JPH11851A - Tool breakage detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the breakage of a tool in a short time by eliminating the transfer of a tool length to a numerical controller. SOLUTION: A tool breakage detecting device 12 mounted on and used for a machining center controlled by a numerical controller 6 has a communication line 26 connected to the numerical controller 6 for a machine tool, a tool length measuring means to measure the tool lengths L of a tool before and after mounted on the spindle of the machine tool and used for machining, a breakage judgement part 20 to compute a difference between the tool lengths before and after machining from the tool lengths measured by the tool length measuring means, before and after used for machining, and to output a breakage signal S4, if the difference between the tool lengths is equal to a preset value or more, and a communication control part 21 to output the breakage signal from the breakage judgement part 20 to the communication line 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool breakage detecting device capable of rapidly detecting a tool breakage without using a numerical control device of a machine tool such as a machining center.

[0002]

2. Description of the Related Art Conventionally, as a detector of this kind, a length measuring device for measuring a tool length is provided in an automatic tool changer outside a machining area, and an automatic tool changer is used by utilizing a tool change time. A tool to be used for the next machining with the tool attached to the exchange device (or the same for a tool that has been used. Hereinafter, only the case of determining the breakage of the tool used for the next machining will be described). Measures the tool length, transfers the measured value to the numerical controller of the machine tool, compares the measured value with the tool data stored in the tool data memory in the numerical controller, and compares the measured value with the tool in the numerical controller. If the tool length does not match the tool length stored in the data memory, it is determined that the tool has been cut.

Normally, the measurement itself by the length measuring device does not take much time, but the measured value measured by the length measuring device is transferred to the numerical control device, and the tool value of the corresponding tool in the tool data is further transferred. 10
You need more than a second.

[0004]

In this case, the machining performed by another tool in the machining area on the machine tool side is 1
In the case of processing that takes 0 seconds or more, there is no problem.
In the case of short machining that takes less than a second, the machine tool needs to replace the tool that has finished machining with the next tool that is currently measuring the tool length. It was in a standby state until a result was obtained, and unnecessary non-cutting time was generated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tool breakage detecting device capable of quickly detecting a tool breakage and preventing generation of useless non-cutting time as much as possible. It is assumed that.

[0006]

That is, according to the present invention, the invention of claim 1 is a tool breakage detecting device mounted and used on a machine tool (1) controlled by a numerical controller (6). In (12), the tool breakage detecting device is a communication line (26) connected to a numerical controller (6) of the machine tool.
And a tool length corresponding dimension (TL, TL) of the front and rear tools attached to the spindle (4) of the machine tool and used for machining.
Tool length measuring means (13, 15, 22, 25) for measuring TLM and TLMA, respectively, and from the tool length corresponding dimensions before and after used for machining measured by the tool length measuring means, before and after machining. A cut-off determining means (20) for calculating a difference between the tool lengths and outputting a cut-off signal (S4) when the difference between the tool lengths is equal to or more than a predetermined value, is provided. External communication means (21) for outputting a signal to the communication line is provided.

According to a second aspect of the present invention, the tool length measuring means has a sensor head (15) provided with detection light emitting devices (15a, 15b). ) Is reciprocally driven by a reciprocating drive device (13), and an emission light position for detecting a position of the emission light from a reference position when the detection light (15c) emitted from the detection light emission device is blocked. Providing detection means (16);
The detection light (1) detected by the emission light position detection means
The tool length measurement control unit (25) calculates the tool length corresponding dimension based on the position of the emitted light from the reference position when 5c) is blocked. Note that the numbers and the like in parentheses are for convenience showing the corresponding elements in the drawings, and therefore, this description is not limited to the description on the drawings. The same applies to the following “action” column.

[0008]

According to the above construction, the invention according to claim 1 of the present invention provides a tool length (T) before and after use of the tool (10).
L, TLM, and TLMA) to detect and determine a tool breakage. The invention of claim 2 acts so as to measure the tool length corresponding dimension of the tool in a non-contact manner.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a tool breakage detection device.
FIG. 2 is a perspective view showing an example of the machining center, and FIG. 3 is a view showing details of a sensor portion of the tool breakage detecting device.

