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Sheet Metal Bend Allowance Calculator: Premium Tool

Looking to learn more about bend allowance and how it can help you determine the length of sheet metal after bending? Look no further than this comprehensive guide from MachineMfg.

Whether you’re a seasoned mold designer or a new press brake operator, this article has everything you need to know about calculating bend allowance and bend deduction values.

From the statistical data used to determine the bending allowance value to the various calculation methods available, this guide covers it all.

Plus, with a handy bend allowance chart for both mild steel and stainless steel materials, you’ll be able to quickly and easily determine the bending angle, V opening, inner radius, and more.

And for those just starting out, a bend allowance calculator has been created to help make your daily work easier.

So whether you’re looking to improve your existing skills or just starting out in the world of sheet metal fabrication, this guide is the perfect resource for you.

I. What Is Bend Allowance?

The bending allowance is a value used to determine the length of the sheet metal after bending.

It varies based on the material, thickness of the sheet, and type of bending die used.

The bending allowance is a statistical value that is derived from the experience and repeated verification of experienced mold designers over the years.

Mold designers can use the calculation formula directly to obtain the unfolding plate size of the bent structure, which is based on the bending allowance data.

II. Bend Allowance Calculation Method

Bend allowance and bend deduction calculations are methods that can be used to determine the length of sheet metal raw materials in the flat form, so as to obtain the desired size of the bending part.

See also  Pipe Bending Torque Calculations: Detailed Guide

Bend allowance calculation method:

The following equation is used to determine the total flattening length when the bending allowance value is used:

Lt = A + B + BA

Wherein:
·Lt is the total flat length
·A and B are shown in the figure
·BA is the bending allowance value

Bend deduction calculation method:

The following equation is used to determine the total flattening length when using the bend deduction value:

Lt = A + B – BD

Wherein:
·Lt is the total flat length
·A and B are shown in the figure
·BD is the bending deduction value

Other calculation methods for determining the flat length of sheet metal raw materials include using a bending allowance chart, the K-factor, and bending calculations.

For new press brake operators who may not know how to calculate the bend allowance, a bend allowance calculator has been created to help make their daily work easier.

To learn more about bend allowances, you can also watch a video on the subject.

Further reading:

III. Bend Allowance Chart

1. Bend allowance chart for SPCC (mild steel)

MaterialThicknessBending angleV openingInner radiusBends Allowance
SPCC0.590V40.50.95
1000.73
1350.3
1750.03
  
SPCC0.590V50.51.03
1000.79
1350.33
1750.03
  
SPCC0.590V60.51.1
1000.85
1350.35
1750.03
  
SPCC0.690V40.51.08
1000.83
1350.35
1750.03
  
SPCC0.690V50.51.15
1000.89
1350.37
1750.03
  
SPCC0.690V60.51.23
1000.95
1350.39
1750.03
  
SPCC0.890V60.51.49
1200.73
1350.47
1500.25
  
SPCC0.890V801.64
1200.81
1350.52
1500.27
  
SPCC0.890V1001.79
1200.88
1350.57
1500.3
  
SPCC190V1002.05
1001.58
1201.01
1350.62
1750.06
SPCC190V801.9
1001.47
1200.93
1350.6
1750.05
SPCC190V601.74
1001.35
1200.86
1350.56
1750.05
SPCC1.290V101.42.31
1001.78
1201.13
1350.73
1750.06
SPCC1.290V81.42.15
1001.66
1201.06
1350.69
1750.06
SPCC1.290V61.42
1001.55
1200.98
1350.64
1750.05
SPCC1.590V61.72.36
1001.82
1201.16
1350.75
1750.06
SPCC1.590V121.72.8
1002.17
1201.38
1350.89
1750.08
SPCC1.590V101.72.65
1002.05
1201.31
1350.85
1750.07
SPCC1.590V81.72.5
1001.94
1201.23
1350.8
1750.07
SPCC290V1023.29
1002.54
1201.62
1351.05
1750.09
SPCC290V1223.44
1002.66
1201.69
1351.1
1750.09
SPCC2.590V183.034.6
1003.56
1202.26
1351.47
1750.12
SPCC2.590V123.034.15
1003.21
1202.04
1351.32
1750.11
SPCC2.590V103.034
1003.09
1201.97
1351.28
1750.11
SPCC390V183.133.135.22
1004.03
1202.57
1351.66
1750.14
SPCC390V123.134.78
1003.69
1202.35
1351.52
1750.13
SPCC390V103.134.63
1003.58
1202.28
1351.48
1750.13

