Nozzle dragging refers to the heated nozzle or hot end of an FDM 3D printer coming too close to either the build plate or the printed model.
The resultant “dragging” effect will become evident in the quality of the print and/or damage to the build plate and nozzle.
When “nozzle dragging” doesn’t sound particularly pleasant, and it’s certainly not something that a 3D printing enthusiast wants to hear.
Dragging usually occurs when the printer’s settings are incorrect, resulting in the nozzle being too close to the build plate.
This may not be evident on the first few layers of your print but will become so as the print progresses. However, if the misalignment is particularly bad, the nozzle will drag across the build plate and cause damage.
None of this is good for either your printer or your prints.
Even without the obvious potential of damage and poor-quality models, if the nozzle dragging is to a lesser extreme, then the print speed will be reduced.
There are other potential causes which we’ll cover in this article along with ways to avoid and fix the problem.
So, let’s first take a closer look at what nozzle dragging is.
What is Nozzle Dragging in 3D Printing?
As we’ve touched on previously, nozzle dragging can have serious detrimental effects on your printer and your prints.
A 3D printer is a sensitive machine, and even the slightest wrong adjustment can lead to issues.
If your printer is set correctly, then you should achieve decent print quality all the while the settings remain in place. Settings controlled by the computerized side of the printer are something that you can input, and they should stay the same unless changed.
However, the use of your printer can cause physical settings to change over time.
By physical settings, we’re talking about the build plate being level, extruder tension, nozzle distance from the build plate etc.
These can all change slightly just by the continuous movement of the printer in operation and may take time to become apparent.
You can adjust all these settings, and we’ll be looking at that in more detail later.
Nozzle dragging itself is a symptom of an incorrectly configured 3D printer, but there are resultant symptoms you can look out for in your 3D prints.
These could be as obvious as the print itself being caught by the nozzle and dragged, but this would result in an incomplete and failed print. If your print has finished then signs of nozzle dragging can be apparent in the presence of uneven layers, gaps in the layers, and stringing.
Why is there Nozzle Dragging on the 3D Print?
As we’ve mentioned, there can be a few different causes of nozzle dragging in your 3D printer. The most common causes are:
- Incorrect printer calibration: This can include many aspects of the printer’s calibration such as over-extrusion, incorrect z-axis offset, bed leveling, print speed, nozzle, bed temperature etc.
- Dirty or damaged nozzle: A damaged nozzle can lead to clogging or even over-extrusion, which can then in turn lead to dragging.
- Nozzle misalignment: This could be comparable to the incorrect z-axis offset, but could also simply be that the nozzle has been fitted incorrectly. The nozzle would then be either too close to the build plate or at an angle to it.
So, let’s take a look at the first set of issues in a bit more detail.
Over extrusion
This can be caused by the e-steps on your printer setup being incorrectly calibrated.
Without going into too much detail, e-steps control the amount of filament that is being extruded through the hot nozzle.
If you set your printer to extrude e.g. 100 mm of filament, then that’s how much you’d expect it to send through. If, however, it’s extruding say, 110 mm or even more, then that’s over-extrusion.
This will cause the printer to lay down too much filament and cause the nozzle to drag.
The e-steps can be calibrated, and we’ll look at that in a bit more detail shortly.
Incorrect z-axis offset
If your printer has automatic bed leveling, you may find that you need to apply an offset to the z-axis to allow for the correct distance between the nozzle and the print bed.
This may only be a small amount, but you should be able to adjust this on your printer’s controls by 0.01 mm at a time.
Bed leveling
This would be if you were manually leveling the bed each time and the level was incorrect. Again, the nozzle would be too close to the bed and cause dragging.
Print speed
Nozzle dragging can also occur when your printing speed is suboptimal.
On one hand, printing too fast can end in inconsistent extrusion. On the other hand, if the speed is too low, the filament could build up, clog the nozzle and cause dragging.
Nozzle and Bed temperature
Incorrect nozzle temperature can again cause clogging, which then could lead to dragging.
The same with the print bed. If the temperature is too low, then the filament may not stick and will get caught on the nozzle.
How To Prevent Nozzle From Dragging on a 3D Print
As the saying goes; prevention is nine-tenths of the cure.
Obviously, we don’t want to have any nozzle dragging on our 3D prints. But how can we avoid it?
The best way to prevent nozzle dragging and indeed any major problem with your printer is to regularly maintain it.
This means checking that everything is secure and running smoothly and that all parts are in working order.
Clean or replace the nozzle
The easiest problem to diagnose and prevent is a damaged or dirty nozzle.
The best way to solve this is to simply replace it with a new one.
In order to do this properly, the nozzle will need to be heated to a working temperature, so caution should be taken.
- Raise the z-axis either manually or via the controls to near its upper limit.
- Remove the silicone cover (if there is one) and put this to one side. If this looks damaged, then you might consider replacing it as well.
- Using an appropriate socket wrench or spanner, carefully undo the nozzle and place it aside.
- Clean any debris such as dirt and filament from the heated block and ensure that there is no blockage.
- Carefully insert a new nozzle. You will need to do this with your fingers at first, so be careful as they will conduct heat quickly. You should have enough time though to do this without harm.
- Tighten the nozzle with the same tool you removed the old one with.
- Replace the silicone cover and then auto-home the printer.
- Level the print bed either manually or automatically depending on your printer setup.
That may sound basic and something that you do regularly anyway. But it’s also something that needs to be addressed.
The other issue of nozzle misalignment that we mentioned can be rectified similarly.
E-steps calibration
We’ve also mentioned over-extrusion as one of the possible causes of nozzle dragging.
And this too is something that isn’t always noticed until you get an issue with your prints.
The best way to prevent over-extrusion issues is to regularly check the calibration of the printer’s e-steps.
The e-steps control the rate at which your printer extrudes filament and are calibrated to deliver the same amount every time it works. However, external elements and issues such as nozzle clogging and dragging can change the extruder to filament ratio.
To calibrate the e-steps in your printer, you will first need to see if it’s under or over-extruding.
- Measure from the point where the filament enters the extruder and make a mark on the filament 100 mm from that point. It’s also worth making a couple of extra marks at 110 and 120 mm.
- Heat the printer to a working temperature.
- Set the printer to extrude 100 mm of filament and wait for it to finish.
- Look at your marks and see how much has actually been extruded. If it’s bang on 100 mm, then your e-steps are correctly calibrated.
- If there is a gap between the 100 mm mark and the extruder then it’s under-extruding and if it’s gone past that mark then it’s over-extruding.
- Measure the difference and make a note. For this example (and ease of calculation) we’ll assume it’s over-extruded and sent through 110 mm.
- Every printer will have its own default e-step setting, but for reference we’ll use a Creality Ender 3 which has a default of 95.0. You can check your own printer’s settings by finding the e-step figure in the printer’s control menu.
- We then need to calculate the new e-step using the following formula: Expected amount of filament x Current e-step setting ÷ Actual amount extruded
- Using the figures we’ve already got then this will give us: 100 x 95.0 ÷ 120 = 79.17
- Enter the figure of 79.17 as the new e-step figure into your printer.
This should then solve the over-extrusion issue and the printer will then extrude the correct amount.
This is quite an extreme example of over-extrusion, and it may be only a few millimeters out. But the formula works in the same way.
You would also use this formula for under-extrusion issues and re-calibrate in the same way.
Optimal temperature
The wrong calibrated temperature (either low) can also be a reason behind dragging.
If e.g the temperature is too low, the filament is cooling down too fast and is not extruded properly.
The goal in this case is to find the right temperature balance between your hotbed, extruder and required filament temperature.
You can find various calibration tests for free to find the ideal temperature settings for you.
These are just some of the potential issues that can cause nozzle dragging but can be set correctly to avoid the issue in the first place.
The other preventative issues we’ve mentioned are fairly self-explanatory. The basic message here is to keep your printer properly maintained.
When to Seek Professional Help
Of course, not every issue is something that you could fix yourself.
No matter what your experience of 3D printers is and how good you are at fixing them. There could always come a time when you’re at a loss for how to proceed.
If its help with one or more of the issues that we’ve looked at, then there are always online forums and Facebook pages where you might be able to find assistance.
However, nozzle dragging can cause severe damage to your printer if say your printer is unattended for an overnight print.
You may come down to your workspace in the morning and find all sorts of carnage has befallen your precious machine.
Or, on a slightly less dramatic note, you simply can’t find the cause of the nozzle dragging. This may be the point when you look to find a professional 3D printer repair service.
Finding the right one may depend on where you are in the world and how well-served the art of 3D printer repair is in your area.
Obviously, the best place to look first would be online, and you then will hopefully be able to find what you need.
It would be difficult to recommend or even mention any specific repair services, given that readers of this article could be anywhere in the world.
However, it would be fair to say that most countries that have a good presence in the 3D printing community are likely to have professional repair services.
Considerations
There are of course a few things that you need to take into consideration though when looking for professional help with your 3D printer.
- Customer experience: Check for any online or social media reviews before committing to using the service.
- Cost: If you’re doing the transaction online, then get a quote first. There may be a charge just to look at your printer, so take that into account as well. If you’re able to find a local repair shop and can take your printer there, then this may be much easier.
- Shipping, insurance, etc: If you’re asked to ship the printer to the repairer, then factor that cost into the overall repair bill. It’s also worth looking at insurance for both damage caused during the shipping and against loss or non-return of your printer.
- Other considerations: Work out whether sending your printer away to be repaired or even taking it to a store is actually worth it. You may end up paying almost as much as your printer cost in the first place just to have it repaired.
Conclusion
We’ve looked at nozzle dragging, and you can see that it’s something that you should avoid if possible.
However, should the fateful day come when it does happen to you, then we’ve discussed ways to solve the problem.
As we’ve said, though, prevention is the best way to avoid nozzle dragging.
Hopefully, this article has provided you with some guidance on that. Remember that there is always someone out there in the 3D printing community that has had the same issue. So don’t be afraid to ask for help if you need it.