Hello need a recommendation for buying a 3D printer with build size, at least 8" x 8 " x 12" with great quality that does not show layers on a curved surface, minimum warping and up to $30,000.
Your requirements are curious. Most people would like to have a printer that does NOT show layers on a curved surface and to have zero warping. With a budget of thirty thousand dollars, you have quite a range of choices, most of which are outside of this hobbyist forum, in my opinion. You would be well advised to seek commercial/industrial sales representatives, but again, that’s only my opinion.
I hope you’ll post the final result of your quest.
It was a typo… Not showing layers 
Yes consulting also commercial reps, but always good to see if others have recommendations
@David_Sherwood I would say plastic based materials, metals are a plus but not a must. Basic colors. Quality of prints. Need prototypes that come out not needing any Sanding or painting to be shown in Tradeshows as almost the real thing. Consumer product prototypes, mostly enclosures. No need to very strong mechanical properties, more about accuracy and finishing.
@Ashley_Webster thanks for your suggestion, build size seems too small.
@GloberDesign1 This may not be what you are looking for but I’ll throw it out there. I use printers under 2K with a 12 x 16 x 10 build volume and dual heads that can print as thin as 0.05mm layers (not super fast at that resolution) for producing smooth curved/domed surfaces. Typically I use 0.4, 0.3, and 0.2mm nozzles. I get highly accurate prints off of them holding to less than 0.1mm of tolerance. I routinely print PLA parts that cover 5" x 9" flat areas with no warping at all. It will print anything that does not require more than 250 C.
By your mention of no painting are you looking for a full color printer like an Objet or would two color (FDM) or single color (FDM, SLA/DLP) do if painting of the surface was not required? Are you looking for something with injection mold surface finish?
In that price bracket, SLA or powder bed. They’ll both give you really good print quality. Powder can also do coloured prints, but you have to clean the powder up. Alternatively, SLA printers print marginally stronger prints than powder, but the resin for them is often expensive and a pain to take care of (you can’t expose your printer to direct light while there’s resin in the reservoir or else it’ll harden).
8x8x12 is stretching it as far as DLP goes. It’s my understanding that it too, suffers from warping when you’re talking about large prints. The biggest thing I can suggest is do NOT get a machine that’s 8x8x12 if you’re going to be printing 8x8x12 objects. Always get a machine that is 20% larger or more. You do not want to be getting into the very edges of your build volumes all the time.
@Jeff_Parish that sounds cool, do you build them yourself? I have a need only for one color print. Yes looking for something with injection molding finish.
@GloberDesign1 I build all my own printers (I have 4) but they can be purchased assembled.
Concerning the finish I think you will be hard pressed to find something like that right off a printer bed. You will likely need a two step print/finish process. As was mentioned before there is a limit to how fine a layer you can get with any FDM process so you can always detect lines on a curved surface even with a high resolution SLA. This becomes more apparent as the part surface angle approaches orientations more parallel to the printing plane. Then there is the direction of the slope to consider. For example printing a sphere with matching surfaces top and bottom will have layers more visible on the bottom (negative slope - overhangs) as opposed to layers on the top (positive slope - self supported) even when they are very fine.
Everything in your budget constraints I’m aware of requires some cleanup (support removal) and/or a surface smoothing process. CLIP is the only technology I know of that might do it continuously enough to avoid visible lines but you won’t get a Carbon CLIP machine for $30K and the two step curing process and resin toxicity are something to contend with. But again as was mentioned before I would seriously consider getting at least two printers which makes that option even more remote.
With that said there might be a fairly inexpensive, (compared to $30K), process available to give you what you want. It is something I’ve had my eye on and I’m considering it myself.
It could use an FDM printer similar to what most of us on these forums are using but use a proprietary PLA-ish type filament and a post process vapor smoothing machine.
Disclaimer: I have not used this filament so I can’t make any statement as to the accuracy possible printing with it or to its consistency and stability. I also have not used the vapor smoothing machine, it might not fit a part as big as you have in mind, and I do not know how much the part dimensions are affected by the smoothing process. Given what you have described you are looking for in a finish this is the printer/post process combination that came to my mind.
The technology is in the tail end of Kickstarter mode and they do not seem to be shipping yet but it might be worth investigating. Others here on the forum may be backers and can provide additional information.