PCB Z-Position Interpolation for Test Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in testing printed circuit boards is accurately determining the Z position of contact points without lengthy metrological measurements, due to board distortions and sagging, which can cause test tips to miss or incorrectly strike components.
Innovation Solution
The method involves using reference points with known positions to interpolate the actual Z position of the printed circuit board through mathematical interpolation, such as natural neighbor interpolation, allowing for faster calculation of component heights and contact point positions without individual metrological capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual metrological measurements are performed for each contact point to determine its Z position, then measurement precision is improved, but testing time increases significantly
Solution Approach 1:
The patent creates a digital model (copy) of the printed circuit board's actual Z position by measuring reference points and using interpolation to calculate contact point positions. This virtual model replaces the need for direct physical measurement of each contact point, significantly reducing measurement time while maintaining accuracy
Solution Approach 2:
The patent performs preliminary measurements of reference points before actual contact point testing. The interpolated Z position data is prepared in advance, allowing the test tips to be positioned accurately without performing time-consuming individual measurements at each contact point during the actual testing phase
2Speed
If test tips are positioned based on nominal Z positions without accounting for board distortion, then positioning speed is improved, but measurement precision deteriorates due to board sagging and distortion
Solution Approach 1:
The patent implements a feedback mechanism where the actual Z positions of reference points are measured and used to update the interpolated model of the board's deformation. This feedback loop allows the system to compensate for board distortion and sagging, ensuring accurate contact point positioning while maintaining efficient test tip movement
Solution Approach 2:
The patent changes the parameter basis for test tip positioning from fixed nominal Z positions to dynamically calculated actual Z positions derived from reference point measurements and interpolation. This parameter transformation allows the system to adapt to board deformation while maintaining positioning speed through efficient mathematical calculations
Data Source
AI summary
A method for testing printed circuit boards (20) in a test apparatus having a carrying apparatus for the printed circuit board (20) and having test modules for measuring physical variables of components (EB) and contact points (29) on the printed circuit board (20), in whichthe width of the printed circuit board (20) defines an X direction, its length defines a Y direction and its thickness defines a Z direction inside the test apparatus,reference points, the X, Y and Z positions of which relative to the carrying apparatus are known, are present on the printed circuit board (20) or outside the latter,the X and Y positions of the components (EB) and contact points (29) relative to the reference points are known,the measurement of the physical variables depends on an actual Z position of the printed circuit board at the X and Y positions of the component (EB) or contact point (29) to be measured, andthe actual Z position of the printed circuit board at the X and Y positions of the component (EB) or contact point (29) to be measured is determined by means of an interpolation method starting from the X, Y and Z positions of selected reference points.