Correlation of Printed Circuit Board Properties to Pad-Crater Defects Under Monotonic Spherical Bend
Bibliographic record
Abstract
The restriction of lead in solder has caused a change in base materials used to make electronics—the result of which has been a new failure mode known as pad-crater. The susceptibility of six commercially available printed circuit board (PCB) laminates to pad-crater by spherical bend test was determined. The correlation of PCB laminate tensile properties, Vicker’s hardness (VH) of the resin, and weave dimensions showed an inverse relation between susceptibility to pad-crater and VH. Spherical bend testing of pure G10 laminate showed the orthotropic nature of laminates must be accounted for when modeling spherical bend. Comparison of bare PCB spherical bend test results showed the warp and weft direction have different strain responses for some materials. Comparison of strain energy of printed circuit board assemblies and bare PCB subjected to spherical bend showed the additional stiffness added by the ball grid array is almost identical for PCB laminates with different tensile properties.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".