Know your Components: Cold Extruder - 2.1

Alright, so this is your stock cold extruder. You can see that we have here our idler bearing. We have a hobbed bolt. This is actually a toothed gear and in between these two, the filament is gripped and fed through right like that. Okay, so this spring is a tensioner spring. When you pull on the lever, it moves the idler bearing away from the hobbed gear, which allows the filament to flow freely in between there. When you release pressure and the spring is tense, it pushes this into this, so it clamps down on that filament and that's what allows it to push it through or retract it back. The stock extruder on the Ender 3 will eventually have some problems for you, so I will show you the main problem now. That is this. It is plastic in there, so the part where you screw the screw down is brass, but if you screw it too tight, you'll crack this plastic plate. Now, mine looks really dirty because I didn't have an extra extruder on hand when I broke this and I was kind of upset, so what I did was I superglued it, let it dry, put it back together, screwed it back on, and it held long enough for me to print another one. So this is a backup that I have never actually used because the superglue actually held so long that it stayed until my new extruder arrived, so I didn't actually have to put this one on. I do recommend printing a backup arm while your arm is still good, simply because it'll be easier to replace while you wait for replacement than trying to superglue it like I did. I think I just got lucky because there's quite a bit of tension on there and it's easy to break. Also, over-tightening that, over-tightening the bolt that goes through the idler bearing is what causes this to break. Now, that idler bearing is supposed to move freely, so you don't want it too tight, and tightening it down is what basically causes it to break. The other thing I wanted to show you is if you look in here, my filament guide in the arm, there's some wear, there's some extra filament laying there, and you can actually even see on the top of this guide that the filament has begun to wear through there. So yes, you are going to need a better extruder eventually. You might want to upgrade to the aluminum like a lot of people do. The only problem with that is instead of that plastic rubbing off of here, it'll start rubbing off of your filament, and you do get a little bit of dusting. So as you see here, this is a CH Power. This is the replacement extruder that I put on. It's quite dirty right now from all of the filament that gets ground through that little spot, and if you're not lined up, that can actually cause inaccuracies. So if you're grinding that much filament off, that's how much filament is missing from your model. So we're going to have to take care of this and fix it. We'll be doing that in one of the next videos as well to ensure that we get proper flow through here without leaving particulates. But I wanted to show you one more cold extruder real quick. Now this one is a super cheap cold extruder. It is entirely plastic. It's not going to last very long. The gears in there that are in contact with the filament itself are actually metal, but the rest of this, it's just a cheap model. You can see the idler bearing back there on the lever right there, and then the hobbed wheel, which is run by this tiny little motor, which as you can see, is half the size of our regular NEMA 17. So I haven't gotten the chance to turn this on and try it yet. I don't know how well it functions. It's on this other printer that I'm building, and I have a lot of, as you can see, wiring work to do before we get any further on that. So now that you've seen three different extruders, you kind of know what we're looking at. So again, the main difference here is, to be technical, the extruder is all one piece. So the hot end and the cold end extruder are technically both parts of what is referred to as the extruder. But in the 3D printing world, when we speak 3D printing terms, when we say extruder, we are talking about the cold extruder. The other part is called the hot end. It's referred to as the hot end. Now the hot end does actually create the extrusion. It heats the plastic and extrudes it and deposits it. So it is technically a part of the extruder assembly. The reason it's important to differentiate between the two is because if you're having some trouble and your cold extruder isn't working properly, and you just tell people it's your extruder, or you mistake it with the hot end, they're not going to be able to give you the right fix or diagnosis to correct your problem. So there you have it. That's the extruder, the cold extruder to be specific. And pretty soon we're going to get into how to change this guy out, as well as a few other mods that we're going to be doing. Coming up next is going to be Luke's hot end fix. That will do a lot to your hot end that will allow you to not worry about jams nearly as much, not worry about the Bowden tube getting stuck, not worry about a lot of problems that can happen to your hot end. So we are going to take care of the hot end first, and then we will move on to changing and adjusting the extruder to eliminate that filament grindage. And like I said, in the meantime, if you don't have an extra extruder laying around, definitely go on Thingiverse. You can grab this lever. I don't have the model number on hand. I printed this quite a while ago, guys, but it's an easy search. And in fact, at this point, it'd probably do you some good to go on there and just search Ender 3 mods, Ender 3 upgrades, and Ender 3 stock parts, because you can never have too many models for fixing things that might go wrong with your printer. But I can almost guarantee at some point, if you don't change the extruder, that lever is going to go. So if you want to stay printing until your new extruder comes, having one of these laying around will be extremely handy.