Two suppliers were blamed. The real cause was a removed baffle.
A glass tempering line in Zhejiang replaced 17 heating elements in three months. Two suppliers were tried; both were blamed; the failures continued.
The failed elements showed brittle fracture rather than melting. Breaks clustered in the middle section of the furnace. The fracture faces were slightly brighter than the surrounding wire — a sign of local overheating.
Resistance and power configuration checked out.
Support spacing was 280 mm, within specification. Expansion allowance was present. No distortion.
Installation was not the cause.
The process team noticed that the baffle in the middle section of the furnace had been removed during maintenance in late 2024 and never reinstalled.
Without the baffle, hot-gas circulation in that zone degraded. The elements there could no longer shed heat as designed. Surface temperature rose by roughly 100 °C above design.
The baffle was reinstalled temporarily and the line ran for a month. Element failures: zero.
Not element quality. The elements were being asked to run 100 °C hotter than design, and life falls steeply with temperature. Elements rated for 12 months lasted three.
They inspected the elements in isolation. That is understandable — a supplier remote from the site cannot see a missing baffle. But a supplier who asks "has anything changed in the furnace recently?" would have shortened the investigation considerably.
Roughly 150,000 in lost production, 80,000 in unnecessary element purchases, and three months of investigation.
Has anything changed? What is the surface load? What is the atmosphere? What does the failed part look like? Those four questions resolve most cases — including the ones where the answer is not a new element.
