I've Fixed Z Banding on my 3D Printer...FOREVER

well here we are again I'm back with a quick tidbit of information for you I've been busy aggressively searching high and low for the right combinations of Solutions in order to remove Z banding from my Ender three I've tried everything including the kitchen sink in order to smooth out this egregious Z Banning I was getting on my prints but after all of this testing I believe I finally found the right combination to minimize Z Banning artifacts on my prints and hopefully on yours as well I'm scouring all the corters of the internet leaving no suggestion untested and no product UNP purchased in order to understand this problem first we got to go back to class Z banding what is it why does it happen and why should I care there's actually a bunch of different terms that are often conflated online but refer to distinctly different phenomenon Z Banning is actually a symptom of several other issues but it generally manifests as a continuous pattern throughout the height of the printed part it looks and feels like bands but there's several other terms we should also be familiar with Z wobble refers to when the lead screw rotates eccentrically about its axis rotation this can be seen by looking directly down at the top of the lead screw Z ribbing refers to banding but more specifically when you have physical ribs that protrude away from the part as seen here Z binding occurs when there's too much resistance between the lead screw and the lead screw nut this is usually caused when the motor lead screw setup isn't parallel to the Gantry this binding or resistance can lead to partial or missed Z steps on one or both z-axis lead screws these missteps will result in squished layers which look like ribbing as seen on this Beni or slanted Parts because the z-axis motion is asymmetric causing the Gant to Sag towards the side that is experiencing The Binding which with the lead screw perfectly vertical it's pretty easy to push this nut down but as soon as I slant the lead screw it becomes really hard to push the nut down nearly impossible with so much resistance between the lead screw a nut Z binding is going to produce more ribbing because it's physically squishing the layers together because of incomplete zeps this was the exact problem I was experiencing on my Ender and what prompted me to start chasing this problem in the first place so referring back to Z banding you can have a continuous pattern of ZB banding or a non-continuous pattern that it's more randomized generally speaking a continuous pattern of Z banding is caused by mechanical issues with your Gantry and Lead screw while inconsistent patterns are likely due to Extrusion issues so why do we get this Banning in the first place let's go back to that Z wobble each of these Bands Will roughly coincide with a full rotation of a wobbly z-axis so what's going on here why does this happen well as the screw rotates eccentrically it's actually putting lateral force in the Gantry moving the Gantry and therefore your nozzle out of alignment for the duration of the rotation that leads screw which is why we have this consistent pattern so for the rest of this video I'm be focusing on the mechanical issues with the Gantry and the lead screw but first some preliminary items just for consistency sake I want to touch on leveling my Gantry I'm using this digital level to level the Gantry how by measuring it against the surface the printer sits on I zero it against the table and then measure the level of the Gantry we want them to be almost perfectly parallel I adjust the Gantry by manually moving the z-axis steper motors up or down until we reach 0 de in the readout so why do I do it this way because I can come back at any time and check the level of the Gantry to see if it has moved at all this allows me to easily diagnose issues with my z-axis and make any adjustments if necessary okay so with that out of the way let's talk about some of the issues that could lead to the inconsistent banding we mentioned before number one clean and lubricate your lead screws your lead screws can get pretty disgusting over time they'll accumulate dust and dirt for being exposed to the open air and even brand new ones from the factory can be dirty so start with some isopropyl and get all that builtup gunk out of the threads doing this by hand can be an absolute chore so I would recommend a tool such as this 3D printed lead screw cleaner this makes the process so much easier and once it's clean we can really see the difference now for lubrication there's a couple of different types you can use I'd recommend a white lithium or a PTFE grease you can also use oil as well I'm using this Super Lube synthetic oil with PTFE which is what will be applying throughout the rest of this video then I run the Gantry up and down a couple times to spread it all out number two clean your nozzle I actually replac the nozzle with a brand new one in preparation for this testing then run a p tune for both the bed and nozzle performing the P tune will help to eliminate any temperature fluctuations that can lead to inconsistent extrusions speaking of Extrusion make sure you calculate your e steps and make any adjustments as necessary over or under Extrusion could be contributing to your Z banding make sure there isn't any unnecessary resistance on your spool or anywhere else between your spool and your extruder finally step three make sure your X Gantry is all tightened up we don't want any slop or play at all any movement that isn't in the z-axis OR up and down can physically move the nozzle away from where