Spot Welding Gun Electrode Control for Faster Collision-Free Travel

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Solution Overview

Problem

Current spot welding methods face inefficiencies in reducing welding cycle time due to inconsistent contact point determination, force fluctuations, and wear-related issues, leading to increased cycle duration and reduced production capacity.

Innovation Solution

An adaptive control method for the traveling electrode of a spot welding gun, utilizing a linear actuator, position sensor, and force sensor, where the electrode moves at maximum speed until reaching a compressive force, then slows down to a consistent point of contact, determined by a linear function representing the welding gun rigidity, to accurately set the starting point for low-speed movement, thereby reducing cycle time and preventing collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the traveling electrode moves at maximum speed during the free movement portion, then the welding cycle time is reduced, but the electrode may collide with the parts at high speed causing damage

Engineering Contradiction:

Improvewelding cycle timeVSAvoidelectrode and part damage from collision

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary determination of the contact point using force sensor data and linear function analysis before the electrode reaches it. This advance knowledge allows the control system to plan the speed reduction timing, enabling the electrode to travel at maximum speed for longer while still preventing high-speed collision through timely deceleration.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If the electrode slows down early to prevent collision, then damage risk is reduced, but the welding cycle time increases

Engineering Contradiction:

Improveelectrode and part damage from collisionVSAvoidwelding cycle time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system uses real-time feedback from the force sensor to monitor the actual contact point and compares it with the predicted contact point from the linear function. This feedback loop allows continuous optimization of the speed reduction timing, ensuring the electrode slows down at the precise moment to prevent collision while maximizing the high-speed travel portion of the cycle.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the contact point determination is inconsistent, then the starting point for low-speed movement varies, but this leads to increased cycle duration and reduced production capacity

Engineering Contradiction:

Improvecontact point determination consistencyVSAvoidproduction capacity

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The system replaces traditional mechanical or manual contact point determination methods with an automated computational approach using force sensor data and linear function analysis. This substitution provides consistent, repeatable contact point identification that eliminates variability and enables optimized cycling while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Loss of time

If the electrode moves at high speed close to the contact point, then cycle time is reduced, but the risk of collision and damage increases

Engineering Contradiction:

Improvewelding cycle timeVSAvoidcollision risk

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The system determines the contact point in advance using force sensor measurements and linear function prediction before the electrode arrives at that position. This preliminary determination allows the control system to calculate the optimal point for initiating speed reduction, enabling the electrode to maintain high speed as close to the contact point as safely possible while preventing collision.

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 consistently determines the contact point, reduces the duration of low-speed movement, increases production capacity, and minimizes the risk of electrode and part damage by accurately controlling the welding process, even with wear and varying part thicknesses.

Implementation Method 1

an electromechanical actuator (hereinafter—the EMA)

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

electric current is passed through the electrodes and the parts. The current causes local heating and melting of the metal

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a force sensor arranged for sensing a force acting on the traveling electrode

Methodology Applied

Scientific EffectMechanical force measurement: Force

Data Source

PatentUS20230241706A1Method for adaptive control of a welding gun traveling electrode

Publication Date: 2023.08.03 DIAKONT SRL

AI summary

A method for adaptive control of the traveling electrode of a spot welding gun includes causing the traveling electrode of the welding gun to move at a first speed when performing a welding (working) cycle and to switch to a second speed at a point, the coordinate of which is calculated based on the point of contact of the coordinate of the electrode obtained at the configuration cycle performed before the working cycle. The method allows for a reduction in welding cycle time.