SU1349976A1 - Method of lapping - Google Patents

Abstract

The invention relates to abrasive machining and can be used for one- and two-sided argument and free abrasive of parts and instruments. The purpose of the invention is to improve the accuracy and quality of workpieces by reducing the regenerative effect. The parts to be machined have groups in separators between two coaxially mounted tools (on the working surface of the tool) and inform the separators (plans) of rotation around their own axes and the axis of rotation of the tools, while the tools (tool) rotate with absolute angular speed —the second one is determined from the condition w ± ± 2f Vl + 2K / K; where ω and cjg are, respectively, the absolute angular velocities of rotation of the tool and the conditional carrier of the machine’s actuator,; f is the resonant frequency of unrelated oscillations of the system (the first resonant loop of the machine), Hz; K — stiffness of the contact interaction; part — tool through an abrasive layer, N / mm; K - static rigidity of the machine, N / mm. 2 silt, 1 tab. (L Od 4: CO Co 05

Description

13

The invention relates to the field of abrasive machining and can be used for one- and two-sided finishing with a free abrasive of machine parts and devices on the finishing machines.

The purpose of the invention is to increase the accuracy and quality of processing by reducing the effect of the regenerative effect in the process of mechanical abrasive finishing.

FIG. 1 is a diagram of a machine for implementing the method; in fig. 2 the same, top view.

The proposed method can be carried out both on machines for one-sided finishing of parts, and for two-sided.

On the base 1 of the machine, a spindle 2 of the plan drive is mounted with the parts 3 placed on the tool 4.

During processing, a regenerative effect arises, by means of which the reaction of the technological system — the process of abrasive wear-and-ny — the finishing machine is shown in the form of feedback with time lag. This effect plays a double role, because in the process of editing due to wear, like an instrument, both the part and the part are involved in regenerative feedback, which determines the uneven wear of the working surface of the instrument and the deterioration of macro- and microgeometry surfaces of parts.

By weakening the effect of the regenerative effect in the technological system, it is possible to significantly improve the accuracy and quality of processing. For this, the instrument (s) are reported with the absolute speed and direction of rotation determined from the condition

.U), u) gt2f

+ 2K

TO

de u) - absolute angular velocity

.,-one .

vf

tool rotation, with absolute angular speed of rotation of the conditional carrier (ON) of the actuating mechanism of the finishing machine,

the resonant frequency of the unrelated oscillations of the system (the first resonant loop of the amplitude-phase frequency characteristic of the machine), s;

K - rigidity: contact interaction detail - tool through the abrasive layer, N / mm;

K - rigidity of the part relative to the machine bed (static rigidity of the machine), N / mm. The waviness of the working surface of the tool along the path of relative movement, e.g.

Y, A, 4. - iSilS. .d

The waviness of the machined surface of the part on the trail: what are the relative movements of a certain point of the radial profile of the tool on the part is determined by the expression

Y, 4sin «t.g (, (2)

de t

f 2

.

four

T SI current time;

the amplitudes of the initial waviness, respectively, of the working surface of the tool and the surface of the part to be processed prior to the start of processing; respectively, the average intensity of removal and wear, respectively, for the part and the tool;

the cycle time relative to the movement of a certain point of the tool working surface over the part;

frequency of oscillations due to the regenerative effect in the technological system

f

+ 2K

to

(3)

50

55

In expressions (1) and (2), the first term in brackets describes the increment of tool wear and

 removal from the part, and the second term characterizes the waviness of the tool and part, respectively, depending on the effect of the regenerative effect. It can be very large with AND T 2T and may be

is equal to O under the condition ft T T. Then to minimize the waviness of the working surface of the instrument and the macro and

the microgeometry of the part in the process of mechanical refinement the condition T - should be fulfilled. Given that T can be written

de 1

; / J

46

2H4B. 4L14V

OJ U)

42 s

to.

Chg

U) .- and, and W,

 Wj-t02

u) j is the absolute angular velocity of rotation of the plan with details of the separator,.

Then you can write and)) t, - ul, uJft + 2I or i) T 2K

P T

25

Example. On the C-15 machine (Figures 1 and 2), where ОВ is the conditional carrier, ОВ 77.5 mm, tool diameter 320 mm, 139 mm, finishing of the samples made of steel У8А, HRC 53-57, 0 40 m is carried out cast iron priter (NO 120) with an abrasive slurry based on boron carbide with a grain size of 40 km / s T: W 1: 3, 90% glycerin, 10% water, working pressure 0.8 kG / cm, frequency, spindle rotation of product A2 192 rpm tool rotation frequency C) 4 or angular velocity of rotation 35 ny sh. The absolute angular velocity of rotation of the conditional carrier is lOg 0; K 4.03-10 N / mm; K 1,2-10 N / mm; f 5.3 s-h

. Before processing, the maximum deviation from the linearity of the radial profile (tool) of the lapping within 3 nkm, the waviness of the surface of the part in any direction is not

ten

15

20

35

exceeds 0.3 km. Each sample is processed for 3 hours with a continuous supply of abrasive slurry.

The results of processing are presented in the table.

Claims (1)

Invention Formula The method of finishing on the machines for one- or two-sided processing, in which the parts and the tool (s) are reported to have relative movements in the processing plane, characterized in that, in order to improve the accuracy and quality of processing by weakening the regenerative effect during the finishing process, the tool (instruments) rotate with absolute angular velocity, the magnitude and direction of which is determined from the condition 0) 4 in 2f -j , 2 | i de Id and WR - respectively absot Any angular velocity of rotation of the tool and the conditional carrier of the machine actuator,; f is the resonant frequency of unrelated oscillations of the system (the first resonance of the nanoay loop of the amplitude-phase frequency characteristic of the machine); K - contact stiffness interaction part - tool through the abrasive layer, N / mm; K - static rigidity of the machine, N / mm. 192 / 20.1 60 / 6.28 O / O 52-61 192/20, 1 127.5 / 13.36 О / О 28-36 192/20 1 180 / 18,85 О / О 75-87 18-22 Rj 1,2 7-12 Rj 0.1 25-29 Rj 1.6 - / g ili rtrf CJ) fPutl fpt / lZ Compiled by A. Kozlov. Editor N. Tupitsa Tehred L. Serdyukova Order 5219/14 Circulation 715 Subscription VNISh State Committee of the USSR for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, “Projectna St., 4 Proofreader M, Maksimishinets