Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-10-25
2004-07-06
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S712000, C029S721000, C029S740000, C029S833000, C228S009000, C228S105000, C700S117000
Reexamination Certificate
active
06757966
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a system and method for mounting components, such as electronic components, on a board.
BACKGROUND OF THE INVENTION
Increasingly accurate positioning for mounting components onto electrodes on a board is required as electronic components such as semiconductors become smaller and mounting density becomes higher. Numerous micro components measuring about 0.6 mm×0.3 mm are mounted at a narrow pitch of about 0.1 mm in small apparatuses such as mobile phones which are becoming increasingly popular consumer items. Mounting of such small components requires extremely high mounting position accuracy.
When mounting the above-mentioned micro components, it is necessary to pay particular attention to the mounting quality control. More specifically, the quality of mounted boards needs to be assured with respect to their use over a range of conditions without causing any defects. Accordingly, an inspection is carried out on boards after mounting for assuring functions, and if the board is judged defective, it is repaired. In most cases, defective mounted boards are repaired manually such as by removal of defective components and the mounting of new, non-defective components.
In case of boards on which the aforementioned micro components are mounted at high density, the above repair operation is extremely difficult if the defect is determined after all the components have been mounted. Most boards which are judged defective in the inspection after mounting are thus disposed of, resulting in wastage of expensive electronic components mounted at high density.
In order to prevent such wastefulness, the next operation is implemented in order to minimize the occurrence of defects in the conventional mounting operation. The operation of the mounting line is periodically stopped to allow the checking and adjustment of each device in a mounting line using a test board; and calibration is implemented to update control parameters, such as positioning correction values in accordance with the latest conditions of the machine. Since these operations require the machine to be halted, the operation rate drops. Operators also need to spend considerable time and effort carrying out complicated adjustments. Accordingly, more accurate and efficient quality control during the mounting process is required to eliminate wasted time and materials.
These defects also occur due to secular changes in the fine-tuning of individual mechanical part of the component mounting devices. Defects may also occur when individual components in each mechanical part suffer wear and cause faulty operation. In general, by updating control parameters set in each device in accordance with machine conditions, it is possible to offset secular changes in the fine-tuning and maintain the mounting accuracy. However, defects caused by the wearing out of mechanical parts often require that components be replaced, and thus maintenance time is needed for replacing components.
Conventionally, there are no clear indexes for identifying the degree of wear of mechanical parts, and thus skilled operators are needed to identify and pinpoint abnormalities based on the operating conditions of each device, forecast the type and degree of degradation of mechanical parts, and announce the need for maintenance. Accordingly, if abnormal operation occurs suddenly, without being predicted, numerous defectives may be produced before the abnormality is noticed, causing large-scale losses and requiring immediate maintenance.
SUMMARY OF THE INVENTION
The present invention solves the above disadvantages, and aims to offer a component mounting system and mounting method which enables the more accurate and efficient control of quality during the mounting process; makes it possible constantly to monitor the conditions prevailing in each device constituting the component mounting system, and eliminates wastage due to defects by predicting faulty operation.
The component mounting system of the present invention is configured by connecting two or more devices, and manufactures mounted boards by placing and soldering components on the board. This system comprises the following devices:
(a) a printer for printing solder onto electrodes formed on a board:
(b) a first inspection unit for detecting the positions of printed solder and outputting solder position detection results;
(c) a component mounting unit for picking up components from a component feeder carriage with a mounting head, and placing these components on the board;
(d) a second inspection unit for detecting the positions of mounted components, and outputting the component position detection results;
(e) a soldering unit for soldering components onto the board by heating and melting solder; and
(f) a main controller for at least updating i) control parameters for controlling the operation of the printer; or ii) control parameters for controlling the operation of the component mounting unit based on at least solder position detection results or component position detection results.
The above configuration enables the component mounting system of the present invention to control quality more accurately and efficiently during the mounting process.
The method for mounting components of the present invention uses a component mounting system configured by connecting two or more devices, and manufactures mounted boards by placing and soldering components onto the board. This method includes the next steps:
(a) a printing step for printing solder on electrodes formed on the board using the printer;
(b) a solder position detection step for detecting the positions of printed solder and outputting solder position detection results using the first inspection unit;
(c) a placement step for picking up components from a component feeder carriage and placing them on the board using the mounting head of the component mounting unit;
(d) a component position detection step for detecting the positions of mounted components and outputting component position detection results using the second inspection unit; and
(e) a soldering step for soldering components onto the board by heating and melting solder using the soldering unit.
While executing each of the above steps, at least the control parameters for controlling the operation of the printer or control parameters for controlling the operation of the component mounting unit are updated based on at least solder position detection results or component position detection results.
This method makes it possible to update control parameters for controlling the printer and/or component mounting unit inline based on solder position detection results and/or component position detection results when executing each step in the component mounting process: printing, solder position detection, placement, component position detection, and soldering. Accordingly, the quality is more accurately and efficiently controlled during the mounting process.
REFERENCES:
patent: 5003692 (1991-04-01), Izumi et al.
patent: 5564183 (1996-10-01), Satou et al.
patent: 5822449 (1998-10-01), Kobayashi et al.
Fujioka Masat
Inoue Masafumi
Tsukamoto Mitsuhaya
Matsushita Electric - Industrial Co., Ltd.
Nguyen Donghai D.
RatnerPrestia
Vo Peter
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