Robot Spot Welding Time Comparison for Missing Spot Detection
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Solution Overview
Problem
Conventional spot welding systems struggle to promptly and accurately detect abnormalities such as 'spot missing' during the welding process, leading to inefficiencies in identifying and addressing issues, which can affect product quality and manufacturing yield.
Innovation Solution
A spot welding system that includes a robot-side and welder-side control unit, with a storage unit for required welding times, a welding time measurement unit, and a comparative determination unit to compare actual and required welding times, enabling precise detection of abnormalities and facilitating quick recovery and re-welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional spot welding systems simply count welding spots to judge appropriateness, then the judgment process is simple, but it cannot detect abnormalities such as spot missing and cannot identify the specific location of abnormalities
Solution Approach 1:
The system implements feedback by measuring actual welding time and comparing it with required welding time to detect abnormalities. The control unit receives welding completion commands and measures the time elapsed from welding start command output to completion command receipt, then compares this actual time with the required time stored in advance. When a discrepancy is detected, the system identifies an abnormality and can specify its location, enabling reliable detection without increasing system complexity.
2Ease of operation
If conventional systems use welding spot number counting to determine proper welding, then the judgment method is straightforward, but it cannot distinguish between properly welded spots and improperly welded spots
Solution Approach 1:
The system changes the detection parameter from welding spot number counting to welding time measurement. By measuring the actual welding time and comparing it with the required welding time, the system can precisely determine whether each spot was properly welded. This parameter change maintains ease of operation while significantly improving measurement precision, as welding time is a direct indicator of welding quality.
3Device complexity
If conventional spot welding systems do not monitor welding time, then the system operation is simple, but abnormalities cannot be detected promptly affecting product quality
Solution Approach 1:
The system replaces complex mechanical monitoring mechanisms with an electronic time measurement and comparison system. The control unit automatically measures welding time using electronic timers and compares it with stored required times, providing prompt abnormality detection without adding mechanical complexity. This substitution enables reliable quality control that improves manufacturing yield while keeping the system operationally simple.
4Ease of operation
If conventional systems rely on external observation of spatter to detect abnormalities, then the detection method is simple, but it is ineffective because servomotor-driven welders produce little spatter
Solution Approach 1:
The system introduces welding time as an intermediary parameter to detect abnormalities. Instead of directly observing physical signs like spatter, the system uses welding time measurement as an intermediary indicator that reliably reflects welding quality. This intermediary approach maintains ease of operation while significantly improving reliability, as time measurement is objective and not affected by the low spatter characteristics of servomotor-driven welders.
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 system allows for reliable and accurate detection of abnormalities during spot welding, preventing quality issues and improving manufacturing yield by enabling early recognition and correction of welding errors.
Implementation Method 1
energizing with a large electrical current while pressing the welded part with copper alloy electrodes of round rod shape, thereby heating the metal material of contacting parts by the electrical resistance to locally fuse together
Data Source
AI summary
To provide a spot welding system of high reliability which, when an abnormality such as a spot missing in spot welding occurs, is capable of more precisely and accurately detecting this immediately. Provided are a robot-side system having a robot and a robot-side control unit which controls driving of the robot; and a welder-side system having a welding gun mounted to the robot, and a welder-side control unit, in which the robot-side system includes: a storage unit which stores in advance a required welding time needed in a spot welding operation of one location or a plurality of spot welding operations; a welding time measurement unit which measures an actual time from when a welding start command is outputted until receiving a welding completion command; and a comparative determination unit which determines quality by comparing the required welding time stored in the storage unit and the actual welding time measured by the welding time measurement unit.