# Experimental Investigation on Effect of Temperature on FDM 3D Printing Polymers: ABS, PETG, and PLA
## 3 Results  
In order to clarify the need for 4D printing for the specific geometry that is designed, Figure 2 is put together. If the desired shape has parts that are too thin and require support material, removing support after the print becomes impossible, causing breakage in the actual parts. However, with 4D printing, one can print a part flat, and by fluctuating the temperature, the part can get into the desired curvature. As mentioned, the samples were printed flat. After the printing process was performed, the samples were moved to the station where the camera was set. Just before the 15 min heating would end, the camera was set to begin recording at 1080 pixels at 30 frames per  
Figure 2: Three-dimensional printing versus 4D printing processes. second (fps). When the heating period (i.e., 15 min) ended, the sample currently being heated was removed from the heated bed using a plastic scraper and a dental pick. The sample was then placed in a given location (i.e., consistent for all samples). The samples were filmed until approximately one minute before the next sample finished heating. During this time period, it was observed that samples would reach room temperature. Figure 3 represents the left side of ABS, PETG, and PLA samples for the three different heating temperatures of 85, 105, and 125 \({}^{\circ}\)C. This figure is a visual representation of how curling would occur in these samples with the tracking point at the tip of each sample. For each configuration, there were three samples analyzed. Firstly, it is clear that ABS has a repeatable behavior for lower heating temperatures compared to PLA. Additionally, the change in curvature is visually shown to be greater for PLA compared to PETG and ABS. However, in order to have quantitative results, Figure 4 is provided. It should be mentioned that in order to control the undesired curling of the other parts of the 3D-printed part, a thick middle section was printed in our samples. These sections were not attached to the paper; therefore, there was no change in the thermal coefficient of expansion; hence, they acted as the base of the parts. Figure 4 represents the absolute x values for each sample as the samples were cooling down. It should be noted that they all start from the farther end of samples, which is away from the origin (0,0), which is defined to be close to the center of the 3D-printed part, and they travel toward the center. Based on Figure 4's results, the minimum traveled distances are experienced by PLA and ABS for lower heating temperatures, while the maximum traveled distances are observed in PETG and PLA at higher temperatures. This is shown by comparing Figure 4A,G with Figure 4F,I. This is a clear indication that PLA is more responsive to temperature dosage during the curling process compared to ABS and PETG. This is shown by changing temperatures for each sample. The changes in ABS and PETG as we increase the temperature are smaller compared to those in PLA. For PLA samples, the change in displacement from 85 degrees to 105 degrees and finally to 125 degrees is more distinct than the ones shown in ABS and PETG. However, in order to understand how quickly they respond, the velocity graphs are also shown in Figure 5.  
Figure 3: Visualization of curling process for ABS, PETG, and PLA samples under three different heating conditions: 85, 105, and 125 \({}^{\circ}\)C.  
Figure 5 shows that as time passes during the cooling process, the rate of change of curling slows down for all of the samples regardless of the initially heated temperature. However, PLA and ABS have higher velocities at higher temperatures during the first 100 s compared to when they are heated to only 85 \({}^{\circ}\)C. Therefore, if one needs a faster curling process to occur, they might need to expose the PLA and ABS to higher temperatures. This does not necessarily hold true for PETG samples. Their rate of change does not seem to be a function of initial temperature. In order to have a full visualization of the motion of the 3D-printed strips, Figure 6 is developed.