JPH02156308A - Numerical controller - Google Patents

Abstract

PURPOSE:To easily operate a machine by correcting the command value in the X-axis direction to cancel the working error due to the deviation in the Y-axis direction between the position of a tool and the center of a main shaft. CONSTITUTION:Only coordinate values of the end point are inputted from a decoding means 2 to an end point coordinate value calculating means 3, and this means 3 outputs its end point coordinate value AGSX(n) in the X-axis direction. Meanwhile, an offset OFSX of the tool diameter is inputted to an ffset data memory 5 and is stored there. A deviation y in the Y-axis direction between the position of the tool and the center of the main shaft is stored in an Y-axis offset memory 6 from a CRT/MDI unit 4. A correction extent calculating means 7 obtains an extent CMPX(n) of difference correction based on the coordinate value AGSX(n), the offset OFSX, and the deviation y by calculation and outputs it to an end point coordinate value correcting means 8. The means 8 adds the extent CMPX(n) of correction to the coordinate value outputted from a decoding means 2 to output a correction command. A pulse distributing means 9 distributes this correction command to an X-axis command pulse and a Z-axis command pulse.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a numerical control device (CNC) for controlling a lathe machine, and in particular to a machining error caused by a deviation in the Y-axis direction between the tool position and the center of the spindle. This invention relates to a numerical control device capable of correcting.

[Conventional technology]

Numerical control equipment (CNC) is coupled with various machine tools,
Widely used. For example, in a machine tool for a lathe, the position of the tool is controlled in the X-axis direction and in the X-axis direction according to a machining program of a numerical control device, and a workpiece attached to a main spindle can be machined.

By the way, in such a lathe machine, if the position of the tool and the center of the main spindle are even slightly deviated in the Y-axis direction, an error will occur in the diameter of the workpiece, making it impossible to perform machining as instructed by the machining program.

For this reason, conventionally, spacers or the like have been used to precisely adjust the mounting position of the tool. Also, as a special machine, Y
By making it possible to control the position in the axial direction, the deviation in the Y-axis direction is corrected.

[Problem to be solved by the invention]

However, it takes a considerable amount of time to adjust the tool position and the center of the spindle so that they do not deviate, and it is often difficult to make more precise adjustments.

Furthermore, making it possible to control the position in the Y-axis direction is costly and requires a complicated structure, leading to a decrease in reliability.

The present invention has been made in view of these points, and it is an object of the present invention to provide a numerical control device that corrects machining errors in the X-axis direction caused by deviations in the Y-axis direction between the tool position and the center of the spindle. purpose.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a numerical control device (CNC) that controls a lathe machine capable of moving tools in the X-axis direction and in the X-axis direction. a setting means for setting a deviation amount in the Y-axis direction between the center of the spindle and the center of the main axis; a correction amount calculation means for calculating a correction amount in the X-axis direction for each block of the machining process based on the deviation amount; coordinate value correction means for adding the amount to a predetermined coordinate value in the X-axis direction of the block instructed by the machining program and outputting a correction command, and eliminating machining errors of the workpiece due to the deviation amount. A numerical control device is provided.

[Effect]

A correction amount is calculated for each block of the machining process based on the amount of deviation in the Y-axis direction, added to a predetermined coordinate value in the X-axis direction, and output as a correction command.

With this correction command, the tool moves further in the X-axis direction by the correction amount than the coordinate values commanded in the machining program, and
Errors in machined shape due to deviation in the axial direction are canceled out.

〔Example〕

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

FIG. 2 is a conceptual diagram of lathe processing using the numerical control device of the present invention. In the figure, reference numeral 20 indicates the position of the tool of the lathe machine when it is ideally installed, and coincides with the center 0 of the main shaft in the Y-axis direction.

However, it is generally difficult to mount the tool so that it is completely aligned with the center O of the spindle in the Y-axis direction, and is usually mounted at a position slightly offset in the Y-axis direction as shown in the tool 20a. The tool 20a processes the workpiece in a controlled manner in the X-axis direction shown in the figure and the unillustrated X-axis direction perpendicular to the plane of the paper.

Now, the position of the tool 20a in the X-axis direction is at the coordinate value X commanded by the machining program, and if machining is performed in this state, the workpiece will change from the machining shape 21 commanded by the machining program, as shown in the machining shape 21a. It is also processed into a shape with a large diameter.

In the numerical control device of the present invention, this machining error is canceled out by correcting the amount of movement of the tool in the X-axis direction.

That is, the tool is moved further in the X-axis direction by a correction amount ΔX than the coordinate values commanded by the machining program, and the radius of the machining shape is set to X.

