The finite element analysis of melt flow behaviour in micro-injection moulding

Abstract

Micro-injection moulding as a replication method is one of the key technologies for micromanufacture. The understanding of process constraints for a selected production route is essential both at the design stage and during mass production. In this research, an existing finite element analysis system is used to verify the effects of four process parameters: the melt and mould temperatures, injection speed, and part thickness. Special attention is paid to the melt flow sensitivity when filling microchannels, particularly the factors affecting the shear rate, pressure, and temperature. In particular, the simulation model was used to investigate the flow behaviour of two polymer materials, polypropylene and acrylonitrile butadiene styrene, by varying the process parameters. Then, the results of this investigation were compared with those reported in an experimental study. Conclusions are made about the accuracy and sensitivity of the proposed simulation model.

Analysis for microstructure of micro-cantilevers arrays in micro-injection molding by using numerical simulations

“…The results showed a three-dimensional (3D) analysis based on the Navier-Stokes flow model can simulate the flow behavior in micro structures accurately comparing to the findings of previous studies [1]. It was observed that the micro component was completely filled under S2, S3 and S4 conditions.…”

“…the Cross and Williams-Landel-Ferry (WLF) models [1]. The Cross viscosity model, with the WLF temperature and pressure dependence factor, is a mathematical expression that describes the shear thinning behaviour of polymers and is widely used for numerical simulations.…”

“…Griffiths et al [1] studied the flow behavior of polymer melts in micro cavities by Moldflow Plastics Insight software and then validated against the experimental results of the study reported in reference [3]. They used two FEA models i.e.…”

Influence of Injection and Cavity Pressure on the Demoulding Force in Micro-Injection Moulding

“…To maintain T at a given level is critical for achieving the targeted effect by the applied pressure in /x-IM. In particular, an increase of melt temperature (Tb) results in a better filling and replication of microfeatures, while the use of the correct mould temperature (T^ can prevent early solidification [18][19][20]. Pontes and Pouzada designed an instmmented mould to assess the effects of the processing variables on F^.…”

Prototype tooling for producing small series of polymer microparts

“…There is a rich repository of polymer processing knowledge for injection moulding (IM), but due to scale effects such know-how cannot be employed directly in m-IM [7]. With the downscaling of part sizes, existing tool and part designs and polymer processing methods should be applied cautiously in m-IM, and some proven designs and processing strategies at the macro scale should be carefully reconsidered taking into account the scale effects [8]. In recent years researchers have focused their attention predominantly on the filling stage of the process, and have investigated the following main factors: melt temperature (T b ), mould temperature (T m ), injection speed (V i ), and injection pressure (P i ) [5,[9][10][11].…”