You can use a factory to manufacture crates of identical items from a Manufacturing Schematic. These items may be for sale or to be used to create other items; some schematics require items created in the same factory run (identical serial numbers). A common mistake is to make a schematic with one resource you have on hand, and then try to run it through the factory with another resource. They have to be exactly the same, down to the specific name. The same applies for subcomponents; the serial numbers must be exactly the same.
When making a schematic, you usually need to using a specific crafting tool and be standing next to a crafting station (or your crafting droid) in order to get the "make manufacturing schematic" option. Choosing this option lets you choose the name of all the items made in the factory run and also lets you set the manufacturing size limit. The limit is from 1-1000. There is almost no reason to limit the manufacturing size unless you are paranoid about burning through scarce resources and you think you'll forget to limit the amount of resources in the input hopper. Experienced crafters (and those with resources to burn) will wait for amazing experimentation results to make a schematic. If you choose the "make manufacturing schem" option, a schem will appear in your datapad. If you click on the schem it will list all the ingredients, subcomponents and their serial number. This is the schem that will go into a factory and work for you.
Operating a Factory Edit
Operating a factory is not complex. You must be near a factory, although you can be riding your speederbike. The radial menu has several different options, similar to a harvester. One option is "access schematic". This gives you the option to use or remove a schematic. After choosing use schematic, a list of the available schematics that this factory can use will pop up. If there is already a schematic in the factory, when you place a new one in, the schematic in the factory will pop back into your datapad. If you have completed the factory run (as in reached the manufacturing limit of the schematic that was in the factory), then the schematic will simply disappear when done. If you are the owner of a factory, you will get an email when this happens.
The results of your factory run will appear in the output hopper in crates. Different items have different crate counts. A high complexity schematic set to 1000 units can take several days to complete. For this reason, busy crafters may be running multiple factories at once.