JPH05158515A - Offset correcting method for nc cutting machine with tool turning shaft - Google Patents

Abstract

PURPOSE:To shorten a cycle time by eliminating a waiting operation in the course of working for an offset operation. CONSTITUTION:Before working is started, an offset amount of a blade edge position based on a turning angle of a tool turning shaft is calculated in advance, based on the offset amount set value of a reference angle (S2). Even in the case of the same tool, an offset number is put thereon at every turning angle, and the offset amount being a result of operation is transferred to the corresponding part of the offset number in an execution storage area (S3). At the time of working, a tool position is corrected by reading in the corresponding offset amount by the offset number at the time of indexing the tool (S4), (S5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset correcting method for an NC cutting machine having a tool turning axis such as a turning type milling head.

[0002]

2. Description of the Related Art Conventionally, there is a cutting machine equipped with a milling head, such as a turning center, in which the milling head can be swung and a tapered surface or an oblique hole can be machined. Various tools are interchangeably attached to the milling head by an automatic tool changer (ATC) device. Generally, each tool has a different cutting edge position, and therefore an offset amount is set for each tool, and the tool position is corrected during machining. When the turning angle of the tool is changed, the offset amount also changes according to the tool turning angle. Therefore, it is necessary to calculate the data of the offset amount according to the turning angle. Conventionally, this calculation is performed every time the automatic tool is changed as follows.

That is, as shown in FIG. 4, in the preparatory stage before processing, only the offset amount at the reference angle is set in a predetermined storage area of the NC device (R1) and processing is started. At the time of machining, every time tool exchange or tool turning by T code is executed (R2), the offset amount data of the storage area is transferred to the work area (R3), and correction calculation is performed according to the tool angle (R4). After the calculation result is transferred to the execution area (R5), the tool position is corrected (R6).

[0004]

As described above, conventionally, the calculation of the offset amount data and the data transfer associated with the change of the turning angle are performed every time the T code is executed. This has been a time-consuming factor, and has been a cause of increasing the processing cycle time.

An object of the present invention is to provide an offset compensating method for an NC cutting machine with a tool swivel axis, which has no waiting operation during machining for offset calculation and can shorten cycle time.

[0006]

The method of the present invention will be described with reference to FIG. 3 corresponding to an embodiment. In this offset correction method, before starting machining, the offset amount of the blade edge position based on the turning angle of the tool turning axis is calculated in advance based on the offset amount setting value of the reference angle (S2), and each turning angle of each tool is calculated. Is stored in a predetermined storage area (S3). At the time of machining, at the time of tool indexing (S4), the corresponding offset amount in the storage area is read to correct the tool position (S5).

[0007]

According to this method, the offset amount is converted in advance with respect to the change of the turning angle, and even for the same tool, one offset amount storage area is assigned to one turning angle. Therefore, it is not necessary to perform the correction calculation during machining, and the waiting time of the machine for the calculation is eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view of a turning center which is an example of an NC cutting machine to which the method of the present invention is applied.
This turning center consists of a fixed spindle 1 and a spindle 1.
And a sub-spindle 2 which is movable in two axial directions facing each other,
The turret 3, the milling head 4, and the tool changing device 5 are provided, and the offset correction method is applied to the milling head 4. The work held on the main spindle 1 can be processed by any of the tools of the turret 3 and the milling head 4, and can be carried by the sub-spindle 2 while being held. The tool exchanging device 5 exchanges the tool of the milling head 4 with an arbitrary tool of the tool magazine 7 by the exchanging arm 6.

The milling head 4 can be mounted with either a rotary tool or a fixed tool, is installed on a slanted bed 8 via a movable base 9 and a swivel base 10, and is mounted in two axes X and Z directions. Feeding and swiveling about a swivel axis B perpendicular to both axes X and Z are possible. The feed of each axis X and Z is performed by a feed screw (not shown) by the X-axis servo motor 11 and the Z-axis servo motor 12 of FIG. 1, and the turning around the turning axis B is performed by the turning drive device 13. ..

FIG. 1 is a functional block diagram of the NC device.
The NC device 14 is a means for executing the machining program 15 by the machining program executing means 16 to control the entire turning center. The NC device 14 includes a milling head 4
The following means are provided as means for performing the offset amount conversion for the turning of the vehicle in advance.

That is, the offset calculation means 17 composed of a macro program, the reference angle offset storage means 18 and the offset number / turning angle storage means 19 for storing the input data thereof, and the respective turning angle offset storage means 20 for storing the calculation result. And are provided. Each turning angle offset storage means 20 is set as an execution area that is actually referred to during machining, and even for the same tool, one storage area and one area for one turning angle (B-axis angle) are set. The indicated offset number _AT is assigned.

