At the heart of a DLP printer, the projector is the most important part of any DLP based SLA printer.
A DLP projector produces UV light by way of a Mercury vapour bulb. Different manufacturers have tweaked their bulbs for different purposes. Either good service life or high lumen output. This will moderately affect the cure time of each layer.
The most crucial factor, where LED projectors suffer, is the UV spectrum emitted and its intensity. DLP projectors all produce a very wide spectrum of UV light, allowing them to cure cheaper/less sensitive resins than their LED cousins.
Along with the UV intensity each projector can produce, the throw distance (focal length) of different lenses, means some projectors optics might need to be adjusted post purchase, to focus at short distances, relative to your specific printer setup.
In the same breath, almost any DLP projector will produce enough UV light, within the correct spectrum to cure Photo-sensitive resins. Provided you are patient, smart and brave enough to make the adaptions/changes to your projector, required for your printer to work.
A lot of DLP printers you can buy, include a projector in the box, whilst some printer manufacturers let you decide which projector is best for your needs/budget yourself.
Luckily with the LittleRP, I didn’t have to meet any of these requirements, as Brad Hill the owner and developer of the LittleRP, has done all the hard work for us and put a short list of pre-approved projectors on his website, that he has painstakingly figured out all the little settings for, to get them to work with the LittleRP machine