THE INFLUENCE OF THE ADDITION OF GRAPHITE ON THE TRIBOLOGICAL PROPERTIES OF POLYLACTIC (PLA) APPLIED IN 3D PRINTING TECHNOLOGY

Tribologia ◽  
2018 ◽  
Vol 277 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Wojciech PAWLAK ◽  
Wojciech WIELEBA ◽  
Janusz KLUCZYŃSKI ◽  
Lucjan ŚNIEŻEK

The article presents the results of studies on the influence of the addition of graphite to a PLA filament on linear wear and the coefficient of friction. A cylinder of 8 millimetre diameter manufactured in Fused Filament Fabrication process, popularly called 3D printing was used as a specimen. Studies were conducted on pin-on-disc testing machine, in which the cylinders mentioned above were paired with a steel disc – the counter-specimen. Specimens used in research were enriched by 5%, 10%, 20%, and 30% of graphite in comparison to the base filament – Natural PLA, which were not enriched with any additions that could improve its tribological properties. The experiment was conducted as a preliminary research. The gained results create a basis to select the optimal composition of additions to the PLA to create a filament with better tribological properties.

Tribologia ◽  
2019 ◽  
Vol 283 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Wojciech PAWLAK ◽  
Wojciech WIELEBA ◽  
Roman WRÓBLEWSKI

This article presents the results of studies on the tribological properties of linear wear and kinetic friction of polylactide processed by 3D printing (FFF) and injection moulding. Research was conducted on a pin on disc apparatus, and the test specimens used were polylactide cylinders with the counter specimen of C45 steel disc. Research was planned and executed with the planned experiment method for two variables: velocity of the counter specimen and pressure. The range of specified values was in the following sections: p = 0.2;0.6 MPa and v m s = 0.2;1.0 . The conducted experiment had a target of defining the influence of a somewhat new method of 3D printing on the tribological properties of materials that might find application in prototyping plain bearings.


Tribologia ◽  
2020 ◽  
Vol 289 (1) ◽  
pp. 57-62
Author(s):  
Wojciech PAWLAK ◽  
Piotr KOWALEWSKI ◽  
Robert PRZEKOP

The article presents the results of basic tribological research of polylactide enriched with MoS2 powder. The research was conducted on a pin-on-disc station. Samples dimensions: 8 mm height, 8 mm diameter, printed in FFF/FDM method. Two mass percentages of addition were created: 1% and 2.5%. As counter-specimen steel (C45) disc was used. Ra roughness of counter-specimen was in the range of 0.3–0.4. The main purpose is to determine optimal, in the light of tribological properties, mass percentage values of additions in polylactide in the 3D printing application. The research has shown that materials with more MoS2 addition would not be a good material for use in the production of prototype bearings, due to increased linear wear. It is also worth noting that the MoS2 addition improves material properties in terms of the 3D printing process. Thanks to the addition, even up to 1%, the required temperature of the printing nozzle has been significantly reduced, as well as flow resistance in the nozzle.


Author(s):  
Anup Darshan ◽  
UmaMaheshwera Reddy Paturi ◽  
Narala Suresh Kumar Reddy ◽  
Srinivasa Prakash Regalla

Now a days for machining operations apart from good tribological properties, the lubricant is also expected to be non-hazardous and non-polluting. When considering the ecological and environmental aspects in machining processes, the use of biodegradable oil can be an alternative source of lubricant due to its positive impact to employee health and environmental pollution. In this regard, our research work uses vegetable based cutting fluids developed from canola and sunflower oil, in an attempt to provide an eco-friendly environment. Experiments are carried out on a pin-on-disc tribometer with tungsten carbide (WC) pin against AISI 4340 steel disc for different sliding times under different environments, thus simulating the machining environment. The tribological properties, wear and friction of vegetable based oils were comparatively investigated with a commercially available mineral oil. Wear tracks and roughness profiles of test specimens were compared by using optical microscope and profilometer respectively. Results indicated that vegetable based canola oil demonstrated excellent tribological properties compared to that of commercial mineral oil.


Author(s):  
Takashi Nogi

Some tribological properties of an ionic liquid were investigated by using a pin-on-disc friction and wear tester. Due to running-in, the coefficient of friction of the ionic liquid decreased with time to a very low value of 0.02 which suggests that the lubrication regime was hydrodynamic at the end of the tests. Anti-wear performance of the ionic liquid was substantially comparable to a paraffin-based oil.


2021 ◽  
Vol 100 (2) ◽  
pp. 58-64
Author(s):  
A.-M. Tomina ◽  
◽  
A. Yerоmenko ◽  
V. Makarov ◽  
◽  
...  

The article considers the influence of discrete (3 mm) basalt fiber on the tribological properties of secondary agglomerated polyethylene terephthalate. It was found that the introduction of the filler reduces the coefficient of friction and the intensity of linear wear of the initial polymer 1,5 and 4,5 times, respectively, reaching the minimum values at a basalt fiber content of 5 mass.%. The obtained results are due to the fact that the appearance of basalt fiber strengthens the polymer matrix that confirms the increase in hardness by 15%, and inhibits the development of cracks on the surface of the composite. The study of the temperature in the contact zone showed its increase that is due to the low thermal conductivity of the filler (0,064 - 0,096); as a result, there is an accumulation of heat in the friction zone. Further increase in fiber content (up to 10 mass.%) leads to a sharp deterioration of the tribological and physico-mechanical properties of basaltoplastics because of the increase in the defect of the material. It is determined that the effective content of filler in the polymer matrix is 5 mass.%. As a result, this composite was recommended for the manufacture of parts for movable joints of agricultural, automotive and metallurgical equipment.


