Dan Z. -> K-Factor & Bend Allowance spreadsheet

[Anonymous]

Dan Z., this is especially for YOU. However, it also applies to everyone using Sheet Metal in Inventor: I've created an excel spreadsheet to figure out K-factors and Bend Allowances. Right now it works with "Inches" as the unit of measure. I too have been upset with how complicated it is to modify K-Factors and Bend Tables. I don't use the same equation that Inventor uses, I use this one for Bend Allowance: Bend Allowance = [ ( Thickness x F-Factor ) + (Bend Radius x 1.57 ) ] x ( Bend Angle / 90° ) The F-Factor which is specific to steel, hard brass, copper, and aluminum is 0.64. Use an F-Factor of 0.55 for soft brass & soft copper OR 0.71 for bronze, hard copper, and spring steel. Then, I use this one to determine the K-Factor from the Bend Allowance: Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x Thickness ) ) Re-arranging it to solve for the K-Factor, the equation becomes: K-Factor = [ Bend Allowance / PI x (Bend Angle / 180°) - Bend Radius ] / Thickness There are some other things I threw in to the equations like unit "round-off", and something I call "small bend angle correction". There are also two Bend Tables included - one for the specified Thickness & Bend Radius only, the second includes editable Bend Radii and the specified Thickness. Both go from 0 to 180 degrees in 1 degree increments. These worksheets should be saved as txt files and imported into your current sheet metal style. BUT you've got the option to use just the K-Factor, OR just the Bend Table, Or both (by using different Sheet Metal Styles). Because I don't want anybody tampering with the equations, the worksheet is password protected. I've also hidden the equations for now. This is mainly because I've put a lot of work into it, and I don't want someone suing me if they change something to make it calculate incorrectly. However, I will send an "unprotected" version directly to YOU if you post an email address that I can send to. (feel free to encrypt the address to avoid spammers, but just make the encryption something I can decipher). ... I haven't re-written it to work with "mm" yet, because I don't use those units for sheet metal. However, I think it still works without too much hassle if you just ignore the units. For now, wherever it says "in" think "mm". Obviously, you'll have to use the Custom Thickness feature exclusively. In the case of exporting a bend table, be sure to switch the units in the resulting *.txt file BEFORE importing it into Inventor!! The next version may include a switch for "mm". Please post any questions / concerns / differing ideas to the NEWSGROUP only! Also, be sure to read the instructions tab to learn how to use it and see a list of my assumptions. Best wishes, Tim W.

[Anonymous]

Looks like a nice job Tim. ~Larry "Tim W." wrote in message news:40cf509f_2@newsprd01... > Dan Z., this is especially for YOU. However, it also applies to everyone > using Sheet Metal in Inventor: > > I've created an excel spreadsheet to figure out K-factors and Bend > Allowances. Right now it works with "Inches" as the unit of measure. > > I too have been upset with how complicated it is to modify K-Factors and > Bend Tables. I don't use the same equation that Inventor uses, I use this > one for Bend Allowance: > Bend Allowance = [ ( Thickness x F-Factor ) + (Bend Radius x 1.57 ) ] x ( > Bend Angle / 90° ) > The F-Factor which is specific to steel, hard brass, copper, and > aluminum is 0.64. > Use an F-Factor of 0.55 for soft brass & soft copper OR 0.71 for bronze, > hard copper, and spring steel. > > Then, I use this one to determine the K-Factor from the Bend Allowance: > Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x > Thickness ) ) > > Re-arranging it to solve for the K-Factor, the equation becomes: > K-Factor = [ Bend Allowance / PI x (Bend Angle / 180°) - Bend Radius ] / > Thickness > > There are some other things I threw in to the equations like unit > "round-off", and something I call "small bend angle correction". There are > also two Bend Tables included - one for the specified Thickness & Bend > Radius only, the second includes editable Bend Radii and the specified > Thickness. Both go from 0 to 180 degrees in 1 degree increments. These > worksheets should be saved as txt files and imported into your current sheet > metal style. BUT you've got the option to use just the K-Factor, OR just > the Bend Table, Or both (by using different Sheet Metal Styles). > > Because I don't want anybody tampering with the equations, the worksheet is > password protected. I've also hidden the equations for now. This is mainly > because I've put a lot of work into it, and I don't want someone suing me if > they change something to make it calculate incorrectly. > However, I will send an "unprotected" version directly to YOU if you post an > email address that I can send to. (feel free to encrypt the address to avoid > spammers, but just make the encryption something I can decipher). > ... > I haven't re-written it to work with "mm" yet, because I don't use those > units for sheet metal. However, I think it still works without too much > hassle if you just ignore the units. > For now, wherever it says "in" think "mm". Obviously, you'll have to use > the Custom Thickness feature exclusively. > In the case of exporting a bend table, be sure to switch the units in the > resulting *.txt file BEFORE importing it into Inventor!! > The next version may include a switch for "mm". > > Please post any questions / concerns / differing ideas to the NEWSGROUP > only! Also, be sure to read the instructions tab to learn how to use it and > see a list of my assumptions. > > Best wishes, Tim W. > > > > >

[Anonymous]

Tim, We would sure like to have a copy (with formulas & unprotected). Our "sheet metal" tends to run more on the side of "plate", so we need to expand the table. This is the best example I've run across yet - much better than the stock sample. Thanks in advance, Gary W. Lynn glynn@westerntrailer.com "Tim W." wrote in message news:40cf509f_2@newsprd01... > Dan Z., this is especially for YOU. However, it also applies to everyone > using Sheet Metal in Inventor: > > I've created an excel spreadsheet to figure out K-factors and Bend > Allowances. Right now it works with "Inches" as the unit of measure. > > I too have been upset with how complicated it is to modify K-Factors and > Bend Tables. I don't use the same equation that Inventor uses, I use this > one for Bend Allowance: > Bend Allowance = [ ( Thickness x F-Factor ) + (Bend Radius x 1.57 ) ] x ( > Bend Angle / 90° ) > The F-Factor which is specific to steel, hard brass, copper, and > aluminum is 0.64. > Use an F-Factor of 0.55 for soft brass & soft copper OR 0.71 for bronze, > hard copper, and spring steel. > > Then, I use this one to determine the K-Factor from the Bend Allowance: > Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x > Thickness ) ) > > Re-arranging it to solve for the K-Factor, the equation becomes: > K-Factor = [ Bend Allowance / PI x (Bend Angle / 180°) - Bend Radius ] / > Thickness > > There are some other things I threw in to the equations like unit > "round-off", and something I call "small bend angle correction". There are > also two Bend Tables included - one for the specified Thickness & Bend > Radius only, the second includes editable Bend Radii and the specified > Thickness. Both go from 0 to 180 degrees in 1 degree increments. These > worksheets should be saved as txt files and imported into your current sheet > metal style. BUT you've got the option to use just the K-Factor, OR just > the Bend Table, Or both (by using different Sheet Metal Styles). > > Because I don't want anybody tampering with the equations, the worksheet is > password protected. I've also hidden the equations for now. This is mainly > because I've put a lot of work into it, and I don't want someone suing me if > they change something to make it calculate incorrectly. > However, I will send an "unprotected" version directly to YOU if you post an > email address that I can send to. (feel free to encrypt the address to avoid > spammers, but just make the encryption something I can decipher). > ... > I haven't re-written it to work with "mm" yet, because I don't use those > units for sheet metal. However, I think it still works without too much > hassle if you just ignore the units. > For now, wherever it says "in" think "mm". Obviously, you'll have to use > the Custom Thickness feature exclusively. > In the case of exporting a bend table, be sure to switch the units in the > resulting *.txt file BEFORE importing it into Inventor!! > The next version may include a switch for "mm". > > Please post any questions / concerns / differing ideas to the NEWSGROUP > only! Also, be sure to read the instructions tab to learn how to use it and > see a list of my assumptions. > > Best wishes, Tim W. > > > > >

[Anonymous]

Hello Tim, If you could send an unprotected copy, I would appreciate it. Thanks, Stephen R. srottloff@ no spam etcusa.com "Tim W." wrote in message news:40cf509f_2@newsprd01... > Dan Z., this is especially for YOU. However, it also applies to everyone > using Sheet Metal in Inventor: > > I've created an excel spreadsheet to figure out K-factors and Bend > Allowances. Right now it works with "Inches" as the unit of measure. > > I too have been upset with how complicated it is to modify K-Factors and > Bend Tables. I don't use the same equation that Inventor uses, I use this > one for Bend Allowance: > Bend Allowance = [ ( Thickness x F-Factor ) + (Bend Radius x 1.57 ) ] x ( > Bend Angle / 90° ) > The F-Factor which is specific to steel, hard brass, copper, and > aluminum is 0.64. > Use an F-Factor of 0.55 for soft brass & soft copper OR 0.71 for bronze, > hard copper, and spring steel. > > Then, I use this one to determine the K-Factor from the Bend Allowance: > Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x > Thickness ) ) > > Re-arranging it to solve for the K-Factor, the equation becomes: > K-Factor = [ Bend Allowance / PI x (Bend Angle / 180°) - Bend Radius ] / > Thickness > > There are some other things I threw in to the equations like unit > "round-off", and something I call "small bend angle correction". There are > also two Bend Tables included - one for the specified Thickness & Bend > Radius only, the second includes editable Bend Radii and the specified > Thickness. Both go from 0 to 180 degrees in 1 degree increments. These > worksheets should be saved as txt files and imported into your current sheet > metal style. BUT you've got the option to use just the K-Factor, OR just > the Bend Table, Or both (by using different Sheet Metal Styles). > > Because I don't want anybody tampering with the equations, the worksheet is > password protected. I've also hidden the equations for now. This is mainly > because I've put a lot of work into it, and I don't want someone suing me if > they change something to make it calculate incorrectly. > However, I will send an "unprotected" version directly to YOU if you post an > email address that I can send to. (feel free to encrypt the address to avoid > spammers, but just make the encryption something I can decipher). > ... > I haven't re-written it to work with "mm" yet, because I don't use those > units for sheet metal. However, I think it still works without too much > hassle if you just ignore the units. > For now, wherever it says "in" think "mm". Obviously, you'll have to use > the Custom Thickness feature exclusively. > In the case of exporting a bend table, be sure to switch the units in the > resulting *.txt file BEFORE importing it into Inventor!! > The next version may include a switch for "mm". > > Please post any questions / concerns / differing ideas to the NEWSGROUP > only! Also, be sure to read the instructions tab to learn how to use it and > see a list of my assumptions. > > Best wishes, Tim W. > > > > >

[dzender]

Tim,

Thanks a lot.

Your table looks alot different than inventors samples, which make me wonder even more what the heck inventor looks at when it is reading the table. Currently I use (Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x
Thickness ) ) ) for bend length using the K-factor values .5 and .3333 under certain conditions.

I will try this out and see how it works!

[csmac2004]

I wouldn't mind having a copy, but I can't find where it is posted (the protected version). My email is scott@jireh-industries.com

[Michael Quinn]

Hi Tim
It sounds like we my be able to use this spread sheet. Could you post this for the group or if you are sending copies to others here is my email.
Thanks
Mike
mquinn@dewengineering.com

[Anonymous]

It is my first time using the news group envirenment so hopefully this post goes through. "Tim W." wrote in message news:40cf509f_2@newsprd01... > Dan Z., this is especially for YOU. However, it also applies to everyone > using Sheet Metal in Inventor: > > I've created an excel spreadsheet to figure out K-factors and Bend > Allowances. Right now it works with "Inches" as the unit of measure. > > I too have been upset with how complicated it is to modify K-Factors and > Bend Tables. I don't use the same equation that Inventor uses, I use this > one for Bend Allowance: > Bend Allowance = [ ( Thickness x F-Factor ) + (Bend Radius x 1.57 ) ] x ( > Bend Angle / 90° ) > The F-Factor which is specific to steel, hard brass, copper, and > aluminum is 0.64. > Use an F-Factor of 0.55 for soft brass & soft copper OR 0.71 for bronze, > hard copper, and spring steel. > > Then, I use this one to determine the K-Factor from the Bend Allowance: > Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x > Thickness ) ) > > Re-arranging it to solve for the K-Factor, the equation becomes: > K-Factor = [ Bend Allowance / PI x (Bend Angle / 180°) - Bend Radius ] / > Thickness > > There are some other things I threw in to the equations like unit > "round-off", and something I call "small bend angle correction". There are > also two Bend Tables included - one for the specified Thickness & Bend > Radius only, the second includes editable Bend Radii and the specified > Thickness. Both go from 0 to 180 degrees in 1 degree increments. These > worksheets should be saved as txt files and imported into your current sheet > metal style. BUT you've got the option to use just the K-Factor, OR just > the Bend Table, Or both (by using different Sheet Metal Styles). > > Because I don't want anybody tampering with the equations, the worksheet is > password protected. I've also hidden the equations for now. This is mainly > because I've put a lot of work into it, and I don't want someone suing me if > they change something to make it calculate incorrectly. > However, I will send an "unprotected" version directly to YOU if you post an > email address that I can send to. (feel free to encrypt the address to avoid > spammers, but just make the encryption something I can decipher). > ... > I haven't re-written it to work with "mm" yet, because I don't use those > units for sheet metal. However, I think it still works without too much > hassle if you just ignore the units. > For now, wherever it says "in" think "mm". Obviously, you'll have to use > the Custom Thickness feature exclusively. > In the case of exporting a bend table, be sure to switch the units in the > resulting *.txt file BEFORE importing it into Inventor!! > The next version may include a switch for "mm". > > Please post any questions / concerns / differing ideas to the NEWSGROUP > only! Also, be sure to read the instructions tab to learn how to use it and > see a list of my assumptions. > > Best wishes, Tim W. > > > > >

