3D printers need, as all machines, a regular maintenance to work as expected.
They usually come well tuned, so we almost have to plug and print. This work fine for first time prints, but it is not the real workflow. We need to learn how to properly calibrate our machines, in order to keep good prints as time passes.
Now we are going to learn how to calibrate the extruder of our 3D printer.
Calibrating the extruder
First of all, we need to know what are we going to adjust. When we talk about “calibrating the extruder”, we talk about:
- Calibrate e-steps: It is a must to check that the machine feeds the right amount of plastic.
- Calibrate flow: As it prints, It needed to check that the output is the right cuantity – but too much (overextrusion) or less (underextrusion).
- Temperature: It is a right way to know what temperature works better for current filament.
- Speed: Let’s ckeck if there’s any kind of problem with different velocities.
- Retraction: We need to understand how does our machine retracts the filament, because it can cause problems derived from ooze plastic.
E-steps is most basic feature. It should work for most filaments, but It is recommended to check if It works the same for different materials (PLA, ABS, TPU…).
Flow, temperature, speed and retraction are more specific, and we should check them for each filament brand and color. I say “we should” because in the practice, most colors from same manufacturer works pretty similar. We could do that before start working for very first time, or regulary if we have bought new filament spool and want to check.
It is also a good idea to check them before doing an important print, if we want to be sure of which parameters will work better for the project.
Extruder is a simple step engine with some gears and a heater that melts filament and place it in right X-Y-Z coords. Based on this, we have to achieve that it feed the right amount of filament.
If we tell the extruder to extrude 40mm it has to extrude 40mm, not 42 nor 38mm.
So first of all we have to measure 40mm from the extruder imput. Make a line using a pen.
After that, we preheat the extruder to 200ºC aprox, and then
(if you own Ender machines like me) go to Prepare -> Move axis -> Move 1mm-> Extruder and set it to 40mm.
Note: In case you are controlling your printer from PC via USB, you can connect your printer to a slicer like Repetier-Host which allows you to manually control the machine. You should enter a “G1 E40 F100“. It would extrude 40mm in 24 seconds by 100mm/min.
Now just wait and see how filament feeds until it stop. Next, if you can still see the line that you marked, measure again how much filament is left. You will be under extruding. If you can’t see the line, you might be over extruding.
Write on a sheet of paper the measure, and repeat the process for three or four times. The avarage will give you a better image of how does your machine extrude.
In my case, I was getting 38, 36, 38, 37mm when I put 40mm. Mine was under extruding.
Following these numbers, the avarage was 37,25mm instead of 40.
In order to know what are right e-steps, I checked actual manufacturer config. 98,7 were stock ones. This means that to calculate what should be its right e-steps:
Desired distance / measured distance * Current e-steps = new e-steps
In my case: 40/37,25 * 98,7 = 105,98
Modifying e-steps setting to the printer
Depending on your printer, you will have easy access to the source files via Arduino (open source machines) or you might have it a little bit more complicated to in more commercial ones.
For more commercial ones like Ender 3 from Creality, the easiest way to implement this change is directly writing a Start G-Code script in our slicer, where we specify our new e-step value and it will be written in all our .gcode files that we export.
M92 is the command that we will use for calibrating e-steps.
M92to set the steps-per-unit for one or more axes. This setting affects how many steps will be done for each unit of movement. Units will be in steps/mm unless inch mode is set with
In our case, the code to be written is: ” M92 E105.98 ;”
Saving this, we will have adjusted the steps of our extruder for further prints.