Influence of Electro-Erosive Modification Modes for Worn Working Surface of Dental Cutters on Restoration of its Cutting Ability

An experimental assessment has been made of the influence of electro-erosive modification modes for worn working surface of an cutter on the restoration of its cutting ability. The paper provides basic information on dental cutters. The provisions of  the experimental  research  methodology are described, including a description  of  a  device  for  modifying the worn surface of a dental cutter and a device for determining its cutting ability. Experimental data are presented and analyzed that reflect an effect on  restoration of a cutting ability of a worn surface of a dental cutter, voltage of a storage capacitor and  number of holes applied to it during its modification. Rational modes of modifying a worn-out surface of a dental mill that provide the greatest recovery of its cutting ability have been determined in the paper. It has been shown that with increasing voltage, the energy of the electric discharge acting on the treated surface increases, which leads to the formation of a single hole of a larger size on it, including metal flows along its edge that extend beyond the initial contour of the worn cutter teeth. These metal flows on the modified surface of the cutter play the role of peculiar cutting and deforming elements. It has been revealed that in the process of modifying the worn surface of the cutter, it is necessary to ensure that there is no overlap of the holes formed on it, i.e. the distance between the centers of adjacent holes should be greater than or equal to the size of metal deposits at their edges. In this case, the metal flows retain their original shape and have the highest height at these pulse parameters, which ensures a higher cutting ability of the modified cutter surface than when the holes are overlapped.

1. Sabitov V. Kh. (1985) Medical Instruments. Moscow, Meditsina Publ. 175 (in Russian).

2. State Standard 30213–94. Rotary Dental Tools. Test Methods. Moscow, Tariff Classification Manual 279 “Zubovrachebnoe delo”, 1996. 8 (in Russian).

3. Nauk P. E. (1984) Development and Investigation of Technology and Equipment for Manufacturing Injection Needle Point. Odessa. 215 (in Russiam).

4. Kiselev M. G., Monich S. G., Laputina D. G. (2017) Surface Forming with Partly Regular Microrelief with Electrical Discharge Machining. Mekhanika Mashin, Mekhanizmov i Materialov = Mechanics of Machines, Mechanisms and Materials, (1), 64–70 (in Russian).

5. Kiselev M. G., Drozdov A. V., Moscalenko A. V., Bogdan P. S. (2012) Theoretical Substantiation of Rational Parameters of Electric-Mode Processing Wire Tool. Vestnik GGTU imeni P. O. Sukhogo = Bulletin of the GSTU named after P. O. Sukhoi, (3), 3–10 (in Russian).

6. Foteev N. K. (1980) EDM Technology. Moscow, Mashinostroenie Publ. 184 (in Russian).

7. Serebrenitskii P. P. (2007) Modern EDM Technologies and Equipment. Saint-Petersburg, Baltic State Technical University. 228 (in Russian).

8. State Standard 125–79. Gypsum Binders. Technical Specifications. Moscow, IPC Publishing House of Standards, 2002. 12 (in Russian).

9. Kiselev M. G., Drozdov A. V., Monich S. G., Bogdan P. S. (2015) Influence of Self-Tapping Screw Electro-Arc Machining on its Twisting-in in Specimens made of Various Materials and Twisting-Out Procedure. Nauka i Tekhnika = Science & Technique, (5), 3–9 (in Russian).

10. Kozyr D. V. (2013) Study of Parameters of Single Holes Obtained as a Result of EDM Using a Plasma Electrode Tool. Izvestiya Tul'skogo Gosudarstvennogo Universiteta. Tekhnicheskie Nauki = Izvestiya Tula State University, 2 (4), 350–357 (in Russian).

11. Eliseev Yu. S., Saushkin B. P. (2010) Electroerosive Processing of Aerospace Equipment. Moscow, Publishing House of Bauman Moscow State Technical University. 437 (in Russian).