Patent Application
20090084235
This application claims the foreign priority benefit under 35 U.S.C. §119 of Japanese Patent Application No. 2007-254305 filed on Sep. 28, 2007, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a jetting apparatus and an origin correction method therefor, and particularly, to a jetting apparatus and an origin correction method for the apparatus that can ensure stable processing accuracy.
2. Description of the Related Art
Water jetting by a jetting apparatus sprays pressurized water at a speed of not less than twice of a sound speed and performs processing. Therefore, because the water jetting can perform shaping such as cutting while avoiding an influence on a property of a work without generating heat, it is suitable for processing a new material, without selecting a material, and the application of the water jetting has been broadened to various fields.
Furthermore, in recent years it becomes required to shorten a processing time, to process a complicated three-dimensional shape, and to achieve high accuracy; a five-axis control processing machine is now sold where a tilt control and a pivot control are added to a conventional three-axis control.
However, compared to the conventional three-axis control, when performing controls of not less than five axes accompanied with an axis rotation control, if there exists any of a nozzle-jet-outlet positional displacement and a nozzle center-axis tilt (angularity), there occurs an error at a position of a processing top point, depending on a rotation angle when a control axis is rotated (tilted or pivoted). Therefore, the five-axis control cannot be considered same as a simple three-axis control (see claims and FIG. 1 in Japanese Patent Laid-Open Publication No. H02-72000). Accordingly, when performing the controls of not less than five axes, there exists a problem that it becomes burdensome to adjust a machine origin position of each axis and that there occurs an accuracy deviation for every operator.
On the other hand, it is difficult to narrow a tolerance range of a nozzle and to ensure accuracy, and there exists a fear that the accuracy varies every time when the nozzle is changed. Therefore, because processing accuracy of the nozzle has to be measured every time when the nozzle is changed, a correction parameter has to be input, based on the measured value of the nozzle, and then a machine origin has to be corrected, there exists a problem that a measurement error occurs and an operation time is longer.
Consequently, there are needs for a jetting apparatus that can ensure stable jetting accuracy, and for an origin correction method for the apparatus.
A first aspect of the present invention is an origin correction method of matching a set processing top point with a machine top point of a sprayed high pressure jet (Jet flow) in a jetting apparatus for spraying the jet on a work from a nozzle, the apparatus having a two-axis angle control for controlling a tilt angle and a pivot angle other than a three-axis control consisting of an X-axis and a Y-axis orthogonalized with each other and a Z-axis of a spray axis line, the method comprising of: a jet radial-runout measurement process of measuring a position of the jet passing through an XY-plane including the machine top point in a state of spraying the jet in a Z-axis direction; a jet radial-runout correction process of calculating an error at the processing top point, based on a deviation between position dada obtained by the jet radial-runout measurement process and the set processing top point, and correcting radial runout of the jet; a jet top-point variation measurement process of changing the tilt angle and measuring two positions, where the jet passes through the XY-plane, in a state of the jet being tilted and sprayed with respect to the Z-axis direction by the angle control; and a jet top-point variation correction process of calculating an error at the processing top point of the jet from position data of the two positions and correcting a deviation of the processing top point.
Thus, the invention sets a processing-top-point parameter from the position data, based on the jet, thereby makes the jet a reference, and corrects a machine origin. The “processing top point” in the jetting apparatus means a top point as a setting value theoretically set by setting a top point parameter (parameter for setting the top point) before a processing start and the like.
That is, by making a jet (pass position and orbit) a reference, and correcting a machine origin, it becomes possible to eliminate an influence of a nozzle size tolerance; therefore, it is possible to maintain jetting accuracy without enhancing a nozzle quality and nozzle size accuracy more than they are conventionally needed.
Furthermore, because a parameter adjustment matched with the spray state of a nozzle finally assembled is performed, it becomes possible to eliminate the influences of various errors and to stably ensure constant processing accuracy without a variation.
Meanwhile, the “machine top point” means a collision point (jet point) where a jet sprayed from a nozzle collides with a work. Furthermore, a distance between the nozzle and the machine top point is preferably set adequately in its value by considering a processing condition, and preferably eliminates an error so that a jet is converged on a constant top point, not depending on a nozzle tilt angle.
A second aspect of the invention is the origin correction method in the jetting apparatus described in the first aspect, and in the radial runout measurement process a position where a center axis of the jet passes through the XY-plane including the machine top point is measured with a transmission laser sensor.
In accordance with the second aspect of the invention, a position where the center axis of the jet passes through the XY-plane including the machine top point is measured with a transmission laser sensor, and thereby because it is possible to detect an edge (outer peripheral point) of the jet, it becomes easy to accurately measure the position of sprayed jet with no contact.
A third aspect of the invention is the origin correction method in the jetting apparatus described in any one of the first aspect and the second aspect; the two-axis angle control consists of the nozzle pivot angle control in the Z-axis and the nozzle tilt angle control in any one of the X-axis and the Y-axis; and in the radial runout measurement process, the nozzle is rotated by the pivot angle control, and a position of the jet is measured in directions along the X-axis and the Y-axis.
