How to calibrate the flow of your 3D printer to obtain more exact parts.

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What is Flow in 3D Printing

The Flow is the configuration of the laminating program that allows you to regulate, through software, the amount of filament that will be pushed and purged by the extruder..

This amount of extruded filament will determine if your parts are accurate in its dimensions or not.

Why it is important to calibrate the flow

Calibrating your printer's flow will not only give you more accurate parts, but it will also prevent under-extrusion issues, or walls that don't stick together, (to name a few errors, among others).

Imagine printing parts that don't fit, that don't rotate, that can't be sold because their dimensions don't match what your client requested.

Having your printer perfectly calibrated is priceless. You can become a benchmark in 3D printing, standing out in your field as someone trustworthy, with good quality prints.

How to calibrate the flow of my 3D printer

To calibrate the flow you will need to configure your laminator software to print a calibration cube and take some measurements. From this we can make the corresponding calculations.

Step 1: Open Cura and Configure Parameters.

In Cura you will add a calibration cube by clicking on:

Extensions – Part for calibration – Add a cube

Then you will configure the following parameters:

Quality

• Layer height: 0.2 mm
• Initial layer height: 0.2 mm
• Line width: 0.4mm (must match your nozzle size)

Walls

• Wall thickness: 0.8mm (will correspond to the size of the nozzle you have)
• Wall Line Count: 2

top or bottom

• Upper Layers: 0
• Bottom Layers: 4

Stuffed

Infill density: 0.0 %

Material

• Printing temperature: 205.0 °C
• Build plate temperature: 50.0 °C
• Flow: 100.0 % (Important leave to 100%)

Speed

• Printing speed: 50.0 mm/s
• Wall speed: 25.0 mm/s

Displacement

Enable Retraction: Disabled

Then you go to look for “offset overlaps of wall” and you are going to deactivateIf it does not appear in the list you can search for it in the search bar and disable it.

Step 2 - Print the Cube and Take Measurements

Once the cube is printed, you must take the measurements of all the walls and get an average measurement.

In my case the measurements are: 0.74 mm / 0.71 mm / 0.74 mm / 0.74 mm

Taking the average I have a total of 0.73 mm left

Step 3: Apply the formula

(Wall Thickness / Average Thickness) * 100 = New Flux

In my case it would be: (0.8mm/0.73mm)*100

It would then remain 1,095 * 100 = 109,5

109 % It would be the new flow value to set in Cura (for my case).

Step 4: Set new parameter in Cura and repeat step #2

Now that you have the new flow value, you will need to put it into Cura and run the test again to check that everything is ok.

After entering the new value, print the cube again (now you should activate the retractions) and take the averages again to see the results.

0.80mm/0.77mm/0.80mm/0.80mm

Now your new parameters should give you parts that are more accurate in their measurements. Even so, you should perform all kinds of tests to confirm that this corresponds to reality.

Videos on YouTube

Printing tests

I decided to run some tests to check that the whole process works well, and I printed a cube 20×20 calibration to take measurements.

I also printed one socket test to see if with the new parameters the pieces slide into each other.

In the first test I printed a 20mm XYZ calibration cube, and the results were as follows:

X = 20.09mm Y=20.00mm Z=20.02mm

Which are pretty good I think, since the differences are minimal.

In this test the cylinder entered with a little pressure, but quite well. I have to consider that the seams offer a little resistance, but they can be sanded if necessary, apart from the first layer which may be a little more “crushed” than the rest.

Conclusions:

I think calibrating the flow can help a lot to make the dimensions of your jobs more accurate.. Even so, it seems to me that there are many variants at play, which can produce interference as I mentioned above with the seams.

Calibrate the extruder steps and calibrating the flow by software can be of great importance to have more precise prints.

I also believe that much more testing can be done to improve these approximations using the horizontal expansion, something I will talk about soon.