JP2007331067A - Workpiece measuring instrument of nc machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a workpiece measuring instrument for use in a machine tool, which ensures that an on-off command of power supply for a measuring tool and other information are exchanged via space propagation waves. <P>SOLUTION: Communication between the measuring tool 13 mounted on a working spindle of the machine tool and a plurality of transceiver modules 17a including transmitters 19a and receivers 21a mounted on the ceiling of a splash guard are performed via space propagation waves. When the on-off command of power supply for the measuring tool 13 is required, it is transmitted only after a transmitter selection processing means 27 selects the transmitter closest to the measuring tool 13 out of the transmitters 19a, 19b, and a rotational angle required to turn a receiver 33 of the measuring tool 13 toward the selected transmitter 19a is computed by a working spindle rotational angle operating means 29 and is transmitted to a numerical control device so that rotation positioning of the working spindle is performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a workpiece measuring device for an NC machine tool that measures a reference surface and dimensions of a workpiece using a measuring tool that is detachably attached to a spindle of the NC machine tool.

  Conventionally, there is an apparatus for measuring a workpiece machined by an NC machine tool on the machine. Generally, a measuring tool is mounted on the spindle of a machine tool, the workpiece and the measuring tool are moved relative to each other, and the measuring tool's probe is brought into contact with the surface to be measured to measure the reference surface and dimensions of the workpiece. Is. Patent Document 1 discloses a device that mounts a touch sensor type measuring tool on a spindle of a machine tool, brings a measuring element into contact with a surface to be measured, and transmits and measures the contact signal with a spatially propagated wave. . In Patent Document 2, a measuring tool having a contact displacement type probe is attached to the spindle of a machine tool, the workpiece is measured by bringing the probe into contact with the surface to be measured, and an error inherent to the measuring tool is corrected. An apparatus for obtaining correct measurement values is disclosed.

Japanese Patent Laid-Open No. 9-201744 Japanese Patent No. 3396409

  The prior art described in Patent Document 1 turns on the power of the measuring tool only when performing measurement in order to reduce the power consumption of the battery of the measuring tool, extend the battery life, and improve the efficiency of the automatic measurement work. Thus, the signal of the spatial propagation wave is exchanged. However, in a large machine tool, in order to avoid obstacles such as the shape around the spindle head and the workpiece mounting shape, many transmitters and receivers of spatial propagation waves must be installed. In addition, in order to avoid an obstacle, a signal must be transmitted after the measuring tool is moved to a predetermined position, so that there is a problem that it takes time to exchange the signal. The prior art described in Patent Document 2 corrects the measured value measured with the measuring tool to a correct value. However, there is a problem similar to that of Patent Document 1 described above regarding the exchange of signals of spatially propagated waves. It was. An object of the present invention is to solve the problems of the prior art, and an object of the present invention is to provide an ON / OFF command signal for measuring tool power supply and others in a workpiece measuring apparatus that transmits information using a spatially propagated wave. It is an object of the present invention to provide a workpiece measuring device for an NC machine tool that reliably exchanges information.

  In order to achieve the above-described object, according to the present invention, in a workpiece measuring device for an NC machine tool having three orthogonal feed axes of X, Y, and Z and a rotary feed shaft of a main shaft, a probe is provided at the tip. The body part is provided with a receiver and transmitter for spatially propagated waves, and is provided at an appropriate interval between the measuring tool that is detachably mounted on the spindle of the machine tool and the fixed part of the machine tool structure. A plurality of transmitters for transmitting a spatial propagation wave of information transmitted to the measurement tool, and a plurality of transmitters provided in the vicinity of the transmitter for receiving a spatial propagation wave of information transmitted from the transmitter of the measurement tool When receiving the power ON / OFF command of the measurement tool from the receiver and the numerical control device, before transmitting the power ON / OFF command signal of the measurement tool from the transmitter, the transmitter from the plurality of transmitters Select the transmitter closest to the position of the measuring tool A measurement tool power ON / OFF pre-processing unit that calculates the rotation angle of the spindle necessary for directing the receiver of the measurement tool toward the selected transmitter, and sends the rotation angle to the numerical controller; An NC machine tool workpiece measuring apparatus including the above is provided.

