JP2003251545A - Cutting tool life diagnosis system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the costs of cutting tools and maintain machining quality and solve such a peculiar problem as being liable to occur when the cutting tools are applied to a machining center etc. <P>SOLUTION: In a cutting tool life diagnosis system which are provided with a plurality of cutting tools 5 and a motor 8 for driving the cutting tools and is applied to a machining line comprising a machining center 20 or a plurality of machining centers 20 machining a workpiece 1 with cutting tools changed. The cutting tool life diagnosis system is also provided with a motor power consumption detection device 11 for measuring the effective electric power wave-form of the motor 8 and a control device 30, which determines the life of the cutting tools by memorizing the reference effective electric power wave- form of the motor 8 showing the life of each cutting tool 5 beforehand, transmitting a range switching command according to the changed cutting tool to the motor power consumption detection device 11 and comparing the effective electric power wave-form receiving from the motor power consumption detection device 11 and the reference electric power wave-form by recognizing their patterns recognition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade tool life diagnosis system for diagnosing the life of a tool for processing a work.

[0002]

2. Description of the Related Art Conventionally, as a cutting tool life diagnosing device, a vibrometer is connected to the driving shaft of the cutting tool, and when the vibration level during cutting exceeds the maximum value (judgment level) of the vibration level during normal cutting, A device that employs a vibration diagnosis method that determines that a chip has occurred is known.

[0003]

However, products such as sleeves for hydraulically controlled solenoid valves, which require high precision quality, are required to have sufficiently high cylindricity and surface roughness. In the method, there is a problem in that it is not possible to diagnose abnormalities due to the life of the cutting tool (abnormalities due to the life other than chipping) that occur below the determination level, and therefore it is not possible to detect cylindricity defects and surface roughness defects.

Therefore, in order to maintain the quality of processing, the timing of exchanging the cutting tool has been advanced, but this means that the cutting tool can be replaced before the normal service life of the cutting tool (the service life based on the total number of workpieces that can be processed by the cutting tool). Had to be replaced, leading to an increase in blade cost.

Therefore, the inventors of the present invention have made extensive studies as to measures for achieving both reduction of cutting tool cost and maintenance of machining quality, and as a result, the amount of electric power (effective amount of power) supplied to a motor for giving a driving force to the cutting tool and the cutting tool. Of the effective power waveform during the machining of the workpiece as the number of workpieces processed by the blade increases (usually, the blade deteriorates and the cylindricity and surface roughness decrease with this increase). The eccentricity and surface roughness caused by the unexpected end of tool life (cutting tool variation, abnormal workpiece setting, etc.) due to the unique change point of the active power waveform. It has been found that the quality abnormality of can be detected.

Prior to the present invention, the present inventors were able to accurately grasp the timing at which the cutting tool should be replaced based on the active power waveform of the motor based on the above knowledge, and the cutting cost of the cutting tool was reduced. An invention relating to a cutting tool life diagnosis device capable of achieving both maintenance of processing quality is provided. The invention that is the premise of the present invention will be described in detail in the first half of the "Embodiment of the Invention" described below. It was made for the purpose of solving. It should be noted that this peculiar problem will be described after the premise invention has been described in the following “Embodiment of the Invention”.

[0007]

According to a first aspect of the present invention, it is possible to accurately diagnose the service life of each cutting tool in a machining center, such as a machining center, which is used while exchanging a plurality of cutting tools or in a processing line including a plurality of processing centers. Becomes
The operator's labor for monitoring the life of a plurality of cutting tools can be reduced, and the work efficiency can be improved and erroneous work can be prevented. Further, since the motor power amount detection device measures the effective power waveform of the motor in the range according to the blade after replacement, it is possible to prevent the motor inrush power waveform from overranging, and the threshold value for pattern recognition can be set. It will be possible.

According to claim 2, after the motor is started,
Since pattern recognition is performed based on the active power waveform after the start of processing, various problems based on the motor inrush power waveform do not occur, and accurate life diagnosis is possible.

Further, according to the third aspect, since the warning that the blade has reached the end of its life is issued, it is possible to prevent a large number of defective products from being produced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the invention on which the present invention is based will be described with reference to the drawings.

FIG. 1 is a block diagram of a single-axis cutting tool diagnostic system to which a cutting tool life diagnosing device according to the premise invention is applied. This single-axis cutting tool diagnostic system uses a sleeve of a hydraulically controlled solenoid valve as a work and is incorporated in a finishing machine in a sleeve processing line as shown in FIG.

