Extrusion Multiplier

TL;DR

A faster and handy way to calculate the extrusion multiplier.

Collection

tools, 3D printing

Motivation

While working with several layer heights between 0.10 and 0.48 mm combined with extrusion widths between 0.2 and 1.6 mm we observed that sometimes the given extrusion width and that what comes out of the printer differs.

You see ugly horizontal stripes on you prints.

Let's get started

What is the Extrusion Multiplier?

The Extrusion Multiplier is a correction value you can set in your slicer configuration, to correct the amount of plastic running through  the nozzle for a given setup. 

Default is just 1.0 and often seen values, are between 0.9 and 1.1.

Think about it as a factor to decrease (lower than 1) or increase (higher than 1) the amount of plastic getting extruded. 

Total flow rate = Flow multiplier in firmware (M221) x Extrusion multiplier

We will now call the extrusion multiplier EM to safe typing.

Do i need it?

It is always a good idea to have a well calibrated printer, so yes you need it and it is easy and stress free to handle that. The only tool you need is your digital caliper and maybe a calculator to add and divide 8 numbers.

What will it do for me?

It helps you to avoid ugly looking uneven top layers and ugly uneven sides / walls / spheres of your prints. Your prints get better with a well calibrated flow rate for your setting and filament. The goal is that if the model has 20mm you get it printed with 20 mm and not with 19.5 or 20.3 mm.

How to use this tool

The goal is to figure out the best EM for a given:

• printer
• nozzle size
• nozzle temperature
• layer height
• print speed
• extrusion wide
• and filament

This list tells us already that the EM is heavily connected to many other settings, this is why sometimes a great printing filament shows less quality while changing only a single parameter like the print speed or temperature. While the EM in prusaslicer is a filament setting and safed as a filament config you will found situations where you need to change that based on other settings.

This tool needs to be printed in VASE mode, so only the “external perimeter” settings are valid for changes to figure out the best value for the multiplier.

You found that setting in:

Print Settings → Advanced → External Perimeter

The EM setting himself is found in:

Filament Settings → Filament → Extrusion multiplier

(in this screenshot the EM is set to 1)

Let's do it!

1. print the octagon
2. measure the 8 sides
3. add the values
4. divide by 8
5. divide the external perimeter wide from your slicer by this value
6. The result is your extrusion multiplier. 

Example

With a 0.4 mm nozzle we chose a external perimeter width of 0.42 mm and a layer height of 0.16 mm, this comes out:

1. 0,40
2. 0,39
3. 0,39
4. 0,40
5. 0,40
6. 0,40
7. 0,40
8. 0,40

That sums up to: 3,18

Divided by 8: 0,3975 so we have an under extrusion!

So we get 0.42 / 0.3975 = 1,056

We have to increase the extrusion multiplier by 1.05 to 1,06 to ensure that the chosen perimeter wide got printed dimension accurate. 

Side effect the single bottom layer octagon is printed with horizontal infill, so we get a little first layer test at the same time.

Lazy Joe

The Lazy Joe model prints a prism, so Lazy Joe has only to add 3 numbers than 8. That reduces the quality of the result because it did not use any stepper combination and direction, but already this is better than the Old School way with 4 numbers.

Old School

The cube which gives you 4 sites, but not a single one who uses more than one stepper at the same time, on a bedslinger. 

Attribution

© yahbluez

Can I sell copies of this?

Yes! Yahbluez shared this project under the GNU GPL v3.0 license. This license allows selling copies, but you must provide proper attribution and use the GPL 3.0 license, as detailed in the GPL v3.0 license itself. You have not the right to use any other licence than GNU GPL 3.0.

Donation

If you like to donate you can buy me a coffee

Filament used

The extrusion multiplier is a filament setting, it belongs to a filament. You will see that different filaments need different extrusion multipliers to print perfect.