All 3d printers have a basically the same components:
- Hot end: This is a tube, which plastic filament is forced through. At the end of the tube is a tiny nozel (usually 0.4mm - 0.5mm). There is a heating element which is caused by an electrical short (connect a wire between two terminals on a battery and it will get really hot... enough to melt plastic). The best hotends do not clog, are reliable, are all metal, and can go up to 300C+.
- Extruder: This is the part which forces the plastic into the hot end. This part has 2 main components. rollers (normally notched for grip), and a stepper motor to spin the rollers. You can buy these or 3d print them. The best extruders are bowden style.
- The bed: The bed must always be flat, and level. If it is not, your prints will have many problems. It is critical that your prints adhere when they start. There are a few strategies for this. My opinion is that the best beds have a high current PCB heated plate under glass. You should be able to heat the bed to 130C so you can work with any material without warping. If the bed is not heated, you can run into a lot of problems with warping
- The frame: Everything connects to the frame, therefore it needs to be sturdy. If the frame cant hold 200 pounds of weight sitting on it, its not sturdy enough. If the frame can wobble you will have a poor print quality.
- The power supply: For a good heated bed youll need at least 150W @ 12V.
- Control board: The cheapest is the brainwave, and the best is the aztec. Search around... youll find them. printrbot board is decent as well.
- There are many styles of 3d printers. Cartesian, delta, and other. Cartesians are the most common. Deltas are difficult to fine tune, but are wicked fast.
The main things which make a printer good is a sturdy frame, a carriage which has only a hot end (more weight moving around quickly = more momentum, and more backlash). Don't cheap out on the steppers. They will overheat, and start making noise, and eventually fail. You want a printer which will be able to do 10 hour prints. A hot end which can handle up to 400C can print in almost any material. In general all you really need is ABS. Speed and quality are the key measurable metrics in a 3d printer. If you want the best printer I would recommend you buy a rostock kit, or make a variant. Be prepared to spend a full day calibrating and fine tuning.