The correction amount ΔX can be obtained by calculating the following formula (%) (1), where the deviation amount in the Y-axis direction is Δy. However, 5QRT represents the square root. The numerical control device of one embodiment of the present invention performs this calculation for each block of the machining process, adds it to the end point coordinate value in the X-axis direction commanded by the machining program, outputs a correction command, and thereby control the position of

FIG. 1 shows a block diagram of a numerical control device according to an embodiment of the present invention. In the figure, a machining program l created in a predetermined format is decoded by a decoding means 2, and coordinate values at the time of machining are output.

Of these, the end point coordinate value calculation means 3 inputs only the coordinate value of the end point, and outputs the end point coordinate value ABSX (n) in the X-axis direction.

On the other hand, the operator inputs tool diameter offset data to the offset data memory 5 via the CRT/MDr unit 4 and stores it. Further, the deviation amount Δy in the Y-axis direction between the tool position and the center of the spindle is measured in advance, and is stored in the Y-axis deviation amount memory 6 from the CRT/MDI unit 4.
is stored in.

The correction amount calculation means 7 calculates the end point coordinate value ABSX in the X-axis direction.
(n), the offset amount 0FSX in the X-axis direction, and the deviation amount Δy, the following calculation is performed for each block of the machining process.

X (n)=ABSX (n)−0FSXΔx (n
)=X (n)-3QRT (X (n)"-Δ
y2) −・−・−−−−−(3) CMPX
(n) −Δx (n) −Δx(n-1)・
-(4) That is, first, the end point coordinate value X(n) of the tool based on the instruction of the machining program is determined using calculation formula (2). The coordinate value X (n) is the distance from the center of the spindle to the tool when there is no deviation in the Y-axis direction. Next, the correction amount Δx (n) is determined using calculation formula (3). However, 5QRT represents the square root. Then, the difference from the correction amount Δx(n-1) of the previous block is calculated using calculation formula (4) to obtain the difference correction amount CMPX (n), which is output to the end point coordinate value correction means 8.

The end point coordinate value correction means 8 adds the difference correction amount CMPX (n) to the coordinate values output by the decoding means 2 and outputs a correction command. The pulse distribution means 9 distributes this correction command into an X-axis command pulse and an X-axis command pulse, and the servo control means 10 drives the X-axis servo motor lla and the Z-axis servo motor llb.

As a result, the distance between the center of the spindle and the tool at the end point of the block becomes X (n), and the machining error in the end point coordinates is canceled out and the workpiece is machined. In this case, when the machining path commanded by the machining program is linear interpolation, the workpiece is machined by linear interpolation connecting the commanded starting point and the corrected end point with a straight line.

Further, when the machining path is circular interpolation, the workpiece is machined by helical interpolation that connects the commanded starting point and the corrected end point in a spiral.

[Effects of the Invention] As explained above, the numerical control device of the present invention cancels the machining error caused by the deviation in the Y-axis direction between the tool position and the center of the spindle by correcting the command value in the X-axis direction. There is no need to strictly adjust the mounting position of the tool on the machine side, making the machine easier to operate.

Furthermore, since there is no need to control the tool in the Y-axis direction, it is economical and the structure of the machine is simple.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a numerical control device according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram of lathe processing using the numerical control device of the present invention.・−・− Machining program end point coordinate value calculation means Y-axis deviation amount memory ・−Correction amount calculation means End point coordinate value correction means Pulse distribution means Servo control means 6・ −−−−−・ 7− ・・−・・−・8---------・ 9------・ 1 0------1---・ 1 1 a ----・ 1 l b--------・-・ Δy・・-・・・FSX ABSX (n) --------・CMP
X (n) ・−・ 20, 20 a−−−−−・ L21a x −−m−・− ΔX X axis servo motor/X axis servo motor m individual difference offset amount/X axis direction end point coordinate value/difference Correction amount Center of tool machining shape spindle Commanded X-axis coordinate value Correction amount Patent applicant: Fanuc Co., Ltd. Agent Patent attorney Takeshi Hattori Figure 2

Claims (3)

[Claims] (1) In a numerical control device (CNC) that controls a lathe machine that can move a tool in the X-axis direction and the Z-axis direction, a setting that sets the deviation amount in the Y-axis direction between the position of the tool and the center of the spindle. means for calculating a correction amount in the X-axis direction for each block of the machining process based on the deviation amount; A numerical control device comprising: a coordinate value correcting means for adding to a coordinate value and outputting a correction command, and eliminating a machining error of a workpiece caused by the deviation amount. (2) The numerical control device according to claim 1, wherein the predetermined coordinate values are coordinate values of an end point. (3) The above correction amount is calculated using the following formula Δx(n)=X(n)-SQRT(X(n)^2-Δy
^2) However, Δx(n): Correction amount A numerical control device according to claim 1, characterized in that: