JPS63300809A - Detecting device for break of tool - Google Patents

Abstract

PURPOSE:To surely detect a break in a tool by providing a tool detection position data holding means, tool positioning means, break detecting optical sensor, error detection optical sensor and a decision means or the like deciding the break detection for whether it is error dection or not. CONSTITUTION:After the completion of drilling work, a point end position of a drill 2 is positioned to a detecting position S by a moving mechanism 3. Thereafter, projectors 21, 25 are turned on irradiating a beam of light by an NC control part 6. Here the beam of light from the projector 21, when the drill 2 generates no break further with its position accurate, reaches not a light receiver 22, while the beam of light from the projector 25 reaches a light receiver 26. In this way, a decision part 28 performs a decision feeding its result to the NC control part 6. And the drill is transferred again to the next drilling work. While the beam of light from both the projectors 21, 25 reaches the light receivers 22, 26 when the drill 2 is broken, but the drill 2, detecting its break, stops the next drilling work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a tool breakage detection device suitable for small diameter tools.

(Prior art) There are processing machines in which a tool such as a drill is attached to the shaft of a drive motor, and the machining operation is performed by the rotation of this motor.In such processing machines, processing is performed by detecting tool breakage. above is necessary. Therefore, there are the following methods for detecting tool breakage. In other words, methods for detecting breakage during machining include monitoring and detecting changes in the load current flowing through the drive motor to which the tool is attached;
There are methods using the E (acoustic mission) method, methods of detecting breakage by vibration, and methods of detecting breakage by contacting a touch sensor with the tool before and after the completion of machining.

However, although there are various methods as described above, it is difficult to apply them particularly to detecting breakage of a tool with a small diameter, for example, 5φ. In other words, with a small diameter tool, the load during machining is small, so even if you monitor the load current flowing to the drive motor, the load will be 1 due to breakage! The reality is that the flow value does not change rapidly and breakage cannot be detected. In addition, even if the AE method is used, it is possible to detect tools with a large diameter, but as the diameter becomes smaller, the detection reliability decreases.Furthermore, with the method of detecting vibration, there is almost no change in vibration due to breakage, so it is difficult to detect tools with a large diameter. It is inappropriate. On the other hand, detection using a touch sensor is unsuitable because contact with the tool may bend the tool or, depending on the nature of the contact, cause the tool to break.

(Problems to be Solved by the Invention) As described above, each method cannot reliably detect breakage and has low reliability.

Therefore, an object of the present invention is to provide a highly reliable tool breakage detection device that can reliably detect tool breakage.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides data holding means that holds detection position data corresponding to various tools for detecting tool breakage, and a tool that positions the tool according to the detection position data. positioning means;
A breakage detection optical sensor is placed so that a light beam passes through the tip position of the tool, which is positioned based on the detection position data. It receives the detection signals from the optical sensor for detection and the optical sensor for breakage detection to determine whether the tool is broken, and also receives the detection signal from the optical sensor for false detection to determine whether the detection of a broken tool is a false detection. This is a tool breakage detection device that attempts to achieve the above object by including a determination means for determining.

(Function) By providing such a means, the tool is positioned according to the detected position data, and in this state, the breakage detection sensor irradiates the tool with a light beam, and the erroneous detection optical sensor irradiates at least the tip of the tool with light. The beam is irradiated. In this manner, the determination means detects breakage based on whether or not the irradiated light beam is received, for example, and determines whether the breakage detection is an erroneous detection.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a tool breakage detection device. In the figure, reference numeral 1 denotes a drive motor, and a small-diameter tool such as a drill for preparing a tap hole, that is, a drill 2 is attached to the drive motor 1. Further, the drive motor 1 is provided in a moving mechanism 3, and is moved in the vertical direction and in the direction of the arrow (A) by the operation of the moving mechanism 3. On the other hand, a detected position data file 4 is formed, and this file 4 stores detected position data indicating the positions of various tools 2 at the broken position. In other words, since each type of tool 2 has a different length and diameter, the tool 2 is
Even if the tool 2 is lowered by the moving mechanism 3 while attached to the tool 2, the tip position (cutting edge) of the tool 2 will differ depending on the various tools 2. Therefore, detection position data corresponding to the distance by which the tool 2 is lowered by the moving mechanism 3 is stored for each type of tool 2.

