Friction and wear characteristics of polylactic acid (PLA) for 3D printing under reciprocating sliding condition

2019 ◽  
Vol 72 (4) ◽  
pp. 533-539
Author(s):  
Peng Zhang ◽  
Zhichao Hu ◽  
Huanxiong Xie ◽  
Gwang-Hee Lee ◽  
Chul-Hee Lee
Keyword(s):  
Polylactic Acid ◽  
Oscillation Frequency ◽  
Friction And Wear ◽  
Three Dimensional ◽  
Wear Properties ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Friction And Wear Properties ◽  
Dimensional Printing ◽  
Friction And Wear Characteristics

Purpose This paper aims to study the different infill, printing direction against sliding direction and various load condition for the friction and wear characteristics of polylactic acid (PLA) under reciprocating sliding condition. Design/methodology/approach The tests were performed by applying the load of 1, 5, 15 and 10 N with sliding oscillation frequency of 10 Hz for the duration of 10 min at room temperature. Findings The results show that the friction and wear properties of PLA specimen change with a different infill density of printed parts. The oscillation frequency is 10 Hz and the infill density of plate is 50 per cent that shows the best friction and wear properties. Originality/value The potential of this research work is to investigate the tribological characteristics of three-dimensional printing parts with different infill percentage to provide a reference for any parts in contact with each other to improve friction and wear performance. There will be many opportunities exist for further research and the advancement of three-dimensional printing in the field of tribology.

Tribological properties of the epoxy resin-based solid lubricant coating modified by Kevlar fibers

2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Epoxy Resin ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Transfer Film ◽  
Wear Properties ◽  
Content Type ◽  
Friction And Wear Properties

Purpose This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions. Design/methodology/approach Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed. Findings Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings. Originality/value Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.

A three-dimensional shoulder protector based on ergonomics for workers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ran-i Eom ◽  
Yejin Lee
Keyword(s):  
Body Shape ◽  
Three Dimensional ◽  
Health And Safety ◽  
The Body ◽  
Construction Sites ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Functional Studies ◽  
Work Posture ◽  
Dimensional Printing

PurposeThe use of shoulder protectors is strongly recommended when carrying objects on the shoulder to ensure the health and safety of workers. Thus, this study aimed to develop and verify an ergonomic shoulder protector that considers human body shape and carrying posture from an ergonomic perspective. Ultimately, this study will present a shoulder protector with enhanced fit and safety for carrying workers at construction sites.Design/methodology/approachThe shoulder protector was designed and printed using three-dimensional printing technology with variable side neck points and shoulder point heights to reflect the human body's shoulder line shape and to position the carried object stably on the shoulder. The developed shoulder protectors were evaluated in terms of their fit according to the work posture of the carrier, adherence upon motion and durability through structural analysis.FindingsThe design of the shoulder protector for carrying workers followed the shoulder line. It is best placed above the side neck point by 1.0 cm and above the shoulder point by 2.0 cm. Its length is slightly shorter than the human shoulder for superior fit and safety.Originality/valueThe final shoulder protector (FSP) for carrying workers reflects the body curvature while enhancing fit and safety by considering activity and protective factors. As functional studies and evaluations on the need for protectors are scarce, this study provides fundamental data in the evaluation of protective gears.

Rapid manufacturing of copper-graphene composites using a novel rapid tooling technique

2020 ◽  
Vol 26 (4) ◽  
pp. 765-776 ◽  
Author(s):  
Gurminder Singh ◽  
Pulak Mohan Pandey
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Rate Coefficient ◽  
Three Dimensional ◽  
Rapid Tooling ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Dimensional Printing

