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Following is all of the info needed to get your assembled LulzBot Prusa Mendel 3D printer up and running. This wiki page similarly matches the info found in the instructions sheets you have received with your printer. You will also find additional information here including updates, images, and videos. Please read all of the information found here or in the printed information sheets before unpacking or powering your printer.


Read these warnings before unpacking or powering up your printer. This 3D printer is a machine with motorized and heated parts. When the printer is in operation always be aware of all possible hazards.

Never touch the electronics board when the printer is powered. Always power down the printer and completely turn off and unplug the power supply before touching or removing any wires from the electronics board. NEVER touch the screw terminals on the power supply when the AC plug is plugged into a power socket.
Never touch the extruder nozzle or heater block with out first turning off the extruder heat and allowing it to cool for at least 10 minutes. Also do not touch plastic extruding out of the hot end nozzle. The plastic can stick to your skin and cause burns. Also beware of the heated bed which can reach up to temperatures of 120C
Never place flammable materials or liquids on or near the printer when powered or in operation.
When the printer is in operation take care to never put your fingers in the moving parts including the belts, pulleys, or gears. Also, tie back long hair or clothing that can get caught in the moving parts of the printer.
For users under the age of 18, adult supervision is recommended. Beware of choking hazards around small children.

Printer Cautions and Tips

  1. The green film on the glass print surface is PET film. Do not remove this film. Printing directly on to the PET film helps the printed plastic stick to the print surface. PET film greatly helps in preventing warping.
  2. Using a mixture of ABS filament dissolved in Acetone wiped onto the print surface will almost guarantee zero warping. The mixture we generally use is 1 meter of 3mm plastic per 350 milliliters of acetone. You will need an acetone safe container. HDPE bottles are a good choice.
  3. Never run the extruder when the hotend is not fully heated to the correct temperature.
  4. Never set the hotend temperature above 230C
  5. If the hotend ever heats above 230C do not run the extruder. Let the hotend cool back down below 230C before resuming extrusion.
  6. Never allow the nozzle to drag on the print surface during X and Y axis movement.
  7. Always turn off the power supply and unplug the USB cable before touching or unplugging any of the wires or motor drivers from the printer electronics.

Lulzbot Prusa Mendel Diagram

Coming soon

Unpacking your 3D printer

  1. Remove the plastic bag containing instructions, cords, and small parts
  2. Remove the top foam padding.
  3. Remove the two side smaller foam pads.
  4. Remove the bubble wrapped power supply.
  5. Grab the top of the wrapped printer on the top center where you will feel two lengths of rods. Holding the top two threaded rods, SLOWLY pull the printer upwards out of the box. The two large side foam pads should fall off when the printer is out of the box.
  6. Set you printer on a stable level surface.
  7. Gently unwrap the pink ESD plastic covering the printer. Lightly lift the printer to slide the plastic wrapping from under the printer.
  8. Using scissors or wire cutters, cut and remove the four ORANGE zip ties. Make sure to not cut any of the surrounding wires or belts.
  9. Open the sealed bag containing the manual and other parts
  10. Find the item list attached to these instructions. Before you move 0n to setting up your printer make sure all of the items on the list are in your package.
  11. Remove the four red clamps above and below the x-end motor mount and idler. See the image below to locate the clamps that need to be removed. You will need a M3 hex key and a 7mm wrench or pliers. This will likely change to hardware that does not need tools, or the tools will be included.

Initial Setup

  1. SDRAMPS placement
    Your printer has been pre-calibrated and tested; however, after unpacking you will need to double check that everything is in order before you print.
  2. You should set your printer on a stable, flat, and level surface large enough for extra space around the printer. Make sure your printer work space is clear of anything that could obstruct the movement of the printer. Make sure there are no flammable fabrics or liquids near the printer space. It is also best to not put your printer near a drafty window or air conditioner vent.
  3. First check for any nuts or screws that have come loose. If you find anything loose, make sure to tighten it back. You just need to snug tighten the nuts.
  4. Power supply plugs
    Check that the three mechanical end-stops (they are small lever switches) are aligned to contact with the respective ends. The X-axis end-stop should make contact with the side of the x-carriage; Y-axis end-stop should make contact with the aluminum bed mount plate; Z-axis end-stop should make contact with the bottom of the X-axis idler.
  5. Make sure none of the wires have come unplugged from the RAMPS electronics board. If any wires have come unplugged in shipping or unpacking please see the reference image on the wiki page to find where the unplugged wire(s) needs to be plugged back in.
  6. Power supply plugs plugged together
    Remove the SDRAMPS module from its bag. Plug in the SDRAMPS module into the 2x8 female plug on the bottom right of the RAMPS board. The image to the right shows the location and orientation of the SDRAMPS module after installed on the RAMPS electronics
  7. Unwrap the power supply, USB cable, and sample plastic filament.
  9. Plug the loose black plug coming from the printer into the black plug from the power supply. See the images to the right.
  10. Set the AC power setting on the side of the power supply. You will need to set it to 110V or 220V depending on your location.
  11. Plug in the USB cable, B plug (squarish plug) side, into the USB receptacle on the printer electronics. Plug the other end of the USB cable, A plug side, into your computer.
  12. Make sure the printer power switch is turned off (the circle side should be pushed down). Plug in the green RAMPS power plug from the power supply into the matching green receptacle in the RAMPS electronics. Make sure the screw terminals on the plug are facing up. Now you can plug in the AC power plug from the power supply into an AC power outlet.

