half viror development

[Christian76]

Hi.
Surely we're wrong.. .
a tube created by extrusion of concentric circles, cut half by length, is not developed properly.

trying to create a sketch,
-external circle of diameter d
- inner circle to create thickness
-including sketches
- extrude n
- to allow the subtraction extrusion by half a pipe
-extrusion of subtraction
-transformation of sheet metal piece with thickness specification
- Flat model

to us the development does not return (but not for some millimeter... Like almost half!)
if I develop all the pipe with the usual "invisible" cut the development is correct.

Does anyone want to do a test?

If I didn't explain well, excuse me and insult me, I'll try to explain better:biggrin:

:finger:

 

[Marco74]

I am not an inventor expert, but it seems that the "k" factor is not correct, you have to use 0.5 as if you do the development manually.

 

[Christian76]

Okay, that could be,
But how is it possible that if the pipe is whole the development is correct?

 

[Tarkus]

the factor k in the displacement is 0,5; without if and without ma. there are several discussions regarding that confirm it.
As for the development of half pipe, I wanted to try: to me gives equal measurements, so; are you sure to cut with a plan that passes exactly in the center?
or even:the small cut of division (extrusion of subtraction) to allow the performance is symmetrical compared to the pipe center or is on one side? This could be the difference you find...

 

[Christian76]

I don't understand. .
that day we tried in 2 the same thing on different pcs but with the same result.
Now I tried... and it's right!
I reopen the incriminated file and... wrong... It's like he's doing an automatic resize on development.

Boo!

Thanks cmq

 

[sampom]

the factor k in the rolling is 0.5; without if and without but.....

Well... I wouldn't be so absolute :biggrin:
we say that it is around and for calculation it is acceptable to use that, at least within certain "small" thicknesses. if you go up a lot things change.

greetings
Marco:smile:

 

[Tarkus]

Well... I wouldn't be so absolute :biggrin:
we say that it is around and for calculation it is acceptable to use that, at least within certain "small" thicknesses. if you go up a lot things change.

greetings
Marco:smile:

:redface:I have no experience of rolling for thicknesses over 50 mm, but until these thicknesses the factor k=0,5 works, if then arise other factors on the deformation during the rolling, I do not know them.
Maybe if you have knowledge of correctives or other to factor k for larger thicknesses, postal ones that could do convenient....:smile: