Browsing by Subject "PEEK"
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Item Advanced manufacturing of carbon fiber reinforced PAEK composites : bonding and fracture mechanisms(2023-08) Heathman, Nathaniel Thomas; Tehrani, Mehran; Seepersad, Carolyn; Kim, Hyonny; Kovar, DesiderioFiber reinforced composites are used in applications where lightweight, strength, stiffness, fatigue life, and corrosion resistance are critical. Thermoplastic composites (TPC) offer several advantages over thermosetting ones, including higher toughness, recyclability, weldability, and ease of repair. Over the last decade, the interest in in situ consolidation additive manufacturing (AM) of TPCs has increased exponentially due to their potential for rapid cycle out-of-autoclave processes. To this end, several limitations need to be resolved. Specifically in situ consolidation of TPCs usually result in low interlaminar bonding, weak matrix/fiber adhesion, high void content, and low crystallinity. This dissertation aims to provide a new understanding and solutions to these issues. The material system used in this work is carbon fiber reinforced low-melt polyarlyletherketone (LM-PAEK), processed via two AM methods: fused filament fabrication (FFF) and directed energy deposition (DED) in the form of laser-assisted automated fiber placement (AFP). By combining experiments and modeling, this work aims to develop an understanding of how processing parameters affect interlaminar bonding, void development, and crystallinity for both processes. This dissertation also investigates in situ consolidation of TPCs by examining the underlying physics that control bond strength and fracture toughness at inter-layer interfaces. Overall, this dissertation contributes to the knowledge base in the field, toward the adoption of low-energy and high-rate processes for manufacturing high-performance TPC structures.Item Characterization of quartz lamp emitters for high temperature polymer selective laser sintering (SLS) applications(2013-12) Kubiak, Steven Thomas; Beaman, Joseph J.This thesis provides investigation into the interaction between quartz lamp emitters and polyether ether ketone (PEEK) powder. Calculations and experiments concerning the conductivity and emissivity of the powder at various temperatures are performed. The thermal profile of the emitter on a flat powder bed is captured using thermal imaging. The effect of exposing a pile of powder to the emitter and the subsequent thermal gradient through the pile is measured and analyzed. Based on these results, ramifications for the application of these emitters to selective laser sintering (SLS) machines for processing high temperature polymers such as PEEK are discussed.Item Considerations of internal void generation process by observation of melting and solidification behavior in low temperature laser sintering of PEEK(University of Texas at Austin, 2023) Kigure, T.; Yamauchi, Y.; Ninno, T.Laser sintering of PEEK performed below the crystallization temperature has been achieved in previous study by low temperature process that anchors the part to a rigid base plate to suppress warpage during processing. However, significant surface roughness and large internal voids are sometimes generated in the parts built by low temperature process, and there are problems in stability of parts quality. The purpose of this study is to contribute to quality improvement of laser sintering of PEEK by low temperature process. It was attempted that clarify the process of surface roughness and void generation by observing the melting and solidification behavior of the material during process with a video camera. From these observation results, it was assumed that the amount of volume change from powder to liquid due to melting and the amount of shrinkage due to solidification affect part quality such as surface roughness and internal voids.Item Impact Strength of 3D Printed Polyether-ether-ketone (PEEK)(University of Texas at Austin, 2019) Gong, Haijun; Xing, Xiaodong; Nel, JanPolyether-ether-ketone (PEEK) is a high-performance thermoplastic with high heat-, high chemical-, high water-, and high wear-resistance. Its strength and durability also make it highly accepted for a range of industrial applications. 3D printing of PEEK filaments offers a unique quality and flexibility in making PEEK parts for low-volume production or special designs. This study investigates the impact strength of 3D printed PEEK materials. The specimens are fabricated using a fused deposition modeling (FDM) based 3D printer and tested by a pendulum impact tester in compliance with ASTM standard. The testing result is discussed with respect to the processing parameters and the annealing treatment. Impact strength comparison of PEEK materials manufactured by 3D printing and by conventional production is also conducted.Item Investigation into Laser Sintering of PEEK using Commercially Available Low Powder Bed Temperature Machine(University of Texas at Austin, 2021) Kigure, Takashi; Yamauchi, Yuki; Niino, ToshikiPolyetheretherketone (PEEK) is one of the highest performance plastics in terms of heat and chemical resistance and mechanical strength. Laser sintering of PEEK requires high powder bed temperature above 300℃, and this pushes up machine price and pulls down powder recycle rate which leads to high material cost. The authors are proposing a modified laser sintering process which allows the bed temperature to be set lower than recrystallization temperature, namely low temperature process. In this research, bed temperature of 170 ℃, which is typical for PA12 process, and bed temperature of 200 ℃ which is same as previous study were tested. As a result, parts with a high relative density of more than 95% were obtained at both powder bed temperatures, and parts with a tensile strength of 80 MPa were obtained at a powder bed temperature of 170 °C. This shows that laser sintering of PEEK can be processed with a commercially available laser sintering machine resulting in drastic cost cut in terms of machine and material costs.Item Investigation of the Processability of Different PEEK Materials in the FDM Process with Regard to the Weld Seam Strength(University of Texas