JP2010058239A - Machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining method capable of accurately machining a workpiece irrespective of a mounted state of the workpiece. <P>SOLUTION: The machining method sequentially executes: a mounting process to mount the workpiece W on a table 66; a detection process to measure the distance between a laser measurement head 10 attached to a spindle and a surface of the workpiece W on the table 66 using the laser measurement head 10, thereby detecting the position and posture of the workpiece W in three-dimensional space; a calculation process to compare the detected position and posture of the workpiece W with its reference position and reference posture, respectively, to calculate the deviation between the detected position and the reference position and the deviation between the detected posture and the reference posture; and a machining process to relatively move the tool and the workpiece W while correcting the desired destination positions of the spindle and the table 66 both controlled by a numerical control device 68 so as to negate the calculated deviations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a machining method for machining a workpiece by a machine tool including a spindle on which a tool is mounted, a table on which a workpiece is placed, and a feed mechanism unit that relatively moves the spindle and the table.

  For example, as disclosed in JP-A-2003-80426, the machine tool includes a bed, a column disposed on the bed, a spindle head supported by the column, and a horizontal axis by the spindle head. A spindle that is rotatably supported at the center and on which the tool is mounted at the tip, and a table that is disposed on the bed and on which the workpiece is attached are configured.

  The column is movable in a direction perpendicular to the spindle axis in a horizontal plane, the spindle head is vertically movable, and the table is movable in the spindle axis direction. The feed mechanism is moved in each movement direction. A pallet is placed and fixed on the upper surface of the table, and a workpiece is placed and attached on the pallet. The workpiece is fixed on the pallet with a jig.

  In such a machine tool, the column, the spindle head, and the table are moved by the feed mechanism unit, so that the tool and the workpiece are relatively moved to process the workpiece. The work is often attached to and detached from the pallet by an operator.

JP 2003-80426 A

  By the way, as described above, the work is attached to the pallet by an operator or the like. At that time, the work is caused by a mistake in the worker's attachment or a chip is caught between the jig or the pallet and the work. In some cases, the workpiece is not correctly attached, such as being attached in a state deviating from a predetermined attachment state. In such a state, the workpiece cannot be machined with high accuracy.

  However, the above conventional machine tools cannot prevent such inconveniences, and when the workpiece is not correctly attached to the pallet, it is not possible to perform highly accurate machining.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a machining method capable of machining a workpiece with high accuracy regardless of the attachment state of the workpiece.

To achieve the above object, the present invention provides:
A spindle on which a tool is mounted; a table on which a workpiece is placed; a feed mechanism that relatively moves the spindle and the table along three orthogonal directions including the axis direction of the spindle; and the feed mechanism A method of machining the workpiece by a machine tool comprising a numerical control means for controlling and moving the spindle and the table to a preset movement position,
An attaching step for attaching the workpiece onto the table;
A detection step of measuring a distance between the laser measurement head and a workpiece surface on the table using a laser measurement head mounted on the spindle, and detecting a position and orientation of the workpiece in a three-dimensional space;
A calculation step of comparing the detected position and posture of the workpiece with the reference position and reference posture of the workpiece, respectively, and calculating a deviation amount between the detection position and detection posture and the reference position and reference posture;
The present invention relates to a machining method characterized by sequentially executing a machining step of relatively moving the tool and the workpiece while correcting the target movement positions of the spindle and the table so as to cancel the calculated deviation amount.

  According to this invention, an attachment process is first performed. In this attachment process, the work is attached on the table. The attachment of the workpiece may be performed by the worker himself or may be performed using an attachment device or the like.

  Subsequently, a detection process is performed. In this detection step, the distance between the laser measurement head and the workpiece surface on the table is measured using a laser measurement head mounted on the spindle, and the position and orientation of the workpiece in the three-dimensional space are detected. The workpiece surface is, for example, the workpiece upper surface or the workpiece side surface. In measuring the distance between the laser measuring head and the workpiece surface, the entire workpiece upper surface or workpiece side surface is necessarily measured. It is not necessary, and only a part of the region may be measured in order to shorten the measurement time or facilitate the measurement work.

