CC BY
20
УДК 621.921.1
D O. DMITRIEV, S.M. PIVEN, D.D. FEDORCHUK
Kherson National Technical University
USING OF THE MECHANISM WITH PARALLEL STRUCTURES FOR LAPPING MACHINING AND NEW MATERIALS TESTING
A methodology for measuring technical characteristics of combustive engine valve processing quality after lapping processing is presented. A method for evaluating the effectiveness of lapping paste to determine the most optimal is shown. The research results are base for the product technical conditions. Functional using of machine-tool with mechanisms ofparallel structure as a friction machine is checked.
Keywords: combustive engine valve lapping, evaluating method for the lapping paste effectiveness, mechanisms of parallel structures, friction machine
Д.О. ДМИТРОВ, С.М. П1ВЕНЬ, Д.Д. ФЕДОРЧУК
Херсонський нацюнальний техшчний ушверситет
ВИКОРИСТАННЯ ОБЛАДНАННЯ КАРКАСНИХ КОМПОНОВОК З МЕХАН1ЗМАМИ ПАРАЛЕЛЬНО1 СТРУКТУРИ ДЛЯ АБРАЗИВНО1 ОБРОБКИ ТА ВИПРОБУВАННЯ НОВИХ
МАТЕР1АЛ1В
Представлена методологгя вимгрювання технгчних характеристик якостг абразивног обробки поверхонь клапангв двигуна внутрШнього згорання. Розроблено методику оцтки ефективност1 абразивних середовищ при обробцi для визначення найбшьш оптимальног притиральног пасти. Отримано данi для вiдпрацювання технiчних умов виробництва нового зразка притиральног пасти. Перевiрено функцюнальну придаттсть верстатiв з механизмами паралельног структури до використання в якостi машин тертя.
Ключовi слова: абразивна обробка поверхонь клапана двигуна внутрiшнього згорання, методика оцтки ефективностi абразивних середовищ, мехашзми паралельног структури, машина тертя
Д.А. ДМИТРИЕВ, С.Н. ПИВЕНЬ, Д.Д. ФЕДОРЧУК
Херсонский национальный технический университет
ИСПОЛЬЗОВАНИЕ ОБОРУДОВАНИЯ КАРКАСНЫХ КОМПОНОВОК С МЕХАНИЗМАМИ ПАРАЛЛЕЛЬНОЙ СТРУКТУРЫ ДЛЯ АБРАЗИВНОЙ ОБРАБОТКИ И ИСПЫТАНИЯ НОВЫХ
МАТЕРИАЛОВ
Представлена методология измерения технических характеристик качества абразивной обработки поверхностей клапанов двигателя внутреннего сгорания. Разработана методика оценки эффективности абразивных сред при обработке для определения наиболее оптимальной притирочной пасты. Получены данные для отработки технических условий производства. Проверено функциональная годность станков с механизмами параллельной структуры к использованию в качестве машины трения.
Ключевые слова: абразивная обработка поверхностей клапана двигателя внутреннего сгорания, методика оценки эффективности абразивных сред, механизмы параллельной структуры, машина трения.
Statement of the problem
Increase of technical and economic efficiency of the recovery process valve seats of the internal combustion engine cylinders is caused by the necessity to ensure the quality of fine lapping by reducing grinding time and increase the forming accuracy in automobile repair industry. Using of special equipment for this process is economically impractical for automotive repair industry especially for small domestic auto repair companies. That is why the main task for enterprises that produce abrasive paste is achievement of specified parameters with minimal investments. These parameters are precision of saddles surface, minimum roughness of surface, tightness of the connection between saddle and valve, working time reduction, and the reducing of lapping material consumption [1, 2].
Analysis of previous researches and publications
The mechanisms of parallel structure (MPS) are used very widely in workshops, factories and plants nowadays. The massive use of machines and manipulators that have MPS is a modern trend of industry development. One of the biggest tendencies in this trend is the use of standard mechanism and components to
extend the MPS area of application [3]. The area of application extends from manipulators in dentistry to house-size 3D printers, and from the tiny machinery processing to the full-size aircraft-simulators or ships-simulators.
