JP3851419B2 - Tool chip defect inspection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a system for inspecting defects such as wear and chipping generated on a tool tip used by being mounted on a tool used in a machine tool, using a visual sensor.
[0002]
[Prior art]
For example, tool tips (hereinafter also referred to simply as “tips”) mounted on machine tools such as milling machines, lathes, or machining centers are worn or chipped beyond their allowable limits due to long-term use or processing of hard workpieces ( Hereinafter, defects such as “abrasion” or “chip-out”) occur. If the chip having such a deterioration is continuously used as it is, it naturally causes a processing defect.
[0003]
The simplest method for preventing machining defects due to chip defects is to periodically replace the chips based on the machining time, the number of times, and the like. However, it is not easy to accurately predict the occurrence point of wear or chipping that actually exceeds the tolerance from the processing time or the number of times. Therefore, if the replacement period is shortened, the probability that the occurrence of processing defects can be avoided increases, but the possibility of replacing a chip that does not have a defect increases. On the other hand, if the replacement cycle is lengthened, the probability that processing defects will occur increases.
[0004]
Therefore, it has been proposed to inspect whether or not the chip actually has a defect by using a contact type inspection device. However, the contact type inspection device is expensive and takes time to inspect because the contact type inspection device is expensive. There is a problem that it takes. There is also a method of detecting chip defects by taking advantage of the fact that abnormalities are likely to appear in the torque of machine tool shafts when chipping occurs, but the relationship between the magnitude of wear and chipping and torque abnormality is constant. Instead, it is difficult to detect defects with high reliability.
[0005]
[Problems to be solved by the invention]
  The basic object of the present invention is to quickly and surely detect the occurrence of defects such as wear and chipping exceeding the allowable limits of chips mounted on machine tools such as milling machines, lathes, and machining centers in a non-contact manner. Is to provide a chip defect inspection system that can solve the above-mentioned problems of the prior art.
[0006]
[Means for Solving the Problems]
  The tool tip defect inspection system of the present invention can detect defects caused by tool tip wear, chipping or both.Using the visual sensor means, the tool remains attached to the machine toolInspection using a visual sensorit canIt is what I did.
[0007]
  Therefore, in the present invention, a control device for controlling a machine tool is used.Mounted on the toolpluralTool tip at a predetermined inspection positionSequentiallyThe translation position and rotation position of the toolPositioningMeans to controlAnd with a visual sensor,Sensing is performed from a predetermined direction on the tool tip at the inspection position, and index data representing the size of the defect is obtained..
[0008]
In order to rationally select the inspection time, a usage integration time detecting means for detecting the usage usage time of the tool is provided, and the tool tip attached to the tool is determined in advance based on the output of the usage integration time detection means. The translation position and rotation position of the tool may be controlled so as to come to the inspection position.
[0009]
According to a typical aspect of the invention, the visual sensor means is photographed by analyzing the image acquired by the photographing by the camera means, and the camera means for photographing the tool tip at the inspection position from a predetermined direction. Means are provided for acquiring index data representing the size of the chipping of the tool tip.
[0010]
It is preferable that the index data indicating the size of the defect is compared with a predetermined criterion in the system to automatically determine the necessity of tool tip replacement. If a means for notifying a predetermined message when the determination result corresponds to the necessity of replacing the tool tip is further provided, the operator can be prompted to replace the tip.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Tool chip defect inspection system of the present inventionInIs, EngineeringA form in which a tool equipped with a tool tip is inspected while attached to a machine toolIs adopted. In addition,A form in which a tool is removed from a machine tool and a chip attached to the tool is inspectedAs a reference exampleExplanationKeep.
[0018]
    [Embodiment]
  FIG.According to the present inventionImplementationStateIt is the principal part block diagram which showed typically the whole structure of the system which concerns. The system includes a milling machine body FM, a milling machine control device FCL, and a visual sensor VS for inspecting chips. The milling machine control device FCL is a well-known device having a CNC as a main part, and is connected to the image processing device IP of the visual sensor VS via a communication interface.
[0019]
The CNC of the milling machine control device FCL includes a CPU, a memory, a work table, or an XYZ axis that controls the translation position of the tool, and a digital servo circuit that drives a spindle that rotates the tool. In the CNC memory, in addition to a program for controlling the entire system and a machining program, a timer register for storing an integrated value of the operating time of the tool is set.
The image processing device IP of the visual sensor VS is a well-known device having a CPU, a frame memory, a data memory, an image processing processor, a program memory, a communication interface, a general-purpose interface, etc., and is connected to the camera CM through the camera interface. The milling machine control device FCL is connected via a communication interface via a communication interface.
[0020]
In addition, the illumination device IL is connected via a general-purpose interface so that the missing portion can be shaded when the tool chip is photographed by the camera CM. The camera CM is installed at an appropriate position on the milling machine body FM. At the time of the tool tip inspection, the illumination device IL is turned on, and the camera CM takes a picture of the tool tip from a predetermined direction. The image processing device IP captures and analyzes the photographed image, creates index data representing the size of the defect, determines whether or not there is a need for chip replacement, and displays the result on the monitor MO with a predetermined message.
