JPH0780753A - Numerical control method and numerical control system - Google Patents

Abstract

PURPOSE:To enable the working of a workpiece with accuracy at a high speed by giving out information that axial slippage is caused, if it is, when deciding to perform correction working. CONSTITUTION:Each value of error data for the ideal condition of a work piece is compared with each value of allowable errors set in advance by a correction working judging means 15. As a result, only when each value of error data is smaller than each value of allowable errors, it is judged that correction working for the shape of the workpiece is performed. When judgment is made as mentioned above, it is also judged by an axial slippage judging means 11 whether or not the error data is caused by the axial slippage of a working datum in a working machine 1. And when an axis is found by the axial slippage judging means 11 to have slipped, the occurrence of the axial slippage is informed to an operator by an axial slippage informing means, and the working datum is then moved, so that the workpiece is thereby processed for correction by the working machine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control method and a numerical control system for a numerical control device (NC device).

[0002]

2. Description of the Related Art In numerical control machining with an NC device, the shape (actual shape) of a workpiece is measured after the machining is completed.
When an error occurs with respect to a desired shape, a process for correcting the error may be performed. The conventional correction method is
Error data is read from the input unit, target shape data for correction processing is created from the error data, and stored in the target shape data storage unit. Next, a polynomial that approximates the corrected shape is obtained based on the target shape data. Then, a desired program was achieved by creating a command program for the numerical control device (NC device) according to this formula and performing correction processing.

FIG. 3 shows the relationship among the actual shape, the error, the design value shape, the correction amount, and the correction shape. A curve 50 shows a design value shape, and a curve 51 shows an actual shape. The difference between the values of the Z coordinate of the curve 50 and the curve 51 at the points having the same X coordinate is the error 5
It is 3. A correction amount 54 is set on the side opposite to the curve 51 in the Z-axis direction from the curve 50 showing the design value shape by an amount equal to the value of this error, and a curve 52 is defined.

[0004]

In such a conventional correction method, the polynomial approximation of the target shape data is performed in all cases. For example, when the position of the machining origin of the workpiece is misaligned or the diameter of the tool is incorrect, the operator may change the position of the machining origin and the tool diameter. NC program is created. Therefore, it takes time to perform the desired processing.

An object of the present invention is to detect the case where the position of the processing origin of the workpiece is displaced or the case where the diameter of the tool is wrong, and notify the operator of them so that the operation is performed. It is an object of the present invention to provide an NC program creating method and an NC control system, which allows a person to deal with the details finely and can process them accurately at high speed.

[0006]

In order to solve the above problems, according to the present invention, correction shape data for performing correction processing is created from error data about an ideal shape of a workpiece and the correction is performed. In a numerical control system that creates a correction NC program based on shape data, the value of the error data is compared with a value of a predetermined allowable error, and only when the value of the error data is smaller than the allowable error. Correction processing determining means for determining that the shape of the workpiece is to be corrected, and the error data in the processing machine for performing the processing when the correction processing is determined to be performed by the correction processing determining means. There is an axis deviation by means of an axis deviation judging means for judging whether or not it is caused by the deviation of the axis of the machining origin (there is an axis deviation) and the axis deviation judging means. If it is determined, it can be provided with a shaft misalignment notifying means for notifying the occurrence of axis deviation to the outside.

In addition, in the numerical control system that creates the correction shape data for performing the correction processing from the error data about the ideal shape of the workpiece and creates the correction NC program based on the correction shape data, the error data And a predetermined allowable error value are compared, and a correction processing determination is made to determine that the correction processing of the shape of the workpiece is performed only when the value of the error data is smaller than the allowable error. Means and the correction processing determination means determines that the correction processing is to be performed, the error data is generated due to an error in the tool diameter in the processing machine performing the processing (error in tool diameter). A tool radius error determining means for determining whether or not there is a tool radius error determining means, and when the tool radius error determining means determines that there is a tool radius error, the tool radius error is notified to the outside. It may be provided with a tool 径誤 Ri notifying means.

[0008]

According to the present invention, when the position of the processing origin of the workpiece is displaced or the diameter of the tool is incorrect, the operator is notified of these and the position of the processing origin or The tool diameter can be changed. Corrective machining is performed after changing the machining origin position and tool diameter.

