To get the best performance out of your 3D FDM printer, you’ll need to calibrate the extruder. By doing so, you’ll ensure that the amount of filament coming from the nozzle is in the "Goldilocks zone"—not too much and not too little.

This article will show you how easy it is to improve your prints by completing this necessary calibration.

The Importance of Extruder Calibration

The Anycubic Vyper dual-gear-extruder

If you’ve ever had trouble getting your first layer to stick or blobby prints constantly plague you, then extruder calibration could be the likely culprit. Too little filament through the extruder will cause layers to delaminate and lead to poor print adhesion on the build plate. Too much filament through the extruder could result in warped or stringy final prints.

On the other hand, a properly calibrated extruder will deliver just the right amount of filament to each layer of your print. That means your first layer will stick to the build plate correctly, and your finished prints will come out looking superb.

Extruder calibration is an easy way to get higher quality from your 3D printer, and it's easy to perform with the right tools. And extruder calibration works for both Bowden tube and direct-drive extruders. Additionally, you should perform this process periodically to ensure your printer is working optimally. Doing so is especially important if you begin to notice signs of under or over-extrusion.

What You’ll Need

The Anycubic Vyper printer

To perform this calibration, you’ll need a few things:

  • An FDM 3D printer
  • Some filament
  • A vernier caliper
  • A felt-tip marker that is a different color than your filament
  • A computer running slicer software

Step 1: Loading Filament

The first step in this process is to load filament into your 3D printer. Consult your owner’s manual on the proper procedure for completing this step. In most cases, you’ll heat the nozzle and then feed the filament into the extruder.

Once this filament starts to ooze out of the nozzle, then you know your printer is ready to begin calibration. Make sure you remove any previous material stuck to the end of the nozzle as well. You want your nozzle to be as clean as possible before beginning this process. Also, it's important that the nozzle is heated for everything to work.

Step 2: Connect Your Printer to Your Computer

M83 command to put printer into relative mode

Next, you’ll connect your computer to your 3D printer. For most printers, you can do this via a USB connection. Or, if you have Octoprint set up (which is well worth doing), you can use the web interface here. You’ll also be sending several lines of G-code and monitoring the output at the terminal level, so it is crucial that you have this capability.

Once you’ve hooked up your computer, you’ll need to put the printer into Relative Mode. Do so by sending an M83 command to the printer via the terminal.

Related: 3D Printer Mistakes You Should Avoid to Get a Better Print

Step 3: Marking and Measuring Filament for Extrusion

Measuring 120mm of filament from the runout sensor

Next, we’ll need to measure and mark the filament we intend to extrude. For this demonstration, you should set your vernier caliper to 120mm. Then, measure 120mm of filament from the inlet on the extruder or the filament runout sensor. You’ll need to use your felt-tip pen to make a small mark on the filament at this measurement. This mark must be both visible and accurate so take your time here.

Marking filament at 120 mm

Step 4: Extruding 100mm of Filament

Once you’ve set your mark, you’ll use the terminal to send 100mm of filament through the hot end. To do so, enter the command G1 E100 F100. The printer should begin to extrude what it believes to be 100mm of filament through the nozzle. This process will take about a minute. When the process completes, you can move on to the next step.

Step 5: Measuring a Second Time

Measuring 20 mm of filament after the 100 mm extrusion completed

Using your vernier caliper, measure the distance between the inlet on the extruder or runout sensor and your mark. The length here should be somewhere around 20mm. If your measurement is exactly 20mm, no additional calibration is needed, and you can go back to printing as usual.

But, if this distance is more than 20mm, then your printer is under-extruding. If it is less than 20mm, then your printer is over-extruding. Don’t worry, though. You’ll adjust the extruder’s steps per millimeter value to dial in the extruder perfectly in the next step.

Step 6: Calculating Correct Steps Per Millimeter Values

E-Value Line m92 highlighted

To adjust the extruder, you’ll need to do a few calculations. First, you’ll need to find the current steps/mm value of your printer. To determine this value, send command M503 to your printer via the terminal.

Doing so should return a few lines of code. Find the line labeled echo: M92. At the end of this line will be an E-value. This value indicates your current steps/mm.

Next, you’ll need to find the physical steps/mm value. You’ll calculate this value by subtracting your post-extrusion measurement from 120. Let’s say your second measurement was 22mm, for example. In this case, you’d subtract 22mm from 120mm, which would give you 98mm of filament extruded.

Then you’ll need to calculate how many steps your extruder took to get to that measurement of filament. To perform this calculation, use the number you recorded for the current E-value multiplied by 100, which is the amount of filament your printer should have extruded.

If your extruder’s E-value were 417.30, for example, then you’d multiply that number by 100, which would equal 41,730 steps to get to 98mm of filament extruded.

The final calculation needed is the correct number of steps to extrude 100mm of filament. To get this value, you’ll divide the number of extruder steps from the last equation by the actual mm of filament extruded in the previous equation.

For the example, you’d divide 41,730 by 98mm, which equals 425.81 steps/mm. This steps/mm value is the number you’ll be setting your E-value to in the next step.

Formulas:

  • 120 - [distance from mark to extruder or runout sensor] = [actual mm measurement of filament extruded]
  • [E-value] x 100 = [number of steps to extrude actual mm measurement]
  • [number of steps to extrude actual mm measurement] / [actual mm measurement of filament extruded] = [correct steps/ mm]

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Step 7: Setting the Proper Steps Per Millimeter

M92 E417.3 command to set correct steps

The final step in calibration is to set the E-value to the correct steps/mm. To do this, you’ll send the command M92 Exxx.x to your printer. Here, you'll substitute the x’s for the proper steps/mm value from the last calculation.

For the example, you’d type M92 E425.8 into the terminal command line and then hit enter. You’d then save this value by sending an M500 command to your printer. At this point, it’s best to reboot the printer so that you can double-check all of your settings.

Step 8: Test and Recheck

Vernier caliper set at 120 mm for measuring filament

Once you’ve rebooted your printer, you should perform the measurement, marking, and calculation steps a second time. This time your printer should extrude exactly 100mm of filament, and you should have precisely 20mm between your mark and the extruder.

If this isn’t the case, you can enter a new E-value based on your new calculations. Then retest until you’ve gotten calibration perfect.

Related: Everything You Need to Know About 3D Printing

Enjoy Your Calibrated Extruder

3D printers are incredible machines. But to get the most of your 3D printer, you need to make sure that you calibrate your extruder correctly. This task isn’t challenging to complete, but it does take a little effort to perfect everything. By following this guide, you can ensure that you’ll avoid extrusion issues, and your 3D prints will come out looking amazing.