Purpose The purpose of this study is to study the mechanical, tribological and electrical properties of the copper-graphene (Cu-Gn) composites fabricated by a novel rapid tooling technique consist of three-dimensional printing and ultrasonic-assisted pressureless sintering (UAPS). Design/methodology/approach Four different Cu-Gn compositions with 0.25, 0.5, 1 and 1.5 per cent of graphene were fabricated using an amalgamation of three-dimensional printing and UAPS. The polymer 3d printed parts were used to prepare mould cavity and later the UAPS process was used to sinter Cu-Gn powder to acquire free-form shape. The density, hardness, wear rate, coefficient of friction and electrical conductivity were evaluated for the different compositions of graphene and compared with the pure copper. Besides, the comparison was performed with the conventional method. Findings Cu-Gn composites revealed excellent wear properties due to higher hardness, and the lubrication provided by the graphene. The electrical conductivity of the fabricated Cu-Gn composites started increasing initially but decreased afterwards with increasing the content of graphene. The UAPS fabricated composites outperformed the conventional method manufactured samples with better properties such as density, hardness, wear rate, coefficient of friction and electrical conductivity due to homogeneous mixing of metal particles and graphene. Originality/value The fabrication of Cu-Gn composite freeform shapes was found to be difficult using conventional methods. The novel technique using a combination of polymer three-dimensional printing and UAPS as rapid tooling was introduced for the fabrication of freeform shapes of Cu-Gn composites and mechanical, tribological and electrical properties were studied. The method can be used to fabricate optimized complex Cu-Gn structures with improved wear and electrical applications.

A review of 3D concrete printing systems and materials properties: current status and future research prospects

2018 ◽  
Vol 24 (4) ◽  
pp. 784-798 ◽  
Author(s):  
Suvash Chandra Paul ◽  
Gideon P.A.G. van Zijl ◽  
Ming Jen Tan ◽  
Ian Gibson
Keyword(s):  
Three Dimensional ◽  
Current Status ◽  
Future Research ◽  
Structural Elements ◽  
Construction Time ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Materials Research ◽  
Printing System ◽  
Dimensional Printing

Purpose Three-dimensional printing of concrete (3DPC) has a potential for the rapid industrialization of the housing sector, with benefits of reduced construction time due to no formwork requirement, ease of construction of complex geometries, potential high construction quality and reduced waste. Required materials adaption for 3DPC is within reach, as concrete materials technology has reached the point where performance-based specification is possible by specialists. This paper aims to present an overview of the current status of 3DPC for construction, including existing printing methods and material properties required for robustness of 3DPC structures or structural elements. Design/methodology/approach This paper has presented an overview of three categories of 3DPC systems, namely, gantry, robotic and crane systems. Material compositions as well as fresh and hardened properties of mixes currently used for 3DPC have been elaborated. Findings This paper presents an overview of the state of the art of 3DPC systems and materials. Research needs, including reinforcement in the form of bars or fibres in the 3D printable cement-based materials, are also addressed. Originality/value The critical analysis of the 3D concrete printing system and materials described in this review paper is original.

Investigations of polylactic acid reinforced composite feedstock filaments for multimaterial three-dimensional printing applications

2019 ◽  
Vol 233 (17) ◽  
pp. 5953-5965 ◽  
Author(s):  
Sudhir Kumar ◽  
Rupinder Singh ◽  
TP Singh ◽  
Ajay Batish
Keyword(s):  
Polylactic Acid ◽  
Polyvinyl Chloride ◽  
Three Dimensional ◽  
Wood Powder ◽  
Twin Screw Extrusion ◽  
Melt Flow Rate ◽  
Three Dimensional Printing ◽  
Twin Screw ◽  
Integral Energy ◽  
Dimensional Printing

This paper reports properties of four different filaments prepared from (i) virgin polylactic acid, (ii) polylactic acid reinforced with polyvinyl chloride, (iii) polylactic acid reinforced with wood powder, and (iv) polylactic acid with reinforcement of Fe3O4 prepared with twin-screw extrusion for possible multimaterial three-dimensional printing. The results suggest that the melt flow rate of composite increases with the increase in reinforcements except for wood powder, which has shown a negative trend. Mechanical properties were also reduced with the loading but with the increase in the Fe3O4 content, these properties were improved. It has been observed that with reinforcement of polyvinyl chloride from 10 wt% to 25 wt% peak elongation and break elongation were reduced by 47.61% and 50%, respectively. Further, thermal analysis suggests that all samples were stable but for reinforced samples, the integral energy has decreased significantly in successive cycles. The vibration sample magnetometery of samples suggested that magnetic properties were dependent on the content of Fe3O4 present in the composite.

