[music] Hey, everybody! I’m Tom Telus. This is the tomb of 3d printed. Horrors and today we’re gonna talk about under extrusion now. This is something we all experience at some point. It’s not just when you go to. Taco Bell too often anytime you’re printing with an FD M 3d printer. You run the risk of having under extrusion. The thing that’s really frustrating about this is if you ask 10 people, what’s going on, you’re gonna get 10 different answers, and the reason is there’s more than 10 causes for it. So what we’re gonna do is walk through each one step by step, so hopefully you can better understand what’s going on and troubleshoot any issues with your 3d printer. Let’s start with how to identify under Extrusion. What does it look like well? In most cases under extrusion is going to look like this, It’s gonna have missing plastic in the sides of the model. You’re gonna have gaps in layers. Those are the areas where the plastic did not extrude properly for one of a host of reasons And you just have a gap now under extrusion can also present itself as a brittle model. Maybe there’s no gaps at all in it. But due to the under extrusion, the individual layers did not properly bond together and you can literally pry the model apart with your bare hands layer by layer. Both of those are under extrusion, the most common issue or common cause of under extrusion on a 3d printer is temperature. You’re printing too fast for the temperature. You’re melting your plastic at, and it can’t fully melt in time to extrude so it has under extrusion. How do you fix it? Well, two things one you can up your temperature 2 you can decrease your print speed or you can have a combination of the two now. This is critical. When you up your temperature, only do it. In 5 degree increments, you can very rapidly go from under extrusion caused by too low of a temperature to under extrusion caused by too high of a temperature, What’s. The difference well at too low of a temperature. The Met plastic is not fully melting, so it can’t go through the nozzle. Therefore, nothing comes out and you have under extrusion when you have too high of a temperature, you get heat creep going up the length of the hot end into the areas that should be cool the plastic, where it should be solid starts to deform its reached its glass transition temperature and it bulges that causes drag and it can’t be pushed cleanly through the system, resulting in less filament coming out and under extrusion so again. If you’re adjusting your temperature go in five degree increments, it’ll make it much easier to identify that sweet spot a lot of times. You have a roll that printed great for a while, and then it starts having under extrusion. What’s going on? Is that roll has absorbed moisture that’s affecting the temperature at which it will effectively melt, so it’s very common to have to raise the temperature, five or ten degrees by the end of the roll. If you’ve had it for a while than what you started out printing ass, so just be aware of that. Watch out for your temperatures and speeds now, almost as common is simply the film, snagging up before it feeds into the system. If you’ve taken your filament on and off of your printer a few times and you’ve let that end flap up into the spool, it’s very easy for the end to get under another wind of the filament and it snags, so you always want to tape that loose end of the filament to the edge of the roll or one of the side little holes, you can snake it through, so it doesn’t work under the other filament loops. If it has, you’re gonna have to untangle it because it’s just going to keep tangling up every few turns and causing binding and drag and under extrusion for you, so that’s a very common cause of under extrusion for you on these printers now on down towards the extruder. If you have any kind of filament guides, make sure the filament is feeding cleanly through them. If they’re not, that could be a snag and that could be holding you up Specifically on the Kree ality under three, the filament guide on the extruder, where the little lever is that you squeeze on the spring that is made of plastic and in just a matter of weeks or even a month or two. The hole in that plastic can wear from being a hole to being more of a triangle shape than that filament rubbing through it, and it erodes down. It will start snagging and causing under extrusion on you that so. I recommend in Mike Reality Three build video, replacing that out with an aluminum extruder. I have that linked in the product description or in the video description here for this video, but it’s just four screws. You can change it out in about five minutes, and it’s really worth doing. You’re gonna have to do it at some point with the under three because that plastic lever will not last very long so snagging is another common issue, just look for places along that filament path that it could be hanging up another cause of under extrusion that people overlook very easily. Is the slicer. Sometimes you can get the wrong. Filament diameter listed in the slicer for slicing your models. This just happened recently. With Kira, 3.5 in cure a 3.5 The under three profile had the filament diameter set to 2.75 millimeter when, in fact, uses 1.75 millimetre filament, this caused the slicer to think for every millimeter, a filament that was being pushed into the system. Almost a third more filament was actually being gone through than what was which resulted in under extrusion. So make sure your slicer filament settings the diameter. You have set matches the diameter filament yet. Your printer actually uses again. It’s really easy to overlook this, and you can get really frustrated looking for a mechanical issue when, in fact, it’s a software issue next bed leveling. If you try to print your first layer too thin. In other words, your nozzle is too close to the bed, The amount of filament that’s supposed to be coming out can’t, and it starts backing up, and that creates a partial clog. It will heat creep will go up the length of the filament and it will swell and that will cause drag. So check your first layer. Check the skirt that printed around it. If that skirt doesn’t feel like fishing line, if it feels completely flat, you’re too close to the bed. You need to real evil, and that will resolve your extrusion issue. Now, filament feed gear on your extruder that gear with this teeth that grips the filament if that clogs if it gets a lot of plastic