Wire Clamp Calibration via Piezoelectric Vibration Current

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Solution Overview

Problem

Conventional wire clamp apparatuses face challenges in accurately controlling the opening amount of arm portions due to variations in temperature, time, and torque, leading to instability in wire bonding operations.

Innovation Solution

A calibration method involving a predetermined frequency to drive the piezoelectric element, detecting collisions using output current, calculating reference voltages, and calibrating the driving voltage to adjust the opening amount accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a piezoelectric element is used to control the opening/closing of arm portions, then the wire can be constrained or released, but the opening amount varies due to temperature changes and torque differences

Engineering Contradiction:

Improvewire constraint and release operationVSAvoidopening amount stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies vibration at a predetermined frequency to the piezoelectric element during calibration. By detecting collision between arm portions through vibration analysis of the output current, the system can accurately determine the closed state position. This vibration-based detection method enables precise calibration of the opening amount despite temperature variations and torque differences, thereby improving reliability while maintaining ease of operation.

Inventive Principle:

Principle #18Mechanical vibration

2Productivity

If the arm portions are driven by voltage to open and close, then wire bonding can be performed, but accurate control of opening amount is difficult

Engineering Contradiction:

Improvewire bonding operationVSAvoidopening amount control accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the output current from the piezoelectric element is analyzed during vibration. By detecting collision between arm portions through this feedback signal, the system can accurately determine when the arm portions reach the closed state. This feedback enables precise calibration of the opening amount, ensuring accurate control while maintaining high productivity in wire bonding operations.

Inventive Principle:

Principle #23Feedback

3Duration of action of moving object

If conventional driving voltage control is used, then the wire clamp apparatus can operate, but the opening amount varies over time

Engineering Contradiction:

Improvewire clamp operation durationVSAvoidopening amount consistency

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent performs preliminary calibration action by vibrating the piezoelectric element at a predetermined frequency before normal operation. During this calibration phase, the system detects collision between arm portions and calculates the reference voltage for the closed state. This preliminary calibration establishes accurate baseline parameters that compensate for temperature changes and torque variations, ensuring consistent opening amount throughout the duration of wire clamp operations.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enhances the accuracy and stability of the opening/closing operation of the wire clamp apparatus, ensuring precise and reliable wire bonding.

Implementation Method 1

a driving portion provided with a piezoelectric element that causes the pair of arm portions to open and close

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

detecting whether the front end portions of the pair of arm portions have collided based on an output current outputted from the driving piezoelectric element when the pair of arm portions are vibrating

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS11004822B2Wire clamp apparatus calibration method and wire bonding apparatus

Publication Date: 2021.05.11 YAMAHA ROBOTICS CO LTD

AI summary

This wire clamp apparatus calibration method comprises: a step for driving a driving piezoelectric element by applying a predetermined frequency that causes a pair of arm portions to vibrate in an opening/closing direction; a step for detecting whether or not end portions of the pair of arm portions collide with each other on the basis of an output current outputted from the driving piezoelectric element when the pair of arm portions are vibrating in the opening/closing direction; a step for calculating, on the basis of the detection result, reference voltages in a state where the pair of arm portions are closed; and a step for performing calibration of a drive voltage to be applied to the driving piezoelectric element on the basis of the reference voltages. Accordingly, accuracy improvement and stabilization in an opening/closing operation of the wire clamp apparatus can be achieved.