Aminul Islam

Two-component microinjection moulding for MID fabrication

Abstract 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.

Advancements on the simulation of the micro injection moulding process

Process simulations are applied in micro injection molding with the same purpose as in conventional injection molding: aiming at optimization and support of the design of mold, inserts, plastic products, and the process itself. Available software packages are however not well suited for micro injection molding, because they are developed for macro plastic parts and they are therefore limited in the capability of modeling the polymer flow in micro cavities properly. However, new opportunities for improved accuracy have opened up due to current developments of the simulation technology. Hence, new strategies and aspects for comprehensive simulation models which provide more precise results for micro injection molding are discussed. Modeling and meshing recommendations are presented, leading to a multi-scale mesh of all relevant units in the injection molding process. The implementation of the process boundary conditions is described, being followed by results illustrating their importance on the simulation output. Finally, the influence of the cooling simulation settings is analyzed.

The shrinkage behavior and surface topographical investigation for micro metal injection molding

Metal injection molding (MIM) is a near net shape manufacturing technology that can produce highly complex and dimensionally stable parts for high end engineering applications. Despite the recent growth and industrial interest, micro metal molding is yet to be the field of extensive research especially when it is compared with micro molding of thermoplastics. The current paper presents a thorough investigation on the process of metal injection molding where it systematically characterizes the effects of important process conditions on the shrinkage and surface quality of molded parts with micro features. Effects of geometrical factors like feature dimensions and distance from the gate on the replication quality are studied. The influence of process conditions on the achievable roughness for the final metal parts is discussed based on the experimental findings. The test geometry is characterized by 2½D surface structures containing thin ribs of different aspect ratios and thicknesses in the sub-mm dimensio...

A comparative study of metal and ceramic injection moulding for precision applications

DTU Orbit (10/12/2018) A comparative study of metal and ceramic injection moulding for precision applications Powder injection moulding (PIM) process is an attractive process as it combines the possibilities of net-shape and largescale production with wide range of material varieties. This article presents a comparative study of two branches of PIM processes with the focus on precision application. The two branches of PIM metal injection moulding (MIM) and ceramic injection moulding (CIM) have been developed in parallel. Both processes are in a stage now where they can offer exciting possibilities for mass production of extremely precise and complex net shape products. For some applications, PIM process presents a dilemma for choosing between MIM and CIMas both the material classes can offer specific advantages and the process steps are identical. So a comparative study about the process capabilities between CIM and MIM will be useful for thorough understanding of the processes and to select the right material and process for the right application.With this motivation, the current paper systematically characterizes the PIM and CIM process and presents the process capabilities in terms of part shrinkage, surface replication, tolerance capability and morphological fidelity.

Validation of precision powder injection molding process simulations using a spiral test geometry

Like in many other areas of engineering, process simulations find application in precision injection molding to assist and optimize the quality and design of precise products and the molding process. Injection molding comprises mainly the manufacturing of plastic components. However, the variant of precision powder injection molding for the production of metallic and ceramic micro parts raises more and more interest though. Consequently, in the entire field the demand for simulation tools increases constantly, too. The present work reports the material characterization of feedstocks which are used for powder injection molding. This characterization includes measurements of rheological, thermal, and pvT behavior of the powder-binder-mixes. The acquired material data was used to generate new material models for the database of the commercially available Autodesk Moldflow® simulation software. The necessary data and the implementation procedure of the new material models are outlined. In order to validate th...

Influence of Process Temperatures on Blister Creation in Micro Film Insert Molding of a Dual Layer Membrane

In this work the suitability of a dual layer membrane, consisting of a non-woven Polypropylene (PP) support and a membrane layer made out of Polyethylene Terephthalate (PET) for Micro Film Insert Molding (μFIM) was investigated. The emergence of blisters at the surface of the PET-membrane layer was observed for some combinations of the process parameters used in this investigation. Since these blisters are not only an optical issue but can also deteriorate the functionality of the membrane, a blister free overmoulding of the membrane is required. In particular the mold and the barrel temperature were found to influence this blister creation. The influence of these two parameters on the amount of blisters and the blister height, characterized by the areal surface topography parameters peak material portion (Smr1) and reduced peak height (Spk), is presented in this paper.