shavings in it, it can no longer grip the filament for feeding through the system and that can also result in under extrusion now related to this. If that’s clogged, It’s a good bet that you have plastic shavings in your. Bowden tube as well. If you have a Bowden tube feed system. So you can clean the filament gear first. Take your filament out of the system. Clean the filament gear with an old toothbrush. If it looks like you have plastic shavings down in your Bowden tube if it’s a Bowden Tube system and not a direct system, what you can do is simply take the Bowden tube out of your printer and use some compressed air to blow any shavings out, and that should resolve it for me. Bowden Tube is so cheap, it’s only about a buck for the length necessary, Unlike an under three, I would just put a fresh one on and be done with it. But if you want to try cleaning it, you can’t just use compressed air and that should work now, also on the extruder gear. Most printers have an adjustable spring tension for that feed gear. If you have too loose of tension on it, it’s not going to grip that filament tightly enough to feed through your system. What you have to do is there will be a small screw or screws that will actually tighten down or loosen on that spring to add more spring tension on those feed wheels. Check that, make sure it’s gripping tight enough. And if not, you can adjust it now. Unfortunately, if you’ve got like an ender 3 or a. Cr 10 You can’t do that. It’s not adjustable. The spring is always at full force. If that still isn’t enough, what you can do is Shim it. You can put small washers or Shim stock in here between the extruder and the spring, which will compress that spring more and put more tension on the feed wheels. It’s a really easy fix. Just get some washers that will fit over that. Screw, take it out, but the washer’s on and put your screw back in, and that’s all you need to do. Just get a few thin washers and put them on one at a time until you get good, good, reliable extrusion. You don’t want to put too much tension on it because that’s going to make the feeder gear, dig too tightly into the filament, and that’s gonna grind it down, especially on retractions, which we’re going to talk about next now if you have under extrusion in an area of your model that is highly detailed and has a whole bunch of retractions. It could be you have your retraction number set. Hi, now! Remember your feeder gear When it were tracks, it’s pulling that filament back and forth over that gear every time that gear contacts that filament it’s grinding it down some, it’s digging into it. So the longer the length of retraction, the more times that feeder gear is going to pass over any given point of that filament during the retraction process. If you have a whole bunch of retractions in a one area of your model that can grind that filament down to the point, it can no longer reliably grab it. So how do you fix this? Well, there’s two issues here. In both cases, what you’re wanting to do is reduce grinding on the filament. The first way you do, that is adjust your tension on the feed gear. You want it tight enough that it can properly grip the filament to feed it reliably, but not too tight to where it’s actually grinding it down and creating a gap. So you’ve got to find that sweet spot. If it’s too tight, it’s gonna grind that filament down and cause under extrusion. If it’s too loose, it’s not gonna grip the filament tight enough to feed it and you’re gonna have under extrusion again, so you’ve got to find that sweet spot where it’s just barely making an indentation in the side of the plastic, but not too deep of one, and this is something you’re just gonna have to develop a feel for it. Basically, what you want to be able to do is on sections of filament that have already run through the extruder. Run your finger along them. You should be able to feel the dig in the side of the filament from the feeder gear, but it shouldn’t be too deep and again it’s something you’re just gonna have to play around with now. The other thing you can do to help alleviate. This is reduce the length of your retractions. Having a retraction, That’s like eight or nine millimeters is way Too much for me on an Ender. Three my retractions are usually set around Five millimeters. Six millimeters wouldn’t be bad, but anything beyond that is going to start because of the usual amounts where you you start having in detail models, lots of retractions in a certain area you’re gonna be going over the same length of filament again and again and again and wearing it down, so try to get that retraction length down as low as you can without inducing stringing, but you really don’t want it much over six now. This next one is more particular to the Cree Ality series of printers, the Enders and the CR Tens on these printers. The Bowden Tube goes all the way through the heat sink through the heat block or through the heat break into the heat block that Bowden tube then meets up with the back of your nozzle. Now they should fit tight so that your filament goes straight from the Bowden tube into the nozzle. What happens with these printers is? Cree Ality uses a very poor quality connector that locks the Bowden tube into the hot end. Is this a little screw piece? There are about 50 Cents online. I’ve got them linked in this video to put a better one on in my under three build video. I actually recommend that. So the first thing you do is replace those pneumatic couplers for the Bowden tube. The ones that come from Cree allottee are crap. They will fail sometimes in a matter of just a few weeks. They’re gonna fail. What does that mean? Well, when that clip fails when the teeth start breaking off, your Bowden Tube is going to separate when you have a retraction, it’s gonna get yanked up with that filament away from the nozzle that creates a gap that gap is going to get filled with softened molten plastic when that happens that plastic that fills that void is going to start causing drag on the filament that’s feeding through the system and that causes your under extrusion. It will also create issues with your retractions, making them less defective too, and result in more stringing so as I mentioned earlier if you’re singing Inc. Seeing increased stringing on your model and under extrusion? The problem is, your Bowden Tube has separated from your nozzle and what you’re gonna have to do is take the felt. Heat it up. Take the filament