RU2056230C1 - Method and apparatus for precise treatment of bodies of rotation - Google Patents

Abstract

FIELD: optical engineering. SUBSTANCE: method involves positioning electrode-type tools in equally spaced relation circumferencially of rotating part and imparting synchronous reciprocating motion to electrode-type tools along part and providing periodical feeding in radial direction, with angular rotational speed of part being correlated in predetermined way with selected reciprocating motion speed, which is corrected once in the process of treatment depending on difference of part end diameters obtained. Feeding in radial direction is effectuated prior to even stroke of progressive motion, which is counted after previous feeding stage. Electrode-type tools are moved in synchronism by means of mechanism adapted for feeding tools and made in the form of two pairs of flexible members positioned in parallel one with the other. These members are formed by three longitudinal through slots and one transverse slot, which define tetrahedral prism. Transverse slot makes T-shaped recess with one of longitudinal slots and webs - with two side walls of prism. Flexible members are provided with micrometer-calibrated pushing screws. EFFECT: increased efficiency and simplified construction of apparatus. 3 cl, 1 dwg

Description

 The invention relates to the processing of highly precise bodies of revolution, for example, parts of optical connectors, by EDM grinding.

 A number of technical solutions are known [1, 2] for the precision machining of bodies of revolution, in which high precision machining of the outer surface of rotation of the part is achieved.

 However, in known methods and devices, the use of contact machining due to the presence of machining due to the presence of mechanical deformations and kinematic errors achieves processing accuracy at best within a few micrometers.

 The closest in technical essence to the invention is a method for the precision treatment of bodies of revolution [3] in which the electrode-tool is installed with a gap relative to the surface to be machined, the technological current is applied to the electrode and the part, rotation of the part, relative reciprocating movement of the part and electrode and periodic radial electrode feed to the surface of the part between the strokes of the reciprocating movement. In this case, electroerosive (non-contact) processing is used.

 However, this solution does not allow for maximum input of energy into the interelectrode gap through one electrode-tool with the help of power working current pulses, provided that the specified roughness of the treated surface is maintained, which is a limiting factor for increasing productivity.

 In addition, the indicated technical solution does not optimize the ratio of rotational and translational speeds, which affects the material removal efficiency of the part, and the lack of consideration of the wear of the electrode-tool leads to a decrease in processing accuracy.

 The problem solved by the invention is to increase the accuracy and productivity of processing by matching the speeds of rotation of the part and tool movement, as well as accounting for tool wear.

V, где d размер электрода вдоль оси детали;
n число электродов, и очередную радиальную подачу электродов осуществляют перед четным ходом поступательного перемещения, отсчитанным после предыдущей подачи, при этом после начала обработки для одного из ходов осуществляют измерение диаметров детали в крайних точках, определяют их разность, сравнивают ее с величиной допуска на разность диаметров и в случае превышения полученной разностью величины допуска производят корректировку скорости поступательного перемещения в соответствии с выражением:
V

где γ производительность обработки, мм³/мин;
D диаметр детали;
Δ D изменение диаметра по длине хода, и последующее согласование скорости вращения детали с полученной скорости V. При этом устройство для прецизионной обработки тел вращения снабжено дополнительным электродом с держателем, а механизм подачи электродов выполнен в виде двух пар параллельно расположенных плоских упругих элементов, сформированных из четырехгранной призмы тремя продольными сквозными пазами, один из которых расположен по оси призмы, а два других симметрично относительно него, и поперечным пазом, образующим Т-образный паз с центрально расположенным продольным пазом и перемычки с двумя другими пазами и с двумя боковыми стенками призмы, при этом держатели электродов закреплены на обращенных друг к другу внутренних упругих элементах каждой пары в наружных упругих элементах каждой пары установлены микрометрические винты-толкатели, предназначенные для взаимодействия с внутренними элементами пары, а в одном из наружных упругих элементов установлен дополнительный винт-толкатель для взаимодействия с наружным элементом второй пары, проходящий через выполненные во внутренних элементах отверстиях.To do this, the processing is carried out around the part, the angular speed of rotation ω of the part is coordinated with a given speed V of the reciprocating movement in accordance with the expression
ω

