Kitagawa MR250RAE13, Instruction Manual

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39
NOTICE
17. Indexing Accuracy and Pitch Error
“
What is the linear length at the table circumference with
20 seconds cumulative indexing accuracy ?
”
“
What is the angle with a cumulative pitch error of
0.01mm ?
”
To answer these questions, use the following formula
representing the relationship between the angle and linear
length at the table circumference.
D
：
Diameter of Workpiece (mm)
α：
Angle (seconds)
L
：
Linear length at the table circumference (mm)
(1)
" 60 ' 60 360
･･････････ ･･････････ ･･････････ ･････････
× × °
=
×
α
π
D
L
(2)
10 125 . 4 60 60 360
5
････････ ･･････････ ･････････
D
L
D
L
× ×
=
×
× × ×
=
π
α
(3) 10 424 . 2
60 60 360
6 ･･･････ ･･････････ ･････････
D
D
L
× × × =
× ×
× ×
= −
α
π α
(Examples)
Assuming the diameter of the workpiece is 100mm, and by using formula (2), the
cumulative indexing accuracy of 20 seconds as linear length at table circumference will be
：
mm L 004848 . 0 10 100 20 424 . 2
6
= × × × =
−
Therefore, the length is approximately 0.0048mm.
And converting the cumulative pitch error of 0.01mm to an angle, use formula (3)
：
" 25 . 41
100
10 01 . 0 125 . 4
5
=
× ×
=
α
Therefore, the angle is approximately 41 seconds.
Thus, by using the formula (2) and (3), the indexing precision and pitch error can be
converted in terms of linear length and angle.