A dynamic model for current-based nozzle condition monitoring in fused deposition modelling

Yedige Tlegenov,Geok Soon Hong,Wen Feng Lu

doi:10.1007/s40964-019-00089-3

Yedige Tlegenov, Geok Soon Hong + Show 1 more

Open Access

https://doi.org/10.1007/s40964-019-00089-3

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Abstract

3D printing and particularly fused deposition modelling (FDM) is widely used for prototyping and fabricating low-cost customised parts. However, present fused deposition modelling 3D printers have limited nozzle condition monitoring techniques to minimize nozzle clogging errors. Nozzle clogging is one of the significant process errors in fused deposition modelling 3D printers, and it affects the quality of prototyped parts in terms of mechanical properties and geometrical accuracy. This paper proposes a dynamic model for current-based nozzle condition monitoring in fused deposition modelling, which is briefly described as follows. First, all the process forces in filament extrusion of the fused deposition modelling were identified and derived theoretically, and theoretical equations of the feed rolling forces and flow-through-nozzle forces were derived. In addition, the effect of the nozzle clogging on the current of extruding motor were identified. Second, based on the proposed dynamic model, current-based nozzle condition monitoring method was proposed. Next, sets of experiments on FDM machine using polylactic acid (PLA) material were carried out to verify the proposed theoretical model, and the results were analysed and evaluated. Findings of the present study indicate that nozzle clogging in FDM 3D printing can be monitored by sensing the current of the filament extruding motor. The proposed model can be used efficiently for monitoring nozzle clogging conditions in fused deposition modelling 3D printers as it is based on the fundamental process modelling.

Highlights

Additive manufacturing (AM) is the process of joining materials layer by layer to build three-dimensional (3D) objects [1], and its applications have been introduced in various engineering areas
Nozzle clogging is one of the significant process errors in fused deposition modelling (FDM) 3D printing, because it has a direct effect on the quality of 3D printed part in terms of mechanical strength and geometrical accuracy
This work proposed a dynamic model for current-based nozzle condition monitoring in FDM 3D printing, and it is based on a theoretical relationship between the extruding motor current and the nozzle clogging condition

Summary

Introduction

Additive manufacturing (AM) is the process of joining materials layer by layer to build three-dimensional (3D) objects [1], and its applications have been introduced in various engineering areas. During the FDM process, a filament material is fed into the heater block where it melts and extrudes onto a build platform via controlled three axis stage. This forms a thin cross-sectional layer of a part, and the process repeats by forming all cross-sectional layers until the part is fully fabricated. Previous studies estimated about 20% failure rate during FDM 3D printing by inexperienced users [14]. This is mainly because FDM 3D printing has number of challenges, such out of filament extruder [15], print head misses the printing platform [15], extrusion stops mid-print [15], print does not stick to the platform [15], print bows out at bottom [15], print peels away from the platform or warps [15], extruder over-extrudes or under-extrudes [15], print has inaccurate dimensional accuracy [16,17,18] or too weak structure [19, 20]

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