LulzBot Mini Review: Compact, Powerful Yet Easy to Use

One of our most frequently asked questions here on the blog is: what is the ideal beginner 3D printer? While there will probably never be a single right answer to this question we try our best by reviewing printers that look like they have the potential to be great beginner machines.

One machine that looks promising in this respect, is the LulzBot Mini. This 3D printer has received rave reviews by 3D Hubs and Make: Magazine. Enough reason for us to get hold of machine to see if it really lives up to expectations.

The LulzBot Mini and its bigger brothers from the LulzBot line of printers are designed and produced by Aleph Objects Inc. The Loveland, Colorado, USA based company is one of the 3D printer manufacturers that is staunchly committed to the open-source movement.

This means that the hardware and software created by Aleph Objects is free to be copied or modified by all users. All software source-code, plans and material lists for each one of the LulzBot 3D printers are made available online for free. In return, Aleph Objects benefits from the improvements that the community comes up with. These are fed back into product development and incorporated into the next generation machines.

Founded in 2011 by Jeff Moe, Aleph Objects today has more than 80 employees and was on track to generate 12 million USD in sales for 2015.

The LulzBot Mini is a moving-bed design printer, with a direct drive extruder, a full-metal hot end, and a heated print bed. The powder coated aluminum chassis has a medium-sized foot print 43 x 34 x 38 cm that makes for a build volume of 3650 cm³. The printer has an open frame design, making it relatively light and portable with a total weight of 8.55 kg.

The machine feeds on 2.85mm filament and its open format filament system combined with its operating temperature range of up to 300°C allows it to print a wide range of materials. The build plate is made of Borosilicate glass covered with PEI print surface and reaches a maximum temperature of 120°C.

LulzBot Mini 3D Printer. Photo © Lulzbot

The LulzBot arrived in a cardboard box with plenty of foam padding to protect it from damage during shipment. Shipped with the printer is a quick-start guide, the power and USB cable, and a handy poster explaining the key parts and features of the machine. Further, you receive a print removal knife, a flathead bristle brush, a dental pick, tweezers, a 2mm Allen wrench and five replacement wiping pads.

The quick-start guide walks you through the steps to get the printer up and running: you first remove any remaining packaging foam then install the Cura software (more on the software below) and configure it. In the Configuration Wizard you simply select the radio button next to LulzBot Mini and you are done.

You then plug in the power cable, the USB cable and power up the machine. As a first print, LulzBot recommends that you print the rocktopus, LulzBot's mascot in the form of an octopus.

The rocktopus is supposed to load automatically the first time you run the software. This was not the case for me such that I downloaded it here. With all the necessary preparation in place it was time to heat up the print head and get down to melting some filament!

The LulzBot Mini ships with a tiny bit of HIPS filament left over in the tool head from quality control. You need to remove this before proceeding to your first print. In order to do so, you heat the hot end to 240°C using the Printer Interface window. You then release the hinged idler by compressing the springs that hold it in place. This releases the filament which can now be pulled out of the tool head.

To install a new filament spool, the filament holder is flipped into an upright position which secures it to the frame of the printer. You then simply slide the filament spool onto the filament holder and push the filament into the feed hole until a small amount of molten material comes out of the tip of the nozzle. The filament is then secured by snapping the hinged idler back into position.

Changing filament on the LulzBot is easy, you sometimes just have to fumble a bit to get the filament into the feed hole. You can't really see the feed hole well as it is somewhat hidden behind the hobbed bolt idler.

Note: the Lulzbot Mini ships without any filament. You need to order this separately when buying your printer. Interestingly, Lulzbot recommends HIPS filament. This is somewhat surprising as HIPS is not that commonly used as primary printing material. Being soluble in limonene, HIPS is typically used as wash-away support material rather than a stand-alone material for complete prints.

For beginners I'd recommend to start with PLA as HIPS can create issues with layer adhesion and cracking. But, I am getting ahead of myself, more on materials is coming below.

The LulzBot makes print bed leveling a breeze since the automated bed-leveling sequence takes care of it for you. When launching a print, the printer will first start heating the print head to 160°C, then wipe the nozzle clean before probing the bed-leveling sensors. Once that's completed the tool head moves into a holding position waiting for the print head to hit the desired printing temperature. At the moment that's reached, printing begins.

The total start-up sequence takes around four minutes. As great as the automated bed-leveling is, it also get a bit annoying over time as the printer always rigorously follows its routine. If you need to stop a print during the first layers and want to relaunch it immediately afterwards, it can't be done. The machine will first cool down, wipe the nozzle, re-probe the bed-leveling sensors before setting off on a new print.

In line with their open-source philosophy, Aleph Objects has chosen open-source Cura as their host and slicing software. You do however get a LulzBot flavoured version called the Cura LulzBot Edition.

I downloaded the latest version of the software from here. I installed it without any issues other than the fact that the interface came in German. Now, this is probably due to the fact that I run a German version of Windows. I'd still have liked the option to switch it to English rather than the software making that decision for me. As a side comment, the German translation of the different slicer settings is not complete as some are still shown in English.

Any user of Cura will recognize the familiar settings, the interface just appears in the brand specific lemon-green tinge and the software is pre-configured for the LulzBot range of 3D printers.

