HEW-KABEL PTFE and HEI-Tape®: Special Cables for Demanding Medical Applications

PTFE materials are well-known and have been used in medical cable technology for many years. HEW-KABEL has established a unique level of technical know-how in the design and processing of PTFE for cables over more than 40 years. Excellent electrical, thermal, chemical and physical properties ensure that PTFE can be used in medical applications even under extreme conditions.
Although PTFE can be processed in a paste extruder, this, discontinuous, process has some distinct disadvantages in short lengths and mechanical properties like limited stress crack resistance and limited pressure resistance. These disadvantages can be avoided by another manufacturing method, taping, which in turn introduces the reduction in abrasion due to the overlap of the tapes. The uniqueness of HEW-KABEL’s taping technology lies in the ability to produce taped cables with a very smooth surface, making it virtually impossible to see the difference between extruded and taped product, whilst having all the benefits of tape.

Using its extensive taping and PTFE knowledge, HEW-KABEL has developed a new process to manufacture expanded PTFE tapes. Through careful selection of insulation and sheath material associated with expanded PTFE, the compressive stress of the cable is reduced so that the material fatigue of the cable is finally minimized and the service life increased.
Because of its excellent sliding properties, these tapes can be implemented in strands and jackets. Expanded PTFE tapes can also be used for the manufacture of Robot cables which require high flexibility and high flexlife. Plane robot cables with integrated data lines, coaxial cables, control cables and supply cables with expanded PTFE as gliding material are produced by HEW-KABEL and have been on the market for some time.
Another newly developed process makes it now possible to manufacture expanded PTFE tapes with a very steady distribution of the embedded pores. The new brand HEI-tape® is implemented in the field of high frequency technology because of its excellent dielectric properties. The dielectric constant is 1,2 compared to 2,1 for massive PTFE. The dielectric loss of products made with HEI-tape is significantly lower than with solid PTFE.
The steady structure of HEI-tape tapes allows that data cables manufactured with this material can be implemented for data transmission up to the GHz area. Furthermore, these cables have a very small outer diameter and lower weight. Through the porous structure, the signals are carried forward almost at light speed. Loss and distortion of the signals are minimized, too.
Compared to coaxial cables made of other foamed fluorpolymers, coaxial cables with a dielectric of HEI-tape have a higher data rate transmission (High Speed Cables) because of better distributed porosity. RG 400 HEI-tape coaxial cables have a reduced diameter of up to 30%, a lower weight of up to 60% and a smaller attenuation of up to 10% compared to a coaxial cable made of massive PTFE.

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