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is it a bug?

puzzled
1-Newbie

is it a bug?

Whenever i create a die/punch form on sheet metal...its weight increases then normal sheet. I dont understand how the weight increases than original sheet? either it can go constant or decreases i guess? Please correct me if i am going wrong!!!


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35 REPLIES 35

the overall length of your plate remains the same...the punch or die you add just adds extra material.

that is the reason the weight increases.

But it shouldnt be like that...we create a punch or die from the exissting sheet!!!...Anyway to overcome this?

jehan that you do practically...but in proe that is not the case...

in proe the punch you add becmoes the extra material.

i don't think modeliing software would have a solution...

Hmmm it seems so ... May be there is an extension available for all such question that is FTI blank..the video shows the same way we want it...

but i don't think FTI blank gives a demo version...

Nope i have just been through some of its videos and website stuff ...

verifed in solidworks..yes the overall weight does increase slightly depending on the size of punch.

First of all, I suggest making a support case of this and if they say it works to the product specification, escalate it and ask to see that specification. I don't know how -anyone- could justify this behavior!

As for a work around, try using quilt forms.

TomU
23-Emerald III
(To:TomD.inPDX)

From a Creo perspective, if you are adding material to the CAD model, the mass is going to go up. Creo is not doing forming simulation. The material thickness is maintained. If the surface area goes up, the mass is going to go up.

Keep in mind too that if the specification doesn't explicitly say something different should occur, then by definition it is automatically "to spec".

"To spec" does NOT necessarily equal "makes sense", "intuitive", "desirable", or anything else.

TomD.inPDX
17-Peridot
(To:TomU)

I see what you are saying; the additional material is not the form itself, but the area of the deformed region is increased.

I was thinking the mass of the tool was being added, and that doesn't make sense at all!

dgschaefer
21-Topaz II
(To:puzzled)

I think sheet metal in general is not 100% accurate in terms of mass.The bends have constant wall thickness, for example, instead of being thinned. buit those are somewhat trivial in comparison.

You can create an analysis feature in ahead of your die/punch features (assuming they are at the end of the tree) that captures the part mass and assigns it to a parameter. Creo also can assign mass to a part and use that in assembly level mass properties calculations. There may be a way to use the analysis feature true mass calculation to drive the assigned value.

A bit if work, and sorta clunky, but you may get it to work. I'd agree, the software should handle this better.

--
Doug Schaefer | Experienced Mechanical Design Engineer
LinkedIn

Yes i agree its not 100% accurate but flattening form dimension and mass are major concerns that cad software should add.I mean on sheet you can have no. of punches....you can ignore those parameter for 1-2 but not for 20-30 which makes a vast difference. Now to do same in creo we have to buy another extension. i had been at Solid edge ST7 seminar yesterday where they agreed to the fact that flattening the form will add into sheetmetal dimension as customer required and yes its inbuilt functionality.

You could take the mass data from the flat state. The flat pattern feature has the option to flatten all forms. Actually, this would make for a nice improvement where one could switch the mass properties (volume) to read the volume at the flat pattern feature (since this is -always- at the end of the tree) if it exists. A simple smtl config.pro option would manage this. Or provide a separate mass property entry for the flat pattern state in the software. This one should be very easy to implement if anyone can decide on the best way to handle it.

if you can, vote here: Calculate sheetmetal mass properties in the flat pattern state

dschenken
21-Topaz I
(To:puzzled)

What other extension would you buy? What function do you think is missing?

If you need an estimate of the weight, use the weight of the flat pattern.

If weight is important, weigh each part when it is formed. Unless tighter control than usual is used on metal thickness, this will most often be a larger contributor. For example, a part made of 12ga steel is going to be 18% heavier at the max thickness versus the min thickness.

yes the blank feature has been added in st7..there is a video on youtube also.

"flatten quilt" option might help you to get the flat blank size..taking into account the punch also.

flatten quilt in sheet metal? Couldnt locate the command!!

you have to copy the surface that you want flatten and then take copied surface into part modelling to use the fallten quilt option

and then adding the thickness and giving density would give you the weight also

hmmmm seems like giving a try..i ll do it and let u know the results (y)

Flatten quilt will not account for bend allowance.

you mean to say the bedn radius?

No-no... The Y or K factor compensation. What I normally refer to "stretch and crush" There is that median line through the material that maintains the accurate length through a bend, where, toward the outside of the bend radius, the material stretches... and toward the inside of the bend radius, the material crushes. The two sides of the bends radius have significantly different surface areas.

I'm not interested in sheet metal work. Your question "Is it a bug?" wasted my time. Please include some specific information in your title.

How many post did you read before you realized it wasn't interesting to you?

It's his first post. Maybe he signed up just to make it. Possibly thought it was about insects and arachnids.

probably very less time wasted as compared to commenting then again revisiting the same post for replying and may be the third time you will again visit to justify!!

dschenken
21-Topaz I
(To:puzzled)

You asked for help, said the answer was inadequate.

I asked for clarification which you have now rudely answered.

What is the answer you are looking for?

commenting would have consumed more time than realizing that you waste time coming on this page

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