5. Preflight check

Relevant for:

MMU3

Last updated a month ago

Difficulty

Easy

Steps

Available languages

Step 1 Filament preparation

Note: The following instructions apply to all printers supporting MMU3. You may see images with different printers or parts, but this won't affect the procedure. Any model-specific differences will be clearly noted.

Your assembled MK4S with MMU3 has been calibrated and tested in our factory. However, a few easy checks are still required.

We can now move on to loading the filaments in and printing the test object! But first;

⬢Please prepare at least five different PLA filaments and cut off the ends to form a round sharp tip on each - as seen in the picture.

⬢The filaments must have a sharp tip in order to load properly into the MMU as well as into the printer. If the tip is deformed, bent or larger in diameter, it won't load properly.

⬢Inspect the last 40cm (15") of each filament. Make sure there are no dents in it. Sometimes, if filament got jammed before, the pulley wheel makes an indent in it. This part of the filament can no longer be grabbed and moved by the MMU unit and must be cut off.

⬢If the filament end is bent, straighten it. It must be perfectly straight.

Use only high-quality filament with guaranteed low diameter deviation. In case you have filament loading / unloading issues in the future, re-visit this step as well. Make sure the filament is dried up. Moisture-sensitive filaments can be problematic during the MMU operation.

Step 2 Suggested filament layout

⬢Lay down the five filaments onto the spool holders. Make sure the spools do not interfere one with another.

Filament positions are labeled 1,2,3,4,5 from the left to right, from the user's point of view.

⬢Adjust each spool holder so that the spool fits the rollers correctly.

⬢Verify the spool is able to rotate freely and nothing interferes.

⬢Take the cassette for Filament 1 out of the buffer.

Step 3 Loading a filament through the buffer

⬢Insert the tip of the filament 1 into the bottom PTFE tube attached to the spoolholder.

⬢Keep pushing the filament into the PTFE tube until it appears in the corresponding buffer cassette.

⬢Take the tip and insert it through the cassette into the other PTFE tube, which goes into the MMU unit.

Step 4 Preloading filaments to MMU

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On the printer, go to the Filament -> Preload to MMU

⬢Select Filament slot 1. The MMU unit will engage the idler into the first position and start rotating the pulley until the filament is loaded in.

⬢Keep pushing the corresponding filament end into the PTFE tube from the buffer into the MMU, until you feel the filament being pulled in.

Remember, the filament tip must be straight and sharp in order to load it properly.

⬢Repeat the same process until you load all five filaments.

Step 5 Closing the buffer

⬢After a given filament is successfully loaded into the MMU, return its cassette back into the buffer.

⬢Repeat the same process for the other filament positions, until you successfully load all five filaments into the MMU.

Step 6 Pro tip: Loading using the buttons.

⬢You can also load a filament into the MMU using the buttons on the unit. Next time you load a filament, use the method you prefer. Either from the LCD menu, or using the physical buttons.

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While the MMU is idle; (indicated by ALL LED lights OFF)

⬢The middle button starts or aborts the filament loading to MMU.

⬢The side buttons move the selector left and right to switch filament positions.

⬢Use the side buttons to move the selector onto the desired filament position indicated by the selector being aligned with one of the lines on the label-plate.

⬢The ongoing loading process is indicated by a blinking green LED light for the respective filament position.

⬢Stable green LED light means the given filament is loaded to extruder.

Note, after you issue a command to the MMU unit, wait and let it finish the operation. Don't rush. Don't play around with the printer in the meanwhile. Let it finish first if the MMU unit does something (homing, loading, unloading).

Step 7 Loading test (part 1)

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Go to the Control > Loading test

⬢Select the filament type to preheat (PLA)

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Test all the filaments from 1 to 5 manually, if "Test All" item is unavailable on your firmware version.

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The MMU unit will now load and then unload all five filaments to see if all work correctly.

Step 8 Loading test (part 2)

⬢On the MK4S printer, you can check the filament sensor's status in the "footer" area of the LCD screen to see if it's detecting the filament correctly.