In this correction processing, if the position of the processing origin is shifted, the NC program is used. If the tool diameter is incorrect, a correction NC program is created and this correction NC program is used.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a block diagram of the configuration of an embodiment of a numerical control system to which the numerical control method of the present invention is applied. FIG. 10 shows an example of the hardware system configuration of the NC program creation device (numerical control device) 40 used in this embodiment.

In FIG. 2, the present embodiment shows a workpiece 50.
Processing machine 1 for processing to N, and N connected to this
An NC machining program is created by referring to the C controller 30, the shape measuring device 100 provided in the processing machine 1 for measuring the shape of the workpiece 50, and the shape measurement result.
And a program creation device 40.

The shape measuring apparatus 100 is provided so as to be movable relative to the work piece 50, and the measurement terminal 70 for detecting the relative positional relationship of the work piece 50, and this measurement with reference to a predetermined origin. It is composed of a position measuring device 90 for measuring the position of the terminal 70, and an information processing device 10 for processing measurement data to obtain a shape measurement value.

Measuring terminal 70 and position measuring device (length measuring device 91)
90 is mounted on the processing machine 1 as shown in FIG.

The processing machine 1 includes a workpiece 50, a workpiece drive mechanism 87 for holding and rotating the workpiece 50, a stage 81 on which the drive mechanism 87 is mounted, and a support base for movably supporting the stage 81. 82, a stage drive device 83 for moving the stage 81 by a necessary amount, and a stage 8 for supporting the tool base 51 and the measurement terminal 70.
4, a support base 85 for movably supporting the stage 84, and a stage drive device 86 for moving the stage 84 by a necessary amount.

The NC controller 30 operates the stage drive devices 83, 8 of the processing machine 1 according to the processing program.
6 and the work drive mechanism 87. Also,
When performing the shape measurement, the operations of the stage driving devices 83 and 86 are controlled according to the instruction from the NC program creating device 40.

The NC program creating device 40 creates a control program for the NC controller 30 and various parameters necessary for machining, measurement, etc., and outputs them to the shape measuring information from the information processing device 10. Import, create a correction program, parameters, etc.,
Send to the NC controller 30.

As shown in FIG. 10, the NC program creating device 40 includes a central processing unit (CPU) 401 and a C
A first memory (ROM) 402 for storing a program of the PU 401 and each fixed data, and a second memory (RAM) for storing data read from the outside, a calculation result, and the like.
403, an interface 404 for exchanging data with the NC controller 30, and an NC program creating device interface 40 for connecting with the information processing device 10.
5, an input device 406, and a display device 407.

Although not shown, the information processing apparatus 10
A shape measuring means for receiving the measurement command sent from the NC program creating device 40 and taking in an output signal from the measuring terminal 70 to measure the shape of the workpiece, and a shape measured value for storing the measured value at each measuring point. It has a storage means and a shape measurement value output section for outputting the shape measurement value to the NC program creating device 40.

The measuring terminal 70 is composed of, for example, a differential transformer type measuring probe, and outputs a signal indicating a displacement amount of ± from a predetermined reference point, for example, a center position.
In this embodiment, the measuring terminal 70 is of a contact type, but
It may be a non-contact type.

As the position measuring device 90, an optical length measuring instrument 91 is used in this embodiment. That is, a mirror 94 is attached to the stage 81 and a mirror 96 is attached to the stage 84, and light rays are incident on the former via the mirrors 92 and 93 and on the latter via the mirror 95, respectively. The length measuring instrument 91 of this embodiment is provided with a mirror 94.
And 96 displacements are optically measured, and coordinate data based on a predetermined origin is output. In the present embodiment, the equipment provided in the processing machine 1 is shared, but it may be provided independently.

Next, FIG. 1 shows a functional block diagram of the NC program creating apparatus 40 of the present invention.

In FIG. 1, the operation input display output unit 21
Inputs an operation instruction from the operator 110, and outputs an instruction such as a message to the operator 110. The design value machining shape data input unit 16 inputs and stores data regarding an ideal machining shape. Further, it is used by the corrected machining shape data creation unit 13 described later. The design value NC program creation unit 17 creates an NC program based on the ideal machining shape input by the design value machining shape data input unit 16. The NC program storage unit 18 stores the design value NC program creation unit 17 or a correction N described later.
The program created by the C program creating unit 14 is stored. The NC program analysis unit 19 analyzes the program stored in the NC program storage unit 18. The NC program execution unit 20 executes the program analyzed by the NC program analysis unit 19 to process the workpiece with a processing machine.

