JPH0655407A - Collision prevention device of machine tool - Google Patents

Abstract

PURPOSE:To prevent a machine tool from making collision and eliminate breakage of an expensive machine caused by misoperation, by updating a stored work shape according to the change of the work shape through cutting along with detecting interference of a work with a tool and its interference with a machine to detect interference. CONSTITUTION:A work shape is measured by means of a work shape measuring instrument 17. The measured work shape is stored in a work shape storage 18. Shapes of a tool and a machine are inputted by means of a tool and machine shape input unit 19 and at the same time the input shapes are stored by means of a tool and machine shape storage 20. An interference check unit 21 checks if the work shape interferes with tool and machine parts when the parts of the tool and the machine to check interference move according to moving command from an NC program. In the case when abnormality is checked, the machine is stopped and at the same time an alarm generator 23 is operated. Change of the work shape is reflected to the work shape storage 18 by means of a work shape update unit 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing collision of machine tools.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional machine tool.
A work 2 (object to be cut) is fixed on the table 1, and the work 2 is cut by a tool 3 attached to the tip of a ram 4 that extends from a saddle 5 that moves in the Y-axis direction and moves in the Z-direction. Further, the table 1 moves in the X axis direction. The movement of each axis is pre-programmed as an NC program, and is realized by driving each axis motor in accordance with the instruction. The numerical controller 6 (hereinafter abbreviated as NC) performs a series of control from the interpretation of the NC program to the driving of the motor.

The structure of a conventional NC is shown in FIG. The NC program describing the movement of the tool for performing the desired machining is stored in the NC program storage unit 7. The NC program interpreter 8 reads the NC program from the NC program memory 7 in units of one block (one movement unit, for example, one line segment), and outputs information regarding the movement amount and movement speed of the block to the movement command generator 9. To do. The movement command generator 9 decomposes the input information such as the movement amount and the movement speed into the movement amount and speed of each axis, and outputs the information to the pulse distributor 10.
The pulse distributor 10 outputs the movement amount of each axis within a unit time, that is, the speed command to each axis servo amplifier 11, 12, 13 based on the input movement amount and speed information of each axis. The servo amplifiers 11, 12, 13 for each axis are driven by the motor 1 for each axis according to the speed command.
Drives 4, 15 and 16.

[0004]

As described above with reference to FIGS. 2 and 3, the NC machine tool cuts a work according to the NC program command, but has the following problems. . That is, when a wrong tool or a wrong work is attached due to a programming error in the NC program, an excessive cutting or a rapid feed causes a collision between the tool and the work. Further, with respect to a collision due to interference between each part of the machine other than the tool and the work (for example, interference between the ram tip and the work), there is currently no way of hitting, which may damage the expensive machine or the work.

An object of the present invention is to provide a device for preventing the above-mentioned collision of machine tools.

[0006]

Means for Solving the Problems The present invention, which achieves the above object, is a machine tool for driving a motor for each axis in response to a movement command from a numerical control device. And means for storing the shape of the machine part where the interference should be detected, means for detecting the interference between the work and the tool and the part of the machine where the interference should be detected based on the movement command from the numerical controller, by cutting It is characterized in that it has means for updating the stored work shape according to the change of the work shape.

[0007]

In a conventional numerically controlled machine tool, an alarm is generated or the machine is stopped when an abnormality occurs by obtaining a detection means for determining whether or not the work shape interferes with the tool and the machine part. Can be

[0008]

EXAMPLES Examples of the present invention will be described with reference to FIGS. 1 and 4 to 7. In FIG. 1, the same parts as those in FIG. 3 are designated by the same reference numerals. That is, in FIG.
Program memory 7, NC program interpreter 8, movement command generator 9, pulse distributor 10, each axis servo amplifier 1
1, 12, 13 and the respective axis motors 14, 15, 16 are shown in FIG.
Is the same as. In the present embodiment, a work shape measurement 17 for measuring the shape of the work prior to cutting is further provided. The workpiece shape measuring device 17 is, for example, a non-contact optical measuring device (measuring device using a triangulation method or a light cutting method).
Alternatively, or when the shape of the work is a simple shape such as a plate or a box, a contact type touch sensor is used.