V, where d is the size of the electrode along the axis of the part;
n is the number of electrodes, and the next radial feed of the electrodes is carried out before the even progress of the translational movement counted after the previous feed, while after the start of processing for one of the moves, the diameters of the part are measured at the extreme points, their difference is determined, it is compared with the tolerance on the diameter difference and in case of excess of the tolerance value obtained by the difference, the speed of translational movement is adjusted in accordance with the expression:
V

where γ processing productivity, mm ³ / min;
D is the diameter of the part;
Δ D is the change in diameter along the length of the stroke, and the subsequent coordination of the speed of rotation of the part with the obtained speed V. In this case, the device for the precision treatment of bodies of revolution is equipped with an additional electrode with a holder, and the electrode feed mechanism is made in the form of two pairs of parallel elastic flat elements formed from a tetrahedral prism with three longitudinal through grooves, one of which is located along the axis of the prism, and the other two are symmetrical relative to it, and a transverse groove forming a T-shaped groove with with a centrally located longitudinal groove and jumpers with two other grooves and with two side walls of the prism, while the electrode holders are fixed to the internal elastic elements of each pair facing each other in the external elastic elements of each pair there are micrometer push rods designed to interact with the internal elements pairs, and in one of the external elastic elements an additional pusher screw is installed to interact with the external element of the second pair, passing through in the inner hole feature.

 The proposed method is illustrated in the drawing.

 In a tetrahedral rectangular prism 1, internal flat, elastic elements 2, 3 are made using three longitudinal through grooves 4, 5, 6 and external elastic elements 7, 8 using a transverse groove 9. On internal flat elastic elements 2, 3 through transition insulators 10 11, mounted holders 12, 13 of the tool electrodes 14, 15. The pushers of the internal flat, elastic elements are made in the form of separate micrometric screws 16, 17, for which holes with threads 18, 19 are made in the body of the external elements.

 The mover of the external elastic elements is made in the form of a single micrometer screw 20, for which a hole 21 is made with a thread in the body of the flat elastic element 8, and for its passage with the possibility of contact with the second flat elastic element 7, holes 22, 23 are made in the internal elastic elements. the source 24 of the pulses of the technological current is electrically connected by conductors 25, 26 with the electrodes-tools 14, 15 with the holder 27 of the part 28 using the conductor 29.

 The first stand-alone electrical circuit contains an electrode tool 14, part 28, a signal light 30, switch contacts 31, and a second electrode tool 15, part 28, a signal light 32, switch contacts 33. Electrical contacts 34, 35 and 36, 37 are used to self-powered electrical circuits. The device comprises a slide 38, a faceplate 39 and a spindle 40.

 The proposed technical solution is implemented as follows.

где за γ принимают значение производительности в мм³/мин при операциях электрозионного шлифования.Pre-determine the diameter of the electrode tool from the optimal ratio of 5 d = D, established in practice, where d is the diameter of the electrode tool; D is the diameter of the workpiece surface. Then set ω, V value of the radial feed, and also determine the necessary value for adjusting V value: V

where γ is taken as the productivity value in mm ³ / min during electrosion grinding operations.

Depending on the processing modes and materials of the part and the electrode-tool, this value covers the limits of 0.1-0.5 mm ³ / min. Under given conditions and conditions of processing γ, it can be easily determined empirically or from reference sources. For Δ D take the tolerance on the taper of the manufacture of the part.

