53
NOTICE
22. Reference Data
22-1. Conversion of arc length and angle
“
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
･･････････
･･････････
･･････････
･････････
D
L
(2)
10
125
.
4
60
60
360
5
････････
･･････････
･････････
D
L
D
L
(3)
10
424
.
2
60
60
360
6
･･･････
･･････････
･････････
D
D
L
(Examples)
Assuming the diameter of the workpiece is 100mm, and by using formula (3), 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 (2)
：
"
25
.
41
100
10
01
.
0
125
.
4
5
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.
