Introduction: Improving Lulzbot FDM 3D Printers

About: Educator, designer, maker of things

This instructable focuses on working with, maintaining, and modifying Lulzbot printers. Though the maintenance and calibration tips and tricks may be applicable on many FDM printers out there.

There are tons of 3D printer brands out there, as well as many different types of 3D printing technology (FDM, SLA, Polyjet, etc). Personally, I prefer Lulzbot printers, and here's why:

  1. Reliability - I am a 6-8 teacher and K-12 coordinator for engineering education in a school district in NJ. We have 18 3D printers and 5000 students that use them each year. On average we rack up about 3,000 hours on each machine every year. I've worked with Lulzbot, Ultimaker, Makerbot, Stratasys, DaVinci, Prusa, and Flashforge machines in this type of environment and Lulzbots have broke down the least, and were the easiest to get going again for me.
  2. Calibration - This is sort of part of reliability, but it is needed to say that from the TAZ6 and newer, all Lulzbot printers auto-calibrate, level the bed, and clean the nozzle before each print. This is something that is really only available on more expensive printers and makes dependability and ease of use way better than most.
  3. Versatility - Lulzbots come in all sizes, and have endless options when it comes to tool heads for layer height, speed, and material. Newer Lulzbots can print over 30 different materials and 6 different layer heights with the stock head. I've never had an application that wasn't achievable by one of my Lulzbot printers.
  4. Print Quality - As far as FDM printers go, Lulzbots are up there in quality. They out perform cheaper printers like DaVinci or Flashforge and are comparable to more expensive printers like Makerbot, Ultimaker, or even Stratasys.
  5. Cost - Lulzbots aren't the cheapest printers, but when you take the professional-grade reliability and versatility into account, I believe they are a bargain. Lulzbot printers work with any 3mm filament, so getting cost effective filament is easy to do. I typically recommend Lulzbot for high-demanding classroom settings, and advanced or aspiring DIY makers. Prusa printers are my personal second choice, the new Prusa Mini for under $400 is a great performance hobby printer.

Over the years, I have worked with the TAZ4, TAZ5, and Workhorse, and I have owned the Mini 1, Mini 2, TAZ6, and TAZ Pro. These printers are awesome, but nothing is perfect. I have found a few ways to improve their performance and reliability through regular calibration and modified parts.

I hope this helps all Lulzbot users out there, or even other users of FDM printers. Thanks for reading!

Step 1: General Maintenance, Calibration, and Tuning

For all Lulzbot printers, ensuring that everything is well calibrated and tuned contributes to reliability and performance. There's a few things you want to check on a regular basis for all models:

  1. Nozzle - Make sure the nozzle is clean, use maroon scotchbrite and NEVER clean with a metal or wire brush, especially while the power is on. You will ground out the hot end and blow a fuse
  2. Level Washers - These are the metal disks that the nozzle taps to determine the bed level, if these are dirty then the auto-level will not be accurate. Just wipe clean with your finger or a cloth, don't use a wet-wipe as then the nozzle will get wet and may pickup more dirt or dust
  3. Wipe Pad - If the wipe pad is dirty, then the nozzle will be dirty. Later in this instructable, I demonstrate how to replace the OEM skinny felt pad with a scotchbrite pad, but in general clean the pad with your finger nail and dispose of when both sides are clogged excessively
  4. Filament Grabbers - Depending on the model, your printer has different ways of clamping the filament in place and feeding through the extruder. Ensure the grabber tension is not too tight, or too loose. For the Lulzbot TAZ6, Mini 1, and older, I like to keep the idler springs at about 7.5mm out, though this may change over time and based on filament type. For the Mini 2, Aerostruder, and newer models, I like to keep the tension nut one full turn in towards the hot end. In general, I prefer to hold the filament on the loose end rather than too tightly.
  5. Print Bed - You want a dust-free and clean PEI bed. I don't often use glue for printing, but I clean if off regularly every time I do. Clean your bed with 70% Isopropyl wipes on a regular basis and avoid touching it with your fingers. A dirty bed may lead to poor adhesion or excessive wear. To clean glue off, preheat the bed to 80 degrees C before cleaning with wipes.
  6. Z Offset - This is the distance from the nozzle to the bed. It is a common misconception that this offset will never change. Inserting and removing filament, transporting your machine, even the auto-calibration will change your z-height and this should be adjusted on a regular basis. I get more into this in a later step.
  7. E-Steps per MM - this is a ratio of how much the extruder turns in order to feed a set amount of filament. This is something that needs to be adjusted over time, especially from printhead to printhead as it is unique per extruder gear. I get more into calibrating this in a later step.

Step 2: Setting Z-Offset

Is your filament not extruding? Does the bone gear wear into your filament and start stripping on feed mid print? This could be filament tension, or Probe Z-Offset. This refers to the distance from the nozzle to the bed. It is a common mistake that this offset will never change. Inserting and removing filament, transporting your machine, even the auto-calibration will change your z-height and this should be adjusted on a regular basis.

