Adaptive Solder Joint Inspection for Geometric Tolerances

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Solution Overview

Problem

Existing solder joint inspection systems in SMT production face challenges due to geometric component tolerances, leading to pseudo-defects and high scrap rates, as they cannot accurately distinguish between good and bad solder joints without manual re-checks.

Innovation Solution

The system adapts the inspection area dimensions and position based on real-time geometric component parameters, integrating automatic component checking data to optimize the evaluation algorithm, reducing slippage and pseudo-defects by dynamically adjusting the inspection criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fixed inspection areas are used for solder joint inspection, then the inspection process is simple and fast, but geometric component tolerances cause pseudo-defects and high scrap rates

Engineering Contradiction:
Improveinspection speedVSAvoidinspection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The inspection system dynamically adjusts the inspection area position and dimensions based on actual component geometric parameters. Instead of using fixed inspection areas, the system calculates and adapts the inspection window location according to measured component positions and dimensions, thereby accommodating geometric tolerances while maintaining inspection accuracy and reducing pseudo-defects.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the inspection parameters (position and dimensions of inspection areas) based on actual component measurements. By adjusting these parameters dynamically according to measured component geometry, the system adapts to manufacturing variations and eliminates pseudo-defects caused by fixed inspection parameters.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If manual re-checks are performed to verify pseudo-defects, then inspection accuracy improves, but production time and cost increase

Engineering Contradiction:
Improveinspection accuracyVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The inspection system performs self-correction by automatically adjusting inspection areas based on measured component parameters. The system eliminates the need for manual intervention by autonomously adapting to geometric variations, thereby maintaining high inspection accuracy while avoiding the time loss associated with manual re-checks.

Inventive Principle:
Principle #25Self-service

3Device complexity

If fixed inspection criteria are used, then the inspection process is simple, but it cannot accommodate component geometric variations

Engineering Contradiction:
Improveinspection process complexityVSAvoidaccommodation of geometric tolerances
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system transitions from static to dynamic inspection criteria by continuously adjusting inspection area parameters based on measured component geometry. This dynamic adaptation enables the system to accommodate geometric tolerances while maintaining a relatively simple overall process structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The inspection parameters are changed dynamically based on measured component parameters. The system calculates appropriate inspection area positions and dimensions according to actual component geometry, enabling adaptability to geometric variations without significantly increasing process complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3348125B1System and method for checking solder joints
Publication Date: 2020.07.22 ROBERT BOSCH GMBH
  • EP3348125B1 patent drawingFigure 1
  • EP3348125B1 patent drawingFigure 2
  • EP3348125B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a system (1) for checking solder joints, comprising a device (5) for automatic solder joint inspection which determines at least one quality feature of a solder joint to be checked in a predetermined inspection region of the solder surface, wherein the device (5) for automatic solder joint inspection scores the solder joint to be checked according to the determined quality feature, as a good solder joint (ASJIRG) or as a bad solder joint (ASJIRB), and a method for solder joint inspection. According to the invention, a device (4) for automatic component checking determines at least one geometric parameter of a component to be soldered, wherein, depending on the determined at least one geometric parameter of the component to be soldered, an evaluation and control unit (10) determines position and/or dimensions of the at least one corresponding inspection region and specifies same to the device (5) for automatic solder joint inspection in order to check the corresponding solder joint.