JP5589460B2 - Tool holder mounting abnormality detection method and machine tool - Google Patents

Description

  The present invention relates to a tool holder mounting abnormality detection method and a machine tool.

  The machining center attaches a cutting tool for machining a workpiece to the tool holder, positions the conical tapered portion of the tool holder in the tapered hole at the tip of the spindle, and pulls the pull stud at the rear end of the tool holder with the force of the spring. Pull back and attach to the main shaft to clamp. Then, the workpiece is machined by rotationally driving the spindle on which the tool holder (tool) to which the cutting tool is attached is mounted. The machining center is a machine tool that can perform various processes while automatically exchanging multiple tools such as drills, taps, milling cutters, and boring tools. After that, engage the tool changer arm with the V groove of the flange part of the tool holder, pull out the tool holder from the main shaft, and then insert the tool holder with another cutting tool into the main shaft taper hole and clamp it in the same way Tool change is performed by the automatic tool changer (ATC).

  Machining centers often use cutting oil during machining, and cutting oil containing chips and dust adheres around the spindle. Or it adheres to the taper hole of the main shaft. If the tool holder is mounted and fixed on the spindle directly with the automatic tool changer using the tool changer arm, the taper between the spindle and the tool holder is clogged with chips and dust, and the center line of the tool holder is aligned with the center line of the spindle. Eccentricity or twisting may occur. When machining with such a tool with misalignment, the rotational runout (so-called tool runout) of the tool is large, so that, for example, in drilling, there is a problem that the hole diameter becomes large or is processed into an elliptical hole. . To solve these problems, measures are taken to detect machining abnormalities on the tool mounted on the spindle and stop the operation to prevent machining defects.

Japanese Patent Laid-Open No. 2002-200542 JP 2003-334742 A JP 9-29577 A

  As a method and apparatus for detecting an abnormal mounting of a tool mounted on a spindle of a machining center, the tool holder abnormal mounting apparatus described in Patent Documents 1 and 2 is well known, and these apparatuses are sold by measuring device manufacturers. . These anomaly detection methods are methods for checking the anomaly of the tool holder with the waveform of the tool holder, and have the advantage that the amount of shake can be detected and measured with extremely high accuracy (within approximately 10μ), but the price of the device is expensive. . Machine tool manufacturers purchase and use these devices, but depending on the workpiece, this high detection accuracy may not be required. It becomes expensive.

  Therefore, when the required detection accuracy is medium (approximately within 30 μm), the displacement detector as described in JP-A-9-29577 is attached to the outer peripheral surface of the rotating tool holder and the main shaft. A method is used in which the maximum and minimum values of the distance to the detection unit are measured, and the difference between them is used as the amount of deflection of the outer peripheral surface of the tool holder for determination, and a tool holder mounting abnormality is detected. As shown in FIG. 9, the detection unit 106 is attached to the end of the spindle 102 of the machining center 101, and the abnormality determination setting value registered in advance in the internal memory of the controller 105 of the displacement detector 104 and the detection unit 106 measure this method. This is known as a method of comparing the shake amount and determining whether the controller 105 is acceptable or not, and can be implemented at a lower cost than those described in Patent Documents 1 and 2 above.

  However, the controller 105 of the displacement detector 104 is installed inside the cover of the machining center 101 or in the control panel in order to facilitate wiring. The controller 105 has a display unit for displaying the measured value and a setting value input unit (such as an input key) 107 integrated with the controller 105. Therefore, there is a problem in maintenance and operability such as confirmation of the measured value and input of the set value. was there. When the controller 105 is installed on the operation panel side of the front surface of the machine, the wiring between the detection unit 106 and the controller 105 becomes long, which increases the possibility of malfunction due to disconnection in the movable unit and the influence of noise. Although it is possible to install a new display / setting device 110 via the I / O interface 109 of the CNC 108, the cost increases.

  In this method, the number of tools 103 that can detect an abnormality is limited to 16 or less. Increasing the number of detected tools can be handled by the option of the displacement detector 104, but increases the cost. In addition, this method requires the user to be familiar with the handling of the controller 105 in order to register the set value, and there is a problem that operators that can be operated are limited.

  An object of the present invention is to solve the above-described problems in the prior art, and to provide an inexpensive tool holder mounting abnormality detection method and machine tool that are excellent in maintainability and ease of operation.

