Process parameter effects on dimensional accuracy of a hot embossing process for polymer-based micro-fluidic device manufacturing

Abstract

The embossing of polymeric materials is widely used for manufacturing of micro-parts. The thermoplastic amorphous polymers are always selected to get microcomponents. The paper consists to characterise the thermal mechanical properties of three amorphous polymers: polystyrene (PS), poly(methyl methacrylate) (PMMA) and polycarbonate (PC). A set of experiments such as differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) have been carried out with PS, PMMA and PC. The thermoplastic polymers' behaviours have been characterised above their glass transition temperature. Then, flexible microfluidic devices have been manufactured with the polymers by hot embossing process. The surface topography of mould die cavity insert and the micro-fluidic devices have been observed and analysed by a 3D optical microscopy viewing and measurement system in order to compare the replication accuracy for polymeric replicas. The surface roughness of the microfluidic devices has been measured to characterise the effect of the compression load and temperature in the hot embossing process. The paper is mainly concentrated on the effect of the process parameters with different amorphous thermoplastic polymers to achieve the process optimization. The results concerning the micro-and nano-scale cavities filling provide information on the reliability about the facilities to replicate complex surface topographies. In this paper, the flow behaviour of polymer during forming process thus process parameters would be investigated. The mould instrumented with micro-structured patterns will be presented. The relationship between embossing conditions and parts quality will be established.

Influence of elastic-viscoplastic behaviour on the filling efficiency of amorphous thermoplastic polymer during the micro hot embossing process

“…More explanations were added in the second paragraph of Section 5.2, in the revised version of the manuscript. 5. Fig.…”

“…They combined photolithography and electroplating to form metal patterns with silicon and glass wafers as the mould. Cheng et al [5] successfully employed hot embossing with an innovative injection-moulding press and elastomeric mould to manufacture microfluidic systems of PMMA slightly above its .…”

Replication of microchannel structures in WC–Co feedstock using elastomeric replica moulds by hot embossing process

“…Most studies in this field have been focused on thermoplastics [44][45][46] because of their extensive usage in various applications; however, there are few reports that describe the details and challenges of powder hot embossing. Recently, Fu et al [47] investigated the manufacturing of 316L stainless steel cylindrical microstructure arrays using a silicon mould insert obtained by the hot embossing process.…”

Nonuniform Heating Method for Hot Embossing of Polymers with Multiscale Microstructures

“…The replicated pattern quality of the hot embossed part is significantly influenced by the process parameters, such as embossing pressure, embossing temperature, and holding time [ 27 , 28 , 29 , 30 , 31 ]. Furthermore, the effects of the geometric structures and size of the mold cavity on the hot embossing process are critical issues that need to be addressed, because the polymer replication ratio and filling height of the hot embossed product share a complicated nonlinear relationship with cavity size and density [ 32 , 33 , 34 , 35 ]. A nonuniform filling phenomenon is observed when a single embossing master mold contains multiple, nonuniform feature geometries.…”