Getting software

  1. Most free open-source software can be found at or by searching the software name and Github in a web search engine. Otherwise, you can find wiki pages for software on
  2. There are two basic software types you need to run your 3D printer. One is the host software which interacts with the printer sending instructions and receiving information. The other software needed is the slicer. The slicer software takes an .stl 3D model file and slices it into layers creating a .gcode file. The gcode file is instructions for the printer on how to print the 3D object. The.gcode file is sent to the printer through the host software.
  3. For a great reliable host software get Printrun. Your RAMPS electronics have already been flashed with Sprinter firmware which is completely compatible with Printrun. The file in Printrun you will need to run is
  4. There are two options for 3D model slicers. The older software, SFACT is based off of the Skeinforge slicer. SFACT can be somewhat complex but is documented well and works great. Slic3r a newer slicer is currently in early development but is working. Slic3r is a much faster and easier slicer for beginners.

To find more information on how to use the slicer software to slice your own 3D models, more information on the Printrun software, and a place to find more 3D models visit the links below:

General printer settings

These settings are default and can change with future firmware updates or due to your own updates and hacking. Extrusion temperatures may vary with different plastic filaments

  1. Nozzle temperature: 220C for printing ABS or 185C for printing PLA
  2. Bed temperature: 110C for printing ABS or 60C for printing PLA
  3. Pronterface manual extruder speed: 80mm/min
  4. Pronterface manual X and Y speed: 3000mm/min
  5. Pronterface manual Z speed: 200mm/min
  6. Print area: 170mm(X) by 160mm(Y) by 100mm(Z).

Printing your first print!

These instructions are for use with the Printrun host software. It is recommended to use Printrun for this first print test. If you use a different host software you will need to find instructions on starting a print with that software.

  1. After following the Setup instructions, the printer is now ready to be powered.
  2. Click the power button to the on position to turn on the 12V power
  3. Launch Printrun ( or your host software if you are using something different than Printrun.
  4. Set the connection speed to 115200. In Printrun the connection speed is at the top left of the screen in the pull down menu to the left of the @.
  5. In the top left of the Printrun window, in the Port pull down menu you will need to select the correct USB port for your printer. Generally you will only have one listed USB port. Depending on your computer operating system the name of the port can have differing names.
  6. Now press the Connect button to connect Printrun to your printer. You will know your printer is connected by seeing “Printer is now online” in the print line window on the right in the Printrun window.
  7. Now to set the hotend and bed temperatures. Both settings are near the bottom left. The heater temperature is for the hotend and bed for the bed. To set the temperature, type the temperature you would like in the temperature text box and press set.
  8. After setting both temperature settings click the Monitor Printer button. This will periodically print the current hotend and bed temperature in the print line window. Let the hotend and bed heat up to the wanted temperature.
  9. While the hotend and bed is heating up, home all three of the axes. Press the home button for each axis leaving the Z axis to home last. The axis will move in the negative direction until it touches the endstop switch.
  10. Your printer comes with an SD-RAMPS and SD card. We have put a few test .gcode files on the SD card for you to quickly make your first test prints.
  11. Once you have homed the axes and the hotend and bed have heated to the correct temperature it is time to print!
  12. Click the SD Print button. An SD file selection window will appear. Select the whistle.g file. Press OK to start the print.
  13. When the print starts make sure the first layer is not printing to close or too from the print bed. If the first layer is too high or low you can pause the print and adjust the Z-axis endstop. After making adjustments you can home the axes and press Restart to restart the print.
  14. After the whistle is finished printing, the heated bed will automatically cool down to 60C. If you are printing PLA you will need to turn the heated bed off. Once the bed cools you can you pop the finished whistle off of the printed surface.
  15. If you would like, you can now print some of the other sample gcode files on the SD card. Make sure to reset the heated bed to the correct temperature before starting the next print.

Powering down the printer

  1. Set both the hotend and bed temperature to 0C.
  2. Press the Disconnect button to disconnect Printrun from your printer.
  3. Click the printer power switch to the off position.
  4. Unplug the USB cable from the printer.
  5. Unplug the AC wall plug from the socket.
  6. Make sure the printer has completely cooled before leaving it unattended.


You will need to peform maintenance on your 3D printer periodically. The rate of maintenance will depend on how often you use the printer. Your print settings can also affect how often you will need to perform maintenance on the printer. One instance of this is printer speed. If you are printing at high speeds the PLA bushings will heat faster from friction and wear faster. Note: even when printing at higher speeds it will be months before the PLA bushings will possibly need to be replaced.

Following are a few maintenance steps that should be performed as needed:

  • Periodically check that none of the nuts or bolts have come loose. Through vibrations from movement during prints, fasteners can come loose over time
  • Check that the motors are still tight on the motor shafts
  • Use a rag or towel to remove any build up on the hotend nozzle or heater block. If needed you can use a small amount of acetone on the rag to clean away melted plastic from the hotend.
  • The PET tape that is on the glass bed when you receive your printer will eventually need replacing. If you get any tears or plastic is no longer sticking to the tape it is time to replace the PET tape. We have 2" wide rolls of PET available on
  • Over months of printing the PLA bushing will begin to wear. The great thing about PLA bushings is that you can just print replacements! You can get the boltable PLA bushing file here. You will need to print 12 bushings to replace all of the bushings. It would be wise to print at least one set of PLA bushings as soon as you get your slicer settings tuned in. It is always best to have an extra bushing around rather than having to find someone else with a printer to get you a replacement.