V
При двухконтурной обработке с двумя электродами-инструментами n=2, а производительность γ0,12 мм³/мин. Затем приступают к обработке. При этом очередную радиальную подачу электродов осуществляют перед четным ходом поступательного перемещения, отсчитанным после предыдущей подачи, а после начала обработки для одного из ходов осуществляют измерения диаметров детали в крайних точках, определяют их разность, сравнивают ее с величиной допуска на разность диаметров и в случае превышения полученной разностью величины допуска производят корректировку скорости поступательного перемещения в соответствии с выражением

и последующее согласование скорости вращения детали ω с полученной скоростью V.Match the choice of ω and V:
ω

V
When double-circuit processing with two electrodes-tools n = 2, and productivity γ0,12 mm ³ / min Then proceed to processing. In this case, the next radial feed of the electrodes is carried out before the even progress of the translational movement, counted after the previous feed, and after the start of processing for one of the moves, the diameters of the part are measured at the extreme points, their difference is determined, their difference is compared with the tolerance on the diameter difference in case of excess the obtained difference in the tolerance value, the speed of translational movement is adjusted in accordance with the expression

and the subsequent coordination of the rotation speed of the part ω with the obtained speed V.

 The device in this processing method works as follows. Using a micrometer screw 20, the holders 12, 13 of the tool electrodes are removed by an amount sufficient to compensate for their total linear wear when processing a batch of the part, at least during the work shift. And with the help of pushers 16, 17, the internal elastic elements are fed towards each other to create elastic forces that exclude backlash in the system, and to adjust the electrodes-tools and parts. Power is supplied to the electrical circuits with the help of switches 31, 33. Then, the electrodes-tools 14, 15 are moved in the holders until they are in electrical contact (signal lights 30, 32 light up) with the part and are fixed in this position. Having removed the tool electrodes alternately with the help of pushers 16, 17, to the same distance from the part by a few microns from the moment the signal lamps are extinguished, the electrical circuits are switched off using the switches 31, 33. Then, the parts are rotated and reciprocated by the corresponding control elements and include a source of technological current pulses on the electrodes-tools and the part. After that, with the help of a micrometer screw 20, the electrode-tools are synchronously fed to the part at a certain step and processed.

Claims (2)

1. The method of precision processing of bodies of revolution, in which the electrode-tool is installed with a gap relative to the surface to be machined, a technological current is supplied to the electrode and the part, rotation of the part, relative reciprocating movement of the part and electrode and periodic radial electrode feed to the part surface between the strokes are set reciprocating movement, characterized in that the processing is carried out by electrodes-tools located uniformly around the circumference around the part, the angular velocity rotation speed ω details agree with a given reciprocating speed v in accordance with the expression

where d is the electrode size along the axis of the part;
n is the number of electrodes,
and the next radial feed of the electrodes is carried out before the even progress of the translational movement counted after the previous feed, while after the start of processing for one of the moves, the diameters of the part are measured at the extreme points, their difference is determined, their difference is compared with the tolerance on the diameter difference in case of excess the obtained difference in the tolerance value, the speed of translational movement is adjusted in accordance with the expression

where γ is the processing productivity mm ³ / min;
D is the diameter of the part;
DD - change in diameter along the stroke,
and subsequent matching of the rotational speed of the part with the obtained speed v.  2. A device for the precision treatment of bodies of revolution, including a feed mechanism for an electrode-tool with a holder and a technological current source, characterized in that it is equipped with an additional electrode with a holder, and the feed mechanism of the electrodes is made in the form of two pairs of parallel elastic flat elements formed from a tetrahedral prism with three longitudinal through grooves, one of which is located along the axis of the prism, and the other two are symmetrically relative to it, and a transverse groove forming a T-shaped h with a centrally located longitudinal groove and jumpers - with two other grooves and with two side walls of the prism, while the electrode holders are fixed to the internal elastic elements of each pair facing each other, micrometer pushers are installed in the external elastic elements of each pair, designed to interaction with the internal elements of the pair, and in one of the external elastic elements there is an additional micrometric pusher screw designed to interact with the external element the second pair and passing through holes made in the internal elements.

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