Electric heating – Metal heating – By arc
Reexamination Certificate
2003-01-31
2004-06-15
Elve, M. Alexandra (Department: 1725)
Electric heating
Metal heating
By arc
C219S121830
Reexamination Certificate
active
06750425
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a control apparatus for a three-dimensional laser beam machine having a head structure in which the processing point is not moved when the rotation axis and the attitude axis are rotated, the control apparatus having a function of, based on a nozzle direction vector, displaying an angle of a nozzle in a vertical direction consisting of the Z-axis of an orthogonal coordinate system, and an angle in a horizontal direction when the nozzle direction vector is projected to the XY-plane.
BACKGROUND ART
Hereinafter, the configuration of a three-dimensional laser beam machine that machines a planar or three-dimensional workpiece shape, and that has a structure of a head in which the processing point is not moved when the rotation axis and the attitude axis are rotated (hereinafter, such a head is referred to as unidirectional head) will be described with reference to
FIGS. 6
,
7
, and
8
.
FIG. 6
is a perspective view showing the configurations of axes of a three-dimensional laser beam machine on which a unidirectional head is mounted,
FIGS. 7A and 7B
are enlarged views of a processing head of the three-dimensional laser beam machine on which a unidirectional head is mounted, and
FIG. 8
is a block diagram showing the configuration of the three-dimensional laser beam machine.
In the figures,
109
denotes an attitude axis (hereinafter, referred to as U-axis) which is positioned at the drive end of an arm
111
,
110
denotes a rotation shaft (hereinafter, referred to as W-axis) which is connected to the U-axis
109
, and
108
denotes a Z-axis which is connected to the W-axis
110
. These axes constitute the arm
111
.
The processing head
3
has: the W-axis
110
which is placed at the tip end of a Z-axis bearing
115
, and which can be rotated in a direction of an arrow +&agr; or −&agr; about the Z-axis by a rotary bearing
114
; and the U-axis
109
which is attached to the tip end of the W-axis
110
by an attitude bearing
113
, and which can be rotated in a direction of an arrow +&bgr; or −&bgr; about an axis that is inclined by 45 degrees with respect to the Z-axis. A processing nozzle
4
is attached to the tip end of the U-axis
109
. Since the U-axis
109
is rotated about the axis which is inclined by 45 degrees with respect to the horizontal plane, the angle of the U-axis does not correspond in a one-to-one relationship to the vertical angle at which the processing nozzle
4
is directed.
The reference numeral
113
denotes the attitude bearing which rotates the U-axis
109
by a servo motor SM
5
in the direction of the arrow +&bgr; or −&bgr;, and
114
denotes the rotary bearing which rotates the W-axis
110
by a servo motor SM
4
in the direction of the arrow +&agr; or −&agr;.
The reference numeral
115
denotes the Z-axis bearing which moves the processing head
3
by a servo motor SM
3
in the direction of an arrow Z,
116
denotes a Y-axis bearing which moves the processing head
3
by a servo motor SM
2
in the direction of an arrow Y, and
117
denotes an X-axis bearing which moves a processing table
2
by a servo motor SM
1
in the direction of an arrow X. The servo motors SM
1
to SM
5
are driven by a driving signal from an NC controller
8
. The reference letter P denotes a processing point the position of which is not moved even when the W-axis
110
and the U-axis
109
are rotated.
The reference numeral
105
denotes a laser oscillator which generates a laser beam, and
103
denotes an operation section through which the NC controller is operated.
When laser beam processing is to be conducted by using the thus configured laser beam machine, it is requested in laser beam processing which machines a planar or three-dimensional workpiece shape that the direction and posture of the processing nozzle
4
are always perpendicular to the processing plane in order to maintain the optical axis of the laser beam irradiating the processing plane to be normal to the processing plane. Before conducting processing, therefore, the operator makes the processing point P coincident with a point (hereinafter, referred to as teaching point) on a processing line K of a processing workpiece
9
, and in advance of actual processing conducts a teaching work in which a teaching point satisfying the requirement is input as a teaching data into a program.
During laser beam processing, in accordance with the teaching data, the spot of the laser beam is controlled so as to advance along the processing line K while maintaining the distance of the processing head
3
with respect to the processing workpiece
9
to be constant.
FIG. 9
is a view showing angles of horizontal and vertical components of a unit vector (hereinafter, referred to as nozzle direction vector) in a direction indicated by the processing nozzle
4
from the angles of the W-axis
110
and the U-axis
109
, in a coordinate system (hereinafter, referred to as orthogonal coordinate system) in which the XY plane is defined as a horizontal plane and X-, Y-, and Z-axes are outer products of the other axes or relationships of Y×Z, Z×X, and X×Y are established. The reference numeral
70
denotes a teaching point in an inclined portion of a workpiece, and
71
denotes a line segment formed by the origin O and the teaching point
70
, i.e., the nozzle direction vector.
The reference numeral
72
denotes a point which is obtained by projecting the teaching point
70
onto the XY-plane,
73
denotes a line segment which is obtained by projecting the line segment
71
onto the XY-plane, i.e., a line segment which is formed by the origin O and the point
72
,
74
denotes the X component dx at the processing point
70
,
75
denotes the Y component dy at the processing point
70
,
76
denotes the Z component dz at the processing point
70
, &thgr; denotes an angle &thgr; of the vertical component formed by the line segment
71
and the Z-axis, and &phgr; denotes an angle &phgr; of the horizontal component formed by the line segment
73
and the X-axis. In
FIG. 9
, because of the structure of the processing head
3
, it is known that the nozzle direction vector d is given from the angle &agr; of the W-axis
110
and the angle &bgr; of the U-axis
109
as:
d
=
(
dx
dy
dz
)
=
(
1
2
·
cos
α
-
1
2
·
cos
α
·
cos
β
+
2
2
·
sin
α
·
sin
β
-
1
2
·
sin
α
+
1
2
·
sin
α
·
cos
β
+
2
2
·
cos
α
·
sin
β
1
2
+
1
2
·
cos
β
)
When a polar coordinate system is used, the relationships between the components dx, dy, and dz at the teaching point
70
in FIG.
9
and the angles of the horizontal component and the vertical component are obtained by the following expressions:
cos &thgr;=dz
tan &phgr;=
dy/dx
From the expressions, the angles in the horizontal and vertical directions are obtained.
&thgr;=
a
cos(
dz
)
&phgr;=
a
tan(
dy/dx
)
As described above, the conversion expressions contain an inverse trigonometric function. In the case where only the angle &bgr; of the U-axis
109
is known, it is impossible to read the angle &thgr; of the vertical component by which the processing nozzle
4
is directed.
The above is similarly applicable to the relationship between the W-axis
110
and the angle &phgr; of the horizontal component.
FIGS. 10A and 10B
are views showing an attitude change of the processing head in a teaching process, and processing in which the incident angle of the laser beam is inclined,
FIG. 10A
shows an attitude change of the processing head in a teaching process and in an attitude change corner portion in a three-dimensional laser beam machine having a head structure in which the processing point is not moved when the
Mukae Tomonari
Sawai Hidekazu
Tsukamoto Masaki
Elve M. Alexandra
Mitsubishi Denki & Kabushiki Kaisha
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