Two-component injection moulding is a manufacturing process used to combine polymers with different properties within a single product. The process is often used to combine thermoplastics of ...different colours or to combine thermoplastic elastomers with thermoplastics to create hard and soft areas. In this study, a two-component injection moulding process is proposed for combining thermoplastics with thermoset rubbers. This poses technological challenges since rubbers require a heated mould (160–200
∘
C) for the rubber to vulcanise whereas thermoplastics need a relatively cold mould (20–100
∘
C) for the polymer to solidify. The mould used for this study is equipped with thermally separated mould cavities and allows to reverse the injection sequence of the two materials. It was found that the optimal sequence is to inject the thermoplastic first, followed by rubber, and that the mould temperature at the interface during the vulcanisation of the rubber is a critical process parameter. Too low mould temperatures at the interface result in long vulcanisation times and poor adhesion, whereas higher temperatures at the interface both decrease the vulcanisation time and increase the adhesion strength. However, when the temperature is too high, the adhesion strength decreases again due to gas bubbles at the interface released during the vulcanisation process.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Two-component (2k) injection moulding is an important process technique at the present state of technology, and it is growing rapidly in the field of precision micro moulding. Besides combining ...different material properties in the same product, two-component moulding can eliminate many assembly steps in the manufacturing process chain. One of the biggest technical challenges associated with 2k moulding is the unavailability of suitable material combinations which can meet the diverse requirement from both product and process point of views. When it comes to the point of micro application, the precise dimensional requirement and tolerance make the 2k moulding a technically challenging process. This paper presents an industrial case study of 2k micro moulding covering all the important issues like product design, material selection, moulding and functionality testing of the micro moulded 2k parts. An intensive search for suitable 2k materials is made and few combinations of plastic materials are presented in the paper which can be used for highly demanding application areas like hearing aids. By using these material combinations, a demonstrator 2k micro part has been fabricated. The moulding machine was a state-of-the-art 2k micro machine from DESMA. The fabricated micro part was a socket house integrated with a sealing ring for the receiver-in-canal hearing instrument. The test performed on the demonstrator showed the potential of the 2k moulding technology to be able to solve some of the existing problems associated with hearing instruments.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Two-component injection moulding is a commercially important manufacturing process and a key technology for combining different material properties in a single plastic product. It is also one of most ...industrially adaptive process chain for manufacturing so-called moulded interconnect devices (MIDs). Many fascinating applications of two-component or multi-component polymer parts are restricted due to the weak interfacial adhesion of the polymers. A thorough understanding of the factors that influence the bond strength of polymers is necessary for multi-component polymer processing. This paper investigates the effects of the process conditions and geometrical factors on the bond strength of two-component polymer parts and identifies the factors which can effectively control the adhesion between two polymers. The effects of environmental conditions on the bond strength are also investigated. Investigation shows that melt and mould temperatures are vital process parameters that influence the bond strength. Besides this, surface roughness of the first-shot part and environmental factors like moisture have profound influence on the bonding of the two materials. The selections of materials and environmental conditions were done based on the suitability of MID production, but the results could be useful for two-component polymer processing for a wide range of industrial applications. The results and discussion presented in this paper are only valid for the two-component plastic parts moulded by over moulding in cavity-transfer process.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
With standard microinjection moulding becoming more and more established in practical manufacturing, special variants are attracting increasing attention. Especially, the approaches on ...multi-component microinjection moulding are worth mentioning: As handling and assembly are difficult procedures especially in microtechnology, methods to reduce mounting efforts are of high economic importance. By merging of shaping and mounting procedures in one step, economic progress as well as new material combinations can be obtained. An interesting approach for the fabrication of metal (or in principal, ceramic) microcomponents is the combination of insert injection moulding and metal deposition by electroforming. First, an electrically conductive base plate is produced by injection moulding of conductively filled polymers. In a second injection moulding step, microstructures consisting of insulating plastics are mounted on these plates. The quasi-infinite conductivity gradient allows controlled electroplating starting at the base plate only so that defect-free metal microcomponents can be achieved. As a further variant of microinjection moulding, the development of the so-called MicroPIM process facilitates a large-scale series fabrication technology for metal and ceramic microcomponents. Combined with multi-component technology, an interesting new approach for micromanufacturing is obtained, i.e. the realisation of magnetic/non-magnetic or conductive/non-conductive material combinations by two-component MicroPIM. But, also the combination of different mechanical properties like hard/tough pairings is possible.