  When the measurement tool power ON / OFF pre-processing unit receives a measurement tool power ON / OFF command from the numerical control device, it selects the transmitter that is closest to the measurement tool position and has good transmission / reception efficiency. The receiver is directed toward the selected transmitter, and then a power ON / OFF command signal for the measuring tool is transmitted.

  According to the present invention, the power ON / OFF pre-processing unit of the measurement tool arbitrarily selects the coordinate value of the current position of the measurement tool on the machine or the measurement tool when receiving the power ON / OFF command of the measurement tool. The coordinate value of the position moved to the position of the position is read, and from the coordinate value of the position of the measurement tool and the coordinate value of the position of the plurality of transmitters, the distance between the measurement tool and each transmitter is calculated, From the transmitter selection calculation means for selecting the transmitter closest to the position of the measurement tool from among the plurality of transmitters, the coordinate value of the position of the measurement tool and the coordinate value of the position of the selected transmitter, the measurement tool NC having a spindle rotation angle calculation means for calculating the rotation angle of the spindle necessary for directing the receiver provided in the direction of the selected transmitter and sending the rotation angle to the numerical controller Provided by machine tool workpiece measuring device It is. Select the transmitter with the highest transmission and reception efficiency that is closest to the position of the measurement tool, calculate the rotation angle of the main shaft to direct the receiver installed on the measurement tool toward the selected transmitter, and rotate the main shaft Then, an ON / OFF command signal for the power supply of the measuring tool is transmitted.

  Further, according to the present invention, the transmitter selection calculation means includes a center value representing a coordinate value of the position of the measuring tool, a coordinate value of the positions of the plurality of transmitters, and a direction in which the transmitter transmits a spatial propagation wave. From the straight line, calculate the length of the perpendicular line from the position of the measuring tool to the central straight line that indicates the direction of transmitting the spatially transmitted wave of each transmitter, and determine the transmitter with the shortest vertical line length. An NC machine tool workpiece measuring device is provided which is selected as the transmitter closest to the position of the measuring tool. Calculate the distance between the position of the measuring tool and the center straight line that indicates the direction in which the transmitter emits spatially propagated waves, select the transmitter with the shortest distance as the transmitter closest to the measuring tool, and select the selected transmitter A power tool ON / OFF command signal is transmitted from the measuring instrument.

  According to the present invention, when receiving a power ON / OFF command of a measuring tool mounted on a spindle from a numerical controller based on an NC program, measurement is performed from among a plurality of transmitters provided in a fixed part of a machine tool. Select the transmitter closest to the position of the tool, rotate and position the spindle so that the receiver provided on the measuring tool faces the selected transmitter, and then turn ON / OFF the command signal of the measuring tool. Since the transmission is made, signals are exchanged between the transmitter and the receiver of the measurement tool in a state where transmission and reception efficiency is good, and the power ON / OFF command of the measurement tool and other information are reliably transmitted. Yes. Therefore, the number of transmitters can be reduced. Conventionally, even in a machine that requires several transmitters, according to the present invention, the number of transmitters is two. In addition, since the transmitter with the shortest distance between the position of the measuring tool and the center straight line indicating the direction in which the transmitter transmits a spatial propagation wave is selected, transmission and reception of information may fail and an alarm may occur. Less. Further, it is not necessary to position the measuring tool at a predetermined position in order to avoid the obstacle of the spatial propagation wave, and the time required for the measurement is shortened.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration block diagram showing an embodiment of the present invention. 1 shows a configuration in which a machine tool 1 such as an NC milling machine or a machining center is driven and controlled by a numerical control device. The NC program 3 is read and interpreted by the reading / interpretation unit 5 of the numerical controller, and program data is sent to the interpolation unit 7. The interpolation unit 7 performs an interpolation operation on the received program data and sends position command data to the servo unit 9. The servo unit 9 sends out an operation command for driving each feed axis of the machine tool 1 based on the received position command data.

