Session: 03-08-02: Micromechanics and Multiscale Modeling II

Paper Number: 108423

108423 - Infill Density Effect on the Mechanical Characteristics of Cryo-Treated Petg Structures Developed Using Fused Filament Fabrication Method 

Recent advancements in Fused Filament Fabrication (FFF) moulding with its high flexibility and pace has gained immense popularity in the manufacturing sector. The ability to execute prototyped parts with a wide range of materials in minimal time has promoted the FFF 3D printing. The most commonly available 3D printing materials in the market comprises of poly lactic acid (PLA), thermoplastic polyurethane (TPU), acrylo-nitrile butadiene styrene (ABS), polyethylene terephthalate glycol (PETG), etc. The use of 3D printing technology in the field of cryogenics is limited due to the lack of knowledge about 3D printing material's behavior at cryogenic temperature regimes. Our present research focuses on the impact of cryo-treatment on 3D printed parts and the effect of infill density (ID) for part printing. It is found that the PLA, ABS and TPU properties exhibit high degree of brittle characteristics after one-hour of cryo-treatment in liquid nitrogen (LN2) whereas PETG material retains its plastic nature to a great extent. Furthermore, the extent of cryo-treatment influences on 3D printing parts from PETG by varying infill density were explored. The mechanical properties like tensile strength, impact resistance and surface hardness of 20%, 40%, 60%, 80% and 100% infill density 3D printed PETG specimens were analysed as per ASTM standards and the results confirm an enhancement in tensile, impact and surface hardness values after cryo-treatment compared to untreated parts. In our testing it was observed that the impact resistance exhibits a linear trend with the infill density of 3D printed parts. It is seen that the impact resistance of cryo-treated PETG FFF 3D parts demonstrates an enhancement of 1.5% (20%ID), 4% (40%ID), 6% (60%ID), 10% (80%ID) and 17% (100%ID) compared to untreated parts. Also, it is worthwhile to report a similar trend in surface hardness values after cryo-treatment. The FFF 3D cryo-treated PETG parts exhibit surface hardness values of 10.5% (100%ID), 6.7% (80%ID), 6.1% (60%ID), 5.6% (40%ID) and 4.7% (20%ID) compared with untreated samples. Whereas, in case of tensile strength, at 80%ID, the cryo-treated FFF 3D parts exhibit a maximum enhancement of 90% in tensile strength after cryo-treatment compared to 42% enhancement for 100%ID part. But it is interesting that 20%ID (-52%), 40%ID (-46%) and 60%ID (-38%) all report reduction in tensile strength after cryo-treatment. It is noticed that in terms of tensile strength, toughness and impact resistance, the cryo-treated PETG parts with 80% ID exhibited values more or less similar to that of parts made out of 100% ID making 80%ID as the most promising choice in the selected ID range. This study thereby confirms the optimum infill density for design of parts using PETG filament to be used in cryogenic environments. It is hoped that after further modifications, PETG might be a suitable substitute material for designing inner chambers of cryogen handling and storage vessels.

Keywords: 3D printing; infill density; cryogenic treatment; thermal conductivity; mechanical properties; cryogen storage vessels;

Presenting Author: K E Reby Roy TKM College of Engineering

Presenting Author Biography: Dr. K.E. Reby Roy is currently working as Professor in the Department of Mechanical Engineering, TKM College of Engineering, Kollam. He is also the Dean - International Collaborations and Head - Career Guidance and Placement Unit of TKMCE. He was previously the Dean - Research and Head of all the self financing courses of TKMCE. He received his B.Tech degree from CET, M. Tech from TKMCE and PhD from IIT Madras.
As the Dean of International Collaborations, he has visited 15 countries, signed MoUs with 12 reputed universities and industries in US, South Korea, Malaysia, UK etc. and has developed research collaborations with more than 10 universities around the globe. He received funding from BK21Plus Energy ODA Centre, supported by the South Korean Government and the Department of Mechanical Engineering, Kookmin University, South Korea for his travel to South Korea and initiation of MoU with them.
Dr. K.E. Reby Roy is a devoted researcher in the field of CFD, Cryogenics, Materials and Bio-medical Engineering and has written two book chapters in T&F and published several high-quality international SCI journal publications including in Q1 journals. He is a registered research supervisor in the University of Kerala and Kerala Technological University and 5 doctoral students have received their PhD through his guidance. He has several national and international funded research projects from Kookmin University - South Korea, ISRO, KSCSTE, DST, FIST, SERB-IMPRINT etc. with a total funding amount of more than Rs. 2 crores. He has two patent publications and has filed one patent on hybrid particle reinforced polymer composite for building applications. Presently, Dr. Reby Roy headed Space Technology Laboratory is devoted in developing ultra-high performance light weight materials for future aerospace applications and has achieved 2 Q1 and 1 SCI publication for the present year. He is also an ardent supporter for the concept of valorization in our society. For this he has collaborated with various industries including HLL, Trivandrum for the reutilization of metal oxide and plastic wastes. As an outcome, two eco-sustainable products have been developed in Space Technology Laboratory which is at present under patent examination.
He has also held various positions in the South Kerala Diocese of the Church of South India and was previously member of the Political questions committee, Synod Secretariat, CSI, Chennai.

Authors:

K E Reby Roy TKM College of Engineering
Jiby George Joseph TKM College of Engineering
Aravind Jayarajan TKM College of Engineering