Electric heating – Metal heating – By arc
Reexamination Certificate
2003-06-02
2004-04-20
Heinrich, Samuel M. (Department: 1725)
Electric heating
Metal heating
By arc
C219S121670, C219S121790
Reexamination Certificate
active
06723949
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a laser beam machine for executing cutting machining on a workpiece in the shape of a plate.
FIG. 7
is a view showing how to cut a corner portion according to a conventional machining method wherein (a) is a view showing loop R of movement path, and (b) is a view showing a part of a machining program.
In order to cut a sharp corner formed by crossing straight lines of cut paths with a laser beam machine in a conventional method, for instance, in order to cut a sharp corner formed by crossing cut paths L
1
and L
5
(full line), which are straight lines, at position P
1
(x coordinate is 0, y-axis coordinate is 0) as shown in FIG.
7
(
a
), cut path L
1
is cut in an arrow direction as shown in FIG.
7
(
a
), and thereafter, the sharp corner is cut, circling outside the cut shape along loop R (LR) as shown by a broken line, passing through positions P
1
, P
100
(x coordinate is 5, y-axis coordinate is 0), P
101
(x coordinate is 0, y-axis coordinate is 5) in order, without immediately cutting cut path L
5
. This method is adopted in order to prevent the sharp corner from not being cut in a desired shape for the reason that a workpiece
70
is overheated with laser beam so as to be melted when feed speed F temporarily becomes zero at the time of passing through position P
1
by the torch. This machining method is executed by a machining program PRO which is comprised of a plurality of machining steps PS
1
, PS
2
, . . . , as shown in FIG.
7
(
b
). In the machining program PRO, a loop R program LRP for circling on the above-mentioned loop R (LR) is inserted between machining steps PS, PS
5
.
That is, linear interpolation instruction (G
01
) where feeding speed F is 30,000 mm/min, and end point is position PI is instructed in block N
1
of the first machining step PS
1
of the top in the figure, and linear interpolation instruction (G
01
) of moving 50 mm in a negative direction of y-axis from position P
1
is instructed in block N
5
of the fifth machining step PS
5
of the bottom. And, the above-mentioned loop R program LRP is inserted before block N
5
.
The loop R program LRP is comprised of three blocks N
2
, N
3
, and N
4
of machining steps PS
2
, PS
3
and PS
4
, as shown in FIG.
7
(
b
). In the first block N
2
, linear interpolation instruction (G
01
) of moving 5 mm in a positive direction of x-axis along movement path S
1
to end position P
100
in order to elongate cut path L
1
, maintaining the feeding speed F, is instructed. When a torch reaches position P
100
, arc interpolation instruction (G
03
) of arc R
1
, connecting with both extended lines of cut paths L
1
and L
5
, having 5 mm of radius R determined on the basis of a predetermined acceleration by which the feed speed F can be maintained, is instructed in the second block N
3
. When the torch reaches position P
101
, linear interpolation instruction (G
01
) of moving 5 mm in a negative direction of y-axis along movement path S
2
to end position P
1
in order to elongate cut path L
5
, maintaining the feeding speed F, is instructed in the last block N
4
. When returns to position P
1
, the loop R program LRP finishes, and linear interpolation instruction (G
01
) of moving 50 mm in a negative direction of y-axis is instructed in block N
5
of machining step PS
5
, so as to continue cutting machining along cut shape of cut path L
5
, maintaining feed speed in cut path L
1
.
The torch moves along the loop R (LR) comprised of straight line S
1
, arc R
1
and straight line S
2
, so that cutting machining is possible at the same feed speed F at any position in a cut shape, irrespective of a sharp corner. Therefore, the workpiece
70
can be cut in a desired cut shape by cutting a sharp corner, maintaining a good cut face having no machining irregularity.
In the above-mentioned machining method, it is necessary to move the torch along a movement path which is comprise of a straight line, an arc and a straight line every machining on the sharp corner, so that the time for circling on the movement path at a predetermined feed speed prevents speedy machining. In case where there are many sharp corners to be machined, such as a case where parts having a sharp corner in great number are located on the workpiece
70
(nesting), or such a case where parts to be cut have many sharp corners, the machining efficiency is lowered owing to increased number of circling, and it is further difficult to actualize speedy machining thereby.
Furthermore, it is necessary to insert the loop R program LRP having three blocks according to a straight line, an arc and a straight line every machining block of the sharp corner when producing a machining program. Therefore, longer time is necessary for such insertion, and more specifically, much work is necessary in case where many sharp corners are machined. Besides, program capacity for the loop R program LRP is also necessary according to the number of the sharp corner. More inconveniently, bigger locus of loop R to be inserted into a corner leads to meaningless cutting of a material, and nesting efficiency is lowered thereby.
Under these circumstances, the development of the laser beam machine for cutting a sharp corner on the basis of a desired cut shape, maintaining a good cut face having no machining irregularity, capable of actualizing speedy cutting machining in an easy way, has been desired.
SUMMARY OF THE INVENTION
A laser beam machine of the invention has:
a radiating means for radiating laser beam on a workpiece to be cut;
a means for moving and driving, for moving and driving the radiating means at predetermined feed speed;
a machining execution means for moving and driving the radiating means through the means for moving and driving on the basis of a movement instruction instructed by a machining program;
a sharp corner judgment means for judging as to whether a corner of cut shape in the workpiece is a sharp corner or not on the basis of the machining program;
additional locus producing means for producing sharp corner, for producing additional locus for producing sharp corner when machining a corner which is judged as the sharp corner by the sharp corner judgment means; and
a sharp corner machining execution means for machining the corner judged as the sharp corner on the basis of the additional locus for producing sharp corner produced by the additional locus producing means for producing sharp corner.
According to an aspect of the invention, an additional locus for producing sharp corner is automatically produced when machining on a corner judged as a sharp corner, and the corner is machined on the basis of the additional locus for producing sharp corner. Therefore, the sharp corner can be easily machined, maintaining a good cut face having no machining irregularity without spending longer time for programming for machining. More specifically, in case where there are many sharp corners to be machined, producing of machining program can be further lightened. Besides, more conveniently, it is not necessary to increase program capacity for machining on the sharp corner.
According to an another aspect of the invention, the sharp corner machining execution means can control feed speed of the radiating means so as to move the radiating means, decelerating feed speed from the feed speed before entering into the sharp corner, from passing of the corner till returning to the corner by the radiating means.
In this case, the additional locus for producing sharp corner shorter than a conventional locus can be produced when machining on the sharp corner since the torch moves, reducing feed speed from passage of laser beam on a corner judged as the sharp corner till return to the corner. Then, speedy machining can be realized, maintaining a good cut face having no machining irregularity. In case where there are many sharp corners to be machined, more speedy machining is possible. Besides, meaningless cutting of a material is saved by shortening the locus so as to improve nesting efficiency.
According to an another aspect of t
Inoue Toshihiko
Iryoda Hikaru
Miyagawa Naoomi
Yamazaki Tsunehiko
Duane Morris LLP
Heinrich Samuel M.
Yamazaki Mazak Kabushiki Kaisha
LandOfFree
Laser beam machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Laser beam machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laser beam machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3202386