Session: 02-01-03: 7th Annual Conference-Wide Symposium on Additive Manufacturing: Polymers I

Paper Number: 96486

96486 - Physics-Based Filament Adhesion Modeling in Fused Filament Fabrication 

Material extrusion processes such as fused filament fabrication (FFF) are among the most widely used additive manufacturing (AM) technologies. The fused filament fabrication process consists of simultaneously feeding and melting a filament of polymer material through a computer-controlled liquefier. The material then flows through the nozzle under pressure, which must fully solidify while remaining in extruded shape. Deposited layers are fused together as the melted material quickly solidifies to form layers of a solid 3-D object. The key elements are material feed mechanism, liquefier, print nozzle, build surface and environment. The general applications are production of prototypes during product development phase, short series production runs where tooling cost is high, and parts with high geometrical complexity which cannot be produced by means of conventional manufacturing. Often, time evolution of temperature as recorded by thermography and adhesion behavior of filament are investigated by considering main process parameters, such as filament dimensions and material, sequence of deposition and environment temperature. In this paper, thermal behavior of material extrusion and filament adhesion is analyzed. The phenomenon governing the bonding between the adjacent filaments of the FFF process is considered fusion bonding. This paper provides a solution method for filament adhesion using transient heating phenomenon occurring during fused filament fabrication process. The solution method considers appropriate boundary conditions for the sequential filament deposition in time. A technique to calculate the bonding sandwiched between neighboring filament segments was also incorporated in the method. The subsequent numerical model considers the FFF parameters including filament deposition velocity, filament material, diameter, and thermal properties, the temperature of the chamber, sequential filament deposition in order to predict the transient temperature profiles and related adhesion and bonding throughout the FFF process and until the filament cooling is deemed complete. The simulation results on the computed temperature profiles for several consecutive filament segments are given. It is noted that when compared with other filament segments, the latest filament segment always has a higher temperature and a smooth profile of cooling down. It can be observed that the time for welding decreases exponentially as the temperature of the previous filament increases. The weld times are computed for the filament-to-filament bonding using the thermal modeling and simulation scheme. The future work remains as additional predictions that will be studied and the predicted thermal profiles and bonding will be experimentally validated both in terms of temperature profiles and the degree of filament adhesion. This method shows that physics-based modeling can be employed for decision making to provide assistance to the operators for process planning and optimization.

Presenting Author: Shreyas Aniyambeth Rutgers University- New Brunswick

Presenting Author Biography: SHREYAS ANIYAMBETH is a graduate student at Industrial and Systems Engineering of Rutgers University-New Brunswick, New Jersey

Authors:

Shreyas Aniyambeth Rutgers University- New Brunswick
Deepak Malekar Rutgers University- New Brunswick
Tugrul Ozel Rutgers University