How to Calibrate Prusa i3 MK3

Calibrating your Prusa i3 MK3 is an important process for setting up the 3D printer. Calibrating your printer the right way helps you achieve the precision you want and prevent certain printing failures that can slow down your work.

The calibration settings for certain parts of your printer can affect factors like print size, precision with angles and edges, straightness, and some other parameters that determine printing accuracy.

There are different parts of your 3D printer that need to be properly calibrated to achieve that quality printing you desire. The essence of this article is to guide you through the whole process of calibrating your Prusa i3 MK3.

The Prusa i3 MK3 3D Printer

The Prusa i3 MK3 Printer is the latest generation of 3D printers from the 3D printer manufacturing brand – Prusa. Although there are very similar variations to the Prusa i3 MK3, the printer became popular for its functionality, simple design, easy maintenance, and upgradability.

Supposing you have one of the earlier versions of Original Prusa i3, you can readily upgrade it to the latest MK3 version and also upgrade it as newer versions are released by the producer.

The Prusa i3 MK3 printer also allows you to use up to 4 printing materials at once, using one hot end. This is not a common feature with currently available printers, making Prusa i3 MK3 a highly functional 3D printer.

The Original Prusa 3D Printer series remains a favorite for many, and the latest version has won several awards and recognitions as the best 3D printer of its caliber for use by hobbyists and professionals.

How to Calibrate Your Prusa i3 MK3 Printer

As we have already highlighted, there are different parts of the Prusa i3 MK3 that require calibration if you must achieve precise results. The parts of a 3D printer that require calibration are:

• The first layer
• The axes (X, Y, and Z)
• Extruder
• Stepper motors
• Fan Speed
• Temperature, etc

Because the processes for calibrating these parts are different, we will examine each one separately and guide you through the process of calibrating it.

Calibrating the First Layer

This is a highly essential but basic calibration procedure you must perform on your Prusa i3 MK3.

First layer calibration helps to create the right distance between the tip of the nozzle and the print surface. The right distance between both parts ensures the extruded substance lies nicely on the print surface or bed.

If this part is not properly calibrated, it can cause issues when the first layer of your printed material falls on the print surface. If the nozzle is too far away from the printing bed, it will prevent the printer material from adhering to the surface and this will ruin your work. On the other hand, if the nozzle is too close to the print bed, it causes the first layer to be squished and this will also ruin your work.

Thankfully, all Original Prusa i3 printers are already calibrated on the first layer. The only reasons why you will need to fine-tune the first layer are when you are using the kit version, which you will have to construct yourself, and when you change certain parts like the nozzle and extruder or update the axes of your printer.

How to Calibrate the First Layer of Your Prusa i3 MK3

There are two ways to fine-tune the first layer calibration:

Setting up the Wizard: The first layer calibration is the last step of the XYZ calibration when you are setting up the printer wizard. The process will automatically fine-tune your first layer calibration.

Using the LCD Menu: The other method for setting up first layer calibration is through the LCD Menu - Calibration - First Layer Calibration. Through this process, you can manually adjust the first layer calibration while letting the printer print a zigzag pattern.

Note that the texture of the sheet layer you are working with will also determine the type of first layer calibration to set. Therefore, there are no precise or recommended calibration values to use. You will usually find the best fit for you through a series of adjustments and test prints.

The Axes or XYZ Calibration

Since you are working with a 3D printer, the positioning of the X, Y, and Z printing components matter a lot as they determine how straight and fit your printed works and ensure all curves, lines, and edges are occurring at the rightful places.

Again, the factory assembled Prusa i3 MK3 printer already comes with an XYZ calibration. You will need to calibrate yourself if you are using the kit version.

You can set up the XYZ calibration through the Wizard, which is a necessary setup after assembling your printer. However, if you skipped the Wizard setup, you can manually adjust the axes calibration through the LCD Menu - Calibration - Wizard.

If you wish to redo the XYZ calibration after already setting up the Wizard, you can also do this by following the LCD Menu - Calibration - XYZ Cal.