Tribologia ◽  
2018 ◽  
Vol 279 (3) ◽  
pp. 107-111
Author(s):  
Anita PTAK ◽  
Piotr KOWALEWSKI

For the polymeric materials, changing of the temperature causes changes in mechanical and tribological properties of sliding pairs. The goal of the present study was to determine the change in Young's modulus and kinetic friction coefficient depending of the temperature. Three thermoplastic polymers, PA6, PET and PEEK, were tested. These materials cooperated in sliding motion with a C45 construction steel disc. As part of the experiment, the Young's modulus tests (by 3-point bending method) and kinetic friction coefficient studies (using pin-on-disc stand) were carried out. The temperature range of mechanical and tribological tests was determined at T = –50°C±20°C. Comparing the results of mechanical and tribological properties, there is a tendency to decrease the coefficient of friction as the Young's modulus increases while reducing the working temperature.


2014 ◽  
Vol 591 ◽  
pp. 85-88 ◽  
Author(s):  
R. Geetha ◽  
Paulraj Jawahar

Glass filled nylon composites (GFN) and hybrid graphene oxide reinforced glass filled Nylon nanocomposites (GO-GFN) are prepared by blending the required base materials in injection molding machine at processing temperature of 275°C. The specimens prepared are subjected to various mechanical property tests to reveal their hardness, tensile strength and flexural strength. The wear discs of GFN and GO-GFN composites as per ASTM standard are injection molded to analyze the tribological properties using pin on disc tribometer. The pin used is EN 8 Tool steel. The Coefficient of friction for the GFN composites for the wear load of 10 N is 0.28. Addition of 0.003 wt% GO to the GFN system has decreased the coefficient of friction significantly to the value of 0.12. The decrease in C.O.F was correlated with the adhesion film formation in the pin surface. This work confirms the improvement in wear resistance of GO-GFN system which is attributed by the presence of graphene oxide only.


2012 ◽  
Vol 527 ◽  
pp. 217-222 ◽  
Author(s):  
Andrzej Dzierwa ◽  
Pawel Pawlus ◽  
Wieslaw Zelasko ◽  
Rafal Reizer

Wear tests were conducted using a pin-on-disc tester. In the experiment, a steel disc of hardness 40 HRC was put in contact with a steel pin of hardness 64 HRC with spherical end. Disc samples were prepared in order to obtain very similar values of the Sq parameter of one-process and two-process isotropic surfaces. Height of one–process disc surfaces, characterized by the Sq parameter was in the range 0.5 – 6 µm, but of two-process textures 1- 4.5 µm. Dry and lubricated tests, using different contact conditions were carried out. During testing, the friction force was monitored as a function of time. Wear of disc was measured after the test using white light interferometer. Tests under boundary lubrication condition were done using L-AN 46 oil.


2019 ◽  
Vol 17 (2) ◽  
pp. 103 ◽  
Author(s):  
Johannes Otto ◽  
Georg-Peter Ostermeyer

The processes and interactions that occur due to friction in the brake are still not fully understood today. In particular, the processes in the boundary layer have been shown to be responsible for a variation in the coefficient of friction and the associated wear. Dynamic contact structures in the boundary layer are made responsible for this behaviour. Vibration analyses on brake systems usually concentrate on operating vibrations analyses of the brake system components. In order to gain an understanding of the cause of such phenomena and oscillations, it is necessary to understand the mechanism of origin in the contact area. Therefore, highly specialized tribotesters have been developed at the Institute for Dynamics and Vibration to investigate the dynamic processes through experiments and simulative investigations. It can be shown that ultrasonic frequencies are generated in the friction boundary layer. These ultrasonic frequencies could not only be found in pin-on-disc testers, but also in complete vehicle brake systems. It was possible to identify that the vibration signatures between 20 and 80 kHz depend on a whole series of different influencing variables and have no dependence on the testing machine. In connection with the friction theories, it is an open question whether these oscillations can be made responsible as a kind of trigger pulse for the squealing of 1 to 20 kHz. In addition, it is a problem that the parking sensors installed in the vehicle work on an ultrasonic basis in the same frequency range and can therefore lead to failure due to these frequencies.


2021 ◽  
Vol 1163 ◽  
pp. 27-39
Author(s):  
Ganesh R. Chavhan ◽  
Lalit N. Wankhade

In this paper, the specific wear rate (SWR) and the coefficient of friction (CoF) of steel embedded glass/epoxy hybrid composites were examined and compared. Experiments were carried on the pin-on-disc machine on different types of composite materials like plain composite (steel volume 0%) and hybrid composites (steel volume 5% and 10%) pressed against a rotating steel disc (EN 31). Composites were fabricated using the hand-lay-up method. The volume percentage of steel pin/pipe varied from 0 to 10% and glass fiber from 50 to 60%, while the percentage of epoxy was kept 40% stable. The experiments were carried out on a group of samples for duration 20 minutes for different loads of 70N, 80N, 90N, 100N, and 110N with a varying sliding distance of 1000 m, 1250 m, 1500 m, 1750 m, and 2000 m. The results show that the SWR and CoF vary with different load and sliding distance. In general, CoF rises for some time of rubbing, and then it remains constant for the rest of the testing time. The results obtained show that the SWR and CoF increase with increasing sliding distance and load for all the composites. However, SWR and CoF decrease as an increase in the volume percentage of steel. An SWR of hybrid composite is observed to be reduced by 28.02% and 45.98% with an increasing percentage of steel by 5% and 10% respectively. CoF of hybrid composite is observed to be reduced by 14.11% and 24.02% with an increasing percentage of steel by 5% and 10% respectively. At last, the worn surfaces of the hybrid composites were studied through a Scanning Electron Microscope (SEM). Shallow and fine grooves appeared on the worn surfaces of hybrid composites at low loads and cracks were found in large quantities at high load which increased weight loss.


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