[0021]
As will be described later, these series of operations are executed by the CPU of the image processing apparatus IP controlling each unit according to an inspection program stored in advance in the program memory. The tool tip inspection may be performed as one of the periodic inspections. However, using the tool operation time integration function of the milling machine control device FCL, every time the operation time integration value after tool tip replacement reaches the reference value, the monitor MO An operator may be informed of the arrival of the time required for inspection by displaying a message requiring inspection above. In addition, when the inspection time is required, the inspection program may be automatically started after waiting for the machining stop so that the tool tip can be inspected without any command input from the operator.
[0022]
In FIG. 2, the installation mode of the camera CM is shown together with the outline of the milling machine body FM and the appearance of the console CS. The console CS shown in the lower left part of the figure accommodates the milling machine main body FM and the control device FCL, and also plays a role of preventing scattering of cutting waste, cutting oil, cooling water, or the like during processing. An opening / closing own door DR is provided in front of the console CS. By opening the opening / closing own door DR, an arbitrary portion of the milling machine body FM can be accessed. Therefore, the tip change when the tool tip is found to be missing is also performed by opening the opening / closing own door DR.
[0023]
Further, a control panel CTLP is provided in front of the console CS along with the opening / closing own door DR, and a milling machine control device FCL (not shown) is embedded behind the control panel CTLP. Although the illustration of the image processing device IP of the visual sensor VS is omitted, a design for accommodating in the console CS may be adopted.
[0024]
The milling machine main body FM housed in the console CS is a well-known machine as shown in the outline. The work table head WTH is provided on the side close to the door DR, and the spindle head on the side far from the door DR. SPH is provided. The work table head WTH is equipped with a work table WT, which is moved and positioned on the XY axes. The XY position of the work table WT is controlled according to the machining program by the CNC of the milling machine control device FCL.
[0025]
The spindle head SPH is equipped with a spindle unit SPU provided with a spindle (spindle) SP on which a tool (mill) 1 is mounted on a Z-axis drive mechanism, and is moved and positioned on the XY axes. Although the CNC of the milling machine control device FCL controls the XYZ position of the spindle unit SPU and the rotation speed of the spindle (spindle) SP according to the machining program at the time of machining, it is the same as the conventional one. The XYZ position (translation position) of the spindle unit SPU and the rotational position of the spindle (spindle) SP are positioned at the inspection position by the CNC.
[0026]
As shown in the enlarged view, the mill 1 is attached to the spindle SP that rotates around the Y axis with a plurality of tool tips 3 attached thereto using a chuck. As shown in the figure, the camera CM and the attached illumination device IL are installed at a position corresponding to the side of the operation area of the spindle unit SPU in a posture having a line of sight in the X-axis direction. The XYZ position (translation position) of the spindle unit SPU at the time of inspection is taught in advance to the milling machine control device FCL as a position suitable for photographing the chip mounting portion of the mill 1 by the camera CM under illumination of the illumination device IL.
[0027]
Further, the rotational position of the spindle SP at the time of inspection is set in advance to the milling machine control device FCL together with the above-mentioned translation position as a position where the chip 3 to be inspected is satisfactorily photographed by the camera CM (in this example, the sight line front position) Be taught. When a plurality (N) of tool tips 3 are sequentially inspected, there are a plurality (N) of rotational positions that allow each of the tool tips 3 to come to the front-of-sight position of the camera CM with respect to the rotational position of the spindle SP. Be taught. The distance between the camera CM and the inspection target tool tip 3 at the inspection position is preferably such that an image of the tool tip 3 (see FIG. 3 described later) fits in the visual field with some margin.
[0028]
FIG. 3 shows an image photographed by the camera CM for the chip 3 of the tool (mill) 1 positioned at one inspection position. When the chip 3 is viewed from the front, it has a substantially rectangular shape, and as the machining time accumulates, wear gradually progresses from one edge portion EG, and a recess A is formed. Wear may be chipped. The recess A thus formed is photographed as a relatively dark portion by the camera CM. If the direction of illumination by the illumination device IL is devised, the concave portion A can be emphasized as a clearer shadow portion and photographed.
[0029]
In this embodiment, the necessity of replacing the tool tip 3 is recognized as index data for recognizing the expansion of the recess A by the expansion L in the Y-axis direction and the expansion D in the Z-axis direction, and determining L and D as the necessity for replacement. adopt. As the determination logic, the allowable values L0 and D0 are set in advance in L and D, respectively, and the logic that determines that replacement is necessary if at least one of the detected L and D exceeds L0 or D0 is adopted. . Needless to say, the logic for determining the necessity of replacement can be variously modified. For example, L + D or L² + D² It is conceivable to provide a tolerance value for.
