Photochemical etching (PCE) proves to be the most efficient and cost-effective manufacturing technology available for the production of plate heat exchangers. An important application area for such plates is fuel cells, where materials such as stainless steel, aluminum, nickel, titanium, copper, and various special alloys are used. Metallic plates offer numerous advantages in fuel cells: they are extremely robust while ensuring excellent conductivity for efficient cooling.
For plate applications, PCE represents an attractive alternative to stamping and machining processes, as the method is characterized by the preservation of material properties, burr-free and stress-free components with clean contours, and the absence of heat-affected zones. Furthermore, the liquid etching medium creates optimal structures for the cooling media used in the plates. These structures have no sharp edges or corners that could be susceptible to corrosion.
Often, both sides of plate heat exchangers feature extremely complex structures that are partially not feasible with stamping or machining processes but can be easily produced with PCE. In addition, PCE allows for the simultaneous processing of both plate sides, resulting in significant cost savings. The process is applicable to various metals, including stainless steel, Inconel 617, aluminum, and titanium.
Another important factor in choosing the manufacturing process is material thickness. Conventional methods often reach their limits when processing thin metals: stamping and punching are unsuitable in many cases, while laser and waterjet cutting can lead to undesirable heat effects or material fraying.
PCE, however, is suitable for various material thicknesses and is particularly distinguished by its ability to process even very thin metal sheets – as used in plate heat exchangers – without impairing flatness, which is crucial for component integrity. For thin sheets, PCE allows for shorter stack heights, and no direction-dependent surface structures are created in the channels. Profiling and channel structures can be created simultaneously. It should be noted that with stamping, the metal is deformed to form channels, whereas PCE precisely removes the required amount of material to create the desired channels.
The PCE process ensures reproducible tolerances for all critical plate dimensions, including the depth of gas guides and the geometry of manifolds, and enables the production of components according to stringent pressure drop requirements.
