JPH0452803A - Control device for machine tool - Google Patents

Abstract

PURPOSE:To simplify the correction of a tool error in the case of job shop type production by storing the existence of tool correction and a correction variable written in a working program and comparing the stored contents with the measuring deviation of the edge of a tool on a tool rest to correct the tool error. CONSTITUTION:The data of a tool error correction absence area, a correction presence area and quantative correction variable D written in a working program of a programmable controller 2 are stored in a storage means 16. Which area stored in the means 16 includes a deviation measured by an edge deviation error measuring means 6 for the tool 3 on the tool rest 10 is decided by a deciding means 20, and at the time of deciding that the deviation is included in the correction existence area, and the tool 3 is corrected only by the quantative correction value of the means 16 by a correcting means 19. Consequently, tool correction existence decision corresponding to product tolerance or quantitative correction value data can be controlled by the working program, and even in the case of job shop type production, tool error correction can be easily and errorlessly executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a machine tool such as a lathe or machining center that performs tool error correction.

[Conventional technology]

If machining is performed on a lathe or the like while the cutting edge of the tool is worn, the machining accuracy will decrease. Therefore, conventionally, in numerically controlled machine tools, the deviation of the position of the cutting edge from the reference position is measured, and the tool is corrected by a quantitative correction amount in accordance with the measurement result. This makes it possible to obtain processing accuracy within the product tolerance.

That is, when the measured deviation amount is within a predetermined correction-free area, no tool correction is performed, and when the measured deviation amount exceeds the correction-free area and is within the correction possible area, tool correction is performed by a quantitative correction amount. If it exceeds the correctable range, an alarm etc. will be issued and processing will be stopped.

The limit data and quantitative correction amount data for each region are given as fixed parameters of the measurement controller or programmable controller.

[Problem to be solved by the invention]

As mentioned above, each limit data and quantitative correction amount data are fixed parameters, so if there are many types of product tolerances for multi-product production, the fixed parameter settings must be changed for each product tolerance. Is it necessary?There is a problem that changing and managing setting values is complicated.

The purpose of this invention is to check the presence or absence of tool correction and the amount of correction.
To provide a control device for a machine tool that can be determined in a machining program and can easily correct tool errors in the case of high-mix, low-volume production.

[Means to solve the problem]

The structure of this invention will be explained based on FIG. 1 corresponding to an embodiment. The control device of this machine tool uses the machining program (
7) A storage means αO is provided for reading and storing each data (A) to (D) of the tool error uncorrected area, corrected area, and quantitative correction amount written in 7). Also, the turret Q
The error measuring means (6) for measuring the cutting edge deviation amount of the tool (3) on l, and the measured deviation amount (support) of this means (6) are located in which area stored in the storage means a[9 A discriminating means (to) is provided for discriminating. With this discrimination means,
A tool correction means α is provided which corrects the tool by the quantitative correction amount when it is determined that the tool is within the correction area.

[For production]

In the machining program (7), data (A) to (D) of tool error uncorrected area, corrected area, and quantitative correction amount are written in accordance with the tolerance of the product to be machined. When executing the machining program (7), each of these data (A) to (D) is read into the storage means αθ, and the measured deviation amount (B) of the error measuring means (6) and the data (A) of each region are read. , (B) and determines in which region it is located by the determining means (to).

If it is determined that the area is in a no-correction area, tool correction will not be performed.
If it is determined that the area is in a correction area, the quantitative correction amount (C)
, Perform tool correction by (D).

〔Example〕

An embodiment of this invention will be described based on FIGS. 111 to 4.

This control device is applied to control a lathe, and includes a numerical control device 1 and a programmable controller 2. An error measuring means 6 is connected to the programmable controller 2 and includes a sensor 4 for detecting the deviation of the cutting edge of the tool 3 from a reference position and an external measurement controller 5. The sensor 4 consists of an actuating transformer, a touch switch, or the like.

The numerical control bag rI11 analyzes the machining program 7 made of NC tape with the arithmetic control section 8, and gives axis drive commands from the servo driver 9 to the servo motors 11 for each axis of the tool rest 10. The sequence control code and the like analyzed by the calculation control section 8 are transferred to the programmable controller 2. Numerical control device! A part of the memory (not shown) of No. 1 is provided with a registration section for a custom macro 14 and an offset data storage section 13 that stores tool offset data, and a correction calculation section 12 that performs tool correction is provided as a calculation control section. It is set at 8.

Machining program 7 includes a second program in addition to the normal program.
As shown in the figure, limit data A for the area without correction, limit data B for the area with correction, and quantitative correction amounts C and D.
is written, and at the same time, the calling instruction 15 of the custom macro 14 is written. In the custom macro 4, reading commands 17 and 18 for reading the limit data A and B and the quantitative correction amounts C and D into the storage means 16 of the programmable controller 2 are registered.

The programmable controller 2 further stores a storage section for the measurement deviation value W of the measurement controller 5, and subprograms for the determination means 2o and transfer means 21 that perform the sequence shown in FIG. The transfer means 21, the offset data storage section 13, and the correction calculation section 12 constitute a tool correction means 19.

