Case 2659 ยท Public preview
A Loose Bimetal Spot Weld Can Destabilize Thermal-Switch Operation
Thermal switches failed during investigation or opened at an unintended low temperature even though external and X-ray examinations did not reveal a clear internal misalignment.
Electrical resistance measurementX-ray imagingControlled dissectionSEMFailed-to-stock comparison
What the evidence preview establishes
Failure correlated with plastic deformation and peripheral fracture of the spot weld attaching the bimetal element to its steel support. Failed units had mechanically loose welds, whereas stock controls had firm welds without significant deformation or fracture.
Why this case matters
A thermal switch can be electrically and geometrically simple yet fail through loss of mechanical constraint. Compare weld integrity and physical firmness between failed and stock parts before treating corrosion, coating, or visible alignment as the primary cause.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, 4 interpreted figures, alternative explanations, limitations, and practical application guidance.