Experimental study of PLA thermal behavior during fused filament fabrication

Shirinbayan

et al. 2021

RPJ

Self Cite

Purpose Fused deposition modeling (FDM) draws particular attention due to its ability to fabricate components directly from a CAD data; however, the mechanical properties of the produced pieces are limited. This paper aims to present the experimental aspect of multi-scale damage analysis and fatigue behavior of polylactic acid (PLA) manufactured by FDM. The main purpose of this paper is to analyze the effect of extruder temperature during the process, loading amplitude, and frequency on fatigue behavior. Design/methodology/approach Three specific case studies were analyzed and compared with spool material for understanding the effect of bonding formation: single printed filament, two printed filaments and three printed filaments. Specific experiments of quasi-static tensile tests coupled with microstructure observations are performed to multi-scale damage analysis. A strong variation of fatigue strength as a function of the loading amplitude, frequency and extruder temperature is also presented. Findings The obtained experimental results show the first observed damage phenomenon corresponds to the inter-layer bonding of the filament interface at the stress value of 40 MPa. For instance, fatigue lifetime clearly depends on the extruder temperature and the loading frequency. Moreover, when the frequency is 80 Hz, the coupling effect of thermal and mechanical fatigue causes self-heating which decreases the fatigue lifetime. Originality/value This paper comprises useful data regarding the mechanical behavior and fatigue lifetime of FDM made PLA specimens. In fact, it evaluates the effect of process parameters (extruder temperature) based on the nature of FDM that is classified as a thermally-driven process.

Section: Discussionmentioning

confidence: 99%

Multi-scale damage analysis and fatigue behavior of PLA manufactured by fused deposition modeling (FDM)

Shirinbayan

et al. 2021

RPJ

Self Cite

“…To track filaments cooling and the re-heating peaks of deposition of successive layers, a very small (d = 80 lm) K-type thermocouple was used (see [28,29] for method description). Results and discussion…”

Section: Online Temperature Measurement Of Filamentsmentioning

confidence: 99%

Toward the understanding of temperature effect on bonding strength, dimensions and geometry of 3D-printed parts

et al. 2020

Self Cite

Fused filament fabrication (FFF), which is an additive manufacturing technique, opens alternative possibilities for complex geometries fabrication. However, its use in functional products is limited due to anisotropic strength issues. Indeed, the strength of FFF fabricated parts across successive layers in the build direction (Z direction) can be significantly lower than the strength in X-Y directions. This strength weakness has been attributed to poor bonding between printed layers. This bonding depends on the temperature of the current layer being deposited-at melting temperature (T m)-and the temperature of the previously deposited layer. It is assumed that depositing a layer at T m on a layer at temperature around crystallization temperature (T c) would enable higher material crystallinity and thus better bonding between previous and present layers. On the contrary, if the previous layer temperature is below T c , material crystallinity will be low and bonding strength weak. This paper aims at studying the significant effect of temperature difference (DT) between previous and current deposited layers temperatures on (1) inter-layers bonding strength improvement and (2) part dimensions, geometry and structure stability. A 23% increase in the inter-layers bonding strength for previous layer temperature slightly higher than T c reported here confirms the above assumption and offers a first solution toward the increase in inter-layers bonding strength in FFF.

“…To track the cooling of filaments and the re‐heating peaks of deposition of successive layers during deposition, very small (d = 80 μm) K‐type thermocouples were used (see [ 23 ] for method description). The schematic of the experiment is presented in Figure 1 containing: the set‐up for in‐process measurement of temperature profile during the deposition, assembling of two methods together, and thermogram of the printed vertical wall with corresponding layers and locations highlighted for temperature profile.…”

Section: Methodsmentioning

confidence: 99%

“…To address this limitation, K‐type thermocouples (d = 80 μm) were added in parallel with deposition without pausing the process or causing damage. [ 23 ] The experimental data were then compared with the predictions obtained by Costa et al [ 24 ] and it was found that there is a sufficient agreement between the experimental and analytical results.…”

Section: Introductionmentioning

confidence: 97%

A comparative in‐process monitoring of temperature profile in fused filament fabrication

Polymer Engineering & Sci

Deligant

Shirinbayan

et al. 2020

Self Cite

Fused filament fabrication (FFF), an additive manufacturing technique, is used to produce prototypes and a gradually more important processing route to get final products. Due to the layer‐by‐layer deposition mechanism involved, bonding between adjacent layers is controlled by the thermal energy of the material being printed. Thus, it is strongly in conjunction with the temperature development of the filaments during the deposition sequence. This study gives out an in‐process set‐up enabling to record temperature profile of two adjacent filaments or a sequence of deposition in various locations during FFF process. The main characteristic of the presented procedure is the possibility of obtaining a global temperature profile resulted from an IR‐camera; parallel to those recorded using a K‐type thermocouple. Needless to say that a K‐type thermocouple accurately records the local temperature at the interface of adjacent filaments. Conversely, an IR‐camera signifies the temperature profile on the captured surface. The obtained results showed that there is a remarkable difference between the cooling rate and re‐heating peaks. The primary outcome of this study is the consideration of results accuracy and the possibility of working on optimization of the obtained temperature profile. Altogether it helps optimize inter‐layer strength while assessing the temperature evolution.