The extruder in an FDM 3D printer is the business end of things and what makes your raw filament printable.
Calibrating the extruder to correctly produce the right amount of filament at the right speed and temperature is essential to a successful 3D print.
This calibration is probably the most important setting on your printer and can be the difference between the success and failure of your print.
In this article, we’ll be looking at the best ways to get that calibration right and to help you on the way to producing quality prints every time.
We’ll be looking at what you need to get you started, how to go about the calibration process itself, and some tips and tricks to make the process a bit easier.
Once you have your extruder calibrated perfectly, you’ll notice the improvement in your prints, but what are the signs that the calibration is incorrect?
Well, there are a few things that you can look out for that may be an indication of poor extruder calibration, but these are usually caused by two basic things.
- Over Extrusion: The amount of filament that is being extruded exceeds what you are expecting. For instance, for every 100 mm of raw filament that is supposed to go through the extruder, it’s actually feeding through 110 mm. This can lead to “blobs” and lumps in your model and even nozzle clogging.
- Under extrusion: Unsurprisingly, the exact opposite is occurring. Under extrusion will cause the layers to be very thin and the model will most likely crumble in your hands. This can also lead to nozzle clogging as the filament won’t get through to the nozzle to allow it to heat properly.
The calibration setting we’re talking about here is most commonly known as the E-Steps and is literally the number of steps your extruder needs to take to extrude the correct amount of filament.
Let’s then take a look at how we go about calculating and setting your printer’s E-Steps.
Preparation and equipment
In order to calibrate the extruder correctly, you first need to determine what the current E-Steps setting is for your printer.
This can be found in the settings in your printer’s controls, and this can be in various locations dependent on your printer model.
So, for ease of explanation, let’s use the Creality Ender 3 Pro to show you where to find the current E-Steps setting.
Firstly, enter the main menu and scroll down to Control and then Filament.
This will give you a line E in mm² and will show as being Off so change this to On and go back a stage.
You’ll see that some extra options have appeared in the menu, so scroll down to where it says step/mm.
This will bring up several figures but the one we’re interested is at the bottom and will show E-steps/mm: 93.00 which is the default setting for the Ender 3 Pro but may be different on other printers.
Make a note of this figure, and then you can leave your printer for the time being.
Now you have that as your starting figure, you’ll need a few other things before you go on to the next stage.
These will be a pen and paper, a calculator, a ruler or ideally a set of measuring calipers, a Sharpie, or other permanent marker and of course some filament.
So, let’s now go through the next stages of calibration.
Extruder Calibration Guide
So we’ve found out where to find the current E-Step figure and gathered our equipment together.
The next thing that’s needed is to see if that figure is correct or if we need to change it at all.
Don’t be fooled into thinking that the figure of 93.00 mm is obviously wrong, as the E-Step doesn’t have to be bang on 100 mm for it to extrude that amount.
Let’s now go through how to calculate the E-Steps and reset them if necessary.
Prepare the printer
We’ll assume you’re using PLA, so set your printer to the correct nozzle and bed temperatures that are appropriate for the one you’re using.
Next, feed the filament by hand as you would if you were preparing it for printing and ensure that it comes through the nozzle easily.
To make things easy for yourself, it’s a good idea to set the Z-axis to about 150 mm and the X-axis to around 120 mm, so they’re pretty much centered.
You can move the Y-axis if you want, but it’s not essential.
Measure the filament
The purpose of this test is to see if exactly 100 mm of filament is being extruded. So you need to measure that distance from the point where the filament enters the extruder and make a mark with your Sharpie.
Also, make at least two marks at 5 mm increments on either side of the 100 mm mark, as this will make things a bit easier later on.
Set the extruder
You need to send 100 mm of filament through the extruder so, using the printer controls, set it to do just that and wait for the process to finish.
Ideally your printer will have extruded 100 mm of filament and all is good, but we’ll assume that it’s over extruded, and you’ll then have seen your 100 mm pen mark disappear without trace.
Let’s make the next bit easy and say that your printer has in fact extruded 105.00 mm.
Note this down along with the original figure of 93.00.
Calculate the E-Steps
This is a set formula whereby you take the current E-Step figure, multiply it by 100 and then divide by the actual amount of extruded filament measured.
This then gives you the following:
- 93.00 x 100 = 9300
- 9300 ÷ 105 = 88.57
You now have a new E-Step figure of 88.57 mm, which is what you need to reset on your printer.
One piece of advice regarding the Ender 3 Pro and possibly other similar printers is that, if you turn it off, the E-Step setting will reset back to the default.
So, just remember to make a note of the calculated setting and re-enter it if necessary.
This should then give you the correct extrusion rate of 100 mm and will have solved all your problems.
But wait, there are a few other things that you need to do to make sure everything is in order.
Tips and tricks
We’ve seen how you can calculate and set the E-Steps to provide correct extruder calibration and have done this in a particular way based on an example 3D printer.
You can of course connect your printer to a laptop to view the E-Steps if you wish using software such as Pronterface, but you’ll still need to go through the same measuring/calculating process anyway.
You may also find that extruder calibration is something that you have to do regularly, and that’s not uncommon. But there are a few things you can do to try and avoid having to do it too regularly.
- Regular maintenance: Ensuring that your extruder is working smoothly and cleanly will help to maintain the correct calibration.
- Print speed and retraction: Check that you’re not setting too high a print speed than your extruder can cope with, as this will lead to calibration problems much sooner. Also, the same should be applied to the retraction speed for the same reason.
- Temperature: Make sure the working temperature is appropriate for the filament you’re using, as this can cause the extruder to over work and then over or under extrude. Use temperature tower to find the right temperature settings for your printer and filament.
- Bed levelling: This may sound unlikely, but anything that can cause the filament to be extruded at the incorrect rate will have a knock-on effect for the extruder.
It is possible to calculate and calibrate your extruder by using printable tools such as one of the tools in the image above.
This makes the process of measuring the filament extrusion much easier.
Other useful ways of doing this could be to use a drinking straw or a length of Bowden tube and place it over the filament before it enters the extruder.
In order to test the calibration properly, you really need to print something rather than just measure the length of the extruded filament.
You can dive straight in and print a model, but a good idea is to print a calibration cube.
These are mainly designed to show any misalignment of the X, Y, and Z axis. This cube also give you a good indication of print quality and whether you’re over or under-extruding.
The method we’ve gone through here is fairly basic and only describes one make of printer.
There could be different processes you need to go through with your printer in order to set it up and, as we’ve discussed, you may need to use a laptop or PC to establish your E-Steps and rest them.
You can also use printable tools to help with the calibration, and it’s always advisable to carry out tests as you go.
Hopefully then this article will have given you a brief overview of how to calibrate your extruder and will ensure that your prints are perfect every time.