Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
2000-12-07
2003-04-01
Tran, Khoi H. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C029S720000, C029S729000, C198S464100, C414S222020, C414S222070
Reexamination Certificate
active
06542786
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for feeding electronic components such as semiconductor chip components to a mounting instrument, especially to said apparatus for feeding electronic components in which a plurality of tape cassettes mounted laterally on a slide base move on a slide platen.
2. Prior Art
One of the typical designs of the conventional electronic component feeding apparatus includes cassette bases for carrying a plurality of tape cassettes laterally oriented, and a slide platen for moving the cassette bases along its longitudinal direction. In this design, conventional ball-screw (ball-thread) mechanism is adopted for moving a selected cassette base to a position for component feeding.
However, the ball-screw mechanism had its limitation in moving the cassette bases with optimal high speed.
Then, the speed of moving the cassette base was improved by the introduction of linear motor as a driving mechanism inserted between the cassette base and the slide platen (Japanese patent laid-open publication No. Sho 61-239696).
The linear motor of the aforementioned development comprises a pair of stationary members attached to the slide platen and a moving member attached to the bottom surface of the cassette base, and is configured such that the moving member is sandwiched between the two stationary members in the pair. The stationary member consists of a plurality of magnets aligned along the longitudinal direction of the slide platen, and the moving member consists of a core made of magnetic material and coils wound around the core for cooperating with the magnets.
Although the high-speed transportation of the cassette base was achieved by the introduction of linear motor described above, the current electronic component feeding apparatus still has another issue to be taken care of. That is, the system is not optimized for handling the variation of the load of the cassette base (the total weight of the cassette base), as the linear motor is driven by so called direct-drive mechanism.
More specifically, the linear motor is not equipped with an acceleration/deceleration mechanism using gears and the like, thus making it impossible to adjust to the variation of the load of the cassette base.
As a result, a constant control gain is used in the circuitry controlling the operation of the linear motor regardless of the load of the cassette base. Thus, when the gain is adjusted to a maximum load for attaining fast setting time of the cassette base to a position for component feeding, the motor may subject to an abnormal vibration at a minimum load condition. Likewise, when the gain is adjusted to a minimum load for preventing the abnormal vibration of the motor, the position setting at the maximum load condition suffers from excessive undershooting and takes more time than desired before settling at the position for component feeding.
So far, the solution to the problem described above is to set the gain at a point somewhere in the middle of the maximum and minimum load conditions. Though this could prevent extreme cases of the problems described above, the operation still suffers from the motor vibration at a minimum load condition and the slow position setting at a maximum load condition, resulting in a longer setting time.
What are needed are an apparatus and a method for feeding electronic components in which the cassette base is transported by the linear motor with a proper control gain adjusted to respective load weight of the cassette base.
SUMMARY OF THE INVENTION
The apparatus for feeding electronic components of the present invention includes, as shown in
FIG. 3
, at least one unit base
12
capable of carrying at least one component feeding unit
13
, a slide platen
11
for sliding the unit base
12
thereon, and a linear motor
14
comprising at least one stationary member
47
a
,
47
b
mounted on the slide platen
11
through a supporting base
44
,
45
for each of the stationary members
47
a
,
47
b
and a moving member
48
mounted on the unit base
12
, which is used to move the component feeding unit
13
. The apparatus also includes, as shown in
FIG. 5
, a motor driver
61
for driving the linear motor
14
, a memory device
66
for storing data for controlling the linear motor
14
, and a control device
67
for controlling the motor driver
66
using the data stored in the memory device
66
, in such a way that the control device
67
adjusts the data for controlling the linear motor
14
based on a load weight of the unit base
12
carrying the component feeding units
13
. In this configuration, the component feeding units
13
mounted on the unit base
12
moves to a predetermined position for feeding the electronic components stored in the component feeding unit, under the control of the control device
67
using the data for controlling the motor
14
, which is adjusted based on the load weight of the unit base
12
. Although the load weight of the unit base
12
may vary depending on the load of the component feeding units
13
which the unit base
12
carries at a certain time during the production operation, a proper operation of the linear motor
14
is assured as the data for controlling the motor
14
is adjusted based on the load weight of the unit base
12
at that time.
Furthermore, the method of feeding electronic components of the present invention utilizes, as shown in
FIG. 3
, at least one unit base
12
capable of carrying at least one component feeding unit
13
, a slide platen
11
for sliding the unit base
13
thereon, and a linear motor
14
comprising at least one stationary member
47
a
,
47
b
mounted on the slide platen
11
through a supporting base
44
,
45
for each of the stationary members
47
a
,
47
b
and a moving member
48
mounted on the unit base
12
, which is used to move the component feeding unit
13
. The method includes, as shown in
FIG. 5
, moving the component feeding units
13
, carried by the unit base
12
, based on the data for controlling the linear motor
12
stored in a memory device
66
, in such a way that a control device
67
adjusts the data for controlling the linear motor
14
based on a load weight of the unit base
12
carrying the component feeding units
13
. As described above, this method assures a proper operation of the linear motor
14
by adjusting the data for controlling the linear motor
14
based on the load weight of the unit base
12
.
In an embodiment of the present invention, the motor driver
61
includes, as shown in
FIG. 5
, a position control unit
63
for receiving driving command for the linear motor
14
, a velocity control unit
64
for receiving output signal from the position control unit
63
, and an electric current control unit
65
for receiving output signal from the velocity control unit
64
and for feeding output signal to the linear motor
14
. The data for controlling the linear motor
14
, which is adjusted based on the load weight of the unit base
12
, may be any form of control loop gain of a feed back system, such as the ones shown in
FIG. 5
for the control units. In particular, a velocity loop control gain of the velocity control unit can be used as the data which is adjusted based on the load weight of the unit base
12
.
In other embodiment, the data for controlling the linear motor
14
is obtained from the total weight ratio to motor weight (inertia ratio) J, which is obtained from the load weight of the unit base
12
carrying the component feeding units
13
. The load weight is obtained from thrust force, which is obtained from the electric current of the linear motor
14
during a tuning operation. The tuning operation is performed by moving the unit base
12
for a predetermined distance while the unit base
12
carrying the component feeding units
13
moves from a home position to the position for component feeding. The tuning operation may be performed at the time of system activation by turning on the power switch, supplying electronic components, or changing NC p
Asai Jun
Kano Yoshinori
Takemura Ikuo
Yamaguchi Haruhiko
Morrison & Foerster / LLP
Sanyo Electric Co,. Ltd.
Tran Khoi H.
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