Optimization of twin screw melt mixer setup process parameters for better blending of polymers and polymer composites for FDM applications

Abstract

In contrast to traditional method of mixing polymers and polymer composites in melt mixer setup, this paper is aimed to present the mixing in twin-screw internal melt mixer setup operated with optimized parameters leads to significant improvements viz., low power consumption, low mixing duration, effective mixing process. Certainly, these blended compounds are best suitable to use in fused deposition modelling (FDM) applications. The response surface method (RSM) optimization has been adopted for optimization of a twin-screw internal melt mixer process parameters. The influence of process parameters on response parameters has been obtained through analysis of variance (ANOVA) and 3D response analysis. Further, the raw polylactic acid (PLA) and PLA with reinforcement (bamboo cane fibre) have been compared for the rheological properties. The optimal parameter setting of screw speed 86 rpm, 3 wt% fibre loading and 6 wt% polyethylene glycol (PEG) loading is obtained through RSM. Subsequently, the process parameters screw speed, fibre loading and polyethylene glycol (PEG) loading have been observed as key parameters to significantly affect the response parameter. Against pure PLA, the best mixing process is evident through the enhanced rheological properties of PLA composites viz., flowrate of 4.40 × 10−2 cm3sec−1, shear rate of 51.19 s−1 and viscosity of 3.88 × 10−3 N-sec.m−2. The optimal process parameter setting of twin-screw internal melt mixer presented in this study would yield concrete homogenous blended compound with promising rheological properties to be useful for small scale vendors and additive manufacturing applications as well.

Keywords

• Polylactic acid (PLA)
• Twin screw melt mixer
• Bamboo-cane fibres (BCFs)
• Melt-flow index (MFI)
• Mixture blending time (MBT)
• Process parameters and ANOVA