FIG. 4 shows, as an example of the work shape measuring instrument 17, a measuring method by a light section method. That is, when the slit light generator 17a irradiates the workpiece 2 with slit light, when the workpiece 2 is irradiated with slit light, an optical image is obtained along the shape of the workpiece 2, and this is obtained by the CCD camera 17b. A light section image 17c corresponding to the shape of the work 2 can be obtained by imaging and monitoring.

The work shape memory 18 stores the measured shape of the work, and is usually realized by a magnetic memory device such as an IC memory or a disk.
By storing the Z coordinate for each 1 mm mesh of X and Y as shown in a simulated manner, the work shape is stored.

Further, the tool shape machine shape input device 19 can be realized by a keyboard, a floppy disk or the like, and can determine the coordinates of the machine interference check point and the shape of the tool as shown by the white circles in FIG. In other words, the tool length, tool diameter, and tool type are input.

The tool shape / machine shape memory 20 stores the data from the tool / shape / machine shape input device 19, and stores the shape of the tool used for cutting and the shape of the part configured to check the interference with the work. Remember.

The interference checker 21 is connected to the movement command generator 9, the work shape memory 18, and the tool shape machine shape memory 21 which are also shown in FIG. 3, and checks the tool and the interference according to the movement command of the NC program. It is checked whether or not the work shape stored in the work shape memory 18 interferes with the tool and the machine part when the part of the machine moves. In this case, when moving by cutting feed, since the cutting process is performed by the contact between the tool and the work, the interference between the tool and the work is not abnormal except when excessive cutting is generated.

An alarm generator 23 is connected to the interference checker 21, and the alarm generator 23 generates an alarm and stops the machine when an abnormality is detected by the interference checker 21. Also, the interference checker 2
1, a work shape updater 22 is connected to the work shape updater 22. The work shape updater 22 stores a change in the work shape due to cutting in the work shape memory 18 based on the result of the interference check between the tool and the work by the interference checker 21. This is reflected in the work shape.

The interference checker 21, the work shape updater 22, and the alarm generator 23 are realized as software operating on an electronic calculator (usually a microcomputer), and the details of this processing are shown in a flowchart in FIG. Show. That is, the interference checker 21 reads the movement command for one block (step A), determines whether or not the work interferes with the tool or the machine (step B), and if there is interference, determines whether cutting feed is in progress. Judgment (step C), an alarm is generated by the alarm generator 23 in the fast feed (step D), it is judged whether or not the workpiece and the machine interfere with each other in the cutting feed (step E), and an alarm is generated when they interfere. If the workpiece and the tool interfere with each other, it is judged whether or not the cutting is excessive (step G). If the cutting is excessive, the alarm generator 23 is driven (step H), and the excessive amount is generated. If not, the work shape updater 22 lowers the height of the part of the work shape data that interferes with the tool by the amount of interference (step I).

[0016]

As described above, according to the present invention, the shapes of the tool, the machine and the work are recognized prior to the cutting process,
Since collisions can be detected, expensive machines can be protected from damage due to erroneous operation.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of an example of a machine tool.

FIG. 3 is a block diagram of a conventional example.

FIG. 4 is an explanatory view of a light cutting method.

FIG. 5 is an explanatory diagram of a work shape storage method.

FIG. 6 is an explanatory diagram of a storage method of a tool shape and a machine shape.

FIG. 7 is a flowchart of collision detection.

[Explanation of symbols]

 17 Work Shape Measuring Device 18 Work Shape Memory 19 Tool Shape Mechanical Shape Input Device 20 Tool Shape Mechanical Shape Memory 21 Interference Check Device 22 Work Shape Updating Device 23 Alarm Generator

Claims (1)

[Claims] 1. A machine tool for driving a motor of each axis in response to a movement command from a numerical controller, means for measuring and storing a work shape, a shape of a tool and a shape of a part of a machine where interference should be detected are stored. Means, a means for detecting the interference between the work and the tool and the part of the machine where the interference should be detected based on the movement command from the numerical control device, and the stored work shape is updated with the change in the work shape due to cutting. A collision prevention device for a machine tool, comprising: