Technological Features in Processing of Conical Lenses

The paper presents the technology of obtaining flat-conical lenses (axicons) by the method of free grinding a work-piece to a flat tool through a layer of abrasive suspension. For this, theoretical and experimental studies of the regularities of stock removal from the base of the cone and its lateral surface have been carried out. The processing modes have been identified that ensure both uniform operation of the flat surface of  the part and enhanced removal of  the allowance in the edge or central zone of this surface. During the study of the processing of the conical surface, the set-up parameters of the technological equipment have been established, at which there is a minimum deviation of the generatrix of the cone from straightness and maximum productivity of the process. The stages of processing conical lenses are proposed, which allow to assign the optimal sequence of operations in the manufacture of this type of parts from blanks of a cylindrical shape in cases where  the ratio of the height of the cone to the diameter of its base H/d £ 0.5. The main stages of processing include: grinding of the bases of cylindrical blanks with maintaining their mutual parallelism with a given accuracy; polishing one of the cylinder bases to achieve the required roughness and deviation from non-flatness; fastening a cylindrical blank to an auxiliary plane-parallel glass plate using molecular cohesion forces; mechanical fastening of a cylindrical work-piece with a collet adapter mandrel for a plane-parallel glass plate; applying the nearest sphere to the second base of the cylindrical blank; drawing a conical surface on the spherical part of a plano-convex lens; grinding and polishing the conical surface to achieve the required roughness  and straightness of the cone generatrix. The degree of efficiency of the setup parameters of the machine has been revealed depending on the technological heredity of the work-piece from the point of view of the distribution of the allowance to be removed over the machined surface.

1. Matsuoka Y., Kizuka Y., Inoue T. (2006) The characteristics of laser micro-drilling using a Bessel beam. Applied Physics A , 84 (4), 423–430. https://doi.org/10.1007/s00339-006-3629-6

2. Marcinkevičius A., Juodkazis S., Matsuo S., Mizeikis W., Misawa H. (2001) Application of Bessel beams formicrofabrication of dielectrics by femtosecond laser. Japanese Journal of Applied Physics, 40 (11a), L1197–L1199. https://doi.org/10.1143/jjap.40.l1197

3. Inoue R., Takakusaki K., Takagi Y., Yagi T. (2010) Micro-ablation on silicon by femtosecond laser pulses focused with an axicon assisted with a lens. Applied Surface Science, 257 (2), 476–480. https://doi.org/10.1016/j.apsusc.2010.07.016

4. Yu X., Ma J., Lei S. (2015) Femtosecond laser scribing of Mo thin film on flexible substrate using axiconfocused beam. Journal of Manufacturing Processes, 20, 349–355. https://doi.org/10.1016/j.jmapro.2015.05.004

5. Dudutis J., Gečys P., Račiukaitis G. (2017) Modification of glass using an axicon-generated non-symmetrical Bessel-Gaussian beam. Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XXII. https://doi.org/10.1117/12.2252966

6. Bardin A. N. (1963) Technology of Optical Glass. Moscow, Vysshaya Shkola Publ. 519 (in Russian).

7. Kozeruk A. S. (1997) Managing the shaping of precision surfaces of machine parts and devices based on mathematical

8. Modeling. Minsk, 1997. 317 (in Russian).

9. Zubakov V. G., Semibratov M. N., Shtandel S. K. (1985) Technology of optical parts. Moscow, Mashinostroenie Publ. 368 (in Russian).

10. Kozeruk A. S., Dias Gonsales R. O., Filonova M. I., Kuznechik V. О., Varopay E. N. (2020) Kinematic analysis of the method increasing the accuracy of treatment of conic surfaces. Vestsi Natsyyanal’nai akademii navuk Belarusi. Seryya fizika-technichnych navuk = Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series, 65 (2), 197-204 (in Russian). https://doi.org/10.29235/1561-8358-2020-65-2-197-204

11. Kozeruk A. S., Dias Gonsales R. O., Sukhotzkiy A. A., Filonova M. I., Kuznechik V. О. (2020) Technological features of formingflat tool for processing axicons. Nauka i Tekhnika = Science and Technique, 19 (4), 297–304 (in Russian). https://doi.org/10.21122/2227-1031-2020-19-4-297-304.