I wanted to give a very basic overview of 3D printing and some terminology I throw around like everyone just knows it.
There are a lot of different kinds of 3D printers out there that all print in very different ways. The two most common are FDM and “Resin” which includes SLA/DLP that use photopolymers. While there are a lot of persuasive arguments for using a resin 3D printer for miniatures, I am currently unable to use one because my apartment is small and full of sun (the UV light will solidify any excess resin in the printer) and I can’t use it in the library as the resin puts out noxious, toxic fumes. (This is why we had to move away from printing with ABS plastic, as I’ll get into in a sec.) I’d like to try one in the near future though.
FDM – Fused Deposition Modeling. This is the kind of 3D printer I’ve been using and one of the most common and cheap kinds to buy. FDM works like a glue gun, depositing thin layers of plastic/metal/wood/concrete out of a nozzle, building the 3D object line by line.
Direct Extruder vs Bowden. Direct extruders have a gear located just above the hot end (basically: heater, heatsink) that pulls the filament down to the nozzle. Because the gear is located right above, it can make the hot end heavy and usually requires extra support. For this reason, Direct Extruder 3D printers tend to be square and have limited print areas.
Bowden extruders have the extruder located elsewhere, usually on the side of the machine. The filament is fed from the extruder through a Bowden tube over to the hot end. This allows for the printer to have a more open frame, allowing for bigger print beds. (Technology is improving all the time, so this is changing. There are a lot of people in the 3D printing community trying to improve on FDM design.)
Both kinds have Pros and Cons, so it’s hard to say exactly which is “better.” It depends, really, on what kind of filament you’re using.
Filaments.
In the past, 3D printers used primarily ABS plastic which is a very sturdy plastic (same used by LEGO) but requires an enclosed, heated bed. ABS prints at a high temperature and is a little finicky about sticking to the bed (common issue: curling on the edges) and shrinkage after printing. It’s a good plastic for parts that will be exposed to high temperatures or a lot of wear. ABS sadly puts out a toxic, noxious stench while printing, which is why my library discontinued using it.
Nowadays, the most common FDM printer material is PLA. It’s cheap, it’s biodegradable and compostable, made from organic starches, and does not put out a toxic gas. It prints at a very low temperature, ~200 degrees Celsius, and doesn’t not require a heated bed. The downside is that it’s brittle, melts in hot cars or near windows in the summer, and it’s not water resistant. In my experience, it’s best to test different filaments to find what works best with your machine. Cheap multicolor packs often jam a lot or require slightly higher printing temperatures, so be careful and check the reviews online. One of the coolest PLA filaments is the Wood filament that contains actual wood chips!
Flexible Filament (TPU) is, as it’s name implies, flexible, so once printed, the plastic object can be squished, stretched and manipulated easily (think small squishy plastic toys). Due to its elasticity, you have to use a Direct Extruder FDM printer and, with my experience with it, you have to carefully hand-feed the filament into the machine as it prints because it’s stretchy and often jams. My advice when using this filament is that you stick to small, easy and hollow prints and babysit the machine (or use a volunteer) while it prints.
PETG is a plastic similar to what you find in water bottles. It’s a very cool-looking filament, often transparent, and like ABS, it works well for printed parts that will be exposed to high temperatures. For instance, if you need to 3D print a fan case to go around the hot end of another 3D printer and you don’t want it to melt, then PETG would be a good option. The biggest downside of PETG is that, for me, it is beyond the most difficult and finicky material to print with. I’ve tried printing it in an ABS printer, I’ve tried my Monoprice, and I’ve about torn my hair out trying to get it to work. You need a heated bed and you need to fight with the material. It jams fast, it overheats and underheats, and it’s just a pain to work with. Good luck!
