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error; temperature deformation device system machine-device-
tool-detail; Inaccurate setup and setup; wear of a cutting tool;
deformation of the part as a result of redistribution of internal
stresses, etc. Analysis of the reasons for the appearance of a
deficiency and its elimination is a direct task of the technologist
of the shop. Studying the causes causing the errors of the
machined parts allows us to establish a connection between
these causes and the error values. Influencing in some way
causes that cause errors, you can reduce the last to the
minimum value.
Deviations in the size of parts are due to limits of
numerical values of variations in dimensions: equipment,
devices, instrument, measurements, etc. These deviations
(errors) are divided into systematic and random.
Systematic errors are a component of the measurement
error, which remains constant or naturally changes with
repeated measurements of the same magnitude. The occurrence
of systematic errors is due to relevant reasons. For example, the
inaccuracy of making an instrument leads to an error, which has
a systematic nature (constant for the entire batch of parts).
Random errors are errors, uncertain variables in
magnitude and sign, occurrence which can not be predicted
prematurely. These errors arise from the common manifestation
of a large number of causes. For example, oscillation of the
leak, heterogeneity of the material, etc. Random errors lead to
scattering of parts sizes in one batch. Their total error is defined
as the quadratic average.
In mass production, the estimation of the impact of a
combination of systematic and random factors on the accuracy
obtained is determined by the statistical method. At the heart of
the method is the determination of the overall error by finding
the size of the batch of the processed parts and analyzing the
results by methods of mathematical statistics. The resulting

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