In order to achieve the above object, the first problem solving means is to mount a tool having a cutting tool attached to a tool holder on a spindle, rotate the spindle to machine a workpiece, and automatically replace a plurality of tools. In a machine tool that performs predetermined processing in sequence, measures the displacement of the outer periphery of the rotating tool holder with a detector, and compares and determines with a set value for determination to detect an abnormality in mounting the tool holder, the control device includes a signal conversion device. A programmable logic controller equipped with an input / output communication device is built in, and the programmable logic controller is provided with an internal memory storing setting values and tool shake determination means, and the detector includes a detection unit and a control unit. The detection unit is attached to the outer peripheral surface of the tool holder at a predetermined interval to measure the shake, and the control unit can output an analog value of the measured value. The determination means outputs a shake measurement command to the detector via the input / output communication device, receives the measurement value as an analog voltage value in the signal conversion device, and receives the set value of the tool mounted on the spindle and the received value. The tool holder is detected by comparing and determining the measured value, and the setting value input / display means is registered in the memory of the control device. The setting screen is displayed on the display unit provided in the display, the setting value can be input on the setting screen, the input setting value is registered in the internal memory, and the setting value and the judgment result are displayed on the setting screen. gastric lines, in the internal memory, and stores the two settings of the reference values and tolerances, each tool No. A unique value is registered for each, a value obtained by adding a reference value and a tolerance is used as a determination value to be compared with the measurement value, and a reference value registration unit for registering the measurement value as a reference value in an internal memory is provided. The determination means can be activated by selecting only the tool holder mounting abnormality detection or the reference value registration means activation .
The operation of the first problem solving means is as follows. That is, by using an inexpensive displacement detector or signal conversion device, confirmation of measured values, input of set values, and the like can be performed outside the machine that is easy to operate. Moreover, since the input part of a detector is not used, anyone can input a set value easily.

The second problem-solving means is the above-mentioned first problem-solving means, wherein a start switch of the tool shake determination means is provided on the operation panel, and can be selectively activated depending on the length of the activation switch operation time. The registration completion of the tool is taught by blinking of the start switch, and it is possible to perform re-registration of the reference value of the tool when a tool holder mounting abnormality occurs and automatic registration of the reference value at the time of tool setup And The operation of the second problem solving means is that the measurement value can be confirmed, the setting value can be input or changed, etc. more efficiently on a dedicated setting screen, and they can be automatically performed.

  As described above, according to the tool holder mounting abnormality detection method of the present invention, it is possible to provide a tool holder mounting abnormality detection method that is excellent in maintainability and ease of operation and that is inexpensive. Further, according to the machine tool of the present invention, it is possible to provide a machine tool that is excellent in maintainability and ease of operation and that is inexpensive.

It is a block diagram which shows embodiment of this invention. It is a conceptual diagram of a setting value It is a flowchart of a tool shake determination means. It is a flowchart of a tool shake determination means. It is a figure which shows an example of the operation panel PB layout. It is a flowchart showing the procedure of the process at the time of tool mounting | wearing abnormality. It is an example of a setting screen. It is explanatory drawing of the treatment at the time of tool mounting | wearing abnormality. It is a block diagram which shows the conventional tool holder mounting | wearing abnormality detection method.

Hereinafter, a tool holder mounting abnormality detection method according to an embodiment of the present invention and a machine tool for performing the method will be described in detail with reference to the drawings.
First, the overall configuration of the apparatus according to the tool holder mounting abnormality detection method will be described with reference to FIG. The machine tool 1 of FIG. 1 mounts the tool T which attached the cutting tool 4 to the tool holder 3 to the main shaft 2, processes the workpiece by rotating the main shaft 2, and automatically replaces a plurality of tools T sequentially. It is a machining center that performs predetermined processing. The machining center 1 measures the deflection (hereinafter referred to as tool deflection) of the outer periphery of the rotating tool holder 3 with a displacement detector 5 and registers in advance as a measurement value of the tool deflection (hereinafter simply referred to as measurement value). The tool holder 3 has a function of comparing and determining a set value (hereinafter simply referred to as a set value) for determining the tool runout to detect an abnormal mounting of the tool holder 3 (hereinafter referred to as a tool mounting abnormality).

  The machining center 1 includes a CNC (control device) 7 in the control panel 6 and a CRT screen (display) 12 on the operation panel 11. An AD converter (signal conversion device) 9 is attached to the CNC 7. The CNC 7 incorporates a programmable logic controller (hereinafter referred to as PLC) 10. The PLC 10 is a sequence control device that executes a program such as a ladder, and includes an I / O interface (input / output communication device) 8. Then, it is located between the machining center 1 and the CNC 7 and controls input / output signals between the two via the I / O interface 8.

  The PLC 10 includes an internal memory 16 for storing the setting value 18 and a tool shake determination unit 17. The tool shake determination means 17 is a ladder program for realizing comparison / determination between the measured value and the set value. The tool runout determination means 17 is activated by an NC program or an M code command of an operator's MDI operation.