In accordance with the third aspect of the invention, the nozzle is rotated by the pivot angle control, and the position of the jet is measured in the directions along the X-axis and the Y-axis, and thereby it is possible to measure deviations of the processing top point in the X and Y directions with respect to the machine top point in the Z-axis.
A fourth aspect of the invention is a jetting apparatus which has a two-axis angle control for controlling a tilt angle and a pivot angle other than a three-axis control consisting of an X-axis and a Y-axis orthogonalized with each other and a Z-axis of a spray axis line, and sprays a high pressure jet on a work from a nozzle, the apparatus comprising: an origin correction controller configured to match a set processing top point with a machine top point of the jet sprayed; and an optical size-measurement device configured to be provided free-rotatably with respect to a table of the jetting apparatus and to measure a pass position of the jet, wherein the origin correction controller performs: a jet radial-runout measurement process of measuring a position of the jet passing through an XY-plane including the machine top point in a state of spraying the jet in a Z-axis direction; a jet radial-runout correction process of calculating an error at the processing top point, based on a deviation between position dada obtained by the jet radial-runout measurement process and the processing top point, and correcting radial runout of the jet; a jet top-point variation measurement process of changing the tilt angle and measuring two positions, where the jet passes through the X-Y plane, in a state of the jet being tilted and sprayed with respect to the Z-axis direction by the angle control; and a jet top-point variation correction process of calculating an error at the processing top point of the jet from position data of the two positions and correcting a deviation of the processing top point.
In accordance with the fourth aspect of the invention, the processing-top-point parameter is set from the measured position data, based on the jet, thereby makes the position of the jet a reference, and it is possible to correct a machine origin and to eliminate the influence of a nozzle size tolerance. Therefore, it becomes possible to maintain jetting accuracy without enhancing a nozzle quality and nozzle size accuracy more than they are conventionally needed.
Furthermore, because a parameter adjustment matched with the spray state of a nozzle finally assembled is performed, it becomes possible to eliminate the influences of various errors and to stably ensure constant processing accuracy without a variation.
In accordance with the jetting apparatus and the origin correction method in the jetting apparatus according to the invention, it is possible to ensure stable jetting accuracy.
Here will be described an embodiment of the present invention in detail with reference to drawings as needed.
A jetting apparatus 1 according to the embodiment of the invention comprises, as shown in
Meanwhile, in the embodiment, as an example of the jetting apparatus 1, although a five-axis-control high-pressure-water cutting apparatus is described where the work W is placed, a table 11 is fixed, and the nozzle 2 is moved, the apparatus 1 is not limited thereto; even a jetting apparatus of a table moving type and comprising angle controls not less than three axes can be applied as the apparatus 1.
Although there exist various ways of taking an Z-axis, a Y-axis, and a Z-axis forming three axes, in the embodiment, as shown in
The nozzle 2 is, as shown in
The nozzle 2 is, as shown in
As exaggeratedly shown in
Here, the machine top point Go exists on an extended line of the jet J actually sprayed from the nozzle 2; whereas, with respect to a processing top point GJ, a top point parameter (parameter for setting a top point) is set, and then a position of the top point GJ is defined.
Therefore, although the processing top point GJ before a change of the nozzle 2 is adjusted at a position (not shown) where the top point GJ matches the machine top point Go, the top point GJ is positioned at a position where the top point GJ is displaced from a present machine top point Go because of the change of the nozzle 2 to another one (see
As the laser sensor 3, as shown in
Meanwhile the laser sensor 3 is not limited to a CCD image sensor system; for example, a scan system is also available which scans a laser beam, calculates a distance from a time of a shade portion formed by the jet J, and obtains position data.
Thus in accordance with the embodiment, the measurement is performed by the transmission laser sensor, and thereby it is possible to detect an edge (outer peripheral point) of the jet J; therefore, it becomes possible to accurately measure the position of the jet J with no contact.
The origin correction controller includes a central processing unit, which consists of a control unit and an operation unit not shown, and a memory, controls a five-axis movement and a high pressure jet supply device (not shown), and operates as follows. Then it is possible to match the processing top point GJ with the machine top point Go of sprayed high pressure jet J (see
An operation of the origin correction controller and each process will be described mainly with reference to
The origin correction controller is configured to perform: a machine-top-point setting process of checking a position of the nozzle 2 and setting in advance the machine top point Go consisting of a machine origin (
Firstly, in order to match positions of the nozzle 2 and the laser sensor 3, when an operator pushes a measurement start button arranged on the operation panel 12, the laser sensor 3 appears, as shown in
In the machine-top-point setting process the nozzle 2 is moved to a measurable point above the laser sensor 3 (see
In the jet radial-runout measurement process, as shown in
Specifically, the C-axis is rotated from −180 degrees to −90 degrees, −0 degree, and +90 degrees for every 90 degrees, and under the four conditions, on the laser sensor 3 are measured center positions Jy (coordinates on the XY-plane) of the jet J, respectively. Then from the measured data of the center positions Jy of the jet J, it is possible to obtain a deviation εy (εy1, εy2, εy3, εy4) in the Y-axis direction at each of the positions Jy.
