Feb. 4, 2016
Between the names of the parts and their functions, it can be hard to keep it all straight. Here is a quick guide of the anatomy of a 3D printer. We will focus on mechanical and electrical components of the most common desktop 3D printer type: fused filament fabrication (FFF) or fused deposition modeling (FDM).
The print bed is the surface that your objects are printed on to. Typically it will consist of a sheet of glass, a heating element, and some kind of surface on top to help the plastic stick.
Most print beds are heated in order to prevent the object from warping while it is being printed. Due to thermal contraction, the plastic will shrink slightly as it cools. This causes the object to warp upwards around the edges and peel off the bed. Heated beds keep the bottom of the object warm, in order to prevent this.
See also; Enclosure, Bed Surfaces. Some printers do not have heated beds. This limits them to printing a narrow range of materials including mainly PLA (the material that is least prone to warping) and sometimes PET.
The bed surface helps the plastic stick to the bed during printing but also allows it to be removed easily when printing is done. There are many different kinds of bed surfaces. Most printers will come with some kind of all purpose surface, like BuildTak or PEI film. However, for best results you will want to use different surfaces depending on the material you are printing. Use this guide for print bed recommendations based on the material.
Many printers have some kind of a system for automatically making sure that the bed is level with the nozzle. Some do not, though, and must be calibrated by hand. MatterControl also has the ability to compensate for unlevel print beds with software. For more information, see our expanded article here.
On direct drive printers, the hot end and cold end are connected together, one on top of the other. The filament goes straight down through the cold end and into the hot end.
This gear bites the filament and pushes it down through the hot end
The idler is a spring loaded wheel that pushes the filament up against the hobbed gear. Most printers have a way to adjust the tension on the idler, so that it neither squeezes the filament too hard or too little.
By not using any plastic insulators in their construction, all metal hot ends are able to reach much higher temperatures and print a wider range of materials. However, they require active cooling.
The end stops are how the printer knows where it is. They are little switches that get pushed whenever an axis moves to the end. This is how the printer finds it’s starting point before printing. Most printers use mechanical switches, but some are known to use optical sensors.
These are usually used on the printer’s Z axis. They rotate, thus forcing nuts to move up and down. Inexpensive printers will use simple threaded steel rods, which are essentially extra long bolts. Higher quality printers have smooth chrome plated leadscrews designed to minimize backlash.
Belts move things. The X and Y motors have sprockets that drive the belts. Most printers also have some way of adjusting the tension on the belts.
Unlike regular DC motors, which rotate continuously when given power, stepper motors rotate in increments. This gives them precise control over their position. Most printers use NEMA 17 type motors with 200 increments (steps) per revolution.
This takes the 120V AC electricity from the wall and converts it to low voltage DC power for your printer to use
ATX Power Supplies- These are the same power supplies used in desktop computers. They have been repurposed for use in many printers. They are very beefy and efficient, and have separate lines that provide power at a variety of voltage (12V, 5V, 3.3V).
Voltage - some machines run 12 volt systems, while others run 24 volt systems. This becomes critical if you are going to replace components - especially your heater cartridge or hotend. Make sure you order the appropriate parts.
Some printers also have an SD card slot from which they can load G-Code files. This allows them to run independently without a computer.
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