1. Distinguish thermal gradients from a generic heat label

Thermal shock describes a mechanical consequence of a changing thermal condition. The AVX explanation connects it to differences in expansion and heat flow within the component as temperature changes. An MLCC combines ceramic dielectric, internal metal electrodes and external terminations. Those materials and their interfaces are part of the stress account, so a general label such as heated does not identify the relevant physical relationship.

The historical paper explains that compatible materials can still differ in how they expand and conduct heat. When the thermal change is excessive for the structure, internal stress concentrates at constrained regions. This is different from describing only the highest temperature reached. The rate and distribution of thermal change affect how the materials interact, rather than being supplied by the mere fact that an assembly experienced a soldering process.

The source’s mechanism therefore links thermal gradients, differing material response and local mechanical constraint. It should not be converted into a conclusion that a particular process caused a particular crack. Nor does a recorded heating event establish an internal fracture. The explanation provides no numerical rate, material coefficient or process recommendation here; it identifies why thermal shock is a mechanical relationship within the layered structure rather than a generic temperature-history category.

2. Locate concentrated placement forces as another mechanism

Placement loading introduces another source of stress. AVX describes concentrated forces from centering jaws and the resulting force or shear gradients in the capacitor body. These act through mechanical compression rather than through the differing expansion of materials during thermal change. Both can stress the structure, but the source of the stress and the path by which it enters the component are different.

The paper relates body deformation under compression to a possible rupture of ceramic between internal electrodes. An internal defect need not have the same outward expression as an obvious surface crack. This distinction concerns where stress is relieved inside a layered body, not a rule assigning a crack pattern to one cause. The electrode and dielectric relationship matters because the mechanically affected region can also be part of the electrical separation.

Keeping concentrated placement forces distinct from thermal shock prevents an assembly-history label from doing too much explanatory work. A component can have a known process history while the actual origin of damage remains unestablished. The historical prose supports the possibility of internal damage, but supplies no present diagnosis, defect incidence or identification of a placement machine. It also provides no jaw setting, force limit or handling recipe to apply to unknown material.

3. Follow board flex through the constrained termination

After soldering, a board can transmit mechanical stress into a mounted capacitor through its constrained terminations. AVX’s account relates board deformation and component orientation to the stress gradient reaching the ceramic. The termination and solder fillet restrict local movement, while the board’s movement loads that connection. This is a transfer of mechanical influence through the assembly, rather than the direct centering-jaw compression described above.

The resulting tension also differs from thermal mismatch, even though more than one mechanism can involve the same material interface. Board flex asks how surrounding assembly movement reaches the component. Thermal shock asks how differing material response during temperature change creates stress. Retaining those different causal paths is more informative than treating every fracture as proof of a single generic problem called poor handling or soldering damage.

A soft-termination description belongs to a separate construction question. The historical Flexiterm paper discusses stress relief, but that feature does not remove the need to identify actual mechanical circumstances. No documented construction establishes that previously mounted material escaped damage. This account uses the board-to-component relationship qualitatively, without a bend fixture, component orientation prescription, layout margin, depanelisation instruction or diagnosis of cracks in offered units. The mechanism and the present condition remain separate subjects.

4. Separate a latent dielectric path from immediate capacitance

A fracture can also have an electrical consequence that is not immediately represented by a capacitance observation. The Flexiterm paper warns that fractures may not initially be obvious through capacitance and Q testing. That does not make the fracture harmless; it means that the physical defect and the particular observation describe different parts of the component’s condition at that time.

The paper then describes moisture entering a crack and creating a low-resistance path between adjacent electrodes. This supplies a physical route from a mechanical discontinuity to a later conductive path. Moisture entry and inter-electrode conduction are distinct from the original force that created the fracture. The account therefore separates the origin of damage from the way its electrical effect may become apparent under another environmental condition.

The distinction does not make every leakage observation evidence of a crack. Leakage can have other mechanisms, and an initial normal capacitance result does not establish future behavior. The historical explanation provides no delay, probability, remaining life or test prescription. It explains why a latent dielectric path and an immediate capacitance observation are different subjects, without certifying the condition of a lot or promising that an initial pass excludes internal mechanical damage.

Sources and further reading

Historical AVX Cracks and Flexiterm qualitative prose only; issue dates were not established. Figures, crack-shape identification, incidence, material values, thermal limits, process instructions, test recipes, delay estimates, repair and promised damage immunity are excluded. No present offered-part diagnosis is made.