this is a quick question for the experts here. I understand that the FDM technology generally uses two materials - one is the modeling material and the other is the support material. Therefore many times the products produced require some sort of postprocessing in order to either polish the product or remove the support material (e.g. By dissolving it in a liquid bath)
is that the case with Lulzbot 3-D printers as well? could you please tell me what kind of postprocessing is generally required and also if there are certain cases where postprocessing is not required at all?
With a TAZ in stock form, there is only one nozzle that deposits one material. When there are large overhangs, slic3r will generate code for support material to be printed in the same material as the model if instructed, but arranged so that it is easy to remove from the part by hand or with pliers. With a dual extruder (files available on devel.lulzbot.com and released soon, probably) slic3r can be instructed to print one material for the model, one for the support. With PVA as the support, the post-processing involves leaving it in water to dissolve away the support (kind of like http://vimeo.com/75748504 (complete with sweet electronic backtrack)).
There are many cases where post processing is not required. The printed parts that make up the printer require little to no post processing, for example. It mostly depends on how many and how big the overhangs in the model are.