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Moulded interconnect devices (MIDs) are plastic substrates with electrical infrastructure. The fabrication of MIDs is usually based on injection moulding, and different process chains may be ...identified from this starting point. The use of MIDs has been driven primarily by the automotive sector, but recently, the medical sector seems more and more interested. In particular, the possibility of miniaturisation of three-dimensional components with electrical infrastructure is attractive. The present paper describes possible manufacturing routes and challenges of miniaturised MIDs based on two-component injection moulding and subsequent metallisation. This technology promises cost effective and convergent manufacturing approaches for both macro- and microapplications. This paper presents the results of industrial MID production based on two-component injection moulding and discusses the important issues for MID production that can modulate the qualities of final MID. The results and discussion presented here can be a valuable user guide for mass production of moulded interconnect devices.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Today, microinjection moulding represents an established special variant among the different replication techniques strongly promoted by the growing market demand for microcomponents. Spearheading ...progress towards more sophisticated technologies, micro powder injection moulding offers a large scale fabrication process for metal/ceramic microparts. Minimal details in the range of 10 μm and replication accuracy down to ±0·3% (in special cases, ±0·1%) can be reached. With a twofold aim of reducing mounting costs and enabling the production of highly integrated devices two-component microinjection moulding is under development. Interesting examples are immovable or movable ceramic shaft wheel components.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Fabrication of steel molds is a major expense (time and cost) in ceramic injection molding research and development. 3D printed resin molds for fast prototyping are therefore highly attractive and ...have gained increasing attention. This paper reports strategies to use sacrificial molds 3D printed by fused deposition modeling (FDM) from PVA or digital light processing (DLP) from water soluble resin. Usage of sacrificial molds allows injection molding of complex geometries, which are not accessible for simple two-part molds. Ceramic heating elements in diverse geometries were injection molded using a composite feedstock containing MoSi2, Al2O3 and feldspar. More parts with various geometries were produced from Al2O3 feedstock. A comparison revealed that DLP printed molds are better suited for parts with very small structural features due to the higher resolution of the DLP process as compared to FDM. Finally, ceramic heaters were fabricated using two-component ceramic injection molding and successfully tested.
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•3D printed injection molds are faster and cheaper to produce than steel molds.•Sacrificial 3D printed injection molds allow complex part geometries including undercuts.•High quality sintered parts are made from FDM printed PVA molds.•Resolution of DLP printed resin molds is higher than FDM printed PVA molds.•Sacrificial molds enable two-component ceramic injection molding.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two-component (2K) injection molding of the combination of recycled polypropylene (rPP) and ethylene propylene diene monomer (EPDM) is very promising for automotive industry. Recently, the use of ...post-industrial wastes in the automotive industry became important in terms of reducing its environmental impacts and circular economy principles. In this study, the effect of processing parameters on the properties of rPP/EPDM deflector parts fabricated by means of a 2K injection molding process was investigated. Post-industrial waste PP was used in varying amounts (0%, 10% and 20% by weight) in rPP/EPDM parts. The properties of aged and unaged rPP/EPDM deflector parts were then compared. The effects of processing parameters on dimensional, mechanical, thermal, and morphological properties of rPP/EPDM parts were investigated by a coordinate measuring device (CMM), scanning electron microscope (SEM), tensile test, and differential scanning calorimetry (DSC) analysis. As a result of the CMM analysis, it was seen that the dimensional stability of the unaged parts was better than the aged parts. The adhesion between rPP and EPDM was found to be dependent on injection temperatures.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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