The shape measuring apparatus 100 measures the shape of the machined surface of the machined workpiece, calculates a shape error from the measurement result, and transmits the calculated error to the NC program execution unit 20. The NC program execution unit 20 transmits the transmitted error to the correction processing presence / absence determination unit 15. The correction processing presence / absence determining unit 15 compares the error value with a predetermined allowable error value to determine whether the shape error is within the allowable error. If it is determined to be within the allowable error, an instruction to end the processing is generated. When it is determined that the shape error is not within the allowable error, the shape error is compared with a predetermined threshold value to determine whether or not the shape error is within the correction processable range.

Presence / absence determination unit 11 for creating a corrected NC program
If the correction processing presence / absence determining unit 15 determines that the correction processing is within the range in which the correction processing can be performed, a correction NC program is created and correction processing is performed, or a correction NC program is created by shifting the axis of the processing origin. Whether or not the correction processing is performed is judged by predicting each effect.

Presence / absence determination unit 12 of correction machining shape data creation
Means for determining the presence / absence of creation of the correction NC program
However, when it is determined that the correction NC program is to be created, the correction NC program is created after obtaining the corrected machining shape data obtained by adding the correction to the machining shape data, or only the machining conditions are changed and the corrected machining shape data is not obtained. Corrected by NC
Judge whether to create a program by predicting each effect.

The corrected machining shape data creating unit 13 corrects the machining based on the design value machining shape data input by the design value machining shape data input unit 16 and the shape error calculated by the shape measuring apparatus 100. Create the data. The correction NC program creation unit 14 creates a correction NC program from the correction processed data and stores it in the NC program storage unit 18. The corrected NC program is analyzed by the NC program analysis unit 19 and executed by the NC program execution unit 20.

Next, the operation of the NC program creating device 40 according to the present invention will be described with reference to FIGS. 1 and 9.

First, the operator inputs the design value processed shape data from the operation input display output unit 21. This data is input to the design value processed shape data input unit 16. Next, the design value NC program is created by the design value NC program creating unit 17 using the design value shape data. The created NC program is stored in the NC program storage unit 18, then analyzed by the NC program analysis unit 19 and executed by the NC program execution unit 20 to machine the workpiece in the machining machine 1 ( Step 910).

After processing, the shape measuring device 10
With 0, the shape error, which is the difference between the design value shape (ideal shape) of the workpiece and the actual shape, is measured. This shape error is
Through the NC program execution unit, the operation input display output unit 2
1 is displayed (step 920).

Next, the NC program execution unit 20
The shape error is transmitted to the correction processing presence / absence determining unit 15. The correction processing presence / absence determination unit 15 determines whether or not the shape error is within a predetermined allowable range (step 9).
30). If it is determined to be within the allowable range, the processing ends. If it is judged that it is not within the allowable range,
The shape error is compared with a predetermined threshold value to determine whether or not the shape error is within a correction processable range (step 940).

FIG. 4 shows the case where the shape error is within the allowable error range, and the correction processing presence / absence determining unit 15 determines that the correction processing is not necessary.

In FIG. 5, since the shape error changes abnormally in the range S, the correction processing presence / absence determining unit 15 determines that the correction cannot be performed even if the correction processing is performed.

If it is determined that the correction is not within the allowable processing range, it is determined that the product is defective and the processing is terminated. When it is determined that the correction processing is within the allowable range, the correction NC program creation presence / absence determining unit 11
A shape error in the case where the position of the processing origin of the workpiece is shifted and processed is calculated, and it is determined whether or not the difference between this shape error and the actual shape error is larger than a predetermined value (step 950). ).

If it is determined that if the shape error is smaller than a predetermined value if the machining origin is displaced and machining is performed, a message for instructing the operator to move the machining origin is displayed as an operation input display output. It is displayed on the section 21. When the processing origin is moved by the operator (step 960), the correction processing is performed in the processing machine 1 (step 100).
0), and returns to step 920.

FIG. 6 shows a case where the axis of the processing origin is displaced. Presence / absence determination unit 11 for creating a corrected NC program
Therefore, it is determined that it is not necessary to create the corrected NC program. Simultaneously with the judgment, the shift amount of the machining origin axis is also calculated. In that case, the machining origin is shifted by the shift amount calculated and the NC program is re-machined with the same one as the immediately preceding one.

Calculation of the shift amount of the axis of the processing origin will be described with reference to FIG. In FIG. 11, the curve 11
The curve 0 represents the shape of the design value, and the curve 120 is the shape calculated by shifting the machining origin. Also, curve 13
Let 0 be the actually measured shape. In the curve 120, the variable i
The reason why is attached is that a curve in which the machining origin is shifted by a plurality of types of shift amounts is conceivable. When the machining origin is shifted in this way, the shape error Eik is calculated by the following equation.

[0038]

[Equation 1]

The actually measured shape error Fk is calculated by the following equation.

[0040]

[Equation 2]

Where

[0042]

[Equation 3]

Then, this Si is calculated by gradually changing the deviation amount within a possible deviation range of the processing origin, and k from 0 to N of (Eik-Fk) when Si becomes the smallest. If the maximum value between the two is within the predetermined allowable value, the machining origin is shifted to perform the compensation machining.

In step 950, when it is determined that the difference between the shape error when the position of the processing origin of the workpiece is shifted and the actual shape error is larger than a predetermined value, the correction processing is performed. The shape data creation presence / absence determining unit 12 calculates a shape error when machining is performed by changing the setting of the tool diameter, and the difference between this shape error and the actual shape error is larger than a predetermined allowable error. It is determined whether or not (step 970).

Calculation of the change amount of the tool diameter setting will be described with reference to FIG. In FIG. 12, the curve 15
The curve 0 represents the shape of the design value, and the curve 160 is the shape calculated by changing the tool diameter. Also, the curve 170
Is the actually measured shape. The variable i is attached to the curve 160 because a curve in which the tool diameter is changed by a plurality of types of change amounts is conceivable. When the tool diameter is changed in this way, the shape error Eik is calculated by the following equation.

[0046]

[Equation 1]

The actually measured shape error Fk is calculated by the following equation.

[0048]

[Equation 2]

Where

[0050]

[Equation 3]

Then, this Si is calculated by gradually changing the amount of change within the range in which the tool diameter can be changed, and k of 0 to N of (Eik-Fk) when Si becomes the smallest.
If the maximum value up to is within the specified tolerance, correct the machining by changing the tool diameter.

If it is determined in step 970 that it is smaller, a message instructing the operator to change the tool diameter is displayed on the operation input display output unit 21. When the operator changes the tool diameter, the tool diameter is changed to create a correction NC program (step 980), correction processing is performed in the processing machine 1 (step 1000), and the process returns to step 920.

FIG. 7 shows that when the processing conditions are bad,
This is an example when the tool diameter has an error between the instructed one and the actual one. The correction machining shape data creation presence / absence determining unit 12 determines to create the correction NC program without changing the machining conditions and obtaining the corrected machining shape data. At the same time as the judgment, the correction value of the tool diameter is calculated. In that case, the corrected NC program is created by the corrected NC program creating unit 14 using the corrected tool diameter calculated.

If it is determined to be large in step 970, the correction machining shape data is created to create the correction NC program (step 990), and the correction machining is performed in the processing machine 1 (step 1000).
Return to 20.

FIG. 8 shows a case where the correction cannot be performed even if the axis of the processing origin is shifted or the processing conditions are changed. The correction processing shape data creation presence / absence determining unit 12 determines that the correction can be performed by creating the correction processing shape data and performing the correction processing. In that case, the corrected machining shape data creation unit 13
Thus, the corrected machining shape data is created, and the corrected NC program creation unit 14 creates the corrected NC program.

[0056]

According to the present invention, when the position of the processing origin of the workpiece is misaligned or the diameter of the tool is wrong, these are detected and the operator is notified of them. Thus, it is possible to provide a numerical control method and a numerical control system that allow an operator to handle the details finely and to perform high-speed and accurate machining.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an NC program creating device 40 according to the present invention.

FIG. 2 is a block diagram showing the configuration of a numerical control system to which an embodiment of the present invention is applied.

FIG. 3 is an explanatory diagram showing a relationship among an actual shape, an error, a design value shape, a correction amount, and a correction shape.

FIG. 4 is an explanatory diagram showing a specific example of a shape error.

FIG. 5 is an explanatory diagram showing a specific example of a shape error.

FIG. 6 is an explanatory diagram showing a specific example of a shape error.

FIG. 7 is an explanatory diagram showing a specific example of a shape error.

FIG. 8 is an explanatory diagram showing a specific example of a shape error.