As shown in FIG. 2, the machining center 1 has a body 2, and the outer periphery of the body 2 is covered with a cover 3. A processing area ARA covered with a cover 3 for processing a work is formed in front of the machine body 2 in the figure, and a table 5 for mounting a work (not shown) is provided in the processing area. Table 5
The main shaft 4 can be moved and driven in the horizontal directions indicated by arrows C and D by a driving device (not shown). It is provided so as to be movable in the directions B and the directions of the arrows E and F which are vertical directions.

A control box 3a having a built-in numerical controller 6 is provided behind the body 2 and an operation panel 6a constituting the numerical controller 6 is provided in the control box 3a. A tool magazine 7 containing a large number of tools is provided behind the machining area ARA, and a known automatic tool changer 9 for performing tool change between the tool magazine 7 and the spindle 4 is provided in front of the tool magazine 7. Is provided.

As shown in FIG. 1, the automatic tool changer 9 has a rod 9a, and an arm 9b is provided at the tip of the rod 9a. On both sides of the arm 9b, grippers 9c, 9c are provided so as to freely hold and release a tool 10 used in the machining center 1. On the side of arrow D of FIG. 1 between the tool magazine 7 and the arm 9b. A shifter 11 for exchanging tools is provided so as to be movable and movable in directions indicated by arrows E and F, that is, in a vertical direction.

At the upper part of FIG. 1 of the automatic tool changer 9, a tool breakage detecting device 12 is provided, and the tool breakage detecting device 12 has an air cylinder 13. As shown in FIG. 1, a rod 13a is attached to the air cylinder 13 by an arrow C,
The rod 13a is provided so as to be freely driven to protrude in the direction D.
A sensor head 15 is movably provided at a tip end of the sensor via a guide rail 14. As shown in FIG. 3, the sensor head 15 includes a light emitting unit 15 and a light receiving unit 15b, and the detection light 15c can be emitted from the light emitting unit 15 toward the light receiving unit 15b. FIG. 3 of the sensor head 15
A linear scale 16 is provided below along the directions of arrows C and D, and a reading head 16a of the linear scale 16 is fixed to the sensor head 15, as shown in FIG.

As shown in FIG. 1, the tool breakage detecting device 12 has a main control unit 17. The main control unit 17 has a cutout determination unit 20 and a communication control unit 21 via a bus line 19. , A sensor drive control unit 22, a tool length memory 23, and a tool length measurement control unit 25 are connected. The numerical control device 6 is connected to the communication control unit 21 via a communication line 26.

Since the machining center 1 has the above configuration, when machining is performed by the machining center 1, the tool magazine 7 is operated by a command from the numerical controller 6.
A predetermined tool 10 is taken out by a shifter 11 and supplied to a gripper 9c of an arm 9b of the automatic tool changer 9;
The automatic tool changer 9 supplied with the tool 10 supplies the tool 10 to the spindle 4 in the machining area ARA in such a manner that the tool 10 is replaced with the tool 10 mounted on the spindle 4 until then. The spindle 4 on which the new tool 10 has been replaced is immediately subjected to a predetermined processing by the tool 10 on a work (not shown) mounted on the table 5.

On the other hand, the arm 9b holding the tool 10 mounted on the main spindle by the one gripper 9c returns the tool 10 to the shifter 11, and the shifter 11 transfers the returned tool 10 to the tool magazine. 7 is returned to the predetermined pocket position. At this time, the tool 10 returned from the spindle
However, when the workpiece is cut during machining of the workpiece by the spindle 4,
If the processing is continued as it is, the defective workpiece processed by the cut tool is continuously processed, which is not only a large waste, but also there is a possibility that the tool in the cut state may be used in subsequent processing. Therefore, it is necessary to judge the cutting of the tool before returning it to the tool magazine 7, and if it has been cut, it is necessary to immediately issue an alarm and notify the operator.