The growing level of competition requires constantly anew of using already existing MPS equipment in order to solve new challenges. Despite the large number of compiling options [4] of these mechanisms more suitable to use the existing mechanisms (machine-tools). Requirements to respond quickly to everyday's changing needs together with harsh economic conditions demands to be prepared to extreme short time for processing restructuring and readjustment.
Existing methods and instruments for lapping materials assessment primarily designed to test the abrasion resistance of radial surface of the cylindrical sample and a flat surface with monotonous or alternate changes with either normal or forced mode and subsequent measurements of abrasive wearing during the tests, and the abrasive ability judged by the values of parameters depending on the wear rate from the pressure. These are currently the standard methods used in industry are:
State standard GOST 23.204-78. "Products wear resistance assurance. Instruments for evaluating wear by the method of cut notches. Technical requirements"
State standard GOST 23.204-78. "Providing products wear resistance. Assessing method of the abrasion ability of the friction surfaces"
State standard GOST 23.205-79 "Products wear resistance assurance. Accelerated life tests by inquiry
method"
State standard GOST 23.208-79 "Ensuring of wear resistance of products. Wear resistance testing of materials by friction against loosely fixed abrasive particles"
State standard GOST 25593-83 "Diamond pastes. Specifications" where is a friction machine «yAC-2M» developed by V. Bakul Institute for Superhard Materials (Kyiv) described.
An example of such application area extension is a work carried out by the Department of transport systems and technical service of Kherson National Technical University (KNTU).
The special computer aided machine-tool with the mechanisms of parallel structure used as a friction machine for implementation the equality of forces and the equality of the cycles condition during the research. The research results and the received technical characteristics of the lapping pastes have become to the new production technical specifications.
This work is performed to the order of private enterprise (PE) "Inter-Sklad"( Kherson) under the service contract r^04/2016 (state registration number 0116U006393) in the research laboratory "Mechanical testing and quality technological equipment» Kherson NTU.
Formulation of research objectives
This work aim was to increase the accuracy of geometric shapes and to determine the optimal mode of lapping abrasive pastes in the processing of surfaces of the seat valve using new components of the lapping pastes. The obtained research results and technical characteristics of the lapping paste prototypes have to become a justification for new technical conditions for the release of the PE "Inter-Sklad". The secondary aim of the research was to test the functional fitness of MPS machinery for using as friction machine and the measurement of technical parameters of process quality [5, 6].
Main part
According to the service contract the PE "Inter-Sklad" provided the laboratory six powder samples of lapping pastes for determination of abrasive fraction size.
Test of lapping materials were performed using specially developed spring device (fig. 1) on the machine-tool SFVPK-4 with MPS manufactured by the patent of Ukraine № 8633 Inv. No. 10483833 (fig. 2)
Special software-driven machine-tool with parallel kinematic SFVPK-4 was applied as friction machine to ensure equal load conditions and lapping cycles. The experiment conditions were quite close to the conditions of manual lapping process, that performing at auto repair shops.
The sequence of tests was:
1. A testing lapping paste evenly distributed on the surface of the lapping plate established stationary in the machine.
2. The testing valve fixed in the spindle-motor by the collet chuck.
3. The machine-tool put in the rotary motion.
4. Put the testing valve down to contact with the lapping plate.
5. Put the system to programmed load with ensured accuracy.
6. Launched lapping countdown timer.
7. Dismantled and washed for subsequent analysis results after the lapping.
Abrasive pastes the ability lapping valve was evaluated for valve weight loss and the lapping plate weight loss before and after friction.
The test mode was: spindle rotation frequency 480 min-1; lapping time 4-15 min; the load to the lapping plate is 20 N.
f) g) h) i)
Fig. 1. The appearance the mashine-tool SFVPK-4 of the test-bench for conducting the research(a) Spring device for testing of lapping quality of given valve lappping pastes (b), paste №. 1. The main fraction is 30-35 microns. A lot of big size particles - 40-50 ^m and a lot of small size particles -10-20 ^m and very small particles.(c) paste№ 2. The main faction is 25-30 microns, presented small part 5060 ^m particles. (d) paste№ 3. The main faction is 25-30 microns, many small particles with size up to
20 ^m. (e) paste №4. The main faction is 30-35microns, several 50 ^m particles. (f) paste №5. The main faction is 40-50 microns, partly 70 ^m particles. (g) paste №6. The main faction is 60-75 microns.
There are particles with size 30 ^m(h), the testing spring device drawing (i)
To ensure fair trials and convenience of valves surface roughness measuring lapping performed on the valve combustive surface that similar by material and condition to valve face and does not alter the research processes. Abrasive ability of given lapping pastes was evaluated by the valves weight loss and the lapping plate weight loss before and after the lapping experiments.
Table 1
The measuring instruments information
The name of measuring instrument Serial number of measuring instrument Main metrological characteristics of measuring instrument The next inspection date
Profilers mod.296 E-347 Э-347/Э-350 Measuring range Ra, 0.02 - 10 micron 1st grade of the accuracy 23.09.2017
Micrometer MK 2986 Measuring range 0-25 mm; Scale interval mm: 0,01 Measurement error, microns: A = + 8 31.08.2016
Caliper miJ-1 7307 Measuring range 0-150 mm; Scale interval mm: 0,05; Measurement error, mm: A = + 0,05 31.08.2016
Ruler HPH -300 n/a Measuring range 0-25mm; Scale interval mm: 1,0 Measurement error, mm: A = + 0,1 31.09.2016
The quality of the surface after lapping valuated by using surface roughness profilometer model 296 (fig. 2) by parameter Ra GOST 2789-73 "Surface roughness. Parameter and characteristics" The microgeometry
BICHHK XHTY№2(61), 2017p.
IHMEHEPHI HA YKH
measurement workplace was additionally equipped with IRIS Waveware digital oscillograph. The profilograph record was making on 3 mm length. The analog output calibration carried on step transition of standard length.
JLf/V
b)
I I be pvofllognun '] mcaronnp plot
t,
r
y
w
d) e)
Fig. 2.a) Surface microgeometry measurement workplace. b) The profilogram obtained after lapping valves combustive surfaces at 8 minutes test: c) The profilogram obtained after lapping valves combustive surfaces at 8 minutes test: the sample of new abrasive paste; d) The profilogram obtained after lapping valves combustive surfaces at 10 minutes test with lapping paste SPM-47 e) The profilogram of the lapping plate after 10 minutes test with lapping paste SPM-47
Ra 1,56
Ra 2.44
1 millimeter
1 millimeter
Given lapping paste samples were tested the surfaces wearing after lapping time 15 min., 10 min., 8 min. and 4 minutes in equal load conditions. The lapping ability comparative tests, the combustive surfaces of the intake valves and the lapping plate metal quality evaluation after lapping conducted in the research by lapping pastes EXPERT (ZOLLEX trade mark) and by new composition paste PP06052016, provided by the customer.
The obtained profilogram of valves surface after lapping recorded in test reports and comparison charts were made for visualization of the pastes lapping ability (fig. 3).
£
x>
ÊP
tp
ising of l; percent
§ in
e
'ra
le C*
Lapping time. minutes
a)
90,00% 80,00% 70,00% 60,00% 50,00% 40,00% 30,00% 20,00% 10,00% 0,00%
Lapping time. minutes
S Sf
O
L4j
□ EXPERT
□ nn06052016
id
10 15
Lapping time. minutes
b)
95%80,00% 60,00%
c) d)
Fig. 3. Comparison of the pastes lapping ability.(a), The roughness parameters Ra (microns) measurements comparison after valves lapping measures by profilometer. (b) The comparing of lapping ability of lapping paste SPM-47 with paste EXPERT (c), The comparing of lapping ability of lapping paste
CHEMPF with paste EXPERT (d)
2,85
2,41
1,9
1,85
,16
1,1
0,88
0,4
4
025
120,00%
30i.nbweHHH aopa3MBH
J,2
100,00%
0,15
0.1
0,05
0,00%
Methods for testing lapping ability were selected according to current regulatory documents at KNTU: State standard GOST 16118-70 "Cylindrical screw springs for compression and stretching from circular cross section wire steel. Technical requirements"
State standard GOST 2789-73 "Surface roughness. Parameter and characteristics." RD 50-98-86 Methodical instructions. "Selection of universal measuring instrumentsof linear dimensions up to 500 mm." 1987
ISO 3611-78 "Micrometers for external measurements" ISO 3599-76 "Vernier callipers reading to 0,1 and 0,05 mm" "Description of the stereoscopic microscope with a universal tripod MBS-2" Manual. Passport 296.0.00.0.00 nC "Workshop profilometer with digital readout device and inductive converter" Model 296, "Caliber" factory, year 1982.
Conclusions
1. Developed a methodology for evaluating the effectiveness of the lapping pastes and practically applied in the form of service contract for PE "Inter-Sklad".
2. This methodology is a metrological application for testing the efficiency of lapping (abrasive) pastes for surfaces finishing processing.
3. The result obtained by using the proposed method put in base for lapping paste production specifications and the new lapping paste for the valves of internal combustion engines put into production process.
3.1. Given lapping paste sample PP06052016 provides increased capacity for material removal by 6070% as compared to lapping paste EXPERT at 8-10 minutes of lapping.
3.2. However PP06052016 paste has the worst indicators on the of surface roughness in the all test
range.
3.3. The surfaces of the valves and the surfaces of lapping plates have deep concentric scratches after processing with lapping paste PP06052016 while the EXPERT paste not only make the surfaces more smooth with a lower roughness but the EXPERT paste also uniforms distribution inequalities in all directions.
3.4. It is advisable to limit admission to the dimensions of the abrasive particles to 35-50 microns in the lapping paste PP06052016.
3.5. Assessment of abrasive capacity of the lapping pastes and quality of the obtained surfaces has shown that the most close to the paste EXPERT is the sample PE # 1 04.07.2016. The paste PE # 1 04.07.2016 provides roughness uniform in all directions with the lowest volume of Rmax.
The geometry and linear values measurements, surfaces microprofiles, the valve mass loss after the lapping were conducted with application of the measuring devices in the certified research laboratory "Mechanical testing and quality technological equipment» Kherson NTU (certificate of attestation RF-112/2015 from 12.11.2015)
References
1. Veremey G.A., An experimental research of the accuracy of overhauled valve seats with the variable cutting conditions/ G.A Veremey, S. P. Sapon // Technological Complexes №1/2 (12), 2015. -p. 62-69
2. Kalchenko V.V., Technological methods of achieving of the "valve-seat" conjugation precision in the internal combustion engine / V.I. Kalchenko, G.A. Veremey //Visnyk of Sevastopol National Technical University, Series "Machines-instrumentation and transport", Edition №121 pp. 18-21 Sevastopol Series "Machines-instrumentation and transport", Edition 121/2011 p. 18-21
3. Kuznetsov Yu.M. Configuration of machine-tools with mechanisms of parallel structure: Monograph / Yu. M. Kuznetsov, D.O. Dmitriev, G.Yu. Dinevich; edit. Yu.M. Kuznetsov. - Kherson PE Vyshemyrskyy 2009 - 456 p .
4. Kuznetsov Yu. N. Realization of frame-configurations conception of machine-tools with mechanisms parallel structure / Yu. Kuznetsov, D. Dmitriev //Journal of the Technical University of Gabrovo, Vol. 54'2017, p. 27-31
5. Dmytriev D. New layout and kinematic drill-milling machines with parallel structure mechanisms /D.O. Dmytriev // Technological Complexes №1 (11), 2015. -p. 25-29
6. Kuznetsov Yu.M., Multilevel system-morphological approach and module principle of planning technological equipment / Yu.M. Kuznetsov, D. O. Dmitriev, S.A. Rusanov, S.M Piven //Visnyk of Kherson National Technical University № 4(55), 2015 y. p. 41-47.
