The flat pattern for a hemisphere is a circle. But to get the correct size needed u will need to speak to the experts. Spinning is a bit of a black art. Its a very old method of working metal, and requires lots of knowledge. You might find that they are unwilling to part with this knowledge, and would rather just have the model of the finished item and work it out for you.
Use a drawn part. One company I worked for had to make extinguishers
that were a sphere. We made 2 drawn halves and welded together. Just
draw the shape and let someone like Hudson Tool or Zero Manufacturing
draw the part and worry about how much material is required.
> has anyone done this? i would expect the pattern to look like one of
> those world maps thats all laid out flat. -Joe
We've had to have several parts spun for us. To make the inventor model we simply use a revolve of a profile. We then send the metal spinning company drawings of what we would like. It is up to them to make the result.
We've never had to make a spere, but we have had to make several types of circular fan venturi this way. It isn't that difficult to get this done in Aluminum, but getting a precious metal to do it in a very small size is probably a different story.
"Duncan Anderson" wrote
in message news:7B7DFF51E6AEFED227E38E77328698E5@in.WebX.maYIadrTaRb...
> There madeby stretchng and compressing the material, like other pressed
> Inv. Flat Pattern doesn't do distortion, only bends etc.
> ps. I'd like to see InvRx do a flat pattern of a Cortina MkIII bonnet.
In general, this is a difficult problem to solve. The best solutions to this
problem seem to come from ball manufacturers. Baseballs only use two pieces
of leather, although the resulting seam is pretty complicated. The ends wrap
around, so it would either take multiple forming operations or some
I have seen tip shapers for pool cues that looks like a hemisphere with a
You could probably get tooling to stamp a shape like that and then trim the
No matter how you make it, you would need tooling to hold the pieces while
they are being soldered. Even so, it would be difficult to get a good seam.
I worked my way through college as a silversmith, and I thought that shapes
like spheres, etc., were available through the wholesale jewelry supply
Autodesk Inventor Workflow Team
"jmartzig" wrote in message
> ha ha - no. i know it sounds pretty funny. but a customer of ours (a
jeweler) is looking for ways to make a piece of jewelery cheaper. a way to
do this (he thinks) would for us to be able to lay out a flat pattern of a
sphere, and have it welded about all seams. i thought i could do it in
halves, but that dog wasn't hunting either. i thought it may be
un-producible in inventor. i could probably get close using regular ol'
autocad, using a that flat pattern of the earth like i mentioned above. -Joe
"Jeff Howard" wrote in message
> See ivCF "Segmented hemisphere".
> "jmartzig" wrote in message
> > has anyone done this? i would expect the pattern to look like one of
> world maps thats all laid out flat. -Joe