[0030]
Next, an overview of the inspection procedure and related processing executed using the above system configuration / function will be described with reference to the flowchart of FIG.
The CPU of the milling machine control device FCL, for example, checks the value of the machining time integration timer register set therein every time machining of one workpiece is completed, and determines whether or not the inspection time required has come (step U1). ). If the time required for inspection has not arrived, the chip inspection is unnecessary and the processing is terminated. If the time required for inspection has arrived, chip inspection is necessary, and the process proceeds to step U2 and subsequent steps.
[0031]
In step U2, the CPU of the milling machine control device FCL moves the XYZ axes by the CNC and positions the spindle unit SPU with respect to the XYZ position (translation position). Further, in step U3, the spindle SP is rotated to position the rotation position of the spindle SP at the i-th inspection position. i is an index corresponding to the chip number. Here, it is assumed that a total of n chips are attached to the tool (mill) 1.
[0032]
When positioning for the inspection for the i-th chip is completed, an inspection command is transmitted to the image processing apparatus IP (step U4). The CPU of the image processing apparatus IP that has received the inspection command turns on the illumination device IL in step U5 (if it has already been turned on, the lighting can be maintained). Next, a shooting command is sent to the camera CM, the i-th chip image (see FIG. 3) is taken into the frame memory of the image processing device IP (step U6), an image analysis program is started to perform image analysis by the image processor, and i Index data Di and Li representing the size of the defect for the second chip are obtained and stored (step U7).
[0033]
Subsequently, the presence / absence of an uninspected chip is checked based on the magnitude relationship between the value of the index i and a preset total number n (step U8). If there is an uninspected chip, the index i is incremented by 1 (step U9), the process returns to step U3, and the rotational position of the spindle SP is positioned at the inspection position of the next chip. Thereafter, steps U4 to U9 are repeated until there is no uninspected chip.
[0034]
If there are no uninspected chips, the process proceeds from step U8 to step U10, and the stored index data D1 to Dn and L1 to Ln are related to the preset allowable value D0 of the index D and the allowable value L0 of the index L. Check. If Di is less than or equal to D0 (or less) and Li is less than or equal to L0 (or less) for all chips, it is determined that no replacement is necessary, and a notification means on the monitor MO screen or voice is provided. A message that does not require replacement is output (step U11), and the process is terminated.
[0035]
In other cases, that is, if Di is less than or equal to D0 (or less) or Li is less than or equal to L0 (or less) for any of the chips, it is determined that no replacement is necessary, and a notification means on the monitor MO screen or audio is provided. At the same time, a message notifying the necessity of replacement and the number of the chip to be replaced is output (step U12), and the process is terminated.
[0036]
    [Reference example]
  Next, refer to FIG.Reference exampleWill be described. FIG.Reference exampleIt is the principal part block diagram which showed typically the whole structure of the system which concerns on. The system is supplied with milling machines # 1 to # 3, robots # 1 to # 3, travel axis RL of robot # 1, hand exchange mechanism with replacement hands for robot # 1, and unmachined workpieces Unprocessed workpiece supply section WS1, processed workpiece storage section WS2 in which processed workpieces are stored, chip replacement rack CH in which replacement chips for milling machines # 1 to # 3 are prepared, for inspection and replacement of chips A chip inspection / exchange work table TB and a visual sensor VS for inspecting chips are included.
[0037]
[1] Outline of the system main part
(1) Milling machines # 1 to # 3; As is well known, a milling machine rotates a tool called a mill equipped with a machining tip (hereinafter simply referred to as “chip”) to cut a metal workpiece. On the machine tool, several units (here, three units) are arranged along the traveling axis RL of the robot # 1 (FIG. 5).
[0038]
FIG. 6 is an enlarged view of the appearance of a worn tip together with the appearance of a mill used in each milling machine. As shown in the figure, the mill indicated as a whole by reference numeral 1 has a tapered portion 1a and a head 1b. The mill 1 is attached to the milling machine by attaching the tapered portion 1a to a spindle (not shown) on the milling machine body side. The mounting posture of the mill 1 is precisely regulated by a keyway provided in a pair on the tapered portion 1a and the spindle.
[0039]
The head 1b has a gear-like shape, and a chip 3 is mounted on one corner of a plurality (eight in this example) of the convex portions 2 using fixing bolts 4. As shown in the enlarged view, the tip 3 has a flank face 6 and a rake face 7, and the rake face 7 is provided with a bolt hole 5 through which the fixing bolt 4 is passed. The unused chip 3 has a shape such as a rectangular parallelepiped shape or a triangular prism shape, but the wear part 8 is generated as the use is repeated.
[0040]
As shown in the figure, the wear portion 8 is formed so as to scoop out a portion along the intersection line 9 between the flank 6 and the rake face 7 from the front end side of the head 2. At this time, the width to be removed has a property that the flank face 6 is wider than the rake face 7 (d> d ′). Moreover, depending on the case, a part of wear part 8 may be crushed and the drop-off part 8a may arise.
[0041]
Each milling machine # 1 to # 3 is connected to a milling machine control device (see FIG. 50, FCL # 1 to FCL # 3 described later). The milling machine control device is a well-known device, and has a function of rotating the spindle shaft at a predetermined rotational speed, a function of positioning the spindle shaft, a function of integrating usage time for each tool, etc. according to an operation program. Therefore, a signal notifying the arrival of the tool inspection time can be output to the system at a predetermined cycle. Further, when the rotation of the spindle is stopped for the chip inspection according to the signal, the operation program can instruct the head 1a to face a predetermined direction.
[0042]
(2) Robot # 1; normally, the milling machines # 1 to # 3, the unmachined workpiece supply unit WS1, and the machined workpiece storage unit WS2 are accessed using the travel axis RL, and the milling machines # 1 to # 3. Load / unload workpieces. When the tip inspection time arrives in any of the milling machines # 1 to # 3, the hand replacement mechanism H is accessed to replace the hand with one for gripping the mill, and the mill 1 is removed from the spindle of the milling machine # 1. Remove and transfer to the chip inspection work table TB and fix. When resuming the loading / unloading of the workpiece, the hand replacement mechanism H is accessed again to return the hand to the workpiece gripping mechanism.
[0043]
FIG. 7 is a schematic diagram illustrating a state in which the mill 1 is fixed to the jig JG on the chip inspection work table TB. As shown in the figure, the robot # 1 travels on the travel axis RL, approaches the chip inspection work table TB, and attaches the jig JG to the taper portion 1a of the mill 1 gripped by the hand HD for gripping the mill. Fit into the hole HL. In order to fix the mill 1 in a predetermined posture, a keyway similar to that provided in the spindle is provided in the mounting hole HL. The jig JG has a function of opening and closing the chuck.
[0044]
(3) Robot # 2 and Robot # 3; Robot # 2 is a robot for performing chip cleaning and chip replacement on the mill 1 fixed to the jig JG on the chip inspection work table TB. On the other hand, the robot # 3 is a robot for projecting a structure light for performing chip inspection onto the chip. FIG. 8 is a schematic diagram for explaining the work status of the robots # 2 and # 3. As shown in the figure, an air gun AG and a small nutrunner NR are attached to the hand of the robot # 2.
[0045]
Prior to the chip inspection, the air gun AG blows out compressed air toward the chip 3 to clean the chip 3. The nut runner NR performs the tightening / loosening operation of the nut 4 for fixing the chip (see FIG. 6) when the chip 3 is replaced. The operations of the air gun AG and the nutrunner NR are controlled by a robot control device (see reference numeral RCL # 2 described later) that controls the robot # 2.
[0046]
On the other hand, the structure light unit SU is attached to the hand of the robot # 3. The structure light unit SU constitutes a light projecting / photographing unit of the visual sensor VS (see FIG. 5), and projects the structure light SL toward the chip 3 to be inspected through the structure light projecting window 11. The chip 3 on which the structure light SL is projected is photographed through the photographing window 21.
[0047]
FIG. 9 is a schematic view illustrating the (a) the structure of the main part of the structure light unit SU and (b) the structure light forming method. The structure light unit SU shown in FIG. 9A projects slit light as the structure light SL. The light projecting unit includes a laser oscillator 12, a cylindrical lens 13, a galvanometer 14 including a deflection mirror, and light projection. A window 11 is provided, and the photographing unit is provided with a CCD camera 20 and a photographing window 21. As shown in FIG. 9B, the laser beam emitted from the laser oscillator 12 is converted into slit light SL by the cylindrical lens 13. The slit light SL is deflected in a predetermined direction according to a command value instructing the light projecting direction by the galvanometer 14 capable of high speed driving, and is projected from the light projecting window 11. It is assumed that calibration of the slit light projector including the galvanometer 14 and the camera 20 has been completed.
[0048]
The operation of the robot # 3 and the operation of each part of the structure light unit SU (camera, laser oscillator, galvanometer, etc.) are controlled by a robot control device of a type incorporating an image processing device. FIG. 10 is a principal block diagram illustrating an outline of the configuration and the connection relationship with other elements.
[0049]
The robot control device RCL # 3 of the robot # 3 corresponds to the main control device of the entire system, and includes a central processing unit (hereinafter referred to as CPU) 51 as shown in FIG. The CPU 51 includes a ROM 52, a RAM 53, a nonvolatile memory 54, a teaching operation panel 55 having a liquid crystal display, a digital servo circuit 56 for controlling each axis of the robot, and an interface for a structure light unit. 61, an image processor 62, a monitor interface 63, a frame memory 64, a program memory 65, a data memory 66, and a communication interface 67 are connected via a bus 58.