  As shown in FIG. 2, two set values 18 of a reference value (S-DATA1 to S-DATAn) and a tolerance (R-DATA1 to R-DATAn) are stored in the internal memory 16 of the PLC 10. . These set values 18 are respectively the tool No. A unique value is registered for each. As the reference value, a normal value of the shake accuracy of the tool T is registered. The normal value is the amount of deflection of the outer peripheral portion of the tool holder 3 when it is normally attached to the spindle 2. On the other hand, the upper limit value allowed for machining is registered as the tolerance, but is set to a smaller value in consideration of the deflection amount of the spindle 2 and the cutting tool 4. Ultimately, the dimensions of the workpiece after machining are measured and determined comprehensively. The set value 18 can be registered from the data screen for setting and displaying the data table of the PLC 10.

  A set value input / display means 14 is registered in the ROM (memory) 13 of the CNC 7. The set value 18 may be registered using the data screen of the PLC 10, but the set value input / display means 14 can improve the usability and maintenance at the time of registration. The set value input / display means 14 displays a dedicated setting screen shown in FIG. 7 on a CRT screen (display device) 12 provided on the operation panel 11 of the machining center 1 so that the set value can be input on the setting screen. To do. Then, the input set value is registered in the internal memory 16 of the PLC 10, and various data such as the set value 18 are displayed on the setting screen. In the present embodiment, the set value input / display unit 14 converts a custom macro (FANUC product name) into an execution format, registers it in the memory 13 and executes it (for example, macro executor: FANUC product). Name).

  The displacement detector 5 is an eddy current application sensor (for example, a high-speed, high-precision digital displacement sensor manufactured by Keyence), and a sensor head (detection unit) 19 and a controller 20 that digitally output an electrical signal corresponding to the displacement of the detected object. It consists of and. The sensor head 19 is attached to the end surface of the main shaft 2 of the machining center 1 with a predetermined distance from the outer peripheral surface of the tool holder 3. The sensor head 19 measures the upper limit value and the lower limit value (displacement) of the distance between the sensor head 19 and the rotating tool holder 3 attached to the main shaft 2 as “runout”, and digitally outputs the measured value to the controller 20. Specifically, the amplitude (peak-to-peak value) per cycle (one rotation) is the “runout” of the tool T (tool holder 3), which is a measured value.

  As shown in FIG. 9, the controller 20 of the displacement detector 5 includes a display unit, a set value input unit (such as an input key) and an internal memory. Also, as shown in FIG. 1, it has a data analog output function. Then, the controller 20 displays the measured value on the display unit and outputs it to the AD converter 9 as an analog voltage. The eddy current application sensor and the AD converter 9 are very inexpensive compared to the tool holder mounting abnormality device described in Patent Documents 1 and 2. In the present embodiment, there is no need to look at the display of the controller 20 or input a setting value for abnormality determination from the input unit as in the prior art, so there is no need to consider the visibility and operability of the controller 20. It can be installed in any place that does not hinder the operation of the machine, and the degree of freedom in design is high.

  Next, the tool shake determination means 17 will be described with reference to FIG. When the PLC 10 receives a command output from the CNC by an NC program or an operator's MDI operation, the PLC 10 activates the tool shake determination means 17 and measures the shake to the controller 20 of the displacement detector 5 via the I / O interface 8. A command is output (S101). Since the displacement detector 5 measures the deflection of the tool T mounted on the spindle 2 as described above and outputs the analog output, the analog voltage value is received via the AD converter 9 and used as a measured value (S102). In the next step, it is selected whether or not to register the measured value of the tool T as a set value in the internal memory 16 of the PLC 10 (S103). If non-registration is selected, the process proceeds to the step of comparing / determining the set value of the tool T and the measured value (S104).

  The comparison / determination method in S104 will be described in more detail with reference to FIG. A value obtained by adding the reference value and tolerance of the tool T stored in the internal memory 16 of the PLC 10 is compared with a measured value (S106), and a value obtained by subtracting the measured value from the value is used as a determination value. When it is positive, it is determined that the tool is normally attached (determination OK) (S107), and when negative, it is determined that the tool is abnormally attached (determination NG) (S108). Then, the determination result is displayed on the setting screen of the CRT screen 12 together with various data such as the setting value (reference value and tolerance) and the measured value by the setting value input / display means 14 as shown in FIG. As a result, the determination value is digitized as an actual allowable value, which is easy for the operator to understand and a history of determination results can be left.

