Browsing by Author "Khan, Muhammad Raza"

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Optimization of process parameters for accurate reinforcement placement in structural continuous fiber 3D printing
(2024-08-19) Khan, Muhammad Raza
Insinööritieteiden korkeakoulu | Master's thesis
Additive manufacturing has become popular among modern manufacturing technologies. Initially, it was developed for prototyping purposes but now it is being used to manufacture fully functional parts. The reasons for its popularity in modern industries include less material waste, less time consumption and less requirement of expertise. At first, the technology was focused on thermo-plastics and then it incorporated metal manufacturing too. Industrial-grade manufacturing and its applications in sectors such as the automobile and space industries are highly concerned with the mechanical properties of addi-tively manufactured parts. The research has shown the potential of improving strength to weight ratio of polymeric parts by adding fiber reinforcement to them. Carbon fiber is considered to be a good candidate for this purpose be-cause of its lightweight, environmentally friendliness, and high tensile strength. However, the mechanical properties of additively manufactured parts are not only dependent on materials. The properties can be varied greatly by varying process parameters such as layer thickness, flow rate, printing speed and print temperature. These parameters also have a great influence on the build quality of the printed parts. This research experimentally explores the effect of print temperature on the flexural properties of 3D printed carbon fiber-reinforced PA12. Carbon fiber in chopped and continuous form is used to rein-force virgin PA12 using state of the art 3D printer. The specimens are prepared at printing temperatures of 240 °C and 260 °C and tested for flexural strength under a three-point bend test following ASTM D790-17. The response of specimens to load has been shown by load-deflection curves. The results show an increase in flexural strength of 18.63 % by increasing the printing temperature from 240 °C to 260 °C. The addition of chopped carbon fibers in PA12 showed a brittle behaviour while specimens with only continuous carbon fibers showed a ductile behaviour. Furthermore, there is a significant improvement in sur-face finish due to the increase in the printing temperature.