Analysis of the conditions and nature of chip formation when grinding wood under conditions of partial selfsharpening of the abrasive tool

The article analyzes the grinding of wood across the fibers, considers the conditions and nature of chip formation, provides a theoretical definition of the tangential cutting force, considers the nature of the wear of the sandpaper under conditions of its partial self-sharpening, and the wear resistance criterion. According to the modern concept of an abrasive tool, its specific features are the absence of a solid cutting edge that any bladed tool has, the presence of an irregular geometric shape of abrasive grains with rounded tops, which causes negative cutting angles. To understand the physical essence of the wood grinding process, it is necessary to have a general idea of the geometric shapes of the grains, how the chip removal process proceeds, what system of forces acts on the abrasive grain. In the process of abrasive cutting of wood across the fibers, the participation of all cutting grains is not equivalent. This phenomenon can be explained by the fact that some of the grains do the work of cutting the fibers, as a result of which for the other part of the grains it remains only to overcome the adhesion between the fibers, that is, to perform the work of elementary shearing. Thus, part of the grains makes a closed cut, as in the case of transverse sawing with circular saws, and part of the grains participates in open cutting across the fibers. In the case of an abrasive tool with predominant clogging, the main wear resistance criterion is the specific grinding performance, since the surface quality not only does not deteriorate as the tool wears, but even tends to improve. When sanding wood across the grain, the abrasive tool is able to work for a longer time and with higher productivity. But since the wear process in this case is accompanied by grain chipping, open areas may appear on the surface of the skin, which, on the one hand, leads to some decrease in grinding productivity, and most importantly, to a deterioration in the quality of the treated surface.

1. Vinogradov V., Sorokin G. Abrasive wear. M., 1995. 224 p. (In Russ.)

2. Grishkevich A.A., Kostyuk O.I. Increasing the service life of the grinding tool when processing wood. Mechanical Engineering and Engineering Science, 2015, no. 3, pp. 17–21. (In Russ.)

3. Kalinin E.P. Theory and practice of abrasive performance management taking into account the bluntness of the tool. SPb., 2006. 40 p. (In Russ.)

4. Ostrovsky V.I. Theoretical foundations of the grinding process. L., 1984. 142 p. (In Russ.)

5. Pereladov A.B., Kamkin I.P. Determination of the wear mode of the tool during grinding. Izvestiya VolgGTU, 2015. no. 3, pp. 24–29. (In Russ.)

6. Sanev V.I., Kamenev B.B., Sergeyevichev A.V. Cutting wood and wood materials. SPb., 2018. 456 p. (In Russ.)

7. Khvatov B.N., Zubkov D.V., Rodina A.A. Investigation of grinding performance with an abrasive tool with self-sharpening grain. Bulletin of TSTU, 2012, vol. 18, no. 4, pp. 1031–1037.

8. Brinksmeier E Advances in Modeling and Simulation of Grinding Processes. CIRP Annals – Manufacturing Technology, 2006, vol. 55, ch. 2, pp. 667–696.

9. Cai G., Feng B, Jin T., Gong Y. Study on the friction coefficient in grinding. Journal of Materials Processing Technology, 2002, vol. 129, pp. 25–29.

10. Carranoa A., James B Geometric Modeling of Engineered Abrasive Processes. Taylora Journal of Manufacturing Processes, 2005, vol. 7, ch. 1, pp. 17–27.

11. Nguyen A.T., Butler D.L. Correlation of grinding wheel topography and grinding performance: A study from a viewpoint of three-dimensional surface characterization. Journal of Materials Processing Technology, 2008, vol. 208, iss. 1-3, pp. 14–23.

12. Sergeevichev A., Belonogova N., Sergeevichev V., Byzov V., Mikhailova A. Investigation of the influence of certain factors on the quality of processing during hard grinding. IOP Conference Series: Earth and Environmental Science. 5th Pan-Russian Scientific Technical Conference on Forests of Russia: Policy, Industry, Science and Education; St. Petersburg. State Forest Technical University. FR. IOP Publishing Ltd., 2020, vol. 574(1). 9 p. DOI: 10.1088/1755-1315/574/1/012072.