Feedback Control of Printing Nozzle by Force Sensing Device with High-accuracy Load Cell

Many of the deposition-based 3D printing technologies work on a predetermined path, which makes it difficult to respond to changes in the layering surfaces. The purpose of this study is to realize a layering motion that maintains a constant pressing force even when the surface to be layered is not flat by measuring the reaction force applied to the nozzle during the layering process and feedback them. By installing a high-accuracy load cell at the base of the nozzle, the vertical reaction forces and moments applied to the nozzle are acquired in real-time. In this paper, we describe a force measurement device using a high-accuracy load cell to measure reaction forces during printing. A feedback system was developed to control the nozzle motion based on the nozzle reaction force. Experiments were conducted on two slope patterns to verify the followability of the nozzle on sloped surfaces. The results of the experiment showed that the printing was achieved by maintaining the pressing force and cross-sectional shape suitable for layering in response to changes in the printing basement.