view of additive manufacturing for engineering applications by presenting case studies with the aim of achieving cost and material reduction. The study evaluates three commonly used materials—Steel 304, Aluminium 7075, and Titanium 6211—to determine how topology optimization affects the structural performance, cost, and weight of components before and after optimization. It was observed that topology optimization maximizes the weight reduction of materials, reducing manufacturing costs, most particularly when applied to large production volumes. For instance, after topology optimization, it may be realized that the cost per piece for Steel 304 almost nearly decreased to 50% of total cost and further decreased to 28% for 100 units on larger runs. This is primarily due to the 40% reduction in weight from 1.523 kg to 0.886 kg, which results in substantial savings. Regarding the specific case of Aluminium 7075 and Titanium 6211, the two replacements of alloys were quite significant both in weight and cost reduction, especially if upscale of quantity was considered one of the key drivers in reducing production costs. In terms of cost efficiency, additive manufacturing, when integrated with consolation and topology optimization, is still more costly compared to conventional high-volume manufacturing. It is mainly due to the cost involved in high direct manufacturing costs in AM from machines and materials as well as the post-processing needs to meet the dimensions mentioned in manufacturing drawings. However, it presents an intriguing option in the context of low volume production, focusing on maintaining low inventory in the organization and on demand fabrication in case a section of a part has failed.
  • Assuring quality of injection molded products by validating design and manufacturability with injection molding simulation
    (2019-12-16) Pekkarinen, Jenni
     Insinööritieteiden korkeakoulu | Master's thesis
    The purpose of this thesis is to assure quality of injection molded products by validating their design and manufacturability with injection molding simulation. Goal for this is to validate the product design already in its design phase and to recognize possible risks, in both product and mold designs, which could cause mold failure during injection molding. To gain confidence to validate design choices based on injection molding simulation, equivalency between simulation and real molding process are studied with one of ABB’s current product. For this study, the real molding parameters from production are used for simulation and cooling channels are constructed to imitate the real mold as close as possible. In addition, comparative studies with simplified cooling channels and with default process parameters are conducted to simulate the circumstances when product designer is designing a new product, mold construction and process parameters of which aren’t yet known. One additional study was done to see the behavior of polypropylene in a mold constructed for PC-ABS and to analyze the possibility to use polypropylene instead of PC-ABS in already existing mold. Another part of this thesis concerned the possibility to predict mold failure from the simulation results. This study was done by simulating one existing product case where inserts were noticed to have cracks after first tests in molding trials. The results show that simulation predicts more warping to the product than is seen in the real molding process. Reason for this unexpected high warpage was believed to be in the material data used. Studies with simplified cooling channels and process parameters showed quite consistent values and high differences weren’t seen when compared to simulation done with real process parameters. Polypropylene had slightly higher displacements than PC-ABS, but by adjusting the process parameters, it could be most likely used in the mold designed for PC-ABS. Simulation of the mold insert failing case showed some high pressure differences on the insert base, which were analyzed to be the cause for inserts’ cracking. High pressure differences resulted from the uneven filling pattern and gate locations. In order to decrease the risk for insert breaking, gate locations were moved, and changes were made to the product design to improve the melt flow pattern and to even the pressure differences. This study showed that by studying the filling pattern and pressure differences over the tool inserts, high risk areas can be identified even before mold construction.