JP2008132556A - Overhead dressing method and overhead dressing device for grinding wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dressing method for increasing overhead dressing precision of a grinding wheel. <P>SOLUTION: In this dressing method for overhead-dressing the grinding wheel w by using a single grindstone dressing instrument 2 changing its position due to travel of a non-numerically controlled shaft 22 being not numerically controlled in the right and left directions and fixed to a numerically controlled vertical shaft 4, the non-numerically controlled right and left shafts are moved without moving the numerically controlled vertical shaft in advance to measure straightness S<SB>i</SB>for the vertical shaft at distance between pitches obtained by dividing stroke of the non-numerically controlled right and left shaft by each correction point p<SB>i</SB>, to calculate straightness correction amount ΔS<SB>i</SB>for the distance between pitches, and to start dressing of the grinding wheel by single grindstone dressing by using this straightness correction amount ΔS<SB>i</SB>as the correction amount for the vertical shaft. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an overhead dressing method for a grinding wheel for surface-grinding the surface of a workpiece such as an automobile part, an electrical / electronic equipment part, a mold member or the like, and an overhead dressing apparatus used therefor.

  A method of overhead dressing a grinding wheel supported in a horizontal direction on a rotating shaft with a dressing device capable of moving in a horizontal direction and a vertical (vertical) direction is known (see, for example, Patent Document 1 and Patent Document 2). .

  For example, a single stone dressing device that dresses a grinding wheel by a predetermined dress amount, and a dress interruption to give instructions to perform dressing work when grinding a workpiece (workpiece) with a grinding wheel When the instructions from the instruction means and the dress interruption instruction means are given, the work grinding operation is interrupted, and the grinding wheel is dressed by controlling the left and right and up and down movements of the single stone dressing device. At the same time, there has been proposed and implemented a grinding apparatus comprising a control means for resuming the work grinding work when the dressing work is completed (see, for example, Patent Document 1).

  In addition, a spindle on which a grinding wheel for grinding a workpiece is detachably mounted, and the spindle is rotatably supported, and relative to the workpiece in three orthogonal directions including the axial direction of the spindle. A movable spindle head, a dressing device main body provided to be movable relative to the spindle head in a direction orthogonal to the axial direction of the main shaft, and a perpendicular to the axial direction of the spindle relative to the dressing device main body A dresser support that is rotatably provided in a direction and supports a dresser for dressing the grinding wheel so as to be rotatable. The operation of the dresser dressing the grinding wheel and the grinding wheel During continuous dressing grinding that simultaneously performs the grinding operation of the workpiece, the dresser capable of dressing the grinding wheel with the dresser. A grinding apparatus is also proposed in which the dressing apparatus body is moved to a singing position, and the dressing apparatus body is moved to a retracted position where the dresser and the workpiece do not interfere during normal grinding other than the continuous dressing grinding process. (For example, see Patent Document 2).

  Further, in a position correction method for correcting the position of another axis that undergoes a position change by movement of a non-numeric control axis that is not numerically controlled, a machine coordinate position register that stores a machine coordinate position of the non-numeric control axis; Register update means for updating the machine coordinate position register by a feedback signal from a position detector of the non-numeric control axis, a straightness correction data memory for storing straightness correction data measured in advance, and the machine coordinate position Also, a position correction numerical control device having straightness correction means for reading straightness correction data corresponding to the above and performing straightness correction for correcting another axis whose position changes due to the movement of the non-numeric control axis has been proposed. Yes. (For example, refer to Patent Document 3).

An upgraded version of the above-mentioned position correction numerical control device is sold by FANUC CORPORATION under the product names of “FANUC Series” 30 _i -MODEL A, 300 _i -MODEL A, 300 _is -MODEL A.

JP 2000-135675 A JP 2000-237957 A JP-A-7-104812

  The grinding wheel dressing method described in Patent Document 2 is numerically controlled for both of the two moving directions of the rotary dresser, so that the straightness between the two axes is good and the grinding wheel can be dressed with high accuracy. However, the vertical axis of the dresser (single stone dressing device) that cuts the grinding wheel is numerically controlled by driving the servo motor and ball screw, and the horizontal axis of the dresser (width direction of the grinding wheel) is the hydraulic cylinder drive. If it is a non-numeric control axis, position correction is necessary to eliminate the phenomenon that the position of one axis changes due to the change of the position of one axis that occurs in the machine tool when the movement distance of the axis is large. Since the hydraulic cylinder drive shaft is a non-numeric control shaft, the position correction cannot be numerically controlled.

