Calculating E-Steps

At some point, you may find your printer is over or under extruding material.

Having your extruder properly calibrated is essential for getting the best print quality.
There are two steps to calibrating the extruder – tuning your extruder steps/mm value in the firmware, and tuning the extrusion width/extrusion multiplier.

It is important to do it in the correct order.
First, we want to work out how much material is being fed into the hot end and then move on to how the printer is behaving in terms of the plastic actually being pushed out and laid down.
In order to calibrate the steps/mm value, we extrude 100mm of material, then we will measure how much material it has extruded and find the variance (if any)

Measuring

To do this measure out 120mm of filament from where it enters the extruder and mark it with a pen or marker. This will be the reference point. Then, connect your computer to your printer and open up a program that allows you to send individual gcode commands to it (Octoprint, Cura, Pronterface, Simplify 3D, Repetier Host etc).

Heat up your extruder to your regular printing temperature.

Next enter the command  M83 (to set the extruder to relative mode) then  G1 E100 F100 to extrude 100mm of material. This will take 60 seconds until it’s finished.

Once the machine has finished extruding the 100mm, switch off the extruder heater and measure the distance between the point that you marked before we started, and where the plastic enters the extruder (the same point from which you measured the initial 120mm). If this is exactly 20mm, awesome, your extruder steps/mm are perfectly calibrated. If it is more or less than 20mm, then it means that your printer is over or under extruding.

Tuning

In order to calculate what our new steps/mm value will be, we need to know the existing steps/mm value and the under/over extrusion rate. To get the existing steps/mm value, send the command M503. This will print out all the current values saved in your printers EEPROM including all your axis steps/mm values. We’re only interested in the E value – mine was 93. You can use the form below to calculate your new Esteps value:

Calibrating extrusion multiplier (or ‘Flow’)

Now that we have the Esteps calibrated correctly, we need to make sure that the filament being extruded is the same amount as our slicer thinks it is. We do this by printing a single perimeter cube and checking if the width of the walls are the same as our extrusion width.

To begin, accurately measure your filament diameter (i use 1.75mm filament, but some batches are +- 0.05 so be sure to check!) with some digital callipers. Enter this into your slicing software and make sure that your extrusion multiplier is set to 1. Check the Extrusion Width (In CURA this is Line Width)

Load a 25 mm cube into your slicer and set the infill to 0%, perimeters to 1, and top solid layers to 0. Chose 0.15 mm print height.

Print it out and then use calipers to measure the thickness of the walls. Your aim is to get this to be the same as your extrusion width set in your slicer.

Use the form below to calculate your extrusion multiplier based on your measurements.

 

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