What it is
Your 3d printer needs to be calibrated to produce good looking clean prints that stick to the build plate and don't fall apart.
There are many different things that can be calibrated on a 3d printer like the bed level or the e-steps and material flow (how much filament gets extrudes any given time). Even the current going to your extruder can be adjusted.
What I did
I started with bed leveling (as you must do when first installing a printer!). After some time I noticed that my extruder was making "clicking noises" sometimes and read that this could be because I was printing too cold, so I adjusted my nozzle temperature. Then after I changed my extruder and did some prints I checked and adjusted my esteps (they were 7% off). After that I calibrated my flow rate (now 12% less).
How I did it
Let me start with a disclaimer: If you are, for example, adjusting your e-steps and your result is that you have to increase them by 100%: STOP! Most likely there is another, more general, problem with your printer, or your measurement was wrong. So if you're about to make a huge adjustment, please pause and redo the calibration or maybe read about it some more before you damage your printer.
There are different places and methods to calibrate your printer:
Some things are calibrated on the hardware itself, like tightening the bed springs to level your bed. Some are changed in the printer software, for example the e-steps setting. And some are done in the slicer or the printing software such as nozzle temperature and flow rate.
You can print test cubes or other objects to check you calibration.
I did the calibration of my printer step-by-step. That means I looked for things that looked wrong on my prints and then I searched for ways to fix those. For example I noticed blobs (or zits) on my prints, which are little bulges that stick out of the surface of the print because the printer puts too much material in some places. The suggested solutions where to adjust e-steps and flow rate, which made sense for me because I changed the extruder on my printer which could have an effect on the e-steps setting.
If you want a quick start you can follow this article, which describes the basic steps of calibration (checking the printer frame, tightening your belts, etc): https://all3dp.com/2/ender-3-calibration-how-to-calibrate-your-ender-3/
For a complete and thorough calibration, that is assisted by generated gcode files, check this awesome web site: https://teachingtechyt.github.io/calibration.html#intro
I used this to calibrate my flow rate and it was really easy to do. But you can also follow this site step-by-step and do all sorts of calibrations.
What I learned
- there are many ways in which a printer can be calibrated. It's best to do them step-by-step to check if your changes changed your prints for the better.
- Master bed-leveling before you proceed to more complex adjustments. Most faults you see in the first layer or layers of your print are maybe just caused by a badly leveled bed
- Adjusting the nozzle temperature seems underrated (or at least it isn't mentioned much in the calibration context) but it is an important factor in getting good prints (if you extruder is skipping steps and therefore making clicking noises, because the temperature is too low, it will extrude the wrong amount of filament). Keep in mind that the printing temperature of course depends on the material you're using, so on the type or even the brand of filament.
- Print small test objects after an adjustment before you start your 14 hour print!
- You can adjust some things during a print, like bed level (while printing the first layer) and nozzle temperature. You shouldn't however tighten your belts during a print because that will cause an offset that will be visible (yes I did it).