The digital servo circuit 56 is connected to the mechanism unit of the robot # 3 via the servo amplifier 57 in order to control each axis of the robot # 3. The structure light unit SU 61 is connected to the structure light unit interface 61, and a monitor MO made of, for example, a CRT is connected to the monitor interface 63. In order to exchange commands and data related to a series of operations described later, external devices (such as robot control devices RCL # 1, RCL # 2, milling machine control devices FCL # 1 to FCL # 3) are connected to the communication interface 67. Communication interface equipped on each external device) is connected. The control devices RCL # 1, RCL # 2, and FCL # 1 to FCL # 3 are connected to each other via a communication interface provided in each.
[0050]
The ROM 52 stores various programs for the CPU 51 to control the robot # 3, the robot controller RCL # 3 itself, and control input / output to / from an external device. The RAM 53 is a memory used for temporary storage of data and calculation. The nonvolatile memory 54 stores operation program data that defines the operation of the robot 33 and the external device, related setting values, and the like.
[0051]
The structure light unit interface 61 is used to exchange commands for controlling each part of the structure light unit SU and to capture images taken by the camera 20 (see FIG. 9A). The captured image is temporarily stored in the frame memory 64 after being converted to gray scale. The image stored in the frame memory 64 can be displayed on the monitor MO.
[0052]
  The program memory 65 stores a program for performing image processing and analysis using the image processing processor 62, and the data memory 66 stores setting data related to image processing and analysis. BookReference exampleIn particular, the stored data includes program data defining processing for inspection of chip wear and chipping and associated setting data. The contents of the inspection process will be described later.
[0053]
Further, the configuration and functions of the main parts of the robot control devices RCL # 1 and RCL # 2 are similar to those of the robot control device RCL # 3 and are well known, so detailed description thereof will be omitted. However, the controlled object of the robot controller RCL # 1 includes the traveling axis RL, and the controlled object of the robot controller RCL # 2 includes the air gun AG and the nutrunner NR. Since the configurations and functions of the milling machine control devices FCL # 1 to FCL # 3 are also well known, detailed description thereof will be omitted.
Next, an outline of the work procedure executed using the above system configuration / function will be described in order in a bulleted form. The sequence described here is executed in accordance with a program taught to a control device related to operations included in the sequence. Except for the chip inspection operation described later, the processing for these operations is a well-known matter, and the details thereof are omitted.
[0054]
[2] Work procedure
(1) During normal work in which chip inspection is not performed, robot # 1 repeats loading of unprocessed workpieces and unloading of processed workpieces on each of milling machines # 1 to # 3 while repeatedly moving using travel axis RL. .
(2) The milling machines # 1 to # 3 that have received the work loading by the robot # 1 perform the cutting process according to the machining program taught by the associated milling machine control devices FCL # 1 to FCL # 3, and perform machining for each tool. Accumulate execution time.
[0055]
(3) Milling machine control devices FCL # 1 to FCL # 3 belonging to milling machines # 1 to # 3, which have been subjected to workpiece unloading by robot # 1 after machining of one workpiece, are integrated machining execution time values of tools. If a preset time limit has been exceeded, an inspection required signal is sent to the robot controller RCL # 1 of the robot # 1 and related data (such as the milling machine that sent the data and data that specifies the inspection tool required) Send with. Since the spindle with the mill attached stops at the taught rotational position, the attitude (orientation) of the mill at the time of stopping is constant every time.
[0056]
(4) The robot control apparatus RCL # 1 that has received this exchanges the hand of the robot # 1 with the hand HD for milling (see FIG. 7), and then moves it in front of the milling machine that performed the transmission.
[0057]
(5) The robot control apparatus RCL # 1 causes the hand HD of the robot # 1 to enter the milling machine and grasps the inspection mill 1 that is stopped. Since the posture (orientation) of the mill 1 at this time is constant, the mill 1 is held by the hand HD in a constant posture.
(6) The robot controller RCL # 1 sends a completion signal for the gripping operation of the mill 1 to the milling machine controller. Upon receiving this, the control device of the milling machine loosens the chuck of the spindle that fixes the mill 1 and releases the restraint of the mill 1.
[0058]
(7) The robot controller RCL # 1 removes the mill 1 from the milling machine and moves it to the robot # 1 in front of the chip inspection work table TB while holding the mill 1 (see FIG. 7).
(8) The robot controller RCL # 1 causes the robot # 1 to mount the mill 1 on the jig JG of the chip inspection work table TB, outputs a chuck close signal, and clamps the mill 1 to the jig JG.
[0059]
(9) The robot controller RCL # 1 moves the robot # 1 away from the chip inspection work table TB and sends a mill fixing completion signal to the robot controller RCL # 2. Then, the hand is again exchanged for the work, and the normal work loading operation for the milling machine not stopped for the mill inspection is returned.
[0060]
(10) The robot control device RCL # 2 that has received this uses the air gun AG to remove chips and the like adhering to the chip 3 mounted on the mill 1 while moving the robot # 2 around the mill 1. To remove (cleaning work).
[0061]
(11) When the cleaning operation is completed, the robot controller RCL # 2 moves the arm of the robot # 2 away from the mill 1 (to avoid interference with the robot # 3 during chip inspection), and sends a cleaning completion signal to the robot controller RCL #. Send to 3.
(12) The robot control device RCL # 3 that has received the inspection inspects all the chips 3 using a visual sensor. The chip inspection is performed in such a manner that the robot movement to the inspection positions for each chip inspection taught in advance (generally, the same number as the number of chips is taught) and the chip inspection by the visual sensor are repeated. The procedure and processing of individual chip inspection will be described in [3] below.
[0062]
(13) The robot controller RCL # 3 sends the inspection results for all the chips (data for specifying the mounting addresses on the mill of all exchangeable chips) to the robot controller RCL # 2.
(14) The robot controller RCL # 2 that has received the data specifies the tip replacement program taught in advance for the robot # 2 and the mounting address on the mill for the replacement tip if there is at least one replacement tip. The chip is replaced based on the above. The automatic exchange of chips using a robot is well known and will not be described in detail, but is roughly performed according to the following operation procedure.
1. Move the robot to the replacement position corresponding to the replacement tip
2. Loosening of the fixing bolt (see Fig. 6) of the tip requiring replacement by the nutrunner NR
3. Replacement tip removal required
4). Move the robot to the chip change rack CH and release the need for replacement / grab the new chip
5). Move the robot to the replacement position corresponding to the replacement tip
6). Installation of new replacement chip on mill 1 (installation at the position where replacement chip is required)
7). Tighten the bolt for fixing the new replacement tip with the nutrunner NR
8). Evacuation from mill 1
(15) The robot control device RCL # 2 sends a signal indicating completion of the replacement work or confirmation of the absence of a replacement chip to the robot control device RCL # 1.
(16) The robot controller RCL # 1 that has received this interrupts the normal operation of the robot # 1 and replaces the hand for the mill again.
[0063]
(17) The robot controller RCL # 1 outputs a chuck open signal, opens the chuck to the jig JG, and releases the clamp of the mill 1.
[0064]
(18) The robot controller RCL # 1 causes the robot # 1 to remove the mill 1 from the jig JG.
[0065]
(19) The robot controller RCL # 1 moves the robot # 1 to the front of the milling machine from which the mill 1 has been removed, and attaches the mill 1 to the milling machine # in the reverse procedure to that described above.
[3] Chip inspection procedure and processing
As described in the above (12), the chip inspection operation is such that the robot # 3 is sequentially moved to the inspection position for each chip inspection taught in advance, and the chip inspection is performed one by one at each inspection position. Is executed. Therefore, in this section, (1) preparation of the visual sensor for chip inspection, and (2) the procedure and processing from the start to the end of the chip inspection are shown in FIG. FIG. 12 (an explanatory diagram of calibration of a light projecting unit), FIG. 13 (an explanatory diagram of an inspection method), and FIG.
[0066]
(1) Preparation of visual sensor
1. A mill equipped with a sample of a worn tip is fixed to the tip inspection table TB, and the robot # 3 is moved to take a posture as shown in FIG.
2. The teaching operation panel 55 of the robot controller RCL # 3 is operated to turn on the laser oscillator 12 of the structure light unit SU. Then, the projection direction is adjusted while giving various command values to the galvanometer 14, and a parameter representing the projection direction suitable for the chip inspection is set. If the angle interval in the light projection direction is too wide (or the number of light projections is too small), it is difficult to obtain high detection accuracy. Therefore, an appropriate number of light projections with appropriate intervals within a range that does not decrease is designed. It is preferable.
[0067]
Here, as shown in FIG. 11, parameters are set such that a total of 11 slit lights 101 to 111 are projected so as to mainly cover the flank 6. The parameters are, for example, a command value representing the center in the light projecting direction, an interval, and the number of light projections.
[0068]
The reason for placing importance on the flank 6 when projecting light is that, as described with reference to FIG. 6, the wear portion 8 has a property that the flank 6 is more widely removed than the rake face 7. It is because it is preferable to detect.
[0069]
3. As described above, the calibration of the light projecting unit including the camera 20 and the galvanometer 14 is completed by a known method. Briefly described, for the calibration of the camera 20, there is known a method for obtaining a correspondence between a position on the camera coordinate system and a parameter representing the line-of-sight direction using a dot pattern. Further, for example, a technique as shown in FIG. 12 is used to calibrate the light projecting unit.
[0070]
That is, the same slit light SL is sequentially projected onto two planes PL1 and PL2 whose positions are already known on the workpiece coordinate system Σw set for the robot # 3, and the obtained bright lines L1 and L2 are calibrated cameras. Shoot at 20. If the obtained image is analyzed by the robot controller RCL # 3, the three-dimensional positions of the bright lines L1 and L2 are obtained. This is because the planes PL1 and PL2 are known, and the line-of-sight directions of any two points G1 to G4 on the bright lines L1 and L2 are known, respectively, and therefore the three-dimensional positions of these four points G1 to G4 are known. By calculating the plane on which these four points G1 to G4 ride, the plane of the slit light SL corresponding to the command value given to the galvanometer at that time can be obtained.
