Process configuration also becomes a key variable when implementing a thermal spray coating solution, as manufacturers need to determine whether to build a new line or retrofit an existing line.
Implementation within a greenfield site provides obvious advantages in terms of flexibility and optimal integration, whereas an existing (brownfield) manufacturing operation requires the manufacturer to insert the spray coating system into the existing line. In this case, the setup recommended is one that integrates fine boring with surface preparation, coating, and then a rough hone bore finish.
Automakers should carefully balance their manufacturing goals, prioritising the relative importance of simplicity, engine performance and overall investments.
The SmartSprayComau system has been designed to support manufacturing priorities and seamlessly integrate within the existing processes. The reason why the thermal spray technology is surprisingly easy to implement, even within a high-volume production line, is because it essentially substitutes one process with another.
At the same time, the machining process of the PTWA-coated aluminium engine is identical up through the final bore steps. Here, instead of finishing boring the cylinder bores, the bores are roughened and sprayed with a thin layer, that are 0.1 to 0.15 millimetres thick (final thickness), of molten steel. Once sprayed, the process continues as before with the final finishing processes.
Benefits Of PTWA
Whether designing a new line or retrofitting an existing one, thermal spray coated cylinder bores is becoming an essential solution for advanced light alloy engine production.
Among the many advantages of PTWA, the plasma coated cylinders are more durable than non-coated cylinders, and the treatment can ensure a reduction up to 0.5 kg per cylinder according to the engine’s geometry.
In terms of thermodynamics and tribology, PTWA delivers NVH, knock and friction reductions, and performance enhancements including reduced heat loss, emissions and consumption. And because it can easily coat cylinder bores measuring from 70 millimetres in diameter and upwards, new engine models can be seamlessly inserted into the line with minimal modification of the PTWA production cell. At most, there may be minor adjustments related to the interfaces with the new block.
Continued from "Enhancing Engine Performance With Thermal Spray Coating" Part I
APMEN Sept 2016, Features
