JP2006321033A - Drilling machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drilling machine capable of improving drilling speed and having excellent drilling accuracy. <P>SOLUTION: This drilling machine is provided with an X table 7 supporting a workpiece 3 and movable in the horizontal direction on a bed 6, a Y table 107 mounted on a column 17 fixed on an upper surface of the bed 6 and movable in the horizontal direction orthogonal to a moving direction of the X table 7, and a Z table 207 mounted on the Y table 107 and movable in the vertical direction by rotatably supporting a drill 251. The drilling machine performs positioning of each table 7, 107 and 207 by imparting a position command signal to each table 7, 107 and 207, and drills a hole in the workpiece 3 by the drill 251. The drilling machine is provided with an acceleration detecting device 18 to detect acceleration of the X direction of any one of a column 17, the bed 6 or the X table 7. A frequency component fixed in advance is taken out from an acceleration signal of the X direction detected by the acceleration detecting device 18, and a compensation value proportional to the size of the frequency component is fed back to a driving part for driving the X table 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drilling machine that includes a horizontal moving unit that is movable in a horizontal direction and a moving unit that is movable in a vertical direction, and that moves a workpiece and a tool relatively to process a hole in the workpiece.

  For example, a drilling machine that drills a printed circuit board using a drill is mounted on an X table that can move horizontally on the bed and a portal column fixed on the top surface of the bed. A Y table that is movable in the horizontal direction perpendicular to the moving direction of the X table and a Z table that is placed on the Y table and is movable in the vertical direction are provided. A spindle for rotating the workpiece is placed on the Z table, and the workpiece and the drill are moved relative to each other in the directions of the three axes to form holes in the workpiece.

  FIG. 4 is a block diagram of a conventional X table positioning control system.

  The adder 20 calculates a deviation between the position command signal 51 and the X table position signal detected by the X table position detector 16, and outputs the obtained deviation to the X axis position control unit 21. The X-axis position control unit 21 performs control calculation such as PID control based on the input deviation and outputs it to the adder 22 as a speed signal.

  The X-axis differentiator 25 differentiates the detection value output from the X-axis motor rotational position detector 19 to obtain the rotational speed of the X-axis motor, and multiplies the coefficient determined by the ball screw lead by a coefficient unit (not shown). Then, the speed is converted to the speed of the X table and output to the adder 22 as a speed signal.

  The adder 22 calculates a deviation (speed deviation) between the speed signal output from the X-axis position controller 21 and the speed signal output from the X-axis differentiator 25, and uses the obtained deviation as the X-axis speed controller. To 23.

  The X-axis speed control unit 23 performs control calculation such as PID control based on the input deviation, and outputs it to the X motor driver 13 as an X-axis torque command signal 37. The X motor driver 13 performs torque control based on the X axis torque command signal and drives the X axis motor 11 to position the X table 7.

  The Z table or Y table is controlled in the same manner as the X table.

  Next, an example of the drilling operation will be specifically described.

  FIG. 5 is a diagram showing an example of the time history of the speed command values of the X table and the Z table with the speed command value on the vertical axis and the time on the horizontal axis. The upper row is for the X table, and the lower row is for the Z table. It is. The Y table operates at the same timing as the X table.

  The X table is accelerated at a constant torque (speed increases linearly) from time t0 to time t1, and is decelerated (speed decreases linearly) from time t1 to time t2. At time t2, the X table is positioned at the target position.

  From time t2 to time t3 when positioning of the X table is completed, the Z table is accelerated with a constant torque to lower the drill, and from time t3 to time t5, the acceleration is made zero and the drill is lowered at a constant speed. At any time from time t3 to time t5, for example, at time t4, the tip of the drill reaches the printed circuit board, drilling is started, and drilling is completed by time t5. From time t5 to time t6, the Z table is accelerated in a rising direction with a constant torque, and from time t6 to time t7, it is decelerated with a constant torque. At time t7, the Z table is positioned at the target position (in this case, the standby position).

  One drilling is completed by the operation from time t0 to time t7. Then, the movement of the X table to the next drilling position is started from time t7, and the next drilling is completed at time t8.

