Board Work Machine Reference Mark Recognition Tolerance

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Solution Overview

Problem

Board work machines face challenges in accurately recognizing reference marks on boards with both overall and local area reference marks, requiring improved accuracy and practicality in positioning for precise component mounting and inspection.

Innovation Solution

A board work machine with a board fixing device, imaging device, and control device that sets different tolerances for recognizing overall and local area reference marks, allowing for precise positioning and reducing misrecognition by adjusting the tolerance based on the separation distance of the reference marks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single tolerance value is used for recognizing all reference marks on a board, then the recognition process is simple, but the accuracy of board work deteriorates when both overall and local area reference marks are present

Engineering Contradiction:
Improvereference mark recognition accuracyVSAvoidtolerance setting complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by setting different tolerance values for different types of reference marks. Overall reference marks use a first tolerance value, while local area reference marks use a second tolerance value. This allows the recognition system to adapt to the specific requirements of each reference mark type, improving recognition accuracy without requiring a completely complex multi-parameter system.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If a small tolerance is set for recognizing reference marks, then the precision of board work is improved, but the risk of misrecognition increases when reference marks have separation distance variations

Engineering Contradiction:
Improveboard work precisionVSAvoidreference mark recognition reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements local quality by assigning different tolerance levels to different reference mark categories. Overall reference marks, which may have larger separation distances and greater positional variations, are given a larger first tolerance. Local area reference marks, which require higher precision, are given a smaller second tolerance. This differentiated approach ensures both precision and reliability for each reference mark type.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple different tolerances are set for different reference marks, then the accuracy of board work is improved, but the complexity of the control system increases

Engineering Contradiction:
Improvereference mark recognition precisionVSAvoidtolerance configuration ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a straightforward classification system with two tolerance types. The control device is configured to automatically apply the first tolerance to overall reference marks and the second tolerance to local area reference marks. This simple binary classification makes the system easy to operate while still achieving high precision through differentiated tolerance values.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3236728B1Substrate work machine
Publication Date: 2020.04.08 FUJI CORP
  • EP3236728B1 patent drawingFigure 1
  • EP3236728B1 patent drawingFigure 2(a)~2(b)
  • EP3236728B1 patent drawingFigure 3

AI summary

In a board work machine that performs board work with reference to a reference mark provided on a board, in a case of performing board work with respect to a board provided with overall reference mark FM1 and local area reference mark FM2 that acts as a reference for a local area A as reference marks, when recognizing the reference marks by imaging, checking is performed as to whether a recognized reference mark is recognized correctly. For this checking, when checking whether the position deviation amount ΔX and ΔY from a normal position and the relative position deviation amount ΔL of an imaging target identified as a reference mark is within the range of a set tolerance, set tolerances TΔX2, TΔY2, and TΔL2 for a local area reference mark are smaller than set tolerances TΔX1, TΔY1, and TΔL1 for an overall reference mark. By setting set tolerances as such, check processing can be performed reliably.