Creality Ender 3 V2 - Fixing the Hidden Problem that Can Cause Stringing and Unresponsiveness

hey guys and welcome well i have to say i'm pretty happy with my inner three version two but not everything is working perfectly so in this video we're going to do something about that so stick around while investigating retraction settings on bowdoin versus direct drive i was wondering why there's such a big difference it doesn't seem to make much sense mathematically direct drive uses around one millimeter retraction with good results my bolton uses about five millimeter we've got friction within a long tube and this should be pretty minimal depending on what you're printing uh and maybe the quality of the tube as well this one's somewhat unknown and kind of hard to measure and test for so now we have the size of the filament 1.75 millimeters and some tolerance there versus the inside diameter of the tube itself now based on a 14 inch tube there is a maximum possibility of losing about 0.6 millimeters when retracting versus extruding and now to the big one adapters and fittings these seem to have some movement in them and when looking inside it isn't really that hard to understand why so let's get right to the point the original fitting attaching the bowden tube to the bowden gear drive assembly allows way too much movement there's too much slop over time that tube is being eaten away by the spring steel tines on the inside and is starting to allow movement of that tube in and out so if you were to leave that long enough the tube end will completely wear away and lose the connection with the fitting this is extremely difficult to see however if you're able to mark the tube and watch it you'll understand ptfe aka teflon is the same material you'd find on your non-stick frying pan it's extremely slippery and very heat resistant trying to glue or tape it though in place just does not work now before we go and buy something i want to address the length of the tubing the math suggests that a longer tube won't necessarily add much tolerance on our retraction and a longer tube also means less movement at the fitting to help preserve a good connection i decided to purchase these parts knowing full well that the tube tolerances could be a problem but the price was right and the ratings seemed to be real so it's time to remove the old tubing fittings remove the two dome head machine screws carefully so you don't lose them and take the fan shroud off this is straightforward as long as you take the fittings off and this is because ptfe or teflon tube expands with high heat and the metal tines do dig in and deform the tube as well so you can slide the hot end fitting off only in one direction after you take the fitting out before we go reassemble everything i'm going to go one step further and try to get a superior connection to the gear drive fitting by expanding the ptfe tubing on just that end i've marked the end with the teeth on the fitting itself for reference and i'll use a lighter to heat the end until it changes color the blue turns a bit darker if you have white tubing it will turn clear so ptfe will melt and it will catch fire so please be careful while you're doing this with the end expanded slightly we need to align it while it hardens and will make a new clean cut on the end as well i'm shooting for the teeth to engage on the transition between the two sizes in order to help it stay in place all we need to do now is attach the new fittings run the tubing through the fitting right into the hot end making sure that it bottoms out completely the gear drive fitting does not allow the tube to pass through and we'll make sure that we bottom that one out as well i will say that this tubing is a little snug the inside of the tube measures at 1.84 1.85 millimeters the capricorn tubing measures around 1.9 and most of the others seem to measure at around 2. the smaller diameter means a little bit more pressure required to push the filament through and that could lead to problems over time from previous testing with this printer i know that anything less than five millimeter retraction gives a poor result so let's throw some samples together to see if there's been an improvement and which is the best number to use for retraction now that we've changed the fittings and the tubing these samples are printed with the fan set to only 10 that's because i like my prints to have good layer adhesion i've also been printing with petg recently and it can leave little fine strands but otherwise seems to be a really good 3d printing material the first sample uses a zero retraction and that's just for comparison now the one millimeter you can see that there is an improvement the two millimeter again an improvement but not quite there yet and three millimeter looks really good almost perfect all right i believe the fitting problem has been corrected and the bowden tube is about 18 inches long now it's time to reduce the retraction distance from five millimeters to 2.5 millimeters i should mention that because i print mainly structural parts i use a 0.6 millimeter nozzle and because of that the seam visibility will be a little bit higher in the same way that you would have sharp corners appear slightly more rounded with the larger nozzle size now after all those changes i wanted to have another look at the fitting to check for movement this is after about 40 hours of prints and you can see there is a very small amount maybe 0.25 millimeters and any movement is bad so i do think that this fitting can be improved again but that will have to be left for another time well i hope you found this video helpful and if you did make sure you hit that subscribe button and like the video take care everybody we'll see you on the next one you

Channel: NeedItMakeIt

Views: 520,476

Keywords: Cleaner prints, Cleaner 3D prints, 3D print quality, Better 3d Prints, remove strings from 3D prints, remove stringing, no more stringing, combing 3D prints, How to print with ABS, Creality Ender 3, Creality, creality ender 3 v2, Improve print quality, improve print speed, quicker print time, speed up 3d print, faster 3d print, better 3d print, how to 3d print, 3d print structural, Print in a cabinet, Print on glass, 3d printer, How to print faster, Cleaner faster prints

Id: uEo5vNGsO6Q

Length: 6min 7sec (367 seconds)

Published: Tue Nov 17 2020

Reddit Comments

[u/pnt103]

You're right about poor fittings damaging the tube, but the movement you showed does not happen with good quality fittings with the tube properly fitted and maintained. Mine certainly don't. What does does happen over time, especially at the hotend end, is that the slight rotational movement, as the hotend moves back and forth, wears a groove that can become a spiral, or a wider groove, so tubes are considered consumable. Of course you can cut the end off a few times to eliminate the groove.

If you push the top of the fitting down against the brass, which may require some force, the tines are retracted, and unless the tube has been fairly badly worn, the tube can then be removed from the fitting.

Your calculation of 0.6mm difference between retracting and extruding is wrong, too. You assumed incompressible filament in a smooth curve against inner or outer curve of the bend. That's not what happens. It forms a wiggly line inside the tube when pushed (extrusion) and straightens under tension, and furthermore it's somewhat elastic, so the difference is considerably more than 1mm.

[u/as350b2]

This may lead to my first lathe project