CC BY
13
УДК 621.7.013.2
DESIGN FEATURES OF END MILLING CUTTERS FOR TITANIUM ALLOYS MACHINING
S. V. Kozlov, E. O. Shirshov Scientific supervisor - Yu. A. Filippov Foreign language supervisor - S. V. Shelikhova
Reshetnev Siberian State University of Science and Technology 31, Krasnoyarsky Rabochy Av., Krasnoyarsk, 660037, Russian Federation E-mail: [email protected]
The paper deals with the problem of determining the efficiency of processing titanium alloys, depending on the use of cutters with different geometries. Studies in the resource tests of different types of mills showed the relationship between the geometry of the mills and the quality of the machined surface of the part, the level of maximum vibration and the degree of wear of the mills. The experimental confirmation of improved surface quality from the use of cutters with the geometry of Guhring is obtained.
Keywords: milling; oscillations; feed; cutting force; cutting.
ОСОБЕННОСТИ КОНСТРУКЦИИ КОНЦЕВЫХ ФРЕЗ ДЛЯ ОБРАБОТКИ ТИТАНОВЫХ СПЛАВОВ
С. В. Козлов, Е. О. Ширшов Научный руководитель - Ю. А. Филиппов Руководитель по иностранному языку - С. В. Шелихова
Сибирский государственный университет науки и технологий имени академика М. Ф. Решетнева
Российская Федерация, 660037, г. Красноярск, просп. им. газ. «Красноярский рабочий», 31
Е-mail: [email protected]
Рассматривается задача определения эффективности обработки титановых сплавов в зависимости от применения фрез с различной геометрией. Исследования при ресурсных испытаниях фрез различных типов показали зависимость между геометрией фрез и качеством обработанной поверхности детали, уровнем максимальной вибрации и степенью износа фрез. Получено экспериментальное подтверждение улучшения качества обработанной поверхности от применения фрез с геометрией Guhring.
Ключевые слова: фрезерование; автоколебания; подача; сила резания; обработка резанием.
Currently, titanium and its alloys are widely used in aviation, rocket and space production, as well as in transport engineering and shipbuilding, where an important role is played by the low density in combination with high strength and corrosion resistance. With the help of end mills can be performed a variety of work on the processing of not only flat, but also complex surfaces. When milling, the tool wears out on the front and rear surfaces. The wear and durability of the cutters depend on the properties of the material to be processed and the tool material, the cutting conditions, the tool geometry and the quality of the coolant. The higher the hardness and strength of the processed material, the greater the rate of increase in wear and, consequently, less tool life. Under equal cutting conditions, high-speed steel cutters have significantly lower resistance than those equipped with a hard alloy. A great influence on the resistance provided by the geometry of sharpening of the cutter. A feature of milling titanium and its alloys is the appearance during the processing of vibrations (vibrations), which impair the quality and accuracy of processing, as well as leading to accelerated wear of the tool and spindle Assembly. One of
Секция « Технологические и мехатронные системы в производстве ракетно-космической техники»
the most effective ways to reduce the excitation of vibrations is the use of cutters with variable geometry. Thus, the actual scientific and practical task is the possibility of manufacturing milling cutters with effective geometry by Russian manufacturers.
In [1; 2], the results of studies on the suppression of vibrations as a result of minor changes (A® < 4°) in the angles of inclination ® of adjacent teeth of a cylindrical mill are given.
A number of modern foreign tool companies [3-8] offer the market a wide choice of hard alloy end milling cutters, whose main advantage is their high vibration resistance as a result of the transition from the manufacture of equally-inclined helical teeth to differently inclined.
Guhring and a number of other foreign companies offer a different combination of tilt angles of the teeth of end milling cutters ® from 35°° to 45° with a difference in tilt angles of the adjacent teeth A® = 2-4°.
The aim of the study is the possibility of making mills with effective geometry by Russian manufacturers. Tests of ten cutters to determine the efficiency of metal processing and tool wear resistance were carried out at the F650 / 50 Hyundai machining center. The tests were carried out with the mills of two different manufacturers that differ in geometry and the presence of a special wear-resistant coating. These are self-made monolithic carbide cutters without wear-resistant coatings and cutters manufactured according to the technology and drawings of the German manufacturer of cutting tools Guhring (hereinafter Guhring). Comparison of cutters was carried out under the same conditions. The estimated processing time of the part was 11.2 hours. The quality of the treated surfaces is shown in figure.
Machining parts
The figure clearly demonstrate the difference in processing. Self-made cutter No. 1 worked for an hour, progressing intensive wear and tear started, vibration on the treated side surfaces appeared as well as the burrs up to 10-12 mm, the treatment was stopped. The processing was continued processing until its completion after the cutter Guhring installed. The cutter worked 10 hours without deviations and external signs of wear. The results obtained during processing are summarized in table.
Experimental Results
Milling cutter Cutting modes Spindle load, % Time of processing Wear
With the geometry of Guhring n = 130 rpm F = 1300 mm/min 1 10 h Visually absent.
Self-made milling cutter No. 1 n = 130 rpm F = 300 mm/min 2 1 h With a small increase in visible chips and blunting of the cutting edges.
Of all of the above, we can say with confidance that:
- the cutting speed of own-made cutters is 2-4 times lower than the cutting speed of similar foreign cutters;
- quality of the processed surfaces is lower in 1 or 2 classes (if the imported cutters can obtain roughness Ra0, 63, the mills of own production obtain from Ra3, 2 to Ra1, 25);
- resistance of mills of own production at processing of titanium alloys and light alloys is 2-3 times lower than resistance of foreign analogs. Steels show even worse results;
- the use of uncoated cutters for processing titanium alloys with any geometry is irrational and economically inefficient.
- when developing the "good" geometry of the cutters manufactured at the enterprise, it is possible to achieve outstanding results in the metalworking of titanium alloys.
References
1. Budak E. An Analytical Design Method for Milling Cutters With Nonconstant Pitch to Increase Stability, Part 2: Application / E. Budak // ASME Journal of Manufacturing Science and Engineering. 2003. Vol. 125. Р. 35-38.
2. Budak E. Analytical Prediction of Chatter Stability Conditions for Multi-Degree of Systems in Milling. Part I: Modeling / E. Budak, Y. Altintas // Transactions of ASME, Journal of Dynamic Systems, Measurement and Control. 1998. Vol. 120. Р. 22-30.
3. Catalog of the company GUHRING [Electronic resource]. URL: http://:www.guehring.ru (date accessed: 04.02.2019).
4. MITSUBISHI catalogue [Electronic resource]. URL: http://www.mitsubishicarbide.com/EU/ru/ (accessed: 08.02.2019).
5. Directory of company OOO "Tekhtreyd" [Electronic resource]. URL: http://www.techtrade.su/ (accessed: 14.02.2019).
6. Janpo catalogue [Electronic resource]. URL: http://www.cutters.com.tw (date accessed: 15.02.2019).
7. Catalogue of the company ARNO [Electronic resource]. URL: http://www.arnoru.ru /(accessed: 20.02.2019).
8. Maykestag company catalogue [Electronic resource]. URL: http://www.maykestag.com/ ru / (accessed 22.02.2009).
© Kozlov S. V., Shirshov E. O., 2019