  On the other hand, if registration is selected, the process proceeds to a step (S105) in which the measured value of the tool T mounted on the spindle 2 is registered in the internal memory 16 of the PLC 10 as a reference value. S105 is the reference value registration means 15. The reference value registration means 15 re-registers the reference value for registering the measured value of the tool whose shake determination result is NG as the new reference value of the tool in the internal memory 16, and automatically calculates the reference value at the time of tool setup. Registration is possible.

  The machining center 1 performs machining with the tool T mounted on the spindle 2 if no tool mounting abnormality is detected. On the other hand, if a tool mounting abnormality is detected, the CNC 7 outputs alarm information to stop the automatic operation of the machining center 1, displays the tool mounting abnormality on the setting screen, and notifies the operator of the occurrence of the tool mounting abnormality. The operator performs an operation when a tool mounting abnormality occurs, which will be described below, and cancels the tool mounting abnormality.

  The operation of the operator when the tool mounting abnormality occurs and the procedure of re-registration of the reference value by the tool shake determination means 17 will be described with reference to FIGS. FIG. 8 shows a tool installation program 28, a setting screen (FIG. 7), an operation panel PB layout (FIG. 5), an operation by the operator and a procedure for re-registering reference values (FIG. 6) when a tool attachment abnormality occurs. It is explanatory drawing of the whole treatment at the time of tool mounting | wearing abnormality which showed the relationship.

  The operator first selects the tool No. of the tool T on which the tool mounting abnormality has occurred, that is, the tool T mounted on the spindle 2. Is confirmed on the setting screen (abnormal state) shown in FIG. 7 (S1). Next, the operation mode 21 shown in FIG. 4 is switched from automatic to manual (S2), the abnormality reset PB22 is pressed (S3), and the abnormality is temporarily reset. Next, the tool no. Is selected by operating the digital switch 23 (S4). When the replacement tool extraction PB24 is pressed, a tool extraction program (not shown) is activated and the spindle 2 moves to a position where the tool T can be extracted from the spindle 2 (S5). The tool unclamp PB25 is pressed to release the clamp, the tool T is removed from the main shaft 2, the taper portion of the tool holder 3 and the vibration detected portion (in this embodiment, the flange portion of the tool holder 3) are cleaned, It is confirmed whether there is any abnormality such as a dent (S6). If there is no problem, the tool T is returned to the spindle 2, the tool clamp PB26 is pushed and clamped, and the replacement tool return PB27 is "slowly pressed" (S7).

  When the replacement tool return PB27 is pushed, the tool attachment program 28 shown in FIG. 8 is activated this time, the spindle 2 moves to a position where the rotation is not hindered (for example, the machine origin), the tool T rotates, and the tool described above The shake determination means 17 is activated (S8). If no tool mounting abnormality is detected by the tool shake determination means 17 because the tool holder 3 has been cleaned, the machining center 1 resumes processing. However, if a tool mounting abnormality is detected again, the operator will perform “retry” once again by cleaning and checking the tool to determine runout. However, if it is determined that the reference value needs to be reviewed, tool runout judgment The determination can also be made after “re-registering” the measurement value of the tool measured by the means 17 as a reference value.

  The tool attachment program 28 will be described. In the present embodiment, the tool shake determination means 17 is activated by an M code command in the program, for example, M40 and M41. In the M40 command, non-registration is selected in S103 of the shake determination unit 17, and the process proceeds to S104 to compare and determine the set value of the tool and the measured value. On the other hand, in the M41 command, registration is selected in S103 of the tool shake determination means 17, the process proceeds to S105, the reference value registration means 15 is activated, and the measurement value of the tool is registered in the internal memory 16 of the PLC 10 as a reference value. It has become. In the tool attachment program 28, M40 is instructed following the command of M41, and the M41 command is passed by “simply pressing” the exchange tool return PB27, and only M40 is instructed, and only the tool mounting abnormality is detected. In this embodiment, the time when the replacement tool return PB 27 is pressed is set to “short press” when less than 0.5 seconds and “long press” when 0.5 seconds or more are set.

  On the other hand, when the replacement tool return PB27 is "long pressed" (S11), the M41 command is not passed, the tool shake determination means 17 activates the reference value registration means 15, the reference value is re-registered, and the exchange tool is returned. The PB27 lamp blinks at high speed (S12) to notify that the re-registration of the reference value has been completed. In the procedure of the embodiment of FIG. 5, before re-registration, it is reconfirmed whether there is any abnormality such as dust adhesion, scratches or dents on the tool again (S9, S10).

