Way back when, I guess I could have used a CNC milling machine to make up the little deli cup water dishes I was using to put into deli cups with the baby corn snakes.
A friend of mine made up a little jig to clamp and hold six of the PVC end caps I was using to cut grooves into them in one pass on my manual milling machine. I bought that mill specifically for this purpose. At least I had a motorized traverse table on the thing. I wound up selling a bunch of those water dishes and that actually paid for the machine. I bought the PVC endcaps in bulk, which wound up costing about 14 cents each, and was selling the finished water dishes for $1 a pop. I'm not sure I really broke even if I take my time and labor into consideration, however.
But unless I had someway to automatically feed the raw end caps into a CNC mill, I guess it would still be a mostly time consuming manual process.