The arm shown in FIG. 1 is a position where the shifter 11 takes out the tool 10 to be used for the next machining from the tool magazine 7 and transfers the tool 10 to the arm 9b of the automatic tool changer 9. When the tool 10 is positioned at the delivery standby position P1, the main controller 17 of the tool breakage detecting device 12 instructs the sensor drive controller 22 to measure the tool length of the tool 10 to be used next for processing. Command. The sensor drive control unit 22 receives this. The rod 13a of the air cylinder 13 is projected in the direction of arrow D. Then, the sensor head 15 provided at the tip of the rod 13a also moves on the guide rail 14 in the direction of arrow D toward the tool 10 positioned and held by the shifter 11 at the standby position P1.

When the sensor head 15 protrudes and moves in the direction of arrow D, the light emitting part 15a and the light receiving part 15b provided on the sensor head 15 are also held by the tool 10 held by the shifter 11.
The tool 10 moves in the direction of arrow D toward the tip 10a of the tool 10, and the tip 10a of the tool 10 crosses and blocks the detection light 15c emitted from the light emitting unit 15a toward the light receiving unit 15b during the movement. The shifter 11 is positioned at the standby position P1 so as to be aligned with the sensor head 15 in the directions indicated by arrows C and D.
5 is provided so as to be held in a form coinciding with the directions of the arrows C and D, which coincide with the directions of movement of the sensor 5, so that when the sensor head 15 moves in the direction of the arrow D, the detection light 15c accurately moves the tip 10a of the tool 10 Can be caught.

When the tip 10a of the tool 10 crosses the detection light 15c, the detection light 15c that has reached the light receiving portion 15b from the light emitting portion 15a is cut off by the tip 10a of the tool 10, and the output signal S1 of the light receiving portion 15b is output. Is the previous
The state changes from 1 to 0. When the output signal S1 changes to 0, the tool length measurement controller 25 outputs a cutting edge detection signal S2 to the sensor drive controller 22. Also, the tool length measurement controller 25. Is the measurement origin ZP of the detection light 15c emitted from the output of the reading head 16a of the linear scale 16 to the sensor head 15, ie, from the light emitting unit 15a to the light receiving unit 15b, when the detection light 15c is cut off by the tool 10. Is calculated as a dimension value TLM corresponding to the tool length TL before use of the tool 10 to be used in the future machining, and the tool length memory 23 is used.
Store in. The linear scale 16 includes the sensor head 1
The reading head 16a reads the scale 16b provided in the directions of the arrows C and D parallel to the moving direction of No. 5, and the value is constantly integrated by a counter (not shown). Therefore, when the detection light 15c is blocked by the tool 10, the sensor head 15, that is, the light emitting unit 15a to the light receiving unit 15b
The position of the detection light 15c emitted to the reference position with respect to the measurement origin ZP (that is, the protrusion amount L1 of the sensor head 15 in the direction of arrow D) is determined based on the integrated value output by the counter. The calculation can be easily performed by the control unit 25. In addition, the air cylinder 13 is a sensor head 1
After the detection of the tool 20 by 5, the length-measurable stroke is full, so that the tool is driven to protrude to the leftmost position in FIG. 3 and then continuously driven to return to the origin ZP.

When the shifter 11 positions the tool 10 at the standby position P1, the distance TX between the reference position SP of the tool 11 and the measurement origin ZP of the tool breakage detector 12 is always constant. The tip 10a of 10 is the detection light 15c
The projection amount L1 of the sensor head 15 (detection light 15c) based on the measurement origin ZP at the time of cutting off corresponds to the tool length TL of the tool 10 on a one-to-one basis. Accordingly, the tool length measurement control unit 25 calculates the amount of projection L1 in the direction of arrow D based on the measurement origin ZP of the sensor head 15 from the output of the reading head 16a of the linear scale 16, and calculates the value from this point onward. Tool length TL before use of tool 10 used in machining
There is no problem even if the dimension value TLM corresponding to the above is used.
The actual tool length TL may be calculated by subtracting the protrusion amount L1 from the distance TX, and the value may be stored in the tool length memory 23.