  The machine tool 1 has three orthogonal feed axes of X, Y, and Z, and a rotation feed axis of the main shaft. Position detectors 11 are provided on these feed shafts so that X, Y, and Z position data and, if necessary, spindle rotational position data can be detected. A measuring tool 13 is detachably mounted on the spindle of the machine tool 1 and is mounted by a tool changer during workpiece measurement. The workpiece is measured by relatively moving the workpiece attached to the table of the machine tool 1 and the measuring tool 13 attached to the spindle. The measuring unit 15 brings a measuring element provided at the tip of the measuring tool 13 into contact with the surface to be measured of the workpiece, reads position data from the position detector 11 of the machine tool 1 based on the contact signal, and calculates measurement data. To do.

  A plurality of transmission / reception modules 17a and 17b are provided on a fixed portion of the structure of the machine tool 1, for example, on the ceiling of the splash guard or the upper part of the column. The transmitter / receiver module 17a is provided with a transmitter 19a and a receiver 21a as a set in the vicinity. Similarly, the transmitter / receiver module 17b includes a transmitter 19b and a receiver 21b. The transmission / reception modules 17a and 17b are attached at an appropriate interval. In this embodiment, two transmission / reception modules are provided. The transmitter 19a and the receiver 21a transmit and receive spatial propagation waves. For example, the transmitter 19a is an infrared light emitting element, and the receiver 21a is an infrared light receiving element. The transmitter 19a of the transmission / reception module 17a transmits information to the measuring tool 13, for example, a power ON command signal or an OFF command signal of the measuring tool, and the receiver 21a receives information from the measuring tool 13, for example, a measuring tool. Receive a contact signal. When the measurement unit 15 receives the contact signal of the probe transmitted from the measurement tool 13 via the transmission / reception module 17a, the measurement unit 15 calculates a coordinate value from the position data of each feed axis at that time, and creates measurement data. When the measurement unit 15 receives the contact signal, it sends a signal to the servo unit 9 to stop the movement of each feed axis of the machine. These devices and functions described above are described in Patent Document 1 or Patent Document 2 described above, and are generally well-known workpiece measuring devices, so detailed description thereof will be omitted.

  A feature of the embodiment of the present invention is that a measuring tool power ON / OFF pre-processing unit 25 described later is added to the above-described known workpiece measuring apparatus. When the reading / interpreting unit 5 of the numerical controller reads the power ON command or the power OFF command of the measuring tool from the NC program or the macro program for workpiece measurement, the command data is sent to the power ON / OFF preprocessing unit 25. . When the power ON / OFF preprocessing unit 25 receives the power ON command data or the power OFF command data of the measurement tool, the power ON / OFF preprocessing unit 25 before sending the power ON command or the power OFF command to the transmitter 19a or 19b of the transmission / reception module 17a or 17b. The following processing is performed.

  The power ON / OFF preprocessing unit 25 includes a transmitter selection calculation means 27 and a spindle rotation angle calculation means 29. When the power ON command data or the power OFF command data is received, the transmitter selection calculation means 27 reads the coordinate value of the current position of the measuring tool 13 on the machine, the coordinate value of the position of the measuring tool 13 and a plurality of coordinate values. The distance between the measuring tool 13 and each transmitter 19a, 19b is calculated from the coordinate values of the positions of the transmitters 19a, 19b, and the transmitter 19a that is the shortest and closest to the measuring tool 13 is selected. In this case, the measuring tool 13 may be moved to an arbitrary position on the machine, and the transmitter 19a closest to the position may be selected. The spindle rotation angle calculation means 29 selects the receiver 33 (FIG. 2) provided in the measurement tool 13 from the coordinate value of the position of the measurement tool 13 and the coordinate value of the position of the selected transmitter 19a or 19b. The rotation angle of the main shaft necessary for directing the transmitter 19a or 19b is calculated, and the rotation angle is sent to the numerical controller. Then, the numerical controller positions the spindle at the rotational angle position of the input spindle.

