Sheet Metal Design?

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calgarykev
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Sheet Metal Design?

Postby calgarykev » Thu Nov 28, 2013 6:49 pm

Just curious are there any plans for sheet metal design in FreeCad? While construction tools would be nice, the most important feature for me is flattening to 2D.

Thanks!

Kev
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jriegel
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Re: Sheet Metal Design?

Postby jriegel » Thu Nov 28, 2013 8:01 pm

There was a guy some years ago which did a bit in that direction, but it never made it into master. And at the moment there is no activity there....
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calgarykev
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Re: Sheet Metal Design?

Postby calgarykev » Fri Dec 20, 2013 8:32 pm

Hi Juergen;

I talked this over with one of my guys who is a very capable programer and he is interested in looking at it further with me. Neither of us have experience programming a 3D kernel but we understand what it does quite well.

I don't mean to sound lazy but can you guide us in to where we will find useful information to get started at this? We still need to do a lot of reading of the documentation but we did some browsing on the OpenCascade class reference and didn't find anything in the library with a name that made it obvious we would use it to flatten an object or analyze it features for suitability.

If you can point us to classes that would be useful for this task (or any published code that manipulates the solid in a similar way) we can likely discover paths of progress from there.

I guess what I am looking for is something that reveals the philosophy or process OpenCascade has built in to handle sheet metal objects, if any. Or what functions we could use to determine if the object has a consistent thickness in it's features, how we extract and edge from a user selection, etc.

We will have some time over Christmas to do some studying and assess if we are capable of doing this or not.

Thanks!

Kev
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quick61
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Re: Sheet Metal Design?

Postby quick61 » Fri Dec 20, 2013 8:43 pm

Not sure just how relevant this is to what your wanting to do but might be a place to look / get a hint from - Macro unrollRuledSurface

Mark
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jriegel
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Re: Sheet Metal Design?

Postby jriegel » Fri Dec 20, 2013 10:25 pm

Mhh, that's a bit hard for me. I have no idea what kind of algorithms are used for sheet metal design?
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calgarykev
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Re: Sheet Metal Design?

Postby calgarykev » Fri Dec 20, 2013 10:54 pm

Thanks Mark! This is a starting point. It's a surface so no thickness. If you come across any examples involving solids, I would sure appreciate a link.

No worries Juergen, we will do some digging and see what we can find.

Kev
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quick61
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Re: Sheet Metal Design?

Postby quick61 » Fri Dec 20, 2013 11:20 pm

calgarykev wrote:Thanks Mark! This is a starting point. It's a surface so no thickness. If you come across any examples involving solids, I would sure appreciate a link.

Kev
That's the hat trick isn't it... calculating the material consumed in the bend and adding it to the length, on the proper side of the break, when the part is unfolded. I don't have any links to such at the moment but I'm thinking that I ran across something some months ago. Probably not directly portable to FreeCAD but could give some insight to the math involved. I'll take a look around.

Mark
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tanderson69
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Re: Sheet Metal Design?

Postby tanderson69 » Sat Dec 21, 2013 12:12 am

I haven't seen anything in opencascade pertaining to sheet metal. Are you talking doing a FEA forming simulation, or are you talking about simple linear bends(think angle iron)? I haven't been around the forming simulations in a while, but aren't they still using a surface mesh and not a solid? I don't know of any FEA for sheet metal in the open-source world. I had a friend tell me that the first go around of ls-dyna was in the public domain.....and wiki says it's there http://en.wikipedia.org/wiki/LS-DYNA I looked for it years ago and never found it.

Nobody mentioned romans blog so here. he has a lot of good articles, but I gave you a link to the start of the geometry.
http://opencascade.blogspot.com/2009/02 ... scade.htmlAssuming you have the opencascade doc look for tutorial.pdf modata.pdf modalg.pdf.

as a Die Designer, this intersests me, so fire away with questions and I will answer the ones I can. Good luck.
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quick61
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Re: Sheet Metal Design?

Postby quick61 » Sat Dec 21, 2013 12:42 am

No luck finding any other software (open source) but I did stumble upon a video done for SolidWorks that pertains to sheet metal. Might be of interest to those that are not all that familiar with the process.

Mark

Edit - If anyone want's to know how a Sheet Metal Workbench "should" work, take a look at this page and video
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calgarykev
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Re: Sheet Metal Design?

Postby calgarykev » Sat Dec 21, 2013 1:21 am

I am only looking at linear bends (no FEA). So simple radius and bend allowance/deduction work. Basically press brake and simple turret punch stuff.

Soft-shape forms are not my gig. Even transitions (i.e. HVAC) may have to get left to someone else. But if we can parse the geometry and define a process, people can build on our work. Or if we get interested in the bigger problems as we go along, we may take some on.

The vision I have is to create a flat in a drafting view that will update accurately when the 3D part is changed. We will put in a simple parameter table so people can tweak their allowance/deductions based on their tooling. After that, we can look at utilities to create flanges etc. Truth is for linear bends, basic modeling can create most of the parts anyway.

Keep the info coming! No promises yet. Me and Van have never programmed 3D graphics before. Most of my experience is real time embedded controls over 10 years ago and his is current web database. We've both done some Windows app stuff and he's way better than me. Right now our focus is to learn how to mine the data from the solid and create the geometry through the API. The stuff in the middle and ripping corners we know how to calculate manually so I think we can implement it. The intimidating obstacle right now is learning the kernel library.

Thanks!

Kev