Coating plant

Coating thickness is controlled through a stable process. This requires a stable evaporation process, and that is exactly what the camera monitors. The ceramic layer on turbine blades has to be applied with a targeted thickness distribution, and even small process deviations change its quality. At ALD, the Advanced Observation System detects fill level, surface movement and overflow in the melt pool live. The operator can intervene before the batch is damaged. Individual sensor readings are usually not enough.

The ceramic thermal barrier coating is created when an electron beam evaporates ceramic material in a vacuum chamber. The turbine blades are moved in translation and rotation within the vapour cloud so that a homogeneous layer only micrometres thick forms. Its main purpose is thermal insulation, because temperatures inside the turbine come close to the load limit of the materials. As a defective batch is expensive, ALD monitors the process with cameras and image recognition.

In an electron beam evaporation system, image processing makes the process inside the closed vacuum chamber continuously visible and detects anomalies automatically. ALD's EB Vision Monitoring only reacts to changes in light intensity and only then sends a signal to the software. This cuts the data volume drastically, so neither powerful processors nor high-bandwidth networks are needed. The resulting values are stored in a time series database and allow long-term analysis of the process.

Coating defects are avoided by detecting deviations while the batch is still in the plant. Previously, an operator had to spot deviations manually. A faulty coating can be removed, but this is more complex and expensive than the coating itself. At ALD, the Advanced Observation System shows anomalies directly in the live video so that the operator can intervene immediately. Process videos are stored with time stamp and batch number.