it's supposed to be so make sure all your bolts fixing the Gantry together are tightened up next you want to make sure all the Palm wheels are free to rotate but don't have any play side to side they should be able to spin freely with just a little bit of force finally our Ecentric nuts on both sides we want to tighten these up so that the rest of the play in the Gantry is taken all the way up but not so tightly that there's too much resistance against the frame okay this stuff is honestly just a formality so we can check all of our boxes now let's get to the fun part how I actually addressed the Z banding on my Ender all this testing was done on my Ender 3v2 but nearly all this advice will apply to any printer that uses lead screws to move either the Gantry or the bed all my test prints were done with the same settings and slicer and the exact same spool of filment and any and all products seen were purchased by me with my own money nothing was sponsor except for this video before we continue I'd like to shout out this video sponsor PCB way I've personally used PCB way to have batch runs of pcbs made for a previous project I was working on but PCB way doesn't just offer PCB prototyping they also have a variety of other manufacturing services including CNC Machining sheet metal fabrication injection molding and of course 3D printing it's super easy to order simply upload your project files choose your processing material and get an instant quote it really is that simple so thanks again to PCB way for sponsoring this video now back to the enclosure we want our lead screw and motors to be perfectly parallel to the Gantry extrusions of the printer now what I noticed while going through this process is that the stock reality motor mounts that come on the original Ender and the V2 Do not sit flat on top of the motor meaning that when you tighten them to the frame they have a tendency to slant the motor towards the frame knocking out the alignment with the lead screw and the Gantry Extrusion a slight draft angle that was likely a byproduct of the injection molding process so step number one is to 3D print some alternate motor mounts there's a couple of different ones available on places like thingiverse and printables but the exact ones that I settled on in this video are available in the description they use 4mm t- nuts and allow the motor to sit square with the Gantry Extrusion remember the motors can get hot so it's best to print them in petg or ABS as pla will soften up so now with our new motor mounts in place we want to make sure that our Gantry brackets are actually square if the Grant Tre bracket where your threaded nut screws into is not square and the hole is bent at an angle it can put force in the lead screw causing binding so measure squareness with a square and if it's off just bend it back into place with some pliers do this for both Gantry brackets now we need to check and see if the lead screw lines up with the motor coupling by performing the vertical drop test which is what I'm calling the test to see if the lead screw naturally lines up with the hole in the motor coupling going through this process I wasn't at all surprised to find out that it in fact did not this isn't so much a test as just the process for assembling the printer correctly when your lead screw is just hanging out not attached to your motor coupler as you rotate the lead screw down it should line up perfectly with the top hole in your motor coupler allowing for a nice snug fit if you got to force the lead screw into place you're way off base so first things first loosen your zcw nut just enough they can move side to side but there's no sagging up and down next take the X Gantry near to the top of its vertical travel unscrew the leader from the top of your coupler and rotate the lead screw away until it's no longer sitting inside the coupler you'll notice that your ex Gantry is going to Sag a little bit towards the side that you just unscrewed the lead screw from before you move on to the next part we need to level out the Gantry so you can hold the Gantry up so that it's level or what I did is tie the Gantry up with some string to make it level if the Gantry isn't level during the next step it's going to throw off the alignment with the coupler now with the top couplet screw loosened all the way you should be able to easily rotate the lead screw down into place resting on the bottom of the couplet rotating the lead screw down it should be perfectly lined up with the hole if it is you're all good and if it's not we're going to have to shim out the motor away from the frame in order to get this to line up properly so I made these custom shims to move the motor mount out so the Gantry bracket lines up perfectly with the motor coupler mine were 65 mm but your mileage will vary so you actually have to take the measurements and make or buy the appropriately size shims I use my shim measuring kit to figure out exactly how much of a gap there should be but it doesn't have to be that per after you've shimm this side then tighten up your lead screw coupler and go back and perform the steps in exactly the same way on the other side on this printer I have dual z-axis but the vertical drop test is just as applicable if you only have one z-axis perform all the steps in exactly the same way it's just that with dual Z you've doubled your fun and potential problems as a quick disclaimer for me installing the new motor mount and making sure my brackets were Square allowed for perfect alignment and I didn't actually have to use any shim in the final build but I let this step in in