Chế tạo vật liệu in 3D nền nhựa cốt hạt kim loại ABS-Ni bằng phương pháp nghiền và ép đùn cơ học

Fabrication of ABS-Ni composite 3D-printing filaments by using milling and extrusion process

*MINH-THUYET NGUYEN^{(1), (2)}, *JIN-CHUN KIM⁽²⁾   
(1) School of Materials Science and Engineering, Hanoi University of Science and Technology, No.1 Dai Co Viet, Hai Ba Trung, Hanoi 100000, Vietnam.   
(2) School of Materials Science and Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Korea   
(*) E-mail Address: jckimpml@ulsan.ac.kr ; thuyet.nguyenminh@hust.edu.vn

ABSTRACT 

In this study, Acrylonitrile Butadiene Styrene-Nickel (ABS-Ni) composites were fabricated from the initial ABS pellets and Ni powders with the content of Ni of 10 and 20 wt.% by a milling process. The as-fabricated ABS-Ni composite was extruded into filament form and then it was used in a 3D printer to produce some real objects. The results of this work demonstrated the possibility of making and using 3D printing ABS-Ni filaments in the 3D printing industry. 

Keywords: Ni powder; 3D printing, thermal properties, metal-polymer composite, filament 

TÓM TẮT 

Trong nghiên cứu này, vật liệu compozit nền nhựa cốt hạt kim loại Acrylonitrile Butadiene Styrene-Nickel (ABSNi) được tổng hợp bằng phương pháp nghiên cơ học từ các vật liệu ban đầu là hạt nhự ABS và bột kim loại Ni với hàm lượng Ni lần lượt là 10 và 20 % k.l.. Sau khi tổng hợp, vật liệu ABS-Ni (dạng bột) được ép đùn thành dạng sợi với đường kính khoảng 1,75 mm. Sợi ABS-Ni sau đó được dùng như một vật liệu in cho máy in 3D theo công nghệ fused deposition modeling (FDM) để in các mẫu cụ thể. Kết quả cho thấy triển vọng của việc chế tạo và sử dụng vật liệu tổng hợp nền nhựa cốt hạt kim loại ABS-Ni trong lĩnh vực in 3D nói chung và trong công nghệ in 3D-FDM nói riêng. 

Từ khóa: Bột Ni, in 3D, tính chất nhiệt, compozit kim loại-polyme, sợi ngắn 

1. INTRODUCTION 

In recent years, fused deposition modeling (FDM) process has become a useful rapid prototyping technology for various applications. Materials used for FDM basic on thermoplastic materials such as acrylonitrile butadiene styrene(ABS), polyamide, polycarbonate, polyethylene, polypropylene. Among of them, ABS is a strong, durable production-grade thermoplastic. Moreover, because of its excellent dimensional stability, it has been being ideas for pre-production, rapid prototypes that can accurately predict the performance of injection molded parts [1]. Due to the development rapidly of the 3D printing technology that the new materials which could be applied in this field are getting more and more attention, especially polymer composites and metal-thermoplastic  composites.  Moreover,  it  is the fact that the demand for new materials for the FDM process is needed to increase its application domain, such as in rapid tooling and rapid manufacturing areas [1, 2]. On the other hand, the basic principle of the operation of the FDM process offers a great potential for a wide range of materials to be developed and applied including metals and their composites [3-6]. 

Therefore, the study on synthesis and application of the metal-thermoplastic composites in the 3D printing area has got a lot of attention in research and manufacturing. According to the previous study, the main process used for fabrication this kind of materials are mixing in a liquid solution or thermal blending techniques [7, 8] due to the natural properties of thermoplastic composites are dissolved or meltdown under a high temperature that helps for mixing process could be done. However, these methods are not effective ways for reaching the demand of the homogeneous distribution of components in the obtained composite. Therefore, there is plenty of room to fill up in this research area.  This paper presents a fabrication process of new metal-plastic ABS-Ni composite for manufacturing of the filament which is used in 3D printing field. Mechanical milling (MA) which is called as a solid state method is used to synthesize not only alloys, intermetallic compounds, ceramic and inorganic composites, but also metal-organic materials [9]. Therefore, In this work, a ball milling process was used as a functional method to fabricate ABS-Ni powder composites. Subsequently, an extrusion equipment was used to produce ABS-Ni filament which was then used to print a variety of small test parts in an FDM machine. The characterization of the obtained composites and the extruded filament form were observed as well. 

2. EXPERIMENTAL 

2.1. Materials 

In this work, ABS-TR588a pellet(with the dimensions of about 3 mm x 2.5 mm x 1.5 mm) and Ni powder (spherical, -300 mesh, 99,8 %, Alfa Aesar) was used. 