In this way, the dimension value TLM of the tool 10 to be used for machining, which is positioned at the standby position P1 before machining, is stored in the tool length memory 23. When the measurement of the tool length of the tool 10 is completed, the machining is completed. Machining by the tool 10M mounted on the spindle 4 in the area ARA is completed,
If a tool change is required, the automatic tool changer 9
Is driven by a command from the numerical control device 6, is held by the shifter 11, and the used tool 10M mounted on the spindle 4 is exchanged with the tool 10 whose tool length measurement is completed, and the tool length measurement is completed. The spindle 4 to which the tool 10 is attached immediately starts a predetermined machining. The used tool 10M is returned to the tool magazine 7 by the shifter 11, and the shifter 11 further takes out the tool 10N to be used for machining from the tool magazine 7 and positions it at the standby position P1. Wait for machining to end and start tool change. At this time, the tool breakage detection device 12 measures and calculates a dimension value TLM corresponding to the tool length TL for the extracted tool 10N at the standby position P1 in the same procedure as described above,
It is stored in the tool length memory 23.

When the machining using the tool 10 by the spindle 4 of the machining center 1 is completed, the used tool 10 and the tool 10N to be used next are exchanged by the automatic tool exchanging device 9 to continue the machining. However, for the tool 10 returned to the shifter 11 by the automatic tool changer 9, a cut-off detection operation is performed by the tool cut-off detector 12 before returning the tool 10 to the tool magazine 7.

To do this, the shifter 11 sets the standby position P1.
In a state where the tool 10 is positioned, the air cylinder 13 is driven to move the sensor head 15 in the direction of arrow D in FIG. 3 in the same manner as before machining, and the dimension corresponding to the tool length TL of the tool 10 after machining is used. Value TLMA to tool length measurement control unit 2
5, and outputs the dimension value TLMA to the cut-off determining section 20. When the dimension value TLMA of the tool 10 after machining is input, the cut-off determining unit 20 reads from the tool length memory 23 the dimension value corresponding to the tool length TL measured and calculated before machining of the tool 10. Read the TLM,
The change of the dimension value corresponding to the tool length before and after machining is calculated. That is, an operation of | TLMA-TLM | is performed, and when the result is, for example, 1 mm or less, the tool 1
0 determines that no tool cutting has occurred during machining by the spindle 4, and sends a non-cutting signal S3 to the numerical controller 6 via the communication control unit 21. The numerical controller 6 receives this and drives the shifter 11 to return the tool 10 to the tool magazine 7, and the tool to be used next to the tool 10N currently mounted on the spindle 4 from the tool magazine 7 and used for machining. 10
N2 is taken out, positioned at the standby position P1, and similarly, the tool breakage detecting device 12 measures and calculates a dimension value TLM corresponding to the tool length TL before machining, and stores it in the tool length memory 23.

As a result of the calculation of | TLMA-TLM |, if the change in the dimensional value corresponding to the tool length before and after the use of the machining exceeds, for example, 1 mm, the tool 10 is not being machined by the spindle 4. Is determined to have caused a tool cut, and a cut signal S4 is transmitted to the numerical controller 6 through the communication line 26 via the communication control unit 21. Immediately upon receipt of this, the numerical controller 6 interrupts the machining of the workpiece by the machining center 1 to stop machining of the defective workpiece that has been machined by the cut-off tool, and operates the display provided on the operation panel 6a. Notify the operator of the tool breakage via

It should be noted that the determination of the tool breakage is all performed in the tool breakage detection device 12, and only the determination result is output to the numerical control device 9 which directly controls the machining center 1. The side does not need any calculation for the determination of the tool breakage, and the operation for detecting the breakage of the tool 10 is performed at high speed.

Further, in the above-described embodiment, the case has been described in which the tool breakage detecting device 12 performs a cut-off determination for all the tools 10 mounted on the spindle 4 and used for machining. Since it is not necessary to perform the cut-off determination by 12 for all tools used for machining, a predetermined cut-off determination execution command is instructed by a M code or the like in a machining program for a tool for performing a cut-off determination. It is also possible to perform the cutting loss determination selectively for a tool used for machining.

