Here's my journey of building a Reprap 3d Printer. Took about two weeks to get to the point where I was printing and I am still tweaking things to get good prints but it's working well enough to share :)
What is a 3D Printer? Basically a 3D printer is a device that moves in an X and Y grid and deposits layers of melted plastic on top of each other to build up a 3D Object. Controlling the machine with a computer, some very intricate objects can be "printed". The process works by forcing a plastic filament into a "hot end" that melts the plastic - much like a hot glue gun.
I initially thought of adding a plastic extruder to my existing CNC machine, but it's not as simple as that. You need a way to control the heated end that melts the plastic, and there are things out there to do this, but in the end I was afraid that too much "reinventing the wheel" and I'd never get done. So I decided to build the tried and true first, and then start changing things, or maybe even build another one after I've gotten the first one to work.
With that said, I didn't want to mess around! I bought kits for everything pretty much. I bought the Arduino / RAMPS kit from Ultimachine - it came with the Arduino, RAMPS board, and some hook up wire and even the limit switches. The Arduino is a micro-controller that is the "brains" of the printer, it's basically the interface that makes the motors move and the extruder force the filament into the hot end. The RAMPS board is an Arduino add on board that aids in driving the stepper motors and all the heated stuff.
Next I bought a printed Prusa Mendel kit from EBay. I bought the PLA version, but looking back I think I maybe should have gotten an ABS version. The kit basically gives you all the parts to connect to build the printer, the kit with a hardware kit (below) gives you the structure of the printer.
PLA and ABS are two of the most common plastics that are being printed right now. PLA melts at a lower temperature and is easier to print (I guess) - The problem came when my stepper motors got a little hot and started melting the mounts they were on! - so if you ask me - go with ABS if you are buying a kit. Although I have tuned my motors to work without getting so hot, but it could have been disastrous if I hadn't noticed!
I also ordered a hardware kit that had all of the threaded rods and smooth rods and all the nuts and bolts... Turns out I was shorted a couple bolts and some of the other stuff didn't quite fit, but I probably saved hours in trips to the hardware store :) The hardware kit also came with brass bushings, and the PLA kit came with PLA ones - I didn't like the PLA bushings so I reconfigured them to be "Carriers" for the brass bushings
I lucked out with the stepper motors - I found an eBay auction for a guy selling exactly what I wanted - he was the cheapest price too ($9 each!) - and he was 15 miles away and even delivered them to my office AND refunded my shipping costs! You can't beat that! :) The stepper motors are what make the machine move it it's 3 directions; X and Y, and then Z (up and down)
For the hot end I again turned to eBay - bought one that looked really pro and so far it works great. the hot end is what actually melts the plastic, and also has a "nozzle" on the end that the melted plastic is forced though. This one has a .5mm hole and that's basically the "resolution" that can be printed
Lastly I ordered a heated Bed off of eBay, a heated bed helps when you are printing ABS plastic, without a heated platform to print on the ABS plastic will warp when cooling and ruin your print / object - I don't have that hooked up yet though so I can't say how good it is, but it's very well made.
I *Could* have saved some money by sourcing and scrounging my own hardware and maybe making my own hot end - heck even soldering my own RAMPS and Arduino - but again I probably never would have gotten done.
Below is my pictures in order of the build and a few of the things I've printed so far! and then a video too!
Update 11/17/2011 : I was having some trouble with the extruder - it was, well, not extruding :) so I examined the hobbed bolt I got with the Vitamin kit and discovered that it was pretty crappily made. So I hobbed a bolt on my mill.
Basically to hob a bolt on the mill I put 4 skate bearings on the bolt and then clamped it in my vise on the mill and then loaded a tap into the spindle and put the mill on SLOW... then I drove the spinning tap into the bolt where I wanted it, with the bolt held in the bearings it was allowed to spin and thus a hobbed bolt is created :)
I also had a heck of a time with the plastic timing pulleys - they were either breaking or just plain crap and slipping, etc... so I made myself an aluminum timing pulley - Using Bob Adams Timing Pulley generator and my 4th Axis on my CNC machine, I now have a precision timing pulley! Anyway check out some pictures of the latest look and my pulley and hobbed bolt :)
OH! and I've got the heated bed installed too - sweet :)