JPH048473A - Chopping control system - Google Patents

Abstract

PURPOSE:To compensate a chopping distance easily in a short time by storing a compensation value of chopping motion in a compensating table, compensating the chopping distance, and constituting it so as to generate a chopping distance command. CONSTITUTION:A chopping compensation value is premeasured and tabularized, and it is stored in a compensating table 16 in advance. Next, when a chopping velocity is commanded, the chopping compensation value conformed to the chopping velocity is read out of the compensating table 1, adding it to a chopping distance by an adder 18, finding a chopping distance command value, through which chopping motion of a grinding tool is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a chopping control method for controlling the chopping operation of a grinding tool in a grinder or the like, and particularly to a chopping control method for easily obtaining a chopping correction value.

[Conventional technology]

In a jig grinder or the like, a chopping operation is performed in which the side surface of a workpiece is ground by moving the Z axis up and down and moving the X and Y axes accordingly. The movement of the two axes is constant in the vertical direction, and the upper end point is called the top dead center, and the lower end point is called the bottom dead center.

In the past, these top dead center and bottom dead center were set using limit switches, etc., but in recent jig grinding machines equipped with numerical control devices, they can now be set using commands, parameters, etc. in the machine program. There is.

On the other hand, when chopping the Z-axis at high speed, the actual tool will not be able to reach the top dead center or bottom dead center due to delays during acceleration/deceleration, servo system follow-up delays, etc., and the grinding range will be shorter than the command value. , the commanded range cannot be ground.

To solve this problem, the deviation from the command position at the time when the chopping operation reaches a steady state is calculated as a chopping correction value. That is, a chopping operation is performed, first an appropriate correction value is given, and then a chopping operation is performed to obtain a new correction value. This process was repeated to find the optimal correction value.

[Problem to be solved by the invention]

However, with the above method, it takes a considerable amount of time to obtain an appropriate correction value. On the other hand, the optimum correction value is approximately a fixed value for each machine depending on the chopping speed.

The present invention has been made in view of these points, and it is an object of the present invention to provide a chopping control method in which chopping correction values are made into a table and the chopping correction values can be found in a short time.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a chopping distance calculation means for calculating the chopping distance from the commanded top dead center and bottom dead center in a chopping control method for controlling the chopping operation of a grinding tool in a grinding machine or the like. ,
A chopping control method comprising: a correction table storing chopping correction values corresponding to chopping speeds; and an adder that adds the chopping distance and the chopping correction value to calculate a chopping distance command value. provided.

[Effect]

The chopping correction value is measured in advance, tabulated, and stored in a correction table. When a chopping speed is commanded, a chopping correction value corresponding to the chopping speed is read from the correction table, added to the chopping distance to obtain a chopping distance command value, and the chopping operation of the grinding tool is performed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 is an indispensable diagram for explaining the chopping operation.

The tool shaft 1 moves up and down in the Z-axis direction, causing the grinding tool 2 to move up and down. The grinding tool 2 rotates in the direction shown by arrow A, advances in the direction shown by arrow B, and grinds the side surface 3a of the workpiece 3.

In the initial position of the grinding tool 2, R is the reference point, 0 is the top dead center and 2 is the bottom dead center. These Canadian programs are commanded as follows.

G81. I Z--Q--Fc--; (a)G
OI X--Y--F--; (b) In the program (a) above, rG81. IJ is a chopping command, 2 is a bottom dead center, 0 is a top dead center, and Fc is a chopping speed command.

The program (b) moves the grinding tool 2 on the XY plane under the chopping conditions instructed in (a). X is the amount of movement on the X axis, Y is the amount of movement on the Y axis, and F is the combined speed of the X and Y axes.

Next, an outline of a ladle for implementing the chopping control method of the present invention will be explained. FIG. 4 is a diagram showing the flow for calculating the chopping distance command value of the present invention. The chopping distance 4 is obtained from the top dead center 0 and bottom dead center Z of the Canadian program as A=Q-Z. If a chopping operation is performed with this value, the actual chopping distance will be smaller than β due to delays in acceleration/deceleration and follow-up delays in the servo system. Therefore, the correction value Δ corresponding to the chopping speed is determined in advance! is prepared as a correction table, read out the correction value Δ1 from the correction table, add it to the program command value, and add the chopping distance command value 5 (β+2
Find △l). If the chopping operation is performed with this chopping distance command value 5, the actual chopping distance 6 (β) of the grinding tool 2 will match the program command value 4 (β).

FIG. 1 is a block diagram of the chopping control method of the present invention. Canada program directive, G81. IZ
--Q --Fc --; When (a) is done, top dead center Ω is placed in register 11, bottom dead center 2 is placed in register 12,
The chopping speed command Fc is stored in the register 13.

