JP2903651B2 - Machine tool control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a machine tool such as a lathe or a machining center for correcting a tool error.

[Conventional technology]

In a lathe or the like, if machining is performed while the cutting edge of the tool is worn or the like, machining accuracy is reduced. Therefore, conventionally, in a numerically controlled machine tool, a deviation of a cutting edge position from a reference position is measured, and a tool correction of a fixed amount of correction is performed according to the measurement result. Thereby, the processing accuracy within the tolerance of the product is obtained.

That is, when the measured deviation amount is within the predetermined correction unnecessary area, tool correction is not performed, and when the measured deviation exceeds the correction unnecessary area and is within the correctable area, the tool correction of the fixed amount of correction is performed.
If it exceeds the correctable area, an alarm or the like is issued to stop the processing.

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

[Problems to be solved by the invention]

As described above, since each limit data and quantitative correction data are fixed parameters, if there are many types of product tolerances for multi-product production, it is necessary to change the setting of the fixed parameters for each product tolerance. Therefore, there is a problem that the operation of changing and managing the set value is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a machine tool control device which can determine the presence or absence of a tool correction and the amount of correction by a machining program and can easily correct a tool error in the case of high-mix low-volume production. is there.

[Means for solving the problem]

The configuration of the present invention will be described based on FIG. 1 corresponding to the embodiment. The control device of the machine tool includes a machining program (7) in which a call command, an area without correction of a tool error, an area with correction, and a fixed amount of correction are written, and a numerical control device (7) for executing the processing program (7). 1), the data of the non-corrected area, the corrected area, and the quantitative correction amount of the machining program (7) are stored in predetermined storage means (16) in response to the calling command of the machining program (7). (14). Also,
An error measuring means (6) for measuring the edge deviation amount of the tool (3) on the tool post (10), and the measured deviation amount (w) of this means (6) is stored in the storage means (16). And a determination means (20) for determining whether or not the area exists. If the determination means (20) determines that the area is within the correction area, the tool correction means (19) performs tool correction by the fixed amount of correction.
Is provided.

(Operation)

In the machining program (7), data (A) to (D) of the non-correction area of the tool error, the area with the correction, and the quantitative correction amount are written according to the tolerance of the product to be processed. When the machining program (7) is executed, these data (A) to (D) are read into the storage means (16), and the measured deviation amount (w) of the error measurement means (6) and the data ( A) and (B) are compared to determine in which area the area is located by the determination means (20).

If it is determined that the area is the area without correction, the tool is not corrected. If it is determined that the area is the area with correction, the tool is corrected by the quantitative correction amounts (C) and (D).

〔Example〕

One embodiment of the present invention will be described with reference to FIGS.

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

The numerical control device 1 analyzes the machining program 7 from the NC tape by the arithmetic and control unit 8, and sends a tool post 10 from the servo driver 9.
Is given to the servo motor 11 of each axis. The sequence control code and the like analyzed by the arithmetic control unit 8 are transferred to the programmable controller 2. A registration unit for a custom macro 14 and an offset data storage unit 13 for storing tool offset data are provided in a part of a memory (not shown) of the numerical controller 1, and a correction operation unit 12 for performing tool correction is provided. It is provided in the arithmetic and control unit 8.

As shown in FIG. 2, limit data A in the non-corrected area, limit data B in the corrected area, and quantitative correction amounts C and D are written in the machining program 7 as shown in FIG. Fourteen read instructions 15 are written. In the custom macro 14, read commands 17, 18 for reading the limit data A, B and the quantitative correction amounts C, 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 20 and the transfer means 21 for performing the sequence shown in FIG. The transfer unit 21, the offset data storage unit 13, and the correction calculation unit 12 constitute a tool correction unit 19.

Next, the operation of the above configuration will be described. FIG. 4 shows the relationship between the measurement deviation amount w and each area, which is divided into five stages. The uncorrected region a has an absolute value in the range of A, the negative / small correction region b1 is a region larger than A and smaller than B, and the negative / large correction region c1 is a region B or larger. Area with correction
b2 is a region smaller than -A and equal to or larger than -B, and the region c2 with positive correction is a region smaller than -B.

