How to Diagnose & Fix Serious Under Extrusion #FixMyPrint

in this video i'm going to show you how to diagnose serious under extrusion like this let's get started so as well as the massive gaps that form in under extrusion stringing between the parts is also a good indicator as it's something that happens when there is additional pressure in the nozzle not being released don't forget for 3d tomorrow filament four print waste can be stored to be returned and recycled here's a quick sneak peek of the process but for now we're going to start with the fan we need to check it is clean freely rotating and of course has no broken blades if it's dusty it's never a bad idea to give it a little brush of course if the fan is particularly dirty and from time to time anyway it's a good idea to completely remove the outer casing and clean in behind you'll be amazed the amount of dust that can build up over time especially if you're printing in a dusty environment you see at the moment the fan is stopped switch the printer on the fan should come on and be rotating like that don't do this but there if it was like this when the printer was turned on you know something's gone wrong but the fan is spinning fine so in this scenario we know it's not the fan once we've eliminated the fan from our concerns we need to look next at extrusion in this step of the process we're going to check the extrusion is straight and clean we're also going to if need be clean the nozzles and check the ptfe is clean and uniform first step is to heat up the hot ends for 3d tomorrow uk pla the advised temperature is 215 c once that's warmed up we can then carry on with the process you'll see here i'm manually pushing the filament through by hand to check for clean and straight extrusion in my case this was not the cause of the under extrusion however i've installed a partially blocked nozzle to show you what this would look like you'll see this time when i try to push the filament by hand it is not coming out smooth and in a clean line in fact it's curling up heavily and it felt very difficult to push through there are countless nozzle cleaning tutorials but i'll show you a few of the things i do the first one is while the nozzle is hot remove it and by hand pull out the little toggle of filament that's left in there if you do this well you can often remove a lot of the dirt which is very handy for bowden setups you'll see here it comes out with a good bit of force and removes a lot of dirt from the end of the nozzle a few pulls later and it's looking quite clean so time to go back into the hot ends when installing into a hot end place it in cold and tighten when hot you can then try again with another manual push test as you can see here although slightly improved this nozzle is still partially blocked and is curling heavy at the start even though it starts to appear somewhat straight here this is still not a clear nozzle and if you were to look at this more closely you would see that it wasn't perfectly round and actually has a slight indent in it so we need to try something else something i like to do with bowdoin setup is completely remove the tube and rod it with a hard metal bar you can also use an allen key for this if you have one that's around 1.75 millimeters see here this metal bar is perfect just push it through as if it was filament and use that additional force to really push the plastic through the nozzle always pull any strings out left in the machine another great trick is to use a little slice of ptfe bowden tube and push it into the hot end as if it was your normal tube then re-insert the securing clip and you're ready to push some filament through the reason i do it like this is because it means you can get a lot more pressure onto the filament than you can if you're pushing it all the way through a long bowden tube you can see here that the filament is now coming out nice and straight out of the nozzle all good obviously if it doesn't come out clean straight away then just do a few more pulls before putting it all back together i always like to give one final push with the metal rod just because you can get a lot more force using it while you've got the bowden tube out it's a good idea to inspect it to make sure it's clean and uniform ptfe tube will wear away after lots of use so if the end is looking particularly dark or discolored or enlarged in some way then it's a good idea to replace it what you can do if you have enough length left in your bowden tube is just slice off that end section using a stanley knife a sharp knife is better than scissors because you're less likely to deform and de-shape the ptfe tube as you cut it if your ptfe tube does get too short then you would have to replace the entire thing once that's all done the tube can go back in clip back on and you're ready for the next step which is inspecting the drive gear you want to check for dust as that's a good sign of something going wrong you want to look at the gears and make sure they're sharp and free from dents the area that grips the filament can become flattened or worn away and you also want to make sure the drive gear has proper tension signs that it's not properly tensioned include wearing away of the filaments or just a general slipping when it's trying to push the filament through in my example you can see that the drive gear has been the cause of my serious underextrusion the dust there is a good sign so let's brush that away what's actually happened is that the drive gear has worn away part of the aluminium housing because the design allows the steel to rub on aluminium and aluminium is softer and so has worn away you can see how far it's dropped which meant that grip that's meant to hold the filament is no longer lining up with the filament itself which is what would have prevented proper extrusion at different parts of the prints when you have serious wear and tear like this you might need to replace the whole unit or at the very least the drive gear detach it and replace it however i always like to aim for zero waste so i'm going to try and fix this little unit here i've taken off the one arm and can clean up the rest of the dust obviously dust could get into the stepper driver motor and we don't want that because it could cause all sorts of issues now what i've done to fix this is added little o-ring in the gap that was worn away and as you see when the drive gear goes back in it's spinning perfectly and there's no movement there and voila working away held in place as it should with perfect extrusion once again there we go if after trying all those things you still have had no joy there is actually one more thing you could look at and that is your filament spool holder some spool holders provide too much friction on the spool itself and so you just want to make sure there's no snags happening there if you've also checked that and your filament can run and uncoil smoothly and freely then it's very likely that this is going to be a software thing the main software settings that can affect under extrusion are speed printing too fast can cause under extrusion the temperature mainly printing at to lower temperature and also your retraction settings can sometimes also lead to under extrusion if you are inadvertently causing blocks try turning it off and see how that affects things and then dial in perfectly thereafter if you think software settings might actually be your problem then you might want to take a look at this video i did before on calculating the max flow rate of your system this will help you dial in and get the fastest you can print the highest flow rate you can print and avoid this sort of under extrusion i hope you enjoyed the video today and found it helpful and hopefully it solved your problems if you did enjoy it give it a like and consider subscribing cheers and happy printing i'll see you next time

Channel: Callum Coles

Views: 89,890

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Id: 6V319bseO3U

Length: 8min 40sec (520 seconds)

Published: Mon Mar 29 2021