3D printing via paper sheet stacks was one of the first 'rapid prototype' technologies. It was around in the automative industry at least in the mid 1980's, an

3D printing via paper sheet stacks was one of the first 'rapid prototype' technologies. It was around in the automative industry at least in the mid 1980's, and was called LOM - Laminated Object Manufacturing. The machine I saw would unroll glue-backed paper onto a plate, laser-cut the layer into it along with laser cutting a consistent grid pattern everywhere outside the part. Then repeat for all the layers. This took forever (literally days for a big part) but when it was done you would get this giant block that felt like essentially a glue-up wood countertop. You would then bust away all the cube pieces on the outside, revealing the 3D part inside. The part would have this grid line pattern on it from where the waste cube cuts intersected the final part. You could then varnish the part and you'd have a pretty much rock solid, heavy reproduction straight from a computer model. I know that these were used for vac-forming parts straight off them, and also as patterns for sand castings. It was interesting as this tech has been pretty much erased, it's even hard to find pictures of it these days. Anyway. I don't ever recall ever seeing one that printed color onto the paper however, but I'm sure this was something that was experimented with. Here is a 1991 paper describing the tech, which had already been around for a few years by then I think: https://repositories.lib.utexas.edu/server/api/core/bitstreams/95bf7a6d-8ea9-4a47-bc81-4a3dd320a8e4/content https://repositories.lib.utexas.edu/server/api/core/bitstrea...