case someone would benefit from this information now it's true you can address these issues with an unlevel Gantry with things like the g34 command in Marlin but only if you have the motor driver for each Z motor or doing a mechanical reset by ramming the Gantry against top of the printer until both z-axis are level but you're really just masking the root of your problem which is too much force on either z-axis you have to undo the binding to allow your ZX elad screws to move freely now doing this process for both sides yielded some better results as seen here but I think we can get even better running some more test show I fixed my Z binding but there was still that pesky persistent pattern I mentioned before so let's take it a step further with a motor lead screw and coupler we want their Center axes of rotation to line up perfectly due to a variety of factors the lead screw will wobble which is basically with the entire assembly free sanding the tendency of the top of the lead throughout to rotate eccentrically outside of its axis rotation in an Ideal World in order to perfectly trans MIT that rotation of the z-axis into linear motion of the Gantry we want this lead screw to rotate perfectly around its axis rotation or as perfectly as we can get it that means straight lead screws and perfectly aligned couplers and Motors the coupler connector is one of the worst sources of this wobble in this type of setup because on top of potential bends in our lead screw we're also now relying on this coupler to line up the centers of the lead screw perfectly with the center of the motor spindle and sufficiently hold the lead screw straight without slanting it to either side and as you can imagine this is pretty difficult to achieve now this is not uniquely a 3D printing problem there's entire manufacturing Industries around the creation of different styles and types of motor lead screw couplers for different purposes mostly for CNC machines which is what a 3D printer is one way to bypass this problem entirely is to have your lead screw as an integrated part of your motor meaning no couple are required this is actually how CR has been tackling this problem in their I3 printers for some time when we freestand the inte gred lead screw motor and rotate it we can see there's virtually no wobble and side by side compared against the motor lead screw with a coupler there's a ton of Ecentric wobble but if you have a budget bed Slinger your Cali your eligo Etc you're stuck with the coupler problem but that's okay I think we can make do with this let's look at some modifications so knowing we're going to have this wobble in our z-axis we want to give the axis some freedom to rotate in the X and Y directions in order to most effectively transmit the Z motion this could be achieved with these Oldham couplers Old Ham couplers allow the z-axis to rotate freely without over constraining it they are made up of three dovetailed pieces that slide in the X and Y Direction and connect directly to your lead screw nut in Gantry bracket these stop the wobble of the lead screw from being transferred to the Gantry during installation I'd recommend applying some grease to each part the only job this thing has is to slide back and forth if it's not doing that effectively it's basically worthless ooh that looks pretty good so in a previous video I recommended the anti-backlash nut and I still think they serve their intended purpose but during testing I noticed there was a slight reduction in Z banding when they weren't installed so I removed them for testing and repl the brass lead screw nut with a palm alternative the brass nut / lead screw combination absolutely needs to be lubricated but over time the brass nut can degrade leading to some play in The Nut the Palm nuts are described as self lubricating which sounds nice as marketing fluff but isn't technically correct they just have a really low coefficient of friction and high abrasion resistance so do you need to lubricate Palm nuts well prusso explicitly says you should not lubricate the Palm nuts or lead screws on their machines why well the reasoning isn't given but it's probably because the lubrication isn't technically necessary and it can lead to Gunk buildup when the lubrication combines with the dust and plastic debris over time so the question is Tu Lube or not tube well after cleaning my lead screws and installing the Palm nuts I noticed there was some noise during Z travel applying a little bit of PTFE oil along the length of the lead screw took out that noise just remember that with the oil you'll likely have to clean your rods more often and reapply oil more frequently now the stock ster Motors that come on your creality machine aren't really designed to support for Supply down on top of the motor spindle so you can install a Thrust bearing that helps to support the weight of the Gantry on the motor while allowing free spinning motion I'm not really sure if the thrust bearing makes a difference but I already had to replace the stock motor mount so I figured I would give it a try but there is a slight difference in quality between these two examples the only change between these two prints was the installation of a Thrust bearing so if anything it can't hurt your setup and will likely protect your motors from unnecessary wear over the long term so I'd recommend it if you've looked into removing Z banding on your printer you've likely come across these Plum or spider couplings these couplings have two separate metal couples that are held together by this plastic piece in the middle in theory unlike a rigid coupling they're