How to roll out this part ?

[steveastro]

I've got this design for a hollow shell, through which straight pipes will pass, so any holes not on axis are not circles in the flat sheet from which the part will be made. How do I roll this part out to make a production drawing, or pattern for a CNC laser ? Its got me stumped !

 

[Oldbelt]

You calculate the lenght of the hole "diameter" at the cylindrical surface, you know dia. of the holes in the aksial direktion,
thats your pipe dia.
Then make a flat sheet and sketch elipsies with a / b akses as you have calculated.

 

[steveastro]

You calculate the lenght of the hole "diameter" at the cylindrical surface, you know dia. of the holes in the aksial direktion,
thats your pipe dia.
Then make a flat sheet and sketch elipsies with a / b akses as you have calculated.

Thanks Oldbelt,

I rather hoped there was a direct method - this is what CAD is for. I could do it at a drawing board, pretty easily !

Steve

 

[HaroldL]

You calculate the lenght of the hole "diameter" at the cylindrical surface, you know dia. of the holes in the aksial direktion,
thats your pipe dia.
Then make a flat sheet and sketch elipsies with a / b akses as you have calculated.

Thanks Oldbelt,

I rather hoped there was a direct method - this is what CAD is for. I could do it at a drawing board, pretty easily !

Steve

Steve.
The "direct method" would be for Alibre to create cuts normal to the surface in sheet metal. It's obvious you need a solution now but this was hinted at by Max for v2012 in this post: viewtopic.php?f=1&t=12357&p=74827&hilit=normal+cut#p74827

Let's hope it gets implemented; that would be a real step up for Alibre if they pull it off.

 

[dudley]

The trick is to use polygon shapes to approximate circular holes. This will work as long as a cutout does not cross an edge. I very much hope that flat patterns will be more robust in the next version.

 

[steveastro]

Dudley,
If I were wearing a hat, I'd take it off to you. That is a VERY neat trick, I really didn't know how to do it.l I'd never have thought of using a polygon !!!
Thank you very much. Brilliant work.

Steve