Can't get the correct bend allowances . . . 3

[Psycool]

For the longest time I just left the bend allowance alone when making a sheet metal part, because it looked nice enough. Anyhow, I know I'm supposed to make an excel table to use as a bend table, but I can't seem to get it right. Does anyone know a link to step-by-step instructions, or have the time to walk me through it? I can't find any detailed troubleshooting on my problem in any of the SW guides or anywhere else. K-Factor just isn't cutting it anymore.

Thanks gents.

-Cheers

 

[MadMango]

A basic question that needs to be asked is if this information is going to be used by outside vendors, or an in-house department?

If this information is going to be used for vendor work, the best thing to do is to get with yor vendors and find out what they use. "The attempt and not the deed confounds us."

 

[Psycool]

This is for our own personal use. I know this may sound strange, but we've been making precision sheet metal parts for over 20 years now, calculating (or memorizing) proper bend allowances, etc. However, I just can't GET the Excel file of all the proper bend allowances INTO SolidWorks, so it's not actually getting the data for bending that's the problem, it's the act of importing it into SolidWorks so it will make the parts how we need them to be made. If anyone has a clue, I know it says to make an Excel file, but I've also heard you have to make a *.btl file for it to work, and I've tried both and my format must be wrong or something. Thanks.

-Greg "I am the Alpha and the Omega" ~Xenogears

 

[Nobbyv4]

I too would be interested in any help on created or modifying the bend table in SW2001. I am in the process of learning this software for a sheetmetal company and came across this situation a couple of days ago. At work we have a bend allowance, which is taken from (ie -)the total calculation depending on radius and material used. The K factor in SW is not accurate enough in my limited experiance with SW so far.I've done simple bracket to test the "bend allowance" option and that seems to work, but again I have not used it enough to be 100% sure.

Any info gladly appreciated.

 

[bcolley]

It took me awhile but I have created a working bend table in excel and use it every day to figure flat sizes for parts we design and for parts I import from customers. There is a sample file that solidworks provides and you have to copy it and then fill in your numbers. It can be a frusterating thing but once you get it done it is SOOO nice!! You can find the sample file in:
program files/solidworks/english/sheetmetal bendtables
there is a bend deduction chart and a bend allowance chart available. The numbers all just depend on your bending. I hope I can be of some more assistance.

 

[sirlafflot]

Cant help from asking my question here , so forgive me if I am being too forward , but I have a family business , and we do precision sheetmetal since 1963 , and I would be the first to admit that we have much to learn , as far as making flawless calculations , that we can proove out , when we get to the Pressbrake. I agree that it may be the formulas are not precise enough , but I have also chalked up much of this inaccuracy to worn tooling etc... In other words , an .031 radius punch , after some use will increase the radius some , just from wear . I also know that , coining produces different results from air bending when calculating propper flat pattern layouts .
Is there any chance , any of you would be willing to share your findings or spreadsheets with me , as I can test them daily in our environment , and maybe someday get closer to a definitive answer . If this is not possable , because you have policy that doesnt allow you to share this info , I understand , and forgive me for asking . But like all of you , I'm sure , my goal is to just make everyday routines , easier so I can address other fires that will , without a doubt crop up !

 

[bcolley]

The formula we use for figuring radius bends is
Bend allowance =
(.01743xIR)
+
(.0078 x T)
x
Angle


IR=inside radius
T=thickness of material
This is very accurate for our brakes but I know every shop seems different as on several occasions we have gotten so busy that we had to outsource things to 2 other sheetmetal shops in town and neither could use the same flat size as us.

 

[Nobbyv4]

I have a copy of a set of bend deduction parameters for Amada tooling, and I am at present inputing this into an Excel spread sheet. Am I to understand from the comments by bcolley that I should be inputing these paremeters into a template Excell file in S-works? I'll have another look when I get time and post the results.

