After the assembly of your KAY3D CoreXY machine, you'll probably run into certain issues. Well, this page is not supposed to scare you on your FDM printing journey, but to help you fine tune your machine mechanically.
There are many possible issues that can occur in 3D printing; You can have first layers that never stick, layers that have adhesive issues, bed that isn't exactly flat (looking at you, Creality) and of course, the nightmare of 3D printing that triumps it all; nasty 3D printed artefacts.
Yes, we're talking about Z banding (wobbles) and other artefacts. This page is going to address these issues and we hope it'll serve as a good guide for you if you run into any of these issues!
Removing Z bandings
There are many known methods in removing Z banding. We will just cover the more common methods as they usually help solve Z banding entirely. Please try out each method one at any one time.
1. Loose belts. This is the most common culprit for Z banding. If you have belts that do nottwang or vibrate at all when you pinch it, then your belts are way too loose. Tighten the belts highlighted in the assembly process and do your test prints again.
2. FNH-001 and RNH-001 may be the culprits. If the M3 bolts and nuts clamping on to the lead screw’s nut is too tight, you will get Z binding. Loosen these nuts and do test prints again.
3. FNH-001 and RNH-001 are out of alignment. In the assembly process, FNH-001 and RNH-001 are aligned with the help of the guided lead screws. However, mistakes can still happen. To re-align these two plates, loosen their bolts and ensure the plates are in the middle of the lead screw before tightening them onto the 2020 extrusions again
4. Lead screws that are mechanically bent. Even lead screws sourced from reputable sources cannot be guaranteed to be 100% straight. The binding is often aggravated if the lead screws are guided at the top. In the default set up, the lead screws are guided at the top with the help of the MF128 bearings.
To check if the MF128 bearings are causing the binding, remove both of these bearings at the front and at the rear of the printer and do test prints again.
The MF128 bearing seats in FZAJ-001/ RZAJ-001. Remove it to check if you can solve binding
Still not solved? Loosen the Z axis belts by removing the belts from the ZM-001 assembly. Be prepared to catch your heated bed as it will come straight down once the Z belts are no longer tightened.
Remove the lead screws from the 3D printer one at a time, and roll them on a piece of paper placed on a flat table. If the lead screw appears to be visuallybouncing, then chances are you have a bent lead screw.
Please let us know about it. If the kit is still under warranty, we’ll definitely send you a new one.
Removing Other 3D Printed Artefacts
If you have 3D printed artefacts like these, then there are a few known solutions. These artefacts can happen because of a few things. Please try out each of this solution one at any one time.
These artefacts are not because of ghosting. Ghosting rather, is something that can be fixed in your slicer settings.
1. Check your X carriage plate if it’s tight or if it’s wobbling around. Check if the eccentric nut is too tight. If yes, loosen it. If everything’s tight, remove your fan duct and check if the hotend itself is tight.
2. Check your V-wheels on your X and Y axis. Are they worn out? V-wheels are consideredconsumables or equipment that wear out. If they look like they have cuts, dings andbattle scars, then they are worn out. Please replace them.
3. If they don’t look worn out, please check if your eccentric nuts are adjusted correctly. We have an entire section dedicated on this in the assembly manual.
4. The CoreXY kit uses V-wheels that glide on V-slot extrusions. If the V-wheels look ok, then check the extrusions they glide on. Pleaseremove wiresfrom A and B Motor. Then move the X carriage slowly front, back, left & right. If the movement is choppy or feels like there’s a form of resistance, visually inspect the extrusions and the V-wheels.
For example, if the movement feels weird on the Y movement, check for the responsible extrusions and the V-wheels. Do the same if the movement feels weird on the X movement instead.
5. Check your 2GT belt tensions. It is not difficult to tighten a CoreXY machine especially on the KAY3D CoreXY Conversion Kit. Sometimes, 2GT Belts that aretoo tightcan and will cause 3D printed artefacts. Loosen the belts and see if the artefacts are still present.
6. Usually, the bearings on the belt routings can last for a long time as they’re industrial graded bearings. The pulley idlers on the other hand, can be subject to wear and tear. Remove the 2GT belt from the belt routing, then gently nudge by rotating all 4 pulley idlers found on the front left & right, middle left & right idler assemblies.
7. Each of them should rotate without any resistance, freely. If they cannot rotate freely, loosen the belt holding on to them. If they still cannot rotate freely despite a loose bolt, then the bearings in the pulley idler has stopped working. Those would need a replacement.
8. If the idler pulleys all move freely, then check the idler bearings. Despite being bearings of industrial standards, dust and dirt during the 3D printer’s operations can cause dirt to get clogged up. This can result in less-than-ideal bearing performance. Check if the bearings on all your idler assemblies turn smoothly. All you need is one bearing to be under-performing to affect 3D printing results.
9. The machine is mechanically sound if it does all the above steps well. If you still have issues, talk to us. We’ll love to help.
Belts Destroyed by Pulleys
If you have belts that are wearing off prematurely on the idler stacks, there is something you need to look into:
1. Belt wearing happens prematurely when the idler stacks are not positioned correctly. If you look at the above image, you'll observe two things. The green arrows, which represent the top and bottom edges of the F595 bearings sit right between the red arrows; represented by the 2GT 20T pulleys.
2. If your idler stacks on the front left or the front right do not correspond to a similar stack, your belt will shift as your printer starts printing. Belt shifting, also widely known as belt riding can cause premature belt deterioration and belt failures.
3. To combat a non similar idler stack, all you have to do is fine tune their respective z-positions by inserting spare spacers (0.25mm & 0.5mm) either below, above, or between the components. Inserting them at the right place gives you the ability to fine-tune them and effectively removing the possibility of belt riding.
4. While there are other things that can cause the premature wearing of belts such as bent plates, worn-off F695 bearings; a usual less-than-ideal stack is the first culprit.
We hope this illustration is clear enough and can help you solve the issue of belt wearing.