Page 17 - Lehrbuch Neigungsmessung deutsch 2018.indd

COMPENDIUM INCLINATION MEASUREMENT
WYLER AG, WINTERTHUR / SWITZERLAND

1.14 LENGTH OF MEASURING BASES

Inclinometers that are mainly used for adjustment and levelling jobs, but not for flatness or straightness
measurements, should be equipped with a measuring base (or complementary base) that is as long as
possible. The influence of local errors on the measured object (e.g. buckles) can be reduced when long
measuring bases are used. (Naturally, light measuring instruments should be used for light construction
work!)
For straightness measurements of guideways and for flatness measurements of surfaces, the following
criteria should be observed:
• Short measuring bases detect short waves (local error) and thus generate a dense information
content
• Short measuring bases require more time during the measurement process and thus create higher
costs
• Short measuring bases used on large work pieces end up in a large number of measurements
increasing the total measuring error
• Long measuring bases detect only long-wave errors
• Long measuring bases reduce the measuring time required, thus saving costs
• Long measuring bases require a smaller number of measurements, thus reducing the possibilities
for measuring errors. Therefore the measuring uncertainty in respect of the total dimension of a mea-
sured object is drastically reduced

MEDIUM INFORMATION DENSITY
Short waves of 50 to 200 mm in length.
These can be the result of unsuitable machining
methods in production, e.g. when too small lapping
tools are used for the lapping of a surface plate. Lo-
cal wear can also lead to errors of this type. This
category of errors is interesting for the flatness mea-
surement being discussed.

LOW INFORMATION DENSITY
Long waves over the whole surface. The general shape of a surface.
Reasons for this category of errors are:
• Copied geometrical errors originating from the
production machine
• Deformation due to clamping and support
• Distress of the material
• Thermal lamination within the workpiece

Page 17