Today we are going to talk about 3D printers.
I feel like 3D printing is both the most common of the digital tools, but simultaneously the least understood. Not that there’s anything wrong with it, I love it when we get questions on things… but I feel like the 3D printer questions are often the most out of left field. So it’s about time we covered it!
A 3D Printer is a machine in the class of precise, computer-controlled equipment. The tool head is a nozzle that heats up and has a feed of plastic going into it. It’s basically a tiny little glue gun the melted plastic gets pushed out and can be used to build up shapes from nothing. It’s like magic… but it’s not magic.
3D Printers, have control over the X,Y and Z position of the head as well control of a range of other factors that affect the plastic extrusion process. Like the temperature of the nozzle itself, the temperature of the build plate, the rate at which the plastic is getting pressed through the nozzle, and and the height of each layer of the print.
But what are the parts of a 3D Printer?
To cover the basics let’s start with the gantry, which has motors and a timing belt setup to control the X and Y position of the tool head. The Z direction is usually controlled by something with a finer resolution like a lead screw.
The tool head has a thermocouple heating element and a small motor to feed the plastic into a metal nozzle. The plastic filament is usually stored as a spool kind of like wire, ranging from 1 mm to 5 mm thick.
The gantry is usually on top of a fixed plate where the plastic is deposited. This fixed plate is made of glass or coated metal so it can be easily heated by another heating element and also so that prints are easily dislodged from the smooth surface.
So… What are the types of 3D Printers?
There are a lot types of 3D printers, with many variations.
The type of printer described earlier is called an FDM or fused deposition modeling 3D printer. This means there is a substance that is deposited on a surface by a hot end nozzle, and the subsequent layers are fused together as they harden.
There are also 3D printers that have lasers which selectively cure a liquid resin on the build plate. These are called SLA printers,and they’re quite precise. Their layer height is the thickness of a human hair.
There are also printers that burn a layer of a plastic powder, hardening it into a shape layer by layer. These are called SLS or selective laser sintering printers.
There is also variation in how the 3D printer itself builds: you can have printers that move the hot end along the cartesian axes, or a delta printer which moves the hot end using three co-dependent arms to control the position.
We use Delta printers at Makers Workshop because they tend to work more quickly. But, they do need more vertical space as a tradeoff for that.
There’s also a large variety in what materials 3D printers can print, but thats a Maker 101 topic for another day.
So… What are 3D Printers good for?
The biggest advantage to 3D printers is the wide range of types of shapes they can make. Organic forms in 3D, overhangs, hollow shapes, multiple axes, all types of curves, detailing or text of any size are easily achievable on a 3D printer.
Parts can be easily scaled with 3D printing too, you literally just make it bigger and go for it.
It is also relatively easy to design files for 3D printing as compared to other digital tools like CNC routers and laser cutters. Thingiverse.com is filled to the brim with user submitted designs that are free and ready to print.
You do not need to care about speeds, feeds and paths like the GCODE generating step of CNC routers. You just need to generate a compatible 3D model for your device and then you’re good-to-go.
The other benefit to the 3D printer is that there is no safety hazard to leaving the 3D printer running unmonitored. While the print may fail, it is not inherently unsafe, so oftentimes, you can just start a print and leave to work on other things.
3D Printers do have a few drawbacks, though. You usually have a limited selection of materials with 3D printers, as it is mainly based on availability.
The more interesting materials, like flexibles and resin, tend to be more expensive.
Another consideration is that 3D printing usually takes a lot longer than the other CNC methods. 3D printing parts is often an overnight job. Larger items are often multiple-day jobs. And if the printer gets bumped, there’s no salvaging the print and you have to start over.
Another thing to take a moment to mention are supports. When printing overhangs the software will put in supports so that the print has something to print on top of. It can’t just start printing in thin air. These supports add time to your print, because the printer needs to build them in addition to the finished part. They also need to be removed which adds a step. Removing supports can sometimes be easy, and it can sometimes be a pain.
Because the finished product is almost always plastic, often with build lines from the layers, the finished product can feel a bit chintzy without some time and effort focused on finishing the print.
3D prints tend to handle compressive force really well. However when handling shear or tension they tend to be less durable because they can break between layer lines where two layers have been fused together.
This isn’t really a concern for most applications of 3d prints, but if you were using a 3D printer to make parts that were going to be taking significant wear… it’s important.
Lastly as far as downsides go, for basic shapes like cubes or cylinders and so on… 3D printers are a pretty clumsy way to go. Using a Laser Cutter, CNC Router, or even just hand tools will save you a lot of time, and offer a much wider range of material to choose from than a 3D printer does.
So there you have it! 3D Printers!
There are a lot of subtopics within 3D printing, more so than the other machines we’ve covered so far, that I think we are going to do in future Maker 101s. So be on the lookout for those if you are interested.
Also, let us know in the comments if there are any other topics that you want to see us talk about on a future Maker 101.