Chopping distance! is the chopping distance calculation means 15
It can be calculated using the following formula.

f=Q-Z On the other hand, the correction value calculation means 17 reads out the correction value Δp corresponding to the chopping speed Fc, and sends 2Δl, which is twice the correction value, to the adder 18. The adder 18 calculates the actual chopping command value (β+2△
l) is calculated and sent to the axis control circuit 21. Axis control circuit 21
outputs a speed command to the servo amplifier 31, and the servo amplifier 31 drives the servo motor 41 to cause the grinding tool 2 to perform a chopping operation.

On the other hand, according to the X-axis and Y-axis commands Go 1X---Y---F---; (b), the interpolation means 19 outputs the X-axis and Y-axis interpolation pulses to the axis control circuits 22 and 23, respectively. and axis control circuit 22
．． 23 gives a speed command value to the servo amplifier 32 and 33,
Servo amplifiers 32.33 drive servo motors 42.43. Servo motor 42 is the X-axis piece, servo motor 43
is a servo motor around the Y axis.

FIG. 2 is a diagram showing an example of a correction table. The correction table has data number 16a, chopping speed 16b (Fc
), correction value 16c (ΔI).In other words, in the example of data number No. 1, the chopping speed (Fc) is 1
0 m/rr+in indicates that the correction value (Δ1) is 20 mm.

Note that if there is no data corresponding to the commanded chopping speed Fc, calculation is made from the previous and subsequent data. That is, when the chopping speed is 16 m/min, the correction value calculation means 17 calculates as follows, assuming that the correction value changes linearly.

20+ (40-20)x ((16-10)/ (2
0-10))=32 The first term 20 is the correction value when the chopping speed is 10 m/min, and (40-20) is the chopping speed 1
This is the difference between the chopping correction values of 0 m/min and 20 m/min. ((16-10)/ (20
-10)) is a coefficient for linearly distributing this difference.

FIG. 5 is a flowchart showing the flow of the chopping control method of the present invention. In the figure, the number following S indicates the step number.

[S1] Read top dead center Q1 bottom dead center Z1 chopping speed Fc from the Canadian program.

[S2] The chopping distance calculation means 15 calculates the chopping distance l.

A=Q-2 [S3] Refer to the correction table 16, and if there is data corresponding to the chopping speed, proceed to S5, otherwise proceed to S4.

[S4] Since there is no corresponding data in the correction table 16, a necessary correction value Δp is calculated from the previous and subsequent data.

[S5] The adder 18 adds a correction value Δl to the chopping distance β.
is added and output to the axis control circuit 21.

[S6] Perform chopping operation using this value.

In the above explanation, the correction value of the correction table depends only on the chopping speed, but in reality it also depends on the chopping distance. Therefore, it is also possible to create a correction table in which the correction value is determined based on the chopping speed and the chopping distance.

That is, if the chopping distance does not change much, the correction table can be constructed from data consisting only of the chopping speed.

When the chopping distance changes significantly, a correction table having data corresponding to the chopping speed and the chopping distance is effective.

〔Effect of the invention〕

As explained above, in the present invention, the correction value of the chopping operation is stored in the correction table, the chopping distance is corrected, and the chopping distance command is generated. Therefore, the chopping distance can be corrected easily and in a short time. It will be held in

[Brief explanation of drawings]

Fig. 1 is a block diagram of the chopping control method of the present invention, Fig. 2 is a diagram showing an example of a correction table, Fig. 3 is a diagram for explaining the chopping operation, and Fig. 4 is a diagram showing the chopping command value of the present invention. FIG. 5 is a flowchart showing the flow of the chopping control method of the present invention. a Grinding tool workpiece processing surface Chopping distance calculation means Correction table Correction value calculation means Adder Interpolation means Patent applicant: Fanuc Co., Ltd. Agent Patent attorney Takeshi Hattori Figure 4

Claims (3)

[Claims] (1) In a chopping control method that controls the chopping operation of a grinding tool in a grinding machine, etc., there is a chopping distance calculation means that calculates a chopping distance from the commanded top dead center and bottom dead center, and a chopping correction value that corresponds to the chopping speed. A chopping control method comprising: a correction table storing the chopping distance; and an adder that adds the chopping distance and the chopping correction value to calculate a chopping distance command value. (2) comprising a correction value calculation means for calculating a chopping correction value corresponding to the chopping speed from chopping correction values corresponding to chopping speeds before and after the chopping speed when the chopping speed is not in the correction table; The chopping control method according to claim 1, characterized in that: (3) The chopping control method according to claim 1, wherein the correction table stores correction values corresponding to chopping speed and chopping distance.