Question since you have formlabs what process do you use to clean your print models ? And how many days until you change your alcohol?
We don't run Form printers, but we do use several Form Wash units for our two-step wash process, and we're very happy with them. They're a good mid-range wash unit in-between the entry-level "tupperware and a shaker table" / $150 hobbyist wash unit tier, and the thousands-of-dollars high-capacity extra-fancy commercial offerings. They're well-constructed and durable, and they lift prints out of the wash bin to dry once the timer runs down, which is very good for speeding your post-processing along and making sure you don't forget parts in the wash, which'll ruin more sensitive materials like nightguard/denture tooth resins. We've been running two for 16 hours a day for a year and have never had an issue, and we've added two more (two first-stage, two second-stage washes) to accommodate large numbers of parts coming off our big build plates.
RE: alcohol changing, we change it every day- the clean wash becomes the dirty wash, and the dirty wash gets poured into a drum for recycling. We're pretty high-volume, and we recycle our alcohol in-house with a still, so this isn't a problem, but most users won't have to change the alcohol out nearly so often. We also run the Wash half-full of solvent and not at the fill line they recommend, which makes it saturate with resin much faster. Smaller labs could probably get by for at least a week on a single fill before moving it down the line or discarding it, and they supply a hydrometer so you can measure the resin saturation and know when to change it. That said, if the second wash isn't very clean it'll still leave some resin residue on the washed parts, so I often wash parts briefly with brand-new alcohol as a mini "third wash" before drying them to deal with this final residue to get a really clean part.
