US 6,293,006 B1Granted

Electronic component mounting method

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsTakeshi Takeda, Osamu Nakao, Akira Shiomi

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Abstract

A method of controlling a mounting unit having a shaft operated under servo control using a current driven actuator, comprises the steps of detecting interrruption of the servo control, and switching from a positioning control mode to a constant current control mode for supplying an constant amount of current to the shaft actuator to suspend the shaft. In an embodiment the method further includes engaging a gripping device, for holding the shaft, so as to keep the shaft from free-falling when interruption of the servo control is detected, and maintaining the constant current control mode at least until the gripping device grips the shaft. Still further, the current control mode optionally includes the steps of maintaining the supply of the constant amount of current for a predetermined period of time, and disengaging power supplied to the actuator after the predetermined period of time has elapsed.

Claims12

Dependent claims

An electronic component mounting method implemented in an electronic component mounting apparatus the mounting apparatus providing:

a nozzle for picking up and mounting an electronic component;
a voice coil motor having a shaft for moving said nozzle upwards and downwards;
a gripping device for gripping said nozzle to prevent said nozzle from free-falling by holding said shaft;
a control unit for controlling said nozzle and said gripping device;
a voice coil motor control unit for effecting position control mode for effecting positioning control and torque control of said voice coil motor by varying an amount of electric current supplied to said voice coil motor;
a system control unit for instructing said voice coil motor control unit;
and
a position detector for detecting a position of said voice coil motor in upward and downward directions and sending a signal indicating said position to said voice coil motor control unit to effect servo control;
said electronic component mounting method comprising the steps of:
providing said voice coil motor control unit with constant current control mode for supplying a constant amount of electric current for a constant period of time to said voice coil motor, said constant amount of electric current being set in said voice coil motor control unit so as to effect holding of said shaft;
and
switching from said position control mode to said constant current control mode when said positioning control of said voice coil motor is impeded;
and
engaging said gripping device, during said constant current control mode, so as to hold said shaft and avoid free-fall of said nozzle.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/332,675Filed 14 Jun 1999
Priority: JP 10-16668315 Jun 1998
Granted: 25 Sep 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H05K 13/0413
Pick-and-place heads or apparatus, e.g. with jaws: with orientation of the component while holding it; Drive mechanisms for gripping tools, e.g.…
Y10S 29/044
Metal working: vacuum
Y10T 29/4913
On flat or curved insulated base, e.g., printed circuit, etc.: assembling to base an electrical component, e.g., capacitor, etc.
Y10T 29/5303
With randomly actuated stopping or disabling means: responsive to condition of work or product

Family

No related US applications are recorded in the indexed filing history.

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