Thickness measurement

Measurement method

A basic distinction is made between a contacting and non-contacting thickness measurement. The choice of method to be used depends on different criteria:

  • material composition (homogeneous or inhomogeneous)
  • material structure (solid, ductile or e.g. sticky)
  • material thickness to be measured
  • required accuracy
  • measuring spot size
  • measuring speed

Tactile measurement systems operate mainly with measuring rollers or rails which are pressed onto the material at different forces and the thickness is then deter­mined by the amount of their deflection.

Non-contact systems usually use laser, ultrasound, capacitive, inductive or air-cushion sensors as well as radiometric sources of radiation as measuring transdu­cers. Each of these measuring methods has specific advantages and disadvantages depending on the material to be measured which favour or restrict its application or make it impossible.