On all models with a graphical controller, you can adjust the Z-Offset right on the printer under:

Configuration - Advanced Settings - Probe Z-Offset

On the original Mini, the Z-Offset has to be set from Cura through a computer connected via USB. On the graphic controllers, there is a nice animation to show you whether you are moving the nozzle closer or farther to the bed. Negative is closer to the bed, positive is farther away or more vertical. Remember to click Store Settings in order to save your changes when done.

To know if the Z is correct, you want to pay close attention to the skirt that prints around the start of your model. If the line is too rounded, it is too high and you want to lower the Z-Offset. If the line is too smooshed, the Z-Offset is too low and must be raised. You want a slightly flattened round line. One that doesn't easily slide off your bed if you run your finger over it. This takes some trial and error to get right, I usually adjust in increments of 0.05mm to test and avoid making a terrible mistake of crashing my nozzle into the bed.

A bad Z-offset could result in a failed print, or poor layer quality, or even extruder jamming if set too low. Always watch the first layer or outer skirt print each time you start a new print to ensure quality.

Step 3: E-Steps Per MM

This is another maintenance routine that is applicable on all printers. Like the Z-Offset, this can be done directly on all printers with a graphical LCD, or a computer connected via USB on those without. Setting the E-Steps per MM can be done under the following menu:

Configuration - Advanced Settings - Steps Per/mm - E Steps/mm

But what is the E Steps / mm, or what does that do? Steps per mm is a ratio of how much the stepper motor rotates to feed or move a set distance. The E steps per mm refers to how much the extruder rotates to feed exactly 100 mm. From the factory, TAZ 6 printers are set to 830 steps/mm, Mini 2's are 420 steps/mm, and other heads may vary but all Lulzbot Print heads are labeled on the back of the print head. This number will change as the gears wear from general use. I have found that the newer Aerostruder or SE style head on the Mini 2, Workhorse, and TAZ Pro wear significantly less than the older style on the Mini 1, TAZ6 or other models with the large plastic 3D printed gears.

Why is setting this important? Well let's say that this setting is off on your printer and it thinks that 830 steps feeds 100mm of filament, but in actuality it only feeds 97mm of filament. Then you will have holes or gaps in your print. Likewise, if it is feeding too much filament, you can actually jam your print head. So how to do we set this?

  1. Load a light color filament into your printer. Place a first mark on the filament it at where it enters the print head with a marker, then a second mark it EXACTLY 100 mm away from the first mark
  2. If you haven't already, preheat the nozzle to an appropriate temp for feeding (say 230 degrees C0)
  3. Feed EXACTLY 100 mm of filament
  4. Place a third mark where the filament stops in the same spot as your first mark, in theory this should be on the second mark but if its not then you need to adjust your E-Steps / MM (good thing you're doing this!)
  5. Measure the distance between the second mark and the third mark. If the third mark is past the second, add this distance to 100. If the third mark is before the second, subtract this distance from 100. This will give you your actual distance travel in mm.
  6. Now a little math. Go to the Esteps / mm menu to see your original Esteps/mm. Using the equation below, you can determine your new Esteps/mm

New E Steps/mm = (100mm * Original E Steps) / Actual Distance Traveled

For example, let's say my original E Steps / mm was 830, and my actual travel distance was 103.4 mm instead of 100 mm as expected. My equation would look like this:

New E Steps/mm = (100*830) / 103.4

New E Steps/mm = 802.7 (round to 803 E Steps / mm

Go ahead and enter your new E Steps / mm in your advanced settings. Don't forget to store your settings!

Step 4: Official Lulzbot OHAI

It would do injustice for me to write this instructable and not point out all the support that Lulzbot provides. The collection of OHAI (Open Hardware Assembly Instructions) created by the Lulzbot team is incredible and can be seen here.

Lulzbot demonstrates how to disassemble and reassemble every single component on each machine in great detail and excellent images. I use these guides when there's odd jams, or even connection issues here and there.

In addition to the OHAI guides, Lulzbot also provides CAD models for all the 3D printed and machined parts on each printer and tool head they make. These come on the SD cards and Drives from the factory, but if you misplaced or reformatted your drive, they are also available on the web here.

It is incredibly easy to print replacement parts and install using the files and assembly instructions provided. In addition, I have personally always found Lulzbots customer support to be excellent and responsive. Just another reason why I prefer this brand.

Step 5: Modification # 1 - Wiper Pad

On all self-calibrating Lulzbot printers, the nozzle cleans its self on a felt-ish wiper pad. It works, but I find that it clogged easily, doesn't do well in cleaning really gummed up nozzles, and is a little too skinny and sometimes the nozzle rubs along the side of the plastic.

Maroon scotchbrite works really well in safely cleaning the nozzle. I created this wiper pad that works on all Lulzbot models, including the Dual V3 printhead on the TAZ6. There are two files, one is the pad holder and another is a template you can use to accurately cut your scotchbrite pads to size.

Print using a high temp plastic like ABS or PETg.

Step 6: Modification #2 - Filament Spool Holders

I am not a fan of the TAZ side mount spool holders, especially when trying to hold two rolls on a dual extruder head. For the TAZ models, I created a side and top mount spool holder.

The top mount spool holders work great for the TAZ6 and Workhorse, they also eliminate the need for the clear plastic guiding bowden tubes and making filament swapping easy. The TAZ Pro has side mounted filament seniors so a top rack is not an option, nor is ditching the bowden tubes. I created this side mount spool holder for my pro, though it would also work on any TAZ model. For both the top and side mounts, use a 3/4" wooden dowel to hold the spools in the holders.

For the Mini and Mini 2, the stock filament spool arm works well, but it can cause extra friction and binding, especially on larger 5kg or 10kg spools. This snap-on spool bushing works on any Mini model.

For any of these parts, you could use any plastic you want really. But if you are transporting your printers on a regular basis, I recommend using PETg for strength and temperature resistance over PLA.

Step 7: Modification # 3 - Extruder Fan Shrouds and Nozzle Socks

On the older Lulzbot print heads (Mini 1, TAZ6, MOARStruder, etc), the cooling fans blew onto the extruder hot end though fan ducts on the side, or sides around the nozzle. On newer print heads found on the Aerostruder, Mini 2, TAZ Workhorse, and TAZ Pro, the extruder is enclosed and a blower fan cools from all four sides around the hot end.

This improves cooling, and improves accuracy of printing difficult sections like overhangs, but opens an opportunity for catastrophic failure. Now remember, I work in a district that has students and a handful of teachers using our Lulzbot machines which may be the the most demanding environment out there. This issue may not occur in a DIYers shop or a facility with professionals using the machines, but still know it can happen.

In the event of poor bed adhesion, a print may slip or slide around the bed and the printer will continue to print. This will cause a flow of "spaghetti" or just fed plastic onto nothing. In the old days on the single sided or individually ducted fans, this was no big deal. The plastic got blown around and you came into the shop the next day to be greeted by a pile of plastic strings.

On the newer enclosed cooling fans, a vacuum is created and that spaghetti gets sucked in and around the hot end to create a solid mess. It is a nightmare to clean off, if you're lucky and the temp wires are in tact you can heat the nozzle and carefully pull the mess off. If not, get out the torch.

I created a redesign fan shroud for the TAZ pro dual extruder, and the Mini 2 SE0.5 OEM print head, which should also fit on the Workhorse though I have not tested it. These blow air from one, two, or three sides like the older print heads. In theory, this may reduce quality though I have not noticed it in a real-world scenario. The upside is that the attack of the glob can no longer occur and that peace of mind is priceless. Print the new shrouds in a high-temp plastic like ABS or PETg.

As an added layer of protection, I would put these socks on the E3DV6 hot ends. If you get a gummed up nozzle, you can pull off the silicon sock for easy cleaning and care.

Step 8: Modification #4 - Octoprint

Octoprint is a linux based operating system for the Raspberry Pi Micro-Computer. Essentially, it allows you to have control over your Lulzbot printer through network connectivity.

Through Octoprint, you can send models to your printers wirelessly, you can start prints wirelessly, you can monitor prints live through a webcam, you can install add-ons like filament run-out sensors, or even modify the functionality and features of your printers with ease.

I am no Octoprint expert, nor do I believe it is completely necessary for a classroom setting. I personally prefer to slice models and save to SD cards for ease of management in my makerspace and to more closely monitor students using the machines. However, I enjoy having Octoprint setup on my Mini at home to print wirelessly. Especially because my original mini is not compatible with the graphical controller upgrade. With a rasperry pi and octoprint, I no longer need a computer to be connected to the Mini for functionality. After configuring your octoprint server, you can add your Ocotprint printer directly to Cura Lulzbot Edition for easy one-click printing.

For setup, I used this tutorial to get Octoprint running on a Raspberry Pi Model 2B pretty quickly and easily. I also added the Octoscreen plugin for a clean user interface using this tutorial. I created this mount to attach the Raspberry Pi and Official Raspberry Pi 7" touch screen to my Mini.

Step 9: Modification #5 - Aesthetics

There's ton of awesome mods out there to make using your Lulzbot printers more fun or even just easier to manage. I have two I want to share:

Extruder fan coversfor a cleaner look, especially on dual head printers.

Mini Tool Caddyfor a clean and organized way to keep all your printer tools right where you need them.

Another useful and fun mod is the addition of LED light strips. If you add Ocotprint as mentioned earlier, you can even have your Raspberry Pi control the LED lights for you. There's tons of mods out there, have fun with it!

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