Which ÖLFLEX® and UNITRONIC® cables are suitable for use in technical vacuum applications?
Vacuum technology is particularly prevalent in the coating industry, where it is used for a large number of products. Vacuums enable the application of very thin layers to the relevant product, while preventing oxidation and contamination. Today, products such as compact discs, eyeglass lenses, precision optical components, mobile telephones, tools, semiconductors and even flat screens are coated under vacuum conditions. In vacuum coating systems, it is often necessary to pass cables through the vacuum, e.g. to contact light sensors. In many cases, the evaporation produced in the negative vacuum pressure results in increased ambient temperatures, which further limits the potential cable selection. The size of the occurring negative pressure is also relevant.
Many insulation and outer sheath materials already emit substances, such as plasticisers, at normal atmospheric conditions and this process is both facilitated and accelerated by the negative pressure in a vacuum. As a result, cables can harden and embrittle prematurely, while the emitted substances can contaminate the entire vacuum. Due to their relatively high gas emission, plastics such as PVC, chloroprene rubber and silicone in particular are less suitable for vacuum applications.
Although we have limited experience and test data with regard to vacuum applications, we would recommend the use of fluoropolymer cables made of PTFE, such as the ÖLFLEX® HEAT 260, due to their wide temperature range and very low gas emission. Plastics such as PEEK (polyetheretherketone), PI (polyimide) and PA (polyamide) are also well suited to vacuum applications, but these materials are very stiff and quite expensive, making them unsuitable for use for standard cables.