How Do They Do It?

That I can deal with. How do they form the holes? Is the material flexible enough to just pull out of the mold? I'd think it might hang up on the mold features that form the holes. Remember where ever there is air, there was metal in the mold.

If (or, since) the ball is formed in 2 halves, then there are no 'holes' per se. The mold that makes half of the ball has an outer hemisphere into which the channels are cut, and an inner mating hemisphere with no channels. The goo is injected and it sets up. Once the two halves of the mold are parted, the half-ball, which is very flexible, peals out of the larger, outer half of the mold.

I'll have to look at the ball again, the next time I visit my friend with the dog ball.

I'll report my findings.

You may well be right, although it didn't seem that straight forward when we were drinking beer and trying to figure out how it was made.

"there was metal in the mold."

I think that might be an assumption. There are other ways like mould things, Silicone like you said, or centrifugal casting.. (but you know all those)

also, perhaps the thing wasn't moulded in the final shape, but finally assembly pulls it into final shape?

interesting question.

Chris

Pentagon punches can be made movable backward.tough task to handle so many punches but theoretically possible.

I'm voting this answer GA, even though I feel I'm due for another pondering session over the weekend just to confirm it.

We'll resolve this issue "pre-beers".

Cheers guys.

Thanks. Let me (well, all of us) know if you reach a different conclusion.

Cool .gif of the smiley heads & beer, by the way.

One more thing, I'd expect that same "witness/parting/glue" line to be on the inside as well if it is molded in half and then joined. Is it?

My entire thought process was hinged (incorrectly, I now surmise) on the idea that it was a one piece molding and that was the external parting line.

I may have to sacrifice my buddies dog ball and cut it open to look for the glue line.

Maybe Sparky the pit bull will bite your butt when you chop apart his Buckyball for analysis, but then sometimes you just have to sacrifice yourself for scientific knowledge! Make sure to show us the pictures!

Yep the same as a tennis ball - only a part line nightmare. UB has it right s'pose I'd better go vote.

Possibly it was roto cast.. great for hollow structures..

Excellent thought - GA

Would explain the smooth interior and presumed absence of flash - [as it hasn't been mentioned]

Don't think so. The inside is too well finished.

Nah, its just like a single cell organism that evolved into a multicellular structure. I guess. Or could be the mold is made out of sand. Lol

Soccer mom! Soccer mom! Bail us out here! How do they do it?

I think Usbport had the right idea, but a more "equatorial" line might have been chosen.

BTW, the shape is a truncated icosahedron.

I'm looking right at the dog toy and that's how the line looks. Here's a photo with the seam marked by arrows. Tracing along one side of the seam I see hex, hex, penta; hex, hex, penta; hex, hex, penta. The mating surface has the same pattern; it's symmetric, allowing a single mold-set to produce both halves of the sphere, though it could be done with many molds in mass production.

The inside of the ball is very smooth, which is why I said the inner mating surface is a (smooth) hemisphere.

Exactly. This line more closely divides the shape into hemispheres.

Same line.

Photo oriented 90° to the picture above and turned so that the zig-zag 'equator' is slightly more 'normal' to the viewer. But the same line.

Maybe they took this fungus and recreated it by watching it grow from ....??

3D Printing?

Looking at the one I borrowed from my dog for a few moments... As mentioned, there is no inner, only an outer seam-line but there is also what looks to be "hand-trimmed" knife cuts around every hole on the inner suface which is not nearly so smooth as the obviously machined molding appearance of the outer surface. It's possible that there would be two hemispherical moulds, brought together, with an inflatable ball placed in the middle and inflated so as to make the inner surface of the mold. After the injected rubber hardens, the spheres are separated, the ball deflated and extracted through one of the holes and then a lot of necessary trimming by hand is done to ready it for market.

It is called a collapsible mold.

The inner is inflatable, the outer is two halves injected.

Actually there maybe other ways, but this one would be I think, the simplest.

Wangito.

That I can deal with. How do they form the holes? Is the material flexible enough to just pull out of the mold? I'd think it might hang up on the mold features that form the holes. Remember where ever there is air, there was metal in the mold. bellows in india |Expansion joints in chennai

is it possible the inner part of the mold is a rubber/silicone ball fill with air.

Already mentioned. I don't think so, if it is really injection molded. Hydraulic pressure is rather high inside the mold during filling. I think it would collapse the bladder.

But, what do I know? I'm going to have to find the supplier and ask how it's made.

I'll let you know.

hi lyn: i have built centrufugal molds and if i had to make this object depending on what it was to be made of and if it is a mix and pour sort of stuff like silicone or polyurethane foam or many of the other mix and inject or pour materials available today - i would make an outer mold only that has on its inside surface the blockouts that form the holes in the object. it would be made in two halves with part lines like has been suggested here and it would be set up in a two or three axis frame that can spin it at anywhere from 25 to 200 rpm that has spheroidally oriented motion to evenly distribute the pour into the mold until it solidifies - then the mold which might be made of something flexible that is contained in an outer shell of something rigid so the soft mold separates from the cast object easily is bolted and unbolted as quick as possible.

One of the idea that may be suitable for thermosetting plastics is making two halves that includes those pentagon profiles, an inflatable rubber ball is dropped in one of the half and then die is closed with other half,Low temperature thermosetting plastics (liquid form) injected in the mould from small hole and left to cure.After curing process rubber ball can be removed just by leaking its air.

The inflatable ball on the interior can be brought up to any pressure, just not exceeding the busting strength of the two strong hemispherical molds. The rubber could be laid in even before molding, the ball positioned/inserted, molds brought together, excess squirts out, heat applied, rubber sets, moulds separated, product easily pulls out, and inner ball deflated and removed being pulled through one of the Hex holes, then the trimming of the minor leakages by hand on every hole where there was not a perfect seal to tidy things up. This was a good topic/question, BTW, but humbly I ask, how a "Good Answer" can be given to an incorrect conjecture? :)

Could be a gas assisted injection process. Pretty cool stuff.

Some links with info below.

http://www.bauercomp.com/en/products-solutions/plastics-technology-0

http://www.ecommercialplastics.com/processes.htm

http://www.ecommercialplastics.com/GasAssist.doc

interesting technology...

chris

How about the "lost ice" method - the insert into the mold is an ice cube or piece of frozen water with all the "outies" where the final "innies" are - mold a low pressure foam around it - particularly a thermoset, open the mold, allow the ice to melt away and viola!

Just our two cents

Jim Wilson

Centrifuge or spin molded.

I have seen similar using the roto cast method. Great for hollow parts and the hex can be either eliminated with the mold or trimed out later as they will be either very thin or just a partial casting.