  The tool attachment program 28 is used even when a tool attachment abnormality has not occurred. For example, the reference value can be automatically registered at the time of tool replacement using the tool attachment program 28. In this way, by registering the set value to be registered in the internal memory 16 of the PLC 10 separately into the reference value and the tolerance, the measurement value measured by the tool shake determination means 17 is re-registered as the reference value, It is possible to register automatically. It should be noted that a tool whose tolerance is not registered in advance cannot be registered by the reference value registering means 15, and a tool that does not require determination is not measured.

  Thus, since the tool holder mounting abnormality detection method and the machining center 1 described above use the inexpensive digital displacement detector 5 and AD converter 9, the price of the machining center 1 can be suppressed. Further, confirmation of measured values, input / change of set values, and the like can be performed on a dedicated setting screen displayed on the operation panel 11 of the machining center 1. This eliminates the need to look at the display of the controller 20 in the machine or on the rear side of the machine as in the past, or to input the setting value for abnormality determination from the input unit, and can be operated from the front of the machine. Will improve. Further, it is not necessary to consider the visibility and operability of the controller 20, and the controller 20 can be mounted at any place where there is no hindrance to the operation of the machine, and the degree of freedom in design is high. In addition, since it is not necessary to know the handling of the controller 20, anyone can easily input the set value, and the operators that can be operated are not limited.

Further, by registering the set value separately from the reference value and the tolerance, the reference value can be re-registered as an actual measurement value measured by the tool shake determination means 17 or can be automatically registered. Therefore, it is not necessary to measure the runout outside the machine, reattach it to the spindle 2, and input the measurement value by key, so that the operator's labor and tool setup time can be reduced. Further, by comparing the value obtained by adding the reference value and the tolerance with the measured value, the determination value is digitized as an actual allowable value, which is easy for the operator to understand, and a history of determination results can be retained.
As described above, according to the present embodiment, it is possible to provide a machining center equipped with a tool holder mounting abnormality detection method excellent in maintainability and ease of operation at a low price.

  The present invention is not limited to the above-described embodiment, and may be implemented by appropriately changing a part of the operation panel PB layout, the configuration of the setting screen, or the M code to be used without departing from the scope of the invention. can do.

1 Machining center (machine tool)
2 Spindle 3 Tool holder 4 Cutting tool 5 Displacement detector (detector)
7 CNC (control device)
8 I / O interface (input / output communication equipment)
9 AD converter (signal conversion equipment)
10 PLC (Programmable Logic Controller)
11 Operation panel 12 CRT screen (display)
13 ROM (memory)
14 Set value input / display means 15 Reference value registration means 16 Internal memory 17 Tool shake determination means 18 Set value 19 Sensor head (detection unit)
20 Controller (control unit)
27 Replacement tool return PB
T tool

Claims (2)

A tool with a cutting tool attached to the tool holder is mounted on the spindle, the spindle is driven to rotate, the workpiece is machined, multiple tools are automatically exchanged, the prescribed machining is performed sequentially, and the outer circumference of the rotating tool holder is displaced In machine tools that measure tool holders and detect tool holder mounting abnormalities by comparing and determining with the set value for determination,
A signal conversion device is attached to the control device, and a programmable logic controller equipped with input / output communication devices is built in.
The programmable logic controller is equipped with an internal memory that stores the set value and a tool shake determination means.
The detector is composed of a detection unit and a control unit, and the detection unit is attached to the outer peripheral surface of the tool holder at a predetermined interval to measure shake, and the control unit can output an analog value of the measured value.
The tool shake determination means outputs a shake measurement command to the detector via the input / output communication device, receives the measurement value by the signal conversion device as an analog voltage value, and sets the setting value of the tool mounted on the spindle. While comparing and judging the received measurement value to detect tool holder mounting abnormalities,
Setting value input / display means is registered in the memory of the control device, and the setting value input / display means displays a setting screen on a display provided on the operation panel of the machine tool, and the setting value is displayed on the setting screen. and enabling input registers the input setting values in the internal memory, have rows displayed setting and the determination result on the setting screen,
Two set values, a reference value and a tolerance, are stored in the internal memory. A unique value is registered for each, a value obtained by adding a reference value and a tolerance is used as a determination value to be compared with the measurement value, and a reference value registration unit that registers the measurement value as a reference value in an internal memory is provided.
A machine tool characterized in that the tool shake determination means can be activated by selecting only tool holder mounting abnormality detection or reference value registration means activation . Provided with an activation switch of the tool shake determination means on the operation panel, enabling the selective activation according to the length of the activation switch operation time, and teaching the completion of reference value registration by blinking the activation switch,
The machine tool according to claim 1, wherein re-registration of the tool holder the reference value of the tool during mounting abnormality occurs and, that it is possible to perform an automatic registration of the reference value when the tool setup.

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