Quick spot-check to see how up on your production methods you guys are: How was this Ohlala watering can (don't hit the link yet), designed by Barcelona-based CrousCalogero Design Studio, manufactured?
Hints: Yes, the object is completely hollow, as you'd expect for a watering can; it's an older production method (not RP); it's made from plastic, we're guessing polypropylene; and yes, the object is all one piece.
Hit the jump for the answer.Rotational molding! I'd practically forgotten this technique even existed; we see it so rarely, probably because you could accurately describe it as being "expensive, and takes freaking forever."
Our first article on rotational molding is from Core77's early years, way back in 1994. (There's one typo/word missing in the article, see if you can find it.) Pre-3D printing this was the way to make hollow plastic parts. But here's the question: For those of you with direct experience with RP machines, do you think rotomolding will eventually be replaced by 3D printing, and if so, how quickly?
It's true that 3D printing probably takes the same amount of time or longer than it would to spin up the Ohlala, and the "resolution" isn't currently comparable, but do you think the RP writing is on the wall?
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Rapid Prototyping is good for just that... Rapid Prototyping... lets not get too carried away here people... I guess I could see some people try to RP injection molded parts in lower volumes since so many people want to injection mold parts or components, but very few (USA-side) ever put their money where their mouth is because of the tooling costs....Rotomolding Tools don't have that issue... I don't think the DoD is going to start Rapid Prototyping Military Bunkers and Bomb Trays.... I really doubt any Nuke Waste Tanks ever get Rapid Prototyped.... or better yet... Could you see a Rabbi asking for the Kosher certifications on the Rapid Prototyping machine?? If your a rotomolder and your afraid of the RP machine effecting your business... you should have been worried years ago when Rotomolders started closing their doors like K Mart stores.... Some people need to realize that it wasn't technology that drove the Rotomolding industry down from the 500 and some odd molders in North America... it was the poor business practices, lack of innovations and the wh*res of the industry running jobs below costs "just to cover overheads" (I die laughing as hard as possible mentally every time I hear one of you guys say that too btw...) You see how many of those guys are still in business?
What use would a SLS watering can be anyway? It would suck up half of the water!!
- Large sealed volumes, i.e. many objects used in the marine industry.
- Large fluid transport flasks for assorted lubricants, detergents, mixing chemicals.
The rising cost of energy is the probably the only threat to rotational molding as heating the large tool conveyors is rather ineffecient.
The company that produced it is - as other commenters have said - busy as ever. Especially big hollow structures (e.g. junction boxes for telecoms, garden chairs etc.) are ideal to produce this way.
3D-printing / RP? You must be kidding. Most of the products that are ideal to be rotomoulded don't even fit in "mammoth" SLS-machines.
I would have expected a more informed article here. And no reaction from the writer?
I see most of my grieves have been discussed above. But still here's my summary:
+ Rotomolding is not on its way out. It is still the best production technique for many applications and products.
+ Ever handeled a 3D-printed part. It's brittle and coarse. Sure the technique gets better and cheaper each day but we are a far way from having 3d-printed parts with the strength and surface quality of a injection-molded part.
+If you had that water can printed it'll probaly cost you about over 1000$. So no competion to roto-moulding.
+ And yep I would also blow-mould the can instead of using rotomoulding
+ If you want to write an article about 3D printing i suggest you mention this: http://www.technologyreview.com/energy/37540/
Rotomoulding is one of the quickest, cheapest and easiest ways to make large plastic objects.
Im not sure how you nearly forgot about it, our potential clients ask about it all the time.
http://www.sintex-plastics.com/build&con/build_constru_usp.htm
Cheers
RP materials and processes are improving, but this is a question that should be posed to people with knowledge of roto-molding and other processes, as well.
RP is not a silver bullet, despite what seems like an ID fascination with having a one-size-fits-all answer to manufacturing.
As for surface finish, there are RP machines(polyjet) that do pretty high resolution(.0006" layer thickness). With texture built into the build file, maybe surface finish will eventually not be an issue of "can we make it this way?" "Should we make it this way?" will remain though.
A more fundamental limitation comes into play. RP methods require high precision movements of the RP machine for every part. Roto-molding, like injection molding, blow molding, etc. requires high precision to build the tool, then much lower precision to build the parts.
Newer production techniques like 3D printing give us different options to choose in solving problems (and even in selecting which problems we try to solve). But there are aesthetic, functional, and perceptual goals that are still best met by hand-forming clay to produce ceramics-- one of the oldest production techniques in existence.
There are basically these three problems:
-Surface finish
-Durability
-Size
I see all three of these issues individually being overcome in a short timespan 3-8yrs however getting all three in one RP part is going to be extremely hard to do and I see that happing 10-20yrs. out. Hopefully by then the cost of additive manufacturing (RP) will have caught up with our needs.
If you are going to produce more than 10 of that watering can, you'd be better off rotationally molding it than printing it. You'd also get far superior finish, a WORKING prototype, vast material selection, ect.
Sure, anything is possible. But the printers it would make that possible would need to have resolution high enough to define surface texture (microscopic), be fast enough to produce the part in less time than the roto molding (~40 minutes), be able to handle ultra large format 50'x50'x50' (in the case of producing grain silos), be able to print thermosets and a variety of other thermoplastics, and be cost effective. I do not believe that in my lifetime rotomolding would be replaced by 3D printing - And honestly why would you want to.