  FIG. 2 is a perspective view showing the measurement tool and the transmission / reception module according to the embodiment of the present invention. The measurement tool 13 attached to the spindle 31 of the machine tool 1 and the transmission / reception modules 17a and 17b attached to the ceiling of the splash guard are shown. The measuring tool 13 is provided with one receiver 33 and a plurality of transmitters 35. The receiver 33 is an infrared light receiving element, and the transmitter 35 is an infrared light emitting element. Two transmitters 19a and 19b provided on the ceiling of the splash guard are provided at an appropriate interval so that a spatially propagated wave reaches the entire machining area of the machine tool. The transmitter 19a or 19b propagates the spatially propagated wave in the form of an enlarged cone around the center straight line 37a or 37b representing the direction in which the spatially propagated wave is transmitted. If the receiver 33 of the measuring tool 13 is within the propagation range, the signal can be received. A plurality of receivers 21a and 21b provided in the vicinity of the transmitters 19a and 19b are provided as a set with the transmitters 19a and 19b. The receivers 21 a and 21 b receive information such as a contact signal of the probe transmitted from the measurement tool 13. The receivers 21a and 21b may be provided at an appropriate interval from the transmitters 19a and 19b. In the present embodiment, an example in which infrared rays are used as spatial propagation waves has been described. However, radio waves and ultrasonic waves may be used.

  FIG. 3 is an explanatory diagram of a calculation method of the power ON / OFF pre-processing unit of the measurement tool according to the embodiment of the present invention. The calculation method of the transmitter selection calculation means 27 and the spindle rotation angle calculation means 29 is shown. The transmitter 19a is attached with a transmission direction arrow 37a of a spatial propagation wave. The transmitter 19b is attached with a transmission direction arrow 37b of the spatial propagation wave. The coordinate values of the positions of the transmitters 19a and 19b and the angles of the transmission directions of the arrows 37a and 37b are known and stored. Upon receiving the workpiece measurement start command, the measurement unit 15 reads the coordinate value of the current position on the machine at the center position 39 (main spindle center) of the measurement tool 13 and sends it to the power ON / OFF preprocessing unit 25. The receiver 33 of the measuring tool 13 is usually mounted in the direction of the upward arrow 41. Upon receiving the power ON command data, the transmitter selection calculation means 27 lowers the perpendicular lines La and Lb from the center position 39 of the measuring tool 13 toward the center straight lines 37a and 37b representing the transmission direction of the transmitters 19a and 19b. For each transmitter, the lengths of the vertical lines La and Lb are calculated, and the transmitter with the shortest vertical line is the transmitter most suitable for transmitting and receiving information and is selected as the transmitter closest to the measuring tool. .

  The spindle rotation angle calculation means 29 uses the coordinate value of the center position 39 of the measuring tool 13 and the coordinate value of the selected mounting position of the transmitter 19a to connect the receiver 33 provided on the measuring tool 13 to the direction of the transmitter 19a. That is, the rotation angle A of the main shaft necessary for turning in the direction of the arrow 43 is calculated, and the rotation angle A is sent to the numerical controller. The numerical control device rotates the main shaft by the rotation angle A and directs the receiver 33 of the measuring tool 13 toward the transmitter 19a. Then, the power ON / OFF pre-processing unit 25 sends a power ON command for the measuring tool to the selected transmitter 19a, and the transmitter 19a transmits a power ON command signal.

  At the time of workpiece measurement, in order to increase the measurement accuracy, the measurement is performed in a state where the spindle is indexed to a specific rotational position and the measurement tool 13 is calibrated. For example, the measurement is performed by determining the spindle at a position where the receiver 33 of the measuring tool 13 faces the direction of the arrow 41. Therefore, after turning on the power of the measuring tool 13 with the receiver 33 of the measuring tool 13 in the direction of the transmitter 19a, the spindle is determined at a specific rotational position (the position of the arrow 41), and measurement is performed. Then, the receiver 33 of the measuring tool 13 is directed again toward the transmitter 19a, and then the power supply OFF command signal of the measuring tool 13 is transmitted to turn off the power. By doing so, the power ON / OFF command signal of the measuring tool 13 is reliably transmitted, and other information between the transmitter and the receiver can be reliably transmitted. When calibration is not required, the workpiece measurement is performed with the receiver 33 of the measuring tool 13 facing the transmitter 19a, and after the measurement is completed, a power OFF command signal is transmitted as it is. That's fine.

