I’m not talking about folding, cutting, or taping. I’m talking about somewhere between pulping, molding, additives, papier-mâché, low strength composites, and IKEA furniture.
I’m wondering how cardboard egg cartons are formed or any number of other logistics packing materials. That process must be relatively cheap to do and might have a lower environmental impact compared to many other materials. I have a collection of various cardboard and discarded rough card stock I use for custom boxes, storage, and jigs, but it would be cool to make 3d printed molds filled with a pulp like slurry of old cardboard to make stuff for the cost of time and trash.
My wild guess on how they do that industrially is macerated pulp in water and a big nasty press to squeeze the water back out. Maybe some really cheap adhesive goes in there too, I don’t know.
For arbitrary molding, you need a certain level of fluidity that will be hard to achieve with a fairly pure pulp. You’ll notice all those packaging materials - or at least the ones I can think of - are shaped to be suitable for stamping. However, it can be used as reinforcement in concrete or a resin!