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Extrusion Multiplier Vs. Flow Rate: Differences Explained

As you experiment with different slicers, you'll encounter these terms when configuring print settings. So, what's the difference between extrusion multiplier and flow rate?

Written by:
Ben
Last updated:
11/16/2023

If you’re just starting out in the world of 3D printing, you may have come across the terms extrusion multiplier and flow rate. As you experiment with different slicers, you’ll encounter these terms when configuring print settings. So, what’s the difference between extrusion multiplier and flow rate?

Strictly speaking, there’s no difference between extrusion multiplier and flow rate. The two terms mean the same thing and are often used interchangeably. Generally, some slicers use the term extrusion multiplier while others use flow rate.

Read on for more insights into the meaning of the terms extrusion multiplier and flow rate and tips on choosing the right setting for your 3D printer to get quality prints.

What Is the Extrusion Multiplier?

An extrusion multiplier is a number that you enter into your slicing software to control the flow rate of filament. This number tells the printer how many times to extrude the filament per unit length.

For example, if you set the extrusion multiplier to 1, the printer will extrude the filament once for every 1 mm of movement. If you set the extrusion multiplier to 0.9, the printer will extrude the filament once for every 0.9mm of movement.

What Is Flow Rate?

Flow rate is a percentage you enter into your slicing software to control filament flow. This number tells the printer how much of the filament’s cross-sectional area should be extruded per unit time.

For example, if you set the flow rate to 90%, the printer will extrude the filament so that 90% of the filament’s cross-sectional area is extruded per unit time.

The Bottom Line: Flow rate and extrusion multiplier refer to a number that controls filament flow. The main difference is that flow rate is expressed as a percentage, while extrusion multiplier is a whole number. Nonetheless, as this discussion thread on Reddit highlights, they mean the same thing.

How To Choose the Right Extrusion Multiplier/Flow Rate

Now that you know the difference between extrusion multiplier and flow rate, how do you choose the right setting for your 3D printer?

Here are a few guidelines to help you get the best results:

Experiment With Different Settings

It’s essential to experiment with different settings to find the one that gives you the best print quality. Don’t be afraid to try different values for extrusion multiplier and flow rate until you find the ones that work best for your printer.

Specifically, here are the steps you should take to find the correct values for your printer:

  1. Choose a model to print.
  2. Print the model using the default settings in your slicing software. This is usually 1.0 or 100%.
  3. If you’re not satisfied with the results, increase or decrease the flow rate by 0.03-0.05 (3-5%) increments to see if it makes a difference in print quality.
  4. Repeat steps 2 and 3 until you find the flow rate that gives you the best results.

Here’s a brief tutorial on how to calibrate your 3D printer’s flow rate/extrusion multiplier:

https://www.youtube.com/watch?v=WWAVfkNmzxs

Pay Attention to Filament Type

Not all filaments are created equal. Some filaments perform better at higher flow rates, while others perform better at lower flow rates. So, it’s essential to experiment with different flow rates to find the one that gives you the best results with your filament type.

Here are a few guidelines that may come in handy in this case:

  • If you’re using a filament with a low melting point, such as PLA or ABS, you may need to set the extrusion multiplier or flow rate at 0.9-1.0 (90-100%) to maintain a steady flow of filament.
  • If you’re using a high-temperature filament, such as nylon or polycarbonate, you may need to set the extrusion multiplier or flow rate at 1.0 -1.05 (100-105%) to avoid under-extrusion.

Watch for Under- or Over-Extrusion:

Under-extrusion and over-extrusion are two of the most common problems when using a 3D printer.

Under-extrusion is when not enough filament is extruded, which can cause prints to come out incomplete or with poor surface quality. On the other hand, over-extrusion is when too much filament is extruded, which can cause prints to come out lumpy or with excessive stringing.

The best way to avoid these problems is to watch your printer’s extrusion rate and make sure it’s within the recommended range for your filament type. You can do this by checking your printer’s LCD screen or by using a webcam to watch the print process in real-time.

Tips for Getting the Best Results From Your 3D Printer

Now that you know the basics of choosing the ideal extrusion multiplier and flow rate, here are a few tips to help you get the best results from your 3D printer:

  • Keep your filament clean and free of debris. Also, ensure you use quality filament filters to avoid clogging the nozzle.
  • Properly calibrate your printer to ensure the extruder is feeding the filament into the hot end at the correct speed. If possible, use a filament with the same diameter as the nozzle.
  • Ensure your print bed is level and clean and that the printer is properly calibrated to ensure the print head is at the correct height. Using a heated print bed can also help improve the quality of your prints.
  • Check the nozzle for clogs and clean it if necessary. In this case, I recommend using this REPTOR 3D Printer Nozzle Cleaning Kit from Amazon.com. It comes with quality tools to help clean clogged nozzles quickly and easily, such as stainless steel needless for quick access to hard-to-reach areas.
  • Ensure your printer’s hot end is calibrated, and always use the correct temperature for your filament type. The following table summarizes the recommended starter temperatures for different filaments:
Filament TypeRecommended Temperature
ABS446 – 464°F (230 – 240°C)
PLA419 – 455°F (215 – 235°C)
Nylon464 – 536°F (240 – 280°C)
Polycarbonate482 – 608°F (250 – 320°C)
PETG446 – 482°F (230 – 250°C)
Source: Filaments.Ca

Conclusion

In summary, there are no differences between extrusion multiplier and flow rate in 3D printing. The two terms mean the same thing, only their presentation varies.

Nonetheless, choosing the right extrusion multiplier or flow rate can be a bit tricky, but it’s worth taking the time to experiment until you find the settings that work best for your printer and filament type. By following the tips in this article, you’ll be able to produce high-quality prints with ease. Good luck printing!

Written by:
Ben
Last updated:
11/16/2023

About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.