2.2. Preparing of the ABS-Ni composite filament and the as-printed samples 

First, a mixture of 10 and 20 wt.% Ni powder and ABS pellets were prepared, then they are filled into stainless steel vials. About 30 ml of n-Hexane was used as a process control agent to prevent the agglomeration and adhesion during the milling stage. The hardened steel balls (6 mm in diameter) were used with the balls in powder ratio of 10:1. The vial was then placed in a processing chamber of a high energy ball mill (Spexmill). The process was set up with the schedule of running for 10 minutes and stopping for 10 minutes to ensure that the temperature does not exceed 50 °C during the milling time. The milling was carried out in 2 hours of operating. After mechanically milling stage, the milled powders were charged into an extrusion machine with a diameter of 1.70 mm of the nozzle to investigate the possibility of filament making from these materials. The nozzle was heated to reach the starting melting point of the materials around 230-250 °C, then the filament was extruded out and cooled by a cooling system. The as-extruded filament then was used to print a sample in an FDM printing machine. 

3. ANALYSIS 

Morphology of the milled powders was characterized by Field Emission Scanning Electron Microscopy (FE-SEM, JEOL JSM-6500F) with the energy-dispersive spectroscopy (EDS) detector. Thermogravimetric analysis (TGA) was carried out in a nitrogen environment in a range from 25-600 °C with a heating rate of 10 °C min^-1 to investigate the thermal behavior of as-received ABS pellet and milled powders. Structural characterization was performed by Fourier transformed infrared spectroscopy  (FTIR)  using  an  FT-IR  spectrum. The spectra were recorded at a constant temperature from 400 to 4000 cm^-1. 

4. RESULTS AND DISCUSSION

Fig.1 shows the morphology of the obtained ABS-Ni powders with 10 wt.% and 20 wt.% of Ni added into ABS. This results illustrated that by using ball milling technique, ABS-Ni composite powders could be synthesized. Generally, after processing, the shape of the powder has been altered compared to as-received ABS pellets. Thus, the initial ABS pellets were broken-down to powder size. Moreover, the Ni particles combined with ABS to become ABS-Ni composites which were presented in the form of block or cluster shapes due to the agglomeration with the size were evaluated under 200 µm. Although the addition of various contents of Ni, the particles shape and size were almost similar with the size was evaluated under 200 µm. It is the fact that for each composite processing, the homogeneous distribution of the individual components in the matrix is the most important factor that every process tries to achieve. Therefore, in this work the mapping analyses were conducted to evaluate the distribution of Ni in the as-synthesized composites and the results are presented in Fig.2, and Fig.3. In general, it could be said that Ni particles distributed homogeneously in milled powders (Fig. 2a, Fig. 3a). The presence of Ni was also observed clearly in small particles by using mapping area and line scan analysis (Fig. 2b, 2c and Fig. 3b, 3c) indicating that Ni particles contacted and adhered to ABS powders to create ABS-Ni composite in the milling process. However, with 10wt. % of Ni added into ABS, the distribution is not dense due to the low Ni adding content (Fig. 2b). The distribution of Ni is denser with the increase in Ni content up to 20wt.% (Fig. 3b) 

Following the objective of this work, ABS-Ni composites are used for extrusion process to fabricate the filament from, therefore, the behavior of the composite under elevated temperatures was investigated and presented in Fig. 4-The thermogravimetric curves of ABS and ABS-Ni materials at different amounts of Ni. 

Generally, there is no difference in thermal degradation behavior of the ABS-Ni composite is observed compared to initial ABS pellet. The mass loss stages °Ccur on the TGA curves at about 300-400 °C and 450-550 °C for all samples. Both the ABS and ABS-Ni composite are still stable up to 300 °C. The presence of a going-down slope at about 300-350 °C on the TGA curves corresponding to a slight change of the onset temperature of the decomposition. This phenomenon is attributed to the size of powders is significantly smaller than that of ABS pellets that lead to the reducing the time of the heat transfer process in ABS powders. In addition, the remaining of the composites after TGA test were 10 wt.% and 20 wt.% is corresponding to the content of Ni in the composites that  confirms  again  the  homogeneous  of  the obtained composites by milling. 

Fourier transform infrared spectra (FTIR) of ABS and ABS-Ni composites were investigated. The FTIR spectra of all samples are similar and exhibit the peaks corresponding to the particular absorption bands of ABS with no significant changes. Thus, the main absorption bands of ABS are specified through the aromatic double bond C=C bond at 1700 cm^-1, the triple bond C≡N at around 2300 cm^-1 (which represents the existence Acrylonitrile in ABS molecule) and the single bond stretch C-H at around 3000 cm^-1, and all these peaks are observed in both powders (in ABS-Ni composites) and pellet types. The peak intensities in case of the ABS-Ni powders are lower but sharper than that in case of as-received ABS pellet. This could be explained that the ABS circuit has been broken due to the impact of milling leading to a decreasing in molecular weight. However, the main absorption bands of ABS were not changed significantly, that means no interactions between ABS and Ni powder has °C curred. From these results above it could be predicted that the as-prepared ABS-Ni composites are suitable for use in the extrusion process which usually heats the materials up to about 200 °C before extruding them into filament form. Indeed, the prepared ABS-Ni composites were extruded into ABS-Ni filament successfully with the diameter of about 1.70 mm which was presented in Fig. 7. The elemental mapping analysis was taken place on the cross-section surface of the filaments to observe the distribution of Ni particles in ABS matrix and shows in Fig. 6. For both filaments Ni was dispensed in the entire observing surface indicated that it is no matter to use ABS-Ni composite

