Rotational molding, also known as rotomolding, is a molding process for creating many kinds of mostly hollow items. The info is not specific to Classic Cylon Centurions, but SURE can be helpful for them and many, many others projects. Here you'll find various threads with great info from our members for the hobby of costuming.
groupleaderzeta wrote:nice vid showing basic roto-casting
Thank you for that post ....Good job Centurion!!! this vid gets into the mold process which is great!!! the next step is talking about the mold process so this vid is right in there!!!
I just found this one tonight! It looks pretty good!
Not really an article just pics and breif summary of their built machine and a real cool video that takes you from the machine build to making the molds to makeing the parts . They even use one of the Rotocasted parts as a plug to vacuum form another part ( most likely Bubble Packaging of their finished product)! The machine is a project of design students Andrew Duffy, Craig Tyler and Edward Harrison from the University of Rochester for the Creative Arts.
The video is the construction of a minature rotational moulding machine, The making of molds and masters, useing the Rotocast machine, Vacuum Forming parts made from the Rotocast, Making Piggy Banks and Duckies and Custom Designer toys!
This is Andrew Duffy's web site called Studio My First Very cool site and this is where he sells his production design Flat folding Rotocasting Machine. for 300.00 British Pounds which is about $487.00 American
He also sells a CNC Spin Top mould for 200.00 British pounds about $326.00 American
Huttman wrote:Ok first off, thanks for the kudos, and letting me know you were going to post that Second, Rotocasting is an art in itself. You can build a machine in any way you can. Wood, Aluminum, Steel... But the key is, MATH.
Sorry about suprising you with the post but after seeing what you built and your work, I couldn't help my self
I want you to know that I did think about telling you but since you published those links on other threads already, I didn't think is was a big deal. Besides you might have tried to talk me out of it..lol
Seeing your machine inspired me to start this thread!
Being mentored by an expert, That really does qualify you as an expert in my book! your work is awesome your molds are beautiful!
My question to you is, you said the key was the math.....Did you mean the cost vs savings of the machinery?
The molding and casting material cost compared to other methods?
The calculations for the gearing ratio?
The geometry of your design?
The calculations for finding the center mass of your molds? or maybe all of the above? LOL
What should the revolution ratio of the inner frame to the outer frame be? 1:1, 1:2, 2:1, 1:3, 3:1, ???
Does it vary from mold to mold depending on the weight?
Would making a Helmet require a 1,2, 3 or 4 pc. mold?
Huttman wrote:Ok first off, thanks for the kudos, and letting me know you were going to post that Second, Rotocasting is an art in itself. You can build a machine in any way you can. Wood, Aluminum, Steel... But the key is, MATH.
Sorry about suprising you with the post but after seeing what you built and your work, I couldn't help my self
I want you to know that I did think about telling you but since you published those links on other threads already, I didn't think is was a big deal. Besides you might have tried to talk me out of it..lol
No worries man, im just razzing with ya
-At what age should you tell a highway that it is adopted?
The Association of Rotational Molders is an orginization for the trade of rotational casting industry. If you work in this industry this would be the association to belong to.
I thought they would be good to mention here even though it is very unlikely that any of us would join them, as we are not professional Rotocasters and just a bunch of hobby guy's trying to make Cylon suits and laser guns.
However ......after many hours of scouring the internet for information on this subject I have found very little...
Alot of videos of various machines spinning away with god awful background music.....
I did in fact find several examples of Diy rotocast machines and I have posted all of the videos, articles and plans that I could find that were relative.
Books are even harder to find until I came across this site.
The Association of Rotational Molders orginization offers a library of books on the subject at hand. and that brings us to this link.
Although you must be a member of this org. to access their library, they do have a book store loaded with books on this subject.
This is the PDF Order Form for the following Books and Videos
[attachment=0]Publication and Merchandise List 2007.pdf[/attachment]
Books
A World of Applications
The generic design allows you to use this glossy, 4-color
brochure as a marketing tool to promote your company and
the process. (28 pages)
Glossary of Terms
Includes common terms and definitions related to equipment,
molds, quality control, colorants, and additives. (31 pages)
Introductory Guide to Designing Rotationally Molded Plastic Parts
Covers process capabilities and applications. Directed toward
improved product design and quality. Contains useful
formulas used by production personnel and engineers. (25 pages)
Moldmakers' Glossary of Terms
Common terms used in the design and manufacturing of
molds. (30 pages)
Practical Guide to Rotational Moulding by Roy Crawford and Mark Kearns (2003)
Describes the basic aspects of rotational molding and includes
information on the latest state of the art developments in the
industry. Illustrated. (174 pages)
Rotational Molding by Glenn Beall
Written as a guide to the process. The reader will gain a
broader understanding of the process and will be in a better
position to design and develop low cost, high quality plastic
parts. (241 pages)
Here is the link for the web site and they do have downloadable files for this build but it's some sort of cad design program for CNC so if ya want em you'll have to do the ground work.
The first one is a cool variation and I still don't know what advantage it is to vary the speed of the inner chamber. but that one looks pretty cool. A little on the industrial side though.....Looks very pricey
Rotocasting PDF 
So far this is the one of the only written materials I have found on this subject. and it's more of a power point demo than a "How To" book
It looks pretty good! 
The machine is a project of design students Andrew Duffy, Craig Tyler and Edward Harrison from the University of Rochester for the Creative Arts. 
Second, Rotocasting is an art in itself. You can build a machine in any way you can. Wood, Aluminum, Steel... But the key is, MATH.
