Material Anisotropy in Additively Manufactured Polymers and Polymer Composites: A Review

Abstract

Additive manufacturing (AM) is a sustainable and innovative manufacturing technology to fabricate products with specific properties and complex shapes for additive manufacturable materials including polymers, steels, titanium, copper, ceramics, composites, etc. This technology can well facilitate consumer needs on products with complex geometry and shape, high strength and lightweight. It is sustainable with having a layer-by-layer manufacturing process contrary to the traditional material removal technology—subtractive manufacturing. However, there are still challenges on the AM technologies, which created barriers for their further applications in engineering fields. For example, materials properties including mechanical, electrical, and thermal properties of the additively manufactured products are greatly affected by using different ways of AM methods and it was found as the material anisotropy phenomenon. In this study, a detailed literature review is conducted to investigate research work conducted on the material anisotropy phenomenon of additively manufactured materials. Based on research findings on material anisotropy phenomenon reported in the literature, this review paper aims to understand the nature of this phenomenon, address main factors and parameters influencing its severity on thermal, electrical and mechanical properties of 3D printed parts, and also, explore potential methods to minimise or mitigate this unwanted anisotropy. The outcomes of this study would be able to shed a light on improving additive manufacturing technologies and material properties of additively manufactured materials.

Numerical Simulation of Sintering of DLP Printed Alumina Ceramics

“…In fact, the shrinkage along the axial dimension is more pronounced than the one measured along the radial dimension. This is due to the nature of the DLP printing working principle itself [41,42]: while on the layer plane, the material behaviour can be assumed to be isotropic if the used slurry had been thoroughly homogenised; along the building direction, more factors such as an optimal layer recovery influence the homogenisation of the material and, consequently, the material behaviour along it. Moreover, the final relative density obtained for the sintered samples, together with SEM images taken for trial 1 and trial 6, are shown in Figure 10 and categorised in terms of dwell time.…”

Effect of spontaneous polarization of tourmaline on the grain growth behavior of 3YSZ powder

“…Consequently, it is widely used in aerospace, medical devices, thermal barrier coatings, piezoelectric components, catalysts, and ceramic capacitors, etc 10–12 . In particular, with the advent of the age of 5G communication, ZrO 2 with high toughness, high wear resistance, and low electromagnetic shielding has become the preferred material for electronic communication devices such as mobile phones 13,14 . High‐performance ZrO 2 ceramics require high‐quality ZrO 2 powder, so the preparation of ultra‐fine, well‐dispersed, and crystal‐stable nano‐ZrO 2 powder is a hot spot in current ceramic research 15 …”

“…[10][11][12] In particular, with the advent of the age of 5G communication, ZrO 2 with high toughness, high wear resistance, and low electromagnetic shielding has become the preferred material for electronic communication devices such as mobile phones. 13,14 High-performance ZrO 2 ceramics require high-quality ZrO 2 powder, so the preparation of ultra-fine, welldispersed, and crystal-stable nano-ZrO 2 powder is a hot spot in current ceramic research. 15 Tourmaline is a silicate with a glass luster, transparent or translucent.…”

Additive manufacturing of parts with three-dimensional continuous fiber reinforcement

“…Наиболее ярко проблему анизотропии можно проследить по результатам стандартных испытаний на растяжение и изгиб, в которых одна группа образцов располагается на столе плашмя (и разрушающая нагрузка работает на деформацию всех слоев одновременно), а другая группа -вертикально (и разрушающая нагрузка вызывает быстрый разлом образца по слоям). Так, в обзорной работе [3] указывается разность прочности в этих двух направлениях от 30 до 77 % для разных пластиков (в первую очередь полиамидов и ABS-пластика) при испытаниях на растяжение.…”

“…В то же время анизотропия характерна и для «наполненных» филаментов -ABS с короткими волокнами до 82 % при растяжении [3] и от 45 до 207 % при изгибе [4]. В исследовании [5] показана анизотропия образцов из чистого полиамида (PA) и полиамида с короткими волокнами (PA/CF), которая составила 175 и 244 % соответственно при испытаниях на растяжение, а при испытаниях на изгиб разность прочности в двух направлениях составила 205 % для PA и 317 % для образцов из PA/CF.…”