at Austin, 2019) Wächter, Julian; Elsner, Maike; Moritzer, ElmarDue to the great popularity of the Fused Deposition Modeling (FDM) process, the material market is growing. In particular, processing of high-temperature materials such as PEEK is demanding. The aim of the investigations is to test different PEEK materials regarding their processability in the FDM process. An unreinforced PEEK, a thermally conductive PEEK as well as a carbon fiber reinforced PEEK are investigated. The processability is assessed with the help of the weld seam strength. The assessment of the weld seam strength is carried out by building tests. For this purpose, a special method developed at the DMRC is used. In addition, a welding width factor between the strands deposited on each other is calculated and compared. Finally, a welding factor is determined to enable the comparison between the different materials. With this procedure, the influences of varying nozzle and build chamber temperatures on the achievable weld seam strengths are evaluated.Item Low Temperature Selective Laser Melting of High Temperature Plastic Powder(University of Texas at Austin, 2015) Niino, Toshiki; Uehara, TakashiIn a typical plastic laser sintering or melting system, powder bed temperature is maintained above the recrystallization temperature of the powder material to prevent the parts under process from warping until the whole layers are processed. Although this countermeasure can elegantly suppress the part warpage, heating the powder bed to such a high temperature causes many problems. In case of high temperature plastic such as polyetheretherketone (PEEK), bed temperature should be more than 300°C. Due to this requirement, machine cost is extremely high and powder recyclability is very low. The authors had introduced another countermeasure for the part warpage that anchors the in-process parts to a rigid base plate instead of heating the powder bed above the recrystallization temperature. In the current research, application of this method to PEEK powder is tested, and a simple test piece of which relative density is more than 90% was successfully obtained with preheating temperature of 200°C. In this paper, mechanical performances of obtained parts are presented, and several problems with the process of PEEK powder are discussed as well.Item Mechanical Properties of High-Performance Plastic Polyether-ether-ketone (PEEK) Printed by Fused Deposition Modeling(University of Texas at Austin, 2021) Wang, Zezheng; Runzi, Michael; Gilchrist, Matthew; Gong, HaijunPolyether-ether-ketone (PEEK) is a high-performance thermoplastic material with high heat resistance, high chemical resistance, high water resistance, and high wear resistance. Due to its distinguished strength and durability, PEEK is extensively used for aerospace, automotive, and medical applications. 3D printing PEEK filaments offer a new approach to make PEEK parts, fulfilling specific requirements of geometrical complexity. But the mechanical properties of 3D printed PEEK materials are not further explored. This study investigated the mechanical properties of PEEK materials fabricated using the fused deposition modeling (FDM) 3D printing process. Tensile test, hardness test, and impact test were conducted to the PEEK samples, in compliance with ASTM standards. The testing results were summarized and discussed, compared to the conventionally manufactured PEEK materials. This study also provides insights on employing FDM 3D printing process for making PEEK parts, based on its special mechanical properties and failure mode.Item Mechanical property correlation and laser parameter development for the selective laser sintering of Carbon Fiber Reinforced Polyetheretherketone(2018-08-16) Snarr, Scott Edwin; Beaman, Joseph J.; Fish, ScottThis thesis aims to develop sintering parameters for a novel material to the Selective Laser Sintering process, Carbon Fiber Reinforced Polyetheretherketone (CFR PEEK). A standard process for finding temperature set points and identifying best suitable laser parameters is established and then used on the CFR PEEK material. The standard process ends with several tensile bar builds used to quantify the tensile strength of the varying parameter sets. The best set points and parameters for building in CFR PEEK are identified from the tensile testing results. Additionally, these tensile test results are compared to the thermal history of the tensile bars as recorded by a Mid-Wave Infrared (MWIR) camera in attempt to establish strong correlations and prediction capabilities. R² values show poor correlation between methods that use the average post-sintering temperature to predict measured mechanical strength (R² of .213). In attempt to improve on this correlation, two different thermal measures are established and their correlations with mechanical strength are analyzed. One measure, the minimum average post-sintering temperature, is shown to have a significantly better correlation with measured mechanical strength, achieving an R² of .5409.Item PEEK High Performance Fused Deposition Modeling Manufacturing with Laser In-Situ Heat Treatment(University of Texas at Austin, 2018) Luo, M.; Tian, X.; Shang, J.; Zhu, W.; Li, D.Because of the thermal resistance, high mechanical properties, biocompatibility, PEEK have increasingly extended their application in medicals, aircraft, industrial fields and so on. In FDM, a low crystallinity can be got to limit volume contraction to avoid weak interlaminar bonding, which results in the conflict between high interlaminar bonding and crystallinity. In this study, a CO2 laser device was adopted to improve both the interlaminar shear strength and the crystallinity of PEEK part synchronously in FDM. A series of test was then successively implemented. And after the observation and the analysis of the results, an obvious improvement was got that its interlaminar shear strength could improve over 45%, while its crystallinity could improve over double times for PEEK. Additionally, the process suggests a much potential in developing the gradient distribution of the crystallinity or stiffness in multi-function integration manufacturing for PEEK-like semi-crystalline materials.