Next, the operation of the above configuration will be explained. FIG. 4 shows the relationship between the measured deviation amount W and each region, and is divided into five stages.

The non-correction area a is a range in which the absolute value is A, the small negative correction area b1 is larger than A and less than B, and the large negative correction area c1 is a range of 8 or more. The area b2 with positive/small correction is an area smaller than -8 and greater than or equal to -B, and the area c2 with positive/larger correction is an area less than -B.

In the machining program 7 shown in FIG. 2, the values of A and B are written as uncorrected area limit data A1 and corrected area limit data B, respectively.

In addition, the positive and negative small correction areas b1. In the case of b2, the absolute value of the quantitative correction amount to be corrected by the tool is set as the quantitative correction amount C, and the positive and negative large correction areas c1. In the case of c2, the absolute value of the quantitative correction amount to be corrected for the tool is written as a quantitative correction scale. The values of A and B and the values of C and D are determined as appropriate depending on the tolerance of the product to be machined by the machining program 7.

For example, the values of C and D are 2μ and 10μ, respectively.

When the machining program 7 is executed, the custom macro 14 of the numerical control device 1 reads each limit data A, B of the machining program 7 and the quantitative correction amount C2D into the storage means 16 of the programmable controller 2. When the measurement means 6 performs measurement, the programmable controller 2 compares the limit data A and B with the measurement deviation amount W of the measurement controller 5, and performs the following five steps of determination.

That is, in FIG. 4, the area a without correction, the area b1 with small negative correction, the area b2 with positive and small correction, the area CI with large negative correction,
It is determined to which region of the positive/larger correction region C2 the measured deviation amount W corresponds. In accordance with this determination result, the quantitative correction amounts C and D are set in the offset data storage section 1 of the numerical control device 1.
3, it is transferred in synchronization with the M coat of the waiting command of the machining program 7.

FIG. 3 is a flowchart of this operation. In the case of the non-correction area a, a value of zero is transferred to the offset data storage section 13 (S1, S5). In the case of the area b1 with small negative correction and the area b2 with small positive correction, the quantitative correction amount C of negative and positive values
are transferred to the offset data storage unit 13 (S2.
S3. S6゜S7). In the case of the area C1 with large negative correction and the area c2 with large positive correction, the quantitative correction scales of negative and positive values are transferred to the offset data storage unit 13, respectively (S
4. S8. S9).

During machining, the numerical control device 1 performs tool correction on the feed amount data of the machining program 7 using the value of the offset data storage section 13 in the correction calculation section 12, and outputs it to the servo driver 9.

In this way, the machining program 7 can manage data on the determination of whether or not tool correction is to be performed according to product tolerances and the quantitative correction amounts C and D. Therefore, even in the case of high-mix, low-volume production,
Tool error correction can be performed easily and without errors.

Note that in the above embodiment, the positive and negative large correction areas cl.

In the case of C2, tool compensation is performed, but in the case of the large correction area cl, c2, it is determined that the measured deviation amount W is outside the normal machining range in a positive or negative range, and a notification to that effect is issued. The operation of the lathe may be stopped by doing this.

Further, the correction area may be further divided into a large number of stages, and a quantitative correction amount may be set for each stage.

〔Effect of the invention〕

The machine tool control device of the present invention includes a machining program that includes an area without tool error correction and an area with correction.

and the quantitative correction amount are written in advance, and these area data are compared with the measured deviation amount of the error measuring means to perform the tool correction of the quantitative correction amount.
It is possible to determine the presence or absence of tool correction according to product tolerances and to manage data on quantitative correction amounts using the machining program. Therefore, even in the case of high-mix, low-volume production, tool error correction can be easily performed without causing errors.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, Fig. 2 is an explanatory diagram of its machining program, Fig. 3 is a flowchart of the operation of its judgment means and transfer means, and Fig. 4 is its judgment area. FIG. DESCRIPTION OF SYMBOLS 1... Numerical control device, 2... Programmable controller, 6... Error measuring means, 7... Machining program, 12... Correction calculating section, 13... Offset data storage section, 14... Custom macro, 16... Storage means, 19... Tool correction means, 20... Discrimination means, 2
1.0. Transfer means, a...no correction area, bl...
Area with small negative correction, b2... area with small positive correction, C1
...area with negative large correction, C2...area with positive large correction,
A, B...Limit data, C, D...Quantitative correction amount, W...Measurement deviation amount.

Claims (1)

[Claims] Area without correction of tool errors written in the machining program,
A storage means for reading and storing each data of a correction area and a quantitative correction amount, an error measurement means for measuring a cutting edge deviation amount of a tool on a tool post, and a measured deviation amount of this means is stored in the storage means. A control device for a machine tool, comprising: a discriminating means for discriminating which region the tool is in; and a tool compensating means for correcting the tool by the quantitative correction amount when the discriminating result of the discriminating means determines that the region is in a correction area.