3D Microwave printing temperature control of continuous carbon fiber reinforced polymer composites

Continuous carbon fibers show dramatic promise as reinforcement materials to improve the stiffness, strength properties and design ability of 3D printed polymer parts. Current 3D printing methods have a low printing speed because the intrinsic slow and contact needed heat transfer disadvantages of the traditional resistive heating approach. We present a 3D microwave printing method by using the microwave for instantaneous and volumetric heating the continuous carbon fiber reinforced polymer (CCFRP) filament. This allows fabricating CCFRP components with much higher speed compared to traditional 3D printing technologies. To utilize the benefit of high printing speed, the speed-variation 3D microwave printing is applied to adapt the diverse printing path and reduce the printing period. In this paper, a new 3D microwave printing temperature control method by combining the prediction-model and step-proportional-integral-derivative control is researched to reduce the printing temperature difference of the CCFRP filaments during the speed-variation printing process. Three different CCFRP specimens with variation printing speed are tested, including a spanner, an aircraft and a spider from Nazca lines. The experimental results indicate that the new printing temperature control method for 3D microwave printing process dramatically reduces the temperature deviation. Further mechanical testing results indicate that the CCFRP printed with this method has a high tensile strength up to 358 MPa. This technology solved a key problem of 3D microwave printing of continuous carbon fiber reinforced polymer composites and can be used to manufacture complex polymer-matrix composite material

Pengembangan E-Book Fisika Dasar Berbasis Pendekatan Saintifik Pada Materi Usaha, Energi, Impuls, dan Momentum.

This study aims to (1) produce an E-Book based on a scientific approach on the material of Business, Energy, Impulse and Momentum, (2) to find out students' perceptions of E-Book based on a scientific approach on the material of Business, Energy, Impulse and Momentum. This research design uses a 4D research and development design which consists of four stages, namely define, design, develop, and disseminate. The data analysis in this research is descriptive quantitative and qualitative data analysis. From 15 respondents, 66.7% of respondents said that basic physics material is difficult to understand. In the material of Business, Energy, Momentum and Implus, it has a difficulty percentage of 60%. As many as 86.67% of students agree that the scientific approach is suitable for use in the Basic Physics course proces

LiDAR Based Multi-Robot Cooperation for the 3D Printing of Continuous Carbon Fiber Reinforced Composite Structures

3D printing of lightweight continuous carbon fiber reinforced plastics (CCFRP) in three dimensions changes the traditional composite manufacturing processes. The continuous carbon fibers reinforced plastic filament can be printed along the load transmission path and significantly improve the strength of composite structures. Compared to the three-axis computer numerical controlled (CNC) machine based printing process, industrial robots provide the possibility to manufacture complex, spatial and large-scale composite structures. Here, the concept to use multi-robot to print complex spatial CCFRP components simultaneously has been presented. More than one 6 degrees of freedom industrial robots can cooperate with each other and solve the contradiction between structural complexity and printing reachability. During the printing process, the deformation of composite structures may happen, especially for the self-supporting components. Thus, in this paper, a Light Detection and Ranging (LiDAR) method is introduced to detect the deformation of printed composite structure and the movements of two UR robots. To obtain the point clouds of the printed structure, a LiDAR camera D435i has been installed on one robot. A new approach by combining coordinate transformation and iterative-closest-point (ICP) algorithm has been developed to merge the point clouds collected from different shooting angles of the camera

Analysis and optimization of temperature distribution in carbon fiber reinforced composite materials during microwave curing process

Vacuum assisted microwave curing technologies and modified optical sensing systems have been employed to investigate the influence of ply orientation and thickness on through-thickness temperature distribution of carbon fiber reinforced composite laminates. Two different types of epoxy systems have been studied. The results demonstrated that the ply orientation did not affect the temperature distribution of composite materials. However, the thickness was an important influencing factor. Nearly 10 ◦C temperature difference was found in 22.5 mm thick laminates. Through analyzing the physical mechanisms during microwave curing, the temperature difference decreased when the heat-loss in surface laminates was reduced and the absorption of microwave energy in the center laminates was improved. The maximum temperature difference of the samples formed using the modified microwave curing technologies in this research could be reduced by 79% to 2.1 ◦C. Compared with the 5.29 ◦C temperature difference of laminates using thermal heating process, the maximum temperature difference in laminates using modified microwave curing technologies was reduced by 60%, and the curing time was cut down by 25%

Small-Size Coaxial Resonant Applicator for Microwave Heating Assisted Additive Manufacturing

This article introduces the design and analysis of a small-size coaxial resonant applicator for high-speed microwave heating-assisted additive manufacturing of multiple materials, such as continuous carbon fiber reinforced polymer composites, thermoplastic, and metal parts. The elaborated coaxial resonant applicator reduces the size and has a resonant frequency between 2.4 and 2.5 GHz. A TEM wave is stimulated in the applicator where the electrical field is polarized perpendicular to the filaments and, therefore, allows a maximum penetration depth. The electrical conductive filament is designed as a part of the inner conductor to enhance coupling efficiency. To prevent microwave leakage induced by the conductive material, a compact quarter wavelength filter was developed. The equivalent circuit of the filter was used to analyze the influence of structural parameters on the resonance frequency. The filter has been tested and good agreement between measured and simulated results is obtained. The heating behavior with varying input power has been investigated for polyamide, polylactic acid, and continuous carbon fiber reinforced polyamide filaments