While 3D printing is a hobby that everyone can pick up and learn, there is no denying that it can also become quite technically challenging at times and require a great deal of effort.
Terminology is part of what makes 3D printing complex, as it’s essential to know the terminology correctly to configure and optimize your 3D printer to achieve the best print quality possible.
Today, we will talk about the differences between two widely used terms in the 3D printing space, which are often confused with one another due to how similar they sound.
So, what are the differences between 3D printer feed rate and flow rate?
Flow rate is a multiplier (denoted in percentages) that determines the amount of plastic the printer extrudes at any given moment.
On the other hand, the feed rate is a multiplier (denoted in percentages) the printer uses to calculate the movement speed for all axes, including the E axis.
As you can see, despite sounding similar, flow rate and feed rate are two entirely different values that control separate parts of the printing process.
Next up, we will take a deeper look into what makes these two things different than one another and analyze both of these parameters individually in greater detail.
Feed Rate vs. Flow Rate
Even though they have similar names, feed rate and flow rate are two parameters that are severely different than each other.
In a nutshell, the feed rate value controls the overall speed of the printer, whereas the flow rate value is responsible for the amount of plastic that comes out of the extruder.
While modifying the feed rate will directly impact how quickly the motors of your 3D printer (and, as a result, the axes, including the printhead) move, adjusting the flow rate changes the amount of plastic that comes out of the nozzle during extrusion.
Let’s take a quick look at an example to make things easier to understand:
- Printer 1 – 30 mm/s print speed, 50% feed rate, 110% flow rate.
- Printer 2 – 30 mm/s print speed, 100% feed rate, 100% flow rate.
Assuming these printers, the filaments, and the models they print are identical, Printer 2 would finish printing the model roughly twice as fast as Printer 1 due to the higher feed rate.
On the other hand, the model printed by Printer 1 would be 10 percent heavier (with thicker layers) due to the increased flow rate.
Next up, we will be taking a better look into each of these parameters individually as they both play a significant role in achieving high-quality prints.
What Is Feed Rate in 3D Printing?
The feed rate parameter is one you will encounter in most firmware and slicer software, and its misconfiguration can cause noticeable problems in your prints.
Feed rate is a percentage value multiplier the printer uses to calculate the final values of all movement-related parameters for all the axes of the 3D printer.
Simply put, every movement-related parameter, such as travel speed and print speed, is multiplied by the feed rate value, and the resulting values are taken into effect by the printer.
Let’s take a look at an example:
Assuming a printer is set to a travel speed of 40mm/s, a print speed of 70mm/s, and a feed rate of 70%, what would be the final travel and print speeds?
To find the final values, all we would have to do is to multiply both travel speed and print speed with the feed rate:
Travel speed -> 40 mm/s * 70% = 28 mm/s
Print speed -> 70 mm/s * 70% = 49 mm/s
While you most likely will never have to change the default value of 100%, it’s a practical way to increase or decrease the overall speed of your 3D printer.
What Is Flow Rate (Extrusion Multiplier) in 3D Printing?
Flow rate, also known as extrusion multiplier, is another vital parameter that you can modify in most firmware and slicer software, and once again, configuring it right is highly important.
Flow rate is a percentage value multiplier that determines the amount of plastic the printer extrudes from the nozzle, with 100% being the default value.
Changes in flow rate directly increase or decrease the amount of plastic that comes out of the extruder, essentially changing the layer thicknesses and the overall weight of the print.
The primary use case for the flow rate parameter is to accommodate for differences between different filament materials, as increasing or decreasing the value allows you to compensate for these differences without having to configure a lot of separate parameters.
While you can also use flow rate to solve issues related to over-extruding and under-extruding, we highly recommend ensuring that your extrusion and retraction-related settings are correct before tinkering with the flow rate value.
Are Feed Rate and Print Speed the Same?
A question we notice being asked a lot about in the community is whether feed rate and print speed are the same things or not.
Despite being related to each other, print speed and feed rate are not the same things.
Print speed is a value that controls how quickly the printhead moves (denoted in mm/s) while printing, which essentially is the deciding factor for how fast the printer will print a model.
On the other hand, the feed rate is a multiplier value (denoted in percentages) the printer applies to all movement-related G-codes to calculate effective speed.
For instance, if you set the print speed of your printer to 80mm/s with a feed rate of 100%, the printhead would be moving at 80 millimeters per second during the printing process.
On the other hand, if you set the print speed of your printer to 60mm/s with a feed rate of 50%, you will notice that the printhead moves at 30 millimeters per second instead.
As feed rate affects all movement-related parameters, it’s worth remembering that parameters such as travel speed are also affected.
Feed rate and flow rate are two entirely different parameters despite sounding quite similar and causing a great deal of confusion.
Let’s make a quick recap before we conclude the article:
- Feed rate (%) – Refers to a multiplier that controls speed for all axes, with 100% being the default value.
- Flow rate (Extrusion multiplier) (%) – The rate at which the extruder extrudes the plastic, which you can also think of as the rate the plastic flows. 100% is also the default value for the flow rate.
As you can see, the difference between the two is quite visible, with not a lot of room for confusion once you get used to the terminology.
We hope that it was an enjoyable and informative read, and we will see you next time!
Mike started his 3D printing journey with the Anet A8 when it first came out back in 2017, and has been obsessed with 3D printers ever since. Nowadays, he primarily uses his Ender 3 to print functional parts that make his life more convenient whenever possible.