  In the latter dressing method using a single stone dressing device, since the straightness between the vertical axis of the single stone dressing device and the left and right reciprocating movement axis of the single stone dressing device is low, the processing accuracy of the dressed grinding wheel decreases. There are drawbacks.

  An object of the present invention is to improve the dressing accuracy of a grinding wheel by applying the position correction numerical control device described in Patent Literature 3 to a grinding wheel dressing method using a single stone dressing device.

The invention of claim 1 can be moved in the horizontal direction with respect to the rotary shaft using a single stone dressing device that can be moved in the left-right axis direction by non-numeric control and can be moved in the vertical direction by numerical control. In the method of overhead dressing a wheeled wheel, the left and right axes of non-numerical control are moved in advance without moving the vertical axes of numerical control, and the strokes of the left and right axes of non-numerical control are corrected by the correction points p _i ( _pi is The straightness S _i to the vertical axis at the distance between the pitches divided by an integer of 30 to 1800 is measured and input to the straightness correction amount recording unit of the numerical controller, and the pitch distance is (b−a). From the maximum value S _max and the minimum value S _min of the straightness S _{i at} the pitch distance, the straightness correction amount ΔS _i = (S _max −S _min ) / (b−a) at the pitch distance Straightness correction means Calculating a straightness correction amount [Delta] S _i in each pitch error correction point position in the pitch distance, correcting the dressing amount straightness correction amount [Delta] S _i in the correction point position by sending the recording unit as a correction amount of the vertical axis Then, dressing of the grinding wheel is performed by starting dressing of the grinding wheel by single stone dressing and performing dressing amount dressing by correcting ΔS _{i on} the vertical axis at the pitch error correction point p _i on the horizontal axis. The present invention provides a method for overhead dressing of a car.

The invention of claim 2 is a monolithic dressing device fixed to the vertical axis that can be moved in the left-right axis direction by a hydraulic drive and that can be moved in the vertical direction by a servo motor, straightness correction data S measured in advance. straightness correction data memory for storing _i, the respective correction points p _{i (p i} strokes of the left and right axis without moving the vertical axis by moving the lateral axis of the hydraulic drive non-numeric control of the advance numerical control 30-1800 The straightness S _i to the vertical axis at the distance between the pitches divided by an integer) is measured and input to the straightness correction amount recording unit of the numerical controller, and the distance between the pitches is (b−a). Straightness correction means for obtaining a straightness correction amount ΔS _i = (S _max −S _min ) / (b−a) at the pitch distance from the maximum value S _max and the minimum value S _min of the straightness S _i at , Position detection of the left and right axis And an overhead dressing device having register updating means for updating the vertical axis coordinate position register by a feedback pulse WPf from the device.

  Since the dressing correction amount is determined by approximating the straight displacement amount at each position coordinate between the non-numeric control axis and the numerical control axis, the grinding wheel can be dressed with high accuracy.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1A is a diagram for obtaining a straightness correction amount, and FIG. 1B is a correlation diagram of straightness in the machine coordinate of the moving axis and the pitch error correction point of the moving axis in the straightness correction. FIG. 2 shows the dressing amount from the overhead left end in the width direction of the grinding wheel to the right end through the center, and FIG. 2 (a) is a dressing amount distribution diagram of the grinding wheel dressed at a dress speed of 200 rpm without a dress correction amount. 2 (b) is a dressing amount distribution diagram of a grinding wheel dressed at a dressing speed of 200 rpm, a correction point of 128 points, and a dressing amount of 1 μm. FIG. 2C is a dressing rate of 200 rpm, a correction point of 128 points, and a dressing amount of 2 μm. It is a dressing amount distribution map of a grinding wheel. 3 is a front view of the overhead dressing device with a part cut away, FIG. 4 is a side view of the overhead dressing device, FIG. 5 is a rear cross-sectional view of the overhead dressing device as seen from the direction B-B in FIG. FIG. 7 is a diagram of a dresser amount correction control device, and FIG. 7 is a schematic configuration diagram of a grinding device that performs dresser amount correction.