[Anonymous]

Any chance of a copy - We have all but given up trying to do it ourselves !

thanks

E-mail stuart.wilson@thorlux.co.uk

[Nicholas Webb]

Very impressed with your tables, have you done the mm version yet?

As a relative beginner, where do you put the table so that sheet metal style looks at it?

Cheers
Nick

Ps, can you send a table to edit?

[jmartz13]

Hi Tim,

I have downloaded your spreadsheet am and looking at it, in detail and there is no doubt that it is an excellent tool. There is not a lot of published information out there. Anyway could you email me an unprotected copy that shows your calculations? I am afraid I may have to tweak things to work with the refractory metals that I am dealing with. Thanks much,

J. Martz
jennifer.martz@stc-ma.com

[Slambog]

Is there any way you could add lexan to your material list in your spreadsheet or can anyone tell me what the K-Factor is for Lexan

1/8"-Thick
&
1/16"-Thick

Thanks

[Anonymous]

Try this for K-Factor, generally lexan you have to heat and bend, thus it
becomes "plastic" pardon the pun and doesn't react the same as metal, due to
the temperature involved.

Blair

wrote in message news:5054039@discussion.autodesk.com...
Is there any way you could add lexan to your material list in your
spreadsheet or can anyone tell me what the K-Factor is for Lexan

1/8"-Thick
&
1/16"-Thick

Thanks

[Slambog]

I have that Excel Spreadsheet already, works great.

What I was wondering was Can Tim W. add (Lexan 9034) aka Makrolon GP. material to his spreadsheet for cold forming which you can do on a brake press.

They List K value but thats not K-Factor here.
http://www.sheffieldplastics.com/web_docs/Makrolon_Fabrication_Guide.pdf

Even if Tim W. cannot add this is there anyone here that could possible point me in the right direction to obtain a K-Factor for the material listed about, I am having a tought time tracking it down on google 😞

[Anonymous]

Do the old reverse engineer, cut a strip to a length, bend to a given angle
and measure legs.

Blair

wrote in message news:5054142@discussion.autodesk.com...
I have that Excel Spreadsheet already, works great.

What I was wondering was Can Tim W. add (Lexan 9034) aka Makrolon GP.
material to his spreadsheet for cold forming which you can do on a brake
press.

They List K value but thats not K-Factor here.
http://www.sheffieldplastics.com/web_docs/Makrolon_Fabrication_Guide.pdf

Even if Tim W. cannot add this is there anyone here that could possible
point me in the right direction to obtain a K-Factor for the material listed
about, I am having a tought time tracking it down on google 😞

[myles240]

Could you please e-mail me an unprotected copy of your spreadsheet, it sounds exactly what I'm looking for.

Thanks

Myles

mnemetchek@rmd-engineering.com

[don.kluesner]

Could You Email the unprotected spread sheet to me? this is what I need.

[Frederick_Law]

I doubt he could.

His account is archived.

This post is over 10 years old.