Laser processing apparatus with position controller

Details Laser processing apparatus with position controller Laser processing apparatus with position controller

2001-06-05

2004-04-13

Wilson, Allan R. (Department: 2815)

Coherent light generators

Particular component circuitry

For driving or controlling laser

C372S038010, C372S038070

Reexamination Certificate

active

06721343

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a laser processing apparatus such as a laser drilling machine and a laser cutting machine, and more particularly to a laser processing apparatus having a more processing speed.
BACKGROUND OF THE INVENTION
In a electronic component processing and metal plate processing, laser processing such as drilling, cutting and marking is widely practiced. For example, in an electronic component processing, a laser forms an inner via hole (IVH) in an inter-layered connection circuit for a multi-layered printed circuit board (PCB). The laser processing apparatus for the PCB controls the position of a laser light or the PCB and forms holes at specified positions on the PCB.
Recently, as the electronic devices are getting smaller and lighter, high density mounting of electronic components on the multi-playered PCB is accordingly required. As a result, the number of IVHs formed in the multi-layered PCB increases, and a forming-hole speed of the laser processing apparatus for the PCB must further increases to comply accordingly with this increase.
FIG. 12
shows a structure of a conventional laser processing apparatus for a PCB. The apparatus comprises the following components: A laser generator
16
for outputting laser light; A galvano device
15
having a two-axis motor and a mirror mounted on the motor, for positioning the laser light by driving two mirrors reflecting the laser light; A condenser lens
19
for condensing the laser light; a work table
17
for positioning a mounted PCB
20
to be processed by the laser light; And a control unit
14
for controlling the laser generator
16
, galvano device
15
, work table
17
, and the entire processing apparatus.
The control unit
14
includes a laser controller
7
for controlling the laser generator
16
, a galvano controller
9
for controlling the galvano device
15
, a work table controller
5
for controlling the work table
17
, and a main controller
4
for controlling these controllers and for analyzing programs and processing conditions. When a PCB
20
is put on the work table
17
, the work table controller
5
controls the position of the processing table
17
so that the processing position of the PCB
20
may be located beneath the condenser lens
19
. When the work table
17
is positioned at a specified position, the galvano controller
9
controls the position of the galvano device
15
so that the laser light may be emitted to the specified position of the PCB
20
. By this position control, the galvano device
15
drives the two-axis motor and positions the two mirrors at appropriate angles individually. After a waiting time for settling in which the galvano device
15
finishes the positioning, the laser controller
7
sends a laser output command to the laser generator
16
according to the processing conditions (laser pulse width, laser peak value, number of laser pulses, laser frequency, and so on). According to the laser output command, the laser generator
16
generates a laser light
18
. The laser light
18
is reflected by two mirrors of the galvano device
15
, passes through the condenser lens
19
, and is emitted to the PCB
20
. A hole is formed at the irradiation point of the laser light
18
on the PCB
20
. When the laser output is over, in order to drill a next hole, the positions of the galvano device
15
and work table
17
are controlled again. In this manner, holes are formed by the laser light
18
at desired positions on the PCB
20
. The galvano controller
9
controls the position of the galvano device
15
by a predetermined, fixed control method according to an acceleration/deceleration constant, and settling time.
With the fixed control method, acceleration/deceleration constants, and settling time, however, the performance of the galvano device
15
may not be sufficiently exhibited depending on a moving distance. For example, being controlled by a step speed command (no acceleration or deceleration time, at a constant speed), the galvano device
15
may respond to the command after delay due to electrical or mechanical delay. When a high speed command is given for a short moving distance, the motor cannot follow the command completely due to the response delay, or do not exceed the limit acceleration of the galvano device
15
. Therefore, a vibration does not occur in the galvano device
15
. However, when the moving distance is long, the command lasts longer than the response delay, and the galvano device
15
may exceed the limit acceleration and attempt to follow up the high speed command, thereby causing vibration. Therefore, in the control method of using a fixed speed command regardless of the moving distance, the speed command is limited according to the moving distance. The limited speed command is a lower than the capacity of the apparatus when the moving distance is short, and, as a result, the moving time becomes longer for a shorter moving distance.
Increasing a hole density in relation to the recent higher density tends to shorten the hole position interval. The moving distance of the galvano device becomes shorter accordingly, and an increase of a speed in a short moving distance is accordingly demanded. The conventional control method is not enough to induce a speed performance of the galvano device sufficiently for a short moving distance.
SUMMARY OF THE INVENTION
A laser processing apparatus comprises a laser generator for producing laser light, a laser controller for controlling the laser generator, a positioning unit (a galvano scanner) for positioning the laser light, a control method memory for storing the control method optimum to the moving distance of the positioning unit, an acceleration/deceleration constant memory for storing the acceleration/deceleration constant corresponding to the moving distance of the positioning unit, a waiting-for-settling time memory for storing the waiting time for settling corresponding to the moving distance of the positioning unit, and a position controller (a galvano controller) for controlling the positioning unit. The position controller controlling the position with using the optimum control method, acceleration/deceleration constant and waiting time for settling makes the processing apparatus operate at high speed.


REFERENCES:
patent: 5302798 (1994-04-01), Inagawa et al.
patent: 5450202 (1995-09-01), Tisue
patent: 5632913 (1997-05-01), Mori
patent: 5670068 (1997-09-01), Kuriyama et al.
patent: 5719372 (1998-02-01), Togari et al.
patent: 5777294 (1998-07-01), Sugahara et al.
patent: 5969851 (1999-10-01), Clark et al.
patent: 6222870 (2001-04-01), Sousa et al.
patent: 0 426 600 (1991-05-01), None
patent: 61-061123 (1986-03-01), None
patent: 2000-117476 (2000-04-01), None
patent: 2001246484 (2001-09-01), None
patent: 2002040356 (2002-02-01), None

Affiliated with

Also associated with

Rating

Laser processing apparatus with position controller 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 processing apparatus with position controller, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laser processing apparatus with position controller will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3268376