The Basic Parts of a FDM 3D Printer
X,Y,Z Axis. This is assuming you’re using the most common Cartesian FDM 3D printer and not the Delta, which has more than three axes. Basically, this is just simple geometry. Z goes up, x and y go side to side and back to front. Each machine may handle this differently. The Flashforge Finder raises and lowers the bed (z-axis) while the hot end slides around on the y- and x-axis. The Ender 3, on the other hand, moves the bed on the y-axis while the hot end moves on the x- and z-axis. The biggest reason why you should know this on your machine is when something goes wrong and you want to look up the problem; for instance, I had a layer-shift issue on my Ender 3 Pro where the print would randomly shift a millimeter. When I realized it was a problem with the y-axis (the bed of the machine) I discovered it was a problem with the jerk setting on the printer due to the heavy, new glass bed.
Hot End and Extruder. These are the meat and potatoes of the printer. This is where everything will go right or wrong. As mentioned before, the extruder is the gear set up that pushes the filament gently into the hot end. The hot end is, as its name implies, the hot part. This is where the magic happens; filament is melted and pushed through the nozzle onto the bed. The term “hot end” includes the heat sink, heat break, nozzle, heater block/cartridge, wires, and tubing. You don’t really need to know everything that goes into it unless you plan on upgrading or building a 3D printer from scratch. The most important bits are knowing how to fix the hot end when you have a jam. My advice? Look up your printer online and follow a guide. Some printers are more difficult than others.
Bed. This is where the plastic is printed onto. Online, you will read a lot of arguments back and forth on good and bad beds and what you need or don’t need. In my experience, heated beds are a little better than unheated (but not essential and with a little tape/glue you can get anything to stick), and glass beds are definitely nicer than crappy, flimsy magnetic beds. Some plastic beds, I’ve found, aren’t as magical as some reviewers make them out to be and they degrade over time.
Mainboard. This is the “mother board” of the 3D printer. The Flashforge and the Dremel Ideabuilder have massive mainboards to support their more complicated user interface and touch screen. The Ender 3, Tevo Tornado, and Monoprice all have tiny little arduino-sized mainboards tucked away in a separate part of the machine. The only reasons you should even see your mainboard is if you have replace/upgrade it (as I did with my first Ender 3), or if you are replacing a fan and you want to plug it in yourself instead of soldering/clipping the wires together outside of the mainboard. As with building a computer, always do your research on what plug goes into where before you mess with the mainboard.
Spoolholder. Not all printers come with one of these, as I discovered with the Tevo Tornado. Always look at reviews online about a printer’s spoolholder and whether or not you need to print one yourself. It can really mess up a print and cause issues if your spoolholder is not in a good location, getting caught up on itself, or putting a lot of stress on the extruder.
Card Reader/PC hookup. Another thing to check before you buy. How does it read the gcodes? Does it have an SD card reader? MicroSD? USB? Make sure YOU have a converter for these kinds of cards. You can also buy an external converter (I insist, in fact, if you use the Ender 3) and 3D print a case for it to attach to the machine. In my experience, only a few of my machines successfully connected to a PC, so I wouldn’t waste time trying to get it to work. Just save the sliced file onto the SD card/USB and use that. I have been fiddling around here and there with setting up an Octoprint with a Raspberry Pi and I’ll get back to ya’ll on that when I get it to work.
The Slicer Programs/File Types
When you 3D print, you can’t just go online, find a 3D object, save it to a USB and plug it into a cheap 3D printer and expect it to work. No. You have to “slice” the object first.
A slicer program is an application that will take a 3D object and cut it into layers so that the 3D printer will recognize what path to take to create the object. It’s actually pretty simple. You take your found 3D object, usually an STL file, and you upload it into your printer’s preferred slicer program (Cura is a free one that covers many printers). You then add supports if you need them and the program will slice the object and convert the file to a gcode that the printer will recognize. You have to be CAREFUL that your settings are for the correct printer! If you save a gcode for an Ender 3 and print it on a Flashforge Finder you can potentially break the machine. Each gcode is tailored to a specific printer.
I could go on forever about slicer settings and all that, but it’s very printer specific and it’s best you do your own research into what might be needed for you machine/issue.