  Next, a calculation process is performed. In this calculation step, the detected position and posture of the workpiece are compared with the reference position and reference posture of the workpiece, respectively, and a deviation amount between the detected position and detected posture and the reference position and reference posture is calculated. The reference position and reference posture of the workpiece are detected if the distance between the laser measuring head and the workpiece surface is measured using the laser measuring head when the workpiece is correctly mounted on the table. It is the position and posture of the workpiece in the three-dimensional space that is assumed to be performed. The shift amount can be calculated by calculating how much the detection position and the detection posture are deviated from the reference position and the reference posture in the parallel movement direction and the rotational movement direction.

  Finally, a processing step is performed. In this machining step, the tool and the workpiece are relatively moved while correcting the target movement positions of the spindle and the table so as to cancel the calculated deviation amount. Thereby, a predetermined process is accurately performed on the workpiece regardless of the mounting state of the workpiece.

  As described above, according to the processing method of the present invention, the distance between the laser measurement head and the workpiece surface on the table is measured using the laser measurement head, and the position and orientation of the workpiece in the three-dimensional space are determined. Since it is detected and compared with the reference position and reference posture, the amount of deviation between them is calculated and the movement position of the spindle and table is corrected. Since the chips bite between the tool or the table and the workpiece, the workpiece can be processed with high accuracy even when the workpiece is not correctly attached to the table. In addition, it is possible to eliminate the work of reattaching the workpiece.

  Further, the measurement is performed using a laser measuring head, and the measurement interval can be set to be very small as compared with the contact-type measuring device, so that measurement can be performed with high accuracy. Furthermore, the measurement can be performed in a considerably short time as compared with the contact-type measuring device.

  Hereinafter, a processing method according to a specific embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view partially showing a schematic configuration of a machining system for carrying out the machining method according to the present embodiment in a block diagram, and FIG. 2 shows a laser type measuring apparatus constituting the machining system. It is sectional drawing which showed schematic structure of the measurement head. FIG. 3 is a block diagram showing a schematic configuration of a data processing device of a laser type measuring apparatus constituting the processing system, and FIG. 4 is a data configuration of data stored in a distance data storage unit of the data processing device. It is explanatory drawing which showed.

  First, the processing system 1 shown in FIG. 1 will be described. The machining system 1 calculates a distance between the machine tool 60 and the surface of the workpiece W, and transmits data related to the calculated distance (distance data) by wireless communication, and is transmitted from the measurement head 10. And a laser type measuring device 5 having a data processing device 40 that receives the distance data by wireless communication and detects the position and orientation of the workpiece W in the three-dimensional space based on the received distance data.

  The machine tool 60 is disposed on a bed 61, a first saddle 62 that is disposed on the bed 61 and is movable in the front-rear direction (Y-axis direction) in a horizontal plane, and the first saddle 62, A second saddle 63 that is movable in the horizontal direction (X-axis direction) in the horizontal plane, a spindle head 64 that is supported by the second saddle 63 and is movable in the vertical direction (Z-axis direction), and an axis line A spindle (not shown) that is supported by a spindle head 64 and is rotatable about an axis parallel to the Z axis and rotated at a tip (not shown) and an axis center (B axis direction) parallel to the Y axis. ) A table 66 that is freely arranged on the bed 61 and is rotatable about an axis center (C-axis direction) parallel to the Z-axis and on which the workpiece W is placed, a first saddle 62, a first 2 Saddle 63 and spindle head 64 in the Y-axis direction, X-axis direction and Z-axis direction The Y-axis feed mechanism (not shown), the X-axis feed mechanism (not shown), the Z-axis feed mechanism (not shown), and the table 66 are rotated in the B-axis direction and the C-axis direction. A B-axis feed mechanism (not shown) and a C-axis feed mechanism (not shown) that are moved and indexed to a predetermined angular position, and a tool changer 67 that exchanges a tool mounted on the spindle with a new tool; And a numerical controller 68 that controls each feed mechanism unit based on the NC program and the like to move the spindle and the table 66 to a predetermined movement position and control the operation of the tool changer 67.