  As described above, the X table and the Z table perform the drilling operation while repeatedly moving and stopping the rapid acceleration / deceleration pattern.

  In general, when the movement times of the X table and the Z table are compared, the movement time of the Z table is longer. Therefore, if the movement time of the Z table is shortened, the machining efficiency can be effectively improved.

  Since the speed when the drill is lowered is determined by the drill diameter and the number of spindle rotations for obtaining good machining quality, it is necessary to increase the acceleration when the drill is raised in order to shorten the movement time of the Z table.

  However, when the Z table is moved at a large acceleration, the drilling machine generates an excitation force in the vertical direction that is a magnitude obtained by multiplying the mass of the Z table and the spindle mounted on the Z table by the acceleration. . Since the point of application of this excitation force is off the center of gravity of the drilling machine, the flooring rigidity and drilling process are applied to the drilling machine by the moment force determined by the distance between the center of gravity and the application point and the excitation force. Rotational vibration (rocking vibration) having a natural frequency determined by the rotational inertia of the machine occurs. The bed vibrates due to this rocking vibration. When the position of the X table is shifted due to vibration, the control device attempts to return the X table to the designated position. However, since there is a delay, the X table cannot return immediately, so that when the drill comes off the substrate, the drill interferes with the substrate and the shape of the hole collapses, and the processing accuracy decreases.

  As a means for preventing the deterioration of the positioning control performance of the X table, an X table positioning control system (hereinafter referred to as “X-axis positioning control system”) that is less affected by the suppression of rocking vibration or the movement of the Z table can be considered. .

  For example, as a technique for suppressing rocking vibration, a technique has been proposed in which a movable object is moved in a direction completely opposite to the moving direction of the table to reduce the excitation force applied to the apparatus due to the movement of the table (Patent Document 1). .

Also, the reaction force applied in the Z-axis direction (bonding head part) due to the acceleration when the XY stage moves in the XY-axis direction, the distance between the center of the rotating shaft and the center of gravity of the bonding arm, the mass of the bonding arm, and the XY stage Positioning of the bonding head that is calculated based on the acceleration when moving in the XY axis direction, and the reaction force applied to the bonding head drive system is canceled by giving the obtained reaction force as a feedforward amount to the bonding head drive system. A wire bonding apparatus including a control system has been proposed (Patent Document 2).
JP-A-5-234865 JP 2002-134549 A

  A punching machine is usually provided with 5 to 6 Z tables. For this reason, if the technique of patent document 1 is employ | adopted and a movable object is provided in the same number as a Z table, a drilling machine will become expensive and the whole apparatus will become large, and it is not practical.

  If the apparatus configuration is relatively simple, it is possible to reduce the positioning accuracy by moving the Z table by employing the technique of Patent Document 2. However, when the apparatus configuration is complicated like a drilling machine, the calculation error of the feedforward amount becomes large, so that the positioning accuracy cannot be improved.

  An object of the present invention is to provide a drilling machine that can improve the processing speed and is excellent in processing accuracy.

  In order to achieve the above object, the present invention provides an X table that supports a workpiece and is movable in a horizontal direction on a bed, and is placed on a column fixed to the upper surface of the bed. A Y table that is movable in a horizontal direction perpendicular to the moving direction, and a Z table that is placed on the Y table and supports a tool rotatably and is movable in the vertical direction. A position command signal is given to each table to position each table, and an acceleration in the X direction of the column, the bed, or the X table is detected in a drilling machine that drills holes in the workpiece with the tool. Detecting means for extracting a predetermined frequency component from the acceleration signal detected by the detecting means, and calculating a compensation value proportional to the magnitude of the extracted frequency component; Characterized by feedback to the driver for driving the X table.

  Since the influence of the movement of the Z table on the positioning of the X table can be reduced, the Z table can be moved at a high speed, and the machining speed and machining accuracy can be improved.

  Hereinafter, the present invention will be described based on illustrated embodiments.

  FIG. 1 is a side view of a drilling machine according to the present invention.

  The bed 6 of the drilling machine 2 is supported on the floor 1 via the leveling bolt 5 and the block member 4. A rail 9 of the linear guide 15 is fixed to the upper surface of the bed 6.

