No / Ultrasonic technology provides a powerful and noninvasive method of in-process measurement during injection molding and extrusion. Changes in the velocity, attenuation and reflection coefficients of high frequency sound waves can be related to the state and conditions of the materials through which they propagate. The velocity of an ultrasonic wave changes with density and elastic moduli; this allows information on solidification and material properties to be collected during the molding cycle. The time of flight of the wave is a function of velocity and path length. This paper shows that it can be correlated with the residual wall thickness of polymer in the mold during gas assisted injection molding.

No / Injection moulding techniques have been miniaturised and refined to achieve micromoulding which aims to satisfy the need for mass production of low-cost micro- and nanoscale components. However, the microscale mould cavity features and extreme processing conditions which are inherent in the process can result in larger process variations than conventional injection moulding, with a corresponding increase in the probability of producing an unsatisfactory product. Accurate process diagnosis is required to ensure process reliability but integration of sensors onto the small and highly detailed mould units can be problematic and alternatives may need to be sought. Piezoelectric film ultrasonic transducers were integrated onto the extrusion barrel and mould insert of a micromoulding machine for real-time, non-destructive and non-intrusive process diagnosis with an ultrasonic pulse-echo technique. Polymer degradation owing to excessive heating at the extrusion barrel was successfully probed by measuring the ultrasonic velocities in the polymer at the mould insert. Filling incompleteness of the mould cavity was also sensitively detected by monitoring the ultrasonic energy variation transmitted into the part at different points along the melt flow length. The developed ultrasonic sensors and technique enable optimisation and in-process quality assurance of the moulded parts which ensures that maximum process efficiency can be achieved.

Formsprutning är en tillverkningsmetod somställer krav på produkters utformning. För att göra en lämplig ingötsplacering räcker inte alltid riktlinjer utan en produktspecifik analys kan vara nödvändig. Materialval kräver en tydlig kravspecifikation och kan med fördel göras i samråd med en materialexpert. Riktlinjer för Design for manufacturing and assembly inkluderar bland annat rekommendationer för formgivning. Detta kandidatarbete strävar efter att hjälpa produktutvecklare att tidigt i produktutvecklingsprocessen ta hänsyn till tillverkningsaspekter. Baserat på litteraturstudier, intervjuer och fallstudier har riktlinjer tagits fram för materialval, design for manufacturing and assembly och formgivning för formsprutning. Arbetet är avgränsat till att endast titta på formsprutningsbara termoplaster. Arbetet, som genomförts vid Linköpings universitet, är en del av projektet Säkra monteringsverktyg som resulterade i ett portabelt dödmansgrepp. Defallstudier som genomfördes inom projektetbehandlar värdering av koncept utifrån produktionsperspektiv, materialval och formsprutningsanalyser i programmet Moldflow. Arbetet resulterade i riktlinjer för applicering av metoden design for manufacturing and assembly, formsprutningsanpassning samt materialval. Fallstudien i Säkra monteringsverktyg utmynnade ien värdering av koncept utifrån produktionsaspekter, ett materialval baserat på projektets kravspecifikation och rekommendationer för produktens utformning med syfte att optimera dess tillverkning. En slutsats av arbetet är att produktionsanpassning av produktens utformning bör ske tidigt i utvecklingsprocessen. En annan slutsats är att besök i industrin, hos exempelvis ett formsprutningsföretag, leder till bättre förståelse av vilka krav som behöver uppfyllas för att en produkt ska vara möjlig att producera. Om simuleringsprogram för formsprutning finns bör det användas i kombination med riktlinjer för produktutformning. Ytterligare en slutsats som gjorts är att materialval underlättas genom tidig kontakt med materialleverantörer. Materialvalet baseras på kravspecifikationen och därför bör kraven tydliggöras och dess rimlighet kontrolleras innan materialvalet sker. / Injection molding is a manufacturing method that requires specific features to attain manufacturability. Gating suitability requires analysis and mere guidelines do not always provide the correct gate placement. Material selection requires a pronounced specification and is preferably supervised by an expert. Guidelines concerning design for manufacturing and assembly include, among other things, recommendations directly affecting the shape of the product. The aim for this bachelor thesis is to aid product developers and designers in taking manufacturing aspects into account early in the product development process. This is achieved by providing them with guidelines regarding material selection, injection molding, as well as design for manufacturing and assembly. The thesis is limited to thermoplastic materials suitable for injection molding and its results are based off thorough literature research, interviews and case studies. This bachelor thesis project, which is conducted at Linköping University,is a part of a project calledSafe manual assembly tools, and the resulting portable enabling device developed in Safe manual assembly toolsis used as case studies in this thesis. The case studies include: evaluation of concepts concerning manufacturability; material selection; and injection molding analysis through the software Moldflow. The thesis results in guidelines concerning design for manufacturing and assembly, injection molding and material selection. The case study is requited with concept selection suggestions, a selection of material that meets the specification of requirements stated in Safe manual assembly tools and design recommendations that aim to improve the manufacturability of the concept. This bachelor thesis concludes that design alterations striving to meet requirements for manufacturability should be made early in the devolpment process. Visiting the polymer-based product manufacturing industry offers better insight into which requirements that need to be fulfilled to make a product producible. Injection molding simulation software, if such is available, should be used in combination with design guidelines.The thesis also concludes that material selection is simplified through early contact with suppliers of material. Material selection is based off the specification of requirements and therefore requirements specified in the specification should be clarified and have their plausibility confirmed before the selection takes place.

