CNC machining tolerance table is necessary for CNC workers

2021.07.07

Free tolerance table

1. Limit deviation value of linear dimension (GB / t1804-2000) (mm)

Tolerance class	Basic dimension segmentation
	0.5~3	＞3~6	＞6~30	＞30~120	＞120~400	＞400~1000	＞1000~2000
precise f	±0.05	±0.05	±0.1	±0.15	±0.2	±0.3	±0.5
Middle m	±0.1	±0.1	±0.2	±0.3	±0.5	±0.8	±1.2
Rough e	±0.2	±0.3	±0.5	±0.8	±1.2	±2	±3
Coarsest v	--	±0.5	±1	±1.5	±2.5	±4	±6

2. Limit deviation of rounding radius and chamfering height (GB / t1804-2000) mm

Tolerance class	Basic dimension segmentation
	0.5~3	＞3~6	＞6~30	＞30
precise f	±0.2	±0.5	±1	±2
Middle m
Rough e	±0.4	±1	±2	±4
Coarsest v

3. Limit deviation value of angle dimension (GB / t1804-2000)

Tolerance class	Basic dimension segmentation
	~10	＞10~50	＞50~120	＞120~400	＞400
precise f	±1°	±30′	±20′	±10′	±5′
Middle m	±1°	±30′	±20′	±10′	±5′
Rough e	±1°30′	±1°	±30′	±20′	±10′
Coarsest v	±3°	±2°	±1°	±30′	±20′

4. The form and position tolerance without indication shall be in accordance with GB / t1184-k

4.1 tolerance values of straightness and flatness (GB / t1184-1996) (mm)

Tolerance class	Basic dimension segmentation
	≤10	＞10~30	＞30~100	＞100~300	＞300~1000	＞1000~3000
H	0.03	0.05	0.1	0.2	0.3	0.4
K	0.05	0.1	0.2	0.4	0.6	0.8
L	0.1	0.2	0.4	0.8	1.2	1.6

4.2 undeclared tolerance value of verticality (GB / t1184-1996) (mm)

Tolerance class	Basic dimension segmentation
	≤100	＞100~300	＞300~1000	＞1000~3000
H	0.2	0.3	0.4	0.5
K	0.4	0.6	0.8	1
L	0.4	1	1.5	2

4.3 tolerance value of symmetry without indication (GB / t1184-1996) (mm)

Tolerance class	Basic dimension segmentation
	≤100	＞100~300	＞300~1000	＞1000~3000
H	0.5
K	0.6	0.8	1
L	0.6	1	1.5	2

4.4 undeclared tolerance value of circular runout (GB / t1184-1996) (mm)

Tolerance class	Basic dimension segmentation
H	0.1
K	0.2
L	0.3

3. surface roughness

The surface of the part shall be marked with the grade of roughness. If more surfaces have the same surface roughness level, they shall be marked in the upper right corner of the drawing and the words "rest" shall be added.

The selection of roughness grade can be determined according to the working requirements and Dimension Accuracy grades of each surface. Under the condition of meeting the working requirements, the grade shall not be increased arbitrarily.

1) Selection value of sampling length and evaluation length (gb/t1031-1995)

Ra (μm)	Rz (μm)	Sampling length l(mm)	Evaluation length l n(mm)
＞0.003~0.02	＞0.025~0.10	0.08	0.4
＞0.02~0.10	＞0.1~0.50	0.25	1.25
＞0.1~2.0	＞0.50~10.0	0.8	4.0
＞2.0~10.0	＞10.0~50	2.5	12.5
＞10.0~80	＞50~320	8.0	40.0

2) Value of arithmetic mean deviation Ra of contour (GB / t1031-1995)（ μ m）

Series 1: 0.012, 0.025, 0.050, 0.10, 0.20, 0.40, 0.80, 1.60, 3.2, 6.3, 12.5, 25, 50, 100

Series 2 0.008, 0.010, 0.016, 0.020, 0.032, 0.040, 0.063, 0.080, 0.125, 0.160, 0.25, 0.32, 0.50, 0.63, 1.0, 1.25, 2.0, 2.5, 4.0, 5.0, 8.0, 10.0, 16.0, 20, 32, 40, 63, 80

Note: try to choose the first series

3) Value of maximum height RZ of contour (GB / t1031-1995)（ μ m）

Series 1: 0.025, 0.050, 0.100, 0.20, 0.40, 0.80, 1.60, 3.2, 6.3, 12.5, 25, 50, 100, 200, 400, 800, 1600,

Series 2 0.032, 0.040, 0.063, 0.080, 0.125, 0.160, 0.25, 0.32, 0.50, 0.63, 1.0, 1.25, 2.0, 2.5, 4.0, 5.0, 8.0, 10.0, 16.0, 20, 32, 40, 63, 80125160250320500630

Welcome to visit our Alibaba

https://dgmtwj.en.alibaba.com/?spm=a2700.7756200.0.0.622571d2XUN8qD

Previous:How much do you know about the heat treatment process of 45 steel and 40Cr steel?

Next:10 summary of CNC machining experience, what is CNC machining?

中 | EN
+86 15362887736

CNC machining tolerance table is necessary for CNC workers

Related Information