  The X table 7 is fixed to the slide unit 8 of the linear guide 15 and is movable in the horizontal direction (X direction) in the figure. A ball nut (not shown) held by the X table 7 is screwed into the ball screw 10. The ball screw 10 is driven by an X-axis motor 11.

  The X-axis motor 11 is driven by the X motor driver 13 based on a control signal output from the X table drive controller 12.

  The X table drive controller 12 receives the position command signal 51 output from the operation controller 50, the X table position signal detected by the X table position detector 16, and the acceleration detector 18 attached to the column 17. The X table 7 is positioned based on the acceleration in the X direction (left and right direction in the drawing) of the output column 17 and the detection signal of the X axis motor rotation position output from the X axis motor rotation position detector 19. This constitutes a so-called positioning control system.

  The operation controller 50 outputs a switch opening / closing command signal 53 for opening / closing a switch to be described later to the X table driving controller 12 in order to control whether or not the output signal output from the acceleration detector 18 is adopted.

  The rail 109 of the linear guide 115 is fixed to the column 17 fixed to the upper surface of the bed 6.

  The Y table 107 is fixed to the slide unit 108 of the linear guide 115 and is movable in the Y direction perpendicular to the paper surface. A ball nut (not shown) held by the Y table 107 is screwed into the ball screw 110. The ball screw 110 is driven by a Y-axis motor (not shown). Further, the Y table 107 also constitutes a positioning control system in the same manner as the X table 7 by a Y table driving controller (not shown).

  Then, by moving the X table 7 and the Y table 107, the drill 251 can be positioned at an arbitrary position in the horizontal direction of the printed circuit board 3 on the X table.

  The rail 209 of the linear guide 215 is fixed to the Y table 107. The Z table 207 is fixed to the slide unit 208 of the linear guide 215 and is movable in the vertical direction (Z direction) in the figure. A ball nut (not shown) held by the Z table 207 is screwed into the ball screw 210. The ball screw 210 is driven by a Z-axis motor 211.

  The Z-axis motor 211 is driven by the Z motor driver 213 based on a control signal output from the Z table drive controller 212.

  The Z table drive controller 212 positions the Z table 207 based on the position command signal 52 output from the operation controller 50 and the Z axis motor rotation position detection signal output from the Z axis motor rotation position detector 219.

  A spindle 250 is placed on the Z table 207, and a drill 251 is rotatably held at the tip of the spindle 250.

  The operation controller 50 controls the operation sequence of the X, Y, and Z tables and the spindle.

Note that a plurality (2 to 6) of Z tables may be placed in the Y direction on the Y table 107.
Next, the positioning control system will be described.

  FIG. 2 is a block diagram of the X-axis positioning control system according to the present invention.

  The adder 20 calculates a deviation (position deviation) between the X-axis position command signal 51 output from the operation controller 50 and the position signal output from the X-table position detector 16, and calculates the obtained deviation as the X-axis. Output to the position control unit 21.

  The X-axis position control unit 21 performs control calculation such as PID control based on the input deviation and outputs it to the adder 22 as a speed signal.

  The X-axis differentiator 25 differentiates the detection value output from the X-axis motor rotational position detector 19 to obtain the X-axis motor rotational speed, and multiplies the coefficient determined by the lead of the ball screw 10 by a coefficient unit (not shown). Then, the speed is converted to the speed of the X table 7 and output to the adder 22 as a speed signal.

  The adder 22 calculates a deviation (speed deviation) between the speed signal output from the X-axis position controller 21 and the speed signal output from the X-axis differentiator 25, and uses the obtained deviation as the X-axis speed controller. To 23.

  The X-axis speed control unit 23 performs control calculation such as PID control based on the input deviation, and outputs it to the adder 24 as an X-axis torque command signal 70.

  The adder 24 calculates the difference between the X-axis torque command signal 70 and the signal 29 (torque signal) output from the acceleration feedback compensator 30, and uses the value as a new X-axis torque command signal for the X motor driver 13. Output to. The X motor driver 13 performs torque control based on the X axis torque command signal output from the adder 24 and drives the X axis motor 11 to position the X table 7. Details of the acceleration feedback compensator 30 will be described later.

