Eklemeli İmalat Yöntemiyle Üretilen PLA Öksetik Tasarımların Mekanik Özelliklerinin İncelenmesi

Abstract

FDM (eriyik biriktirme modelleme), eklemeli imalatta en yaygın kullanılan teknolojilerden biridir. Bu teknolojiyle genellikle PLA (polilaktik asit) gibi çeşitli polimer malzemeler kullanılır. PLA filament, biyolojik olarak parçalanabilirlik, biyolojik uyumluluk ve işlenebilirlik gibi özellikleri nedeniyle 3D baskı için yaygın olarak kullanılan bir polimerdir. Bu çalışmada, PLA hammadde ve hücresel öksetik yapıları tasarımda kullanılmıştır. Öksetik tasarımları metamalzemeler olarak adlandırılır ve ileri özelliklere sahip ve çeşitli geometrilerle elde edilebilen yapılar olarak bilinir. Çalışmada kullanılan öksetik tasarımları missing-rib, re-entrant ve kiral şeklindedir. Öksetik hücresel malzemelerin en büyük avantajlarından biri, hacimli bir malzeme olmamasıdır. İskelet yapısı yüksek mukavemeti düşük yoğunlukta sağlar. Bugün, bu mekanizmaya dayanan mühendislik uygulamalarında kullanılabilecek tasarımlar üzerinde çalışmalar yapılmaktadır. Özellikle tıp alanında ve yüksek hassasiyet gerektiren özel ürünlerin tasarlandığı ve üretildiği alanlarda önemli bir yere sahiptir. 3D baskı teknolojisi ile olan ilişkisini düşündüğümüzde, 3D baskı karmaşık ve kişisel tasarımlar için öksetik yapıların imalatını mümkün kılar. Üretilen parçaların mekanik ve kırılma yüzeylerinin özelliklerini karşılaştırmak amacıyla çekme, basma ve yüzey pürüzlülük testleri uygulanmıştır.

Keywords

• Eklemeli İmalat
• PLA
• FDM
• Öksetik malzemeler

Evaluation of Mechanical Properties of PLA Auxetic Structures Produced by Additive Manufacturing

Abstract

FDM (fused deposition modeling) is one of the most commonly used technologies in additive manufacturing. This technology is used to additively manufacture components from various polymer materials, mostly PLA (polylactic acid), etc. PLA filament is a widely used polymer for 3D printing due to its biodegradability, biocompatibility, and processability. In the study, PLA raw material and cellular auxetic structures were used in the design. Auxetic designs are called metamaterials, they are structures with advanced properties and can be obtained with various geometries. The auxetic designs used in the study are missing rib, re-entrant honeycomb and chiral. One of the biggest advantages of auxetic cellular materials is that it is not bulk material. Having a skeletal structure provides high strength at low density. Today, based on this mechanism, designs that can be used in engineering applications are being studied. It has an important place especially in the medical field, as well as in the areas where high precision and specific products are designed and produced. Considering its relationship with 3D printing technology, 3D printing enables the fabrication of auxetic structures for complex and personal designs. The novelty of auxetic structures comes from their topological features, which display counterintuitive response to the applied load. For the purpose of compare the properties of mechanical tensile, compression, surface roughness tests were applied. It is concluded that the presence of chiral structures improves mechanical performance. The chiral auxetic sample exhibited a maximum stress of 6.68 MPa, the missing-rib auxetic sample displayed a maximum stress of 2.26 MPa, and the re-entrant auxetic sample demonstrated a maximum stress of 3.68 MPa. These results obtained from the tests align well with the range reported in the literature, which falls between 1-12 MPa. The surface roughness of the all-auxtetic structure, perpendicular to the printing direction was higher than the measurements taken parallel to the printing direction.

Keywords

• Additive Manufacturing
• Fused Deposition Modeling
• Auxetic design
• PLA
• Mechanical properties

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