To prevent damage to the cabin crew an optimal coffee- and teapot in a number of aspects in airline catering was developed, so called “SAS-kannan”. It was launched in 1980 and has been manufactured in over 300 000 copies, which has worn out the mold and it is in need of replacement. The mold is advanced and it will be expensive to manufacture a new one. August Lundh who is the manufacture of “SAS-kannan” today, want to develop a new product for serving drinks with a cost-effective manufacturing. It should involve the positive qualities on the “SAS-kannan” and be adapted to today's airline catering. The objective of the thesis was to develop an ergonomic and functional product for serving cold drinks with cost-effective production and the adaptation to today's storage trolleys on aircrafts. The research began with a comprehensive theoretical framework consisting of scientific articles and academic approved books. Interviews were made to complement the theoretical framework and primary data was collected. All the gathered information was examined in the next step to ensure the validity and reliability. A case study was conducted at August Lundh by a product development that was based on the examined information. To do more detailed tests 3Dprintings were created of each development. The result was a pitcher that is designed to enable an uncomplicated and ergonomic use. It is also adapted for efficient and stable storage in the ATLASboxes, easy filling of the beverage and washing. The pitcher holds 1.5 liters and is a perfect combination of the number of servings, refills of the pitcher and a low weight. The pitcher is made with injection molding and is made out of the Bisfenol A free plastic Tritan. The grip is designed to give the pitcher an ergonomic use for different sized hands and it is symmetrical to allow equal use of both left and right handed. The spout provides a controlled and even beam, and a drip free serving by cutting the beam properly. The spout is designed so that the pitcher only needs to be tilted 90 degrees from an upright position to be emptied. The lid is a separate part which is put on the pitcher with press-fit and it helps to control the beam during serving and to prevent spills in case of turbulence. The authors believe that the objective has been accomplished by a thorough theoretical framework and an empirical study through interviews and a case study. / För att förhindra skador på kabinpersonal utvecklades SAS-kannan som var en optimal kaffe- och tekanna i ett flertal aspekter inom flygcatering. Den lanserades på 1980-talet och har idag tillverkats i över 300 000 exemplar vilket har medfört att formverktyget blivit slitet och är i behov av att bytas ut. Det befintliga formverktyget är avancerat och det blir dyrt att tillverka ett nytt. August Lundh som idag tillverkar SAS-kannan vill därför utveckla en ny produkt för servering av dryck med en kostnadseffektiv tillverkning. Den ska kunna jämföras med SASkannans positiva egenskaper och vara anpassad för dagens flygcatering. Syftet med examensarbetet var att ta fram en ergonomisk och funktionell produkt för servering av kall dryck med kostnadseffektiv tillverkning samt anpassning till dagens förvaring i serveringsvagnar på flygplan. Forskningsprocessen påbörjades med en omfattande teoretisk referensram bestående av vetenskapliga artiklar och akademiskt godkända böcker. Intervjuer gjordes för att komplettera den teoretiska referensramen och primärdata samlades in. All insamlad information granskades i nästa steg för att säkerställa validiteten och reliabiliteten. En fallstudie utfördes hos August Lundh i form av en produktutveckling som var baserad på den granskade informationen. För att kunna göra utförligare tester skapades 3D-utskrifter av varje utveckling. Resultatet blev en kanna som är utformad för att möjliggöra en enkel och ergonomisk användning. Den är även anpassad för effektiv och stabil förvaring i ATLAS-lådor, enkel påfyllning av dryck samt rengöring. Då kannan rymmer 1,5 liter ger det en perfekt kombination av antal serveringar, påfyllningar av kannan samt en låg vikt. Kannan är formsprutad och är tillverkad i den Bisfenol A-fria plasten Tritan. Greppet är utformat för att ge kannan en ergonomisk användning för olika stora händer och är symmetrisk för att möjliggöra lika användning av både höger- och vänsterhänta. Pipen ger en kontrollerad och jämn stråle samt en droppfri servering genom att skära av strålen ordentligt. Pipen är utformad så att kannan endast behöver vinklas 90 grader från upprätt läge för att kunna tömmas. Locket är en separat del som sätts på kannan med presspassning och hjälper till att kontrollera strålen under servering samt förhindra spill vid eventuell turbulens. Författarna anser att syftet har uppfyllts genom att en grundlig teoretisk referensram och en empirisk studie genom intervjuer och en fallstudie utfördes.

Procédé de moulage par injection de poudres est constitué de quatre étapes principales: la préparation des matières premières, moulage par injection, le déliantage et le frittage. Cette thèse présente les recherches sur deux aspects principaux: la micro-injection et frittage par micro -ondes. Les contributions principaux peuvent être conclues dans les quatre aspects suivants: Modification et complément de l'algorithme précédent pour la simulation du procédé de moulage par injection; L'évaluation et la mise en œuvre de l'effet de tension de surface en simulation pour micro-injection; Micro-ondes expériences de frittage de compacts basés sur l'acier inoxydable 17-4PH; Réalisation de la simulation de frittage à micro-ondes avec couplage de la multi-physique, y compris le chauffage à micro-ondes classique, le transfert de chaleur, et le supplément de modèle pour la densification de frittage de la poudre compacté / Powder Injection molding process consists off our main stages: feedstock preparation, injection molding, debinding and sintering. The thesis presents the research on two main aspects: micro injectionmolding and microwave sintering. The main contributions can be concluded in thefollowing four aspects: Modification and supplement of previous algorithm for the simulation ofinjection molding process; Evaluation and implementation of surface tension effect in simulation for micro injection; Microwave sintering experiments of compacts based on 17-4PH stainles ssteel; Realization of the microwave sintering simulation with the coupling of multi-physics,including the classic microwave heating, heat transfer, and the supplement of model for sintering densification of powder impacts

O processo de moldagem de pós injeção é utilizado para a fabricação de peças de geometrias complexas e com alto volume de produção. Em aplicações ortodônticas e médicas, nas quais são requeridas elevadas durezas e resistências à corrosão, o aço inoxidável 17-4 PH é utilizado aplicando-se aquela técnica de conformação. A atmosfera de sinterização é responsável pelo controle das reações químicas que ocorrem durante a densificação do material e são fundamentais para a qualidade final do produto. O objetivo deste trabalho foi avaliar a influência da atmosfera de sinterização na dureza e resistência à corrosão deste tipo de aço. A remoção dos ligantes primários foi realizada por meio de extração química utilizando-se um solvente com menor impacto ambiental, que se mostrou adequado a tal fim. A extração térmica posterior dos ligantes foi realizada pelo aquecimento nas temperaturas de 250°C e 450°C sendo, posteriormente, a temperatura elevada a 900°C, para o início da sinterização. Utilizou-se atmosferas de Nitrogênio, Vácuo e Hidrogênio, com temperaturas de sinterização de 1250°C e 1330°, com tempos de patamares de 30 e 60 minutos. Verificou-se que as densidades atingidas nas atmosferas de Hidrogênio e Vácuo são semelhantes e se adequaram às especificações requeridas pela norma, enquanto a atmosfera de Nitrogênio resultou em características inferiores. As durezas e as resistências à corrosão obtidas com o uso das atmosferas de Hidrogênio e Vácuo foram também superiores as das amostras sinterizadas em atmosfera de Nitrogênio. / The powder injection molding process is used to manufacture parts with complex shapes, with high production demand. In orthodontic and medical applications, in which high hardness and corrosion resistance are required, 17-4 PH stainless steel is used by applying this forming technique. The sintering atmosphere is responsible for controlling the chemical reactions that occur during material densification and is critical to the ultimate product quality. This research study aims at evaluating the influence of the sintering atmosphere on the hardness and corrosion resistance of this type of steel. The removal of the primary binder was carried out by chemical extraction applying a solvent with less environmental impact, which has proved to be suitable for this purpose. The subsequent binder thermal extraction was held by heating at temperatures of 250°C and 450°C and, therefore, at temperature of 900°C, to initiate sintering. Nitrogen, vacuum and hydrogen atmospheres were used with sintering temperatures at 1250°C and 1330°, with 30 and 60 minute-step time. It was verified that the densities achieved in hydrogen and vacuum atmospheres are similar and suitable by the regulations, whereas the nitrogen atmosphere resulted in lower performance. The hardness and corrosion resistance obtained with the use of hydrogen and vacuum atmospheres were also higher than those obtained for samples sintered in the nitrogen atmosphere.

Process-induced Long-term Deformation Behavior of Injection Molded Semicrystalline Thermoplastics Injection molding is a very complex process because the polymer experiences a complex thermorheological history during molding that influences the molecular orientation, residual stresses, frozen-in free volume and crystallinity inside the part. These generally govern the final part properties. Therefore it is highly desirable to anticipate the effect of process parameters on the resulting microstructure and mechanical properties of the finished part in the long run. In the case of a semicrystalline thermoplastic part, the problem in understanding the deformation behavior arises from its two-phase structure and a tendency exists to concentrate primarily on the effect of the crystalline phase on the deformation behavior, while the contribution of the amorphous phase is less investigated. In this work, the influence of the processing parameters on the deformation behavior of injection molded semicrystalline thermoplastic parts, viz., syndiotactic Polystyrene (sPS) and Polybutylene terepthalate (PBT), has been monitored through creep. The resulting internal structures due to processing have been determined and the deformation behavior has been analyzed. It has been observed that only the rate of cooling shows a remarkable effect on the long-term viscoelastic behavior of an injection molded semicrystalline thermoplastic part as it influences not only the crystalline, but also the free volume fraction, whereas the different states of frozen-in orientations and pressure-induced densification have only a negligible effect. Besides, physical aging also plays an important role in the deformation behavior of the injection moldings which was manifested with the decrease in the tendency to creep. Therefore, it was suggested that the cooling rate during injection molding and the aging time can significantly affect the long-term deformation behavior of the injection molded semicrystalline thermoplastics. The results also showed that when no significant effect is observed in terms of short-term mechanical properties by changing the processing conditions, but while considering the long-term behavior they show a significant effect.

Werkstoffe auf Basis duroplastischer Harze besitzen exzellente Gebrauchseigenschaften für viele Bereiche des industriellen Einsatzes. Vor allem durch die Spritzgießverarbeitung rieselfähiger duroplastischer Formmassen entsteht ein hohes Substitutionspotential gegenüber Bauteilen aus Metallen oder Hochleistungsthermoplasten. Jedoch führen bestehende Erkenntnisdefizite im Prozessverständnis zu Ressentiments hinsichtlich des Einsatzes duroplastischer Werkstoffe. Ziel der Untersuchungen dieser Arbeit war die Ermittlung und Analyse der prozessinduzierten Werkstoffstruktur von spritzgegossenen technischen Phenolharzformteilen. Dabei wurden zum einen das Füllen der Werkzeugkavität und die sich ausbildende Faserorientierung untersucht und zum anderen die sich während des Temperns verändernde chemische Struktur. Anhand von Platten- sowie Zugprüfkörpern wurden sowohl beim Spritzgießen als auch beim Tempern Parametervariationen durchgeführt und die jeweils resultierende Werkstoffstruktur sowie deren Einfluss auf die Formteileigenschaften analysiert. Die Ergebnisse zeigen, dass die Strömungsverhältnisse während der Werkzeugfüllung stark von den Prozessparametern und der Werkstoffzusammensetzung abhängig sind. Dadurch wird auch die Faserorientierung beeinflusst, sodass im Formteil lokal und richtungsabhängig stark unterschiedliche Eigenschaften entstehen können. Darüber hinaus konnte anhand einer alternativen Tempermethode geklärt werden, warum es beim Tempern zu einem Abfall der mechanischen Eigenschaften kommt und eine Möglichkeit zur Vermeidung gegeben werden. / Because of their excellent properties, thermosets can be applied in a bright range of industrial applications. Especially thermoset molding compounds can be processed highly effective by injection molding, which enables them to substitute metals or high performance thermoplastics. But there is a deficit in process understanding, which limits the industrial application. The objective of this work is the investigation and analysis of the process induced material structure of injection molded technical phenolic components. Therefor the filling of the cavity with the resulting fiber orientation and the chemical processes during post-curing were examined. A parameter variation with injection molded plate and tensile specimens were done and the resulting material structure and the effect on the component properties were analyzed. The results show a big influence of the process parameter and the material on the flow condition during the filling of the cavity. Thereby also the fiber orientation is affected. This leads to process-depending local and direction-depending properties. In addition, this work shows an alternative method for post-curing to avoid the decrease of mechanical properties.

O processo de moldagem de pós injeção é utilizado para a fabricação de peças de geometrias complexas e com alto volume de produção. Em aplicações ortodônticas e médicas, nas quais são requeridas elevadas durezas e resistências à corrosão, o aço inoxidável 17-4 PH é utilizado aplicando-se aquela técnica de conformação. A atmosfera de sinterização é responsável pelo controle das reações químicas que ocorrem durante a densificação do material e são fundamentais para a qualidade final do produto. O objetivo deste trabalho foi avaliar a influência da atmosfera de sinterização na dureza e resistência à corrosão deste tipo de aço. A remoção dos ligantes primários foi realizada por meio de extração química utilizando-se um solvente com menor impacto ambiental, que se mostrou adequado a tal fim. A extração térmica posterior dos ligantes foi realizada pelo aquecimento nas temperaturas de 250°C e 450°C sendo, posteriormente, a temperatura elevada a 900°C, para o início da sinterização. Utilizou-se atmosferas de Nitrogênio, Vácuo e Hidrogênio, com temperaturas de sinterização de 1250°C e 1330°, com tempos de patamares de 30 e 60 minutos. Verificou-se que as densidades atingidas nas atmosferas de Hidrogênio e Vácuo são semelhantes e se adequaram às especificações requeridas pela norma, enquanto a atmosfera de Nitrogênio resultou em características inferiores. As durezas e as resistências à corrosão obtidas com o uso das atmosferas de Hidrogênio e Vácuo foram também superiores as das amostras sinterizadas em atmosfera de Nitrogênio. / The powder injection molding process is used to manufacture parts with complex shapes, with high production demand. In orthodontic and medical applications, in which high hardness and corrosion resistance are required, 17-4 PH stainless steel is used by applying this forming technique. The sintering atmosphere is responsible for controlling the chemical reactions that occur during material densification and is critical to the ultimate product quality. This research study aims at evaluating the influence of the sintering atmosphere on the hardness and corrosion resistance of this type of steel. The removal of the primary binder was carried out by chemical extraction applying a solvent with less environmental impact, which has proved to be suitable for this purpose. The subsequent binder thermal extraction was held by heating at temperatures of 250°C and 450°C and, therefore, at temperature of 900°C, to initiate sintering. Nitrogen, vacuum and hydrogen atmospheres were used with sintering temperatures at 1250°C and 1330°, with 30 and 60 minute-step time. It was verified that the densities achieved in hydrogen and vacuum atmospheres are similar and suitable by the regulations, whereas the nitrogen atmosphere resulted in lower performance. The hardness and corrosion resistance obtained with the use of hydrogen and vacuum atmospheres were also higher than those obtained for samples sintered in the nitrogen atmosphere.