  First, an example of a measurement method and an example of a measurement result of the influence of the movement of the Z table on the X-axis positioning control system will be described.

  Prior to the measurement, a switch 28 described later is opened in order to stop the operation of the acceleration feedback compensator 30.

  Since the measurement is performed with the X table 7 stopped (stopped), 0 is output as the position command value of the X table 7 to the adder 20 of the X axis positioning control system during the measurement.

  In this state, that is, in a state where the X table 7 is controlled so as not to move from a certain position, a position command value of a sine wave is input as the position of the Z table 207 to the Z axis positioning control system by a frequency analyzer (not shown). . Then, the frequency of the sine wave is swept, the Z-axis torque command signal TZ and the X-axis torque command signal TX output from the Z-axis speed control unit are taken in, and the frequency response characteristic G (s) = TX (s ) / TZ (s) is calculated.

  FIG. 3 is a diagram showing an example of measurement results, with the horizontal axis representing the frequency ω and the vertical axis representing the gain G.

  As shown in the figure, when the Z table 207 moves, the frequency that most affects the X-axis positioning control system, that is, the most moved X table 7 is ω1.

  Therefore, by extracting the frequency ω1 component from the acceleration signal and correcting the position of the X table 7 according to the magnitude of the extracted signal, the influence on the X axis positioning control system when the Z table 207 moves can be reduced. it can.

  Next, the acceleration feedback compensator 30 in FIG. 2 will be described.

  The acceleration feedback compensator 30 inputs the acceleration signal in the X-axis direction of the column 17 detected by the acceleration detector 18 to the bandpass filter 61 and extracts the frequency ω1 component. Then, the signal is output as a signal 29 to the adder 24 via the phase compensator 26 for setting an appropriate phase to suppress the vibration of the X axis, the coefficient unit 27 which is a compensation gain setting unit, and the switch 28. .

  Here, if the signal 29 is input to the adder 24 while the X table 7 is moving, the response of the X table 7 may be affected. Therefore, the contact of the switch 28 is closed only when the Z-axis speed command 52 is not 0 by the switch open / close signal 53 from the operation controller 50, and the signal 29 is input to the adder 24.

  As a result, the force applied to the X table 7 in the stopped state due to the movement of the Z table 207 is cancelled, so the X table 7 does not move.

  Although the acceleration detector 18 is arranged in the column 17 here, the acceleration detector 18 is arranged on the X table 7 or the bed 6 to detect the acceleration in the X direction of the X table 7 or the bed 6, and the detected acceleration is obtained. You may make it input into the acceleration feedback compensator 30. FIG.

  As described above, the drilling machine according to the present invention suppresses the generated vibration by acceleration feedback, so that the X-axis positioning performance is improved and good machining accuracy can be obtained. Further, since the movement of the Z table 207 can be speeded up, the processing speed can be improved.

  When a plurality of Z tables 207 are provided, for example, all the Z tables 207 may be moved simultaneously during measurement.

1 is a side view of a drilling machine according to the present invention. It is a block diagram of the X-axis positioning control system which concerns on this invention. It is a figure which shows an example of a measurement result. It is a block diagram of the conventional X table positioning control system. It is a figure which shows an example of the time history of the speed command value of X table and Z table.

Explanation of symbols

3 Work 6 Bed 7 X table 17 Column 18 Acceleration detector 107 Y table 207 Z table 251 Drill

Claims (2)

An X table that supports a workpiece and is movable on a bed in a horizontal direction, and a Y table that is placed on a column fixed to the upper surface of the bed and is movable in a horizontal direction perpendicular to the movement direction of the X table. And a Z table mounted on the Y table and rotatably supporting a tool and movable in the vertical direction, and a position command signal is given to each of the tables to position the tables. In the drilling machine that processes holes in the workpiece with the tool,
A detecting means for detecting an acceleration in the X direction of any of the column, the bed or the X table;
A predetermined frequency component is extracted from the acceleration signal detected by the detection means, and a compensation value proportional to the size of the extracted frequency component is fed back to a drive unit that drives the X table. Processing machine. The drilling machine according to claim 1, wherein the predetermined frequency component is a frequency at which the driving force of the Z table moves the X table most.

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