Industrial 3D Printers.
There are various ways to classified 3D printers for industrial usage.
By Materials, we have FDM printers, which are focus in general prototype printings, and these printers are most commonly available, due to its costings, and related Filament (PLA, ABS, HIPS, etc).
Weakness is their printing quality and printing speed. But generally speaking, the type of printers are able to meet most of the common printing needs: product prototypes, review designs, testing fittings, architecture designs, etc.
While for some high requirements printing needs, such as electronic parts, dental models, these printings are either very small, or engineers need to assemble printed objects tightly to testing out CAD designs (such as a laptop with all the parts printed). For these printing needs, SLA (Stereolithography) printers are recommended, and they normally work with various types of Photosensitive Resin.
Generally speaking, SLA printers cost more, especially for large printing size (larger than 20CM). And printed objects need post printing processing to clean the chemicals, remove the supporting structures, and post-curing the prints with UV light. SLA printers are able to meet the requirements for most high precision engineering designs for testing and checking.