Made available in DSpace on 2016-06-02T19:10:22Z (GMT). No. of bitstreams: 1 6015.pdf: 4561575 bytes, checksum: 252a378ed3b63f6b097f991565a256f1 (MD5) Previous issue date: 2014-04-04 / Financiadora de Estudos e Projetos / This study aimed at evaluating the potential of application of cellulose nanocrystals as reinforcing elements of biodegradable polymeric matrices, in the films and injection molded pieces applications. Two polymeric matrices with different properties were used, namely: poly(butylene adipate-co-terephthalate), PBAT, and poly(lactic acid), PLA. For the extraction of cellulose nanocrystals (NCC), two sources were selected: microcrystalline cellulose (CMC) and balsa wood . Due to the high polarity of cellulose nanocrystals, different approaches of surface chemical modifications of these particles were tested, in order to ensure their good dispersion when added to polymeric matrices of lower polarity. They were: a) chemical modification with two types of isocyanates, an aliphatic one (octadecyl isocyanate) and an aromatic one (phenylbutyl isocyanate); b) grafting of poly (butylene glutarate) using the in situ polymerization technique; c) silanization treatment; and d) grafting of poly(acrylic acid) through click chemistry technique. Modified and unmodified NCCs were processed with PBAT and PLA by casting or melt extrusion processing techniques. In general, the chemical modification of NCC surface increased their thermal resistance, decreased their polarity and improved their dispersion into PLA and PBAT matrices. Some of these treatments, as well as the processing conditions enabled an increase in the overall mechanical properties of the polymers. Thus, the characterization of the nanocomposites showed that NCC addition increased the elastic modulus of the matrix and retained its higher stiffness even under relatively high temperatures. Higher NCC contents led to larger increases in the stiffness of the ensuing composites. The water vapor permeability of PBAT was also reduced with the introduction of NCC. This work points out several potential good perspectives for the use of celulose nanocrystals as reinforcing elements of polymeric matrices. It showed also that it is possible to obtain significant improvements in the polymer properties using the same processing techniques as those used at industrial scale, such as melt extrusion and injection molding. / O presente estudo de doutorado teve como objetivo avaliar o potencial de aplicação de nanocristais de celulose como reforço em matrizes poliméricas biodegradáveis, em aplicações de filmes ou em peças moldadas por injeção. Duas matrizes poliméricas de diferentes propriedades foram utilizadas para estudo nessas aplicações, sendo elas: poli(butileno adipato-co-tereftalato), PBAT, e poli(ácido láctico), PLA. Foram também selecionadas duas fontes para extração dos nanocristais de celulose (NCC): a celulose microcristalina (CMC) e a madeira balsa. Devido ao caráter altamente polar dos nanocristais de celulose diferentes rotas de modificações químicas superficiais dessas partículas foram testadas, visando garantir a boa dispersão dos mesmos quando adicionados às matrizes poliméricas de menor polaridade. Foram elas: a) modificação química com dois tipos de isocianatos, sendo um de cadeia alifática (octadecil isocianato) e outro de cadeia aromática (fenilbutil isocianato); b) enxertia do poli(butileno glutarato) através da técnica de polimerização in situ; c) tratamento de silanização com - metacriloxi-propil-trimetoxi-silano; d) enxertia de poli(ácido acrílico) através da técnica de click chemistry. NCC modificados e não modificados foram processados com PBAT ou PLA através de mistura com o polímero em solução (casting) ou no estado fundido (extrusão ou homogeneizador de alta rotação do tipo Drais). De modo geral, modificações químicas superficiais dos NCC aumentaram a estabilidade térmica dos mesmos, diminuíram sua polaridade e melhoraram a dispersão dos NCC nas matrizes de PBAT ou PLA. Isso fez com que incrementos ainda maiores nas propriedades desses polímeros pudessem ser alcançados, dependendo do tipo de modificação e do processo de mistura utilizados. A caracterização dos nanocompósitos obtidos mostrou que a adição de NCC elevou o módulo elástico das matrizes e conservou sua maior rigidez mesmo em temperaturas relativamente elevadas, sendo que maiores teores de NCC levaram a maiores aumentos na rigidez. A permeabilidade a vapor de água do PBAT também foi reduzida com a introdução dos NCC e não foi alterada no caso do PLA. Os resultados desse trabalho apontaram boas perspectivas no uso dos nanocristais de celulose como reforços de matrizes poliméricas. Também mostraram que é possível obter melhorias nas propriedades de polímeros mesmo através da utilização de processos de maior reprodutibilidade em escala industrial, como extrusão e injeção.