[0027]

As described above, according to the present invention,
In a tool breakage detecting device 12 mounted and used on a machine tool such as the machining center 1 controlled by the numerical control device 6, the tool breakage detecting device is a communication line connected to the numerical control device 6 of the machine tool. A tool length measurement control unit for measuring a tool length corresponding dimension such as a tool length TL or a dimension value TLM or TLMA of a tool before and after being attached to the spindle 4 of the machine tool and used for machining; 25, a sensor drive control unit 22, a sensor head 15, a tool length measuring means such as the air cylinder 13, etc., and a tool length corresponding dimension before and after used for machining measured by the tool length measuring means, before and after machining. A tool length difference is calculated, and when the tool length difference is greater than or equal to a predetermined value, a tool loss determining unit such as a tool loss determining unit 20 that outputs a tool loss signal S4 is provided. External communication means such as a communication control unit 21 for outputting a cut-off signal to the communication line, the tool cut-off is detected and determined only by comparing the tool length corresponding dimensions before and after use of the tool. Therefore, when detecting and determining the cutting of the tool, the tool length corresponding dimensions and the like are transferred to the numerical control device 6 via the communication line, and compared with the tool data in the tool file of the numerical control device 6. Eliminate the need for time-consuming processes,
The tool breakage can be detected and determined in a short time, and the non-cutting time due to useless waiting for the determination on the machine tool side is prevented from occurring. As a result of the applicant's experiment,
Numerical control unit 6 for detecting and determining tool breakage
In the case where the tool length corresponding dimension is transferred via the communication line and compared with the tool data in the tool file in the numerical control device 6, it took 10 seconds or more until the determination result was obtained. In the case of the cutout detection device, the time was greatly reduced to less than 2 seconds.

The tool length measuring means has a sensor head 15 provided with a detection light emitting device including a light emitting portion 15a and a light receiving portion 15b, and the sensor head 15 is reciprocally driven by a reciprocating drive device such as an air cylinder 13. An emission light position detecting means such as a linear scale 16 for detecting a position of the emission light from a reference position when the detection light 15c emitted from the detection light emission device is cut off; The tool length measurement control unit 25 that calculates the tool length corresponding dimension based on the position of the emitted light from the reference position when the detection light 15c detected by the position detection means is cut off. Long dimension can be measured without contact, and measurement can be performed efficiently in a short time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a tool breakage detection device.

FIG. 2 is a perspective view showing an example of a machining center.

FIG. 3 is a diagram showing details of a sensor portion of the tool breakage detecting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Machine tool (machining center) 4 ... Spindle 6 ... Numerical control device 12 ... Tool breakage detection device 13 ... Tool length measuring means, reciprocating drive means (air cylinder) 15 ... Tool length measuring means (sensor) Head) 15a Detecting light emitting means (light emitting unit) 15b Detecting light emitting means (light receiving unit) 15c Detecting light 16 Detecting light position detecting means (linear scale) 20 Cutout determining means (Off) Loss determination unit) 21 External communication means (communication control unit) 22 Tool length measurement means (sensor drive control unit) 25 Tool length measurement means (tool length measurement control unit) 26 Communication line S4 Cut-off signal TL: Dimension corresponding to tool length (tool length) TLM, TLMA: Dimension corresponding to tool length (dimension value)

Claims (2)

[Claims] 1. A tool breakage detecting device mounted and used on a machine tool controlled by a numerical control device, wherein the tool breakage detecting device has a communication line connected to the numerical control device of the machine tool. Tool length measuring means for measuring a tool length corresponding dimension of a tool attached to the main spindle of the machine tool before and after being used for machining, and used for machining measured by the tool length measuring means. And calculating a difference between the tool lengths before and after machining from the tool length corresponding dimensions before and after the machining, and outputting a cutout signal when the difference between the tool lengths is equal to or greater than a predetermined value. A tool cut detection device comprising external communication means for outputting a cut signal output from the means to the communication line. 2. The tool length measuring means has a sensor head provided with a detection light emitting device, the sensor head is reciprocally driven by a reciprocating drive device, and the detection light emitted from the detection light emitting device is provided. An emission light position detection means for detecting a position of the emission light from a reference position when the emission light is blocked, and a reference for the emission light when the detection light detected by the emission light position detection means is blocked. The tool breakage detection device according to claim 1, further comprising a tool length measurement control unit that calculates the tool length corresponding dimension based on a position from a position.