Micro Resistance Welding Control for Consistent Welds

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Solution Overview

Problem

Current micro resistance welding technologies face challenges in achieving long-term stable weld performance and consistency due to small changes in component size, positioning, surface finish, electrode wear, and mechanical tolerance, leading to batch manufacturing defects and production downtime, especially in safety-critical sectors like medical, aerospace, and automotive.

Innovation Solution

A micro resistance welding apparatus with real-time feedback control that modifies parameters to optimize electrode life and produce consistent welds by switching between current, voltage, and power control modes during the welding process, using a digitally controlled servo closed loop system to define a weld profile with multiple segments and adjust force control signals based on displacement and electrical feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If real-time feedback control with multiple control modes is implemented, then weld consistency and electrode life are improved, but device complexity increases

Engineering Contradiction:
Improveweld consistencyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically switches between voltage control mode, power control mode, and current control mode based on real-time welding conditions. The controller monitors welding parameters and automatically transitions between control modes to maintain optimal welding performance throughout the process, resolving the contradiction by making the control system adaptive rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements real-time feedback control by continuously monitoring welding parameters (voltage, current, power) and using this information to adjust control signals. The feedback loop enables the system to detect deviations from target welding conditions and automatically correct them, ensuring weld consistency despite variations in component parameters.

Inventive Principle:
Principle #23Feedback

2Productivity

If real-time feedback control is implemented, then production yield is improved, but device complexity increases

Engineering Contradiction:
Improveproduction yieldVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Real-time feedback control continuously monitors welding parameters and automatically adjusts control signals to maintain optimal welding conditions. This prevents defective welds and reduces rework, thereby improving production yield despite the increased complexity of the control system.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes control parameters (switching between voltage, power, and current control modes) based on real-time welding conditions. This adaptability allows the system to maintain high welding quality across varying production conditions, improving overall production yield.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If multi-segment weld profile with mode switching is used, then electrode life is extended, but device complexity increases

Engineering Contradiction:
Improveelectrode lifeVSAvoidcontrol system complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The control system dynamically switches between different control modes (voltage, power, current) during the welding process according to a multi-segment profile. This dynamic adaptation optimizes the welding parameters at different stages, reducing electrode wear and extending electrode life while managing system complexity through structured control logic.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The weld profile is divided into multiple segments, each with a specific control mode (voltage control, power control, or current control). This segmentation allows optimized control at different stages of the welding process, extending electrode life by preventing excessive heat input and wear during critical phases.

Inventive Principle:
Principle #1Segmentation

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 approach enhances process control and production yields by allowing real-time analysis and correction of welding parameters, reducing wear, and extending electrode life, resulting in more consistent and reliable welds.

Implementation Method 1

passing high current and low voltage through a work piece to heat up the joint interfaces to form a weld

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3600751B1Micro welding apparatus and method
Publication Date: 2022.03.02 AMADA WELD TECH UK LTD
  • EP3600751B1 patent drawingFigure 1a~1b
  • EP3600751B1 patent drawingFigure 2
  • EP3600751B1 patent drawingFigure 3

AI summary

The present invention relates micro resistance welding apparatus and to a method of welding. In particular, the present invention relates to small scale or micro welding apparatus and to a method of micro resistance welding using a controlled sequence of current, voltage and/or power signal profile for an electric arc. The invention provides a welding apparatus comprising: a controller supplying a controlled drive current to a weld head circuit in which the controller supplies said controlled drive current in dependence upon electrical feedback from the weld head circuit and in which the controlled drive current is defined by a sequence of segments and for each segment the welding apparatus operates in a mode defined by setting one of a predetermined current target, a predetermined voltage target or a predetermined power target; and at least two of the segments are operated in a different mode from one another. The invention also provide a method of operating such an apparatus.