JB/T 4381-1999 This standard is not equivalent to JIS B O410-1978 "General tolerances for metal plate shearing processing". This standard is a revision of JB 4381-87 "Tolerances of punching and shearing blanks". There are slight additions and deletions to the technical content during the revision. This standard specifies the tolerances for the width, straightness, and burr height of metal plates sheared by gantry-type and open-type shears with a thickness of less than 12 mm or blanks for stamping. Mainly applicable to dimensions and elements where tolerances are not noted on drawings. When this standard cannot meet the requirements for sheared plates and stamped blanks or allows larger tolerances than specified in this standard, the dimensional tolerances or technical requirements of the elements should be noted separately. This standard was first published on the year, month and day. JB/T 4381-1999 Limit deviation of punching and shearing blanking without tolerance dimensions JB/T4381-1999 Standard download and decompression password: www.bzxz.net

JB/T4381--1999
Previous
Preface
This standard is a revision of JB4381--87 "Tolerances of Stamping and Shearing Cutting Parts".
This standard is not equivalent to the JIS Japanese Industrial Standard JISB0410-1978 "General tolerances for metal plate shearing processing". This standard has changed from JB4381-87 in the following main technical contents: 1) Contents of Shearing Width Tolerance Table 1;
2) Contents of Shearing Straightness Tolerance Table 2;
3) Shearing Cutting verticality tolerance table 3 content;
4) Shearing burr height allowable value table 4 content. This standard will replace JB4381--87 from the date of implementation. This standard was proposed and centralized by the National Forging Standardization Technical Committee. The main drafting unit of this standard: China YTO Group Corporation Stamping Factory. The main drafters of this standard: Shi Dingyong and Yuan Xiuping. 137
1 range
Mechanical industry standard of the People's Republic of China
Punching and shearing
Limit deviation of unindicated tolerance dimensions
Permissible limit deviation in dimensionswithout tolerance indication for shearing of metal platesJB/T4381
1999
replaces JB381--87
This standard specifies gantry-type and open-type shearing machines with a shearing thickness of 12mm The tolerances of the following metal plates or plates for stamping, straightness, verticality, and burr height. Mainly applicable to dimensions and elements where tolerances are not noted on drawings. When this standard cannot meet the requirements for shear plates and pressed plates or allows the use of larger tolerances than specified in this standard, the dimensional tolerances or technical requirements of the elements should be noted separately. 2 Definitions
This standard adopts the following definitions.
2.1 Shearing width
The distance from the cutting edge of the shearing machine to the opposite edge, as shown in size 6 in Figure 1. 2.2 Shearing length
The length of the plate sheared by the blade of the shearing machine, as shown in dimension L in Figure 1. 2.3 Cutting parts
Product parts cut from the plate. The blocks or strips used for stamping are called shear parts. Cutting parts
Cutting parts
Cut off the edges!
3 Accuracy Levels
Figure 1
Cutting
3.1 The accuracy levels of shearing width tolerance, shearing straightness, and shearing verticality are divided into A and B Two levels. 3.2 The precision grades of shearing burr height are F, M and G. 3.3 Shearing width, straightness and verticality tolerances 3.3.1 Shearing width tolerances are specified in Table 1
National Machinery Industry Bureau approved 1999-06-24 138
Implemented in 200001-01||tt ||Material thickness
Accuracy level
Cut width
120
≥120～350
>350-~1 000
>1 000~2 000
>2 000-~3 150
3.3.2
A
1.6
0.2
± 0.3
±0.5
±0. 8
±1.0
B
±0.5
±1. 0||tt| |±1. 5
±2.0
±2.5
The shear straightness tolerance is specified in Table 2.
