Weekly Challenge Group

This one was tough for me to figure out. Took 6 different attempts. Should have watched the video first.

Inventor. 4 features.

A one off part would probably be best done as a casting. 3D print a plug, sand cast, then hand clean-up.

Production would be CNC machined in two setups. Start with a rectangular block held in a standard vice with the long sides vertical. Machine about 70% of it with a ball end mill producing one of the pointed ends vertical. Then invert, hold with custom machined soft jaws, machine the 30% remainder with the same tool. Locating the part accurately in each setup is very important in order to seamlessly match up the two machining operations.

Good idea to use a second circular array, I like it!

When casting, there will always be sprues, and if I want to get the correct geometry, I have to mill one way or another.

Milling is a good idea. I would take a round billet instead of a square one - there will be less metal consumption in chips. And clamp it into a regular three-jaw chuck, there are also six edges in the central section and a top.

Thanks for your reply!

There is no drawing method that fully meets the requirements

Try to make drawings with your model and you will see extra lines.

The requirements are: "Like other sphericons , with cross section edges number that has an odd factor, while rolling on a plane, its maximum height remains constant."

The model starts with a simple revolution of a triangle to form a cone shape. Using surfaces would be the most difficult method. It really is easy to produce with any CAD system once you understand the geometry.

Watch the video in the original post.

After reading your method, I realized that it is so simple and learned something new, thank you

i never heard of this shape before (and thought the title was misspelled). Thanks for introducing me to this simple 3D shape,

After watching the video, I made a Tetracon just for fun:

Very easy to do in solids - should be just as easy with surfaces.

This challenge has turned me into a "polycon addict". Here's one of the polycon shapes I came up with. I used the same steps as in the video, but with a different shape instead of the side of a polygon.

of a polygon:

Little different version. I might have to actually print this one to see if it works

This is very interesting. Do you have a name for this model/shape? Can you show me the first revolve sketch?

Edit:

I think I figured it out. Dimensions aren't correct but I think the base form is right.

Edit 2:

with a few tweaks, I think I got it. Printable too. I will print it tonight and check. Thanks for the idea.

Sorry for the spam. I am kind of obsessed with this shape/technique. Did a one with 8 side. Possibly we can make a parametric model and have fun. :D

I can't claim credit. I originally saw the idea on this guys video, but I ended up creating mine from scratch after learning how to rotate these things. https://www.youtube.com/watch?v=wb29-ULRBaE

I will try to remember to post my sketch with dimensions tonight when I get home.

cool video

IS THIS, OK? IS IT ACCORDING TO THE CHALLENGE

Drunken race: tetra, hexa and octa...

...it is true that they are fun when they run!

SolidWorks Motion

PS: I don't know if it's a very fair race... but I forced all three so that they have the same weight and their polygons fit into a circle of identical size. However, it is expected that they advance at different speeds for an interesting reason to observe and analyze.

I think I got it