  3, 4 and 5, 2 is a single stone dressing device, 3 is a single stone diamond, 4 is a ball spline, 5 is a ball screw (vertical axis), 6 and 7 are dogs, 8 is A bearing, 9 is an AC servo motor, 10 is a terminal block, 11 is a pinion gear, 12 is a screwed body, 13 is a motor shaft, 14 is a cover, 15 is an oil cap, and 16 is a motor cover. The ball spline 4 is on the vertical line of the ball screw 5 and is fixed to the screwed body 12. w is a grinding wheel indicated by a virtual line.

  The single stone dressing device 2 fixed to the ball spline 4 is a screwed body that fixes the gear 14 by rotating the gear 14 through the pinion gear 11 fixed to the motor shaft 13 by the rotational driving force of the AC servo motor 9. The ball spline 4 is moved up and down as the ball spline 4 is moved up and down by rotationally driving the ball screw 5 for inserting the 12 internal female screws. When the single stone dressing device 2 moves downward, it can be cut into the outer periphery of the grinding wheel w. The cut amount is controlled by the rotational drive amount of the AC servo motor 9.

  The single stone dressing device 2 is fixed to the slide plate 21 in the downward direction, and the right side of the slide plate 21 is fixed to the front end side of the piston (left and right axis) 22 of the hydraulic cylinder mechanism 20 with a fixing pin 25 via a fixing tool. Then, it slides on the slide base 24 in the left-right direction (grinding wheel width direction). When oil is supplied from a hydraulic pump (not shown) to the rear side of the piston in the hydraulic cylinder 23 via hydraulic pipes 26 and 27 and a solenoid valve (not shown), the slide plate 21 moves forward in the left direction. When the oil is supplied to the front side of the piston, the slide plate 21 moves backward in the right direction. The left-right stroke width of the piston 22 (distance between the single stone diamond dressing device 2 shown by the solid line and the single stone diamond dressing device 2 'shown by the phantom line) is sufficient to be 1.2 to 1.5 times the lateral width of the grinding wheel. .

The mounting plate 28 of the slide base 24 is fixed on the grinding wheel head of the grinding apparatus main body to the grinding wheel head housing 30 in parallel with the grinding wheel axis by using bolts 29 and disc springs 31. 32 and 33 are protective covers.

As can be seen in FIGS. 4 and 5, a position detector scale 40 for reading machine coordinates is attached to the hydraulic cylinder mechanism 20 side of the overhead dressing apparatus 1. The register update means 50 that receives the feedback pulse WPf from the position detector 45 updates the vertical axis 5 and 6 coordinate position registers. In the figure, 41 is a scale cover, 42 is a scale holder cover, 43 is a scale bracket, and 44 is a top.

In the dresser amount correction control device of FIG. 6, the register updating means 50 updates the machine coordinate position register 51 by the feedback pulse WPf from the position detector 45 of the left and right axis 24. Moreover, the straightness correction data memory 53 (64), straightness correction data S _i corresponding to the machine coordinate position of the lateral axis 24 is stored. Straightness correcting means 52 reads the lateral axis of the machine coordinate positions straightness corresponding to the correction data [Delta] Y (corresponding to [Delta] S _i) from straightness correction data memory 53, the vertical axis command value corrected by adding the (dress amount) Yc The vertical axis servo motor 9 is controlled by the command (Yc + ΔY).

As shown in FIG. 1a, the straightness correction data ΔS _i is obtained by moving the hydraulically driven left and right axis 22 without moving the servo motor numerically controlled vertical axes 4 and 5 in advance, and calculating the stroke of the non-numerically controlled left and right axes. The straightness S _i to the vertical axis at the distance between the pitches divided by the number of correction points p _i (p _i is an integer of 30 to 180) is measured and input to the straightness correction amount recording unit of the numerical controller, distance (b-a), straightness correction amount in the inter-pitch distance from the (in Fig. 1a alpha) maximum value S _max of straightness S _i in the pitch distance and a minimum value S _min (in FIG. 1a beta) Let ΔS _i = (S _max −S _min ) / (b−a). In FIG. 1a, ΔS _i = (β−α) / (b−a).