Tree thickness
Accuracy level
Cut length
120
>120～350
>350～1 000|| tt||71 000~2000
2 000-3 150
A
0. 2
0.3
0. 4
0.6
0.9
.1.6
B
0.3
0. 5
0. 9
1. 2
1.6
JB/T 4381—1999
Table 1
≥>1. 6~3
A
±0.3| |tt||±0.4
±0.5
±0.8
+1.0
Table 2
B
±1. 0| |tt||±1.5
+2.0
±2.5
±3.0
>1. 6-~3
A
0. 2
0.3
0.5
0.8
1.0
B
0. 3
0.6||tt ||1.0
1.6
2.2
A
>3~~6
±0.7
0. 9||tt| |t1. 6
±2.0
±2.8
B
±1.2
±2. 0
+2.5||tt ||±3.0
±3.5
>3-~6
A
0.5
1.0
1.4
2. 5
2.8
0.8
1.6
2.0
3.0
4.5
Note: This table is applicable to The cutting width is more than 25 times of the plate thickness and the metal shearing parts with a width of more than 30mm. 3.3.3
The shear verticality tolerance is specified in Table 3.
Table 3
Material thickness
Accuracy, etc.
Cut short side length
120
120~350
>350~1 000
≥1 000~2 000
3.3. 4
十
A
0.2
0. 4
1.
2.1
1.6
B
0.6
0.7
1. 4
3.5
The allowable value of shearing burr height is specified in Table 4. Material thickness
0.3
Accuracy level
>0. 3-~ 0. 5
>0. 5~1. 0
>1.0~ 1. 5
>1. 5~~2. 5
>2. 5~ 4. 0
>4.0~~6. 0
>6. 0~8. 0
≥8. 0~12. 0
3.4 ??Measurement method
3.4.1 Shearing width
F
>1 . 6~~3
A
0. 4
0.6
1.3
2.8
Table 4
. 0.03
0.04
0.05
0.06
0.08
50.25
s0.36
0.40
0.50
B
0.7
1.0
1.8
4.3
A
0.7
0.9| |tt||≥36
B
0.9
1.4
1.4
3.5
M
0.05|| tt||0.06
0.08
0.12
0.16
0.37
s0.54
0.60
0.75|| tt||2. 8
5.0
A
A
≥6~12
mm
B
±1.5
±2.5
13.0
3.
±4.0bzxZ.net
mm
6~~12
B
0.6
1.2
1.6||tt| |3.0
3.5
1.0
2.0
2.5
3.5
5.0
mm
> 6～12
A
G
0.07
0.08
0.12
0.18
1.0.32||tt ||s0.50
0.73
o.80
1.00
B
1.1
1.8
4.3| |tt||6.4
mm
139
Close. | |tt | End attachment: When the shear length is not greater than 1500nm, three points should be measured, namely both ends and the middle. Cut edge
3.4.2 Shear straightness
Figure 2
Cut edge
Put the cut piece flat on the inspection platform and measure it with a ruler or square ruler The maximum value of straightness α1 is shown in Figure 3. 3.4.3 Shearing verticality
Put the sheared piece flat on the inspection platform, use one side of the square ruler to close to the long side of the shearing piece, and the other side of the square ruler to the end of the short side of the shearing piece Closely, measure the maximum value of the short side of the shear piece that is not close, which is the shear verticality α2, as shown in Figure 4. 3.4.4 The burr height of the shearing parts
The measurement method of the burr height of the shearing parts can generally be measured with a vernier caliper or a micrometer. Cut edge
Inspection platform
Long edge
4 marks
Cut pieces
Check ruler
Short edge
n
Right square
Figure 3
Figure 4
When using this standard for irrigation, it should be indicated in the drawing or related documents. 140
Cut edge
Cut piece
Inspection platform
Long side
90
Straightedge
Right square
Short side
JB/T4381-1999
4.1 When various sizes or elements are the lowest, just indicate the standard number. Example: Shearing and blanking tolerances are in accordance with JB/T4381-1999. 4.2 When various dimensions or elements are of the same precision level, the standard number and precision grade number can be indicated. Example: Shearing and blanking tolerances are in accordance with JB/T4381-1999-B. 4.3 When various dimensions or elements have different accuracy levels, the tolerance name and elements, accuracy and standard number should be indicated. For example: the shearing width tolerance and straightness are in accordance with JB/T4381-1999-B, and the verticality is in accordance with JB/T4381-1999-A. In the technical documents used for production, the selected precision or value should be indicated according to the tabulated values ??of tolerances and elements. 4. 4
141
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