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If you are using a non-geared extruder, especially one set up in a Bowden fashion – such as a stock Ender 3, it is likely you will eventually run into extruder motor skips, where you hear a clicking noise coming out of your extruder. When you look at the extruder, you will see the hobbed gear skip and you will either under extrude, have uneven extrusion, or just not extrude anything.
The most common reason for this is the extruder stepper does not have enough torque to overcome the amount of force needed to push filament through your nozzle. This can arise from a few different manners, but this is why extruders with gear ratios are preferred. This mechanical advantage causes the stepper to spin faster (higher E-step number), but it reduces the amount of torque put on the stepper motor.
When using a dual drive, geared extruder, especially one in a direct fashion and not Bowden, you should not have extruder motor skips as an issue - unless you are just printing far too close the to build plate on the first layer or you have a nozzle clog. Regardless if an extruder has dual drive, a proper gear ratio is what definitely helps. We have actually noticed that extruders without a gear ratio above 1:1, but have a dual gear setup, can still have plenty of extruder motor skips. It is the gear ratio that really makes a difference here. Regardless of that, below are a few ways you can eliminate these extruder motor skips.
Is your first layer too close to the build plate?
Getting the proper z-height for your first layer is critical. When your nozzle is too far from the build plate, you can be left with a spaghetti monster or gunked up hotend. When your hotend is too close, you can damage your build plate or nozzle, or just experience extruder motor skips.
When the nozzle is too close, your extruder is trying to push out filament through the nozzle but there is no room for it to escape, so it causes the extruder motor to be unable to push any more material. This will either cause the filament to be stripped or to have the extruder motor skip.
Make sure you give enough room for the filament to lay down properly on the first layer in order to avoid this nuisance.
Slow your prints down.
A common reason your extruder might be making that skipping noise is that you are running your prints too fast. Your nozzle can only push out so much filament depending on its diameter. So, just as with bottlenecking in traffic, you will experience stoppage if you try to push too fast (especially on non-geared extruders and small nozzle diameters).
This can result in grinding of your filament or extruder stepper skipping. The general rule of thumb is to not print faster than 100x the nozzle diameter on non-geared extruders. So if you are using a 0.4mm nozzle, you should limit your print speeds to 40mm/s, and adjust according to your performance - when using the basic extruder that comes on inexpensive machines. This may be slow to some experienced people in the industry, but is the rough estimate we use for printing on a non-geared, stock plastic extruder. Newer fast machines such as those offered by Bambu Lab obviously can run much faster than this.
You can test this out mid print if you have a LCD screen on your machine. Most LCD setups are designed so that when you turn the nob mid print, it will change the feed rate (speed). Newer machines will have something you can touch or go to that is called “Feed Rate” or just under “FR”. If you hear clicking and would like to see if reducing the speed can fix the issue, reduce this feed rate. Go to 90% and lower to see if the skipping is decreasing. You can also just reduce the speed in the slicer and slice a new G-code.
If you still are seeing this problem, you may want to check there is not too much moisture in your filament, as covered in the “Stripped Filament” chapter.
Increase the extrusion temperature
Before attempting this, make sure that your issue isn’t being caused by heat creep or a nozzle clog. If you are experiencing a clog in your barrel due to heat creep, increasing your extrusion temperature will only make the problem worse.
If you are not experiencing any heat creep and the barrel of your machine remains close to room temperature, you can try increasing the extrusion temperature a bit to decrease the chances of your stepper motor skipping. You will normally not want to go outside the recommended print temperatures, but there has been a few times we have had to do this to print properly. This may not work, which is why there are other explanations in this page, but if you print lower than is needed for your filament, it won’t get to the proper viscosity.
This increase in temperature, so long as you are still within the materials accepted extrusion temperature range, will allow more filament to feed through the nozzle at a faster rate.
Be careful when swapping material types
Just as with nozzle clogs and having built up material on the nozzle, you want to be careful when swapping filament types in order to avoid extruder motor skips. When you swap from a higher temp material to a lower temp material, such as from ABS to PLA, you really need to make sure you clear out all of the previous material before continuing. If you just heat your hotend to 210°C and push PLA through, it is likely that there is still some ABS left inside.
The best bet you can do is a cold pull, where you push filament through at the temperature of the filament previously used, then let the hotend cool to 130°C, and pull the filament out. Repeat until all the previous material no longer shows up.
Having any debris in your hotend, or anything that can cause clogs or comes in the way of the filament path, can lead to extruder motor skips.
Too small of a nozzle
The smaller the nozzle you use, the more likely you will experience stepper motor skipping. We have had a near impossible time printing with a 0.25mm nozzle and a non-geared extruder. Minor motor skips led to a print looking as though it was grossly under extruded. E-steps were right on, yet the print looked as though it was under extruded.
This is due to an increased bottlenecking effect at the point of the nozzle.
Loosen the tension on your idler
Most extruder setups have an idler that allows for you to adjust tension – pinching your filament against the hobbed gear or bolt. This tension is necessary to prevent filament grinding and to make sure the proper amount of material is being pushed through the extruder.
