So let's take a look at the hardware of a 3D printer. Now, 3D printers are just a mixture of electrical components alongside some gears, guide rods, and bolts. They all work together to print plastic. So I'm going to show you each part in a little bit of detail. We'll start off with the part of the printer that we've been talking about, which is the part that manages the filament extrusion. Before we proceed, let's just be clear, extrusion refers to when we're pushing the filament out of the nozzle at a higher temperature. The tool head manages that, and that's this part here. We're going to jump here and take a look at some pictures that we've taken, some clearer images of what the go is with a tool head. One of the first things that you'll see when you look at your tool head is the big block stepper motor that's hanging out of the side of it. This is actually a NEMA 17 stepper motor, and this is a tool head from LulzBot, if you were wondering. Every tool head is going to have a stepper motor, and that's the part that uses very precise electrical steps, like a stepper motor does, to produce the extrusion movement.

Now essentially what you've got is that stepper motor with 200 steps per revolution is attached to a tiny gear, which is attached to a bigger gear on the base of your tool head, which we can see there. That gear actually has a countersunk bolt that goes straight through the centre of the tool head all the way to the front. If we go back to that picture, you can see the bolt coming out here, and we'll take a look at that bolt. You can see there, the bolt goes all the way through the tool head. There's a bearing here, another bearing here. Down the centre of it, this is the important part of that bolt, it's actually called a hobbed bolt. It's called a hobbed bolt because it's got a notch driven out of it here, and then inside of that notch are small tiny teeth. Those tiny teeth grab onto your filament, they're pushed against with the other bearing, so this bearing is on a hinge here, pushes up, it's free to spin, and it will spin the opposite direction to this hobbed bolt, and it will feed the extruder, the filament down into the extruder, down into your tool head, which we'll take a look at here.

You can't really see it in the original image, which was this one, so this is the tool head here, and it's hidden by this cooling fan, and that cooling fan actually attaches to the heat sink behind it, and these two fans are actually for part cooling, so they'll actually cool the part that you're printing. This front one is purely for the heat sink on the front of the extruder. This is the hot end, now this is an all-metal hot end, and it has four main sections. The heat sink is obviously for dispersing thermal energy that's produced by the heater cartridge on your hot end. In between, we have a heat break, and that's purely just to give some room for the heat to disperse before it hits the heat sink. The main point that we're trying to get across with this whole design, or the designers of the extruder are trying to get across I should say, is you can't have heat traveling up your tool head, otherwise you'll get blockages in your filament, and that's because the filament will actually start melting at a point up here, there might be some notches and grooves in here that the filament will get caught on, and if you don't have a nice clean run all the way down into your heater cartridge to fill up the well that is the nozzle, you won't be able to actually get a consistent extrusion, you'll just get blockages in your hot end, and it will require you to pretty much replace your hot end, or maybe drill out your nozzle, or something horrible like that.

So yeah, we've got the heat sink and the heat break, they're good for cooling your filament, the heater cartridge is there to heat your filament up to its extrusion temperature, and the nozzle is essentially the pen tip, it's a tiny little hole in the end of your nozzle, and this one's made of brass, the one that we can see on this printer here is made of brass, and it's got a tiny hole of about 0.3 to 0.5, 0.6, they're all different sizes, different shapes, this is a hexagon-sized nozzle that we're looking at, and it's a 0.5-millimeter nozzle, so that refers to the width of the extrusion of your plastic, so if you were to extrude one line of plastic, it would be 0.5 millimetres wide because of the nozzle. Next, we're going to take a look at our print bed, now as we're using an additive manufacturing process, our first layer of plastic has to be as flat as possible, and also print the bed as best as possible. To assist in that process, the 3D printer community, the creators, everyone has worked together to produce some hardware options that make your prints stick better to the bed.

So we'll take a look at a diagram here, so firstly, you'd be hard-pressed to find a printer without a heated bed, now essentially if you maintain hotter temperatures to the print as you're printing it, you'll minimize the opportunity for the plastic to shrink, and maybe pop off the bed for example, or even just warp up away from the bed which will cause problems in upper layers as it's essentially shifted from a flat model to now a curved model. By maintaining that hotter temperature, we can completely avoid that. So what we've seen is a lot of printers including that in their design, so we can see this diagram here, we've got a heating element on the base side of our heated bed, now we've got the heating element attached to some borosilicate glass, and then finally on top, a polyethyramide sheet. That's a basic diagram of some printer's heated beds, that's not always the case, but we'll take a look at this borosilicate glass and what that means. Borosilicate glass is just a really strong glass that's the perfect material for the repetitive expansion and contraction of a heated bed.

Essentially it's the stuff that you would see in a chemistry lab used for beakers and all that sort of stuff. It can withstand really fast, rapid changes in temperature, which is just what we want when we're pushing our heated bed in the space of five minutes, it could go from room temperature up to 110-degrees. So that's why we chose to use borosilicate glass and now it's sort of the standard with all 3D printers, you really want that borosilicate glass bed, it's quite a high-quality bed to have. Now, printing directly on the glass comes with its positives and negatives I suppose. Some filaments just won't do it, other filaments require some painter's tape or some glue or something. So we have seen the advent of this, now this is polyethyramide or you might hear it called ultram or PEI and essentially it's just like a plastic glass layer that goes above your borosilicate glass layer, so you've got your heating element away from everything that heats up the glass and then above the glass you've got your PEI.