  The bed 61 has a structure in which side walls are erected on both the left and right sides and the back side, and the first saddle 62 is provided on upper portions of the left and right side walls. The table 66 is supported on a side wall on the back side of the bed 61 so as to be rotatable in the B-axis direction. The table 66 is supported by the table main body 66a so as to be rotatable in the C-axis direction. A pallet mounting portion 66b is provided, and a workpiece W is placed on and attached to the upper surface of the pallet P. The workpiece W is fixed on the pallet P by a jig (not shown). The B-axis feed mechanism unit rotates the table body 66a in the B-axis direction, and the C-axis feed mechanism unit rotates the pallet mounting portion 66b in the C-axis direction.

  Although not particularly illustrated, the tool changer 67 includes a tool magazine in which a plurality of tools are stored, and an exchange mechanism for exchanging the tool stored in the tool magazine and the tool mounted on the spindle, In this replacement mechanism, first, after a tool attached to the spindle is pulled out, a new tool is attached to the spindle.

  The measuring head 10 receives a laser oscillator 11 that irradiates the surface of the work W with laser light, and a CCD camera 12 that receives the laser light irradiated from the laser oscillator 11 and reflected by the surface of the work W to generate two-dimensional image data. Then, the prism 13 and the reflecting mirror 14 for guiding the laser beam from the laser oscillator 11 to the surface of the workpiece W, and the laser beam reflected by the surface of the workpiece W are imaged on the imaging surface 12a of the CCD camera 12 (specifically, Is converged as an annular image), two convex lenses 15 and 16, a diaphragm 17 disposed between the CCD camera 12 and the convex lens 16, and two-dimensional image data generated by the CCD camera 12. The distance in the Z-axis direction between the surface and the measuring head 10 (the laser beam irradiation point P on the surface of the workpiece W and the imaging surface 12a of the CCD camera 12) A distance calculation unit 18 for calculating the distance between the distance calculation unit 18, a transmission device (not shown) for transmitting the distance data calculated by the distance calculation unit 18 to the data processing device 40 by wireless communication, a laser oscillator 11, and a CCD camera. 12, a prism 13, a reflecting mirror 14, convex lenses 15 and 16, a diaphragm 17, a distance calculation unit 18, a transmission device, and the like, and a cylindrical housing 19 fixed to the upper end of the housing 19, and the main spindle of the tool And a mounting member 20 having the same shape as the mounting portion.

  The mounting member 20 is formed with a pull stud 20a that is gripped when the mounting member 20 is mounted on the main shaft. The distance calculation unit extracts an annular image of the reflected laser light based on the two-dimensional image data generated by the CCD camera 12, recognizes the diameter of the annular image, and captures the irradiation point P and the image from the recognized diameter. The distance between the surface 12a is calculated.

  The measuring head 10 is configured to be detachable with respect to the spindle of the machine tool 60, and is usually stored in a tool magazine of the tool changer 67, and only when the workpiece W is measured, the changing mechanism. Is attached to the main shaft.

  The data processing device 40 includes a receiving device (not shown) that receives the distance data transmitted from the measuring head 10 by wireless communication, and the numerical control device 68 from the X axis, the Y axis, and the Z axis of the spindle and the table 66. A position data acquisition unit 41 that acquires relative movement position data in the direction, a distance data storage unit 42 that stores the distance data received from the measurement head 10 and the relative movement position data acquired by the position data acquisition unit 41; A data processing unit 43 that detects the position and orientation of the workpiece W in the three-dimensional space based on the data stored in the distance data storage unit 42; the position and orientation of the workpiece W detected by the data processing unit 43; and the workpiece W A deviation amount calculation unit 44 that compares the reference position and the reference posture with each other and calculates a deviation amount between the detection position and the detection posture and the reference position and the reference posture; The shift amounts calculated by the shift amount calculating section 44 and a correction amount setting unit 45 for setting a correction amount based.

  The position data acquisition unit 41 measures the distance between the surface of the workpiece W and the CCD camera 12 (for example, when laser light is emitted from the laser oscillator 11 or the shutter of the CCD camera 12 is released). And the relative movement position data of the table 66 is acquired, and the distance data storage unit 42 obtains the distance data obtained from the measurement head 10 and the numerical control unit 68 as shown in FIG. The relative movement position data thus stored is stored in association with each other.

  Next, a method for machining the workpiece W using the machining system 1 configured as described above will be described. In the following description, it is assumed that a rectangular workpiece W is processed.

