Experimental Investigation on AFF of FDM Printed Pattern for Extrusion Die Insert

Abstract

Fused filament fabrication (FFF)/fused deposition modeling (FDM) is now a popular production process among the material extrusion family of additively manufactured (AM) processes due to its cost. Alike all AM methods in FDM, and the digital model is converted into a real-time product by depositing successive layers of material. Due to layer addition, the surface of these 3D printed components has poor quality. These surface defects are commonly known as stair casings/stepping effects. Three dimensional printed parts need to be finished before using them as patterns or any other application. Extrusion-based manufacturing is a mass production process for continuous products out of polymers and metals. High customization needs and modular design have led to the development of die inserts. FDM can be used for developing patterns for die inserts. The abrasive flow machining (AFM) could be an exceptional option for surface finishing these FDM printed parts before using them as patterns for developing extrusion die inserts. However, finishing 3D printed parts, particularly those with complex passages, remains a challenge. The objective of this research work aims to carry out experimentations on abrasive flow finishing (AFF) to finish an extrusion die insert pattern fabricated by the FDM process. The AFM media concentration, i.e., percentage of abrasive particles concentration, percentage of liquid synthesizer, and abrasive particles mesh size levels, were selected for better surface quality improvement of the FDM printed circular in-line die insert pattern. The process parameters, i.e., the percentage of abrasive particles concentration, abrasive particles mesh size, FDM part's layer thickness, and AFM finishing time, were identified for better surface improvement of internal passage of extrusion die insert pattern. Optimum parameters obtained in the rheological study of viscosity of cornstarch-based media are 66% abrasive particles concentration, and 220 abrasive particles mesh size. The maximum surface finish (ΔRa) observed is 2.2 µm with 90.40% of improvement by the process.