2. Bend allowance chart for SUS (stainless steel)

MaterialThicknessBending angleV openingInner radiusBends Allowance
SUS0.59040.61.04
1000.79
1200.48
1350.3
1750.04
SUS0.59050.61.15
1000.88
1200.54
1350.33
1750.04
SUS0.59060.61.27
1001.13
1200.59
1350.37
1750.04
SUS0.69040.61.16
1000.88
1200.54
1350.34
1750.04
SUS0.69050.61.27
1000.97
1200.59
1350.37
1750.04
SUS0.69060.61.38
1001.05
1200.64
1350.4
1750.05
SUS0.89041.11.4
1001.06
1200.65
1350.4
1750.05
SUS0.89051.11.51
1001.15
1200.7
1350.44
1750.05
SUS0.89061.11.62
1001.23
1200.75
1350.47
1750.06
SUS19061.91.87
1001.42
1200.87
1350.54
1750.07
SUS19081.92.1
1001.6
1200.98
1350.61
1750.07
SUS1.29061.62.1
1001.59
1200.97
1350.61
1750.07
SUS1.29081.62.32
1001.76
1201.08
1350.67
1750.08
SUS1.290101.62.54
1001.93
1201.18
1350.74
1750.09
SUS1.59082.12.68
1002.03
1201.24
1350.77
1750.09
SUS1.590102.12.9
1002.2
1201.35
1350.84
1750.1
SUS29010 3.49
1002.65
1201.62
1351.01
1750.12
SUS29012 3.7
1002.82
1201.72
1351.07
1750.13

3. Bend allowance chart for SPHC (stainless steel)

MaterialThicknessBending angleV openingInner radiusBends Allowance
SPHC190V101.862.05
1001.58
1201.01
1350.62
1750.06
SPHC190V81.861.9
1001.47
1200.93
1350.6
1750.05
SPHC190V61.861.74
1001.35
1200.86
1350.56
1750.05
SPHC1.290V101.442.31
1001.78
1201.13
1350.73
1750.06
SPHC1.290V81.442.15
1001.66
1201.06
1350.69
1750.06
SPHC1.290V61.442
1001.55
1200.98
1350.64
1750.05
SPHC1.590V121.742.8
1002.17
1201.38
1350.89
1750.08
SPHC1.590V101.742.65
1002.05
1201.31
1350.85
1750.07
SPHC1.590V81.742.5
1001.94
1201.23
1350.8
1750.07
SPHC290V122.013.44
1002.66
1201.69
1351.1
1750.09
SPHC290V102.013.29
1002.54
1201.62
1351.05
1750.09
SPHC2.590V1834.6
1003.25
1202.26
1351.47
1750.12
SPHC2.590V1234.15
1003.21
1202.04
1351.32
1750.11
SPHC2.590V1034
1003.09
1201.97
1351.28
1750.11
SPHC390V183.15.22
1004.03
1202.57
1351.66
1750.14
SPHC390V123.14.78
1003.69
1202.35
1351.52
1750.13
SPHC390V103.14.63
1003.58
1202.28
1351.48
1750.13

4. Bend allowance chart for SECC (galvanized steel sheet)

MaterialThicknessBending angleV openingInner radiusBends Allowance
SECC190V101.92.05
1001.58
1201.01
1350.62
1750.06
SECC190V81.91.9
1001.47
1200.93
1350.6
1750.05
SECC190V61.91.74
1001.35
1200.86
1350.56
1750.05
SECC1.290V101.42.31
1001.78
1201.13
1350.73
1750.06
SECC1.290V81.42.15
1001.66
1201.06
1350.69
1750.06
SECC1.290V61.42
1001.55
1200.98
1350.64
1750.05
SECC1.590V121.72.8
1002.17
1201.38
1350.89
1750.08
SECC1.590V101.72.65
1002.05
1201.31
1350.85
1750.07
SECC1.590V81.72.5
1001.94
1201.23
1350.8
1750.07
SECC290V1223.44
1002.66
1201.69
1351.1
1750.09
SECC290V1023.29
1002.54
1201.62
1351.05
1750.09
SECC2.590V183.034.6
1003.56
1202.26
1351.47
1750.12
SECC2.590V123.034.15
1003.21
1202.01
1351.32
1750.11
SECC2.590V103.034
1003.09
1201.97
1351.28
1750.11
SECC390V183.135.22
1004.03
1202.57
1351.66
1750.14
SECC390V123.131.78
1003.69
1202.35
1351.52
1750.13
SECC390V103.134.63
1003.58
1202.28
1351.48
1750.13

5. Bend allowance chart for aluminum plate

MaterialThicknessBending angleV openingInner radiusBends Allowance
AL0.89040.61.15
1000.81
1200.5
1350.36
1750.03
AL0.89050.61.2
1000.85
1200.52
1350.37
1750.03
AL0.89060.61.25
1000.88
1200.54
1350.39
1750.03
AL19060.61.49
1001.05
1206.5
1350.46
1750.04
AL19080.61.59
1001.13
1200.69
1350.5
1750.04
AL1.29060.91.73
1001.22
1200.75
1350.54
1750.04
AL1.29080.91.82
1001.29
1200.79
1350.57
1750.05
AL1.59081.22.18
1001.54
1200.95
1350.68
1750.06
AL1.590101.22.28
1001.61
1200.99
1350.71
1750.06
AL1.590121.22.38
1001.68
1201.03
1350.74
1750.06
AL290141.63.07
1002.17
1201.3
1350.93
1750.08
AL290121.62.98
1002.11
1201.34
1350.95
1750.08
AL290181.63.25
1002.3
1201.42
1351.01
1750.08
AL2.590182.43.89
1002.75
1201.7
1351.21
1750.1
AL390182.54.5
1003.18
1201.96
1351.4
1750.1
AL3.290182.54.74
1003.35
1202.06
1351.47
1750.12
AL490404.66.77
1004.79
1202.95
1352.11
1750.17
AL6.8908009.412.09
1008.55
1205.27
1353.76
1750.31

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