Rotational Molding Questions?

[Barry1492]

I'm looking into rotational molding as a design option for a composite container. I don't have any experience with this and was wondering if someone could point me to a good link or offer some pros & cons about the process.

Thanx -Barry

 

[swall]

I'm not sure the process is conducive to molding composite structures.The process is such that the molding resin tumbles between the inner and outer mold cavities as the mold assembly rotates. As no pressure is applied, the process is dependent on gravity and inertial forces to completely fill the cavity.Reinforcing fibers, strands or preforms would tend to impede the uniform filling of the mold, I would think.I've seen small boats molded this way from high density polyethylene, no reinforcement. I saw this at a place in Durham, NC (it might even have been called Rotomold, but don't hold me to that).

 

[Barry1492]

Thanks......it doesn't necessarily have to be composite. I looked into it myself a bit. We already have a composite container designed out of E-Glass using VARTM. It needs to be load bearing....like up to 2000lbs.....my instincts are telling me that it is unlikely to be able to do this with rotational molding....at least not without using significantly more material.

 

[MadMango]

All the Little Tikes yard toys are made from this process. Reaching 2klb load bearing might be a problem, depends on what wal thickness you can live with, and the ability to design reinforcements into the structure.

[green]"I think there is a world market for maybe five computers."[/green]
Thomas Watson, chairman of IBM, 1943.
Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[TVP]

Rotational Molding is not a suitable replacement for glass-reinforced composites produced by VARTM. RM is essentially used for HDPE and maybe PP-- no glass fiber.

 

[MikeHalloran]

Conjecturally speaking, you could rotationally mold a liner/ mandrel for a filament wound or other FRP container.



Mike Halloran
Pembroke Pines, FL, USA

 

[jdarco]

Check out

http://www.rotomolding.org

This is the rotomolders association, you may find some information there, or at least some molders to talk to.