In the machining program 7 in FIG. 2, the values of A and B are written as uncorrected area limit data A and corrected area limit data B, respectively. In the case of the positive and negative small correction areas b1 and b2, the absolute value of the quantitative correction amount to be tool-corrected is defined as the quantitative correction amount C, and the positive and negative large correction areas c1 and c2 are set.
In the case of 2, the absolute value of the quantitative correction amount to be tool-corrected is written as the quantitative correction amount D. The values of A and B and the values of C and D are appropriately determined according to the tolerance of a product to be processed by the processing program 7. For example, the values of C and D are 2μ and 10μ, respectively.
And

When the machining program 7 is executed, the limit data A and B and the quantitative correction amounts C and D of the machining program 7 are read into the storage means 16 of the programmable controller 2 by the custom macro 14 of the numerical controller 1. When the measurement is performed by the measuring means 6, 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-stage determination.

That is, in FIG. 4, the measurement deviation amount w corresponds to any of the non-correction area a, the negative small correction area b1, the positive / small correction area b2, the negative large correction area c1, and the positive large correction area c2. Is determined. According to the result of this determination, the quantitative correction amount C,
D is transferred to the offset data storage unit 13 of the numerical controller 1 in synchronization with the M code of the waiting command of the machining program 7.

FIG. 3 is a flowchart of this operation. In the case of the uncorrected area a, a value of zero is transferred to the offset data storage unit 13 (S1, S5). In the case of the negative small correction area b1 and the positive small correction area b2, the negative and positive quantitative correction amounts C are transferred to the offset data storage unit 13 (S2, S3, S6, S
7). In the case of the negative large correction area c1 and the positive large correction area c2, negative and positive quantitative correction amounts D are transferred to the offset data storage unit 13 (S4, S8, S9).

At the time of machining, the numerical control device 1 performs a tool compensation for the feed amount data of the machining program 7 based on the value of the offset data storage unit 13 in the compensation operation unit 12 and outputs the result to the servo driver 9.

In this way, the machining program 7 can manage the data of the quantitative correction amounts C and D and the determination of the presence or absence of the tool correction according to the product tolerance. Therefore, even in the case of high-mix low-volume production, tool error correction can be performed easily and without errors.

In the above embodiment, the tool correction is performed in the positive and negative large correction areas c1 and c2.
In the case of 1, c2, it may be determined that the measured deviation amount w is out of the normal processing range to the positive or negative range, and the operation of the lathe may be stopped by reporting the fact.

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

〔The invention's effect〕

The control device for a machine tool according to the present invention writes the data of the non-correction area of the tool error, the area with the correction, and the quantitative correction amount in the machining program, and compares these area data with the measurement deviation amount of the error measuring means. Since the tool correction of the fixed amount of correction is performed by comparison, the presence / absence of the tool correction according to the product tolerance and the data of the fixed amount of correction can be managed by the machining program. Therefore, there is an effect that tool error correction can be performed easily and without error even in the case of high-mix low-volume production. In addition, when the area with correction is divided into a plurality of areas and a plurality of quantitative correction amounts are provided, more accurate and fine correction can be performed, thereby improving processing accuracy.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the configuration of one embodiment of the present invention, FIG. 2 is an explanatory view of a machining program, FIG. 3 is a flowchart of the operation of the judging means and transfer means, and FIG. FIG. 1 Numerical control device 2 Programmable controller 6 Error measuring means 7 Processing program 12
... Correction operation unit, 13 ... Offset data storage unit, 14 ...
Custom macro, 16 storage means, 19 tool correction means, 20 determination means, 21 transfer means, a area without correction, b1 area with negative / low correction, b2 positive / small correction Existence area, c1 ... area with large negative correction, c2 ... Area with positive large correction, A, B ... limit data, C, D ... quantitative correction amount, w ...
… Measurement deviation

Claims (2)

(57) [Claims] 1. A machining program in which a calling command, an area without correction of a tool error, an area with correction, and a fixed amount of correction are written, and the calling of the machining program provided in a numerical control device for executing the machining program. Means for storing, in response to a command, the data of the uncorrected area, the area with correction, and the quantitative correction amount of the machining program in a predetermined storage means, and an error measurement for measuring an edge deviation amount of the tool on the tool post. Means, a discriminating means for discriminating in which area the measured deviation amount of this means is stored in the storage means, and a tool by the quantitative correction amount when discriminated as an area with correction by the discrimination result of this means. A control device for a machine tool, comprising: a tool correcting means for performing correction. 2. The control device for a machine tool according to claim 1, wherein the area with correction is divided into a plurality of areas, and a plurality of the quantitative correction amounts are provided according to the size of the divided areas.