As shown in FIG. 1b, if the horizontal axis of machine coordinates is X _i and the vertical axis is Y _i , a command to move only the vertical axis to pitch points p ₁ to p _i without straightness correction is given. If this is done, the trajectory on the X axis of the single stone dressing device 2 (the trajectory of point A) will be affected by the trajectory of the straightness error on the left and right axes (the trajectory of part B), so that the straightness of the Y coordinate is corrected. I do. When a command for moving only the Y axis (moving axis) to the pitch points p ₁ to p _i is issued, when the B portion is located at p ₁ to p _i , the straightness correction amount corresponding to the straightness correction amount ΔS _{1 is used.} ΔS _i (ε ₁ to ε _{4 in} FIG. 1b) is given to the Y axis. Even if the trajectory of the portion B connecting the X axis and the Y axis is affected by the gradient of the X axis by the correction operation of the Y axis, the trajectory of the point A (single stone dressing device 2) on the Y axis is The effect of the gradient is eliminated.

Straightness correction data ΔS _i creation software is sold by FANUC Corporation under the product names of “FANUC Series” 30 _i -MODEL A, 300 _i -MODEL A, 300 _is -MODEL A. As the grinding wheel width increases, the number of correction points p _i also increases. In the correction points _{p i 30~200, "FANUC Series"} 30 i -MODEL A is used, the correction point number _p i 300 to 1000, is _{"FANUC Series" 300 i -MODEL A} , the correction point number _p i 600 to 2000 "FANUC Series" 300 _is -MODEL A is used. In the grinding wheel dressing, "FANUC Series" 300 _i- MODEL A is sufficient based on the grinding wheel width and the dressing speed of 50 to 300 rpm.

  In the grinding apparatus 60 that performs the dresser amount correction of FIG. 7, the processor 61 controls the entire numerical controller according to the system program stored in the ROM 62. Various data or input / output signals are stored in the RAM 63.

  The non-volatile memory 64 uses a CMOS that is backed up by a battery (not shown), and stores parameters, pitch error correction amounts, grinding wheel correction data, and the like that should be retained even after the power is turned off. The non-volatile memory 64 stores straightness correction data of this embodiment.

  The graphic control circuit 65 converts the digital signal into a display signal and supplies it to the display device 66. As the display device 66, a CRT or a liquid crystal display device is used. The display device 66 displays the shape, machining conditions, the generated machining program, and the like when creating the machining program in an interactive format.

  A machining program can be created by inputting data in accordance with the contents (interactive data input screen) displayed on the display device 66. A graphic representing the meaning of the data is displayed at the top of the screen, and the type of data to be input is displayed at the bottom. In addition, operations or data received on the screen are displayed in a menu format on the screen. Which item to select from the menu is determined by pressing the software key 73 below the menu, and the meaning of the software key 73 changes for each screen.

  The keyboard 67 includes symbolic keys, numerical keys, and the like, and necessary figures and data are input using these keys. A PMC (programmable machine controller) 72 receives an M function signal or the like via the bus 71, processes it with a sequence program, outputs an output signal, and controls the grinding device 60. Further, the PMC 72 receives an input signal from the grinding apparatus side, performs processing by a sequence program, and transfers a necessary input signal to the processor 61 via the bus 71.

  The axis control circuit 68 receives an axis movement command from the processor 61 and outputs an axis command to the servo amplifier 69. The servo amplifier 69 receives this movement command and drives the servo motor of the grinding device 60.

  The grinding device 60 is provided with a preset button 80 on the machine operation panel.

  Returning to FIG. 6, a measurement scale 40 is fixed to the shaft 22, and a position detector 45 is provided facing the measurement scale 40. When the shaft 22 moves, the position detector 45 outputs a feedback pulse WPf corresponding to the amount of movement.

The register update means 50 updates the machine coordinate position of the machine coordinate position register 51 on the left and right axes with this feedback pulse WPf. Moreover, the straightness correction data memory 53, straightness correction data S _i corresponding to the machine coordinate position of the pre-lateral axis is stored.

  The straightness correction means 52 reads straightness correction data corresponding to the machine coordinate position of the left and right axis 22, and sends the straightness correction data to the Y-axis control circuit 68y. The Y-axis control circuit 68y adds straightness correction data ΔY to the Y-axis command Yc, and controls the Y-axis servo motor 9 with the corrected command (Yc + ΔY).

