Istanbul: Thesis Student Explores Continuous Fiber Composites in FDM 3D Printing http://bit.ly/2IUehwo Although polymers are still the most popular materials used in 3D printing today, many users find themselves limited due to issues with inferior strength and rigidity. Creating composites is a good way to solve these problems, allowing manufacturers to enjoy the benefits of existing plastics while reinforcing them for better performance. In ‘Modelling and path planning for additive manufacturing of continuous fiber composites,’ Suleman Asif, a thesis student at Sabanci University (Instanbul), examines how the addition of continuous fibers can improve fabrication processes with thermoplastic polymers, and add greater strength in mechanical properties. FDM 3D printing is mainly explored here. Issues with FDM 3D printing and these materials, however, tend to be centered around a lack of strength and inferior surface finish, build times that take too long, and inconvenient post-processing. In previous studies, researchers have used short fibers to strengthen thermoplastics, along with carbon nanotubes and fiber composites. Iron and copper have been added to ABS, and the addition of graphene fibers have been noted to add conductivity. In most cases, tensile strength increased but there were issues with interfacial bonding and porosity. The use of short fibers and nanofibers has been explored, but Asif explains that such additions are better for applications like aerospace or automotive. With the use of continuous fiber reinforced thermoplastic (CFRPT) composites, though, both ‘ingredients’ are extruded at the same time from one nozzle and show significant improvement and strengthening. In a different study, researchers loaded both thermoplastic polymer and continuous fibers into the nozzles for FDM printing, with PLA and continuous fibers (some samples consisted of carbon fibers, and some with jute) added separately to another nozzle. While carbon did offer improvements in strength, the jute was not helpful due to ‘degradation of fiber matrix interactions.’ Other tests showed that PLA reinforced with modified carbon showed higher tensile and flexural strength values, demonstrating how powerful ‘preprocessing’ can be.
Previous methods also used ABS and carbon fibers, with two different nozzles and the carbon fibers contained in between the upper and bottom layers of the plastic.
In comparison to pure ABS, the results demonstrated significant strengthening in mechanical properties.
Researchers also attempted to reinforce PLA with aramid fibers, showing ‘notable enhancement.’ Another test evaluated a raw material of commingled yarn, containing polypropylene (PP):
Overall, in reviewing the multitude of studies performed, Asif saw potential for improving mechanical strength, but realizes a need for control of the fiber position within the nozzle to reduce adhesion issues.
The researcher also began examining various path planning processes for acquiring point locations that guide the extruder in depositing materials for filling layers. Asif discovered that most suggested path planning was limiting as it only worked for specific complex structures—some of which would not be appropriate for fabrication of CFRTP composites. Asif suggests that as the algorithms stand currently, there would be problems due to:
3D printing offers an infinite amount of opportunity for designers and engineers around the world, immersed in creation—whether that is industrial, artistic, or completely scientific. There is an immense amount of energy centered around this technology that just continues to grow in popularity, and especially as users continue to refine the processes and materials. Composites are often used to strengthen existing methods and materials, whether in making structural parts for aerospace, regulating electrical composites, or studying conductivity and different techniques for fabrication. Find out more about the use of continuous fiber composites here. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com. [Source / Images: ‘ Modelling and path planning for additive manufacturing of continuous fiber composites’] Printing via 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing https://3dprint.com April 25, 2019 at 08:03AM
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