Here, εy1, εy2, εy3, εy4 indicate the deviation εy in cases of the C-axis being rotated to −180 degrees, −90 degrees, −0 degree, and +90 degrees, respectively (see
Similarly further in the jet radial-runout measurement process, as shown in
Here, εx1, εx2, εx3, εx4 indicate the deviation εx in cases of the C-axis being rotated to −180 degrees, −90 degrees, −0 degree, and +90 degrees, respectively (see
Thus by rotating the C-axis for every 90 degrees and measuring the center positions Jx, Jy of the jet J, it is possible to obtain the deviations εx,εy of the processing top point GJ with respect to the machine top point Go around the C-axis.
Meanwhile, in the embodiment, although the laser sensor 3 is rotated so as to be in parallel to the X and Y-axes, two laser sensors may be arranged so as to be in parallel to the X and Y-axes, respectively.
In accordance with the jet radial-runout correction process, deviations (errors) at the processing top point GJ are obtained from the deviations εx,εy on the X and Y-axes obtained in the jet radial-runout measurement process, and a correction parameter is changed so that the top point GJ matches the processing top point Go (see
At this time, when a center variation (deviations in the X-axis and Y-axis directions) is within a predetermined range value (for example, ±0.05), the jet radial-runout correction proceeds to the next process. On the other hand, when the center variation is not within the range value, the correction parameter is changed, and the jet radial-runout measurement process and the jet radial-runout correction process are repeated.
Thus by repeating the jet radial-runout measurement process and the jet radial-runout correction process and making the deviations within a predetermined range value, it is possible to ensure stable processing accuracy.
In the jet top-point-variation measurement process, as shown in
Meanwhile, in the jet top-point-variation measurement process, a backlash of the C-axis is preferably removed in advance. Therefore, before the A-axis is tilted, for example, the C-axis is rotated by five degrees and then returned, and thus the backlash of the C-axis in the rotation direction is removed. Furthermore, although the A-axis is tilted by −8 degrees and +8 degrees, its tilt angle is not limited thereto; although the angle is preferably set as large as possible, it is possible to appropriately define the angle according to such a specification of a machine.
From the positions (coordinates) Jy (−8 degrees), Jy (+8 degrees) of the jet J thus measured, as shown in
Furthermore, in the jet top-point-variation measurement process, as shown in
From the positions (coordinates) Jx (−8 degrees), Jx (+8 degrees) of the jet J thus measured, as shown in
In accordance with the jet top-point-variation correction process, differences between the deviations εx,εy (variation width) on the X and Y-axes obtained in the jet top-point-variation measurement process and a theoretical variation width from −8 degrees to +8 degrees are calculated, deviations (errors) at the processing top point GJ are obtained, and a correction parameter is changed so that the top point GJ matches the machine top point Go.
At this time, when a center variation (deviations in the X and Y-directions) is within a predetermined range value (for example, ±0.05), the jet top-point-variation correction process proceeds to the next process. On the other hand, when the center variation is not within the range value, the correction parameter is changed, and the jet top-point-variation measurement process and the jet top-point-variation correction process are repeated.
Thus by repeating the jet top-point-variation measurement process and the jet top-point-variation correction process and making the deviations within a predetermined range value, it is possible to ensure stable processing accuracy. Thus setting the origin correction is completed.
Thus in accordance with the origin correction method of the embodiment, based on position data of the jet J (jet flow) measured, a processing-top-point parameter is set from the data, thereby the jet J is made a reference, and a machine origin is corrected.
That is, by making a position, where the jet J passes, a reference, and by resetting the processing-top-point parameter and correcting so that the processing top point Gj matches the machine top point Go, it is possible to eliminate the influence of a nozzle size tolerance; therefore, it becomes possible to maintain jetting accuracy without enhancing a nozzle quality and nozzle size accuracy more than they are conventionally needed.
Furthermore, because a parameter adjustment matched with a spray state of a nozzle finally assembled is performed, it becomes possible to eliminate the influences of various errors and to stably ensure constant processing accuracy without a variation.
Thus although the embodiment of the present invention has been described, the invention is not limited thereto, and may be appropriately changed and practiced.
For example, in the embodiment, although the A-axis and the C-axis are controlled in rotation as a two-axis angle control for controlling a tilt angle and a pivot angle, the embodiment is not limited thereto; the A-axis and a B-axis (rotation axis making the Y-axis direction a rotation center) may be controlled in rotation. In this case, with respect to the B-axis similarly to the A-axis, by tilting the B-axis by −8 degrees and +8 degrees and obtaining radial runout in the processing top point GJ, it is possible to correct the origin position.
In accordance with the jet radial-runout measurement process in the embodiment, from a viewpoint of operation processing, although the C-axis may be rotated from −180 degrees to −90 degrees, 0 degree, and +90 degrees for every 90 degrees and the positions of the jet J are measured, the embodiment is not limited thereto; the C-axis may be rotated by an arbitrary angle as needed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-254305 | Sep 2007 | JP | national |
