Opportunity to blow my own horn (eww gross)
You can get hard edges and semi-sharp corners in rotomolding. One of the issues to design for is the nature of ‘poly-warpalene’ isn’t going to stay where you want it, unless some rib geometry is included. Roto is most often used for big/dumb/tough products because of the low cost of tooling and nearly indestructible nature of the material. You can do operations like undercuts though if you calculate the shrinkage rate; the ribs on these coolers are undercuts but shrink-out of the tool. Made with pride in the USA by IRP. You see these on the sidelines of NFL and some NCAA football games. Think ‘Yeti’ but sharper lines and cost-no-object features.
I’ve never seen small rotomolded products - as in smaller than a shoebox - but there’s no real reason why small roto products can’t be done, its just that there are better ways to do small things like injection blow molding.