supposed to compensate for the lack of alignment between the lead screw coupler and motor by allowing the coupler to flex I saw some setups that called for a plum coupling and for the lead screw to be fixed at the top of the Gantry with a bearing stabilizer so while the wobble is basically focused at the coupling during testing the setup produced more noticeable Z Bandon down the entire length of the test part removing the stabilizer improved the surface quality and this test produced a part with no banding and minimal surface [Music] artifacts so what about our lead screws replacing a bent lead screw how do you know when the lead screw is so bent that it needs to be replaced well most lead screw motor coupler combinations will have some amount of wobble and most of your cheap lead screws that come on your printer or those you buy online from places such as Amazon will be bent to some degree but it's too bent when it starts to cause issues like this really bad banding scene here and the bent lead screw can't be mitigated by a flexible coupler really it's that simple if your prints look good you don't hear any screeching sounds your Motors are not losing steps then you're good and just leave them be keep them clean and keep them lubed now this next suggestion is going to surprise some but bear with me removing the lead through stabilizers at the top of the frame improve the surface quality of my print and reduce Z banding this was a little bit surprising at first but after some investigation it began to make more sense unless your lead screw is perfectly straight meaning no Wobble the stabilizer at the top is just going to over constrain the lead screw and cause binding looking at this the stabilizer screwed all the way into the frame it's putting pressure against the lead screw and across my testing the bearing stabilizer created thicker Z banding and worse surfice artifacts in every single test print where I had them installed I even tried a flexible coupler with a bearing stabilizer to the top and this still produced noticeable Z banding it is my suggestion that these belong in the trash and not on your printer but I didn't really like the idea of my lead screws just hanging out all exposed so I designed these lead screw covers that allow the top of the lead screw to rotate unconstrained but also protected from snags or damage or dust they also have a built-in physical Z stop so you can drive the Gantry against it and perfectly level it manually Link in the description but remember we talked about the wobble problem well curiosity killed the cat and my wallet to test the difference a perfectly straight lead screw would make on Park quality I bought two of these combined lead screw motor units the lead screw is incorporated directly into the motor and when we look at this from the top down the wobble is basically non-existent these new motor units were mostly plugged in play I did have to swap out the motor cables and physically take the Gantry off but after testing I found these new Motors produce the best service quality out of all the solutions and combinations of everything I tested so is that my recommendation that everyone should run out and completely replace the stock motor lead screw combo no absolutely not because simply the cost isn't worth it but more so because I was able to get nearly the same service quality with my old ham coupler setup so what's my final recommendation for reducing Z banding and improving overall surface quality along the Z wall Zer prints well there's three options the first one that I would recommend is the old hem coupler setup which includes installing a new motor mount with a Thrust bearing using the stock rigid coupler and replacing the brass screw nut with a palm alternative which is optional and installing the Old Ham coupler on your Z Gantry bracket my next suggestion would be using the flexible coupler which again includes installing a new motor mount with a Thrust bearing installing the flexible coupler by replacing the rigid one placing the brass screw nut again with a pal or finally the third option is the combined motor lead screw combination which is basically just installing the lead screw motor combination and using a palm nut which again is optional but because of the cost I wouldn't necessarily recommend going down this route unless you are just an absolute Financial masochist comparing the plum coupler to the Old Ham produced nearly identical results but in my entirely professional and not subjective at all opinion I think the old ham setup looks the best and is definitely the best value after all of this I think the only way to see any further improvements in service quality would be to switch over to something like a linear rail setup but let's remember something here even with the perfect setup there's going to be surface artifacts on your prints due to a variety of things like inconsistent wearing your palm Wheels a Gantry that isn't perfectly level in consistent pitch of your lead screw bending your lead screws Etc High Precision is expensive and fortunately for hobbyists everywhere these printers are not they design to be built with imprecise parts and still give acceptable build quality if you made it this far in the video consider subscribing so I can continue to justify burning my own money for your entertainment and as always I hope you learned something and thanks for watching

Channel: Maxy Meanderings

Views: 110,572

Keywords: 3D Printing, Creality, Ender 3 V2, Upgrades, Maker, Creator, Inventor

Id: omKbSE_DWkY

Length: 19min 40sec (1180 seconds)

Published: Fri Mar 01 2024