There are many causes for Z banding on an Ender 3 and each of them seems to be equally as frustrating as the others. Thankfully there are pretty simple solutions for most Ender 3 issues so let’s dive in and see if we can figure out how to fix your Z banding issue.
The most common causes for z banding on an ender 3 are your z-axis eccentric nut being too tight, z-axis lead screw binding, z-carriage brass guide over-tightening, and z-carriage alignment. Most Z banding issues are relatively simple and only take a few minutes to fix.
1 – Z-Axis Eccentric Nut Over-Tightened.
The z-axis eccentric nut being over-tightened is by far the most common cause for Z banding on a 3D printer.
The eccentric nut being over-tightened applies excess force from the z-carriage to the extruded aluminum that guides the z-carriage.
You can loosen this nut with the tools provided with the Ender 3 kit. Just slightly turn the eccentric nut with the Ender 3 wrench and turn the z-axis lead screw by hand to test the tension of the z axis carriage.
2 – Z-Axis Lead Screw Binding.
The z-axis lead screw binding is another common issue that causes z banding. You can test for z-axis binding by turning the z-axis lead screw by hand to ensure that the z-axis carriage moves freely along the lead screw.
If there are any spots along the z lead screw that are binding you will want to check for any damage or debris on the lead screw that might obstruct the movement of the z-axis carriage.
Another cause of z-axis binding is tension against the lead screw caused by the lead screw alignment. A common solution for older Ender 3’s is by printing an adjustable motor mount for your Z axis motor so that you can position the motor directly in line with the brass carriage guide.
You can find the printable z-axis motor mount here.
3 – Z-Carriage Brass Guide Over Tightened.
The brass guide in the z-axis carriage has 2 bolts that should not be fully tightened. You can adjust the tightness of the bolts with the Allen wrenches provided with the Ender 3 assembly kit.
Per the Ender 3 assembly instructions these bolts should not be completely tightened. You don’t want the bolts to be nearly falling out but they should be backed off about half a turn to a full turn from completely tight.
The purpose of the brass guide being slightly loosened is so that there is a small amount of play in the guide to prevent binding on the z-axis.
4 – Intermittent Nozzle Clogging
Intermittent nozzle clogging is a very real possibility with z banding, especially if the z banding is not consistent throughout the print.
If the nozzle becomes partially clogged it can cause a thin semi-clogged layer, followed by a thick not clogged layer. To ensure that the nozzle clogging is not the cause for z banding you can replace the nozzle or change the filament you are using to ensure that the filament is not the purpose for the clogging.
5 – Z-Carriage Alignment.
The z-carriage alignment is typically a manufacturer error on the machine that causes misalignment and pressure on the z-axis lead screw.
At the manufacturer, the z-carriage starts as a flat piece of aluminum which is then bent into form to accommodate the extruder motor and the brass z guide.
The issue with starting with a flat piece of aluminum and bending it is the difficulty in producing an accurate bend. If the 90° bend is off by 1 degree it will cause misalignment for the lead screw and can cause binding.
Here is a great video by Ronald Walters on youtube outlining the issue as well as how he goes about bending the carriage back into shape.
6 – Z-Axis Lead Screw Bent.
The z-axis lead screw being bent is probably the most unfortunate z banding error. If your z-axis lead screw is bent you can try to straighten it if you have the right tools, but you will likely have to replace it entirely.
I couldnt find anywhere that you can just buy a replacement lead screw, but you can buy a dual z-axis lead screw kit and just use the lead screw from the kit and save the other parts as spares.
7 – X and Y Axis Belt Tension
If the x and y-axis belts are not tightened properly it can cause the belt to slip and typically shows as misalignment on the 3D print.
I would not typically diagnose this as z banding because typically it is a very dramatic shift and usually causes the print to fail entirely, but if the belts were to only slightly slip back and forth this could look like ringing or banding on your print outer surfaces.
8 – Minimum Time Per Layer.
This is not a z banding issue as much as it is a material cooling issue. If your material is not allowed enough time to cool between layers it is possible for the printer to extrude hot material on top of filament that is not completely cooled which can cause the lower level to compress and appear as ringing around the part.
There is a setting in most slicers to set the minimum time per layer. If you are still receiving banding on your prints and have already gone through the top items on this list for diagnosing you may want to adjust this setting to rule it out as the issue.
9 – Tall Part Not Supported Properly.
Parts that are excessively tall can sometimes teeter on the build plate if they are not supported properly and this teetering can cause a line/banding effect around the 3D print. To correct this issue you can slow down the print speed, add a brim, and add a sacrifice tower for additional strength.
There are many causes for z banding on an Ender 3 and most can be resolved relatively easily if you know what you are doing and how to diagnose the issue. I am sure there are things that could cause z banding that I left off the list but this should guide you in the right direction well enough to fix most ender 3 z banding issues.