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Slicer: https://www.prusa3d.com/page/prusaslicer_424/ for Prusa MK3

Material Selection and Configurations

We commonly print in three materials, PLA, PETG, and carbon fiber PETG (commonly called CF PETG on our team). PLA is good for low-stress and low-temperature applications, like cabin seats, and for prototyping as it is inexpensive but not particularly strong with a lower melting point than our other filaments. PETG is good for applications with small loads, like a sensor mount, and/or lots of heat, like an ESC case. CF PETG should be used for any structural prints, like motor mounts, as is it quite strong and has a high melting point. If you expect many iterations to test geometry and fits, it is best to print your prototypes out of PLA or PETG as our CF PETG is more expensive.

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The default settings for “Kimya PETG Carbon” are a good starting point, but we recommend changing them slightly to look like this:

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Plating Parts and Infill Selection

To add a part to the Prusa Slicer, you can either drag your STL file from your computer and drop it into Prusa, or click File>>Import>>STL and select your file from your computer.

Next, you will want to click on the part and select the “place on face” option:

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When you choose what face to place it on, consider if there is a good surface to print up from, if there are any curves that need to be accurate (any holes/circles not printed from the bottom up will not be perfectly round), and what direction the load on the part will be coming from. You will likely want to ensure that the layers are perpendicular to the main force being applied to the part, this prevents your print from shearing apart.

To print multiple parts, you can drag/insert more parts into the slicer, place them on the appropriate face, and hit the icon that looks like a grid at the top of the screen to auto-arrange them.

When choosing infill, consider the load the part will be under. Things like electronic cases can be printed at around 10-15%, while structural parts like motor mounts should be closer to 40-60%. We should never have a reason to print at anything higher than 60%.

If your part is flat or can all be printed straight up without any floating material you can set the supports option to none, otherwise the best option is “supports everywhere”.

Slicing and Starting the Print

When you are ready to print just click Slice Now at the bottom right, you will then see the estimated print time and a graphic showing the layers as they will be printed, including supports. If you’re happy with this, click “Export” and save it onto the printer’s SD card.

Once your print is on the SD card, put it back in the printer, choose “Print from SD” and your part from the list.

Keep an eye on your print for the first few layers and hit the x button on the printer if something goes wrong.

Print Troubleshooting

  • If the first layer isn’t sticking:

    • Clean the build plate with rubbing alcohol

    • Clean the build plate with soap and water, dry well

    • Clean the build plate with acetone (PEI sheets only)

    • Print with a raft

    • Print the first layer at a slower speed

    • Recalibrate it until the filament is coming out the correct amount and adhering to the build plate

  • If filament isn't extruding and/or the extruder is making a clicking noise

    • Check that the correct extruder temperature is set

    • Unload the filament, cut the end, and reload the filament

    • Recalibrate first layer

    • Check nozzle for jams by inserting needle into the end, there are needles in the red bins next to the printer

  • If print won't come off the print bed

    • Put the print bed in the freezer and wait 20 minutes, then try to remove print again

    • Flex the print bed

    • Heat the print bed again and try to remove the print

    • If it is still stuck, use acetone, this will ruin the print but will save the more expensive bed

Updating Firmware

You need a USB B plug to update the firmware. Look in the cable bins on the electrical shelf to find one, and follow this youtube tutorial: https://www.youtube.com/watch?v=h4IrBGgJa90