SU1288039A1 - Method for grinding control - Google Patents

Abstract

This invention relates to methods for controlling profile grinding. The purpose of the invention is to improve the quality of processing, the elimination of anti-defects and increase the stability of processing. For this, the adjustable parameter is fixed at the end of the embedding stage, and the value of the setpoint, at which level the parameter is stabilized, is determined by calculating the product of the fixed parameter value by the ratio of the permissible and maximum specific values of this parameter. The current specific value of the adjustable parameter is determined at the stage of embedding as the ratio of the increment of this parameter to the increment of the geometrical parameter of the cutting zone. 4 il. (C (L oo oo oo o 00 co

Description

f

The invention relates to mechanical engineering, in particular to the machine tool industry, and can be applied in the development of machine tools with software and adaptive control, for example, machines for grinding the thread of the details of the screw-and-screw gear drive.

The purpose of the invention is to improve the quality of processing during profile grinding by eliminating grinding de1288039

the parameter depends on the thermophysical properties of the material being processed (K s. y) and inversely proportional to the square root of the instantaneous effect of the heat source t.

At the embedding stage, using the power sensor 8 and the axial stir sensor 9, the profile of the circle measures the value of the adjustable parameter P and the axial shifts, respectively. Axial re-strife and stability enhancement; treatment of the circle profile is measured from

15

20

thirty

ki by adjusting the specific value of the power parameter of the cutting process.

FIG. 1 shows a block diagram of the device; in fig. 2 is a diagram of the formation of a threaded groove; in fig. 3 and 4 - experimental and calculated dependences, in accordance with the use of the method,

The block diagram contains a machine I, for example, a thread grinder, equipped with a CNC device 2, a transverse-feed sensor 3, a micro-computer 4, a communication unit 5, an analog-to-digital converter 6, a feed drive 7, a cutting power sensor 8 and a sensor 9 for axial displacement of the grinding wheel.

Work during grinding, for example, the threads of gear screws “screw-nut rolling, is carried out as follows. 25

The necessary adaptive control algorithms in the form of a set of programs and subprograms are stored in the memory of microcomputer 4. Immediately prior to processing, through the communication unit 5 in microelectric 4, a priori information is transmitted from the CNC device 2 about the process (radius profile of circle r and pre-formed thread groove , the diameters of the workpiece d and the grinding wheel D, the allowable value of the specific value of the adjustable parameter ccdp, and the initial processing conditions: the grinding depth t and the angular speed of the workpiece (co). Valid value The specific value of the controlled parameter is determined, for example, from a known dependence

2q-v7

VnS / TcY (U

where T is the temperature in the contact zone, ° C; q is the heat flux density, BT / MM J t is the time of the effect of the heat source, s;

 thermal conductivity coefficient, W / m-deg); specific heat capacity (j / kg-deg); density (kg / m)

processed material. Given a fixed temperature T, for example, the temperature at which sanding defects Td are formed from formula (1),

touch the circle and the workpiece. As the embedment, the microcomputer calculates the current value of the geometrical parameter of the contact zone, for example, the contact spot area S using the well-known formula

S-5 X (L) dL, (3)

about

where (b) is the current (instantaneous length of the contact arc in the direction of the peripheral speed of the workpiece; L is the current (instantaneous) length of the contact arc in the axial section of the shear layer,

L r-arcsinx / f.

For this, the microcomputer calculates the contact arc length - (x) using the formula

35

40

X, s, 7

50

: e / .1 -L / d (x) D (x).,. V d (x) + D (

(four)

ded (x), D (x) are the flowing (instantaneous) diameters of the workpiece and the grinding wheel in cross section x, mm; t (x) is the current (continuous) grinding depth in section X.

And

(five)

t (x) Vr -x2-Y

to where Y r-ti on the first pass and 7 g- i

on any (K + 1) th pass.

After determining o (x) by replacing x rsin, the transition to the function

(L) and calculating the contact area by the formula (5) X

The ti and 2 t values are measured by the sensor.

3 cross feed.

