TERMS OF LINEAR GUIDE
2-12 Model Number Coding
a. Accuracy standard
Unit : mm
ITEM GRADE |
Normal(N) |
High(H) |
Precision(P) |
Super-Precision(SP) |
Ultra-Precision(UP) |
Tolerance of height ( H ) |
±0.1 |
±0.04 |
0 |
0 |
0 |
Tolerance of width ( W ) |
±0.1 |
±0.04 |
0 |
0 |
0 |
Difference of heights (△H ) |
0.03 |
0.02 |
0.01 |
0.005 |
0.003 |
Difference of widths (△W ) |
0.03 |
0.02 |
0.01 |
0.005 |
0.003 |
Running parallelism of BR Block surface |
△C Refer to the below Fig. BG rail length and running parallelism |
||||
Running parallelism of BR Block surface |
△D Refer to the below Fig. BG rail length and running parallelism |
b. Choosing preload
Replacing larger rolling elements helps strengthening the entire rigidity of the
carriage while there exists clearance within ball circulation.
Preload |
Slight clearance/ |
Light preload (Z1) |
medium/ heavy |
Conditions |
1. Light corrosion |
1. Cantilever |
1. Heavy corrosion |
Application |
1.Welding machine |
1. NC Lathe |
1. Machine center |
Increasing preload would diminish the vibration and reduce the corrosion
caused by running back and forth. However, it would also add the workload
within those rolling elements. The greater the preload, the greater the inner
workload. As a result, choosing preload has to consider both how vibration and
preload would affect life and conclude an optimal choice.
Preload grade
C: Basic dynamic load rating | ||
GRADE ITEM |
Symbol |
Preload force |
Clearance |
ZF |
0 |
No Preload |
Z0 |
0 |
Light Preload |
Z1 |
0.02C |
Middle Preload |
Z2 |
0.05C |
Heavy Preload |
Z3 |
0.07C |
Radial clearances
Unit: μm | |||||
Symbol Type |
ZF | Z0 | Z1 | Z2 | Z3 |
BG 15 | 5~12 | -4~4 | -12~-5 | -20~-13 | -28~-21 |
BG 20 | 6~14 | -5~5 | -14~-6 | -23~-15 | -32~-24 |
BG 25 | 7~16 | -6~6 | -16~-7 | -26~-17 | -36~-27 |
BG 30 | 8~18 | -7~7 | -18~-8 | -29~-19 | -40~-30 |
BG 35 | 9~20 | -8~8 | -20~-9 | -32~-21 | -44~-33 |
BG 45 | 10~22 | -9~9 | -22~-10 | -35~-23 | -48~-36 |
Interchangeability
Accuracy |
Non - interchangeable |
Interchangeable |
|||||
UP |
SP |
P |
H |
N |
H |
N |
|
Preload |
|
|
|
|
ZF |
|
ZF |
|
|
Z0 |
Z0 |
Z0 |
Z0 |
Z0 |
|
Z1 |
Z1 |
Z1 |
Z1 |
Z1 |
Z1 |
Z1 |
|
Z2 |
Z2 |
Z2 |
Z2 |
Z2 |
|
|
|
Z3 |
Z3 |
Z3 |
|
|
|
|
ITEM |
Unit: μm | |||||||||
e1 |
e2 |
|||||||||
Z3 |
Z2 |
Z1 |
Z0 |
ZF |
Z3 |
Z2 |
Z1 |
Z0 |
ZF |
|
BG 15 |
|
|
18 |
25 |
35 |
|
|
85 |
130 |
190 |
BG 20 |
|
18 |
20 |
25 |
35 |
|
50 |
85 |
130 |
190 |
BG 25 |
15 |
20 |
22 |
30 |
42 |
60 |
70 |
85 |
130 |
195 |
BG 30 |
20 |
27 |
30 |
40 |
55 |
80 |
90 |
110 |
170 |
250 |
BG 35 |
22 |
30 |
35 |
50 |
68 |
100 |
120 |
150 |
210 |
290 |
BG 45 |
25 |
35 |
40 |
60 |
85 |
100 |
140 |
170 |
250 |
350 |
Cap:
Most chippings are blocked by end seals, but some would stay in the screw
holes. Caps are accessory that can prevent the entry of chippings.
Rail with tapped holes:
Fixing a rail with tapped hole is different from fixing a standard one. A major
strength of it is the shape of the tapped hole (shown as fig.); dust and chippings
would not enter.

Size |
Screw |
Length of thread |
BG 15 |
M5 |
8mm |
BG 20 |
M6 |
10 mm |
BG 25 |
M6 |
12 mm |
BG 30 |
M8 |
15 mm |
BG 35 |
M8 |
17 mm |
BG 45 |
M12 |
24 mm |
d. Accessories of block
Coding of seal end seal side seal inner seal
(top seal)double end seal
(double front seal)scraper
(metal front shield)Not specified ˇ ˇ UU ˇ ZZ ˇ ˇ ˇ DD ˇ ˇ KK ˇ ˇ ˇ SS ˇ ˇ ˇ SD ˇ ˇ ˇ
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