Fig.7. ABS-Ni filament and  printed samples[/caption] powders in the extrusion process. However, with the adding of 10 wt.% Ni content the distribution is scattered (Fig. 6a), and for the sample with 20 wt.% of Ni expresses a uniform distribution of Ni in ABS matrix (Fig. 6b). Several small parts were printed out in an FDM printer to determine the printable ability of the asextruded filament. Fig.7 presents some products of the FDM process indicates the success of ABSNi composite 3D-printing filament processing and the high potential for applying in the 3D printing industry. 

5. CONCLUSIONS 

According to the results above the ABS powder can be fabricated successfully via milling process. Due to the effects of the collision of the materials (ABS pellet and Ni powders) and steel balls during the milling process Ni particles adhered to ABS powders to form the ABS-Ni composite powders resulting in the regular distribution of Ni in the obtained composite as well as in the filament form. The TGA and FTIR spectra results mentioned that there are nothing changes in the structure of the ABS before and after milling. The successfulness on making ABS-Ni filament and printing the small real objects demonstrates that the new ABS-Ni composite exhibits a great promise for application in the 3D printing field. 

ACKNOWLEDGMENT

This research was supported by The Leading Human Resource Training Program of Regional Neo industry through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and future Planning (grant number) (NRF-2016H1D5A1910587). 

REFERENCES

1. Ludmila Novakova-Marcincinova, Ivan Kuric; Basic and Advanced Materials for Fused Deposition Modeling Rapid Prototyping Technology, Manuf. and Ind.Eng.,11,1, 2012, p. 1338-6549, 2012.
2. N. Sa’ude, M. Ibrahim and M. S. Wahab; Effect of Powder Loading and Binder Materials on Mechanical Properties in Iron-ABS Injection Molding Process, Journal of Applied Mechanics and Materials, 315, p. 582-586, 2013.
3. M. Nikzad, S. H. Masood, I. Sbarski; Thermo-mechanical properties of a highly filled polymeric composites for Fused Deposition Modeling, Materials and Design, 32, p. 3448-3456, 2011.
4. H. H. Nguyen, M. T. Nguyen, W. J. Kim, J. C. Kim, Y. S. Kim, Y. H. Kim, and O. B. Nazarenko; Synthesis of Carbonyl Iron-reinforced Polystyrene by High Energy Ball Milling, J. Korean Powder Metall. Inst, 23, 4, p. 6276-28, 2016.
5. Pringle, A. M., M. Rudnicki, and J. M. Pearce; Wood Furniture Waste-Based Recycled 3-D Printing Filament. Forest Products Journal,  68(1), p. 86-95, 2018.
6. Delphine Depuydt, Michiel Balthazar, Kevin Hendrickx, Wim Six, Eleonora Ferraris, Frederik Desplentere ,Jan Ivens, Aart W. Van Vuure; Production and characterization of Bamboo and flax fiber reinforced polylactic acid filaments for fused deposition modeling (FDM), Polymer composites, 09 August 2018
7. N. M. A. Isa, M. I. Ibrahim, N. Sa’ude and M. Ibrahim; Characterisation of copper filled in ABS material for freeform fabrication, ARPN Journal of Engineering and Applied Science, 11(10), p. 6531-6535, 2016.
8. Masood, S.. & Song, W..,. Development of new metal/polymer materials for rapid tooling using fused deposition modeling, Materials & Design, 25(7),p.587-594, 2004
9. C. Suryanarayana, Mechanical alloying and milling, Progress in Materials Science., 46, p. 1-184, 2001.

Minh-Thuyet Nguyen received the B.S. (2007), M.S. (2009) degrees in Materials Enineering from Hanoi University of Science and Technology, Vietnam and Ph.D. (2017) degrees in Materials science and engineering from University of Ulsan, Korea. He is a lecturer, School of Materials Science and Engineering, Hanoi University of Science and Technology, Vietnam. His Current interests include addi- tive manufacturing (3D-printing), nanomaterials and nanocomposites, powder met- allurgy, Iron and steel making, alloy steels.

Jin-Chun Kim received the B.S. (1990), M.S. (1992), and Ph.D. (1998) degrees from Hanyang University, Korea. He is a Professor, School of Materials Science and Engineering, University of Ulsan, Korea. His Current interests include additive manufacturing (3D-printing), nanomaterials and nanopowders, powder metallurgy and nanocomposites.