out. Take the Bowden tube out. Take your nozzle off, clean all that out and then reassemble it. I have a nozzle changing video on this channel that I’ll walk you through the whole process. It’s not hard, but we’ve already covered it to there, so I’m not going to go through the process here, but that’s your problem. You have to clean out that molten plastic, a really easy way to do that is when you get it all apart while it’s heated, you can just stick a toothpick down there. It won’t harm the aluminum on the inside, but it’s enough to pick off the plastic and get it cleaned out to reassemble, okay. This is for under three owners and some of the other core ality printers that use the same high-end. The factory that assembled these ha ends made a mistake. They left the two alignment. Screws shown here on the left and right on each side of the heat break in when they assembled the unit. These screws were meant to be taken out. When the hot end was done and the printer was assembled, they weren’t, and they even applied the insulation over the heater block over the screw heads. You can’t back them out without having to remove that insulation. So what do you do? Should you remove these well? I have several under threes and I have not removed mine because I’ve not seen any issues with under extrusion. If I ever do, I will take them out at that point, but for me, it’s a case of if it’s not broken, don’t fix it now. If you are having issues with under extrusion, it could be from this. What’s happening is heat from the heat block is transferring up those screws into the heat sink. That’s the part in red with the individual fins for cooling when that area heats up, it’s meant to be room temperature when it heats up, it can cause the filament inside of it to reach its glass transition point and soften slightly as you do retractions. It’s going to stretch that filament out when it pushes it back in, it’s going to deform it. That is gonna cause additional drag, which can cause under extrusion. It can also create a clog. So as I said, I’ve not seen any evidence of this with mine. I’ve left mine in. If you want to take yours out, go look at my video on this channel for replacing nozzles. I take you through the whole process of how to remove the insulation from the heater block. At that point, you can remove the two screws and then you’re going to have to install replacement insulation. What I show you in? That video is how to put on a silicon sock over the heater block to replace the factory insulation. That you have to remove to get these screws out. So I’m not gonna cover all that here. That’s all been covered already in the nozzle. Change video. You can go check that out if you want to take these screws out now. One other issue with Bowden Tubes is when you get down to the end of the role of filament and the filament is more tightly curled. That can cause problems if you have a Bowden Tube feed system because that tighter curl is trying to run through a straight tube and that’s causing drag. That’s gonna cause potentially some under extrusion. So if you’ve been printing fine and all of a sudden, you’re at the end of your roll and you’re seeing the under extrusion. Try on taking the filament off the Roll, straightening it out a little bit and seeing If that resolves it, odds, are it will now the final cause or an. I shouldn’t say final. There’s others. But the final of the more common causes of under extrusion is a partial or fully clogged nozzle or hot end. How do you tell well what you want to do? Is pre-heat your hot end up? Do it 2 to 10 to 15 release the tension on your extruder in the case of the under 3 You just squeeze this arm in so you can manually push the filament through the system. If it comes out cleanly through the nozzle straight line coming straight down, no problem, you don’t have a clog if it comes out is a thinner line that wants to curl up just on the end of the nozzle. Then you have a partial clog and. I’m going to tell you how to fix that. What we’re gonna do is called a cold. Pole and I hate this term because it’s misleading every time I tell people they need to do a cold Pole. They think they’re doing a room-temperature. Pole and try yanking the filament out, that’s not it. This pole is actually done while heated, just not heated enough to melt the filament. So what you’re gonna do if you have a? Bowden tube feed system. You want to remove the plastic from the system? Heat the nozzle up. Remove your plastic filament. Then remove the Bowden tube. You do not want to feed the plastic through the Bowden tube for the cold. Pull if you don’t have a Bowden Tube system. All you got to do is release the tension on your extruder feeder and manually insert a length of filament a piece of filament about 1 foot long. You’re gonna manually insert it down while the hot end is heated to 210 or 215 into the nozzle. You’re gonna force it in there until you see it. Come out of that nozzle or and if you can’t get it to come out as far as you can then on your. LCD screen on your temperature control. You’re gonna dial that down to 90 degrees. What’s that gonna do? Well, As the temperature drops, the plastic in that nozzle is going to solidify, but it’s not going to be totally hard it. If it’s kept at 90 degrees, it is above its glass transition point. It’s still gonna be slightly soft. When that temperature hits 90 you’re gonna give a sharp yank up on that filament and then look at the end. If it’s clean, you didn’t have a partial clog if it has little bits of dirt in it or darker debris. What that is this charred filament that started blocking it. So what I want you to do is if you had that. On the end that charred filament that darkened areas. Cut yourself another section of filament reheat the system up to to 10 to 15 feed that filament in put it down to 90 and do another cold. Pull, keep doing that until your filament comes out clean, and then you know, the nozzle is clean. Reassemble your Bowden tube if you had it and you’re done if you need to change the nozzle, if it’s if it’s too bad clogged and you can’t do a cold pole to fix it, then you need to look at my nozzle changing video and it walk you through step-by-step how to put a fresh nozzle on your hot end? Okay, so that’s it That is pretty much all of the causes of or the more common causes. I should say of under extrusion on an FTM 3d printer. Now, please click that. 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