scholarly journals Remanufacturing of end-of-life glass-fiber reinforced composites via UV-assisted 3D printing

2019 ◽  
Vol 26 (6) ◽  
pp. 981-992
Author(s):  
Andrea Mantelli ◽  
Marinella Levi ◽  
Stefano Turri ◽  
Raffaella Suriano
Keyword(s):  
Mechanical Properties ◽  
Circular Economy ◽  
Three Dimensional ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Glass Fiber Reinforced ◽  
Complex Shapes ◽  
Dimensional Printing

Purpose The purpose of this study is to demonstrate the potential of three-dimensional printing technology for the remanufacturing of end-of-life (EoL) composites. This technology will enable the rapid fabrication of environmentally sustainable structures with complex shapes and good mechanical properties. These three-dimensional printed objects will have several application fields, such as street furniture and urban renewal, thus promoting a circular economy model. Design/methodology/approach For this purpose, a low-cost liquid deposition modeling technology was used to extrude photo-curable and thermally curable composite inks, composed of an acrylate-based resin loaded with different amounts of mechanically recycled glass fiber reinforced composites (GFRCs). Rheological properties of the extruded inks and their printability window and the conversion of cured composites after an ultraviolet light (UV) assisted extrusion were investigated. In addition, tensile properties of composites remanufactured by this UV-assisted technology were studied. Findings A printability window was found for the three-dimensional printable GFRCs inks. The formulation of the composite printable inks was optimized to obtain high quality printed objects with a high content of recycled GFRCs. Tensile tests also showed promising mechanical properties for printed GFRCs obtained with this approach. Originality/value The novelty of this paper consists in the remanufacturing of GFRCs by the three-dimensional printing technology to promote the implementation of a circular economy. This study shows the feasibility of this approach, using mechanically recycled EoL GFRCs, composed of a thermoset polymer matrix, which cannot be melted as in case of thermoplastic-based composites. Objects with complex shapes were three-dimensional printed and presented here as a proof-of-concept.

Multimaterial printing and characterization for mechanical and surface properties of functionally graded prototype

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6741-6753 ◽  
Author(s):  
Sudhir Kumar ◽  
Rupinder Singh ◽  
TP Singh ◽  
Ajay Batish
Keyword(s):  
Polylactic Acid ◽  
Surface Properties ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Surface Hardness ◽  
Functionally Graded ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Dimensional Printing

In this work, an effort has been made for multimaterial three-dimensional printing of functionally graded prototypes of polylactic acid matrix (tensile specimens as per ASTM D638 type IV) followed by characterization of mechanical and surface properties. The work is an extension of previous reported studies on twin-screw extrusion process for the preparation of multimaterial wires as feedstock filaments in possible three-dimensional printing applications. The results of the study suggest that the highest peak strength (46.28 MPa) and break strength (41.65 MPa) was obtained for multimaterial three-dimensional printed samples at infill density 100%, infill angle 45°, and infill speed of 90 mm/s on commercial open source fused deposition modeling setup. Further surface hardness measurements performed on two extreme surfaces (top surface comprising magnetite (Fe3O4)-reinforced polylactic acid and bottom with polylactic acid without any reinforcement) revealed that the hardness for the bottom layer was more than the hardness for the top layer. From fractured surface analysis (using photomicrographs), it has been observed that the three-dimensional printed samples with low infill density resulted into more void formation due to which the performance while mechanical testing was poor in comparison to samples printed with higher infill density. The results are also supported by rendered images of photomicrographs, which revealed that high roughness value of samples printed with low infill density was also one of the reasons for poor mechanical performance of multimaterial three-dimensional printed functionally graded prototypes.

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