[0071]
The above 2. If the calibration is performed for all of the command values (11) set in (1) and the parameters representing the slit light SL are stored, it is more advantageous because it is not necessary to perform interpolation approximation at the time of measurement.
[0072]
(2) Execution of inspection
As shown in the flowchart of FIG. 14, when the CPU 51 of the robot controller RCL # 3 receives the cleaning completion signal from the robot controller RCL # 2 (Yes in step S1), the robot # is moved to the taught first inspection position. 3 is moved (step S2). Then, the light projecting unit of the structure light unit SU is activated, and the light projection onto the chip 3 with the slit light and the photographing with the camera 20 are repeated. 11 frames) is acquired (steps S3 to S4).
[0073]
Since the inspection position is taught so that the camera 20 faces the flank 6 almost directly, if the bright line patterns formed by the slit light projection performed a total of 11 times are shown together, FIG. 13 (b). FIG. 13A shows a case where only the wear part 8 is provided, and FIG. 13B shows a case where the wear part 8 and the chipped-off part 8a coexist.
[0074]
Next, in order to measure the wear / missing amount from the image acquired by repeating Step S3 to Step S4, first, a part or all of the straight lines of the bright lines 101 to 111 (the worn part 8 and the missing part 8a). A three-dimensional position of an appropriate number of points (illustrated by A1 to A8) on the other part) is calculated to obtain a plane (parameter value describing the plane) on which the flank 6 is on (step S5).
[0075]
Next, of the end points Q1 to Q11 (or Q1 ′ to Q11 ′) on the side where wear / chip-out occurs (the side following the rake face 7; the right side of the screen), the bending points P1 to P6 (or P1 ′ to P6 ′). The three-dimensional positions of the end points Q7 to Q11 (or Q7 ′ to Q11 ′) of the bright lines 107 to 111 that do not have a straight line are calculated, and a straight line 9 corresponding to the intersection line of the flank 6 and the rake face 7 is described. Parameter value) is obtained (step S6).
[0076]
Among all the points constituting the bright lines 101 to 111, a point that is not on the plane (flank 6) obtained in step S5 and is farthest from the straight line 9 is obtained, (Step S7). The condition of not being on the plane (flank 6) obtained in step S5 can be determined by comparing the distance to the plane with a minute threshold value. The measurement points thus selected are P1 in the case as shown in FIG. 13A (more precisely, the point that has fallen into the wear portion 8 by the minute threshold value), as shown in FIG. 13B. In the case, it is P2 ′ (more precisely, the point that has fallen into the dropout portion 8a by the minute threshold value).
[0077]
The distance s (or s') between the selected measurement point and the straight line 9 is obtained as an index representing the wear / drop-off amount (step S8), and compared with the reference value s0 representing the allowable limit / The unnecessary is determined and the determination result is stored (step S9). Further, it is confirmed that it is not the final inspection position (step S10), the robot # 3 is moved to the next inspection position (step S11), the process returns to step S3, and the inspection of the next chip is started. Thereafter, Steps S3 to S11 are repeated, and when the chip inspection at the final inspection position is completed (Yes in Step S10), the process proceeds to Step S12, and the inspection results of all the chips (the mounting addresses on the mill of all exchangeable chips are specified). Data) is sent to the robot controller RCL # 2.
[0078]
  The above embodiment and reference examples are as follows:Describes a system for inspecting / changing chips mounted on milling millsHas beenHowever, if the milling machine is replaced with a lathe and the mill is replaced with a cutting tool, a similar description of the system for inspecting / changing the turning tool of the lathe can be obtained.
[0079]
  In addition, the index indicating the wear / chip-off amount of the tip includes the above-described embodiment.In stateD adopted,L or laterVarious things can be adopted outside.
[0081]
【The invention's effect】
  According to the present invention, it is possible to automatically detect the occurrence of wear or chipping of a tip mounted on a machine tool such as a milling machine, a lathe, or a machining center in a non-contact manner. Tool tip inspection is performed with the tool mounted on the machine tool.LineCan be.
[Brief description of the drawings]
[Figure 1]Of the present inventionImplementationStateIt is the principal part block diagram which showed typically the whole structure of the system which concerns.
FIG. 2 is a view showing an installation mode of a camera CM together with an outline of a milling machine body FM and an appearance of a console CS.
FIG. 3 is a diagram showing an image photographed by a camera with respect to a tool tip positioned at one inspection position.
[Fig. 4]Of the present inventionImplementationIn stateIt is the flowchart which described the outline | summary of the process for the abrasion / chip-out test | inspection of the chip | tip performed.
[Figure 5]Reference exampleIt is the principal part block diagram which showed typically the whole structure of the system which concerns on.
