Printing with Rigid and Flexible Filaments

LulzBot have released the Aerostruder for both Mini and Taz Printers now (Mid 2018). It features a Titan Aero Extruder from E3D, which makes it capable of printing in flexible filament and rigid filament, depending on the situation! It's an awesome upgrade for anyone that prints regularly and worth checking out!

Also, the Dual Extruder v3 supercedes the v2 below, and due to the updated design, means it can also print both flexible and rigid filaments! That means that the options you've got are fewer, but the capabilites of your printers are greater! Sounds good to us.

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So we have had a lot of interest in the additional tool heads for the Lulzbot machines, especially the flexible filament extruders. There are a few questions that come along with the possibility of the further investment into 3D printing. We think it’s worth clearing the air, and making sure you know what you can and cannot print with the optional tool heads.

You have 4 potential tool head options when printing on a Lulzbot machine. For the Lulzbot Mini, you only have the Single Extruder options (that’s the flexible and normal extruders). Also, bear in mind that you receive the single extruder with your printer:

1. Single Extruder Tool Head
2. Dual Extruder Tool Head
3. Flexystruder Tool Head
4. Flexxydually Tool Head

We are going to give you guys a brief description of the limitations of all of these tool heads and identify what filaments you should be printing with each one.

What do we mean by rigid/flexible filaments?

Flexible filaments are one of the newer filament types to hit the 3D printing market and they come with an array of questions surrounding their usage.

The standard “rigid” filaments, the stuff we use with the stock tool heads, is hard enough to be pinched and pushed directly down and out of the hot end. It is quite simple and works great for FDM printing. Flexible filaments, however, are soft and bendable prior to extrusion, making this “pinch and push” approach quite difficult. To assist in guiding the bendy, rope-like filament through the extruder, a PTFE guide tube is placed down through the extruder. There is a notch in the tube for the same pinch and push approach but the tube keeps the filament from bending all over the place.

There’s a clear divide between flexible capable extruders and ‘regular’ extruders. The reason is that the rigid filaments are physically harder than the PTFE guide tube, meaning when you press on the filament inside the guide tube it can (and will) grind out your guide tube and render it useless.

The Single Extruder Tool Head

Built with the Taz 5 and 6 in mind, the Single Extruder Tool head comes with a Taz extruder mount attached for a simple (1-screw) installation. The tool head uses a 0.5mm Hexagon Hot End and can be loaded with both 1.75mm and 3mm (2.85mm if you are picky) and print all the same. The temperature range of this tool head is at 120-300°C which means you can print anything from PLA through to some of the trickier polycarbonate filaments with ease. You can’t print with the more flexible TPE or TPU filaments on the Single Extruder out of the box, though, you’ll need a Flexystruder if that’s what you are looking to do.

Takeaways of the Single Extruder:

• 0.5mm Nozzle Diameter
• 1 Filament at a time
• 120-300°C Temperature Range
• Taz standard mount
• CANNOT print TPU or TPE filaments easily (Not recommended)

The Dual Extruder Tool Head

Just what you think it is, the Dual Extruder Tool head gives you the option of loading and printing with 2 separate filaments at the same time, awesome for multicolored prints. Like the Single Extruder, the Dual Extruder uses 0.5mm Nozzles and comes with additional cooling fans for the extra hot end. A great application for this tool head is the ability to print soluble supports whilst printing your model, making removal of supports extremely easy. The filament constraints are the same too, with the same sizes and types mentioned above being compatible with the dual extruder. Similarly, this extruder won’t be able to print your flexible filaments easily and it’s not recommended to try, we’ll explain a little better down below. Full start to finish guidance for the installation of this tool head can be viewed here.

Takeaways from the Dual Extruder:

• All the features and limitations of the Single Extruder listed above
• Adds the option for printing with 2 filaments during the same print.
• Print soluble supports and make your life easier when it comes to removing your support material.
• CANNOT print TPU or TPE filaments easily (Not recommended)

The Flexystruder Tool Head v2

This is the tool head capable of printing the TPE/TPU filaments. It comes with the PTFE guide tube that enables the flexible filaments to be extruded easily. The entire body of both the Mini and Taz variant are green (unlike the black single extruder) and are specifically made to print flexible filaments. The temperature range is the same as the other tool heads, but it’s recommended you only use flexible filaments with this tool head. Full start to finish guidance for the installation of this tool head can be viewed here.

Takeaways from the Flexystruder:

• Enables you to print with TPE and TPU filaments
• Is not able to print any of the other rigid filament types.
• Comes with a UHU glue stick for bed adhesion and flexible filaments.

The Flexydually Tool Head

This is where the confusion seems to set in, the Flexydually is able to simultaneously print a regular rigid filament and a flexible filament. It has 2 extruders one for flexible filament with all the features of the flexystruder and one for rigid filament with all the features of the single and dual extruder. This means you can print rigid/flexible models in place; such as wheels for your robotics project or parts with gaskets in place. The same rules apply for each of the tool heads in this assembly. Lulzbot recommends this tool head for advanced users that are familiar with most to all aspect of 3D printing. If you want more information on the installation and configuration of this particular tool head you can find it here.

Takeaways from the Flexystruder:

• Enables you to print with TPE and TPU filaments and regular rigid filaments
• Is not able to print 2 of either of the above filament types
• Recommended for advanced users of 3D printing as there are a lot of aspects to consider when printing with a mix of flexible and rigid filaments.

I hope this summary of the tool heads and their usages helps you out in deciding which upgrade you get and informs you completely on the limitations of any upgrades. If you have anything you want to add let me know in the comments section below.