  If the position of the measuring tool 13 when the power of the measuring tool 13 is turned off is significantly different from the position when it is turned on, or if the position of the measuring tool is greatly changed to avoid an obstacle, the transmitter After the selection calculation and the spindle index angle calculation processing are performed, the signal transmission is assured if the power supply OFF command signal of the measuring tool 13 is transmitted. Of course, even if the position of the measuring tool 13 when the power of the measuring tool 13 is turned off is the same as the position when the measuring tool 13 is turned on, the power source of the measuring tool 13 is calculated after performing the transmitter selection calculation and the spindle index angle calculation processing. The OFF command signal may be transmitted.

1 is a configuration block diagram showing an embodiment of a workpiece measuring device of the present invention. It is a perspective view which shows the measuring tool and transmission / reception module of embodiment of the workpiece | work measuring apparatus of this invention. It is explanatory drawing of the calculation method of the power ON / OFF pre-processing part of embodiment of the workpiece | work measuring apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Machine tool 5 Reading interpretation part 7 Interpolation part 9 Servo part 11 Position detector 13 Measuring tool 15 Measurement part 17a Transmission / reception module 19a Transmitter 21a Receiver 25 Power supply ON / OFF pre-processing part 27 Transmitter selection calculating means 29 Spindle rotation angle Arithmetic means 33 Measuring tool receiver 35 Measuring tool transmitter

Claims (3)

In a workpiece measuring device for an NC machine tool having X, Y, Z orthogonal three-axis feed axes and a main spindle rotation feed axis,
A measuring tool that has a probe at the tip, a receiver and transmitter of spatial propagation waves in the body, and is detachably attached to the spindle of the machine tool;
A plurality of transmitters that are provided at appropriate intervals in a fixed portion of the structure of the machine tool, and that transmit a spatially propagated wave of information transmitted to the measurement tool;
A plurality of receivers that are provided in the vicinity of the transmitter and receive a spatially propagated wave of information transmitted from the transmitter of the measurement tool;
When receiving a power ON / OFF command of the measuring tool from the numerical control device, before transmitting a power ON / OFF command signal of the measuring tool from the transmitter, the position of the measuring tool is selected from the plurality of transmitters. Select the nearest transmitter, calculate the rotation angle of the spindle required to point the receiver of the measurement tool in the direction of the selected transmitter, and turn on the power of the measurement tool that sends the rotation angle to the numerical controller / OFF pre-processing unit,
An NC machine tool workpiece measuring device comprising:   When the power ON / OFF preprocessing unit of the measurement tool receives a power ON / OFF command of the measurement tool, the coordinate value of the current position of the measurement tool on the machine or the position where the measurement tool is moved to an arbitrary position The coordinate value of the measuring tool is read and the distance between the measuring tool and each transmitter is calculated from the coordinate value of the position of the measuring tool and the coordinate value of the position of the plurality of transmitters, and the measurement is performed from the plurality of transmitters. A transmitter provided in the measurement tool is selected from the transmitter selection calculation means for selecting the transmitter closest to the tool position, and the coordinate value of the position of the measurement tool and the coordinate value of the position of the selected transmitter. 2. An NC machine tool according to claim 1, further comprising: a spindle rotation angle calculation means for calculating a rotation angle of the spindle necessary for directing the transmitter in the direction of the transmitter and sending the rotation angle to a numerical controller. Workpiece measuring device.   The transmitter selection calculation means includes a coordinate value of the position of the measurement tool, a coordinate value of the positions of the plurality of transmitters, and a center straight line representing a direction in which the transmitter transmits a spatial propagation wave. Calculate the length of the perpendicular line from the position toward the central straight line that indicates the direction of transmission of the spatially transmitted wave of each transmitter, and transmit the transmitter with the shortest vertical line closest to the position of the measuring tool. The workpiece measuring device for an NC machine tool according to claim 2, which is selected as a tool.

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