Next, the offset correction method will be described with reference to the flowchart of FIG. First, the offset amount at the reference angle of each tool mounted on the milling head 4 is set in the reference angle offset storage means 18 in the working storage area (S
1), offset calculation means 1 comprising a macro program
7 is executed by MDI (manual input operation) from the input device 21. For example, it is executed by inputting the data in the format of "G101A5, B-45". “G101” in the above format is offset calculation means 17
"A5" is the offset number that is the transfer destination of the calculation result, and "B-45" is the tool angle is 4
It is a code indicating that the angle is 5 degrees.

In this way, by inputting each data, the offset calculation means 17 performs correction calculation of the offset amount of the cutting edge position according to the turning angle of the tool (S2),
The calculation result is transferred to the storage area searched by the offset number (A _T = A5) in each turning angle offset storage means 20 (S3).

The correction calculation according to the turning angle is performed according to the following calculation formula in this embodiment. In _{x C '= x C × sin} (α-π) -z C × cos (α) z C' = x C × cos (α) -x C × sin (α) above equation, x _C, z _C is The reference angle offset amount of each axis, α is the turning angle of the tool.

The calculation result x _C ′, z _C ′ of the offset amount of each axis calculated in this way is the offset number A _T
Are transferred to the x _T and z _T parts which are the offset amount storage parts of the respective axes. By such an operation, the offset amount is calculated and stored for each turning angle for each tool.

On the other hand, the T code (tool command code) 22 in the machining program 15 describes the type of tool, the turning angle α, and the offset number _AT , so that if the angle changes, it is treated as another tool. , Another T code 22 is described for each turning angle.

In the process of executing the machining program 15 by the machining program executing means 16, each time the T code 22 is executed to change the tool or index the angle of the tool (S).
4), the offset number _AT specified in the T code 22
The offset amounts of the axes X and Z are corrected based on the storage data of the turning angle offset storage means 20 corresponding to (S5).

According to this offset correction method, the offset amount of the cutting edge position associated with the change of the turning angle of the tool is calculated in advance and stored in a predetermined storage unit in the execution area, so that the offset is generated during machining. It is not necessary to calculate the quantity, and there is no waiting operation of the machine due to the calculation time. Therefore, the cycle time is shortened. Since the correction calculation is performed in advance, there are many setup items and it is unsuitable for a small lot. However, when processing a lot to some extent, the effect of shortening the processing time is greater than the increase in the setup time.

Further, according to this method, since the macro program for the correction calculation is not executed by the T code 22, it is not necessary to describe the T code 22 as a single line in the machining program 15, and a special program is not required. Also, the tool magazine 7 can be indexed while the machine is moving.

In the above embodiment, the offset number A _T is described in the T code 22, but the T code 2
2 does not describe the offset number _AT , but prepares a table for selecting the offset number _AT from the tool type and the turning angle, and when executing the T code 22, refer to the table to select the offset number AT. You can Although the above embodiment has been described with respect to the case of being applied to a turning center, the method of the present invention can be applied to NC cutting machines with a tool turning shaft in general.

[0021]

According to the offset correction method of the present invention, the offset amount of the cutting edge position associated with the change of the turning angle of the tool is calculated in advance, and even for the same tool, a predetermined storage area is stored for each turning angle. Since it is stored, it is not necessary to calculate the offset amount during machining, the waiting time of the machine for the calculation is eliminated, and the cycle time is shortened.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an NC device of an NC cutting machine to which an offset correction method according to an embodiment of the present invention is applied.

FIG. 2 is a perspective view of a turning center that is the same cutting machine.

FIG. 3 is a flow chart showing an offset correction method in the embodiment.

FIG. 4 is a flowchart showing a conventional offset correction method.

[Explanation of symbols]

1 ... Spindle, 4 ... Milling head, 5 ... Tool changer, 1
4 ... NC device, 15 ... Machining program, 17 ... Offset calculation means, 18 ... Reference angle offset storage means, 20 ...
Each turning angle offset storage means, 22 ... T code, B ... axis

Claims (1)

[Claims] 1. Before starting machining, an offset amount of a cutting edge position based on a turning angle of a tool turning axis is calculated based on an offset amount set value of a reference angle, and a predetermined storage area is set for each turning angle of each tool. And a step of correcting the tool position by reading the corresponding offset amount in the storage area at the time of executing the tool command code at the time of machining.