When you were using glue and painter's tape and stuff, sometimes you'd have issues and you could either not have your print stick to the printer or you would have the problem where it would stick too well to it and by trying to remove it you could actually damage your bed. There's some horror story pictures out there of people smashing their glass beds, quite expensive, it's not what you want to do. So someone somewhere came up with the idea to use a plastic covering of your bed and eventually we got two polyethyramide PEI sheets to cover your bed and essentially it works to cling to the print as it's printing and then as you finish your print, the printer will lower the temperature to the perfect temperature to remove the print off the bed and you've got a very safe way of removing prints and keeping them held down to your bed. Now, PEI isn't a universal thing by any means, there's still filaments that require you to put down a little bit of maybe PVA glue or something, but for the most part it's really good and the filaments that do require a little bit of glue work really well with the PEI so it's pretty much one of the best things that we see.

Finally, we can have a look at our print bed. Now, I'm going to use the image here of my LulzBot Mini and I just want to talk about bed leveling. So like we said, there were two important parts of our print. Now, it has to be a flat, even first layer and it has to stick to the bed. Now, to get a flat first layer, we need to level our bed and in the older printers, maybe still in some of the newer printers that haven't included this technology, you would have to essentially get your nozzle right up close to the bed, level it, see that it's level, maybe put some paper in between there and just get it as flat as possible, as close to the bed as possible and that would be your starting layer. But, there's been some technology inventions and we've decided to use automatic bed leveling. So, on this bed you can see that there are four metal pads on each corner, one metal pad on each corner of the print bed. What the printer does is it uses essentially an electrical charge put to the hot end, so all the way through that all-metal hot end and at the start of every print, your printer will go to the back, it'll rub its nose, so it'll go down and it'll rub itself on this foam pad at the back here and clean itself off. Then it'll lift up, head over to this first pad and go through the process of leveling itself.

Once it's stepped down, it'll step down really quick, once it touches it'll know that it's made contact because these are the ground points essentially, it knows it's made contact, it'll go back up a little bit and then take like a lot smaller steps, right down and once it touches it'll know because it's conductive and then bounce back up and it knows that that's the zero point essentially and then we can set an offset of that amount so you can see that it's not quite flat with that bed, set the offset amount and the printer will always know exactly where zero is when it begins to print your first layer. So that's a really cool invention in the world of print beds and that's why that whole process is very important. We've got the heating element to keep it nice and warm, we've got the borosilicate glass so we don't have to worry about our print bed cracking or getting damaged, it's a very strong glass. Finally, we've got the PEI which helps cling to the print and then obviously that auto bed leveling is a great invention. So that's pretty much covering the print bed.

So let's take a look at the motion control system of a 3D printer and that refers to how the printer is going to maneuver the extruder and the print bed around the working space to build up your model. Now this printer, our example printer today is actually an example of a Cartesian printer so we'll take a look at the diagram of what that means. So that means that our printer has movement in these three axes so that would be your Y axis, your X axis and your Z axis. There's also a different type of printer that we see, we don't have an example printer here but this is essentially a diagram of it and it's called a Delta printer so it's using like a triangulation calculation to keep that tool head flat, the tool head would be down here and all the motors at the top here using angles and a little bit different, definitely a little bit different but it still works just the same. Now what you can see with Delta printers is they can actually be very, very fine in the centre but as they move toward the outside of the print they would become less accurate so to speak. Also with Delta printers they use a cylindrical build volume so with a Cartesian printer you've got a rectangular build volume so that's length, width, height and they're the three measurements that you would use to define your build volume but with a cylindrical print volume you would just be using like the diameter of the bed and the height and it would obviously be constrained in that way.

So that's the difference between the two main types of printers that we see especially with FDM printing and the next part would be the frame so that's an extremely important part of the printer because its rigidity dictates the precision of your printer. So originally we saw threaded rods used as frames for printers but it LED to all sorts of issues in the frame losing its rigidity as the printer would be moving and all the motors would be jerking around. So a step up in reliability became aluminum extrusions and they're long straight aluminum bars with like a T-nut extrusion all the way through and you could use T-nuts to hold all the components to the frame. There was also some laser-cut plywood and acrylic designs and they were really good but eventually we're seeing a lot more people use sort of water-cut aluminum cases like the Lulzbot here. So the aluminum is obviously the best, it's one of the most rigid metals, it's really good, you can form all sorts of shapes with it. So people are using either these folded really solid aluminum cases for their printers or they're using the aluminum T-nut extrusions and then they can print their own sort of hinges and right-angled joints that will really firmly hold that in.

So that's the idea behind your frame being strong, there's been a bit of an evolution over time and it's, yeah, it's a really important part of your printer. So don't overlook your frame, it can always you know sneak up and bite you if something's wrong with it. And finally, we'll take a look at the control board. So that's the brains of your 3D printer, the controller board that's sort of housed in this side of our printer here. Now there are dozens and dozens of types of control boards but the main thing that they're required to do is drive the stepper motors that the printer uses. Now RAMPS is one of the really popular brands or names that we see for a printer controller board and it stands for RepRap Arduino Mega Pololu Shield and so it's a shield that gives you, your Arduino Mega, all the stepper drivers that it needs to run a RepRap 3D printer. So that's you know a homemade DIY style 3D printer. There's also other types of boards that we see so Rambo's one and they're all based around the same idea, it's just giving a microcontroller or a computer the capability to drive motors and maybe handle the processing of the software required to do so.

So that's pretty much the idea behind a 3D printer, there's a few obviously finer points that we could have gone over but now you know that this is the tool head, it manages extrusion, you know how that works, this is our print bed, you know why that's working the way it's working, we've got our controller box, we've got our frame and we know that this is a Cartesian printer and we know how to tell the difference between Cartesian and Delta. So remember with this printer in particular, our stepper motors are the things that are driving all our axes not just the tool head. We've actually got two here for our Z axis, we've got one up here for our X axis and one down the bottom here at the back for our bed to move backwards and forwards. So what we're going to do now is take a look at 3D model software and G-code so we'll take a look at how we can turn our model into some G-code for our printer to print with.