  Further, when returning to the origin, the machine coordinate positions of the left and right axes are preset by the non-numerical control axis preset means 80. Next, the operation of the non-numeric control axis preset means 80 will be described. (Step 1) When the origin return operation is performed manually and the operator presses the preset button 80, a preset signal is sent via the PMC 72, and the non-numeric control axis preset signal is turned on. (Step 2) When the non-numeric control axis preset signal is turned on, the non-numeric control axis preset means 80 presets the machine coordinate position register 51 of the left and right axes to zero. (Step 3) Next, the non-numeric control axis preset means 80 sends an origin return completion signal to the PMC 72, whereby the origin return is completed, and the straightness correction means 52 starts its function.

FIG. 2 shows the commanded correction amount (Yc + ΔY) in the width direction of the grinding wheel corrected for straightness. It is understood that the straightness correction amount ΔY (ΔS _i ) at the center and both ends of the grinding wheel is large.

  Since the dressing correction amount is determined by approximating the straight displacement amount at each position coordinate between the non-numeric control axis and the numerical control axis, the grinding wheel can be dressed with high accuracy.

The figure which calculates | requires straightness correction amount is shown. The dressing amount in the grinding wheel width direction is shown. It is the front view which notched a part of overhead dressing apparatus. It is a side view of an overhead dressing apparatus. It is the back sectional view seen from the BB surface direction in Drawing 3 of an overhead dressing device. It is a figure of a dresser amount correction control apparatus. It is a schematic block diagram of the grinding device which performs dresser amount correction | amendment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Overhead dressing device 2 Single stone dressing device 3 Single stone diamond w Grinding wheel 4 Ball spline 5 Ball screw 9 AC servo motor 20 Hydraulic cylinder mechanism 22 Piston shaft 40 Scale 45 Position detector 50 Register update means 52 Straightness correction means 60 Grinding apparatus 80 preset means

Claims (2)

A grinding wheel mounted horizontally on the rotary shaft overhead using a single stone dressing device that can be moved in the left and right axis direction by non-numeric control and can be moved in the vertical direction by numerical control. a method of dressing, the stroke of moving the lateral axis of the non-numerical control not move the upper and lower axes of advance numerical control non-numeric control lateral axis in each of the correction points p _{i (p i} is an integer of 30 to 1,800) The straightness S _i to the vertical axis at the divided pitch distance is measured and input to the straightness correction amount recording unit of the numerical controller, the pitch distance is (b−a), and the straightness S at this pitch distance is the maximum value of _i S _max and a minimum value S _min straightness correction amount in the inter-pitch distance from the [Delta] S i ₌ each in _{(S max} -S _min) / straightness correcting means (b-a) as a numerical controller In distance between pitches Calculating a straightness correction amount [Delta] S _i in each pitch error correction point position, corrects the dressing amount straightness correction amount [Delta] S _i in the correction point position by sending the recording unit as a correction amount of the vertical axis, then a single An overhead dressing method for a grinding wheel, characterized by starting dressing of a grinding wheel by stone dressing and performing dressing of a dressing amount by applying ΔS _i correction to the vertical axis at a pitch error correction point p _i on the left and right axes . A monolithic dressing device that is movable on the left and right axis by hydraulic drive and fixed on the vertical axis that can be moved in the vertical direction by a servo motor,
Straightness correction data memory for storing straightness correction data S _i measured in advance;
In the pitch distance divided by the correction point number a stroke of the left and right axes of the non-numerical control to move the lateral axis of the hydraulic drive p _{i (p i} is an integer of 30 to 1800) without moving the upper and lower axes of advance numerical control The straightness S _i to the vertical axis is measured and input to the straightness correction amount recording unit of the numerical control device, the distance between the pitches is (b−a), and the maximum value S _max of the straightness S _i at this distance between the pitches. A straightness correction means for calculating a straightness correction amount ΔS _i = (S _max −S _min ) / (b−a) at the pitch distance from the minimum value S _min , and
Register updating means for updating the vertical axis coordinate position register with a feedback pulse WPf from the position detector on the left and right axes;
And an overhead dressing device.

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