GadCap Celebrates 20 Years of Laser Welded Probe Manufacture

April 2022 is the 20^th Anniversary of Laser welded high temperature CapaciSense probes for gas turbine blade health monitoring.

The challenge back in 2002 was to create robust sensors that connected to the in house manufactured triaxial mineral insulated cable.  The inner, central guard and outer sheath of the cable required electrical connection to the sensor.  At the same time, the three elements needed to be insulated electrically from each other using materials which could withstand over 1000°C.  Since 1996 this had been achieved using manual TIG welding, but a more reliable and repeatable method was required.

Laser beam welding was selected as the primary assembly technology as it was a proven technology which provided a reduced heat affected zone with enhanced resistance to vibration loads giving accurate and repeatable results.  The technique had already been used for low temperature applications involving mainly spot welds or resistance temperature devices with a maximum of two seam welds, but the challenge was to apply this to the high temperature CapaciSense probe application.

The first ten probes were successfully completed in April 2002.

Today, laser welding of sensors is still the method used and GadCap have produced over 300 separate designs.   Whilst the principle of CapaciSense sensors remains the same, much development has occurred over the years with sensors becoming smaller and more complex in design to suit client needs.   Verification testing has also evolved to include environmental, vibration, thermal and calibration testing.

Contact GadCap for all of your blade tip clearance and blade tip timing requirements.