While a decent amount of tension is required, you can of course go too far and have this idler be too tight. When too tight you can actually flatten the filament, making it too wide to feed. When material is too fat to too feed you will experience similar issues as you would with Heat Creep, or you may experience stripped filament, but it can also result in the skipping of your extruder motor.
Pinching too tight on a motor that does not have a lot of torque can also cause skipping at the point of contact. While a tight idler allows for good grip on your filament, it is harder for the extruder motor to spin, especially on non-geared setups.
If you notice that the tension on your idler is very tight and you are experiencing skipping of your stepper, try loosening it a bit. Unfortunately the stock plastic crummy extruders that come on inexpensive machines like the Ender 3 do not have a way to adjust this tension. The only way to reduce the idler tension would be to cut the spring, or use a different spring, meaning you would be in jeopardy of making the idler too loose. If you go too loose, you can experience under extrusion as the hobbed gear or bolt will begin to slip on the filament.
Making sure filament path is clear
The first step in making sure your filament path is clear is to check for nozzle clogs and residue in your hotend setup. You will want to make sure the path in your barrel is clear from old material and debris. You can do this by torching out the old plastic in a well-ventilated area.
Aside from old material and debris, we are also talking about the actual pathway that your filament is traveling before being fed through the extruder. If you have a 3D printed carriage that is warped, or one that is not to tolerances, you may have a pathway that does not allow your filament to pass smoothly through it. Any big turns that are required to get your filament to go down your barrel will add to the difficulty involved with feeding material. Resistance at the spool or pathway leading to the extruder will also cause problems.
You may need to print parts (or purchase parts) for a new extruder on your machine with tighter tolerances and a clearer path to the hotend. This is yet another reason you only want to buy hotends from reputable manufacturers that have tight tolerances.
All-metal hotends allow for heating without the need of Teflon tubing. This Teflon tubing can become deformed over the course of a lot of heating, making the filament path not clear.
You should also disassemble your extruder and make sure nothing is blocking that passage either. There could be a piece of broken filament in there that you don’t see that is blocking material from passing smoothly.
Push PTFE tube all the way down
If you are using a stock hotend that isn’t all-metal, you will want to make sure your PTFE tube is pushed all the way down to the heaterblock. If there is a gap between your heaterblock and your tube, this will surly cause at least a minor clog, and then make your extruder skips worse. This obviously will not be an issue on all-metal hotends.
Upgrade to an extruder with a proper gear ratio
We are not fans of extruders that come stock on most inexpensive machines, since they do not have a proper gear ratio. This means that the extruder has a 1:1 ratio, which means it is giving your motor no mechanical advantage. Each turn of the stepper motor has a direct 1:1 relationship with how much your toothed gear turns which pushes out your filament. Even the metal dual drive extruders that some Creality machines have do not have any mechanical advantage, and will still lead to extruder motor skips. Luckily modern printers are starting to come with better extruders stock, but older machines certainly did not.
If you are printing with a very small nozzle, or attempting to print fast, you will almost certainly need an extruder with a gear ratio. Even printing with stock settings and parts can still lead to extruder motor skips on the basic extruder that comes on inexpensive machines.
When you do swap to a geared extruder, you will need to change your E-steps. With a higher gear ratio, it means that your stepper motor has to turn more in order to extrude the same amount of material.
Upgrade hotend if using a very large nozzle diameter
When you are using a very large nozzle diameter, something like 1mm, it is going to be difficult for your material to reach the proper viscosity, unless you print very slowly. This is because you are now pushing a lot more volume of material through the nozzle. If you want to print at decent printing speeds with these larger nozzle diameters, you will want something like the Volcano hotend.
Summary of Fixes and Precautions
• Confirm your first layer isn’t too close to the build plate.
• Slow your prints down (manually change during print with the knob on the
Extruder Motor Skipping (extruder making a clicking noise) 163
LCD screen to see if this fixes the problem).
• Check to see if there is too much moisture in your filament by drying it, or swapping to a new spool.
• Print at a slightly higher extrusion temperature.
• Loosen the tension on the extruder idler.
• Have a clear, straight filament path. Reprint or find a more suitable extruder carriage on Thingiverse if required. Disassemble both the hotend and extruder to see if anything is blocking it from moving.
• Increase the current to your stepper if not at limit and not experiencing overheating. Too little power to your stepper will definitely result in skips.
• Increase nozzle diameter if using smaller than a 0.4mm nozzle and printing without an upgraded extruder.
• Upgrade to an extruder with an increased gear ratio. The crummy stock ones that come on inexpensive machines just don’t get the job done. My favorite is the Hemera, but you can go with competitors such as Bondtech, BIQU, DropEffect, and so many others. Even an old Titan extruder by E3D will drastically reduce any stepper skipping issues, since it has a proper gear ratio.
• If you don’t want to print at a crawl and you are using a larger diameter nozzle, you will likely want to upgrade your hotend. Large nozzle diameters require something like the Volcano hotend or a similar competitor.