In FIG. 1, reference numeral 1 denotes a sleeve (workpiece) of a hydraulic control solenoid valve fixed to a jig 2. The hydraulic control solenoid valve, as shown in FIG.
The spool 4 is a valve that controls the hydraulic pressure by moving the spool 4 in the sleeve 1 in the axial direction depending on whether or not the coil 3 is energized.
The sleeve 1 has a cylindricity of, for example, 8 μm or less when manufactured,
A surface roughness of, for example, 2.4 μRz or less is required. Reference numeral 5 represents a cutting tool for cutting the work 1, for example, a diarea. The cutting tool 5 is attached to the tip of the main shaft 6,
The main shaft 6 is driven by a motor, for example, a three-phase induction motor 8 via a belt 7. The spindle 6 and the motor 8 are fixed on a slide 9 that can move forward and backward with respect to the work 1.

The cutting tool life diagnosing device 10 includes a motor power amount detecting device 11 for detecting the current and voltage of the motor 8 and measuring the active power waveform of the motor 8. The motor power amount detection device 11 measures the effective power waveform when the new blade 5 is attached to the spindle 6 and the work 1 is cut at the start of the life diagnosis of the blade 5. The measured active power waveform is treated as an initial waveform in the entire usage period (life period) of the cutting tool 5 by the pattern recognition type output monitoring apparatus 12, and the pattern recognition type output monitoring apparatus 12 uses the initial waveform as the initial waveform. The reference active power waveform indicating the life of 5 is set and stored. Here, as shown in FIG. 4, the initial waveform is represented by active power (%) that changes according to the cutting tool processing parts A to F of the sleeve 1. This active power has a one-to-one relationship with the cutting load, and has a large value when the cutting load is large and a small value when the cutting load is small. In addition, as shown as "feature 1" in FIG. 5, the reference active power waveform is similar to the active power waveform that shifts toward the increasing side as the blade wear (number of machining) increases, and the cylindricity and surface roughness are increased. Is deteriorated, as shown in "Characteristic 2", abnormalities in cylindricity and surface roughness can be detected by a specific change in the active power waveform, and when the cutting tool 5 is chipped. Paying attention to the point that the active power significantly decreases, an upper limit reference waveform obtained by multiplying the initial waveform by a predetermined number (for example, 1.4 times) on the increasing side and a predetermined multiple (for example, 0 .7 times) and a lower limit reference waveform.

The pattern recognition type output monitoring device 12 has an active power waveform actually measured by the motor power amount detecting device 11 and an upper limit reference waveform and a lower limit reference waveform during machining of each work 1 performed after setting the reference active power waveform. Is compared by pattern recognition, the life of the cutting tool 5 is determined, and when it is determined that the cutting tool 5 has reached the end of life, an alarm to that effect is given by a patrol light or the like.

7 to 9 exemplify a case where the pattern recognition type output monitoring device 12 determines that the cutting tool 5 has reached the end of its life. FIG. 7 shows a case where the cylindricity is poor. In the case of poor cylindricity, it can be seen from FIG. 7 that the waveform in the middle of the processing period has a portion exceeding the upper limit reference waveform. Figure 8
The case of poor surface roughness is shown. In the case of poor surface roughness, it can be seen from FIG. 8 that the waveform in the latter half of the processing period has a portion exceeding the upper limit reference waveform. FIG. 9 shows a case where the cutting tool 5 is defective due to chipping. In the case of chipping, it can be seen from FIG. 9 that the waveform greatly falls below the lower limit reference waveform during the processing period.

As explained above, the cutting tool life diagnosing device 10 according to the premise invention is a cutting tool life diagnosing device for diagnosing the life of the cutting tool 5 for processing the work 1 by obtaining the driving force from the motor 8, and depends on the cutting tool 5. A motor power amount detection device 11 for measuring the active power waveform of the motor 8 during work machining, and a motor active power waveform measured by the motor power amount detection device 11 during work machining by the new cutting tool 5 are taken in as initial waveforms, Based on the waveform, a reference active power waveform indicating the life of the cutting tool 5 is set, and after setting the reference active power waveform, the active power waveform measured by the motor power amount detection device 11 and the reference active power waveform are pattern-recognized. And the pattern recognition type output monitoring device 12 for determining the life of the cutting tool 5 by comparing the above. For this reason, according to the premise invention, in addition to chipping of the cutting tool 5, abnormalities in cylindricity and surface roughness due to deterioration of the cutting tool 5 can be detected, and the timing at which the cutting tool 5 should be replaced can be accurately grasped. It becomes possible to reduce the cost and maintain the processing quality at the same time.

Further, when the pattern recognition type output monitoring device 12 determines that the cutting tool 5 has reached the end of its life, an alarm is issued to that effect, so that appropriate processing such as machining stop and cutting tool replacement can be taken promptly. As a result, it becomes possible to promptly deal with the situation that leads to the production of a large number of defective products.