After certain time points d-1: (Lt Dh / Uasev), where Uasev is the speed of the grinding wheel in the direction of movement, the microcomputer 4 determines the increment of the values of the controlled parameter A PX (k is the number of the sampling step) and the geometric of the parameter - contact spot area - D5k and calculates the CALCAT ratio

2

(2)

From the formula (2,) it follows that the permissible value of the specific value of the regulated

1288039

the parameter depends on the thermophysical properties of the material being processed (K s. y) and inversely proportional to the square root of the instantaneous effect of the heat source t.

At the embedding stage, using the power sensor 8 and the axial stir sensor 9, the profile of the circle measures the value of the adjustable parameter P and the axial shifts, respectively. The axial movement of the circle profile is measured from

touch the circle and the workpiece. As the embedment, the microcomputer calculates the current value of the geometrical parameter of the contact zone, for example, the contact spot area S using the well-known formula

S-5 X (L) dL, (3)

about

where (b) is the current (instantaneous length of the contact arc in the direction of the peripheral speed of the workpiece; L is the current (instantaneous) length of the contact arc in the axial section of the shear layer,

L r-arcsinx / f.

For this, the microcomputer calculates the contact arc length - (x) using the formula

: e / .1 -L / d (x) D (x).,. V d (x) + D (

(four)

ded (x), D (x) are the flowing (instantaneous) diameters of the workpiece and the grinding wheel in cross section x, mm; t (x) is the current (continuous) grinding depth in section X.

And

(five)

t (x) Vr -x2-Y

to where Y r-ti on the first pass and 7 g- i

on any (K + 1) th pass.

After determining o (x) by replacing x rsin, the transition to the function

(L) and calculating the contact area by the formula (5) X

The ti and 2 t values are measured by the sensor.

3 cross feed.

After certain time points d-1: (Lt Dh / Uasev), where Uasev is the speed of the grinding wheel in the direction of movement, the microcomputer 4 determines the increment of the values of the controlled parameter A PX (k is the number of the sampling step) and the geometric parameter - contact spot area - D5k and calculates the ratio, which is the specific value of A Ek

adjustable parameter. When decreasing the sampling step, i.e. at Dx-j-dx, the ratio A 4. The micro-computer 4 allocates ABK ub

and fixes the maximum value of the specific value of the adjustable parameter

dP

--7- q, max on the 2-hmax penetration interval (on

FIG. 2 shows half of the insertion interval (xmax), and finds the ratio cjsir

The sensor signal 9 axial mixing of the circle at the time t is recorded current, and the value of the adjustable parameter of the Russian Federation and is determined by

 .

and then the setting value

RF

Qflon Hmm

A micro-method of grinding control with self-tuning modes is introduced into the memory, including changing and fixing the current value of the adjustable power parameter and stabilizing it at a level specified by the setpoint, the value of which is changed depending on the state of the process, characterized in that machining during profile grinding, the adjustable power parameter is fixed after the completion of the plunge stage, and its setpoint value is determined by calculating the product of the fixed value ins parameter and the maximum allowable ratio of specific values of this parameter, and wherein the current

The computer 4 and is maintained with the help of algo-25; the maximum specific value of the regulating rhythms of stabilization of the parameter being controlled is determined at the stage

meter - grinding power - to windows-incision as a ratio of this increment

processing tubs, due to the influence of the parameter on the increment of the geometric

feed drive 7 through a digital-to-analog cutting zone parameter.

converter 6. At the same time the fixed value of the adjustable parameter

RF qcp-Sx max, / g

where qcp is the average specific value of the adjustable parameter (Fig. 2);

Zkmaks-maximum plosh, ady pt of contact.

Claims (1)

Invention Formula The method of grinding control with self-tuning modes, including changing and fixing the current value of the adjustable power parameter and stabilizing it at a level specified by the setpoint, the value of which is changed depending on the state of the process, characterized in that, in order to improve the quality of processing with profile grinding, the adjustable power parameter is fixed after the end of the embedding stage, and its setpoint value is determined by calculating the product of the fixed parameter value by the ratio In winter and maximum unit values of this parameter, and wherein the current maximum specific value (pas.f ..-: / rS ..- / .. / -: -: -l:. ::: -.V j /// AT (// L. W Hmm