Octoprint and Lulzbot mini operation

Connecting to Ocroprint:

If you’re inside of denhac connected to the Wi-Fi, you can access the instances using this URLs:

For the Lulzbot Mini, OctoPrint is running off of a Raspberry Pi (https://www.raspberrypi.org/) connected to the printer via USB.

Uploading a model:

OctoPrint previously had a built-in slicer, but that was difficult to maintain for both us and the developer of OctoPrint, so the built-in slicer has been removed. Instead, you’ll need to use Cura Lulzbot Edition for the Lulzbot Mini See the sections below for more information on that.

Uploading GCode:

Currently, all users have access to any other user’s folder. Hopefully, a future change will help with that, but for now… no peeking. The “Files” menu (see the image to the right) normally holds everyone’s folder, but I’ve already clicked in through my folder. If your folder doesn’t exist, click the create folder button, give it your username, and then click through.

Once you’ve got your sliced gcode file you are ready to import into Octoprint! We keep a bookmark within Chrome titled “Mini Inside” This will take you to the Octoprint app. If this is your first time logging in you’ll want to create a folder for yourself to store your print. Please be respectful of other people stuff and dont add or delete anything in someone elses folder. Now that you have your folder, Click the (upload?) button. Navigate to wherever you saved the object and (import?)

Loading and unloading the filament:

You will need to swap out the filament whenever you want to use a different color or material. On the “Control” tab you can use the x access (left and right) directional arrow controls to center the print head to give you more room to access the printhead and filament feed. If you need to adjust the height of the print head use the up and down z arrows. To move the print bed use the up and down y access buttons. The home button will return the print head to its “home” position.

First we need to unlatch the clamp that holds the filament in place. The latch is held in place from the pressure of the springs. Pull back and up on the latch against the springs until the latch clears the top corner of the gray clamp.



Now we must heat up the printhead to allow the removal of the hardened plastic. In the pictures I am using ABS which we can see on the spool label has a print temperature of between 220 and 260 degrees celscius.

To remove the filament you can either use the preset temperature under the dropdown of the target temperature panel on the temperature tab pictured here:

or you can set it manually to within the recommended print temperature of the material then click the checkmark button.

In the temperature tab you will see the target temperature as a faded line with the fully colored line representing the actual temperature. Once the actual temperature line has climbed to meet the target temperature line we can safely remove the filament. To do this gently pull the filament till it clears the housing.

Once you have removed the filament be a good citizen and thread it through the hole in the spool for the next user.

Often the filament will not remove cleanly from the printer. If the filament you are loading does not have a clean angled tip, use a pair of clippers to cut the end off.

Now that the filament has been loaded we need to purge any remaining filament of the previous spool. To do that first make sure that the print bed is centered under the printhead. This can be done by adjusting with the arrow buttons within the “Tool” panel of the “Control” tab.

Once it is centered we can begin purging the remaining filament. 25 mm is the recommended amount to extrude at a time while purging however it will often take several clicks to fully purge.

Once the filament no longer shows traces of the previous color you are set to start using the new filament.

If you are simply changing the filament please without actually printing, remember to now set the temperature to 0 on the temperature panel or select “Off” from the dropdown:

The Lulzbot mini has a 152 mm x 152 mm x 158 mm print area. The print bed is heated and uses a PEI sheet to help the plastic stick well to the bed. It uses 3 mm filament (2.85 mm is the same) and has a 0.35 mm nozzle.


Before printing the mini will execute the homing sequence. We advise monitoring this process as you will sometimes be able to catch a failed print early. During this process the printer touches the metal contacts at the four corners of the bed moving counterclockwise to orient itself in space. It will then wipe the nozzle on the cleaning strip located at the back edge of the bed. The print head then does a dog leg up and to the left which signifies the end of the homing sequence. If any of these steps do not occur then you may want to consider canceling the print and retrying. If the homing sequence is continuously failing and the print is subsequently failing please contact a printer manager to perform maintenance.

Once the homing sequence has completed successfully we recommend monitoring approximately the first three layers of the print to check for other unexpected behavior. The majority of failures will happen within the first three layers so monitoring these will prevent you from returning to a smoldering pile of plastic ooze.

Now your print should proceed successfully. If at any point you notice that the print has gone awry you should cancel the print, clean the print bed and start over. Unfortunately this does happen from time to time. If this begins to happen consistently please contact a printer manager who will fix whenever they are able.

When the print has finished please remember to log out of octoprint and shut down the printer using the red button on the front of the frame.

Importing and slicing an object with Cura Slicer Lulzbot edition

Opening Importing and Setting Up:

On opening or creating a new project will give you a workspace like this:

To import an STL file select Open File(s) from the File menu like so:

Editing and Manipulating Objects:

When initially opened the model should appear centered on the print bed in the display. If the model is outside of the printable area it will appear with caution lines covering it as pictured here:

To fix this, just click on the green “move” icon then click, hold and drag the model until it is where you want it on the print bed. Our model still has caution lines because it is too big to fit inside the print bed. If the exact size is unimportant you can select the “Scale” icon to adjust the size. Once “Scale” is selected, you can either adjust using the input boxes next to the corresponding access or just drag along the corresponding axis bar within the workspace. As long as “Uniform scaling is selected the object will do just that.