Next, there is a problem in applying the above-described premise invention to a machining center or the like, which is provided with a plurality of cutting tools 5 and one cutting tool driving motor 8 and is used for processing the work 1 while exchanging the cutting tools 5. explain.

In the above-described single-axis cutting tool diagnostic system, the main shaft 6 (motor 8) is constantly rotating after starting, so that FIG.
As shown in, it is easy to determine that the time when the active power exceeds a predetermined level in the active power waveform is the processing start time, and this time is accurately recognized as the trigger point for the cutting processing waveform (active power waveform) collection. be able to. However, in a machining center or the like, since a plurality of cutting tools 5 are used by being exchanged for one motor 8, the motor 8 repeats stop-operation-stop every time the cutting tools are replaced, and at the time of operation, As shown in FIG. 11, motor rush power (peak pulse) is generated. This motor inrush power waveform usually has a disturbance as shown in FIG. 12, and if a trigger point is set in the motor inrush power waveform,
There is a problem that the trigger point is deviated, and as a result, the cutting waveform is deviated, which makes it impossible to accurately determine the life. There is also a problem that the motor start-up waveform may be overranged as shown in FIG. 13, and it may not be possible to set the threshold for pattern recognition (reference active power waveform). Further, as shown in FIG. 14, there is a problem in that there is variation in the slope of the motor start-up waveform at the time of falling, and as a result, the cutting process waveform deviates and accurate life determination becomes impossible.

The present invention has been made for the purpose of solving the above-mentioned problems that occur when the premise invention is applied to a machining center or the like. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 15 shows the structure of a cutting tool life diagnosis system according to an embodiment, and shows a case where the cutting tool life diagnosis apparatus is applied to one machining center 20.

In FIG. 15, the machining center 20
Then, as described above, the plurality of cutting tools 5 and one cutting tool driving motor 8 are provided, and the cutting tool 5 is used by being replaced with the motor 8 (spindle 6).

The motor power amount detecting device 11 switches the range according to a range switching command from the waveform system 30 which will be described later according to the replaced blade, and measures the active power waveform of the motor 8.

The waveform system (control device) 30 is composed of a computer or the like, and for each blade 5 used in the machining center 20 in advance, an effective power waveform of the motor 8 when the workpiece 1 is machined using a new blade ( The reference active power waveform (upper limit reference waveform and lower limit reference waveform) set based on the initial waveform) is stored, and range switching information for each cutting tool 5 is stored. Here, the active power waveform (initial waveform) does not include the motor rush power as described above, and consists only of the processed waveform portion. That is, as shown in FIG. 16, the trigger point for waveform collection is set near the start of machining after motor startup. The trigger point setting method is that the active power value is taken in at a predetermined sampling cycle (for example, 2 ms) from the time of starting the motor, and the active power value taken in this sampling (if P
and the average value (assuming Po) of continuous n (for example, 10) active power values up to the previous time are compared,
After Pn <Po continues for a predetermined number of times, the point at which Pn> Po is switched is set as a trigger point. By setting the trigger points in this way, it is possible to obtain an active power waveform (initial waveform) that does not include the motor rush power and is composed of only the cutting waveform. In addition, the trigger point of the measured active power waveform which is compared with the reference active power waveform by pattern recognition at the time of life determination described later is also set in the same manner as above.

When the waveform system 30 receives the cutting tool information transmitted from the machining center 20, that is, the identification information of the replaced cutting tool 5 which is transmitted every time the cutting tool is replaced, the waveform power system 30 informs the motor power amount detecting device 11 of the same. The motor power amount detection device 1 is transmitted by transmitting the range switching information of the blade 5.
The range of 1 is set to be suitable for the cutting tool 5.

Further, when the waveform system 30 receives a machining start signal from the machining center 20 every time the cutting tool is replaced, the reference active power waveform of the cutting tool 5 is read out and measured from the motor power amount detecting device 11. The active power waveform and the reference active power waveform are compared by pattern recognition to determine the life of the cutting tool 5. The method of determining the life of the cutting tool 5 is the same as the method of determining the life of the pattern recognition type output monitoring device 12 in the above-described premise invention. As described above, this life judgment is performed only on the cutting waveform, excluding the motor inrush power waveform. Therefore, the above-mentioned problems based on the motor rush power waveform do not occur, and the life can be accurately determined.

When the waveform system 30 detects an abnormal waveform and determines that the cutting tool 5 has reached the end of its life, the waveform system 30 sends a facility stop signal to the machining center 20 to stop the machining center 20.

FIG. 17 shows the configuration of a cutting tool life diagnosis system according to another embodiment, in which a plurality of machining centers 2 are used.
The case where the tool life diagnosing device is applied to a machining line consisting of 0 is shown. In this case, the waveform system 30 performs the same processing as the processing with one machining center 20 described above between each machining center 20 and collectively manages the plurality of machining centers 20.

