Multimaterialprodukter og levetid i ulike miljø

A major trend internationally in design of lightweight structures in many high-performance products is a transition away from mono material solutions. Instead one tries to achieve optimal sustainable solutions by combining the best properties of different materials. This integration is often done directly in the production process (production integrated assembly), allowing integration of features and functionalities without a following assembly step. The main goal with this project (MuLUM) was to study some of the technological challenges faced in development of new multi-material-based solutions and components, particularly for use in various aggressive environments. The competence developed has been used to develop into new products from ideas the industrial partners had at the start of the project. An important R & D activity has been associated with the challenges faced when joining different component parts made in dissimilar materials. The joining methods that we have focused on have been mechanical fastening and cases where two materials are integrated in the actual manufacturing process. In this last situation we have studied cases where metal parts are integrated into a plastic product in the actual injection moulding process, or cases where different plastic materials with very different properties are combined using a so called two component injection moulding process. In the first part of the project the focus was on the technological challenges in material properties, production process and design solutions when we wanted to replace environmental O-ring seals whose function is to keep mud and dirt out, with an integrated injection moulded solution. In this solution a soft material with rubber properties and a hard fibre reinforced component are moulded together in the same production process. This work has resulted in a new product that was put into series production and introduced to the market in 2016. The technology has been developed further in another Research Council-supported IPN project. As a result of the work initiated in MuLUM and continued in the new project, several new coupling products have been developed that have either been or will be introduced to the market in the next few years. Mono-material products are often mounted (joined) with products in other materials. Differences in material properties (mechanical, thermal, chemical compatibility, etc.) lead to design challenges. The partner companies ISIFLO and Kongsberg Automotive produce coupling systems for water and gas distribution and for use in brake systems for the Commercial Vehicle segment respectively. Many of these couplings have a so-called push-in solution. That is, water or air pipes are fastened only by being pushed into the coupling without any further clamping through a threaded screw solution. For gripping the pipes, the couplings have an internal clamping ring machined from brass or moulded in plastics, or in moulded plastics with an embedded metal ring. Pipes are manufactured in different plastic materials, but even for pipes produced in the same material, the hardness and surface roughness vary. With some pipes there is a problem that the clamping ring do not grip well onto/into the pipe so that the pipe can be pulled out again. It is crucial for the quality of the coupling solution that this does not happen. In the project, we have worked methodically to obtain a thorough understanding of the influence various parameters characterising the materials involved have on the functional properties. In this work, we have combined in-house developed experimental setups with numerical modelling in order to obtain an understanding of what happens mechanically when a clamping ring "grabs" onto a plastic pipe when the pipe is being pulled out. This understanding is important in order to develop new and improved solutions for push-in couplings. Although we want to bring new solutions to the market, they must be able to be joined with old infrastructure solutions that is in use. So even though the push-in solution has been developed, couplings still must be able to be mounted with existing solutions with threaded connections. Mechanically, threading is a challenge with composite couplings. Several multi-material solutions have been studied to strengthen the threaded area of the couplings and we have developed a new solution that have been put into production. MuLUM has resulted in new products and solutions which have been launched in the market. In addition, we have developed several new product prototypes with new and / or improved properties which the companies will continue to develop into commercial products. All new products need an internal and external approval that takes some time before they can be launched. It is expected that most of these prototypes will in commercial production within the next few years.

Fokuset i prosjektet har vært knytet til utvikling av nye produkter og løsninger i partnerbedriftenes produktprogram. I tillegg til nye prototyper og produksjonsløsninger, har prosjektet bidratt til en betydelig kompetanseheving hos partnerne. Dette er spesielt knyttet til sprøytestøping (prosessforståelse og design av formverktøy), samt multimaterial produktdesign. De teknologiske problemene adressert er generelle og resultatene frembragt er av interesse for mange norske produsenter av plastprodukter. Den viktigste kompetansespredningen vil instituttpartnerne stå for, ved å ta kompetansen i bruk i framtidige prosjekter med andre norske bedrifter med produkter inn mot helt andre markeder. Slike samarbeidsprosjekter er svært viktige for at norsk bedrifter skal klare å realisere sine ambisiøse mål og drive lønnsom produksjon i Norge, nødvendig for å kunne overleve i tøff internasjonal konkurranse.

Det er en trend internasjonalt innen bærekraftig design av lettvektskonstruksjoner at man forsøker man å få til optimale løsninger ved å kombinere de beste egenskapene fra ulike materialer. Dette ønsker man å gjøre integrert i selve produksjonsprosessen (produksjonsintegrert montasje). På den måten kan man integrere egenskaper og funksjonalitet uten et etterfølgende monteringstrinn. Denne utviklingen finner partnerbedriftene interessant og vil forholde seg til. Hovedidéen med dette prosjektet er å studere de teknologiske utfordringene man står overfor i utvikling av nye multimaterialbaserte løsninger og komponenter, spesielt for bruk i ulike aggressive miljø, for å kunne realisere konkrete nye produktidéer. De fleste aktivitetene i dette prosjektet vil være relatert til integrasjon av metalldeler i et plastkomposittprodukt i en sprøytestøpeprosess, eller integrasjon av pakninger i produkter gjennom påstøp i en to-komponent sprøytestøpeprosess for å unngå ettermontering av pakninger. En annen utfordring er at selv om en del av et produkt er i en monomaterialløsning, så monteres (sammenføyes) de ofte med produkter i andre materialer. På grunn av forskjeller i materialegenskaper (mekaniske, termiske, kjemisk kompatibilitet etc) kan dette føre til designutfordringer. Prosjektet vil adressere dette. Et fellestrekk med produktene vi fokuserer på er at de i bruk stort sett står i et aggressivt miljø med varierende grad av vannkontakt. Det å være sikker på levetid, at egenskaper ikke forringes, er et viktig aspekt som vi må adressere for å kunne klare å få nye produkter og løsninger akseptert i et marked. Hovedmålet med FoU-aktivitetene er: (i) Utvikle metodikk for multimaterialbasert produktutvikling, dvs optimale valg av materialer, designløsninger og produksjonsprosesser og (ii) etablere forståelse for mekanismer for aldring/degradering av involverte materialer for aktuelle driftsmiljøer og driftsbetingelser.