Step-by-Step Process to XYZ Calibration

• The calibration process starts with aligning the Z-axis. While the printer does this, ensure that both ends of the X-axis reach the top.
• Next, the printer will ask if you have a steel sheet placed on the heated bed. Remove any steel sheet on the bed and select “No”.
• The printer brings up a prompt for you to confirm if the nozzle is clean. Check your nozzle for dirt and confirm the prompt once sure.
• Place a sheet of paper (this could be the cheat sheet that comes with your new printer) on the heat bed. There is a high probability that your nozzle will at once catch the paper. If this happens, it means the P.I.N.D.A. sensor button is most likely set too high. Press the Reset button, lower the P.I.N.D.A. sensor by 2 to 3 threads, and begin the calibration process again.
• When done, place the steel sheet on the heated bed and confirm the prompt that comes up. Your printer will perform a full 9-point mesh bed leveling and store the measurements in non-volatile memory.

Note: It is important that you do not leave the printer unattended during step 4 or you may end up with a scratched heat bed. Be prompt to ensure that the nozzle is not too close to the cheat sheet.

Calibrating the Extruder

The extruder requires different kinds of calibration, most of which are to be done by advanced users only. If you are new to 3D printing, we recommend that you seek professional help before calibrating any part of your extruder.

You may need to always calibrate your extruder when using a different type of printing filament.

Extrusion Multiplier Calibration

This calibration allows you to fine-tune the extrusion flow rate, that is, how the filament flows out of the nozzle when printing. Issues with over or under extrusion will affect your work and cause visible defects.

If you experience excess extrusion material on the edges of your printed work and too visible printing layers, it means there is over extrusion and you’ll have to decrease the extrusion multiplier. On the other hand, if there are visible gaps between layer lines, it means not enough material is being extruded and you’ll have to increase the extrusion multiplier.

There are two major ways to calibrate the extruder multiplier. One is using the Extrusion Multiplier setting in the PrusaSlicer while the other is using the Flow Rate setting in the printer firmware. You can work with any of them at any time to influence the calibration settings of your extrusion multiplier.

Adjusting any of them will not influence the value of the other. However, any adjustment made to either of them will influence the extrusion multiplier calibration.

Generally,

Total flow rate = Flow Multiplier in firmware × Extrusion Multiplier in PrusaSlicer

There are no ideal values to set for your extrusion multiplier. It would depend on the filament material, color, and other factors. Usually, each filament brand suggests the calibration to work with for your extrusion multiplier.

Calibrating the Linear Advance

The Linear advance of your Prusa i3 MK3 printer is a technology that helps to predict pressure build-up in the extruder during high-speed printing.

This technology works such that it can determine the rate at which filament leaves the extruder. It then uses this prediction to accurately decrease the amount of filament extruded per time as printing decelerates and is gradually brought to a stop. All of these will prevent over extruding during stops and will also prevent excesses at sharp corners.

The K-Value is the parameter that determines how much liner advance affects your prints. Usually, you will have no reason to tamper with the linear advance unless you are working with some exotic filament or you are really up for playing around and experimenting with results.

The linear advance can be a very important parameter for you when you are printing geometric shapes that must be accurate to details. When details matter, you can the K-factor download calibration G-code.

The G-code you download must be specific to your nozzle size, filament material, layer height, printing speed, and PrusaSlicer profile you are working with.

Prusa suggests the following optimal K-values for different kinds of materials and nozzle sizes:

Filament Material	0.4mm Nozzle	0.6mm Nozzle
PLA	0.05	0.04
PETG	0.08	0.04 - 0.05
CPE	0.07	-
PC Blend	0.07	0.04
ASA/ABS	0.04	0.02 - 0.03
HIPS	0.04 (some brands require higher K-values)	0.03 (some brands require higher K-values)
Nylon Taulman	0.08
Nylon FX258	0.1

Note: Calibration techniques like adjusting the extrusion multiplier and liner advance should be done by experienced users alone.

Conclusion

Calibrating your Prusa i3 MK3 printer rightly is important for accuracy in printing. While most of the basic calibrations are preset for Original Prusa i3 MK3 printers, you will need to set the calibrations yourself when working with a kit printer.

Also, certain filament materials or printing processes may require special calibration to achieve more details. We believe this article provides a basic guide for the most important calibration processes. If you are not sure how to go about any, you can always seek professional help or reach out to Prusa’s live chat through their website