 

[bcolley]

Get into excel and go to
Program Files\SolidWorks\lang\english
You should see a sample bend deduction table. You can make a copy of that and then enter your numbers/formulas for your tooling, save it in this same area. Then when you have a part go to the sheetmetal properties and pick your new bend table.
You will need a different table for each kind of material (crs, s/s, alum etc.)
Feel free to email me if you need more help.
bcolley@dawsonmetal.com
-Brooke

 

[Nobbyv4]

Thank for the info and offer, I'll give it a go first.

 

[bcolley]

Hello,
Someone emailed me yesterday with questions regarding this thread. I was just getting ready to leave for the night. My intentions were to send a reply this morning. When I got to work I found out that work was done on our network last night and my inbox was deleted!! So I'm sorry that I can't email you back, please re-send your question!
Brooke

 

[swapnilengineer]

Hi All,

Can anybody give me an idea to use rip for legacy data in solidworks? Most of the times it fails. Any alternative methode will be appriciated.


Swapnil.

 

[MadMango]

I want to resurrect this thread, becuase much like the original poster, we have been using k-factor for a very long time. Now it seems, for some reason, that k-factor is no longer giving us accurate results that were appearently acceptable in the past.

We are now looking into Bend Tables. From what I under stand, you need different tables based on material (SST, HRPO 1008, CRS 1018, SST 304).

What about different tables based on bends that are obtuse or accute?
What about a model that has bends that are obtuse and accute? Can you apply several different bend tables to the same model?

Thanks all.

Wanna Tip? faq731-376
"Probable impossibilities are to be preferred to improbable possibilities."

 

[TheTick]

MadMango:

What do you mean, "k-factor is no longer giving us accurate results that were appearently acceptable in the past"? Are the parts not correct, or is SW not calculating correct values per the thickness, radius, K-factor, and angle?

I just ran a series of tests comparing the SW calculated values to the values calculated by hand using Allowance=(180/pi*angle)*(R+k*T). I ran through numerous combinations of angle, thickness, radius, and K-factor. No errors.

Perhaps something is amiss with your tooling or material. Grain direction, perhaps?

I may make you feel, but I can't make you think.

 

[MadMango]

It's not grain direction, that's for sure. We had our sheet metal supervisor (20yrs exp) work with Engineering to come up with an acceptable K-factor. This was years ago when we first got SW96+.

Apparently, for thhe last several years (at least 18 months) the guys programming from our flatpattern DFXs have been "tweaking" the DXFs so the parts will be made correctly. I'm not sure why they never bothered to tell us.

Anyways, this SM Supervisor gave us a value of .430 to use a k-factor, saying it was generic enough to use with all materials and bend radii. Later, (maybe 3 years ago) this value was updated to .434. It was suppose to be "more better".

Fast-forward to today, and for some reason, if they don't tweak out flat patterned DXFs, we'll have errors of up to 1/8 on a part. The feeling is k-factor is too generic, and we would be better off using Bend Tables.

Wanna Tip? faq731-376
"Probable impossibilities are to be preferred to improbable possibilities."

 

[Standing]

Brooke,
Deleted messages are sent to the Deleted Items folder. They are not removed permanently unless they are deleted from the Deleted Items folder.

Bradley

 

[JNR]

Reference the "how to" of getting tables to work. Go beat on your VAR's door - that's what you are paying you annual support for. (You are pay support aren't you? - please say "yes".)

3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[MadMango]

JNR, there's not a problem with SW, at least I don't think so. This is a manufacturing problem. I am asking 2 things here:

1) Do I need a seperate bend table for obtuse and accute bend angles?
2) Can I apply more than 1 bend table to the same model with sheet metal features?

My company has stayed current with subscription since SW96+. Well worth the trouble.

Wanna Tip? faq731-376
"Probable impossibilities are to be preferred to improbable possibilities."

 

[Htaed]

I've wriiten a program for figuring BA and press brake set back. The formulas used in it are taken from over 10 years experience in the metal fabrication industry. It is used in the plant I work for and the engineers there found it very useful. If anyone is interested in it please let me know. I'd be happy to share.

htaed@comcast.net

 

[WDickman]

In true SW tradition, the Excel bend files don't refer to sheet metal gage sizes & use fractions for the bend sizes. Anyone hazard a guess as to why this is? Accuracy does not live with fractions.