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Creating flat state

R

rayi123

New member
Dear All,


I am not ablee to create a flat state of the attached sheet metal part. Whatever edges or plane I select as fixed geometry, I am getting the error message as"Inappropiate geometry selected". Which edge or plane should I select as fixed geometry? Please help me.





Thanks and Happy New year in Advance!!


Regards


Rayin
 
I think in this case you may have to select the verticle edge when the "conic" stops. When I made a similar part I was able to unbend it by selecting one of those edges. If not, I would have to see the part to figure it out.
 
Hi rayi 123,

In your config.pro, if you set the option mesh_spline_surf to yes, you will see that your surface is construct by spline. When the surface is made by spline, ProEngineer can't unbend it.

What you can do is copy the surface, then use the flatten quilt function in the advanced menu. (See attachment)

Olivier

2008-12-31_105351_prt0006.prt.rar
 
Olivier,


I'm pretty sure I've seen a PTC tech doc that states what you say about
spline surfs. It is not (maybe no longer?) true. Pro/E can do flat
patterns of developable spline surfs.
_ _ _


Rayin,


You don't have a developable sheetmetal part.


Google search: gaussian developable
http://mathworld.wolfram.com/DevelopableSurface.html
http://www.rhino3.de/design/modeling/developable/
[url]http://www.gtwiki.org/mwiki/index.php?title=Developable_Surf aces[/url]
plus lots more.


Is this a 'design effort' or a 'figuring it out' deal? You need to make some
compromises to get a decent developable part.


2008-12-31_142837_prt0006a--wf2--.prt.zipmay help.
Edited by: jeff4136
 
... or ...
2009-01-01_183202_prt0006b--wf2--.prt.zip
2009-01-01_183248_prt0006c--wf2--.prt.zip
... these. Developable surf definition is pretty interesting stuff
especially when you get into more complex shapes. Something I wish
I understood more about.


It's sorta interesting to register the three parts in an assembly and
compare the flat patterns. Also, try offseting a quilt to neutral axis
and flatten the quilt. Pro/E's flatten quilt function is a pretty
rough approximation even at max resolution with developable quilts.
(Just something to keep in mind, as is the by guess and by golly K
factor you'll be using for sheetmetal mode flats.)
 
Hi Jeff,

The answer witch I provided was an answer that I got from a previous call that I post at PTC

You made two other model...
b : ends have spline, this is why you must use special unbend for them
c : you don't have spline wich is really good!!!

I just didn't check to do the Rayi's part by another way to avoid the spline which have probably done by the blend feature :(

Olivier
 
Olivier,


> b: ends have spline ...


Thanks for pointing that out.
It made me question things I thought I knew and I see I was
mistaken. The problem (for me) is the terminology used.
All of those surfaces are 'spline' (vs. analytic) surfaces.
I (guess I) see that the term "spline surface" has a special
meaning in context of the sheetmetal environment and functions.
I'll have to be careful about assumptions, there may be other
situations where some special meaning applies and will get me
in trouble.


Anyway, I reworked the 6b model. As part of the investigation
I also created the 6d model. I've never used a sectional Unbend
except for relatively small surfaces like flanges and was not
aware that the resulting flat pattern from a developable surface
would have the errors shown when compared to the others in an
assembly. I'd have been very embarrassed to send something like
that out to cut.
2009-01-03_030237_prt0006b2--wf2--.prt.zip
2009-01-03_030409_prt0006d--wf2--.prt.zip
 
Dear All,


Thank you for all the replies. It was double new years here in Middle East. So there was some off days.


Dear Bobmann, I tried both the vertical edges as well.


Gentleman Olivier1979, in my conig.pro, mesh_spline_surf = no.


The part is a cover of a planetary mixer, original cover is moulded one. As it is broken, would like to replace with sheetmetal cover.


Regarding other posting, Ididnot not open the attachments. Let me try it out and will soon let you know.


Please note I am using wildfire 2.0


Thanks again for all the guys (gals as well)


Regards


Rayin
 
And I learned something as well, so I guess we're good all around.
smiley1.gif
 
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