By the way, this detected position data file 4 is connected to the NCw control section 5, and the detected position data is read by the NC control section 5 and sent to the driver section 7. It is designed to move in the vertical direction. The driver unit 7 has a function of rotationally driving not only the moving mechanism 3 but also the drive motor 1, and the NC control unit 6 has a function of controlling the machining work by issuing commands to the driver unit 7 according to the machining work program. are doing.

Now, 20 is an optical sensor for detecting breakage, and the light emitter 21
and a light receiver 22. In addition, the floodlight 21
The diameter of the light beam irradiated from is, for example, a small diameter of 11 or less. The arrangement positions of the light projector 21 and the light receiver 22 correspond to the position of the tip of the tool 2 where the light beam irradiated from the light projector 21 is lowered according to the detection position data, and the irradiation direction of the light beam is the axis of the tool 2. It is perpendicular to the direction. Note that the light projector 21 and the light receiver 22 are respectively arranged on a detection stand 23 in which a hole 23a is formed. Further, a false detection sensor 24 is arranged below the detection stand 23. This false detection sensor 24 is composed of a light emitter 25 and a light receiver 26, and the arrangement positions of the light emitter 25 and the light receiver 26 are
The irradiation direction of the light beam emitted from the projector 25 at a predetermined distance below the arrangement position of the light receiver 26 is perpendicular to the axial direction of the tool 2. These light receivers 22
The detection signals outputted from the light receiver 26 are sent to the determination section 28 through the sensor control unit 27, respectively.

The sensor control unit 27 has a function of receiving a detection start command from the NC11JtlJ section 6 and sending out a lighting signal to each of the light projectors 21.25 to turn on each of the light projectors 21.25. Further, the determining section 28 has a function of receiving a detection signal from the light receiver 22 and determining that there is no breakage if the detection signal is at the rLJ level, and that there is a breakage if the detection signal is at the rHJ level. Furthermore, upon receiving the detection signal from the light receiver 26, the determination unit 28 determines that if this signal is at the rHJ level, the breakage determination is valid, and if the signal is at the rLJ level, the breakage determination is invalid and an erroneous detection has been made. It has a function of sending an emergency stop signal to the NC control section 6. Note that the NC control unit 6 sends the breakage detection determination result Q to a tool management room or the like.

Next, the operation of the apparatus constructed as described above will be explained according to the breakage detection flowchart shown in FIG. After finishing the machining work on the workpiece (not shown), step e1
When a decision is made to perform breakage detection, the moving mechanism 3
The drive motor 1 is moved above the breakage detection optical sensor 2o and the false detection optical sensor 24 by a mechanism not shown. After this movement, in step e3, N01110
The unit 6 reads detected position data corresponding to the drill 2 attached to the drive motor 1 from the detected position data file 4. Then, the NC control section 6 sends a movement $11111 signal to the driver section 7 in accordance with the read detection position data. Thereby, the moving mechanism 3 lowers the position of the drive motor 1 and positions the tip of the drill 2 at the detection position IS. When this positioning is completed, the process moves to step 4, where the NC control unit 6 sends a detection start command to the sensor control unit 27, whereby each of the projectors 21, 25 lights up and emits a light beam.

Here, if the drill 2 does not break and the moving mechanism 3 accurately positions the tip of the drill 2 at the detection position S, then
The light beam irradiated from the light projector 21 is irradiated onto the tip of the drill 2 and does not reach the light receiver 22. Therefore, the receiver 2
2 outputs a detection signal of the rLJ level and sends it to the determination section 28 through the sensor control unit 27. On the other hand, the light beam irradiated from the floodlight 25 is transmitted to the drill 2.
is positioned at the detection position S, so it reaches the light receiver 26. Therefore, a detection signal of the rHJ level is sent from the light receiver 26 to the determination section 28 through the sensor control unit 27. Thus, the determination unit 28 receives each detection signal and performs determination in step e5. In other words,
Since the detection signal from the light receiver 22 is at the rLJ level, the determination unit 28 determines that there is no breakage in the drill 2, and since the detection signal from the light receiver 26 is at the rHJ level, the breakage determination result is valid. It is determined that Thus, the determination section 28 sends this determination result to the NC control section 6. Then, move on to the next processing operation again.

However, if the drill 2 is broken, even if the moving mechanism 3 accurately positions the drill 2 at the detection position IItS,
The light beam emitted from the light projector 21 reaches the light receiver 22 without being blocked by the tip of the drill 2. Therefore, light receiving B2
2 outputs an rHJ level detection signal and sends it to the determination section 28 through the sensor control unit 27. On the other hand, the light beam irradiated from the light projector 25 reaches the light receiver 26 as described above. Therefore, from the photoreceiver 26, rH
The J level detection signal is sent to the determination section 28.

Thus, the determination unit 28 determines that the drill 2 is broken because the detection signal from the light receiver 22 is at the rHJ level, and the detection signal from the light receiver 26 is at the rHJ level.
level, the breakage determination result is determined to be valid. Thus, the determination unit 28 moves from step e6 to step e8 and outputs the emergency stop control signal to NCIll.
Send to 10 copies 6. As a result, the next machining operation is stopped.

By the way, when the drill 2 is not broken, detection position data that does not correspond to the drill 2 is read out from the detection position data file 4, and the tip position of the drill 2 is detected on the detection stand 23.
When the position of the drill 2- is reached through the hole 23a,
The light beam emitted from the light projector 25 is blocked by the drill 2' and does not reach the V receiver 26. Therefore, the receiver 2
The detection signal from 6 is at the rLJ level, and the judgment is 81!2.
8, even if it is determined that there is a breakage or no breakage, an emergency stop is applied to the feed shaft at the moment the detection signal from the light receiver 26 reaches the rLJ level. In other words, a function is provided to prevent tool breakage (due to malfunction) during the tool sequence.

In this way, in the above embodiment, the tool 2 is positioned, the breakage detection sensor 20 irradiates a light beam, and the erroneous detection optical sensor 24 irradiates the tool tip side with a light beam. Since the structure is configured to determine breakage detection and false detection based on the presence or absence of light reception, even if the drill 2 has a small diameter, a breakage of about 111IIl from the tip of the drill can be reliably detected. The reliability of detection can be improved. In particular, with respect to the detection judgment results, if there is an input error in the detection position data, this can not only be detected, but also damage to the tool breakage detection device can be prevented. or,
By transmitting the determination result to the N CIII I111 section 6, the processing work can be carried out efficiently in conjunction with the processing work.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, the determination unit 28 may determine whether or not breakage occurs depending on the time between light reception by the light receiver 22.

In addition, as shown in FIG.
The emitter 3 is placed in a direction perpendicular to the arrangement direction of the and receiver 22.
0 and its light receiver 31 may be arranged, and by arranging it in this way, even if the drill is broken only on one side as shown in FIG. 4, it can be reliably detected. In addition, the fourth
Breakage detection may be performed by rotating the drill 2 and the breakage detection optical sensor 20 relative to the breakage state shown in the figure. In addition, as a light sensor for false detection, a floodlight 2 is used as shown in FIG.
1 and the light receiver 22, the light emitter 32 and its light receiver 3
3, it is possible to detect the case where the drill is not lowered sufficiently due to an input error in the detection position data. Furthermore, the arrangement examples shown in FIGS. 3 and 5 may be combined.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a highly reliable tool breakage detection device that can reliably detect tool breakage.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a tool breakage detection device according to the present invention, FIG. 2 is a breakage detection flowchart of the device, and FIGS. 3 to 5 are diagrams for explaining modified examples. . DESCRIPTION OF SYMBOLS 1... Drive motor, 2... Drill, 3... Movement mechanism, 4... Detection position data file, 6... NG control section, 7... Driver section, 20... Brokenness Detection optical sensor, 21... Emitter, 22... Light receiver, 24...
- Optical sensor for false detection, 25... Emitter, 26... Light receiver, 27... Sensor control unit, 28.
... Judgment department. Applicant's agent Patent attorney Takehiko Suzue Figure 2: 22-()-7--Moto21 White ~ 30 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] data holding means that holds detection position data corresponding to various tools for detecting tool breakage; positioning means that positions the tool according to the detection position data; and a tip position of the tool that is positioned based on the detection position data. a breakage detection optical sensor disposed to allow a light beam to pass through the breakage detection optical sensor; an erroneous detection optical sensor disposed at least on the tool tip side in the tool axis direction close to the breakage detection optical sensor; determining means for receiving a detection signal from the optical sensor for determining whether or not the tool is broken, and for receiving a detection signal from the erroneous detection optical sensor for determining whether the detection of breakage of the tool is an erroneous detection; A tool breakage detection device characterized by comprising: