PMI's precision ground Ballscrews are controlled in accordance with JIS B 1192.
The permissible values and each part of defi nitions are shown below.

Technical Terms Concerning the Lead

Terms


T+E
 
 
　Cumulative representative lead.
　A straight line representing the tendency of the cumulative actual lead.
　This is obtained by least square method and measured by laser system.
P
　Permissible value.
a
　Actual value.
T
　Specifi ed travel.
　This value is determined by customer and maker as it depends on different application requirements.
E
　Accumulated reference lead deviation.
　This is allowable deviation of specified travel. It is decided by both of the   accuracy grade and effective thread length.
e
　Total relative lead variation
　Maximum width of variation over the travel length.
e300
　Lead deviation in random 300 mm.
e2π 　Lead deviation in random 1 revolution 2π rad.

Accumulated reference lead deviation (±E) and total relative variation (e)

Unit：μm

Effective thread length (mm) GRADE Co C1 C2 C3 C4 C5
OVER UP TO E e E e E e E e E e E e
  315 4 3.5 6 5 8 7 12 8 12 12 23 18
315 400 5 3.5 7 5 9 7 13 10 14 12 25 20
400 500 6 4 8 5 10 7 15 10 16 12 27 20
500 630 6 4 9 6 11 8 16 12 18 14 30 23
630 800 7 5 10 7 13 9 18 13 20 14 35 25
800 1000 8 6 11 8 15 10 21 15 22 16 40 27
1000 1250 9 6 13 9 18 11 24 16 25 18 46 30
1250 1600 11 7 15 10 21 13 29 18 29 20 54 35
1600 2000     18 11 25 15 35 21 35 22 65 40
2000 2500     22 13 30 18 41 24 41 25 77 46
2500 3150     26 15 36 21 50 29 50 29 93 54
3150 4000     32 18 44 25 60 35 62 35 115 65
4000 5000         52 30 72 41 76 41 140 77
5000 6300         65 36 90 50 95 50 170 93
6300 8000             110 62 120 62 210 115
8000 10000                 157 75 260 140

Variation in random 300mm (e300) and wobble (e2π)

e300 Unit：μm
CRADE Co C1 C2 C3 C4 C5 C6 C7 C10
JIS 3.5 5   8   18   50 210
PMI 3.5 5 7 8 12 18 25 50 210
e2π Unit：μm
CRADE

Co

C1 C2 C3 C4 C5
JIS 3 4   6   8
PMI 3 4 4 6 8 8