[Fig. 6]Reference exampleThe chip used in the milling machine deployed in is an enlarged view of a chip with a worn part.
FIG. 7 is a schematic diagram illustrating a state in which a mill is fixed to a jig on a chip inspection work table.
[Fig. 8]Reference exampleIt is a mimetic diagram explaining the work situation of robot # 2 and # 3 arranged by.
FIGS. 9A and 9B are schematic views illustrating the main structure of a structure light unit, and FIG. 9B illustrating a method of forming a structure light.
FIG. 10Reference example1 is a block diagram illustrating an essential part of a configuration of a built-in image processing apparatus-type robot control apparatus together with an outline of a connection relationship with other elements.
FIG. 11 is a diagram illustrating a structure light projection state with respect to a chip;
FIG. 12 is a diagram illustrating calibration of a light projecting unit.
FIGS. 13A and 13B are diagrams for explaining a method for inspecting chip wear / chip-off, in which FIG. 13A shows a case where only the wear portion is present, and FIG. 13B shows a case where the wear portion and the drop-off portion coexist. .
FIG. 14Reference example5 is a flowchart showing an outline of a process for chip wear / chip-out inspection performed in FIG.
[Explanation of symbols]
  1 Tool (mill)
  1a Tapered part of the mill
  1b Mill head
  2 Convex
  3 chips
  4 Fixing bolt
  5 Bolt hole
  6 flank
  7 Rake face
  8 Wear parts
  8a Missing part
  9 Intersection of flank and rake face
  11 Floodlight window
  12 Laser oscillator
  13 Cylindrical lens
  14 Galvanometer
  20, CM camera
  21 Shooting window
  51 Central processing unit (CPU)
  52 ROM memory
  53 RAM memory
  54 Nonvolatile memory
  55 Teaching operation panel
  56 Digital Servo Circuit
  57 Servo amplifier
  58 Bus
  61 Interface for structure light unit
  62 Image processor
  63 Monitor interface
  64 frame memory
  65 Program memory
  66 Data memory
  67 Communication interface
  101-111, L1, L2 Bright lines
  A1 to A8 Points on the straight line of the bright line
  AG Airsoft
  CH chip exchange rack
  DR door
  FCL, FCL # 1 to FCL # 3 Milling machine controller
  FM milling machine body
  G1, G2 Points on the bright line L1
  Points on G3 and G4 bright line L2
  H Hand changing mechanism
  HD Mill gripping hand
  HL jig mounting hole
  IP image processing device
  IL lighting device
  JG jig
  MO monitor
  NR Nutrunner
  B1 to P6, P1 'to P6'
  PL1, PL2 known plane
  Q1 to Q11, Q1 'to Q11' The end points on the side where wear / chip-out of bright lines occurs
  RCL # 1 to RCL # 3 Robot controller
  RL travel axis
  UL structure light (slit light)
  SP spindle
  SPH spindle head
  SPU spindle unit
  SU structure light unit
  TB chip inspection and exchange work table
  VS visual sensor
  WS1 Raw workpiece supply section
  WS2 machined workpiece storage
  WT work table
  WTH work table head
  Σw Work coordinate system

Claims (4)

A visual sensor means is used to inspect a plurality of tool tips mounted on a tool of a machine tool controlled by a control device for wear and / or chipping while the tool is attached to the machine tool. In the tool chip defect inspection system,
The control device includes means for positioning control of the translation position and the rotation position of the tool so that a plurality of tool tips mounted on the tool sequentially come to predetermined inspection positions,
It said visual sensor means performs a sensing from a predetermined direction for tool tip in the inspection position, and acquires the data of the index representing the size of the defect, the tool tip defect inspection system. A visual sensor means is used to inspect a plurality of tool tips mounted on a tool of a machine tool controlled by a control device for wear and / or chipping while the tool is attached to the machine tool. In the tool chip defect inspection system,
The tool chip defect inspection system is provided with a use accumulated time detecting means for detecting a use accumulated time of the tool ,
The control device performs positioning control of the translation position and the rotation position of the tool so that a plurality of tool tips mounted on the tool sequentially come to predetermined inspection positions based on the output of the use accumulated time detection means. and means for,
The said visual sensor senses the tooltip in the said test | inspection position from a predetermined direction, and acquires the data of the parameter | index showing the magnitude | size of a defect | deletion, The said tooltip defect inspection system characterized by the above-mentioned.   The visual sensor means is a camera means for photographing a tool tip at the inspection position from a predetermined direction, and an analysis of an image acquired by the photographing by the camera means to analyze the size of the defect of the photographed tool tip. The tool tip defect inspection system according to claim 1, further comprising means for acquiring data of an index representing the height. Means for comparing the data of the index representing the size of the defect with a predetermined criterion to determine the necessity of tool tip replacement;
The tool according to any one of claims 1 to 3, further comprising means for notifying a predetermined message when the result of the determination corresponds to the necessity for replacement of the tool tip. Chip defect inspection system.

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