I'm new to Arduino, did some of the sample projects then combined two of them to display messages on the LCD based on temperature changes, it was great fun. My ultimate goal is to create funky interactive objects with LCD display and inputs, may be ultimately some kind of interactive robot once I get to that level of skill.
I think if you want to know about 3D printing you're going to have to ask a company that provides that type of service. There are a few companies that can print stuff for you.
As far as boxes... Since you're working with custom designed products, you're probably not going to find something that exactly fits your needs. You're probably going to have to get a generic box, and modify it yourself. You can drill holes in them, and cut openings with handheld tools.
Big subject, 3 d printing by the additive method ( as used by maker bots) is a very versatile means of creating varied shapes.
Most makerbots use pla plastic , this deforms and shrinks at the temperature of a cup of tea.
Professional companies generally use abs.
Abs printed this way is about 60 percent as strong as moulded, it is also porous.
Makerbots can print with abs but for the likes of enclosures dimensional errors and distortion is a problem.
Some makerbots have heated beds which ameliorates but does not solve the problem in the z direction in particular.
Also depending on your enclosure you may need a second head for support material, all of mine have needed this so far.
Most 3D printers can print ABS, you just need a heated bed. You can add that to any printer, but a good starting printer is a creality3D, it has all the basics from the gate, is reasonably well engineered, and costs are 300 usd.
3D printing is time consuming though, especially for a beginner. You got to learn 3D modeling as well to get the most of your printer.
While FDM printers can produce good quality parts, I’d suggest using an sls printing service once your design is finalized, because the finish and durablility is a lot better.