  First, the attachment process which attaches the workpiece | work W on the pallet P of the table 66 through a jig | tool is performed. This attachment work may be performed by the operator himself or by an attachment device. The workpiece W may be a workpiece whose upper surface and side surfaces are once machined, or may be an unmachined one.

  Next, a detection step of measuring the distance between the measuring head 10 and the surface of the workpiece W on the pallet P by the laser measuring device 5 and detecting the position and orientation of the workpiece W in the three-dimensional space from the measurement result. I do. Specifically, first, for example, after the table 66 (table body 66a) is rotated and indexed by the feed mechanism unit at an angular position where the upper surface of the pallet P is horizontal, the laser beam is continuously emitted. The measurement head 10 and the workpiece W are relatively moved by the feed mechanism while irradiating the laser beam, and the distance data and the relative movement position data are acquired at regular intervals in the relative movement direction of the measurement head 10 and the workpiece W (see FIG. 5). Thereby, the distance between the upper surface of the workpiece W and the measuring head 10 is measured. Next, the position and orientation of the upper surface of the workpiece W are detected based on this measurement result. Thereafter, after the table 66 (table body 66a) is rotated and indexed by the feed mechanism unit at an angular position where the upper surface of the pallet P is vertical, the four side surfaces of the workpiece W are determined in the same manner as described above. The distance between one side surface and the measuring head 10 is measured, and the position and orientation of the side surface of the workpiece W are detected based on the measured distance (see FIG. 6).

  After this, in order to detect the position and orientation of the remaining three side surfaces, the table 66 (pallet mounting portion 66b) is moved C to the angular position so that the other side surface of the workpiece W is on the upper side. The index may be determined by rotating in the axial direction, and the distance between the side surface and the measuring head 10 may be measured (see FIG. 7). The position and orientation of the upper surface or side surface of the workpiece W are determined by, for example, specifying the contour line (ridge line) of the upper surface or side surface from the measured distance, and determining the upper surface of the workpiece W from the coordinate value of the end point or intersection of the identified contour line. And the position of the side surface can be detected by obtaining the orientation of the upper surface or the side surface of the workpiece W from the direction of the specified contour line. Further, the posture of the workpiece W can be specified by the orientation of the upper surface or the side surface of the workpiece W.

  In addition to the above, for example, as shown in FIG. 8, among the four straight lines constituting the contour line of the upper surface of the workpiece W, the straight lines at a total of four positions near the end portions of the two straight lines intersecting at least. By scanning the laser beam so as to intersect, the distance between the upper surface of the workpiece W and the measuring head 10 is measured, and four points (Q, R, S, U) on the straight line are identified and identified. The position of the workpiece W is detected from the coordinate values of the four points Q, R, S, U, or the plane including the identified four points Q, R, S, U is obtained, and the orientation, that is, the posture of the workpiece W Can also be detected. Further, the position of the workpiece W can also be obtained from the coordinate value of the intersection V of a straight line passing through each of the two points (a straight line passing through Q and R and a straight line passing through S and U). In this case, a total of eight points on the contour line may be specified by scanning the laser light even near the ends of the other two straight lines constituting the contour line. Thus, if the distance is measured at a total of four or eight locations, the measurement time can be shortened and the measurement operation can be facilitated as compared with the case of measuring the entire surface.

  Thereafter, the displacement amount calculation unit 44 compares the detected position and posture of the workpiece W with the reference position and reference posture of the workpiece W, respectively, and detects the difference between the detected position and detected posture and the reference position and reference posture. A calculation step for calculating the deviation amount is performed. The reference position and reference posture of the workpiece W are the distance between the measurement head 10 and the surface of the workpiece W measured by the laser type measuring device 5 when the workpiece W is correctly mounted on the pallet P. This is the position and orientation of the workpiece W in the three-dimensional space that is assumed to be detected. Further, the calculation of the deviation amount is obtained by calculating how much the detection position and the detection attitude are deviated from the reference position and the reference attitude in the parallel movement direction and the rotational movement direction.

  For example, when the workpiece W actually mounted on the pallet P is in a state shifted from the reference mounting state K indicated by the two-dot chain line in the rotational movement direction (see FIG. 9A), the rotational angle amount Δθ is When it is obtained as a deviation amount and is in a state of deviation in the linear movement direction (see FIG. 9B), the parallel movement amounts ΔX and ΔY are obtained as deviation amounts and are in a state of deviation in the floating direction (see FIG. 9). 9 (c)), the rotation angle amount Δθ is obtained as the shift amount.

