Published at : 27 Dec 2017
Volume : IJtech Vol 8, No 7 (2017)
DOI : https://doi.org/10.14716/ijtech.v8i7.688
|Dedison Gasni||- Mechanical Engineering, Andalas University, Indonesia
|Ismet Hari Mulyadi||Mechanical Engineering, Andalas University|
|Jon Affi||Mechanical Engineering, Andalas University, Padang Indonesia|
|Andre Yulanda Miswar||Mechanical Engineering, Andalas University, Padang, INdonesia|
Due to increased environmental sensitivity, renewable-based lubricants, and food grade lubricants are being considered potential alternatives to petroleum-based lubricants. Understanding of bio-lubricant in relation to abrasive wear is essential for using ball bearings in industrial implementation. This study focused on wear mechanism on ball bearings lubricated by bio-lubricants. Palm oil and coconut oils were used in this study. Coconut oils were made by two processes, namely dry and wet processing, resulting in three types of oil (virgin coconut oil [VCO], refined coconut oil [RCO], and hydrogenated coconut oil [HCO]). Full-scale bearing life tests were conducted with 300 N load with 2,840 rpm for 6 hours. Method of lubrication was circulating oil by using pump injection to the self-aligning ball bearings. The results show that the main wear mechanism, which impacted on the surfaces of inner race, outer race, and ball for different bio-lubricants, were abrasive and adhesive wear. It found that the abrasion rate was the least severe for VCO. The discrepancies of worn surfaces are thought to be as a result of the physical and chemical properties of bio-lubricants.
Abrasive wear; Ball bearing; Bio-lubricant; Coconut oils; Palm oil
During the operation, rolling contact wear and rolling contact fatigue were occurred on ball bearing. After 6 hours operation with 2850 rpm of shaft rotations and 300 N radial load, the wear formation on the surface of inner race, outer race, and ball was varied with different bio-lubricants. The mechanisms of wear on the bearing were abrasive and adhesive wear. In the ball, the adhesive wear mechanism was very dominant. The wear phenomena for different bio-lubricants on ball bearings were complicated, because lubrication regime in the ball bearings is EHL where viscosity of lubricant is very important, the palm oil is not sufficiently viscose in the case. Thefore, the wear that occurred on the surface of the inner race, outer race, and ball bearing was influenced not only by the physical properties of the lubricant but also by its chemical properties. The important chemical property of the bio-lubricant is fatty acids, which account for lower abrasion. The abrasion rate is smaller for VCO than the other lubricants tested, as it has a high lauric acid (C12:0) content.
From the experiment results, the vegetable oil lubricants were good lubricity compared with the grease lubricant. The worn surface resulting from using the grease lubricant was very severe. It is caused that the starvation phenomenon was occurred on ball bearing because film thickness was reduced in thickness.
The authors are grateful for the financial supported by Directorate of Higher Education of Republic of Indonesia through the Fundamental Research Scheme with contract No. 14/H.16/FUNDAMENTAL/LPPM/2015 and No. 31/UN.16/FD/LPPM/2016 and Research Scheme of Mechanical Engineering Department Andalas University 2017.
Choi, Y., Liu, C., 2007. Spall Progression Life for Rolling Contact Verified by Finish Hard Machined Surfaces. Wear, Volume 262(1-2), pp. 24–35
Day, M.J., 1996. Condition of Monitoring of Hydraulic System. In: Handbook of condition monitoring (Ed. B.K.N. Rao), Elsevier Advanced Technology, Oxford, UK
Dowson, D., 1995. Elastohydrodynamic and Micro-hydrodynamic Lubrication. Wear, Volume 190, pp. 125–138
Dwyer-Joyce, R.S., 2009. Predicting the Abrasive Wear of Ball Bearing by Lubricant Debris. Wear, Volume 233–235, pp. 692–701
Gasni, D., Mulyadi, I.H., Affi, Jon, 2015. Comparison of Physical and Tribological Properties of Coconut Oils Extracted from Dry and Wet Processing. In: Proceedings of Malaysian Tribology Conference, pp. 217–219
Gasni, D., Rahmat, S., 2017. Determining the Lubrication Regime on the Ball Bearings using the Stribeck Curve (Menentukan regime pelumasan pada ball bearing dengan menggunakan kurva Stribeck). Jurnal METTEK, Volume 3(1), pp. 21–28 (in Bahasa)
Fox, N.J., Tyrer, B., Stachowiak, G.W., 2004. Boundary Lubrication Performance of Free Fatty Acids in Sunflower Oil. Tribology Letters, Volume 16(4), pp. 275–281
Honary, L.A.T., 2001. Biodegradable Biobased Lubricants and Greases. Machinery Lubrication Magazine, Issue Number: 200109
Harris, T.A., Barnsby, R.M., 2001. Life Rating of Roller Bearing. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, Volume 2015(6), pp. 577–595
Hanrahan, B., Misra, S., Waits, C.M., Ghodssi, R., 2015. Wear Mechanisms in Microfabricated Ball Bearing System. Wear, Volume 326, pp. 1–9
Johnson, K., 1985. Contact Mechanics, Cambridge university press, Cambridge, UK
Ollofsson, U., Andersson, S., Björklund, S., 2000. Simulation of Mild Wear in Boundary Lubricated Spherical Roller Trust Bearings. Wear, Volume 241(2), pp. 180–185
Lugt, P.M., 2009. A Review on Grease Lubrication in Rolling Bearings. Tribology Transaction, Volume 52(4), pp. 470–480
Pavani, P.N.L., Pola Rao, R., Prasad, C.L.V.R.S.V., 2017. Synthesis and Experimental Investigation of Tribological Performance of a Blended (Palm and Mahua) Bio-lubricant using the Taguchi Design of Experiment (DOE). International Journal of Technology, Volume 8(3), pp. 418–427
Spikes, A.H., Olver, A.V., 2003. Basic of Mixed Lubrication. Lubrication Science, Volume 16(1), pp. 1–28
Siniwsky, M.T., Saniei, N., Adhikari, B., Doezema L.A., 2007. Influence of Fatty Acid Composition on the Tribological Performance of Two Vegetable-based Lubricants. Lubrication Science, Volume 24(2), pp. 101–110
Zhang, J., Drinkwater, B.W., Dwyer-Joyce, R.S., 2006. Monitoring of Lubricant Film Failure in a Ball Bearing using Ultrasound. Journal of Tribology, Volume 128(3), pp. 612–618