How are these made...

[Ger21]

Based on a pic I see in this auction, they're particle board, not MDF.
Wall Decor Shelf Shelves MDF Interior House Room Cube Round Shelf Hidden Bolt | eBay

It would appear that they are molded into that shape from the factory. There's no possibly way to make that from flat sheets and still make any money on it. Even for those working for $2/day.

[John McNamara]

They are only 20cm deep. I suspect they may be a simple vacuum forming, made from a heated sheet with vacuum over a former, then foam filled to give rigidity. A common process in industry.

https://www.google.com.au/?gfe_rd=ct...vacuum+forming

Regards
John

[paulus.v]

Nice question Jas! Molded into that shape and laminated with plastic? Impossible to get a smooth finish by molding. The particle board has a core layer made of larger particles and a surface layer made of smaller ones.