  Then, after the measuring head 10 mounted on the spindle and the predetermined tool T stored in the tool magazine are exchanged by the tool changer 67, the target movement positions of the spindle and the table 66 so as to cancel the calculated deviation amount. A machining step of moving the tool and the workpiece W relative to each other while correcting the above is performed. In this correction, for example, a correction amount that cancels the calculated deviation amount is set by the correction amount setting unit 45 based on the deviation amount calculated by the deviation amount calculation unit 44, and the correction amount is set based on the set correction amount. This can be implemented by correcting the target movement position. Thereby, regardless of the attachment state of the workpiece W, the workpiece W is processed into a predetermined shape with high accuracy.

  Thus, according to the processing method of the present example, the distance between the measuring head 10 and the surface of the workpiece W on the table 66 is measured by the laser measuring device 5, and the position of the workpiece W in the three-dimensional space is measured. And the position is detected and compared with the reference position and the reference position, the amount of deviation between them is calculated and the movement position of the spindle and table 66 is corrected. The workpiece W can be machined with high accuracy even when the workpiece W is not correctly attached to the table due to an attachment error or a chip biting between the jig or the table 66 and the workpiece W. . In addition, the work for reattaching the workpiece W can be made unnecessary.

  Further, the surface of the workpiece W is measured by the laser type measuring device 5, and the measurement interval can be set very small as compared with the contact type measuring device, so that the measurement can be performed with high accuracy. Furthermore, the measurement can be performed in a considerably short time as compared with the contact-type measuring device.

  As mentioned above, although one Embodiment of this invention was described, the specific aspect which this invention can take is not limited to this at all.

  In the above example, the 5-axis control machine tool 60 is shown as an example of the machine tool, but the structure of the machine tool for machining the workpiece W is not limited at all. Further, the workpiece W to be processed is not limited to a rectangular shape.

It is the perspective view which showed the schematic structure of the processing system for enforcing the processing method concerning this embodiment partially with the block diagram. It is sectional drawing which showed schematic structure of the measurement head of the laser type measuring apparatus which comprises a processing system. It is the block diagram which showed schematic structure of the data processing apparatus of the laser type measuring apparatus which comprises a processing system. It is explanatory drawing which showed the data structure of the data stored in the distance data storage part of a data processor. It is explanatory drawing for demonstrating the distance measurement between a workpiece | work surface and a measurement head. It is explanatory drawing for demonstrating the distance measurement between a workpiece | work surface and a measurement head. It is explanatory drawing for demonstrating the distance measurement between a workpiece | work surface and a measurement head. It is explanatory drawing for demonstrating the distance measurement between a workpiece | work surface and a measurement head. It is explanatory drawing which showed the attachment state etc. of the workpiece | work with respect to a table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing system 5 Laser type measuring apparatus 10 Measuring head 11 Laser oscillator 12 CCD camera 18 Distance calculation part 40 Data processing apparatus 41 Position data acquisition part 42 Distance data storage part 43 Data processing part 44 Deviation amount calculation part 45 Correction amount setting part 60 Machine tool 66 Table W Work P Pallet

Claims (1)

A spindle on which a tool is mounted; a table on which a workpiece is placed; a feed mechanism that relatively moves the spindle and the table along three orthogonal directions including the axis direction of the spindle; and the feed mechanism A method of machining the workpiece by a machine tool comprising a numerical control means for controlling and moving the spindle and the table to a preset movement position,
An attaching step for attaching the workpiece onto the table;
A detection step of measuring a distance between the laser measurement head and a workpiece surface on the table using a laser measurement head mounted on the spindle, and detecting a position and orientation of the workpiece in a three-dimensional space;
A calculation step of comparing the detected position and posture of the workpiece with the reference position and reference posture of the workpiece, respectively, and calculating a deviation amount between the detection position and detection posture and the reference position and reference posture;
A machining method comprising sequentially performing a machining step of relatively moving the tool and the workpiece while correcting the target movement positions of the spindle and the table so as to cancel the calculated deviation amount.

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