There is not that much to be said about the Cura LulzBot Edition. It works with the same advantages and drawbacks as the regular Cura. For a beginner it is certainly helpful to start off using the Quick Print settings. Once you get a bit more experience though, it pays to switch to Full Settings which give you more control but also require a bit more knowledge. If you really want to dig into the advanced settings, I'd recommend that you download the user manual which describes each slicer setting in quite some detail.

For the more advanced users it might be interesting to know that I also ran the LulzBot Mini using the Simplify3D software (a premium, closed-source slicer and host software package). This worked perfectly fine, the Mini's startup sequence with wiping, preheating and auto-leveling was included out-of-the-box. There was no need to manually paste this into the g-code.

All in all, the LulzBot comes pretty much plug and play. It was a real pleasure to unbox and set up the machine. Without a doubt even a untrained beginner can be up and running in a few minutes only. The quick-starter guide is well illustrated and provides clear step by step instructions, I fail to see how one could go wrong by sticking to it.

At the time when I started working with the Mini, Halloween was approaching. Thus, I decided to throw it in at the deep end and see how it performed. Let me explain: I typically start off by testing a printer with PLA, a material that is comparatively easy to use. In this case, I had a spool of glow-in-the-dark ABS laying around which I had tried unsuccessfully on another printer before.

I was very quickly impressed by how well the LulzBot handled the ABS. It churned out print after print without the slightest hiccup. The prints stuck to the bed, not a single one came lose nor did I experience any warping.

To gauge all aspects of the Mini's printing performance, I used the test protocol from the Make 3D Printer Shootout. Printing the same probes on different printers allows me to compare performance between different machines.

The LulzBot dropped a couple of perimeters on the 4^th and 5^th bridge. A good but not a perfect result. Score: 4/5.

Obviously, I printed a lot more than just the Make test probes on the LulzBot. I tried to print a mix of practical and decorative prints, in a variety of materials, to learn more about the strengths and weaknesses of the machine.

As described above, contrary to my usual way of proceeding I only started using PLA after I had used ABS. As expected, the LulzBot handles PLA well, a moderate print bed temperature of 50°C makes sure that prints stick fine.

I did run into an issue though that is indirectly related to PLA. Read more on that further down.

CorkFill is a PLA/PHA filament compounded with cork dust, produced by ColorFabb. Following the manufacturer's advice to increase the flow rate by +5% and having tweaked retraction a bit, I was able to get prints with a really nice surface finish. I experienced absolutely none of the nozzle clogging that can come with printing wood based filaments.

Just as I was testing the LulzBot, ColorFabb come out with a new co-polyester called nGen. I was able to secure a sample just before the product launched put it to the test.

I got some really great results using nGen which is both testament to the print quality of the LulzBot and the ease of use of nGen. I found that nGen worked well when printed at 235°C, the print bed at 75°C and at a speed of 40mm/s. Read a more detailed review of nGen here.

With the LulzBot Mini having a direct drive extruder, I was keen to see how well it would handle flexible filaments. While the printer managed the first few layers well, all my attempts to print with flex filament failed at some point. Even at very low printing speeds, the filament would buckle eventually, thereby preventing the extruder from being fed properly.

Note: in October 2015, LulzBot brought an new extruder to the market. The so-called FlexyStruder is specifically designed to enable the Mini to work with flexible filaments such as NinjaFlex and SemiFlex. The FlexyStruder tool head has a thicker extruder body and a 0.6mm nozzle allowing for fast and reliable prints with flexible filament.

One thing I noticed after using the Lulzbot for a while was a fine layer of of dust around the top of the tool head. Taking a closer look, I realized that this were material particles stemming from the drive gear. As you can see from the below picture, the edges of the drive gear wear out over time and the drive gear will need replacing at some point.

The drive gear showing signs of age.

A clean metal surface on the nozzle is critical for the automated bed-leveling process to be successful. Therefore, the printer always first wipes the nozzle on the wipe pad before proceeding to probe the four bed leveling sensors located on the edges of the build plate.

I had a couple of cases where the bed leveling failed quite badly: when autoleveling, the nozzle did not seem to recognize when it hit the bed-leveling sensor and kept pushing downwards, bending the print bed. Searching for a solution in the LulzBot forum, I came across a few threads where users complained about this very issue.

The forum did also provide the solution: the problem stems from a nozzle that is not properly cleaned during the wiping process. The solution lies in increasing the cleaning temperature of the nozzle. I simply edited one line of gcode whereby I increased the temperature from 160°C to 170°C. This settled the issue.

Thinking about when these failures had occurred, it was each time when I was printing with PLA. Due to PLA's lower printing temperature, the relative temperature during the nozzle wiping process is also lower. In other words, it is not sufficient to properly clean the nozzle which then fails to make contact with the bed-leveling sensor. So this is a problem that can get solved with a simple tweak but judging by the Lulzbot forum this is something that quite a few people are struggling with.

That being said, during all the time where I worked with the Mini, I had not one single failed print due to delamination which proves that the combination of the print bed leveling and the heated print bed works perfectly. A huge plus for the machine!

With the LulzBot Mini, Aleph Objects had made a very solid extension to their product line. While the company may historically have been known to produce machines that appeal to hardcore Makers, the Mini is a 3D printer that will appeal to beginners and Makers alike.