I’ve been supervising a VFlash for 4 months now, and when the cartridge is new and you print during the daytime, the parts are beautiful. However, ambient temperature and humidity really mess with your models. Because the speed is 1/4" per hour in the Z direction no matter how large or small your part is, an average model can take 12-15 hours, and of course, the temperature and humidity can fluctuate during that time (unless you have a temperature controlled clean room, but then why is this marketed as a “desktop” printer?). When that happens, horizontals bend, and layers separate. Then the layers fall on to the film which extends to coat resin on the build platform (because the part is built hanging upside down). The shredded bits of hardened resin then retract into the cartridge, sticking to your film which prevents the light from getting through the film to cure the liquid resin, and you start getting voids in your model.
The cartridge has an RFID chip which identifies it, and the machine updates the RFID chip with how much resin it believes has been used by the model regardless of actual resin used - so if you wind up with voids in the model due to shredded bits covering the film and preventing the light from hardening new resin, then you literally lose that resin that would have printed in the voids. At about $9 per cu in, that can hurt. Since it’s natural to want to work on your model all day, then let the VFlash run all night so you have a part when you arrive the next morning, you have to be careful that the building does not shut down AC/heat so that the temperature does not change much overnight.
The first cartridges we got in January had welded tops, so you couldn’t retrieve the shredded bits and you basically lost use of the whole cartridge, but then they switched to removable tops so you can clean out the shredded bits. Also, after the cartridge has been in use for a while, somehow resin always winds up on the opposite side to where it’s supposed to be, and gets all over the glass that houses the UV “flash” which cures the liquid resin. This can also affect the build quality because the light needs to get through all that junk. If I put a new cart in and run a small part, it comes out perfectly, and I do mean, perfectly. By part 3 or 4, however, the glass gets gooped up and subsequent models have problems. I’m always cleaning the back side of the plastic film because small hardened bits and streaks of uncured resin seem to find their way back there. I believe it’s due to the path of the film which drops into a small chamber within the cart, and bits of the gooey resin and shredded bits fall in there as well, and the “clean” side of the film gets contaminated. When the sales guy set up the system, he gave us a putty knife because that’s what you have to use on the glass (and sometimes the film - very gently) after every model to get hardened and non-hardened resin off.
The safety mechanisms are weak, and you can open the front door to check on the model, but the UV light may be on when you do it. I wish they put in a UV safe viewing window, because you are supposed to check the model at intervals. They put a window in their easy-bake oven (which cures the washed parts), so why not the printer itself?
Their tech support is excellent. I can’t say enough good stuff about their support guys. Smart, efficient, nice guys in the U.S. who just want to get you going. My only issues thus far have been with the cartridges (and one problem due to older firmware), and the parts washer stopped working (I have yet to call them on that one).
Speaking of the parts washer, the fact that the VFlash is marketed as a “Desktop” 3D printer is a bit disingenuous. It may be the smallest 3D printer out there, but it is larger than a minifridge, and weights 145 pounds. Then, you have to have a slightly smaller parts washer which contains naptha in a lidless open vat (classified as an irritant, so don’t inhale deeply when you mount your part and make sure you wear latex gloves) plus a vat of water to wash the irritant off, and a UV oven to bake the whole thing (about the footprint of a small laser printer). My whole setup is sitting on two 5’ tables side by side, and barely has enough room for the keyboard and monitor to run the thing. Not really something you want in your small carpeted office, but works fine in our fab lab with tile floors and lots of ventilation. Technically, it is sitting on a desk, but…
The resin cartridges have 1.8KG of material, and we seem to make parts that are in the 200-300g range. At almost $0.50 per gram (assuming you can eke out 100% of the resin in it which we have almost done once out of 8 cartridges so far), our parts get a bit pricey.
I have a ZCorp 310+ as well, which is cheap and fast, but the parts don’t have great resolution. When the moon and stars align properly, the VFlash’s printed parts really look great, but the 310+ is way less headache than the VFlash. I obviously have a love/hate relationship with mine.