As described above, the cutting tool life diagnosis system according to the present embodiment is such that, in the machining center 20 or the like, a cutting center which is used while exchanging a plurality of cutting tools 5 or a processing line including a plurality of processing centers is used. Since it becomes possible to accurately diagnose the service life of the blades, it is possible to reduce the labor of the operator for monitoring the service lives of the plurality of cutting tools 5, improve work efficiency, and prevent erroneous work.

Further, since the motor power detection device 11 is configured to switch the range in accordance with the range switching command according to the replaced cutting tool 5 and measure the active power waveform of the motor 8, the motor inrush power waveform is Overrange does not occur, and it becomes possible to set a threshold for pattern recognition.

Further, since the waveform system 30 is configured to perform the pattern recognition based on the active power waveform after the motor is started and after the machining is started, the problem based on the motor inrush power waveform does not occur and the accurate life diagnosis is performed. Will be possible.

Further, when the waveform system 30 is configured to give an alarm to that effect when it is determined that the cutting tool has reached the end of its service life, it is effective in preventing the production of a large number of defective products.

[0033]

According to the tool life diagnosing system of the present invention, in addition to the effect of the premise invention, that is, the effect of ultimately reducing the cost of the tool and maintaining the processing quality can be achieved.
In machining centers, such as machining centers that are used while exchanging multiple cutting tools, or in a processing line consisting of multiple processing centers, the life of each cutting tool can be accurately diagnosed, and the labor required for the operator to monitor the life of multiple cutting tools. It is possible to reduce the work efficiency, improve work efficiency, and prevent erroneous work.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a single-axis cutting tool diagnostic system to which a cutting tool life diagnosing device according to an embodiment of the premise invention is applied.

FIG. 2 is a diagram showing a sleeve processing line to which a single-axis cutting tool diagnostic system is applied.

FIG. 3 is a configuration diagram of a hydraulic control solenoid valve in which a sleeve as a work is incorporated.

FIG. 4 is an explanatory diagram of an initial waveform.

FIG. 5 is an explanatory diagram of similar changes and specific changes of the active power waveform.

FIG. 6 is an explanatory diagram of a reference active power waveform.

FIG. 7 is an explanatory diagram of a determination example of defective cylindricity.

FIG. 8 is an explanatory diagram of an example of determination of surface roughness defect.

FIG. 9 is an explanatory diagram of an example of determining a defect due to chipping of a cutting tool.

FIG. 10 is an explanatory diagram of trigger points for waveform collection in the single-axis cutting tool diagnostic system.

FIG. 11 is an explanatory diagram of a motor rush power waveform generated when the premise invention is applied to a machining center or the like.

FIG. 12 is an explanatory diagram of a problem caused by a motor inrush power waveform.

FIG. 13 is an explanatory diagram of a problem caused by a motor inrush power waveform.

FIG. 14 is an explanatory diagram of a problem caused by a motor inrush power waveform.

FIG. 15 is a conceptual configuration diagram of a cutting tool life diagnosis system according to an embodiment of the present invention.

FIG. 16 is an explanatory diagram of trigger points for waveform acquisition.

FIG. 17 is a conceptual configuration diagram of a cutting tool life diagnosis system according to another embodiment.

[Explanation of symbols]

1 work 5 cutting tools 8 motor 10 Cutting tool life diagnosis device 11 Motor power detection device 12 Pattern recognition type output monitor 20 Machining Center (Processing Center) 30 Waveform system (control device)

Continued front page    (72) Inventor Koichi Kira             3-48 Takahata-cho, Nishinomiya-shi, Hyogo Kawatetsu Advan             Inside Tech Co., Ltd. F-term (reference) 2G024 AD10 BA12 CA19 DA06                 3C029 DD01 DD11

Claims (3)

[Claims] 1. A cutting tool life diagnosis system comprising a plurality of cutting tools and one cutting tool driving motor, which is applied to a processing center for processing a work while exchanging the cutting tools or a processing line comprising a plurality of processing centers. In accordance with the range switching command corresponding to the blade after replacement, the motor power amount detection device that measures the active power waveform of the motor and the reference active power waveform of the motor indicating the life of each blade are stored in advance, and the motor A range switching command corresponding to the blade after replacement is transmitted to the power detection device, and the effective power waveform received from the motor power detection device and the reference power waveform are compared by pattern recognition to determine the life of the blade. And a control device for operating the cutting tool life diagnosis system. 2. The cutting tool life diagnosis system according to claim 1, wherein the control device performs pattern recognition based on an active power waveform after the motor is started and after the machining is started. 3. The blade tool life diagnosis system according to claim 1, wherein the control device, when determining that the blade tool has reached the end of its life, gives an alarm to that effect.