Things to know about gap measurement


Probing

The gapMaster works with a tactile measuring method, which has in the regular line
contact of the test object. The probe element can be specially designed for punctiform
contact, as is necessary for measuring the inside diameter. The sensor of the gapMaster
is placed inside the gap. The conversion of the measured value into electrical signals
takes place directly at the measuring point. The design of the sensor shaft as a thin,
elastic blade, which can also assume lengths of more than 500 mm, makes it possible
to measure even in places that are difficult to access. Due to a special sensor development
by MFP, even gaps with small depths of a few millimeters can be measured.

Resolution and accuracy

The gapMaster has a resolution of 12 bit. This means that with a measuring range of
5 mm, for example, readable values of approx. 2 µm are possible. To increase the
accuracy a linearization of the sensor characteristic curve is performed. Depending
on the sensor shape, accuracies of better than 10 µm can be achieved. The sensing
and guiding of the sensor has a significant influence on the measuring result.
In principle, the sensor is mounted floating in the gap so that the correct dimension is
always recorded.


Cut-off frequency

The cut-off frequency of the measured value recording is determined by the
spring-mass system for probes. The lower the mass the higher the cut-off frequency.
The sensor element of the gapMaster has a very small mass of less than one gram
and can therefore also be used for higher frequencies.