Analysis of wear mechanisms in grinding of polycrystalline diamond with vitrified bonded grinding wheels based on a friction model
Final Report Abstract
The production of cutting inserts made of polycrystalline diamond (PCD) is associated with a high financial outlay due to the high level of wear on diamond grinding wheels. Optimizing this grinding process offers a considerable scientific and economic potential. The overall aim of this research project was to predict the thermo-mechanical loads during the grinding of PCD as a function of the physical properties of a water-based cooling lubricant and the grinding parameters as well as to explain the resulting material removal and grinding wheel wear mechanisms. To cope with the complexity of the tribological system in multi-grain contact, analogy tests were first carried out in single-grain contact (pin-on-disc tribometer). In the tests, the PCD specification, the relative velocity vrel and the cooling lubricant concentration xKSS were varied, with a continuously increasing normal force Fn during the tests. The tangential force Ft and the friction temperature Tr were measured. Mathematical modeling of the single-grain contact created the basis for understanding the multi-grain contact, which was then investigated in forcecontrolled and track-bound grinding tests. The thermal and mechanical process loads as well as the macro and micro wear of the vitrified bonded diamond grinding wheels were measured, analogously to the previous single grain experiments. A finite element simulation of the grinding process was used to determine the local maximum temperatures as a function of the cooling lubricant. Based on the knowledge gained and with the aid of transmission electron micrographs, an explanatory model for the material removal mechanisms and an explanatory model for the grinding wheel wear mechanisms were developed. When grinding PCD with a waterbased cooling lubricant, no thermal material removal and grinding wheel wear mechanisms were detected. The material removal was therefore limited to mechanical effects. The most frequently identified material removal mechanisms were intercrystalline cracks at the diamond/cobalt interface. The grinding wheel wear process showed a clear subdivision into initial wear and continuous wear. These two intervals were characterized by different grinding wheel wear mechanisms. The initial wear was dominated by grain fractures and bonding decline, while abrasion and clogging determined the continuous wear.
Publications
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Analyse der tribologischen Verhältnisse beim Schleifen von polykristallinem Diamant mit einem wassergemischten Kühlschmierstoff. Vortrag auf der Veranstaltung GrindingHub, Stuttgart, 14.05.2024 (Veranstalter: Verein Deutscher Werkzeugmaschinenfabriken e.V. in Kooperation mit Messe Stuttgart und SwissMem)
Breuer, P.
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Tribologische Untersuchungen zur Schleifbearbeitung von polykristallinem Diamant mit wassergemischten Kühlschmierstoffen. Vortrag auf der Veranstaltung Schleiftagung, Fellbach, 31.01.2024 (Veranstalter: refocus consulting GmbH)
Breuer, P.
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Explanatory Model of the Material Removal Mechanisms and Grinding Wheel Wear During Grinding of PCD with Water-Based Cooling Lubricants. Processes, 13(6), 1671.
Breuer, Peter; Reuter, Eike; Prinz, Sebastian & Bergs, Thomas
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Thermal analysis of the polycrystalline diamond grinding process with a water-based cooling lubricant by numerical simulation. The International Journal of Advanced Manufacturing Technology, 136(5-6), 2325-2337.
Breuer, Peter; Gilles, Mick; Knothe, Jan; Prinz, Sebastian & Bergs, Thomas
