Minimizing the impact of filament quality on FDM parts using feed forward control

The quality of fused deposition modeling (FDM) parts is strongly influenced by variations in filament geometry and consistency, particularly diameter deviations that disrupt the intended volumetric flow into the melt zone. These fluctuations can lead to poor inter-layer bonding, internal voids, and reductions in mechanical performance.
This research presents a Feed Forward (FFC) Control system developed to minimize the effect of filament dimensional variability on print quality. The system employs dual orthogonal diameter sensors to continuously monitor real-time filament geometry and compute the instantaneous volumetric error relative to the nominal 1.75 mm target. Using this data, the algorithm preemptively adjusts feed rate before deposition, compensating for under or over extrusion without relying on slower feedback corrections.
The performance of the FFC system is evaluated through comprehensive experiments involving over 200,000 logged data points and 240 printed specimens across multiple commercial filament vendors. Key performance indicators include diameter precision, pressure decay rate (leaks) in sealed tubes and tensile strength of coupons. Results show that FFC control significantly improves extrusion uniformity, leading to higher tensile strength and lower leak rates. Furthermore, statistical analysis reveals that filament prices do not consistently correlate with geometric or mechanical quality; in several cases, lower cost filaments achieved equivalent or superior performance to premium filaments.
In summary, this study delivers a practically deployable Feed Forward Control strategy for desktop FDM printers that compensates for filament variability using low-cost sensors and open-source firmware modifications.