FIG. 9 is a flowchart showing an operation procedure of the NC program creating device 40 of the present invention.

FIG. 10 is a block diagram showing an example of a hardware system configuration of an NC program creating device 40 used in this embodiment.

FIG. 11 is an explanatory diagram regarding a shift amount of an axis of a processing origin.

FIG. 12 is an explanatory diagram related to a change amount of a tool diameter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing machine, 11 ... Correction NC program creation presence / absence determination unit, 12 ... Correction machining shape data creation presence / absence determination unit, 13
... correction machining shape data creation unit, 14 ... correction NC program creation unit, 15 ... correction machining presence / absence judgment unit, 16 design value machining shape data input unit, 17 ... design value NC program creation unit, 18 ... NC program storage unit, 19 ... NC program analysis unit, 20 ... NC program execution unit, 40 ... NC program creation device, 100 ... Shape measurement device.

Claims (8)

[Claims] 1. A numerical control method for creating corrected shape data for performing correction processing from error data about an ideal shape of a workpiece and creating a correction NC program based on the corrected shape data. Is compared with a predetermined allowable error value, and only when the value of the error data is smaller than the allowable error, it is determined to correct the shape of the workpiece, and the correction is performed. When it is determined that machining is to be performed, the error data is generated because the axis of the machining origin in the machining machine that performs the machining is deviated (axis misalignment).
It is determined whether or not there is a shaft misalignment, and when it is judged that the shaft misalignment is present, the occurrence of the shaft misalignment is externally notified. 2. The method according to claim 1, wherein when it is determined that there is no axis deviation, it is determined whether or not the error data is an error in a tool diameter in a processing machine that performs the processing (a tool diameter error is present). Then, when it is determined that the tool diameter is incorrect, a numerical control method is characterized in that the occurrence of the error in the tool diameter is notified to the outside. 3. A numerical control system for creating corrected shape data for performing correction processing from error data on an ideal shape of a workpiece and creating a correction NC program based on the corrected shape data, wherein the error data And a predetermined allowable error value are compared, and a correction processing determination is made to determine that the correction processing of the shape of the workpiece is performed only when the value of the error data is smaller than the allowable error. Means and the correction processing determination means determines that the correction processing is to be performed, the error data is generated due to the deviation of the axis of the processing origin in the processing machine that performs the processing ( Axis deviation determination means for determining whether or not there is an axis deviation, and if the axis deviation determination means determines that there is an axis deviation, an axis deviation notification that notifies the outside of the occurrence of the axis deviation. Numerical control system comprising: the means. 4. The error data according to claim 1, wherein the error data is an error of a tool diameter in a processing machine that performs the processing when the axis deviation determining means determines that there is no axis deviation (error of tool diameter). ) Tool diameter error determining means for determining whether or not the tool diameter is incorrect, and a tool diameter for notifying the occurrence of an error in the tool diameter to the outside when the tool diameter error determining means determines that the tool diameter is incorrect. A numerical control system comprising: an error notifying means. 5. The axis deviation determining means determines the degree of axis deviation of the machining origin, and the axis deviation notifying means externally notifies the degree of axis deviation. Numerical control system. 6. The tool radius error determining means according to claim 2, wherein the tool radius error determining means determines the degree of error of the tool radius, and the tool radius error notifying means notifies the degree of the tool radius error to the outside. Characteristic numerical control system. 7. The correction NC program according to claim 4, wherein, when the tool radius error determining means determines that the tool radius is incorrect, the tool radius is changed based on the degree of the tool radius error. And a means for creating a corrected machining shape data when the tool diameter error determination means determines that the tool diameter is not an error, and a corrected NC program based on the corrected machining shape data. A numerical control system comprising: 8. A numerical control system for creating corrected shape data for performing correction processing from error data about an ideal shape of a workpiece and creating a correction NC program based on the corrected shape data, wherein the error data And a predetermined allowable error value are compared, and a correction processing determination is made to determine that the correction processing of the shape of the workpiece is performed only when the value of the error data is smaller than the allowable error. Means and the correction processing determination means determines that the correction processing is to be performed, the error data is generated due to an error in the tool diameter in the processing machine that performs the processing (error in tool diameter). Tool diameter error determining means for determining whether or not there is a tool diameter error, and a tool for notifying the outside of the tool diameter error when the tool diameter error determining means determines that there is a tool diameter error Numerical control system comprising: an error notifying means.