Step 9 Printing a test object

We need to print a test object to verify that everything works correctly. Don’t worry, it will be a quick print.

⬢Visit MMU3 Test objects on Printables.com

⬢In the Print files section, download a G-code file pre-sliced for your printer model.

⬢Save the .gcode or .bgcode file onto a storage media and print the test object.

Step 10 Tools Mapping

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Tools Mapping screen on MK4S allows you to reassign the extruders with the specified color to another one as needed.

⬢On the left side, you'll see a list of the required materials and their colors, as specified in the G-code file.

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On the right side, you'll find a list of materials currently available on the printer, that will be used to print the object.

For example, if the G-code requires orange filament in the first position, but you have orange loaded in the fifth position, select the first position on the left menu and then assign it to the fifth position on the right.

Double-tap the filament positions or use the encoder to select the filament number.

Step 11 Printable 3D models

⬢To further test your new MMU3, have a look at MMU3 Test Objects Collection on Printables.

We recommend printing the cute sheep, which has been the MMU mascot since the beginning.

Step 12 Print & Follow the Handbook

Please read the 3D Printing Handbook dedicated to your printer and follow the instructions to set up and use the printer properly. The latest version is always available at help.prusa3d.com.

Read the Disclaimer and Safety instructions chapters.

⬢Start the print and wait until it finishes. In the meantime you can take a look at the printed Handbook.

All the information regarding calibration, how to organise the printer, buffer, spools, or troubleshooting tips are all in the printed or online 3D Printing Handbook for MMU3.

To download the Handbook or if you encounter any issues, please visit our knowledge base at: http://help.prusa3d.com/en/tag/mmu3/

⬢If you are having any issues while printing, follow the on-screen instructions or visit the link from the LCD screen.

Step 13 G-code preparation / Custom model preparation

⬢Already printed all the bundled multi-material models from us as well as those seen at http://Printables.com? Time to print your own designs!

⬢The simpliest way of making a single-body object colorful is the MMU Painting function in PrusaSlicer.

⬢Basic steps for the manual method are described in our G-code preparation for multi material print section.

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For printing logos or text labels, you might also find the automatic color change at a given layer height useful. Simply, slice an object, select a certain layer height, click the small orange "+" icon next to the height marker and select the desired MMU filament position (Extruder number).

Step 14 Making your own Multi-material models

⬢If you have designed a model with multiple bodies, you may find the Exporting model from Fusion 360 guide useful.

⬢If you are designing a single-body model, part of which should be MMU-Painted, make sure there is a sharp line surrounding each distinct part so that you can use the MMU Painting's Smart-fill function later on in PrusaSlicer.

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If you have an intricate STL file that can't be MMU-Painted easily, you can try the more sophisticated way of Splitting STL with single compact part or Splitting STL into multiple parts using MeshMixer.

Step 15 MMU Single material operation

Did you know that MMU3 unit can also be used to make single-material printing more convenient too?

⬢You can keep up to five of your favorite materials loaded into the MMU unit.

⬢Use the regular MK4S profile, when slicing. The printer will allow you to choose which filament to use, once you start printing.

⬢If you know which of the five materials to use already while slicing, you can use the MMU3 profile and assign a single color (Extruder number) to the object.

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If one of the filaments runs out, your print might be able to continue automatically with the Spooljoin function.

Check the SpoolJoin article for more info.

5. Preflight check

5. Preflight check

Step 1 Filament preparation

Step 2 Suggested filament layout

Step 3 Loading a filament through the buffer

Step 4 Preloading filaments to MMU

Step 5 Closing the buffer

Step 6 Pro tip: Loading using the buttons.

Step 7 Loading test (part 1)

Step 8 Loading test (part 2)

Step 9 Printing a test object

Step 10 Tools Mapping

Step 11 Printable 3D models

Step 12 Print & Follow the Handbook

Step 13 G-code preparation / Custom model preparation

Step 14 Making your own Multi-material models

Step 15 MMU Single material operation

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