Now that the model fits within the print bed it turns blue:

If you need to inspect from different angles you can right click and hold while dragging to manipulate the view.

f you suspect that the object should have a different orientation during printed from the one it was imported into you can select the “Rotate” icon. Again the object can be manipulated by either entering a number of degrees to rotate by, within the corresponding axcesses(?) input box or just hover over the axis in the workspace and drag along it. Below we clicked and dragged along the blue Z access to rotate our object.

The other tools in the green toolbar are “Multiply Object” and “Mirror Object”. They pretty much do what you think.

Print settings:

Several preset profiles have been set to make printing quick and easy. It is recommended that you stick to these and avoid adjusting other settings apart from the material dropdown and the ones listed below until you have a little more experience and can comfortably predict what adjustments to the different settings will do. The three main profiles are fast, standard and high quality as pictured here:


Then you will need to select a type of material from the material dropdown pictured here:


If you do any need to adjust any settings they will most likely be Infill, Support, Brim.

  • Infill:

This determines how much plastic will be used to fill the interior of the object. For a simple sculpture a 20% infill will typically be sufficient. For something like a lithograph you will want to increase the infill to something like 80%. This prevents any kind of pattern shining through when illuminated.

  • Support:  

Enabling support is important if you have overhangs that would otherwise be unsupported while printing. The print will remain hot while printing causing any unsupported areas to droop or collapse. We recommend leaving the support at the default settings unless given explicit instructions along with the print In order to view the support you will need to select the layer view.

  • Brim:

If you experience any warping at the edges of your print or if the print is not adhering properly you may want Cura to generate a brim for you. Some adhesion issues can also be addressed by giving the bed a quick wipe with acetone before beginning the print.

Saving and Exporting to GCode:

The slicer automatically begins slicing during periods of inactivity but will pause then restart after any edits are made:

Once you’re happy with the settings and Cura indicates it has finished slicing you can now save the object as gcode file.

A quick note: Unfortunately neither time estimate from the Cura slicer or Octoprint can be relied on so don’t use those to make plans.

Lulzbot Mini: Getting Started


The LulzBot Mini is a fused deposition modeling (FDM) 3d printer made by Aleph Objects. Our printer is the v1 version of the printer with a 152 mm x 152 mm x 158 mm build area. That means that the print bed is 152 mm by 152 mm and you can print an object that is 158 mm tall. The nozzle, by default, is 0.5 mm but has been upgraded to a 0.35 mm nozzle. That means the printer can spit out a 0.35 mm bead of plastic, give or take. The plastic that is fed in is 2.85/3.00 mm, and there are certain plastics that should be used with the Mini to help preserve the knowledge from damage. The Mini runs off of a Raspberry PI running OctoPrint, and you can read more on this page to find out how to access and use it.

How do I use it?

The printer is available for member use only. We’re currently trying to see if we can teach through a wiki and have people take a test to prove competency with the printer. This is that wiki page. The sections under learning will go over the steps to print a model, common safety information, and gotchas. After that, you’ll take a quiz and we’ll get you set up to use the printer.


General safety warning

While 3d printers are fairly ubiquitous at this point, they still have potential to burn our space down. Please don’t be that person. A 3d printer nozzle will reach temperatures of 230 degrees Celsius or 450 degrees Fahrenheit and the bed will reach 100 degrees Celsius which is the boiling point of water. Touching either of these at any time could be very dangerous, because you will be burnt before you realize you are burnt. You can almost never be sure if the printer has been heated recently, so it is best to always assume that the nozzle and/or bed is hot.

Since a 3d printer does have moving parts, it is possible that the printer could move in such a way to pinch your hand or fingers. Avoid putting your hand inside the machine unless you have to to remove a part. The absolute worst case of this is that the hot nozzle is going towards the bed while your hand is there. That hurts. A lot.

Technically, you should avoid touching the bed regardless if it’s hot, because the oils from your fingers can mess with the (Polyetherimide) PEI material on the bed. This bed can also crack or the glass underneath can crack, which means the printer is unsafe to use and the contact above should be informed about it.

Finally, while we do understand printers can run unattended, the risk increases for people who are new to printing, and may try to print a model that could have issues further into the print. For that reason, the first 3 times you print, do not leave the printer unattended. After that, please stay for the first few layers to make sure the print is sticking to the bed and isn’t on fire. I would very much prefer you to stay the entire print every time, but I recognize that that is not always feasible.

Basic 3d printer info

A 3d printer is an additive manufacturing machine. That means it builds an object by adding material bit by bit to make the full object. This allows you to make objects you wouldn’t be able to make by other means, but it also has its limitations. We’ll go into those limitations a bit later, but for now just keep that in mind as I oversimplify this explanation.

For information on our COVID-19 response, click here.