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Sheet Metal Bend Allowance

Solution Partner Pioneer Solution Partner Pioneer
Solution Partner Pioneer

Dear all;

I have some question form customer.

  1. How can I set bend Allowance in Solid Edge? I think they want to fix length of Flange.
  2. When I modify some radius of flange. I can set neutral factor in specifically flange?

Thank you.


Re: Sheet Metal Bend Allowance

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

Hi there @Famer,


Yes, you can modify individual bends to have different "Bend Radius" & "Neutral Factor", within the "Bend Options" you can overide the defaults.

Flange lengths should already be fixed, by the design model, the bend is  where the variable length occurs.



Sean Cresswell
Design Manager Streetscape Ltd
Solid Edge 2019 [MP8] Classic [x3 Seats - Cloud Enabled]
Windows 10 - Quadro P2000

Betreff: Sheet Metal Bend Allowance

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

Hi @Famer




I think the best would be to use the ISOTable.PZL


See in the Custom folder of Solid Edge Installation under SheetMetal and ISOtable.


There is a regsitration.exe which much be executed once per computer with admin privileges.


Then You see a table.txt file where You can define Your wanted bend values



Re: Sheet Metal Bend Allowance

Honored Contributor
Honored Contributor

Sean is correct. R and K determine BA, T also is part of the calulations.


Solid Edge presents it like this 

Siemens Documentation: Sheet Metal Bend Formulas

  • PZL = * (BR + (NF * THK)) * BA / 180


    PZL = Plastic Zone Length

    BR = Bend Radius

    NF = Neutral Factor

    THK = Material Thickness

    BA = Bend Angle


Where as I typicall use the following definitions:



TMaterial thickness inches    
RInside bend radius inches    
ABend angle Degrees    
K%/100  of T for neutral axisunitlesst/T0.33 is standard 
BABend allowance inchesmaterial around the bend  
BDBend deduction inchesmaterial removed from flat for a bend
LFlat length inches    
SBSetback  inches=T+R   
Formula   GaugeT   
L=X+Y-BD   100.1345   
BA=A(R+KT)/57.2958 120.1046   
BD=2 SB -BA  140.0747   


Now to the real problem. Every combination of machine and material result in a different N and R.

You have to find out how your machine works and the pressure settings used.


Most of the time N=1/3 or 0.33 is good enough. But as you go from 14 gage to 10 gage carbon steel, N moves from 0,33 to 0.4

Betreff: Sheet Metal Bend Allowance

Solution Partner Innovator Solution Partner Innovator
Solution Partner Innovator
Hi @hawcad

What is the function of this table actually? There is no clear documentation on how to use this?

It will be good if you can explain a bit on what for and how to use

Betreff: Sheet Metal Bend Allowance

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

HI @Arisy



there are two tables available for use as PZL.


The ISOtable and the DINtable.


The ISO table has entries for every radius (many radii) and thickness giving the length of the PZL

Using this entries You exactly can define how long the PZL should be for certain conditions.



See the first lines:


# Table.txt - Bend table example data file
# Start comment and blank lines with #
# All units are in millimeters and degrees for this example
# The format for a table entry is:
# Material Thickness, Bend Radius, Bend Angle, Length of bend in the flat
# Each each value must be seperated by a comma.
# Add/define all values for a one thickness before adding values for a new thickness.
# NOTE1: These values are for example use only. Supply your own values as needed.
# NOTE2: You can have as many thickness tables as you need but the maximum number of
# table entries per thickness is 25. To change this limit you will need to edit
# the VB program example.
# NOTE3: The decimal symbol character must be a point (.) character.
# Regional settings for the computer are not supported for this file.
0.50, 0.75, 90, 1.437
0.50, 1.00, 90, 1.830
0.50, 1.50, 90, 2.615
0.50, 2.00, 90, 3.401
0.75, 0.75, 90, 1.570
0.75, 1.00, 90, 1.960
0.75, 1.50, 90, 2.745
0.75, 2.00, 90, 3.530



The entries in the lines are explained well on top




The other table - and this is my favorite - is the IDN table using the DIN formular for steel ssheet metal parts calculating the N factor for every single bend using the current radius and sheet thickness.

So if You have multiple radii in Your part, this IMHO is the easiset to use.